WO1998039917A1

WO1998039917A1 - Liquid crystal display screen adapted for a slide projector

Info

Publication number: WO1998039917A1
Application number: PCT/AU1998/000138
Authority: WO
Inventors: Kevin James Soper; Philip Brendan Banks
Original assignee: Digislide International Pty Ltd
Current assignee: Digislide International Pty Ltd
Priority date: 1997-03-05
Filing date: 1998-03-05
Publication date: 1998-09-11
Anticipated expiration: 1999-09-05
Also published as: AUPO544897A0

Abstract

This invention is for a method and apparatus to display images on a screen or surface by the use of a conventional slide projector. Slide projectors display images that are contained within slides. Accordingly a liquid crystal display screen adapted to be used as a normal slide is inserted into a slide projector and used to display pictures or moving images. The slide projector then simply projects the images within the liquid crystal display screen and displays them on a suitable surface area. The size and location of the projected image can be controlled by the distance from the slide projector to the surface area, with the image being focusable by suitable optics. The distance as well as the number of pixel's found within the liquid crystal display screen determine the resolution of the image. Thus this provides for an inexpensive and simple method and apparatus for the display of large images which has hitherto been possible only with large and expensive television receivers.

Description

LIQUID CRYSTAL DISPLAY SCREEN ADAPTED FOR A SLIDE PROJECTOR

This invention is directed to a method and an apparatus to display large video or television images and specifically to a method and apparatus that adapts conventional slide projectors that are currently used to display slides.

BACKGROUND OF THE INVENTION

Since the advent of television, home entertainment has become an integral and focused part of everyday life. For that reason, numerous improvements to both television, video and audio systems have been common place during the last several decades.

One of the most common sought after improvements is the ability to produce an image of bigger and bigger size, hopefully whilst still maintaining good resolution. Until the advent of large screen televisions this has only been possible in commercial areas such as theatres where reel-to-reel films are used to project an image onto a screen. For the domestic or professional market however, whether it be television or video, the only known way to produce a large image is by simply using a bigger television screen. The difficulty with large television screens is that they are inherently expensive, are relatively complex and thus expensive to repair, and by their large size are not very mobile or portable.

It is an object of this invention to provide a method and/or and apparatus to display a image, or to at least provide the public with a useful alternative.

SUMMARY OF THE INVENTION

Therefore, in one form of the invention although this need not be the only or indeed the broadest form there is proposed an apparatus for use with a slide projector comprising a liquid crystal display screen, said liquid crystal display screen being of a shape and size to locate in an operative position in a slide projector to enable illumination through said liquid crystal display screen for projection onto another surface.

In preference the liquid crystal display screen is adapted to be inserted into the slide projector as a conventional slide.

In preference the apparatus further comprises a transparent heat shield means attached to at least one side of the liquid crystal display.

In preference the liquid crystal display screen further includes a heat shield.

In preference the liquid crystal display screen is divided into a plurality of individual screens to thereby allow one image to display separate images.

In preference the signals input into said liquid crystal display screen are provided by a transmitter adapted to transmit the signals, and a receiver adapted to receive the signals and output the signals them to said liquid crystal display screen.

In preference the slide projector comprises an adjustable lens to thereby focus the image onto said surface area.

In preference the provides an image to an liquid crystal display screen, and whereby the liquid crystal display screen is adapted to be used with a slide projector which projects light through said liquid crystal display screen and onto a surface area.

In a further form of the invention there is proposed an adaptor comprising a controlled transparency liquid crystal display panel, and a supporting perimeter frame which frame has a shape, width and perimeter dimensions such that the frame will locate in an operative position in a transparent slide illuminating projector and hold the panel for illuminating projection therethrough from such a projector.

In a yet further form of the invention there is proposed in combination an adaptor comprising a controlled transparency liquid crystal display panel, and a supporting perimeter frame which frame has a shape, width and perimeter dimensions such that the frame will locate in an operative position in a transparent slide illuminating projector and an illuminating projector having the panel so located therein. BRIEF DESCRIPTION OF THE DRAWINGS

FIG 1 is a perspective view of a first embodiment of the invention when used with a slide projector incorporating a liquid crystal display (liquid crystal display) screen adapted to be used with a slide projector;

FIG 2 is a perspective view of a second preferred embodiment of the apparatus;

FIG 3 is a perspective view of the apparatus of Figure 1 used to display an image;

FIG 4 is a perspective view of a third embodiment of the invention when used with a slide projector;

FIG 5 is a perspective view of a fourth embodiment of the invention;

FIG 6 is a perspective underside view of the fourth embodiment of the invention;

FIG 7 is a perspective view of a slide projector incorporating a fifth embodiment of the invention;

FIG 8 is a partial cross-sectional view of a slide projector when projecting light through a liquid crystal display screen;

FIG 9 (a) and (b) are partial cross-sectional views of an improved slide projector incorporating a heat shield for the liquid crystal display screen showing the liquid crystal display being outside of and inside of the slide projector respectively; and

FIG 10 (a) and (b) are partial cross-sectional views of a liquid crystal display screen incorporating a heat shield outside of and inside the slide projector respectively.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Turning now to the drawings in detail it is to be understood that like numerals are used to indicate like elements. Thus there is shown in Figure 1 a slide projector 10 that is commonly used to show slides (not shown) by inserting a slide into aperture 12 whereupon an internal light (not shown in Figure 1) projects a light through a slide contained within aperture 12 and through lens 14 to be displayed on some surface such as a screen a wall or even a sheet hanging of furniture. The lens 14 is further generally adjustable in focus so as to project a clear image onto the screen depending on the distance from the slide projector to the screen.

Slide projectors are usually constructed either to take individual slides, or are adapted to accommodate a slide holder that may take a number of slides. Slide holders may further be of a linear construction or a carousel. In both cases the slide holder is adapted to change slides automatically without the necessity to manually change the slides.

This invention makes use of the fact that a slide projector is adapted to project light through a slide. By using a small display screen, such as a liquid crystal display screen commonly found in hand-held television receivers although either screen may very well be used, whose size is constructed to be similar to that of a slide and which is adapted to be inserted into the slide projector aperture 12, one can then project whatever image is being displayed by the display screen in much the same way as one uses the slide projector to display slides. Since the screen slide 18 can be used to display either television or video or any other image, with the slide projector simply projecting and thereby greatly enlarging whatever image is being shown by the screen, one obtains an image whose size may be greater than that available by conventional television receivers and whose resolution is dependant only on the total number of pixel's contained within the slide screen and the ultimate size of the image is fully controllable by the user.

Thus one can envisage that some may wish to have an image whose size is comparable to a normal television screen whilst other may wish to have an image size which is only limited by the total area of the surface on which the image is to be displayed. Furthermore, the use of a slide projector gives complete control on exactly where the image will be shown, that is both in its vertical and horizontal orientation and thus provides a great deal of flexibility and comfort to the user which hitherto is quite difficult with conventional television receivers simply due to their size. Accordingly as shown in Figure 1 , the apparatus 16 that controls the liquid crystal display screen slide 18, hereinafter termed the digislide, is simply placed on top of a standard slide projector, and aligned so that the liquid crystal display screen slide 18 which protrudes from the bottom of the digislide 16 is inserted into the aperture 12 of the slide projector 10. Obviously the depth that the liquid crystal display screen slide projects into the slide projector must be accurate so that the liquid crystal display screen is in the correct position. The digislide 16 unit also may include a fan 20 which is designed to provide an airflow around the liquid crystal display screen slide and thus cooling which would normally exposed to the intense heat from the lamp of the slide projector.

The liquid crystal display screen slide may be used to display either moving pictures that may be provided from normal television signals or from a video, that image then simply enlarged and projected from the slide projector. Obviously the liquid crystal display screen may equally well be used to show stationary pictures and in this way the digislide may be used to act as simply a series of slides, thereby removing the need to load different slides. A further adaptation may be that the image projected onto the liquid crystal display screen slide may be those from a computer as is commonly used in various lectures and seminars providing both moving and stationary images.

In a second embodiment of the invention, where it may be difficult or impractical for the digislide unit to be placed on top of the slide projector, the digislide may input an image into the liquid crystal display screen slide via a cable 24 as is shown in Figure 2. This enables the digislide apparatus 16 to be placed alongside the slide projector or even underneath, with the liquid crystal display screen slide being manually inserted into the aperture 12 of the slide projector. The digislide apparatus may also include an antenna connection 25 that may be used to feed a signal into the digislide. Alternatively the digislide may itself contain a video player to provide an image to the liquid crystal display screen slide.

Figure 3 therefore shows the digislide 16 in use whereupon the digislide is placed on top of the slide projector 10 and by providing an image to the liquid crystal display screen slide 18 contained within the slide projector, one may project an image 26 onto a screen 28. In a further embodiment of the invention, the liquid crystal display screen slide may be adapted to receive remote signals. This is illustrated in Figure 4 wherein the liquid crystal display screen slide 18 obtains signals from a remote receiver 30 through cable 31. The remote receiver 30 receives transmitted signals 32 from transmitting unit 34, which may be a video tape recorder/player or a television receiver. This embodiment removes the necessity for cabling and allows for the carousel 36 to rotate without any of the cabling being tangled up. Thus one could display a combination of slides and a moving image since the liquid crystal display screen slide 18 could be positioned in a particular slide holder within the carousel 36. One could also envisage include a plurality of liquid crystal display screens fed from the receiver if one wanted to show images in between slides. Of course in the scenario where the liquid crystal display screen slide 18 was used to show both moving images and stationary pictures the need for the carousel would be obviated. However, if the pictures are not able to be displayed through the liquid crystal display screen slide then one would need to use the carousel.

A further embodiment of the digislide is shown in Figure 5 wherein the liquid crystal display screen slide is able to be retracted into the digislide. Thus, the digislide could be adapted to fit over the top of the slide projector with the liquid crystal display screen to be inserted into the aperture 12 when required. This could be accomplished by the use of retractable arms 40 that simply retract and lower the liquid crystal display screen slide 18. This embodiment is further illustrated in Figure 6 wherein the liquid crystal display screen slide 18 shown in its retracted position within the digislide by the dashed lines. This embodiment enables the liquid crystal display screen slide to be safely stored when it is not in use and thereby minimise damage to the liquid crystal display screen slide and further make it easier for transportation and packaging.

A yet further embodiment of the invention is illustrated in Figure 7 wherein there is a liquid crystal display screen slide 18 permanently installed within the slide projector 10 and adapted to be inserted into the correct position to be illuminated by the lamp within the slide projector. Thus one could have the situation where a carousel 36 is used to display a number of slides and the liquid crystal display screen slide 18 is simply inserted into the correct position when required. Although not shown in Figure 7 the liquid crystal display screen slide is controlled by appropriate cabling or remote transmission. A further embodiment, although not illustrated may include a single slide projector which incorporates a video player or television receiver.

Thus one can see that the present invention provides for the ability to produce an image of a desirable size by the adaptation of a common slide projector. As shown in Figure 8, the liquid crystal display screen slide 18 is simply placed in the appropriate position as would be a normal slide in a slide projector 10, with a lamp 42 providing light to illuminate and shine through the liquid crystal display screen slide 18, lens 14 and onto a surface area such as a screen.

Thus one can see that the digislide slide may be used as a television receiver, to play video tapes and even projects an image from a computer system, such as which may occur when children and adults alike play computer games, the size of the image being dependent only on the lens and the distance to the screen.

A difficulty that may arise with using an liquid crystal display screen slide within the projector may be that the lamps from the slide projector are known to produce an intense amount of heat. Accordingly as shown in Figure 9, the liquid crystal display screen slide may further include a heat shield that protects the screen slide form that heat. The heat shield may be constructed wither within the slide projector as shown in Figure 9 where the embodiment shows the heat shield 44 stationary within slide projector, and the liquid crystal display screen slide being outside of and inserted within the slide projector 10 in Figures 9 (a) and (b) respectively.

Alternatively, the liquid crystal display screen slide itself may contain a heat shield 44 as shown in Figure 10. This requires that the thickness of the liquid crystal display screen slide incorporating the heat shield be no larger than the aperture 12 of the slide projector to enable the liquid crystal display screen slide to be inserted into the aperture.

It is to be understood that the above apparatus provides for the display of pictures that are enlarged by the use of slide projector. With respect to audio that may be provided either by the digislide or by a separate apparatus which has the capability to reproduce sound accompanying the moving picture. This has however not been illustrated in the accompanying drawings. It is to be also understood that although the above illustration referred to the use of a liquid crystal display screen slide, other types of screens may be used. It is to be also understood that the resolution of the final displayed image will depend on a number of factors such as the number of pixel's within the liquid crystal display screen slide and the final size of the displayed image. Depending on the application, low resolution liquid crystal display screen slides may well be suitable with high resolution screen slides only necessary for high quality images. The only requirements is that the liquid crystal display screen slide be adapted to be used with a normal slide projector, and thus the size of the liquid crystal display screen slide is limited to that of conventional slides

Many other improvements may be made to the apparatus and still falling within the scop of the invention. Various optics and filters may be used to improve or changes the quality or colour of the image. It may also be possible to provide a liquid crystal display screen slide that may incorporate two individual screens, and allows one to display two simultaneous images. This though may be controlled by the signals that are fed into the liquid crystal display screen slide and may not require any change in the construction of the liquid crystal display screen slide.

Claims

1. An apparatus for use with a slide projector comprising a liquid crystal display screen, said liquid crystal display screen being of a shape and size to locate in an operative position in a slide projector to enable illumination through said liquid crystal display screen for projection onto another surface.

2. An apparatus as in claim 1 wherein the liquid crystal display screen is adapted to be inserted into the slide projector as a conventional slide.

3. An apparatus as in any one of the above claims further characterised in that there is transparent heat shield means attached to at least one side of the liquid crystal display.

4. An apparatus as in any one of the above claims wherein the liquid crystal display screen further includes a heat shield.

5. An apparatus as in any one of the above claims wherein the liquid crystal display screen is divided into a plurality of individual screens to thereby allow one image to display separate images.

6. An apparatus as in any one of the above claims further wherein the signals input into said liquid crystal display screen are provided by a transmitter adapted to transmit the signals, and a receiver adapted to receive the signals and output the signals them to said liquid crystal display screen.

7. An apparatus as in any one of the above claims wherein the slide projector comprises an adjustable lens to thereby focus the image onto said surface area.

8. A method for the display of images comprising an apparatus to provide an image to an liquid crystal display screen, and whereby the liquid crystal display screen is adapted to be used with a slide projector which projects light through said liquid crystal display screen and onto a surface area.

9. An adaptor comprising a controlled transparency liquid crystal display panel, and a supporting perimeter frame which frame has a shape, width and perimeter dimensions such that the frame will locate in an operative position in a transparent slide illuminating projector and hold the panel for illuminating projection therethrough from such a projector.

10. In combination an adaptor comprising a controlled transparency liquid crystal display panel, and a supporting perimeter frame which frame has a shape, width and perimeter dimensions such that the frame will locate in an operative position in a transparent slide illuminating projector and an illuminating projector having the panel so located therein.