GB2108703A

GB2108703A - Optical-mechanical scanning image display apparatus

Info

Publication number: GB2108703A
Application number: GB08228868A
Authority: GB
Inventors: Timothy David Joseph Stamper; Christopher Timothy Jo Stamper; John Stuart Lathbury
Original assignee: Individual
Current assignee: Individual
Priority date: 1981-10-10
Filing date: 1982-10-08
Publication date: 1983-05-18

Abstract

An image is displayed on a screen by scanning the screen horizontally and vertically with a modulated beam of light, such as laser light, in the manner in which a television picture is constructed. The vertical and horizontal scanning of the light beam may be effected by planar mirrors which are arranged to form the sides of two regular polygons (7, 10). The first polygon (7) is positioned to reflect the light beam (6) received from the laser source (5) and is rotated about its axis at a preselected speed to cause the reflected beam (9) to scan right to light beam (6) received from the laser source (5) and is rotated about its axis at a preselected speed to cause the reflected beam (9) to scan right to left or left to right in a rectilinear path at the desired speed. This reflected beam is further reflected by e.g. the polygon (10) which is also rotated about its axis arranged at 90 DEG to the axis of the first polygon (7) to provide a further reflected beam (3) which is scanned in a rectilinear path at right-angles to the scanning path of the first reflected beam (9). The apparatus enables large scale images to be produced relatively easily. <IMAGE>

Description

SPECIFICATION Improvements relating to image display apparatus The present invention relates to apparatus for displaying an image.

One of the problems associated with apparatus for displaying large scale images such as television images lies in the complexity of such apparatus and, where television tubes are concerned, the limitations placed on the sizes of the tubes.

Accordingly, the present invention provides an apparatus for displaying an image on a screen by horizontally and vertically scanning the screen with a modulated beam of light, the apparatus comprising at least one source of a beam of light; first deflecting means for deflecting said beam of light and operable to scan said deflected beam of light in a first substantially rectilinear path: and second deflecting means for further deflecting said deflected beam of light and operable to scan said further deflected beam of light in a second substantially rectilinear path at right angles to said first path.

The light source is preferably a laser and the light deflecting means are each formed by a number of plane mirrors arranged as the sides of a preferably regular polygon. The intensity of the light generated by the laser is modulated to provide the varying degrees of light and dark necessary to the build-up of the image.

For the display of colour images sources of different coloured light may be used to provide a composite colour picture via the reflecting means.

Typically red, green and blue laser light beams may be combined into a single beam of light using a suitable arrangement of mirrors before being transmitted to the two reflecting means.

The present invention is further described hereinafter, by way of example, with reference to the accompanying drawing which diagrammatically illustrates one form of apparatus according to the present invention.

The drawing shows one form of apparatus according to the present invention for displaying an image 2 on a screen (not shown in the drawings) by scanning the screen with a light beam 1, 3, 4 to build up the image from a number of laterally spaced parallel lines, in the manner in which a typical television image is formed.

The light beam is generated by a suitable light source 5 which may be a laser and is reflected by two reflecting means 7 and 10 to the screen.

Each reflecting means 7 and 10 is formed by a number of planar reflecting surfaces such as plane mirrors arranged to form the sides of a regular polygon which is rotated about its central axis.

The first reflecting means 7 reflects the original light beam 6 from the laser 5 to form a first reflected light beam 9 which is scanned in a substantially rectilinear path by rotation of the reflecting means 7, the scanning being from left to right or right to left depending upon the direction of rotation of the reflecting means 7.

The reflected beam of light 9 is intercepted by the second reflecting means 10 which is arranged with its rotational axis perpendicular to that of the first reflecting means 7, the result of which is that the beam 9 reflected by the first reflecting means 7 is further reflected onto the screen while being scanned by rotation of the second reflecting means 10 in a substantially straight path which is at right angles to the path through which the light beam 9 is scanned.

The intensity of the light beam 6 produced by the laser 5 is modulated such that the scanning of the screen by the light beam reflected by the two reflecting means produces an image which is built up in a manner similar to that of a television tube image. The modulation signals for the laser 5 can be derived from television video image signals.

A colour image can be produced using three light sources such as lasers to provide beams of red, green and blue collimated light. These can be combined into a single light beam using a suitable arrangement of reflectors such that separate modulation of the three light beams results in the production of a colour image on the screen.

Finally, although in the preferred embodiment reflection is used to deflect the light beam it will be appreciated that refraction or combination of both reflection and refraction might equally be used.

Claims

1. Apparatus for displaying an image on a screen by horizontally and vertically scanning the screen with a modulated beam of light, the apparatus comprising at least one source of a beam of light; first deflecting means for deflecting said beam of light and operable to scan said deflected beam of light in a first substantially rectilinear path; and second deflecting means for further deflecting said deflected beam of light and operable to scan said further deflected beam of light in a second substantially rectilinear path at right angles to said first path.

2. Apparatus as claimed in claim 1 wherein at least one of said deflecting means comprises a planar reflecting surface and said apparatus further comprises means for moving said planar reflecting surface to scan the reflected beam of light in said first or second rectilinear path.

3. Apparatus as claimed in claim 2 wherein said deflecting means comprises a plurality of said planar reflecting surfaces forming the sides of a regular polygon.

4. Apparatus as claimed in claim 3 wherein said moving means comprises means for rotating said polygon about its axis at a preselectable speed.

5. Apparatus as claimed in any of claims 1 to 4 wherein at least one of said deflecting means comprises a refracting medium and said apparatus comprises means for moving said refracting medium to scan the reflected beam of light in said first or second rectilinear path.

6. Apparatus as claimed in claim 5 wherein said means for moving said refracting medium

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Improvements relating to image display apparatus The present invention relates to apparatus for displaying an image. One of the problems associated with apparatus for displaying large scale images such as television images lies in the complexity of such apparatus and, where television tubes are concerned, the limitations placed on the sizes of the tubes. Accordingly, the present invention provides an apparatus for displaying an image on a screen by horizontally and vertically scanning the screen with a modulated beam of light, the apparatus comprising at least one source of a beam of light; first deflecting means for deflecting said beam of light and operable to scan said deflected beam of light in a first substantially rectilinear path: and second deflecting means for further deflecting said deflected beam of light and operable to scan said further deflected beam of light in a second substantially rectilinear path at right angles to said first path. The light source is preferably a laser and the light deflecting means are each formed by a number of plane mirrors arranged as the sides of a preferably regular polygon. The intensity of the light generated by the laser is modulated to provide the varying degrees of light and dark necessary to the build-up of the image. For the display of colour images sources of different coloured light may be used to provide a composite colour picture via the reflecting means. Typically red, green and blue laser light beams may be combined into a single beam of light using a suitable arrangement of mirrors before being transmitted to the two reflecting means. The present invention is further described hereinafter, by way of example, with reference to the accompanying drawing which diagrammatically illustrates one form of apparatus according to the present invention. The drawing shows one form of apparatus according to the present invention for displaying an image 2 on a screen (not shown in the drawings) by scanning the screen with a light beam 1, 3, 4 to build up the image from a number of laterally spaced parallel lines, in the manner in which a typical television image is formed. The light beam is generated by a suitable light source 5 which may be a laser and is reflected by two reflecting means 7 and 10 to the screen. Each reflecting means 7 and 10 is formed by a number of planar reflecting surfaces such as plane mirrors arranged to form the sides of a regular polygon which is rotated about its central axis. The first reflecting means 7 reflects the original light beam 6 from the laser 5 to form a first reflected light beam 9 which is scanned in a substantially rectilinear path by rotation of the reflecting means 7, the scanning being from left to right or right to left depending upon the direction of rotation of the reflecting means 7. The reflected beam of light 9 is intercepted by the second reflecting means 10 which is arranged with its rotational axis perpendicular to that of the first reflecting means 7, the result of which is that the beam 9 reflected by the first reflecting means 7 is further reflected onto the screen while being scanned by rotation of the second reflecting means 10 in a substantially straight path which is at right angles to the path through which the light beam 9 is scanned. The intensity of the light beam 6 produced by the laser 5 is modulated such that the scanning of the screen by the light beam reflected by the two reflecting means produces an image which is built up in a manner similar to that of a television tube image. The modulation signals for the laser 5 can be derived from television video image signals. A colour image can be produced using three light sources such as lasers to provide beams of red, green and blue collimated light. These can be combined into a single light beam using a suitable arrangement of reflectors such that separate modulation of the three light beams results in the production of a colour image on the screen. Finally, although in the preferred embodiment reflection is used to deflect the light beam it will be appreciated that refraction or combination of both reflection and refraction might equally be used. Claims

6. Apparatus as claimed in claim 5 wherein said means for moving said refracting medium comprises means for rotating said medium at a preselectable speed.

7. Apparatus as claimed in any of claims 1 to 6 wherein said light source comprises at least one laser light source.

8. Apparatus as claimed in claim 7 comprising three laser light sources operable to generate respective beams of red, green and blue collimated light and means for combining said beams into a single beam of light for enabling display of a colour image on said screen,

9. Apparatus for displaying an image on a screen by horizontally and vertically scanning the screen with a modulated beam of light, substantially as hereinbefore described with reference to the accompanying drawing.