United States Patent [19]
`Howes
`
`[54] LASER BLOCK BEAM SPLITTER FOR
`MICROSCOPES
`
`[75] Inventor: Allen R. Howes, Walnut Creek, Calif.
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`[73] Asslgnee' TTI Medlcal’ measamon’ Cahf'
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`[21] Appl. No.: 274,874
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`[22] Filcdi
`[51] Int C16
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`Jul- 14, 1994
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`G021; 27/14_ 602B 5/O4_
`(10213 27/02
`[52] US. Cl. ......................... .. 359/629; 359/835; 359/480
`[58] Field of
`662490’ $832’
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`[56]
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`References Cited
`U.S_ PATENT DOCUMENTS
`
`'
`1
`4499 897 2/1985 R
`128/303 1
`4’561’436 12/1985 Mousse 1 """""""""""""" " 128/3O3‘1
`4’633’872 H1987 011;: it ' ' ' ' '
`‘ ' ' " 128/303'1
`4’657’013
`4/1987 Hoerenz at
`'
`128 303:1
`4:68g:9O7
`8/1937 Kleinberg __________ __
`350/516
`4,711,542 12/1937 Ichihashi et a1.
`351/221
`4,786,l55 11/1988 Fantone ............. ..
`359/629
`4,827,125
`5/1989 Goldstein .............................. .. 250/234
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`lllllllllllllllllllilllllllllllllllllllllllllllllllllllllllllllll
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`528426A
`[11] Patent Number:
`[45] Date of Patent:
`
`5 528 426
`9
`9
`Jun. 18, 1996
`
`.... .. 351/214
`4,877,321 10/1989 Ichihashi et al. .
`.. 359/375
`4,991,947
`2/1991 Sander ........ ..
`.. 359/375
`5,052,789 10/1991 Kleinberg ..
`-- 359/481
`5,078,469 H1992 Clark ------- --
`.... .. 606/5
`5,098,426
`3/1992 Sklar et al.
`.. 356/318
`5,127,730
`7/1992 Brelje et a1. .... ..
`358/93
`5,264,928 11/1993 Howes .... ..
`5,438,456
`8/1995 Grinblat ................................ .. 359/835
`_
`_
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`Primary Exammer—Georg1a Y. Epps
`Assistant Examiner—-Ricky Mack
`Attorney, Agent, or Firm—T0wnsend and Townsend and
`Crew
`ABSTRACT
`[57]
`A laser block beam splitter system for microscopes com
`prising a main body housing, a laser safety ?lter, two optical
`trains, a pair of beam splitters, and three viewing stations.
`The beam splitters provide an image along both an axial
`beam path and a transverse beam path relative to the main
`body housin . The laser safety ?lter is disposed at the distal
`g
`portion of both optical trains before the pair of beam splitters
`to protect the viewing stations from laser radiation. The
`three viewing stations of the laser block beam splitter system
`are thereby continually protected from laser radiation by the
`laser Safety ?lter
`
`20 Claims, 4 Drawing Sheets
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`1
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`TIFFANY 1015
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`U.S. Patent
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`Jun. 18, 1996
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`Sheet 1 of 4
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`5,528,426
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`FIG. 1
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`2
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`US. Patent
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`Jun. 18, 1996
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`Sheet 2 of 4
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`5,528,426
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`FIG. 2
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`3
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`US. Patent
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`Jun. 18, 1996
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`Sheet 3 0f 4
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`5,528,426
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`FIG. 3
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`4
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`US. Patent
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`Jun. 18, 1996
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`Sheet 4 of 4
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`5,528,426
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`22,4 ‘
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`34A
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`24A
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`nu 0:
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`_
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`2 w
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`FIG. 4
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`5
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`5,528,426
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`1
`LASER BLOCK BEAM SPLITTER FOR
`MICROSCOPES
`
`BACKGROUND OF THE INVENTION
`
`2
`optical head for observation and treatment of an eye with a
`laser is shown in US. Pat. No. 4,499,897. A medical laser
`ophthalmic device having a safety stop shutter is shown in
`US. Pat. No. 4,561,436. A system for precision laser surgery
`is shown in US. Pat. No. 5,098,426. A confocal scanning
`laser microscope having no moving parts is shown in US.
`Pat. No. 4,827,125. A beam splitter having three identical
`optical trains and four viewing stations is shown in US. Pat.
`No. 4,688,907.
`
`SUMMARY OF THE INVENTION
`
`The present invention overcomes the limitations just
`described by providing a microscope beam splitter with an
`integrated laser safety ?lter. The laser block beam splitter
`system comprises a main body housing, two optical trains
`with an integrated laser safety ?lter and three viewing
`stations. The axial viewing light entering the two optical
`trains pass through the laser safety ?lter. The axial ?ltered
`light then travels to beam splitting optics which re?ect a
`portion of the axial ?ltered light along a transverse beam
`path to each lateral port of the main body housing. A
`binocular viewing tube is typically mounted to the primary
`viewing port of the main body housing. The two transverse
`beam lateral ports permit mounting of additional viewing,
`video and 35 mm camera attachments.
`In a particular aspect of the present invention, the laser
`safety ?lter is an integral part of the axial beam path optics
`where each of the three viewing ports permit continual, safe,
`unobstructed viewing through the microscope during laser
`activation. A particular advantage of the present invention is
`that video and 35 mm camera documentation will be free
`from optical obstruction caused by a mechanical shutter
`assembly.
`In another aspect of the present invention, by integrating
`a laser safety ?lter into a beam splitter assembly, the
`physical mass of the equipment is minimized and the
`potential electronic and manual failure of a beam block
`shutter is eliminated.
`A further understanding of the nature and advantages of
`the present invention may be realized by reference to the
`remaining portions of the speci?cation and the drawings.
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`FIG. 1 is a perspective view illustrating a laser block
`beam splitter system constructed in accordance with the
`principles of the present invention and mounted between the
`body and primary viewing tube of the microscope;
`FIG. 2 is a perspective view of the laser block beam
`splitter system of the present invention;
`FIG. 3 is an exploded view of the laser block beam splitter
`system of the present invention; and
`FIG. 4 is a cross-sectional view of the laser block beam
`splitter system of the present invention.
`
`DESCRIPTION OF THE SPECIFIC
`EMBODIMENTS
`
`As illustrated in FIG. 1, a laser block beam splitter system
`10 may be mounted between a microscope body MB and a
`primary viewing tube PVT. A lateral viewing tube LVT and
`a video camera VC are shown connected to the lateral ports
`of the laser block beam splitter system. The microscope
`body and viewing tubes are conventional and available from
`commercial suppliers such as Carl Zeiss, Inc. As will be
`discussed in detail below, laser block beam splitter system
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`10
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`15
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`25
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`1. Field of the Invention
`The present invention relates generally to optical equip
`ment, and more particularly to a laser block beam splitter
`system for microscopes suitable for protecting the viewing
`stations from laser light radiation.
`Medical and research microscopes frequently incorporate
`beam splitter assemblies to permit additional viewing, video
`and 35 mm camera attachments. Commonly available beam
`splitters have two optical trains and provide two lateral
`optical viewing ports in addition to the primary viewing
`port. Such beam splitters are available commercially from
`microscope suppliers such as Carl Zeiss, Inc., Leica, Storz
`and Topcon.
`In order to safely use a laser while viewing through a
`microscope, the prior art has provided a mechanical shutter
`assembly to be mounted between the beam splitter and the
`microscope body. Such mechanical shutter assemblies are
`available commercially from laser suppliers such as Coher
`ent, Laserscope, Sharplan, Nidek and Carl Zeiss, Inc.
`While functional and useful, such beam splitter and
`mechanical shutter assembly combinations restrict the view
`of the primary and lateral viewing ports when the laser is
`activated. The restricted view is caused by the mechanical
`shutter assembly which introduces a beam blocking device
`into both optical trains when the laser is activated.
`A particular concern is the desire to provide continual
`unobstructed viewing to all viewing stations while a laser is
`activated. With the present equipment, such continual unob
`structed viewing is not possible.
`An additional concern is the reliability of a mechanical
`shutter assembly to perfectly activate and deactivate at the
`desired moment of use. With the present mechanical shutter
`assemblies, there is the ever present possibility of non
`function due to electronic or mechanical failure. Such a
`non-function could result in severe eye injury to the opera
`tor.
`Another concern is keeping the physical mass of the
`microscope, beam splitter and laser protection mechanism to
`a minimum. When the physical mass is increased, the
`operating comfort and e?iciency of the primary and lateral
`stations are compromised.
`For these reasons, it would be desirable to provide a beam
`splitter with an integrated laser safety ?lter. Such a system
`would provide continual, safe and unobstructed viewing to
`the viewing stations during laser activation. Also, such a
`system would eliminate the possibility of electronic and
`mechanical failures and reduce the physical mass of the
`microscope assembly when using a laser.
`2. Description of the Background Art
`A slit lamp microscope for observing eye tissue having
`linear polarizers is shown in US. Pat. No. 4,877,321. A
`medical dose-integrating device for measuring the illumi
`60
`nation exposure of light-sensitive organs is shown in US.
`Pat. No. 4,657,013. A true multi-color laser scanning con
`focal imaging system for microscopes is shown in US. Pat.
`No. 5,127,730. A medical apparatus for detecting oph
`thalmic diseases using lasers is shown in US. Pat. No.
`4,711,542. A medical laser optical delivery device having a
`blocking shutter is shown in US. Pat. No. 4,633,872. An
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`35
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`5,528,426
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`10
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`20
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`3
`10 includes a number of components which permit the three
`viewing stations of the system to be continually protected
`from laser radiation.
`Referring now to FIG. 2, the basic construction of the
`laser block beam splitter system of the present invention will
`be described. The system includes a main body housing 12,
`which is generally cylindrical in shape and has a distal end
`14 and a proximal end 16. At the distal end of the housing
`is a distal plate 18. Distal end 14 of the laser block beam
`splitter system is mounted to microscope body MB. At the
`proximal end of the laser block beam splitter system is the
`primary viewing port which may accept primary viewing
`tube PVT as shown in FIG. 1.
`The main body housing de?nes axial passages 20A and
`20B through which two optical trains proceed to the primary
`viewing port. Beam splitters within main body housing 12
`split the light in each optical train along a transverse beam
`path to two lateral viewing ports 22A and 22B. The lateral
`viewing ports extend from the side of the main body housing
`and each has a conventional locking ring 24A and 24B,
`respectively. The locking rings are used to secure lateral
`viewing tubes, video cameras and 35 mm cameras to the
`lateral viewing ports.
`In FIG. 3, the main body housing is shown separated from
`distal plate 18. Disposed on the distal plate are the beam
`splitters 26A and 26B. The beam splitters are depicted as a
`pair of opposed prisms, but‘it would also be possible to
`utilize a single prism, a partially re?ective mirror, a pivot
`able mirror, or any equivalent structure which would par
`tially re?ect axial light along a transverse beam path.
`In FIG. 4, a cross-sectional view of the laser block beam
`splitter system of the present invention is shown. Distal plate
`18 contains a pair of laser safety ?lters 28A and 28B. Each
`laser safety ?lter is secured to the distal plate by a retaining
`ring 30A and 30B. Although two laser safety ?lters are
`shown, one for each optical train, it would be possible to
`utilize a single laser safety ?lter.
`‘The operation of the laser block beam splitter of the
`present invention will now be discussed in reference to FIG.
`4. Axial viewing. light enters along beam paths or axes 32A
`and 32B into the laser block beam splitter at the distal end.
`The axial viewing light is then ?ltered by laser safety ?lters
`28A and 28B. The laser safety ?lters ?lter out or block laser
`radiation that may be harmful to the operator or equipment
`at the viewing stations. For example, an integrated laser
`?lter that attenuates light in the range of 450 nanometers to
`550 nanometers is utilized for use with a commonly avail
`able Argon laser.
`The axial ?ltered light then reach beams splitters 26A and
`26B. The beam splitters let a portion of the axial ?ltered light
`pass through along beam paths or axes 32A and 32B to the
`primary viewing port, which is located at the proximal end
`of the laser block beam splitter system. Beam splitters 26A
`and 26B also re?ect a portion of the axial ?ltered light along
`transverse beam path axes 34A and 34B, respectively. The
`transverse re?ected light proceeds to the lateral ports of the
`laser block beam splitter system. The lateral viewing ports
`can accept a lateral viewing tube LVT, video camera VC, 35
`mm camera, or any other conventional microscope attach
`ment that can be secured with conventional locking rings.
`In one embodiment, laser safety ?lters 28A and 28B are
`coated with a ?lm that allows the ?lters to be substantially
`optically clear (e.g., less than 5% light loss) until energized
`by laser light. Laser ?lters of the type described are available
`from a number of different manufacturers.
`The laser block beam splitter of the present invention
`preferably has the laser safety ?lters in the axial viewing
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`25
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`60
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`4
`light path before the beam splitters so that one ?lter blocks
`laser radiation along two beam paths. However, a laser
`safety ?lter could be placed after the beam splitters at each
`viewing port. Although this con?guration may add weight to
`the system, each viewing port would be continually pro
`tected by laser radiation.
`Although the foregoing invention has been described in
`detail for purposes of clarity and understanding, it will be
`obvious that various modi?cations, alternative construc
`tions, and equivalents may be used. For example, the block
`ing range of the laser ?lter, the number of optical trains,
`number of viewing ports, and type of beam splitter may be
`varied yet still be within the spirit of the invention. There
`fore, the above description should not be taken as limiting
`the scope of the invention as de?ned by the following
`claims.
`What is claimed is:
`1. A beam splitter system for a microscope, said system
`comprising:
`a main body housing having a proximal end, a distal end
`and a lateral port, said distal end couples to a micro
`scope body, said proximal end receives a ?rst attach
`ment, and said proximal and distal ends de?ning an
`axial beam path;
`a beam splitter located within said main body housing,
`said beam splitter oriented to receive light along said
`axial beam path and to re?ect a portion of said light
`along a transverse beam path to said lateral port; and
`at least one ?lter mounted within said main body housing
`so that light leaving said system along said axial and
`transverse beam paths is ?ltered.
`2. The beam splitter system of claim 1, wherein said beam
`splitter includes at least one prism.
`3. The beam splitter system of claim 1, wherein said beam
`splitter is a pivotal mirror.
`4. The beam splitter system of claim 1, wherein said beam
`splitter is a partially re?ective mirror.
`5. The beam splitter system of claim 1, wherein said ?lter
`reduces laser radiation.
`6. The beam splitter system of claim 1, wherein said
`lateral port receives a second attachment, wherein said
`second attachment is selected from the group consisting of
`a viewing tube, video camera, and 35 mm camera.
`7. A beam splitter system for a microscope, said system
`comprising:
`a main body housing having a proximal end, a distal end
`and a lateral port, said distal end couples to a micro
`scope body, said proximal end receives a ?rst attach
`ment, and said proximal and distal ends de?ning an
`axial beam path;
`a laser safety ?lter mounted within said main body
`housing so that light along said axial beam path passes
`through said laser safety ?lter; and
`a beam splitter located within said main body housing,
`said beam splitter oriented to receive said laser ?ltered
`axial light and to re?ect a portion of said laser ?ltered
`axial light along a transverse beam path to said lateral
`port.
`8. The beam splitter system of claim 7, wherein said beam
`splitter includes at least one prism.
`9. The beam splitter system of claim 7, wherein said beam
`splitter is a pivotal mirror.
`10. The beam splitter system of claim 7, wherein said
`beam splitter is a partially re?ective mirror.
`11. The beam splitter system of claim 7, wherein said
`axial beam path includes two optical trains and said beam
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`5,528,426
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`splitter system includes a laser safety ?lter for each optical
`train.
`12. The beam splitter system of claim 7, wherein said
`lateral port receives a second attachment, wherein said
`second attachment is selected from the group consisting of
`a viewing tube, video camera, and 35 mm camera.
`13. A beam splitter system for a microscope, said system
`comprising:
`a main body housing having a proximal end, a distal end
`and a lateral port, said distal end couples to a micro
`scope body, said proximal end receives a ?rst attach
`ment, and said proximal and distal ends de?ning an
`axial beam path including two optical trains;
`a laser safety ?lter mounted within said main body
`housing so that light along said two optical trains
`passes through said laser safety ?lter; and
`two beam splitters located within said main body housing,
`each of said beam splitters oriented to receive said laser
`?ltered axial light along one of said two optical trains
`and to re?ect a portion of said laser ?ltered axial light
`along a transverse beam path to one of said two lateral
`ports.
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`6
`14. The beam splitter system of claim 13, wherein each of
`said beam splitters include at least one prism.
`15. The beam splitter system of claim 13, wherein each of
`said beam splitters include a pair of opposed prisms.
`16. The beam splitter system of claim 13, wherein each of
`said beam splitters is a pivotal mirror.
`17. The beam splitter system of claim 13, wherein each of
`said beam splitters is a partially re?ective mirror.
`18. The beam splitter system of claim 13, wherein said
`beam splitter system includes a laser safety ?lter for each
`optical train.
`19. The beam splitter system of claim 13, wherein said
`laser safety ?lter is approximately 95% optically clear until
`energized by laser light.
`20. The beam splitter system of claim 13, wherein said
`lateral port receives a ?rst attachment, wherein said second
`attachment is selected from the group consisting of a view
`ing tube, video camera, and 35 mm camera.
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`8