CA2065376C - Projection apparatus - Google Patents
Projection apparatusInfo
- Publication number
- CA2065376C CA2065376C CA002065376A CA2065376A CA2065376C CA 2065376 C CA2065376 C CA 2065376C CA 002065376 A CA002065376 A CA 002065376A CA 2065376 A CA2065376 A CA 2065376A CA 2065376 C CA2065376 C CA 2065376C
- Authority
- CA
- Canada
- Prior art keywords
- light
- optical
- projection
- fiber
- image
- 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
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Classifications
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/04—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings formed by bundles of fibres
- G02B6/06—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings formed by bundles of fibres the relative position of the fibres being the same at both ends, e.g. for transporting images
- G02B6/08—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings formed by bundles of fibres the relative position of the fibres being the same at both ends, e.g. for transporting images with fibre bundle in form of plate
-
- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03B—APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR
- G03B21/00—Projectors or projection-type viewers; Accessories therefor
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- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Optics & Photonics (AREA)
- Projection Apparatus (AREA)
- Radio Relay Systems (AREA)
- Optical Couplings Of Light Guides (AREA)
- Devices For Indicating Variable Information By Combining Individual Elements (AREA)
- Optical Fibers, Optical Fiber Cores, And Optical Fiber Bundles (AREA)
- Transforming Electric Information Into Light Information (AREA)
- Optical Elements Other Than Lenses (AREA)
Abstract
A projection apparatus, comprising a fiber-optical plate (1), the entrance faces (2) of the light guides (3) of which coincide with the plane (a-a) of the image of the original, and a projection objective (8), the exit faces (9) of the light guides (3) of the fiber-optical plate (1) being disposed in the field of view thereof. An optical system (10) for concentrating the light rays into a light beam and directing that light beam into the entrance pupil (11) of the projection objective (8) is formed along the path of propagation of the light rays in each of the light guides (3) of the fiber-optical plate (1). The optical system (10) is formed by a focon (12), positive lens (13) and refracting prism (14), disposed successively along the path of the light rays in the light guide (3), while the optical axis (O3-O3) of the focon (12) and the optical axis (O4-O4) of the positive lens coincide with the optical axis (O1-O1) of the light guide (3).
Description
PROJECTION APPARATUS
~ield of the Invention ~hi~ invention relates to optical instrument building, to apparatuses ~or projecting the display of yisual information, more specifically - to projec-tion apparatus.
Description of the Prior Art At the present time work i~ being conducted with the aim of improving ~nown and creating ba~ically new con~tructions of small-size projection apparatuses, which would make it possible to obtain a high quality reproduced image on medium-size and large screens, The main requirement~ which such projection apparatu-ses should ~ati~fy are high re~olution, contrast and ll~m; n~nce of the image reproduced on the screen, which image should be suitable for convenient obser-vation under given ambient illumination conditions.
Furthermore, such projection apparatuses should sa-tisfy a number of operational requirements, in parti-- cular: the power consumed by the light source of the projection apparatus should be low, the apparatus should operate in a normal electric and temperature mode, the level o~ X-ray radiation should not e~ceed permis~ible values (for projection apparatuse~ in which a picture tube is used as the image source) etc.
Television projection systems, i.e. projection apparatuses in ~hich a piGture tube is u~ed as the source of the optical ima~e, are the most widely u~ed ~ystem~, Such a televi~ion sy~tem (V.S. Babenko, rrOptics of television apparatùses", 1982, Radio i Svyaz, Moscow, p, 232-234) comprises a picture tube and projection lens objective with the screen of the picture tube positioned in the field of view thereof. In such a televi~ion projection system the illuminable image formed on the screen of the pic-,,~
. .
-- 2 --ture tube i~ projected through the projection ob-jective:onto a viewing screen ~ e luminou~ efficiency of ~uch a projection ~ystem, determin;n~ the llJm;nnnce, contra~t and co-lor ~aturation of the projected image, i8 low. Thisi~ primarily due to the fact that when the project-ion i~ made from an origi~al, the area of which i~
comparable with the area of the entrance pupil of the projection objective, only up to 9% of the lu-minous flu~, diffu~ively radiated by the original(picture tube screen), passe~ through the project-ion lens objective to the viewing ~creen, thi~
being due to the low geomjetrical-lens aperture in known projectors. An increase in the luminou~ eff-ciency of the projection ~ystem obtained by increa-~ing the area of the original without increa~ing the area of the entrance pupil of the projection len~ obàective i~ not e~fective because of the in-crease in the vi~ible difference between the lumi-nance in the center and at the edge~ of the project-ion field on the viewing ~creen and becau~e of the appearance of vi~ible geometrical aberration~. It i~
not ~easible to increase the luminous efficiency o~
the projection sy~tem by increa~ing the area of the entrance pupil of the objective without increa~ing the area of the original, either, since thi~ re-sults in the necessity to increa~e the di~tance between the objective and the original in order-to 1 prevent geometrical aberrations, which in turn re~ult~ in a reduction of the useful luminous flux in proportion to the square of the distance between the objective and the original. ~urthermore, manu-facturing projection objectives having a large ~ize entrance pupil i~ a complex proces~ from the engi-neering point of view~ The ll1min~nce of the projec-ted image i~ u~ually increa~ed in televi~ion pro-jection ~y~tem~ by operating the picture tube in forced electric and ~qevere temperature mode~. However, thi~ re~qult~q in a ~harp reduction of the ~ervice life of the picture tube, an increa~e in the X-ray radiat-ion and a reduction of thb re~olving power o~ the picture tube, Mirror-len~ television projection sy~tems, so-ca-lled Schmidt ~ystem~, are al~o known (V.S. ~abenko, "Optic~ of televi~ion applaratu~es", 1982, Radio i Svyaz, Mo~cow, p, 234-237). The~e ~y~tem~ comprise a picture tube, a concave ~pherical mirror and a cor-rection len~, all having a common optic axi~q, The concave ~pherical mirror ,together with the correct-ion len~ form~q a mirror-len~ projection objective, The ~pherical mirror i9 mounted with it~ concave ~urface facing the screen of the picture tube, the correction lens i~ di~posed behind the picture tube, The diffu~ed luminou3 ~lux from the ~creen of the picture tube, reflected ~rom the-mirror, iq focu~ed by the correction len~ onto the viewing ~creen, Such mirror-len~ televi~ion projection sy~tem~
have an optical tran~mission factor of up to 30%, ,which i~ higher than with the aforementioned projec-tion ~y~tem with a len~ objective, ~hi~ is due to the fact that a mirror-len~ objective ha~ a large angle of view and high re~olving power, The diameter of the ~pherical mirror i9 ~elec-ted on the ba~i~ of more comple2 u~e of the lumi-- nou~ flu~ radiated by the picture tube, in practice the diameter of the ~pherical mirror is selected to be from 3 to 4 time~ the-diameter of the picture tube ~creen, The radiu~ of curvature of the mirror ~nd the diameter of the correction lens are ~elec-ted on the ba~i~ of the conditions for obt~;n;n~
, the m~mum relative aperture and permiq~ible vig-netting, Wherein, the radiu~ of curvature of themirror-i~ ~elected to be from 0,8 to 1,0 the dia-'~ .
meter of the mirror, while the diameter of the cor-rection len~ elected to be from 0.65 to 0.75 the diameter of the mirror. These ratio~ ~how that for small picture tube ~creen ~izes the mirror and correc-tion lens are large. The use of picture tube~ having~mall ~creen sizes limits the luminou~ efficiency of the projection ~y~tem ~or average and large viewing ~creen~; in other words, the attainment of high lu-m~n~nce~ contrast and color ~aturation of the projec-1b ted image on medium-size and large screen~ i~ not po~sible with ~mall ~ize picture tube ~creen~. But an increa~e in picture tube screen ~ize brings about a ~ub~tantial increa~e in the dimen~ions o~ the ~phe-rical mirror and correction lens, i.e. an increa~e in the ~ize of the projection ~y~tem, which makes ma-nufacturing and alignment of the projection sy~tem more complex.
A projection apparatus i~ al~o known (US ~o.
3506782) compri~ing a fiber-optical plate, the ent-rance face~ of the light guide~ of which coincidewith the plane of the original image, and a project-ion objective, with the exit face~ of the light guide~ of the ~iber-optical plate po~itioned in the field of view of that objective. A picture tube with ultraviolet diffu~ive light radiation i~ u~ed in thi~ projection apparatu~ a~ the primary modula-tor of the original image, a dichroic filter being po~itioned on the screen thereof to reflect vi~ible beam~ and pa~ ultraviolet ray~. ~he ~aid fiber-op-3o tical plate is mounted on the dichroic filter, theplate having photochrome light guide~, the tran~pa-rency o~ which change~ depending on the ll~m;n~nce of the ultraviolet light. Thu~, the photochrome light guide~ are a physically active optical medium, ~ub~tantially a ~econdar-~ spacellight modulator of the original image, for the visible light pa~ing therethrough and forming the original image. ~urther-more, the projection apparatus comprises a first op-tical sy~tem, formed by a first mirror and collecti-ve len~, for directing visible light from a point source of light through the light guides of the fiber-optical plate to the dichroic filter, and a se-cond optical ~ystem, formed by the said collective lens, a second mirror and a lens objective for mag-nifying the image projected on the viewing screen, for projecting the image reflected by the dichroic filter.
During the sc~nn;ng of the~picture tube phosphor ~creen with the electron beam, the phosphor glows with an ultraviolet light, v~hich passe~ through the dichroic filter to the photochrome light guides, the transparency of which decrea~es as the l~m;n~nce of the ultraviolet light increases. ~herein, the light rays from the poin-t ~ource o~ visible light, directed by the firqt mirror and collective lens along the optical axes of the light guide~? impinge on the dichroic filter and reflecting therefrom pa~
along the optical axes of the light guides through the said collective lens and second mirror into the entrance pupil of the projection objective. By chan-ging the l~m;n~nce of the ultraviolet light, ele-ment-by-element of the p~imary image of the origi-n&l on the picture tube screen, a change in the tran~parency of the light guides takes place, as a result of which a secondary image of the original is fo~med element-by-element by the rays of visible light within the space of the exit faces of the light guide~, which secondary image i~ projected by the objective to the viewing ~creen ~n advantage of this projection apparatus i~
increased contrast and a high optical transmission factor of the projected images. This is due to the ;~
3 7 ~
fact that the projected image of the original is formed by a directed ligh~ source.
I However, it is generally known that photochrome materials, from which the light guides of the fiber--optical plate are made, ensure the formation of image~ with a thin linear range of half-tone grada-tion~, which cau~es half-tone and color distortions in the proaected image as compared with the origi-nal image, Furthermore, due to their physical-che-mical properties, photochrome material~ have a limi-ted cyclicity, ,which lowers the operating service life of the projection apparatus in the ca~e pf dy-namic di~play of information. The ;dependence of the speed and quality of the dynamic display of informat-ion on the power of the modulating light (in thi~
case on the power of the ultraviolet light) limits the frequency of image frame change of the original on the screen of the display in the projection appa-ratu~, The use of light guides made of photochrome ma-terial~limit~ the field of usage of such projection apparatus, since photochrome light guides only chan-ge their transparency due to the effect of ultravio-let light; in other words such a projection appara-tus i~ capable of projecting the image of originals radiating ultraviolet light.
The presence of a fir~t optical ~ystem with an e~ternal point source of visible light, the use of photochrome light guide~ and dichroic filters make ' the con~truction of the projection apparatu~ more ' complex.
Furthermore, the use of an external source of visible light re~ults in an increase in the power con~umed by the projection apparatu~.
: - 7 -Object~ and Summary o~ the Invention ~ he ob~ect of the invention i~ to create a pro-jection apparatus in which the con~tructive realizat-ion of the light guide~ of a fiber-optical plate would en~ure high quality'of projected color and mono-chrome image~ of the original during lengthy operat-ion of the proje.ction apparatu~, ~implification of it~ construction and reduction of the power con~ump-tion.
This problem i~ ~olved in that in a projection apparatu~ comprising a fiber-optical plate, the en-trance faceq of the light guide~ of which coincide with the plane of the original image, and a project-ion len~j the e~it face~ of the light guide~ of the fiber-optical plate being di~po~ed in the field of view thereof, in accordance with the invention, an optical syqtem is formed in each of the light guide~
of the fiber-optical plate in the path of propagat-ion of the light beams to concentrate the light ray~
into a light beam and direct that light beam into the entrance pupil of the projection objective. .
The optical ~yqtem formed in each of the light guideq of the fiber-optical plate to concentrate .:
the light ray~ into a light beam and direct that light beam into the entrance pupil of the objective i~ physically pa~ive optical m.edium for light ray~ -and only en~ure~ optical-geometrical tran~formation of the primary image of the original u~ing optical elements having con~tant light tran~mi~sion, refrac-tion and reflection factor~. Thi~ in turn en~ure~the preservation of the width of the half-tone gra-dation range, the color qaturation and color purity in the projected image during lengthy ~ervice time of the pro;ection apparatu~, independent of the fre-quency and cyclicity of image frame change in the .' ~, .
_ 8 --- original. Concentration of, the luminous flu~, radia-ted by the original, in the entrance pupil of the projection objective ensure~ an increase in the lumi-nance oflthe projected image on the viewing screen without increasing the power consumed by the project-ion apparatus. The realization of optical sy~tems in the light guides of the fiber-optical plate ensures simplification of the construction and size reduction.
~urthermore, such a projection apparatus is capable of projecting any type of original image over the whole band of the optical spectrum pa~sed by the light guides of the fiber-optical plate.
Embodiments of the constructive realization of optical systems for concentrating light rays into a light beam and directing that light beam into the entrance pupil of the objective are possible.,In the case when the optical axes of the light guide~ are parallel to the optical axis of the projection ob-jective a~d do not pass through its entrance pupil, then it is feasible that the optical system be for-med by a focon, positive lens and refracting prism positioned ~uccessively in the path of the light rays in the light guide, ~Jhile the common optical agis of the focon and positive lens be made to coin-cide with the optical axis of the light guide. Theconstruction of the refracting prism and its orient-ation in a separate light guide relative to the entrance pupil of the objective ensuring the trans-mission of a maximum luminous flu~ through the en-trance pupil of the len~, is determined by wellknown calculations according to known methods.
In the case when the optical axes of the light guides of the fiber-optical plate are directed to the entrance pupil of the! len~, then it is feasible that the optical system be formed by positioning the focon and positive lens ~uccessively along the ,r h .
path of the light ray~ in the light guide, while the common optical axi~ thereof wo~ld coincide with the optical axi~ of the light guide and be directed to the entrance pupil of the projection objective. In that ca~e deflection of the light ray.~ i~ en~ured by orientation of the light guides relative to the ent-rance pupil of the projection objective.
, Brief Description of the Drawing~
The advantages of the invention become easier to under~tand from the following concrete e2ample~
- of realization thereof and drawing~ wherein:
Figure 1 ~how~ the ~chematic diagram of the projection apparatu~ made in a televi~ion proaect-ion sy~tem in accordance with the invention;
Figure 2 shows the out~ide element A in Figu-re 1;
~ igure 3 ~how~ the schematic diagram of the pro-jection apparatu~ made in a television projection sy~tem in accordance with the invention, second em-bodiment;
~ igure 4 ~how~ the out~ide element B in Figu-re 3.
Description of the Preferred Embodiments Consideration will be given to the fir~t embodi-ment of a televi~ion apparatus made in accordance with the invention and serving to project the image of an original from the ~creen of a television pic-ture tube. Thi~ projecti~n apparatu~ comprises a fiber-optical plate 1 (Figure 1), the entrance face~ 2 of the light guide~ 3 of which coincide with plane a-a of the image of the original. In other words, the fiber-optical plate 1 with entran-ce face~ 2 of it~ light guides i~ positioned onthe ~creen 4 of a televi~ion picture tube 5. The - 10 _ screen 4 of the picture tube 5 i8 formed by a phos-phor layer 6 (~igure 2), applied to the entrance faces 2 of the light guides 3 and covered with a light reflecting film 7 made of aluminum. ~urther-more, the projection apparatus comprises a project-ion objective 8 (Figure 1), the exit faces 9 of the light guides 3 being positioned in the field of view thereof. The optical axes ~1-~1 of light quide~
3 are parallel to the optical axis ~2-~2 of the pro-jection objective 8. An optical syqtem 10 (Figure 2)iq formed in each of the light guide~ 3 of the fiber-optical plate 1 in the path of propagation of the light rays, conditionally designated in the drawing by arrows, to concentrate the light rays into a light beam and direct that light beam to the entrance pupil 11 (~igure 1) of the projection objective 8. The optical system 10 is formed by a focon ~2 (~igure 2), crescent-shaped positive lens 13 and refracting prism 14, successively dispo-sed along the path of the light rays in the lightguide. Wherein, the optical axes 03-03, 04-04 of the facon 12 and crescent-shaped positive lens 13 concide with the optical axis ~1-~1 of the light guide 3. Each of the light guides 3 is made in a shell 15, the inner surfaces of vrhich are covered with a light reflecting layer 16, in this case a iayer of aluminum.
The described proje¢tion apparatus operates in the following m~nner. During scanning of the screen 4 of the picture tube 5 with the electron ray, element-by-element illumination of the phosphor layer 6 takeq place with diffused light. ~he diffu-sed light passes through the focon 12, the cre~cent-shaped positive,lens 13 and refracting prism 14.
The focon 12 concentrates the diffused light in its exit face. The crescent-shaped positive lens 13 i -1 transform~ the diverging wide light beam exiting from the focon 12 into a diverging narrow light beam.
Concentration of the light rays into a light beam is en~ured this way. After that the reflecting pri~m 14 deflects the light beam to the entrance pupil 11 of the projection objective 8.
One more embodiment of the projection apparatus will now be given consideration. The distinction between this projection apparatus and the apparatus described in the first embodiment is that the opti-cal ~xes ~1-~1 (Figure 3) of the light guides 3 are directed to the entrance pupil 11 of the projection objective 8. This serve~ to simplify the construct-ion of the optical system llO(Figure 4) for concent-rating the light rays into a light beam and direct-ing that light beam to the entrance pupil 11 of the projection objective 8. This optical systemllO is formed b~ positioning a focon 17 and crescent-shaped positive lens 18 succes~ively along the path of the light rayb in the light guide 3, the optical axes ~5~~5~ ~6-~6 of which coincide with the optical agis ~1-~1 of the li~ht guide 3 and are directed to the entrance pupil 11 of the projection objective 8.
This projection apparatu~ operates in a manner similar to the projection apparatus described in the first embodiment. The distinction is that the light beam concentrated by the focon 17 and positive crescent-shaped len~ 18 i~ directed to the entrance pupil 11 of the projection objective 8 directly.
Industrial Use The projection apparatuses made in accordance with the invention are most effectively used in tele-vision projection systems, projection displays, pro-jection indicators and epidiascope~. These project-ion apparatu~es ensure high luminouq efficiency, exceeding 50~0, with uniform ll~m;n~nce at the edges and in the center of the field of the projected image~
~urthermore, such a projection apparatus makes it possible to increase the l~m;n~nce of the projected image for a constant size of the entrance pupil of the projection objective due to the increase in the size of the image of the original with a high lumi-nous efficiency, which makes it possible to increase the resolving power of the projection apparatus.
~, .
~ield of the Invention ~hi~ invention relates to optical instrument building, to apparatuses ~or projecting the display of yisual information, more specifically - to projec-tion apparatus.
Description of the Prior Art At the present time work i~ being conducted with the aim of improving ~nown and creating ba~ically new con~tructions of small-size projection apparatuses, which would make it possible to obtain a high quality reproduced image on medium-size and large screens, The main requirement~ which such projection apparatu-ses should ~ati~fy are high re~olution, contrast and ll~m; n~nce of the image reproduced on the screen, which image should be suitable for convenient obser-vation under given ambient illumination conditions.
Furthermore, such projection apparatuses should sa-tisfy a number of operational requirements, in parti-- cular: the power consumed by the light source of the projection apparatus should be low, the apparatus should operate in a normal electric and temperature mode, the level o~ X-ray radiation should not e~ceed permis~ible values (for projection apparatuse~ in which a picture tube is used as the image source) etc.
Television projection systems, i.e. projection apparatuses in ~hich a piGture tube is u~ed as the source of the optical ima~e, are the most widely u~ed ~ystem~, Such a televi~ion sy~tem (V.S. Babenko, rrOptics of television apparatùses", 1982, Radio i Svyaz, Moscow, p, 232-234) comprises a picture tube and projection lens objective with the screen of the picture tube positioned in the field of view thereof. In such a televi~ion projection system the illuminable image formed on the screen of the pic-,,~
. .
-- 2 --ture tube i~ projected through the projection ob-jective:onto a viewing screen ~ e luminou~ efficiency of ~uch a projection ~ystem, determin;n~ the llJm;nnnce, contra~t and co-lor ~aturation of the projected image, i8 low. Thisi~ primarily due to the fact that when the project-ion i~ made from an origi~al, the area of which i~
comparable with the area of the entrance pupil of the projection objective, only up to 9% of the lu-minous flu~, diffu~ively radiated by the original(picture tube screen), passe~ through the project-ion lens objective to the viewing ~creen, thi~
being due to the low geomjetrical-lens aperture in known projectors. An increase in the luminou~ eff-ciency of the projection ~ystem obtained by increa-~ing the area of the original without increa~ing the area of the entrance pupil of the projection len~ obàective i~ not e~fective because of the in-crease in the vi~ible difference between the lumi-nance in the center and at the edge~ of the project-ion field on the viewing ~creen and becau~e of the appearance of vi~ible geometrical aberration~. It i~
not ~easible to increase the luminous efficiency o~
the projection sy~tem by increa~ing the area of the entrance pupil of the objective without increa~ing the area of the original, either, since thi~ re-sults in the necessity to increa~e the di~tance between the objective and the original in order-to 1 prevent geometrical aberrations, which in turn re~ult~ in a reduction of the useful luminous flux in proportion to the square of the distance between the objective and the original. ~urthermore, manu-facturing projection objectives having a large ~ize entrance pupil i~ a complex proces~ from the engi-neering point of view~ The ll1min~nce of the projec-ted image i~ u~ually increa~ed in televi~ion pro-jection ~y~tem~ by operating the picture tube in forced electric and ~qevere temperature mode~. However, thi~ re~qult~q in a ~harp reduction of the ~ervice life of the picture tube, an increa~e in the X-ray radiat-ion and a reduction of thb re~olving power o~ the picture tube, Mirror-len~ television projection sy~tems, so-ca-lled Schmidt ~ystem~, are al~o known (V.S. ~abenko, "Optic~ of televi~ion applaratu~es", 1982, Radio i Svyaz, Mo~cow, p, 234-237). The~e ~y~tem~ comprise a picture tube, a concave ~pherical mirror and a cor-rection len~, all having a common optic axi~q, The concave ~pherical mirror ,together with the correct-ion len~ form~q a mirror-len~ projection objective, The ~pherical mirror i9 mounted with it~ concave ~urface facing the screen of the picture tube, the correction lens i~ di~posed behind the picture tube, The diffu~ed luminou3 ~lux from the ~creen of the picture tube, reflected ~rom the-mirror, iq focu~ed by the correction len~ onto the viewing ~creen, Such mirror-len~ televi~ion projection sy~tem~
have an optical tran~mission factor of up to 30%, ,which i~ higher than with the aforementioned projec-tion ~y~tem with a len~ objective, ~hi~ is due to the fact that a mirror-len~ objective ha~ a large angle of view and high re~olving power, The diameter of the ~pherical mirror i9 ~elec-ted on the ba~i~ of more comple2 u~e of the lumi-- nou~ flu~ radiated by the picture tube, in practice the diameter of the ~pherical mirror is selected to be from 3 to 4 time~ the-diameter of the picture tube ~creen, The radiu~ of curvature of the mirror ~nd the diameter of the correction lens are ~elec-ted on the ba~i~ of the conditions for obt~;n;n~
, the m~mum relative aperture and permiq~ible vig-netting, Wherein, the radiu~ of curvature of themirror-i~ ~elected to be from 0,8 to 1,0 the dia-'~ .
meter of the mirror, while the diameter of the cor-rection len~ elected to be from 0.65 to 0.75 the diameter of the mirror. These ratio~ ~how that for small picture tube ~creen ~izes the mirror and correc-tion lens are large. The use of picture tube~ having~mall ~creen sizes limits the luminou~ efficiency of the projection ~y~tem ~or average and large viewing ~creen~; in other words, the attainment of high lu-m~n~nce~ contrast and color ~aturation of the projec-1b ted image on medium-size and large screen~ i~ not po~sible with ~mall ~ize picture tube ~creen~. But an increa~e in picture tube screen ~ize brings about a ~ub~tantial increa~e in the dimen~ions o~ the ~phe-rical mirror and correction lens, i.e. an increa~e in the ~ize of the projection ~y~tem, which makes ma-nufacturing and alignment of the projection sy~tem more complex.
A projection apparatus i~ al~o known (US ~o.
3506782) compri~ing a fiber-optical plate, the ent-rance face~ of the light guide~ of which coincidewith the plane of the original image, and a project-ion objective, with the exit face~ of the light guide~ of the ~iber-optical plate po~itioned in the field of view of that objective. A picture tube with ultraviolet diffu~ive light radiation i~ u~ed in thi~ projection apparatu~ a~ the primary modula-tor of the original image, a dichroic filter being po~itioned on the screen thereof to reflect vi~ible beam~ and pa~ ultraviolet ray~. ~he ~aid fiber-op-3o tical plate is mounted on the dichroic filter, theplate having photochrome light guide~, the tran~pa-rency o~ which change~ depending on the ll~m;n~nce of the ultraviolet light. Thu~, the photochrome light guide~ are a physically active optical medium, ~ub~tantially a ~econdar-~ spacellight modulator of the original image, for the visible light pa~ing therethrough and forming the original image. ~urther-more, the projection apparatus comprises a first op-tical sy~tem, formed by a first mirror and collecti-ve len~, for directing visible light from a point source of light through the light guides of the fiber-optical plate to the dichroic filter, and a se-cond optical ~ystem, formed by the said collective lens, a second mirror and a lens objective for mag-nifying the image projected on the viewing screen, for projecting the image reflected by the dichroic filter.
During the sc~nn;ng of the~picture tube phosphor ~creen with the electron beam, the phosphor glows with an ultraviolet light, v~hich passe~ through the dichroic filter to the photochrome light guides, the transparency of which decrea~es as the l~m;n~nce of the ultraviolet light increases. ~herein, the light rays from the poin-t ~ource o~ visible light, directed by the firqt mirror and collective lens along the optical axes of the light guide~? impinge on the dichroic filter and reflecting therefrom pa~
along the optical axes of the light guides through the said collective lens and second mirror into the entrance pupil of the projection objective. By chan-ging the l~m;n~nce of the ultraviolet light, ele-ment-by-element of the p~imary image of the origi-n&l on the picture tube screen, a change in the tran~parency of the light guides takes place, as a result of which a secondary image of the original is fo~med element-by-element by the rays of visible light within the space of the exit faces of the light guide~, which secondary image i~ projected by the objective to the viewing ~creen ~n advantage of this projection apparatus i~
increased contrast and a high optical transmission factor of the projected images. This is due to the ;~
3 7 ~
fact that the projected image of the original is formed by a directed ligh~ source.
I However, it is generally known that photochrome materials, from which the light guides of the fiber--optical plate are made, ensure the formation of image~ with a thin linear range of half-tone grada-tion~, which cau~es half-tone and color distortions in the proaected image as compared with the origi-nal image, Furthermore, due to their physical-che-mical properties, photochrome material~ have a limi-ted cyclicity, ,which lowers the operating service life of the projection apparatus in the ca~e pf dy-namic di~play of information. The ;dependence of the speed and quality of the dynamic display of informat-ion on the power of the modulating light (in thi~
case on the power of the ultraviolet light) limits the frequency of image frame change of the original on the screen of the display in the projection appa-ratu~, The use of light guides made of photochrome ma-terial~limit~ the field of usage of such projection apparatus, since photochrome light guides only chan-ge their transparency due to the effect of ultravio-let light; in other words such a projection appara-tus i~ capable of projecting the image of originals radiating ultraviolet light.
The presence of a fir~t optical ~ystem with an e~ternal point source of visible light, the use of photochrome light guide~ and dichroic filters make ' the con~truction of the projection apparatu~ more ' complex.
Furthermore, the use of an external source of visible light re~ults in an increase in the power con~umed by the projection apparatu~.
: - 7 -Object~ and Summary o~ the Invention ~ he ob~ect of the invention i~ to create a pro-jection apparatus in which the con~tructive realizat-ion of the light guide~ of a fiber-optical plate would en~ure high quality'of projected color and mono-chrome image~ of the original during lengthy operat-ion of the proje.ction apparatu~, ~implification of it~ construction and reduction of the power con~ump-tion.
This problem i~ ~olved in that in a projection apparatu~ comprising a fiber-optical plate, the en-trance faceq of the light guide~ of which coincide with the plane of the original image, and a project-ion len~j the e~it face~ of the light guide~ of the fiber-optical plate being di~po~ed in the field of view thereof, in accordance with the invention, an optical syqtem is formed in each of the light guide~
of the fiber-optical plate in the path of propagat-ion of the light beams to concentrate the light ray~
into a light beam and direct that light beam into the entrance pupil of the projection objective. .
The optical ~yqtem formed in each of the light guideq of the fiber-optical plate to concentrate .:
the light ray~ into a light beam and direct that light beam into the entrance pupil of the objective i~ physically pa~ive optical m.edium for light ray~ -and only en~ure~ optical-geometrical tran~formation of the primary image of the original u~ing optical elements having con~tant light tran~mi~sion, refrac-tion and reflection factor~. Thi~ in turn en~ure~the preservation of the width of the half-tone gra-dation range, the color qaturation and color purity in the projected image during lengthy ~ervice time of the pro;ection apparatu~, independent of the fre-quency and cyclicity of image frame change in the .' ~, .
_ 8 --- original. Concentration of, the luminous flu~, radia-ted by the original, in the entrance pupil of the projection objective ensure~ an increase in the lumi-nance oflthe projected image on the viewing screen without increasing the power consumed by the project-ion apparatus. The realization of optical sy~tems in the light guides of the fiber-optical plate ensures simplification of the construction and size reduction.
~urthermore, such a projection apparatus is capable of projecting any type of original image over the whole band of the optical spectrum pa~sed by the light guides of the fiber-optical plate.
Embodiments of the constructive realization of optical systems for concentrating light rays into a light beam and directing that light beam into the entrance pupil of the objective are possible.,In the case when the optical axes of the light guide~ are parallel to the optical axis of the projection ob-jective a~d do not pass through its entrance pupil, then it is feasible that the optical system be for-med by a focon, positive lens and refracting prism positioned ~uccessively in the path of the light rays in the light guide, ~Jhile the common optical agis of the focon and positive lens be made to coin-cide with the optical axis of the light guide. Theconstruction of the refracting prism and its orient-ation in a separate light guide relative to the entrance pupil of the objective ensuring the trans-mission of a maximum luminous flu~ through the en-trance pupil of the len~, is determined by wellknown calculations according to known methods.
In the case when the optical axes of the light guides of the fiber-optical plate are directed to the entrance pupil of the! len~, then it is feasible that the optical system be formed by positioning the focon and positive lens ~uccessively along the ,r h .
path of the light ray~ in the light guide, while the common optical axi~ thereof wo~ld coincide with the optical axi~ of the light guide and be directed to the entrance pupil of the projection objective. In that ca~e deflection of the light ray.~ i~ en~ured by orientation of the light guides relative to the ent-rance pupil of the projection objective.
, Brief Description of the Drawing~
The advantages of the invention become easier to under~tand from the following concrete e2ample~
- of realization thereof and drawing~ wherein:
Figure 1 ~how~ the ~chematic diagram of the projection apparatu~ made in a televi~ion proaect-ion sy~tem in accordance with the invention;
Figure 2 shows the out~ide element A in Figu-re 1;
~ igure 3 ~how~ the schematic diagram of the pro-jection apparatu~ made in a television projection sy~tem in accordance with the invention, second em-bodiment;
~ igure 4 ~how~ the out~ide element B in Figu-re 3.
Description of the Preferred Embodiments Consideration will be given to the fir~t embodi-ment of a televi~ion apparatus made in accordance with the invention and serving to project the image of an original from the ~creen of a television pic-ture tube. Thi~ projecti~n apparatu~ comprises a fiber-optical plate 1 (Figure 1), the entrance face~ 2 of the light guide~ 3 of which coincide with plane a-a of the image of the original. In other words, the fiber-optical plate 1 with entran-ce face~ 2 of it~ light guides i~ positioned onthe ~creen 4 of a televi~ion picture tube 5. The - 10 _ screen 4 of the picture tube 5 i8 formed by a phos-phor layer 6 (~igure 2), applied to the entrance faces 2 of the light guides 3 and covered with a light reflecting film 7 made of aluminum. ~urther-more, the projection apparatus comprises a project-ion objective 8 (Figure 1), the exit faces 9 of the light guides 3 being positioned in the field of view thereof. The optical axes ~1-~1 of light quide~
3 are parallel to the optical axis ~2-~2 of the pro-jection objective 8. An optical syqtem 10 (Figure 2)iq formed in each of the light guide~ 3 of the fiber-optical plate 1 in the path of propagation of the light rays, conditionally designated in the drawing by arrows, to concentrate the light rays into a light beam and direct that light beam to the entrance pupil 11 (~igure 1) of the projection objective 8. The optical system 10 is formed by a focon ~2 (~igure 2), crescent-shaped positive lens 13 and refracting prism 14, successively dispo-sed along the path of the light rays in the lightguide. Wherein, the optical axes 03-03, 04-04 of the facon 12 and crescent-shaped positive lens 13 concide with the optical axis ~1-~1 of the light guide 3. Each of the light guides 3 is made in a shell 15, the inner surfaces of vrhich are covered with a light reflecting layer 16, in this case a iayer of aluminum.
The described proje¢tion apparatus operates in the following m~nner. During scanning of the screen 4 of the picture tube 5 with the electron ray, element-by-element illumination of the phosphor layer 6 takeq place with diffused light. ~he diffu-sed light passes through the focon 12, the cre~cent-shaped positive,lens 13 and refracting prism 14.
The focon 12 concentrates the diffused light in its exit face. The crescent-shaped positive lens 13 i -1 transform~ the diverging wide light beam exiting from the focon 12 into a diverging narrow light beam.
Concentration of the light rays into a light beam is en~ured this way. After that the reflecting pri~m 14 deflects the light beam to the entrance pupil 11 of the projection objective 8.
One more embodiment of the projection apparatus will now be given consideration. The distinction between this projection apparatus and the apparatus described in the first embodiment is that the opti-cal ~xes ~1-~1 (Figure 3) of the light guides 3 are directed to the entrance pupil 11 of the projection objective 8. This serve~ to simplify the construct-ion of the optical system llO(Figure 4) for concent-rating the light rays into a light beam and direct-ing that light beam to the entrance pupil 11 of the projection objective 8. This optical systemllO is formed b~ positioning a focon 17 and crescent-shaped positive lens 18 succes~ively along the path of the light rayb in the light guide 3, the optical axes ~5~~5~ ~6-~6 of which coincide with the optical agis ~1-~1 of the li~ht guide 3 and are directed to the entrance pupil 11 of the projection objective 8.
This projection apparatu~ operates in a manner similar to the projection apparatus described in the first embodiment. The distinction is that the light beam concentrated by the focon 17 and positive crescent-shaped len~ 18 i~ directed to the entrance pupil 11 of the projection objective 8 directly.
Industrial Use The projection apparatuses made in accordance with the invention are most effectively used in tele-vision projection systems, projection displays, pro-jection indicators and epidiascope~. These project-ion apparatu~es ensure high luminouq efficiency, exceeding 50~0, with uniform ll~m;n~nce at the edges and in the center of the field of the projected image~
~urthermore, such a projection apparatus makes it possible to increase the l~m;n~nce of the projected image for a constant size of the entrance pupil of the projection objective due to the increase in the size of the image of the original with a high lumi-nous efficiency, which makes it possible to increase the resolving power of the projection apparatus.
~, .
Claims (3)
1. A projection apparatus comprising a fiber-optical plate (1), entrance faces (2) of light guides (3) which coincide with a plane (a-a) of an image of an original, and a projection objective (8), exit faces (9) of the light guides (3) of the fiber-optical plate (1) being disposed in a field of view thereof, characterized in that an optical system (10) for concentrating light rays into a light beam and directing said light beam into an entrance pupil (11) of the projection objective (8) is formed in each of the light guides (3) of the fiber-optical plate (1) along the path of propagation of the light rays.
2. A projection apparatus according to claim 1, characterized in that an optical system (10) is formed by a focon (12), positive lens (13) and refracting prism (14) disposed successively in the light guide (3) along a path of the light rays, and an optical axis (O3-O3) of the focon (12) and an optical axis (O4-O4) of the positive lens (13) coincide with an optical axis (O1-O1) of the light guide (3).
3. A projection apparatus according to claim 1, characterized in that the optical system (10) is formed by a focon (17) and positive lens (18) disposed successively in the light guide (3) along the path of the light rays, while an optical axis (O5-O5) of the focon (17) and an optical axis (O6-O6) of the positive lens (18) coincide with the optical axis (O1-O1) of the light guide (3) and are directed to the entrance pupil (11) of the projection objective (8).
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| SU904842730A RU2027316C1 (en) | 1990-06-29 | 1990-06-29 | Projector of images from diffusion-emitting or radiating master patterns to external screen |
| SU4842730/10 | 1990-06-29 | ||
| PCT/SU1991/000131 WO1992000551A1 (en) | 1990-06-29 | 1991-06-28 | Projector |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2065376A1 CA2065376A1 (en) | 1991-12-30 |
| CA2065376C true CA2065376C (en) | 1999-06-08 |
Family
ID=21522852
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002065376A Expired - Fee Related CA2065376C (en) | 1990-06-29 | 1991-06-28 | Projection apparatus |
Country Status (11)
| Country | Link |
|---|---|
| EP (1) | EP0491963A4 (en) |
| JP (1) | JP2903485B2 (en) |
| KR (1) | KR0176976B1 (en) |
| AU (1) | AU676133B2 (en) |
| BR (1) | BR9105808A (en) |
| CA (1) | CA2065376C (en) |
| FI (1) | FI920909A0 (en) |
| HU (2) | HUT62099A (en) |
| NO (1) | NO920795L (en) |
| RU (1) | RU2027316C1 (en) |
| WO (1) | WO1992000551A1 (en) |
Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| AU4696996A (en) * | 1995-01-12 | 1996-07-31 | Allied-Signal Inc. | Display screen device with array of tapered waveguides |
| RU2126986C1 (en) * | 1997-11-24 | 1999-02-27 | АРСЕНИЧ Святослав Иванович | Optical raster condenser and optical article with raster condenser |
| US6317545B1 (en) * | 1999-09-01 | 2001-11-13 | James T. Veligdan | Stepped inlet optical panel |
| US7001058B2 (en) * | 2001-05-16 | 2006-02-21 | Ben-Zion Inditsky | Ultra-thin backlight |
| US8684584B2 (en) | 2001-05-16 | 2014-04-01 | Benzion Inditsky | Ultra-thin backlight |
| JP5822502B2 (en) | 2011-03-29 | 2015-11-24 | 三菱重工業株式会社 | Spacecraft |
Family Cites Families (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5126074B2 (en) * | 1971-12-29 | 1976-08-04 | ||
| US3951533A (en) * | 1974-09-20 | 1976-04-20 | Xerox Corporation | Color image reproduction system |
| JPS51129125A (en) * | 1975-05-02 | 1976-11-10 | Maruko Kaihatsu Kenkyusho:Kk | Braun tube image induction reproduction device |
| JPS5338222A (en) * | 1976-09-20 | 1978-04-08 | Sanyo Electric Co Ltd | Braun tube for projection television |
| JPS579187A (en) * | 1980-06-20 | 1982-01-18 | Hitachi Ltd | Dropout compensating device |
| US4601537A (en) * | 1984-01-06 | 1986-07-22 | Ohio State University Research Foundation | Apparatus and methods for forming images and for optical demultiplexing |
| US4573082A (en) * | 1984-01-16 | 1986-02-25 | Incom, Inc. | Focusable display screen |
| JPS61188509A (en) * | 1985-02-16 | 1986-08-22 | Nippon Hoso Kyokai <Nhk> | Optical coupling device |
| US4904049A (en) * | 1988-09-01 | 1990-02-27 | Hughes Aircraft Company | High-contrast fiber optic diffusion faceplate with radiused fibers |
| JPH02148534A (en) * | 1988-11-30 | 1990-06-07 | Hitachi Ltd | Projection type display |
-
1990
- 1990-06-29 RU SU904842730A patent/RU2027316C1/en active
-
1991
- 1991-06-28 EP EP19910912822 patent/EP0491963A4/en not_active Ceased
- 1991-06-28 HU HU9200911A patent/HUT62099A/en unknown
- 1991-06-28 JP JP3512059A patent/JP2903485B2/en not_active Expired - Lifetime
- 1991-06-28 KR KR1019920700465A patent/KR0176976B1/en not_active IP Right Cessation
- 1991-06-28 CA CA002065376A patent/CA2065376C/en not_active Expired - Fee Related
- 1991-06-28 BR BR919105808A patent/BR9105808A/en not_active IP Right Cessation
- 1991-06-28 WO PCT/SU1991/000131 patent/WO1992000551A1/en not_active Application Discontinuation
- 1991-06-28 AU AU82034/91A patent/AU676133B2/en not_active Ceased
-
1992
- 1992-02-28 FI FI920909A patent/FI920909A0/en unknown
- 1992-02-28 NO NO92920795A patent/NO920795L/en unknown
- 1992-03-18 HU HU9200911A patent/HU9200911D0/en unknown
Also Published As
| Publication number | Publication date |
|---|---|
| WO1992000551A1 (en) | 1992-01-09 |
| RU2027316C1 (en) | 1995-01-20 |
| CA2065376A1 (en) | 1991-12-30 |
| AU676133B2 (en) | 1997-03-06 |
| FI920909A0 (en) | 1992-02-28 |
| EP0491963A1 (en) | 1992-07-01 |
| EP0491963A4 (en) | 1993-06-02 |
| HU9200911D0 (en) | 1992-06-29 |
| KR920702508A (en) | 1992-09-04 |
| JPH06502955A (en) | 1994-03-31 |
| NO920795D0 (en) | 1992-02-28 |
| NO920795L (en) | 1992-04-21 |
| KR0176976B1 (en) | 1999-05-15 |
| AU8203491A (en) | 1992-01-23 |
| BR9105808A (en) | 1992-08-25 |
| HUT62099A (en) | 1993-03-29 |
| JP2903485B2 (en) | 1999-06-07 |
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| EEER | Examination request | ||
| MKLA | Lapsed |