Classifications

• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B5/00—Optical elements other than lenses
  • G02B5/20—Filters
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F21—LIGHTING
  • F21S—NON-PORTABLE LIGHTING DEVICES; SYSTEMS THEREOF; VEHICLE LIGHTING DEVICES SPECIALLY ADAPTED FOR VEHICLE EXTERIORS
  • F21S10/00—Lighting devices or systems producing a varying lighting effect
  • F21S10/02—Lighting devices or systems producing a varying lighting effect changing colors
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F21—LIGHTING
  • F21V—FUNCTIONAL FEATURES OR DETAILS OF LIGHTING DEVICES OR SYSTEMS THEREOF; STRUCTURAL COMBINATIONS OF LIGHTING DEVICES WITH OTHER ARTICLES, NOT OTHERWISE PROVIDED FOR
  • F21V9/00—Elements for modifying spectral properties, polarisation or intensity of the light emitted, e.g. filters
  • F21V9/40—Elements for modifying spectral properties, polarisation or intensity of the light emitted, e.g. filters with provision for controlling spectral properties, e.g. colour, or intensity

Definitions

• the invention relates to a colour filter cell to produce light of a desired colour from a light beam comprising all wave lengths of visible light, which cell includes at least one filter element with filter portions of three different basic colours.
• the colour of the light sent by projectors is still mainly changed by means of a so-called sema- phore device comprising a few light filter foils each of one colour tumable in front of a light beam co ing from the projector.
• sema- phore device comprising a few light filter foils each of one colour tumable in front of a light beam co ing from the projector.
• separate filter foils are connected to a long band, which can be coiled to and fro in front of the projector.
• Both fil- ter types are characterized in that by means of them it is possible to produce only few preselected colours in practice.
• a usable method to separate a desired spectral band from a ray of light is also offered by a so-called dichroid interference filter.
• This filter is characterized in that a wave length band transmitted through the filter changes when the light is passing in angles of different sizes through the filter foil.
• it is not possible to get very pure colour shades by means of one filter foil, and there ⁇ fore, 3-4 such foils to be turned separately are needed successively to provide a satisfactory range of colours (patent publication EP 01 40 994 and the rec ⁇ tified version US 4 602 321).
• Drawbacks of this method are also the loss of light occurring at the transmis ⁇ sion through several junctions and the rather compli ⁇ cated structure as well as the quite expensive inter ⁇ ference filters required by the method.
• this type of projector also needs some kind of a colour equalizer before the objective, because it is not possible for the light to pass fully parallel through planar filter foils and thus, rays of light passing in different directions get shades deviating from each other.
• the object of this invention is to provide a colour filter cell avoiding the drawbacks mentioned above, by means of which cell it is possible to create almost any shade by turning the cell.
• This object is reached by means of a colour filter cell of the inven- tion, characterized in that said filter portions of three different basic colours are arranged substan ⁇ tially perpendicular to each other to form an element of three colours.
• Figure 1 shows a perspective view of a three-colour element of a colour filter cell
• Figure 2 shows the colour filter cell assembled of three-colour elements vertically from the front.
• Figure 3 shows a cross-section of a colour-rectified convex cell
• Figure 4 shows a cross-section of a colour-rectified cell, the elements of which are deformed
• Figure 5 shows the colour :cell with its control de ⁇ vices connected to-the projector.
• Figure 1 shows a basic form of a three-colour element 9, in which the element is formed of square colour filter strips 1, 2 and 3 (generally red, blue; and green) placed vertically to each other.
• broken lines 4 show the ele- ment complemented to a cube. It depends on the angle in which the element is looked at, in which area pro ⁇ portion the different filter strips are seen. By vary ⁇ ing two angles of deflection independent of each other (e.g. swing angles around axles 5 and 6), it is possible to obtain an arbitrary combination of three basic colours. When such a cell is placed in a light beam, it is subjected to the effect of three different colour filter strips in a desired proportion.
• a colour filter cell 8 of Figure 2 is created by combining elements shown in Figure 1 with each other.
• the filtering effect of the cell can be ad ⁇ justed by declining the cell in the same way as a separate element.
• the cell can be de ⁇ clined e.g. by a suitable lever mechanism either manually or even by means of two electric motors.
• Figure 3 shows how in the case of a conically opening light beam 7 a deviation between colour shades arising in different points of a planar colour filter cell can be rectified by making the cell 8 convex in a suitable way.
• a deviation from colour can be entirely rectified by means of certain angles of deflection, e.g. by making the cell spherically curved, whereby no angle error at all is created in the light beam coming straight from the front.
• Figure 4 shows an alternative way to carry out a rectification of angle: instead of making the whole cell 8 curved, separate elements 9 in different points of the cell are deformed so that their projections in the direction of the light rays coming into the cell are indentical in every point of the cell in the same way as in the convex cell shown in Figure 3.
• FIG. 5 One embodiment of the three-colour filter cell is shown in principle in Figure 5.
• a filter unit consisting of a housing 11 for device, of a possible heat filtering glass 12 placed at the output aperture of the light beam, of a possible colour equalizer 13 placed at the output aperture of the light beam, of a three-colour filter cell 8 turned by means of electrically controlled motors 14, and of a possible fan 15.
• a filter cell manufactured of a lightweight and heat resistant plastic material and e.g. repeater motors to turn the cell - a light beam of any colour in a few hundredths of a second.
• the purpose of the heat glass 12 is to absorb a great part of the heat radiation from the incoming light and thus to protect the cell 8 from overheating.
• the pur ⁇ pose of the fan 15 is also mainly to cool the cell 8.
• colour equalizer 13 can be used e.g. a frosted glass plate; it may be necessary to use an equalizer, if the opening angle of the light beam coming from the filter is very large.

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• Physics & Mathematics (AREA)
• Engineering & Computer Science (AREA)
• General Engineering & Computer Science (AREA)
• Spectroscopy & Molecular Physics (AREA)
• General Physics & Mathematics (AREA)
• Optics & Photonics (AREA)
• Optical Filters (AREA)
• Optical Elements Other Than Lenses (AREA)
• Spectrometry And Color Measurement (AREA)
• Projection Apparatus (AREA)
• Mechanical Light Control Or Optical Switches (AREA)

Applications Claiming Priority (1)

Publications (1)

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ID=8556442

Family Applications (1)

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• 1988
  • 1988-02-26 WO PCT/FI1988/000030 patent/WO1989008222A1/en not_active Application Discontinuation
  • 1988-02-26 JP JP88502438A patent/JPH03502980A/ja active Pending
  • 1988-02-26 EP EP88902484A patent/EP0403470A1/de not_active Withdrawn
  • 1988-02-26 KR KR1019890701966A patent/KR900700821A/ko not_active Application Discontinuation
• 1989
  • 1989-02-26 CH CH3844/89A patent/CH675013A5/de not_active IP Right Cessation

Non-Patent Citations (1)

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