GB2214692A - Display unit - Google Patents

Abstract

A display device is made up of a housing 10 which spaces a two way mirror 12 from a reflector 14 to define a plenum chamber 15 between the mirror, the housing and the reflector. The mirror and reflector provide the only reflecting surfaces directed into the plenum. At least one object or primary image is located in or projected into the plenum such that when it has sufficient illumination or intensity an observer looking into the plenum through the mirror from the side remote from the plenum sees a plurality of images of the object or primary image due exclusively to multiple reflections between the mirror and the reflector. Typically the device includes a drive for causing continuous or intermittent motion (which motion could include or comprise rotation) of the reflector relative to the mirror. One application is for an analogue display clock 18. <IMAGE>

Description

DISPLAY IT lis invention relates to a display unit. In particular it is concerned with a display unit making use of mirrors to produce an image or an array of images.

Display units are known which make use of two way mirrors.

In my GB Patent 2 053 546 F there is provided a display unit in the form of a decorative structure which includes a sheet of two-way mirror spaced from one or more light-reflective surfaces, a number of light reflective side walls totally surrounding the mirror and light-reflective surface or surfaces and extending between the mirror and the light -reflective surface or surfaces to form a box-like structure, said side walls being inclined outwardly in a direction towards the two-way mirror, and an object or image thereof so positioned that when it has sufficient illumination or intensity an observer looking at and through said two-way mirror from the side remote from the light reflective surface or surfaces sees a plurality of images of said object or primary image due to multiple reflections between the two-way mirror, the light-reflective surface or surfaces and the side walls.

In my GB Patent 2 055 499 there is described a display device which includes means for displaying an inage within a periphery in the form of a polygon, light reflecting panels extending to and surrounding the image periphery and being inclined outwardly towards an observer when looking in the direction of a central viewing axis at right angles to the image periphery in front of the panels, the arrangement of the panels being such that when the image is of sufficient brightness there is created to the observer an illusion of a three dimensional solid located within the device, said solid having a face presented directly towards the observer defined by the image periphery, said face being surrounded by other apparent faces created by reflections of the image periphery in the inclined panels.

Inhere has arisen a need for a display device which provides a plurality of images without a complexity of reflective surfaces as used heretofor.

According to the present invention there is provided a display device comprising: a housing serving to locate a two way mirror and a reflector spaced front the mirror. to define a plenum between the mirror, the housing and the reflector; and at least one object or primary image located in or projected into the plenum such that when there is sufficient object illumination or image intensity an observer looking into the plenum through the mirror from the side remote from the plenum sees a plurality of images of said object or primary image due exclusively to multiple reflections between the mirror and the reflector.

According to a first preferred form of the present invention the display device includes drive means either for causing continuous or intermittent displacement of the reflector relative to the mirror so as to vary the spacing of the reflector from the mirror of the plenum or for continuous or intermittent rotation of the reflector relative to the mirror or for a combination of continuous or intermittent displacement and continuous or intermittent rotation.

According to a second preferred form of the present invention or the first preferred form thereof the reflector incorporates at least one transparent aperture and there is provided at least one source of light or other radiation disposed on the opposite side qf the reflector to the mirror whereby an object disposed within the plenum chamber can be illuminated or an image can be maintained in the plenum chamber or on the walls thereof by projecting light or other radiation from the source by way of the transparent aperture into the plenum chamber.

According to a third preferred form of the present invention or the first or second preferred forms thereof the reflector serves to define or support a display (such as an analogue clock face) and there is provided at least one indicator to co-orserate with the display for the purposes of identifying a value or for some other function. Typically the reflector incorporates an array of transparent apertures disposed in a pattern about the reflector and the indicator comprises a needle with a driver adapted to cause the needle to indicate a particular part of the pattern in response to a predetermined input to the driver.

It will be apparent that the present invention is concerned with the use of only two reflecting surfaces (either or both which can be a two-way mirror) without the addition of inclined reflecting surfaces previously proposed.

An exemplary embodiment of the invention will now be described with reference to the accompanying drawings of a clock of which: Figure 1 is a front elevation, and Figure 2 is a section on section II-II of Figure 1.

The drawings variously show a tubular housing 10 which has concentrically mounted within it a sleeve 11. The housing and sleeve serve to locate and support a two way mirror 12 which is made of glass on which is deposited a coating of a to way mirror material (typically a layer of titanium or aluminium metal with a thickness measured in angstroms).

Sleeve 13 serves to slidably support within sleeve 11 a reflector 14 which is spaced from the mirror 12 to provide a plenum chamber 15. The reflector 14 is made up of a transparent carrier which has deposited on side nearest the mirror 12 an opaque layer 16 which reflects light falling on it from the general direction of the mirror 12. Certain areas of the layer 16 are removed (Figure 1) to provide on locus L a pattern of twelve transparent apertures, typically aperture 17, provide a clock face display. Typically one or more of the apertures incorporate an advertising logo in the form of a transparency or silhouette to be illuminated as will be described hereafter.

The side of the reflector remote from the mirror 12 carries a clock drive 18 which drives conventional hour, minute and second clock hands (respectively hands 19, 20, 21) on the side nearest the mirror 12 in a kno';n manner by way of a concentric shaft assembly 22.

Figure 2 shows backplate 23 which is located by the opposite end of housing 10 and sleeve 11 to that supporting mirror 12. The backplate 23 carries a curved discharge lamp 24 whereby the apertures on locus L making up the clock face display are illuminated if required.

The extent to which the two-way mirror 12 junctions as a mirror or as a transparent member depends on the relative degree of illumination on either side of the mirror. With an observer on the opposite side of the mirror 12 to the plenum chamber 15 light front the chamber can either pass to the observer or be subject to reflection back towards the reflector 14. With the illumination on the observers side of the mirror substantially less than that on the plenum side the mirror is effectively transparent and allows the passage of light out to the observer from the plenum chamber.

With the relative level of illumination reversed, that is to say with the greater illumination on the observers side, the mirror 12 tends to reflect a proportion of the light entering the chamber by way of the pattern of aperture including aperture 17, back towards the reflector 14 where it is in turn reflected back towards the mirror 12. This sequence of multiple internal reflections causes a multiplicity of images of the clock face as embodied by the apertures to be seen by the observer. In the event the illumination provided by the lamp 24 is removed the apertures will be unlit and little or no light will enter the plenum chamber from any direction except through mirror 12. In this case the clock display is without the multiple reflection effect.

Movement is provided to vary the appearance of the clock to an observer.

The housing 10 includes an extension 25 which encloses an electric motor 26 adapted to drive shaft 27. The shaft 27 extends through chamber 28 lying on the opposite of the reflector 14 to plenum chamber 15. The shaft 27 has circular cams 29, 30 mounted eccentrically upon it. The cams 29, 30 contact drive pads, respectively pads 31, 32, mounted on the rear face of reflector 14. With the motor 26 energized the shaft 27 and cams 29, 30 rotate causing the reflector 14, and so sleeve 13, to be displaced linearly backwards and forwards with consequent variation in the volume of the plenum chamber 15. The sleeve 13 is suitable slotted to allow the sleeve to move relative to the shaft. The drive pads extend to engage the side of the cams diametrically opposite that shown so that the cams 29, 30 can serve to both push and pull the reflector 14.

With the lamp 24 illuminated to provide the multiple reflective effect described previously the addition of movement causes the multiple reflections to vary in a striking and attractive way especially to an observer slightly off-set from the centre line of the housing 10.

In addition to or as a replacement for a light source a source of some other form of radiation can be used to provide radiation which will produce luminescence or some other visual effect in a suitably prepared object disposed within the plenum.

Claims (6)

1A display device comprising: a housing serving to locate a two way mirror and a reflector spaced from the mirror to define a plenum between the mirror, the housing and the reflector; and at least one object or primary image located in or projected into the plenum such that when there is sufficient object illumination or image intensity an observer looking into the plenum through the mirror from the side remote from the plenum sees a plurality of images of said object or primary image due exclusively to multiple reflections between the mirror and the reflector.

2 A display device as claimed in Claim 1 including drive means either for causing continuous or intermittent displacement of the reflector relative to the mirror so as to vary the spacing of the reflector from the mirror of the plenum or for continuous or intermittent rotation of the reflector relative to the mirror or for a combination of continuous or intermittent displacement and continuous or intermittent rotation.

3 A display device as claimed in Claim 1 or Claim 2 wherein the reflector incorporates at least one transparent aperture and there is provided at least one source of light or other radiation disposed on the opposite side of the reflector to the mirror whereby an object disposed within the plenum chamber can be illuminated or an image can be maintained in the plenum chamber or on the walls thereof by projecting light or other radiation from the source by way of the transparent aperture into the plenum chamber.

4 A display device as claimed in any preceding claim wherein the reflector serves to define or support a display (such as an analogue clock face) and there is provided at least one indicator to co-operate with the display for the purposes of identifying a value or for some other function.

5 A display device as claimed in Claim 4 wherein the reflector incorporates an array of transparent apertures disposed in a pattern about the reflector and the indicator comprises a needle with a driver adapted to cause the needle to indicate a particular part of the pattern in response to a predetermined input to the driver.

6 A display device as hereinbefore described with reference to the accompanying drawings.