GB2308005A - Imaging display unit - Google Patents

Abstract

An imaging display unit contains multiple images printed onto a single two dimensional surface. A viewing screen which is physically separated from the image surface decodes the images to reveal animation or stereoscopic effects. The viewing screen is typically a lenticular lens array or barrier screen and uses an image panel which may be readily removed and replaced, in correct register, by its replacement. The images may be generated electronically or through projection.

Description

REUSABLE DIRECTION SELECTIVE OPTICAL SCREENS.

This invention relates to a reusable direction selective optical screen.

Lenticular lens arrays and barrier grids are well known direction selective optical viewing screens. These devices allow specific sections of an interlaced composite image to be seen, according to the viewing position of the viewer in relation to the selector screen and the image combined behind or in front of it. Normally, the image is permanently laminated, or printed directly directly onto the reverse face of the direction selective viewing screen.

Large displays are relatively very expensive when compared to conventional images due to the additional cost of the lenticular or barrier screen. They are also heavy and awkward to hamdle when being removed and replaced.

According to the present invention, there is provided a specially designed optical viewing screen which is mounted in the display unit such that the image alone may be replaced without the need for replacing the screen as well.

A specific embodiment of the invention will now be described by way of example with reference to the accompanying drawing in which: Figure 1 shows the viewing screen V , mounted at a distance D from the supported image I, viewed by an observer 0.

Figure 2 illustrates the removal and replacement of the image I without disturbing the permanently mounted viewing screen V.

Figure 3 illustrates the use of adjustment screws S to true up the viewing screen V and the Imaging panel I, relative to each other.

Referring to Figure 1, it will be seen that the image is actually spaced away from the viewing screen, and is separated by air or a physical optically clear spacer.

This is in comparison to conventional viewing screens which are designed to require the image to be in intimate contact with that screen, and to be physically and permanently bonded so as to form an unsplittable assembly.

The ability for the viewing screen to function at a substantial disLance from the image is achieved by designing the focal length of the screen to be greater than the thickness of the screen itself. For a given lens pitch, this is achieved by designing a longer focal length lens profile.

The correct focal length of the viewing screen is calculated so as to equal the total distance to the image including the air gap or optical spacer.

The actual distance is critical within some 5% for optimum perforance of the assembly and will vary according to the refractive index of the spacer medium, primarily whether the gap is air or an optically clear spacer.

To maintain the correct distance between the viewing screen and an image which may be on a flexible base, additional pices of clear plastic may be inserted into the air space to add rigidity.

In use, the viewing screen is semi permanently mounted into the display unit, whereas the image itself is rapidly replaced.

typically by slotting it into position from the side, or affixing it from the front or back by means of a hinged door.

Correct alignment and registration between the image and the selector screen is vital for correct function of the assembly, and this may be achieved by firstly ensuring correct registration in production using alignment systems, and then by subsequent truing up on installation.

Accurately parallel and square lower ledges allow for insertion of semi rigid images with good accuracy, with the minimum of adjustments on site, typically using alignment screws. An alternative method, which is particularly important for images which are strung up using suspension springs rather than being self supporting, includes adjustment screws which will allow for correcting vertical and horizontal registration.

It is vital that the lines on the selector screens are parallel to the matching lines in the image itself, and a bowed viewing and image screen can help the surfaces to intimately fit together in register.

Rather than have a printed image, the image may be generated from an electronic or projected means, whereby it is the relative motion of the observer which causes the animation to appear, rather than a moving image itself.

Claims (7)

1 A multi image display system, capable of displaying stereoscopic or animation effects, by means of multiple images printed onto a single flat surface printed image, which are viewed through a lenticular or barrier viewing screen which itself is not permanently attached to the image.

2 A multi image display system in which the viewing screen is separated from the image by means of air spacing or an additional layer of an optically clear material, or both.

3 A multi image display system in which the air gap between viewing screen and image is partially or totally filled with plastic spacers so as to support the image relative to the screen , yet without distorting the viewed image.

4 A multi image display system in which the panel containing the image may be readily replaced and re-aligned with the already installed viewing screen.

5 A multi image display system which contains adjustment controls in order to correctly register and align the image to the viewing screen.

6 A multi image display system in which the viewing screen may be slightly curved in order to create a positive fit-up between th viewing screen and the printed image.

7 A multi image display system in which the display is electronic but which, if static, appears to move purely by the motion action of the observer relative to the viewing screen.