FR2645313A1 - DEVICE FOR DISPLAYING AN IMAGE ON A SCREEN, PARTICULARLY OUTSIDE - Google Patents

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 on a screen an image, preferably capable of colors, which is visible in direct sunlight. Some applications require a large screen that can go up to a surface area of around 100 m2.

Much 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 of large dimensions, an image preferably capable of colors which is notably visible outside in direct sunlight.

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

Another object of the invention is to allow an image free of internal separation bands to be obtained.

The invention also aims to visuolisoticn outside of such an image from very wide angles.

The invention also relates to the creation of images, in particular animated images, from various sources.

 Another object of the invention is to propose such a device at a very economical price, in particular for a large part using conventional commercial components.

 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 - means driven on optical fibers, for transferring said optical image on the screen, in particular with anamorphosis.

According to a general characteristic of the invention, the processing means comprise. these 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 color 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 substantially white light, in order to define sub-images therein, provision is then made for the anamorphic means to be arranged for enlarging the transfer of said sub-images on the large screen divided into homologous sections in 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 appended drawings in which - FIG. 1 is a schematic block diagram of an embodiment of a device according to the invention, - Figure 2 schematically illustrates more particularly a part of the device of Figure li 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 may 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 the screen
E. The visualized 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 optionally processed in 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 converted into a frequency converter 50 Hertz / 60 Hertz 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 undersignals SS, relating to disjoint and complementary subsets of the image , to a modular electro-optical assembly 11. Each of these sub-assemblies is selectively managed, within the means 9, by a cutting unit 90 and a general management unit 10, such as a microcomputer, makes it possible to control the The set of cutting units 90 so as to produce various effects on the image, in particular to animate it. It is also possible, moreover, to generate alphanumeric characters on an Image background.

These image splitting means are, for example, those used in the "image wall" generation devices which came, for example, from 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 sos-signals SS is delivered to a liquid crystal color display unit 15, for example of the type marketed by the Company
CITIZEN under the reference UC 400 and / or UC 401 for NTSC video, or TC 63 for the PAL / SECAM video standard.

Such a unit conventionally comprises a liquid crystal window and an electronic interface.

Each of the windows of these display units 15 is lit by the arriaTe with substantially white light, for example from a bundle of optical fibers i4 coming from a general light source 12 equipped with a reflector 13.

By lighting this window from the rear, we come to project the sub-image corresponding to the subset of the total image, on the input of anamorphosis means 16, based on optical fibers. These optical anamorphosers have the property of transmitting this sub-image with a homothetic magnification at their exit face e which then constitutes a screen section homologous to the shape 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 section, the corresponding fiber optic anamorphoser 16 and the liquid crystal unit 15.

The operating principle of the device is then as follows. The large image displayed on 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 decorate 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 image of large dimensions, visible in particular in direct sunlight, and free of partitions or n-bands between the screen sections such as can be observed for example on the walls of 'images. 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 l inside the image, these same means here make it possible, in combination with the other means according to the invention, to obtain an image of better quality and greater visual comfort.

As illustrated in FIG. 3, an anamorphoser 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 plate, flush with the free face of which open out 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 in 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 can have a format of 32 mm x 240 mm up to 800 mm x 600 mm.

On the side of the entry face of the anamorphoser, that is to say the face opposite its exit 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 defines an entry face of dimensions 80 mm × 60 mm having a diagonal of approximately 10 mm 4 inches).

While the screen section here is simply constituted by the free outlet ends of the fibers 163 opening flush with the black piac, it is also conceivable to have on this screen section, means forming an optical filter and / or diffuser. .

The display unit 15 is secured to the anamorphic unit 16 so that the actual color liquid crystal window 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 can simply be the free entry ends of the fibers arranged opposite the window. It could also be conceived 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 to receive the sub-signals coming from the cutting means.

Although we have described above a distribution of white light from a single source by distribution means such as optical fibers, it is possible to integrate within each optical unit an independent light source 12 fitted with a reflector 13.

The device according to the invention, entirely modular, therefore of simple implementation and implementation, can be manufactured to a large extent using commercial components, which has a very favorable effect on its cost.

The invention is not limited to the embodiment described above but embraces all the variants, in particular the following one - it could be conceived that the video image cutting unit associated with each liquid crystal unit is incorporated within of 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 with or without 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 (9)

Claims 1. Device for displaying an image on a screen, of the type comprising - processing means for extracting an optical image from a signal such as a video signal (7), and - grounded means (16) on optical fibers (153), for transferring said optical image to the screen (E), in particular with anamorphosis, characterized in that  the processing means include. image cutting means (9), suitable for receiving the video signal (7), and for delivering a plurality of sub-signals (SS), relating to disjoint and complementary subsets of the image,. a plurality of color liquid crystal display units (15), respectively receiving said sub-signals (S), and means (12,13) for illuminating the liquid crystal windows (150) of said units, by the rear, and in substantially white light, in order to define subimages therein, and in that the anamorphic means (16) are arranged to carry over with magnification said subimages on the large screen (E) cut into homologous sections the shape of the windows of 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 to each liquid crystal unit. 4. Device according to one of claims 1 to 3, characterized in that it is arranged in optical units 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, characterized in that it is associated with each liquid crystal unit (15) a video image cutting unit capable of selectively managing the affected image subset 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) comprise 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 selected two-dimensional pitch, in the rear vicinity of a frame (161) supporting a section of ltécras. 8. Device according to claim 7, characterized in that it comprises means forming an optical coupling between the liquid crystal unit and the associated fIbres. 9. Dispositi according to one of claims 7 and 8, characterized in that it comprises means forming a filter and / or optical diffuser at the fiber outlet on the screen section.