Classifications

• • 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
  • G03B21/132—Overhead projectors, i.e. capable of projecting hand-writing or drawing during action
• • 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
  • G03B21/08—Projectors or projection-type viewers; Accessories therefor affording epidiascopic projection

Definitions

• the present invention relates to an image projection and display device that can be used either as an overhead projector or as a slide projector.
• the object of the present invention is to provide a new device for displaying and projecting images by selectively switching to either of the overhead projector or 35 mm slide projector so that the inherent advantages of both devices can be used.
• a projection and display apparatus comprising a light source emitting light beams; and a projecting means for projecting said light beams towards a screen.
• the apparatus comprises a first light-path including an overhead printer sheet to be displayed on the screen; a second light-path including a slide projector film to be displayed on the screen; directing means for selectively directing said light beams towards either or both of said light-paths; control means for controlling the light beams in said light-paths; and combining means for combining the light-paths for passing the light beams to said projecting means.
• Said control means could be Liquid crystal shutters interposed in each light-path and controlled by an electric voltage to selectively prevent or allow the passage of the light beams or alternatively mechanical shields to be inserted in the light-path to prevent the passage of the light beams.
• said directing means comprises a first half-mirror dividing the light beams from the light source into two equal parts ea-eh passing through the corresponding light-path.
• said directing means and control means are said light source being arranged to be directed in two different directions by rotation thereof or offset by displacement thereof to direct the light beams into one of said first or second light-paths and thereby controlling the light beams in the relevant Light-path, or a mirror being movable between a retracted position allowing the Light beams to pass straight ahead to the first light-path, and an extended position reflecting the Light beams to the second Light-path.
• Said combining means could be a half-mirror, or alternatively a mirror which is movable between a retracted position allowing the Light beams from the first Light-path to pass to the projecting means and an extended position reflecting the light beams from the second Light-path to the projecting means.
• each Light-path is provided with imaging elements such as mirrors and Lenses in order to project the overhead printer sheet and slide projector fiLm on the screen in equal sizes or magnitudes.
• the projection and display apparatus comprises a light source 1 and a beam-projecting means comprising a Lens 3 and a mirror 4.
• the light source 1 is surrounded by a se ispherical mirror 31.
• an half-mirror 9 that splits the light path into two parts.
• the half-mirror 9 is installed at a position immediately before the Light source after a condensor Lens 8.
• the Light beams issued by the light source 1 passes along the first light-path 6 and thence through an overhead printer sheet 16, whereas the light beams passing along the second Light-path 7 goes through a slide projector film 23 before either of these beams are eventually projected against a screen (not shown) by the beam-projecting means 2.
• the first light-path 6 is provided with a Fresnel Lens 13, a transparent heat-absorbing sheet 14, a transmission-type liquid crystal shutter 15 chich is opened and closed by a voltage applied to the shutter, and said overhead projector sheet 16, said members being preceeded by a lens 11 and a mirror 12. Thence, the Light beams pass through a half-mirror 17 and reach said beam-projecting means 2 provided immediately after said half-mirror 17. Consequently, light beams passing through said first light-path 6 are controlled by said liquid crystal shutter 15 between light sourch 1 and beam-projecting means 2. Thus, onLy when said Liquid crystal shutter 15 is open, beams from light source 1 can be projected against the screen by the beam-projecting means 2 through overhead projector sheet 16.
• the second light-path 7 is provided with a lens 20, a mirror 21, a lens 22, a slide projector film 23, lenses 24 and 25, a transparent heat-absorbing sheet 26, a transmission-type liquid crystal shutter having identical construction as said Liquid crystal shutter 15, and a mirror 28.
• the second light-path 7 is provided with a mirror 29 which reflects beams from the mirror 28 towards the half-mirror 17 so that beams reflected by the half-mirror 17 can be transmitted to said beam-pro ecting means 2. Consequently, the light path between half-mirror 17 can be transmitted to said beam-projecting means 2.
• the light path between half-mirror 17 and beam-projecting means 12 is common for the first and second light paths 6 and 7. Those lenses included in the first and second light paths 6 and 7 make up the scale factor of the included image to be almost equal to each other, thus eventually allowing images to be projected against the screen for display to become almost equal in magnitude between both light-paths.
• thermoelectric sheets 14 and 26 respectively, protect transparent liquid crystal shutters-15 and 27 from heat generated by light source 1.
• the projection and display device provided with above-mentioned eLements is effectively used both as an overhead projector and a slide film projector.
• the transparent liquid crystal shutter 15 of the first light-path 6 is opened, and the transparent liquid crystal shutter 27 is closed.
• Light beams from the Light source 1 will pass through the first Light-path 6, and the image of the overhead projector sheet 16 is projected against the screen by the mirror 4 of beam-projecting means 2.
• the transparent liquid crystal shutter 15 of the first light-path 6 is closed and the transparent Liquid crystal shutter 27 of the second light-path 7 is opened.
• the condensor lens 8 may be arranged in a beam-projecting hole prepared in a part of a reflection plate 31 having spherical hollow configuration while said reflection plate totally surrounds the light source 1.
• the assembly comprising the light source 1, the reflection plate 31 and condensor lens 8 may alternatively be arranged at the position of half-mirror 9 to allow beams to be emitted through either of said light-paths 6 and 7 by rotating the assembly by 90 .
• a still further embodiment uses a specific mirror in place of half-mirror shown in Fig.
• the display and projecting device according to the present invention is also easily made up by modifying a conventional overhead projector or slide film projector available today. From the above it is evident that a projection and display apparatus for both overhead printer sheets and slide projector film has been provided. It is clear that the disclosed embodiment may be amended in many details without departing from the scope of the invention. Specifically, it is pointed out that said shutters 15, 27 both may be opened simultaneously to superpose the images of the slide projector film and the overhead printer sheet. The invention is only limited by the appended claims.

Landscapes

• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Overhead Projectors And Projection Screens (AREA)
• Projection Apparatus (AREA)
• Liquid Crystal (AREA)

Priority Applications (2)

Applications Claiming Priority (2)

Publications (1)

Family

ID=17455525

Family Applications (1)

Country Status (3)

Cited By (2)

Families Citing this family (2)

Citations (3)

Family Cites Families (1)

• 1985
  • 1985-11-28 JP JP60268216A patent/JPS62127723A/ja active Granted
• 1986
  • 1986-11-26 WO PCT/SE1986/000541 patent/WO1987003385A1/en unknown
  • 1986-11-27 ES ES8603197A patent/ES2003551A6/es not_active Expired

Patent Citations (3)

Non-Patent Citations (1)

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