SG195397A1

SG195397A1 - Projection screen

Info

Publication number: SG195397A1
Application number: SG2012033767A
Authority: SG
Inventors: Jain Siddharth
Original assignee: Playware Studios Asia Pte Ltd
Priority date: 2012-05-08
Filing date: 2012-05-08
Publication date: 2013-12-30
Also published as: SG11201408631SA; WO2013169206A1

Abstract

PROJECTION SCREEN5 A system and a method creating a screen such that can alternate between anopaque projection surface, a partially transparent projection surface and a transparent glass meant to be installed in places where the projector and the intended viewer are on one side of the screen and the opposite side has a bright light source (sunlight etc.) 10 (Fig. 3)

Description

PROJECTION SCREEN

TECHNICAL FIELD

The present invention relates to a projection screen.

DESCRIPTION OF THE RELATED ART

Currently there are two main types of screen that can display a projected surface these are classified into Front and Rear projection screens.

Front projection screen type is shown in Fig. 1

In front projection systems the viewer 10 is on the same side of the screen 12 as the projector 14. This system of projection has several limitations: e The screen is usually opaque to allow maximum light to be reflected off it and back to the viewer. e This opacity also prevents other light sources 16 behind the screen from diluting the visibility of the projected image. e Even when no projection is being cast on the screen the viewer cannot see what is behind the screen without physically moving it (including rolling, collapsing, folding etc.)

Rear screen type is shown in Fig. 2.

In rear projection systems the viewer 10 is on the opposite side of the screen 12 in relation to the projector 14. This kind of projection system also has several limitations: e The screen is usually clear or translucent or made of a light diffusing surface. This creates one of the following three experiences: o The viewer can see the image projected if the screen is of the clear type but the image is diluted if there is a strong light source on either side of the screen. While no image is being projected the viewer can see through the screen to the other side. o The viewer can see the image in most lighting conditions but is not able to see though the screen with any clarity If the screen is of the translucent type. o The viewer can see the image projected on the screen from either side of the screen in most lighting conditions on either side but cannot see through the screen.

Conclusions drawn from Figures 1 and 2

If there is a need to have the viewer and the projector on the same side of the screen both the above commonly and currently used types of projection systems of the variations described here and above will suffer from one or more of the following limitations: e The surface will not allow the viewer to see clearly across the screen. e The screen will not be able to display clearly visible images in any condition where there are any other strong light sources but the projector on either side of the screen. e The screen will display a brighter image on the side opposite to the projector and the viewer rather than towards the viewer. e The projected image will be visible on the opposite side of the screen.

Clearly a new method is needed if it is desirable to overcome the above limitations.

SUMMARY OF THE INVENTION

A system and a method creating a screen such that can alternate between an opaque projection surface, a partially transparent projection surface and a transparent glass meant to be installed in places where the projector and the intended viewer are on one side of the screen and the opposite side has a bright light source (sunlight etc.)

I

Embodiments of the invention relate to providing a method and apparatus for creating a screen such that can alternate between an opaque projection surface, a partially transparent projection surface and a transparent glass. Further the screen has the following properties: e It can display an image which is front projected (projector and viewer are on the same side) even if there is a strong light source behind the screen. e The projected image in both the opaque and the partially transparent modes are only visible from the projector’s side of the screen. e The projected image (in both the opaque and the partially transparent modes) is visible regardless of the lighting conditions on the non-viewer side of the screen

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 shows one type of conventional projection screen.

Fig. 2 shows another type of conventional projection screen.

Fig. 3 shows an overall structure of a projection screen according to one embodiment of the present invention.

Fig. 4 shows a detailed structure of a private layer used in the projection screen of

Fig. 3.

Fig. 5 shows an overall structure of a projection screen according to one embodiment of the present invention together with a projector and a viewer.

DETAILED DESCRIPTION

As shown in Figs. 3 to 5, according to one embodiment, the screen is constructed from several layers of Film and glass to create the desired effect. The various layers can be placed one after another and may be glued together using standard or UV clear glue or other adhesive. Other forms of fastening of the layers with each other such as by the use of a vice or nuts and bolts can also be used to achieve the desired stacking effect. There is a limited ability to alternate the priority of the layers up or down the order to achieve the same effect.

The base or rigidity layer of the screen can be made of Clear Tempered Glass, Acrylic or polycarbonate or any other solid material that allows Greater 90% visibility through it and provides rigidity to the screen.

The Privacy layer is composed of a film or glass or acrylic that is which allow one way vision One way vision glass can be obtained by installing a high reflective window film.

Reflective window tint is generally made from two sheets of polyester, which has been through a process that deposits a layer of very small particles of metal, usually, aluminum, silver or bronze. This creates a very thin metalized layer in between the polyester sheets, a clear adhesive and thin polyester backing liner is attached and on the other side a scratch resistant coating.

When this reflective window film is applied to glass it creates a one way mirror under the correct conditions. The most common reflective window film is a reflective silver window film, the darkest usually referred to as silver 20. This silver film gives a silver mirrored appearance; other colors can be combined such as grey, gold and bronze. For the purposes of this invention the reflectiveness should be limited between 30-70%. Additionally this film may provide up to 99% reduction of UV light transmission.

The Opacity layers/layers are successively made of Polymer-dispersed liquid crystals (PDLC) layer. PDLCs consist of liquid crystal droplets that are dispersed in a solid polymer matrix. The resulting material is a sort of "Swiss cheese" polymer with liquid crystal droplets filling in the holes. These tiny droplets (a few microns across for practical applications) are responsible for the unique behavior of the material. By changing the orientation of the liquid crystal molecules with an electric field e, it is possible to vary the intensity of transmitted light.

In a typical application, a thin PDLC film (about 25 microns thick) is deposited between clear plastic covers. The plastic substrates are coated with a very thin layer of a conducting material known as indium tin oxide (ITO).

In the charged state this layer allows Light through for clear visibility through the screen and in the dormant state the particles disperse and diffuse the light creating a surface with more than 90% opacity.

There may be two or more such layers connected to the power source such that can be charged together of individually to create varied levels of opacity.

These layers can also be segmented into a grid such that the various cells in the grid can be controlled independently from each other.

Aside from using PDLC similar effect can also be achieved by using suspended particle display (SPD) or Liquid crystal display (LCD) glass or films.

The Priority of the rigidity layer may be changed but the opacity layer must always be between the viewer and the privacy layer.

Embodiments of the invention provide the following advantages: e It can display an image which is front projected (projector and viewer are on the same side) even if there is a strong light source behind the screen. e The projected image in both the opaque and the partially transparent modes are only visible from the projector’s side of the screen. e The projected image (in both the opaque and the partially transparent modes) is not visible regardless of the lighting conditions on the non-viewer side of the screen

Other modifications and embodiments will be apparent to those skilled in the art from consideration of the specification and practice of the invention. Furthermore, certain terminology has been used for the purposes of descriptive clarity, and not to limit the disclosed embodiments of the invention.

Claims

1. A Projection Screen comprising a base layer; an opacity layer, and. a privacy layer sandwiched between the base layer and the opacity layer.