WO1990012384A1

WO1990012384A1 - Device for displaying an image on a screen, especially outdoors

Info

Publication number: WO1990012384A1
Application number: PCT/FR1990/000226
Authority: WO
Inventors: Jean-François CHANTARAUD
Original assignee: Dasco
Priority date: 1989-03-30
Filing date: 1990-03-30
Publication date: 1990-10-18
Also published as: FR2645313A1

Abstract

The device comprises means for splitting the image (9), suited to the reception of a video signal (7), and the production of a plurality of sub-signals (SS), relative to discontinuous and complementary sub-assemblies of the image to be displayed; a plurality of liquid crystal units for colour display (15), which receive said sub-signals, and means (12, 13) for lighting up the liquid crystal windows of said units from behind, with essentially white light, in order to define the sub-images thereon. Means for anamorphosis (16) are arranged in order to transfer, with magnification, said sub-images to a large screen (E) which is divided into sections corresponding to the shape of the liquid crystal unit windows.

Description

Device for displaying an image on a screen, especially outdoors

The invention relates to the display of an image on a screen.

It is particularly interesting to generate an image on a screen, preferably capable of colors, which is visible in direct sunlight. Some applications require a large screen that can go up to an area of around 100 m ---.

A great deal of research has been carried out in this field and has not resulted to date in any known device which is on the one hand technically satisfactory and on the other hand industrially feasible at a reasonable price.

The invention aims to provide a solution to this problem.

The object of the invention is to propose a device capable of generating on a screen, preferably large dimensions, an image preferably capable of colors which is notably visible outdoors in direct sunlight.

Another object of the invention is to propose a modular arrangement.

Another object of the invention is to enable the obtaining of an image free from internal separation strips.

The object of the invention is also to display such an image from outside at very large angles.

The invention also relates to the creation of images, in particular animated, from various sources. Another object of the invention is to propose such a device at a very economical price, using in particular a large part of the conventional components of the trade.

The invention therefore relates to a device for displaying an image on a screen, of the type comprising:

processing means for drawing an optical image, for example from a video signal, and

- the ^'means based on optical fibers, for transfe rer said optical image on the screen, with particulie anamorphosis.

According to a general characteristic of the invention, the processing means comprise:

image cutting means, suitable for receiving the video signal, and for delivering a plurality of sub-signals, relating to disjoint and complementary subsets of the image,

a plurality of liquid crystal display units, receiving respectively said sub-signals, and

. means for illuminating the liquid crystal window of said units, from the rear, and in appreciably white light, in order to define sub-images therein;

provision is therefore made for the anamorphic means to be arranged to transfer said sub-images with magnification on the large screen cut into sections homologous to the shape of the windows of the liquid crystal units. Other advantages and characteristics of the invention will appear on examining the detailed description below and the attached drawings in which:

FIG. 1 is a schematic block diagram of an embodiment of a device according to the invention,

FIG. 2 schematically illustrates more particularly a part of the device of FIG. 1, and

Figure 3 is a schematic representation of a module of the device according to the invention.

The drawings essentially contain elements of a certain character. As such, they form an integral part of the description and can not only serve to better understand the detailed description below, but also contribute, if necessary, to the definition of the invention.

A video monitor 1 makes it possible to display, on its control screen, an image intended to be displayed on screen E. The displayed image can be obtained from composite video signals 3 coming from various sources such as a camera, a video recorder, a video disc Once the source has been manually selected by a selector 2, the signals are possibly processed by a converter 4 if their standard is not compatible with that of the monitor.

The monitor 1, possibly remotely controllable, can also receive antenna signals 6. It outputs a video signal representative of the image to be displayed on the screen E. This video signal 7, possibly converged in a frequency converter 50 Hertz / 60 Her 8, will be processed in order to draw an optical image therefrom intended to be transferred to the screen E.

To this end, the processing means comprise image cutting means 9 suitable for receiving the video signal 7 and for delivering (FIG. 2) a plurality of sub-signals SS, relating to disjoint and complementary subsets of the image, to a modular electro-optical assembly 11. Each of these sub-assemblies is managed selectively, within the means 9, by a cutting unit 90 and a general management unit 10, such as an icro computer , allows to control all of the cutting unit 90 so as to produce various effects on the image, in particular to animate it. It is also possible to generate alphanumeric characters on the background of the image.

These image cutting means are for example those used in the "image wall" generation devices sold for example by the company SYNELEC under the name SPACEVISION. The term “image wall” is understood here to mean a wall of several square meters formed by a plurality of televisions placed side by side.

Each of the SS sub-signals is delivered to a liquid crystal color display unit 1, for example of the type marketed by CITIZEN under the reference UC 400 and / or UC 401 for NTSC video, or else TC 63 for the PAL / SECAM video standard Such a unit conventionally comprises a liquid C-fiStaux window and an electronic interface.

Each of the windows of these display units 1 is lit from behind by a light which is appreciably white, for example from a bundle of optical fibers.

14 from a general light source 12 equipped a reflector 13.

By lighting this window from the rear, we just project the sub-image corresponding to the subset of the total image, on the input of anamorphic means 16, based on • optical fibers. These optical anamorphosers have the property of transmitting this subimage with a homothetic magnification at their exit face which then constitutes a screen section homologous to the form of the window of the corresponding display unit.

Thus, the electro-optical assembly 11, is composed of a plurality of optical blocks each comprising a screen sectio, the namorphosor with optical fibers corresponds 16 and the liquid crystal unit 15.

The principle of operation of the device is alo the following. The large image displayed on the screen E is obtained by cutting the input image viewed on the monitor, into a number of sub-images corresponding to the number of optical units. The sub-images displayed on their respective screen section, together form the large image.

The invention starts from the observation that the combination of image cutting means, the plurality of liquid crystal display units, lighting means and anamorphosers, makes it possible to provide a solution to the problem. posed.

This combination makes it possible in particular to obtain an ima of large dimensions, visible in particular in direct sunlight, and free of separations or of black bands between the screen sections such that one can for example observe them on the video walls. This observation is all the more surprising since this elimination of the internal separations of the image between the screen sections is obtained by using image cutting means of the same type as those used for video walls. In other words, while these means allow, in the application to video walls, a division of the image taking into account the physical separation between the various televisions, which causes these separations or black bands at 1 inside 1'image, these means enable herein in combination with other means according to ^Dr. invention, to obtain an image of better quality and greater visual comfort.

As illustrated in FIG. 3, an anamorphic unit 16 of an optical unit of the device comprises, on the side of its free face, or exit face, a frame 161 now holding a black shell, flush with the free face from which emerges The outlet ends of a bundle of optical fibers made of synthetic material 163 with a diameter of 0.5 mm. This bundle comprises 19,200 fibers linked to the plate by 160 connection strips 162 each comprising 120 fibers. These are arranged according to a two-dimensional step chosen depending on the application. It can vary for example from 2 mm to 5 mm, which will then lead to a rectangular outlet frame which may have a format, from 320 mm x 240 mm to 800 mm x 600 mm.

- On the side of the anamorphic inlet face, that is to say the face opposite its outlet face, these fibers are gathered in 160 strips each containing 120 contiguous fibers, mutually secured by a resin. "

In this application, the fiber bundle then defined, an entry face of dimensions 80 mm x 60 mm with a diagonal of approximately 10 mm (4 inches). Although the screen section is here constituted simply by the free outlet ends of the fibers 163 leading out flush with the black plate, it is also conceivable to have on this screen section, means forming a filter and / or optical diffuser.

The display unit 15 is secured to the anamor phoseur 16 so that the liquid crystal color window proper 150, of the same dimensions as the entry face thereof, is located exactly opposite the latter. Optical coupling means are also provided between the liquid crystal unit and the associated fibers. These means may simply be the free entry ends of the fibers arranged opposite the window. One could also conceive that these ends are treated, for example by polishing, to ensure such coupling.

The optical unit also includes the electronic interface 151 of this liquid crystal unit, intended for receiving the sub-signals coming from the cutting means.

Although a white light distribution from a single source has been described above by distribution means such as optical fibers, it is possible to secure an independent light source 12 fitted in each optical bl a reflector 13.

The device according to the invention, which is entirely modular and therefore simple to produce and implement, can be manufactured to a large extent using commercial composites, which has a very favorable effect on cost. The invention is not limited to the embodiment described above but embraces all the variants, in particular the following:

- It could be conceived that the video image cutting unit associated with each liquid crystal unit is incorporated within it. Thus, the electronic interface of this liquid crystal unit and its image cutting unit could be produced within a single integrated monolithic component.

The term video here denotes a composite video signal or else a signal obtained for example from three color signals such as red, green, blue, or even, more generally, any signal capable of generating an image having or not having color potential. ; this color potential can also be present within the signal without being exploited at the image level.

Although the invention finds its full interest with large screens comprising several modules, it is clear that the proposed device can also be used with a single module in certain cases.

Of course, some of the means described above can be omitted in the variants where they are not used.

Claims

claims

1. Device for displaying an image on a screen of the type comprising

processing means for drawing an opti image from a signal such as a video signal (7), and

- means (16) based on optical fibers (16 for transferring said optical image to the screen (in particular with anamorphosis,

characterized in that

the means of treatment include:

. image cutting means (9), suitable for receiving the video signal (7), and for delivering a plurality of so signals (SS), relating to disjoi and complementary subsets of the image,

a plurality of liquid crystal display units (15), receiving respectively the sub-signals (S), and

. means (12, 13) for illuminating the liquid crystal windows (150) of said units, from the rear, and substantially white light, in order to define there so images,

and in that the anamorphic means (16) are arranged to transfer with magnification said sub-ima on the large screen (E) cut into homolo sections in the shape of the windows of the liquid crystal units.

2. Device according to claim 1, characterized in that the lighting means comprise a light source (12,13) for each liquid crystal unit.

3. Device according to claim 1, characterized in that the lighting means comprise a general light source (12, 13) and means (14) for distributing the light towards each liquid crystal unit.

4. Device according to one of claims 1 to 3, charac terized in that it is arranged in optical blocks each comprising a screen section, the anamorphic fiber optic (16), and the liquid crystal unit (15) provided with its electronic interface (151).

5. Device according to one of claims 1 to 4, charac terized in that it is associated with each liquid crystal unit (15) a video image cutting unit suitable for selectively erasing the image sub-assembly affect to this liquid crystal unit.

6. Device according to one of the preceding claims, characterized in that it further comprises a general management unit (10), for controlling the image cutting means.

7. Device according to one of the preceding claims characterized in that the anamorphic means (16) com take a bundle of optical fibers (163) secured by a resin on the side of the liquid crystal unit and, at the opposite, held in a two-dimensional step chosen in the rear vicinity of a frame (161) supporting a section of the screen.

8. Device according to claim 7, characterized e what it includes means forming an optical coupler between the liquid crystal unit and the associated fibers

9. Device according to one of claims 7 and characterized in that it comprises means forming a filter and / or optical diffuser at the fiber outlet on the screen section.