DE2924101A1 - MULTICOLOR IMAGE PROJECTION SYSTEM - Google Patents

Description

PATENT ADVOCATE DIPLtING. PAUL DIEHL LIETZENBURGER STRASSE 53 1OOO BERLIN 15 CALL (030) 8 82 20 63/8 82 20 64

- f - ■

June 11, 1979 D / Ke

Ing.Michael Stolov

25, Hapoel Street

Herzlia

Nof-Yam, Israel

Multi-color image projection system

909882/0712

Multi-color image projection system

The invention relates to a multicolor image projection system, that is a large, bright and clear projection of colored, changing and / or moving images or images by means of an electronic technology that allows a very low energy consumption of this electronic circuit guaranteed. In particular, the present invention discloses the possibility of very much to create large Plüssig-Kristall projection screens with high information capacity that are suitable for one very quick switching and also suitable for multiple display.

The present invention provides the ability to produce extremely large, bright and clear moving images in both black-and-white and color reproduction, using only simple and cheap techniques Need to become. The invention can be used both for advertising purposes and for creating the background of theater stages, in cinema and television studios as well as on screens for the digital and also graphic Playback in computer systems can be used in place of traditional cathode ray tubes. According to the present invention, an electronically controlled filter can be used to detect multicolored to obtain digital images in conventional facilities, with an extremely low energy consumption is required. According to the invention, a very large liquid crystal wall is obtained for the first time for images, which is suitable for quick switching and also for multiple display. The above

909882/071 2

- Λή '

mentioned advantages are according to the invention by the The following structure of the system is achieved: A light source, a liquid-crystal device, which is so arranged is that it is struck by the light coming from the light source, a multitude of electrodes, which are functionally linked to the liquid crystal device, a device by means of which individual The electrodes can be energized to select areas of the liquid crystal device to make transparent, a projection screen and a lens system, by means of which that through the liquid crystal device stepping light is thrown onto the projection screen.

Further features of the invention are specified in the subclaims.

Various exemplary embodiments of image projection systems according to the invention are shown schematically in the drawing shown, on the basis of which the invention is explained in more detail below. Show it:

Fig. 1 is a schematic front view of a first embodiment of an electronically controlled Color or gray filter, as it is within an image projection system according to the invention can be used,

Fig. 2 shows the details reproducing section through the filter according to Fig. 1 in the through the Line Y-Y marked plane on an enlarged scale,

909862/0712

3 shows the top view of a colored mask of the controllable liquid-crystal information carrier color filter, which can be used within the system according to the invention,

4 shows the plan view of the counter electrodes of a second type of liquid crystal information carrier color filter, which is suitable to be used within the system according to the invention,

5 shows the front view of a grid wall which is also part of a color filter and is circular is,

6 shows a liquid crystal information carrier together with an electronically controlled one Color filter that is illuminated by an external light source using a mirror,

7 shows the front view of an electronically controlled slide,

8 shows the side view of a device within which a liquid information carrier grid wall together with an electronically controlled color filter and an electronically controlled one Gray filters are assigned to one another in a manner according to the invention,

9 shows an image projection system which produces particularly bright and clear color images from a small Liquid crystal information carrier wins and

© 09882/0712

Throws on a large flat projection screen according to the present invention,

Fig.10 an image projection system, by means of which bright and sharp, multicolored images of three separate little plush-crystal walls a large screen is projected,

Fig. 11 a very large electronically controlled slide, which consists of an arrangement of numerous very small liquid crystal cells are made up and used for multiplication suitable, and

Fig. 12 shows the relationship between the passage of light by a liquid crystal information carrier and the frequency of the applied voltage.

It will first be the preferred embodiment of FIG Invention, as shown in Figure 9, explained in more detail. Then there is the projection system according to the invention from a large transparent or reflective screen 48, a lens 47, a liquid crystal information carrier grid wall 46, made of a sheet of frosted glass or translucent plastic existing element 45 or a correspondingly suitable lens, an electronically controlled color filter 44, a bright light source 43, a reflection mirror 42 and a motor-driven fan 49.

909882/0712

The light coming from the light source 43 comes together with the one reflected by the reflection mirror 42 Light component through the electronically controlled color filter 44, the color of which can be changed if necessary can. A particularly suitable embodiment for the color filter for the purposes of the present invention 44 is explained in more detail below. The light that passes through the filter 44 is colored then passes through the frosted glass pane 45, which is also called a translucent plastic pane can be present, or by a suitable lens, and is thereby scattered, so that the light is present in uniform brightness. This uniform luminous flux illuminates the transparent liquid crystal information carrier grid wall 46. The downstream lens 47 enlarges and projects the representation or the image that comes from the grid wall 46, on the big screen 48. The blower or fan 49 is needed to set the correct temperature of the Liquid crystal information carrier wall 46 and des Color filter 44 maintain. The wall 46 may, for example, be a conventional alpha-numeric or Seven segment type of liquid crystal information carrier be. Such information carriers can be used to display data information on medium-sized screens of computers and the like in place of conventional complicated systems using of cathode ray tubes. Other possible applications are display systems in which very large image umbrellas are used. It can be pictures, moving as well as stationary, stationary or themselves changing data is projected. For enlarged

§09882 / 0712

Graphic images can be used instead of the liquid-crystal information carrier wall 46 according to FIG. In this case "m" means the number of horizontal horizontal strip elements on one liquid crystal information carrier wall and "n ^tf the number of vertical narrow strips on the other wall, both walls mutually overlapping.

7 shows another exemplary embodiment of a grid wall using a liquid crystal information carrier. The front glass wall of the liquid crystal information carrier 7 carries electrodes in the form of vertical narrow strips that connect to the connecting lines 21 to 36 are equipped, while the rear glass counter electrodes in the form of narrower carries horizontal strips, which are equipped with the connecting lines a to i. In practice it will of course, a considerably larger number of electrodes depending on which one is desired Resolving power used. The grid wall is usually opaque. When a tension is on for example a vertical front segment, e.g. to the connection line 26, and to a horizontal counter electrode, For example, is placed on the connection line c, a point on the grid wall, which in Fig. 7 with marked with an x, transparent, and the light, that comes from the light source 23 can pass through this point χ, but not through any other point of the grid wall. The fact that now a desired group by electronic addressing

809882/0712

4b

When voltage is applied to various points, the user can generate graphical representations and images. The grid wall according to Fig. 4, when used together with the enlargement system according to Fig. 9, represents a new component that can be referred to as an electronically controlled valve (ECS).

5 shows a further embodiment of an electronically controlled slide according to the present invention Invention. In this case the grid wall has a circular shape. The front electrodes are narrow sectors while the counter-electrodes represent narrow concentric rings, the division also being made the other way round can be. This electronically controlled circular slide valve (ECS) provides an image that is directed to a bright large screen can be projected enlarged and is useful in many cases.

Another new ingredient included in the scope of the invention System is used particularly advantageously, is an electronically controlled color filter, the together with the controlled slider offers the user the option of a colored, bright and clear graphic To win an image on a screen, in particular a very large projection screen.

Two special forms of training the new controllable filter are presented for the first time in the present application disclosed. The initial design of the filter is very simple and can be done with a very simple electronic Circuit operated. This filter is only suitable for playing back data. An execution

909882/0712

example of this filter is shown in Figs.

According to Fig.2, the new color filter consists of the two Glass plates 11 and 13, which are held at a distance from one another in the frame 12, with between these two Glass plates 11 and 13 a liquid crystal 14 is arranged. The front plate 13 carries electrodes in the form a corresponding number of narrow vertical strips 1, 2, 3 and 4 (see also Fig.l), while the rear Plate 11 with a corresponding number of counter electrodes 16, which are also in the form of vertical narrow strips are formed facing the front electrodes of the plate 13 is equipped. The on the front plate 13 located electrodes 1 to 4, which can be clearly seen from Fig.l, are four Groups connected to one another, this mutual linkage both within the plate 13 as well can be outside the same. The electrodes 1 are, for example, all connected to the connecting line 5, the electrodes 2 with the connecting line 6, the electrodes 3 with the connecting line 7 and the electrodes 4 to the connecting line 8. All of the counter electrodes 16 are open together with the connecting line "BP" of the glass plate 11 are connected to one another and to the liquid crystal 14. On the one facing away from the light source The surface of the glass plate 13 is, at a distance from the liquid crystal 14, as FIG. 2 shows, a striped one Color filter 15 arranged. A front view of this striped color filter 15 is shown in FIG. It deals is a thin layer composed of four groups of colored strips that are transparent.

909882/0712

292-101

The stripes with the designation "R" are red, the stripes with the reference letter "G" are gray, the stripes of the "B" group are blue and those of the "W" group are whitish. The colored stripes exactly cover the electrodes 1 to 4 of the liquid-crystal information carrier according to Pig.l. In the de-energized state, this wall is impermeable to light. However, if a voltage is applied to the connection line "P" and one of the connection lines 5 to 8, one of the groups of strips R _} g, B or W becomes transparent. If, for example, a voltage is applied to the electrode BP and the connecting line, then all the strips 2 become transparent. In this case the light can only pass through the green stripes. A field of green-n luminous stripes appears. The frosted glass pane 10 or a similarly acting diffusing element distributes the light evenly over all surface components. 1 and 3 it can be seen that a voltage on the connection line 5 results in red light, a voltage on the connection line 7 results in blue light and a voltage on the connection line 8 results in white light. It is possible to get a total of 13 different colors by mixing the red, green and blue colors together with the white saturation color.

for example, red and white result in pink, etc. According to Fig.2 a second frosted glass pane or a similarly light-dispersing element 10a is provided to a to get uniform white light before it reaches the color filter.

In Figure 6, an embodiment is shown, within which the first-mentioned embodiment of the

909882/0712

292A101

-yf-

Color filter 18 together with a conventional seven-segment liquid crystal information carrier 20 is used, which is activated by external reflected light. The external light, e.g. daylight, is transmitted through reflects the mirror 17, then passes through a controllable color filter 18 and receives the desired color filter there Colour. After this light has passed the second frosted glass pane 19, it becomes uniform and illuminates the liquid crystal information carrier 20.

This arrangement can be used in facilities such as wall-mounted meters or counters, Clocks, etc. The other design of the filter is obtained when the colored mask according to FIG according to Fig. 7 covers exactly. In this case it is after the vertical and horizontal electrodes 21-36 as well as being addressed electronically a - j possible to control the colors of all surface sections optionally and independently of each other. In this case, the resolution of the color filter is about four times lower than that of the Grid wall, but this resolution is sufficient for color images. The second training of the controllable Color filter can be used within wide limits, but it requires a considerable effort in the associated electronic control.

Another embodiment of a filter that can be used within the system of the invention can, represents the electronically controlled neutral density filter (EGGF), which is obtained when in the embodiment According to Fig. 3, instead of the four colored stripes, four groups of gray filters with four different

909882/0712

292A101

different shades of gray can be used. A mixture of the four gray groups allows the user to to obtain thirteen different shades of gray.

In Fig.4 an arrangement is shown within of which a controllable grid plate 41 together with a frosted glass pane 40, a controllable color filter 39 and a controllable neutral density filter 38 is used. The light source 37 is also provided. This device allows the user to display art images and illustrations in all possible colors on a bright and to get large screen if they functionally have a projection screen and a lens, for example the screen 48 and the lens 47 according to Fig. 9 is assigned. The corresponding to the art pictures or illustrations Information can be held in electronic stores held or recorded on tapes or records. However, such information can also be obtained from a radio station can be received, which also sends audio signals such as music at the same time. the Thus, the present invention provides both a visual art and a data information display technique.

The previous description with reference to the associated Figures related only to a few exemplary embodiments and variants of one according to the invention Furnishings. Numerous other embodiments are conceivable within the scope of the invention.

For facilities of professional use, within which a very high color resolution is necessary,

909882/0712

the projection system can be modified, as shown in FIGS. 10 and 11.

The projection system according to FIG. 11 contains a large one Screen 65, three lenses 62, 63 and 64, three identical liquid crystal information carriers 50, 51 and 52, three color filters 53, 54 and 55 of the colors red, green and blue and three light sources 56, 57 and 58 each with the associated reflectors 59, 60 and 61, all three liquid crystal information carriers 50, 51 and 52 have the same grid and are precisely at the same point within the 65 screen is focused. The composite sections of the image that appear in red color are selected by the fact that the liquid crystal wall 50, behind which a red filter 53, the consists of a red transparent glass or plastic disc, is connected to voltage. It goes without saying even that the red filter is also in front of the liquid crystal wall 50 or even in front of the lens 62 can be arranged. The composite, mixed sections of the image, which should appear in green color, are determined by driving the liquid crystal wall 51 associated with a green filter 54, and composite portions of the image shown in blue color are to appear, by controlling the liquid crystal wall 52, to which a blue filter 55 is assigned is generated. Behind the light sources 56, 57 and 58, the reflectors 59, 60 and 61 are arranged Increase the light output of the light sources 56, 57 and 58. The light coming from the light source 56 passes through the red filter 53 and the liquid crystal wall 50.

909882/0712

- ys

The lens 62 enlarges and projects all voltage-applied portions of the liquid crystal screen wall 50 on the screen 65 in red color. The light coming from the light source 57 passes through the Green filter 54 and the liquid crystal screen wall 51. By means of the lens 63 this light is projected onto the same screen 65, so that there the green composite Sections of the image appear. The light coming from the light source 58 passes through the blue filter 55 and then the liquid crystal wall 52 and is thrown onto the screen 65 by means of the lens 64, in order to create the blue composite parts of the picture there. The mixture of the three colored light components A multicolored image with a large color resolution is produced there on the screen 65. Colored pictures can also be obtained by using only two projection devices with the colors orange and Cyan can be used. The best results are achieved with four projection devices for the colors red, green, Blue and white. If you use opaque projection elements (mirrors), reflective Liquid crystal information carriers are used. When using mirrors or prisms, the three-way projection system can be realized using only a single lens; the light output is but less.

According to the invention, a new element, the large liquid crystal information carrier (LLCD), is shown in FIG shown, which is characterized by a large information capacity and allows a tendon of Hums cha It ung. This Information carrier is made up of numerous very small ones

909882/0712

Plus-crystal cells 67-A to 67-1 assembled, whereby in practice considerably more cells are used than is shown in this exemplary embodiment according to FIG. 2. The liquid crystal cells 67-A to 67-1 are arranged on a common transparent wall, which can be made of glass or any plastic. Furthermore, all cells are connected to one another by transparent conductors, as indicated in FIG. There are of course also other connection options. The small liquid crystal cells can be used with extremely small gaps between two glass plates; this allows very short switching times to be achieved, which are particularly suitable for multiple projection. The gaps between the individual cells can be made sufficiently small that the result is that they are no longer visible from the usual distance. A particular advantage arises when the liquid crystal cells are arranged on the surface of a transparent plastic disc: this plastic disc is not fragile and can / can be produced in unlimited size, while it still does not have the well-known disturbing phenomena such as Newton's rings or discolored zones and is above it also particularly suitable for the high-speed connection, which is required when large liquid crystal walls are to be used for the multiplied display. The switching time can thereby be additionally shortened by the liquid crystal panels are up to the upper limit of its operating temperature, which is about 60-8O ⁰ C, warmed. This heating can, as indicated in Fig.10, take place by a fan that has a

909882/0712

CLH

Heating element 69 and a thermostat 70 includes. Good results can be expected if the liquid crystal walls with higher voltages, i.e. according to the n-way multiple and concatenation processes. 5

In order to project art images, such as photographs, it is very important to have a way of modulating the light intensity that should be independent of each other for all elements. According to the present Invention, this possibility is offered by a new effect within liquid crystal devices, the is shown in Fig.12. It has been found that the light intensity, across the surface of a radiating Liquid crystal device (i.e. the intensity of a reflective liquid crystal information carrier reflected light), decreases with increasing frequency of the applied voltages.

As can be seen from Fig. 12, the dependency is twofold the light output and the frequency of the applied voltage are sufficiently linear to create a liquid crystal device for the first time to be able to use it as a frequency-light intensity converter (F: L) or even as a to use an optically coupled isolator for very high output currents, with only a very low one Energy consumption by the circuits occurs. It has also been found that if one higher voltages on the liquid crystal information carrier sets the "frequency to light transmission line" shown in Fig.12 to the higher Shifts frequencies towards; this knowledge is very important for fast light modulation or multiple

909882/0712

rendering images, so it is possible to measure the intensity of the light across the liquid crystal device to modulate by changing the frequency of the applied voltage. The light can continue be modulated in that the amplitude of the applied voltage between the lower threshold value and the. Saturation level is changed, but this procedure requires a non-linear amplifier and is not as reliable as the frequency change of the applied Tension.

In a further variant, the large liquid crystal wall according to FIG. 2 can also be used without an additional transparent one Base plate 66 can be used. In this case, one of the glass panes of the liquid crystal information carrier, for example the front glass pane, which carries all the front electrodes and connections, designed as a conventional one-piece large pane of glass and only the opposing electrodes are arranged on small pieces of glass. Each individual liquid crystal element can with its individual Connections to the circuits are equipped that have a variable frequency and / or amplitude of the tensions and thereby allow very precise detailed images or images to be varied To produce brightness and clarity in different sections and / or colors of the same.

909882/0712

Claims (35)

Expectations : Multi-color image projection system, g e k e η η ζ e i c h η e t through a light source, a Liquid crystal device arranged to be affected by the light emanating from the light source is taken, a plurality of electrodes that are functionally linked to the liquid crystal device are, a device by means of which one of the electrodes is optionally applied to voltage to make selected areas of the liquid crystal device transparent, a Projection screen and a lens system, by means of which the passing through the liquid crystal device Light is thrown onto the projection screen. 2. Image projection system according to claim 1, characterized characterized in that the projection screen is very large and that of a film projector serves as the lens system. 3. image projection system according to claim 1 or 2, ge k en η ζ e ic hn e t by a motor-driven Fan for cooling the liquid crystal device. 4. image projection system according to claim 1 or 2, characterized in that the Liquid crystal device at least one electronic Contains controllable liquid crystal gray filter. 909882/0712 5. image projection system according to claim 1 or 2, characterized in that the Liquid crystal device contains at least one electronically controllable liquid crystal color filter. 6. image projection system according to claim 1 or 2, characterized in that the Liquid crystal device at least one electronically controllable liquid crystal information carrier device (display) contains. 7. image projection system according to claim 1 or 2, characterized in that the Liquid crystal device an electronically controllable color filter and a liquid crystal information carrier device which are arranged between the light source and the projection screen, the liquid crystal information carrier between the projection screen and the color filter is arranged and this color filter is in turn between the Liquid crystal information carrier and the light source is located. 8. image projection system according to claim 7, characterized in that the liquid crystal information carrier device additionally comprises an electronically controllable neutral density filter which is placed between the light source and the liquid crystal information carrier device lies. / Π7 1 3 9. image projection system according to claim 7, characterized in that the electronically controllable color filter a liquid crystal device with a number of electrodes in the form of narrower Comprises stripes extending over at least the greater part of the surface of the liquid crystal device; and including at least one colored stripe, and further including a light diffuser is arranged between the color filter and the light source. 10. Image projection system according to claim 9, characterized characterized in that the light diffusing means from a frosted glass pane, which can also consist of PlastiJcma4e_rial, or a Condenser lens exists. 11. Bildprojektioßs system according to claim 7, characterized marked that this is electronic controllable color filter comprises a liquid crystal device, the electrodes in the form of narrow strips on at least the greater part of the surface of this liquid crystal device, on the a layer of colored stripes with the colors red, green, blue and white is attached, with one also Light diffusion device between this color filter and the light source and between the color filter and the liquid crystal device is.
30th 12. Image diffusion system according to claim 11, characterized characterized that the light distortion anoan ^ / ni 1 9 . - " : Scattering device as a frosted glass pane, which can also consist of plastic material, or as a condenser is trained. 13. Image projection system according to claim 1 or 2, characterized in that the liquid crystal device is an electronically controllable Contains neutral density filter and a liquid crystal information carrier between the light source and the Projection screen is arranged, this liquid crystal information carrier between the projection screen and the neutral density filter and the neutral density filter in turn lies between the liquid crystal information carrier and the light source is arranged. 14. Image projection system according to claim 13, characterized characterized in that the electronically controllable gray filter is a liquid crystal device comprises, which has electrodes in the form of narrow strips on the greater part of its surface, wherein furthermore a layer of gray stripes of different shades of gray is provided and furthermore between the gray filter and the light source light scattering elements are arranged. 15. Image projection system according to claim 14, characterized characterized in that the light scattering device is designed as a frosted glass pane is. 16. Image projection system according to claim 1 or 2, characterized in that the liquid crystal device consists of an electronic controllable liquid crystal grid wall in circular shape with an m: n matrix, which consists of m-electrodes is defined in the form of narrow strips and by n-electrodes in the form of narrow concentric rings and the nm electrodes are arranged on opposing surfaces of this grid wall. 10 17. Image projection system according to claim 1 or 2, characterized in that the light source comprises a mirror which produced this Light reflected on the liquid crystal device. 18. Image projection system according to claim 1 or 2, marked by a device that supplies voltages to the electrodes, each of which correspond to certain dates. 19. Image projection system according to claim 18, characterized characterized in that the data input device includes electronic storage devices contains. 20. Image projection system according to claim 18, characterized characterized in that the data input device comprises a magnetic tape player consists. 909802/0712 21. Image projection system according to claim 18, characterized in that the data input device consists of a record player. 22. Image projection system according to claim 18, characterized characterized in that the data input device comprises a radio receiver which is designed so that it receives signals from at least can go out, receive and demodulate a radio station. 23. Image projection system according to claim 1, characterized by a plurality of Light sources, a correspondingly large number of liquid crystal devices so arranged are that they can be acted upon by the light of the light sources, a correspondingly large Number of filters of which at least two allow light of different color to pass through to appropriate To be able to color light rays, each of which is to pass through the liquid crystal device and originating from the light sources, a projection screen and a projection device, the Emits rays of light that pass through the liquid crystal device and the color filters in order to reach the To get to the projection screen. 24. Image projection system according to claim 23, characterized in that the projector device consists of three projection devices that project in the colors red, green and blue. §09882 / 0712 _ η 25. Image projection system according to claim 23, characterized characterized in that the projector device are assigned lens systems. 26, image projection system according to claim 25, characterized ge ke nn ze i cn η et that the lens systems comprise a plurality of lenses, each lens of this plurality of lenses functionally each having one of the filters already mentioned assigned. 27. Image projection system according to claim 23, characterized g e k e η η indicates that the projection device includes four projection devices that project in the colors red, green, blue and white. 28. Image projection system according to claim 23, characterized geke nn indicate that the projection device comprises two projection devices which are shown in FIG project the colors orange and cyan. 29. Bildprojektiöns system according to claim 23, g e characterize t by a heating device for the liquid crystal element, which consists of a blower or fan and a heating element and a thermostat. 30. Image projection system according to claim 23, characterized in that the liquid crystal device is in the form of an array of individual liquid crystal cells that cover a single common transparent area are distributed. . . ".. ~ 909882/0712 31. Image projection system according to claim 30, characterized characterized in that the common transparent surface is made of plastic material. 32. Image projection system according to claim 30, characterized in that the common transparent surface one of two liquid crystal plates is, which consists of one piece, while the opposite plate is made of very small Glass parts is assembled. 33. image projection system according to claim 23, characterized by a voltage supply, connected to the liquid crystal device to make the same more variable with voltages To be able to supply the light intensity of the composite elements of the frequency To be able to change the representation or the image independently of each other. 34. Image projection system according to claim 23, characterized in that with the Liquid crystal device coupled voltage supply is designed so that it is an optically coupled isolation causes. 35. Device consisting of a liquid crystal device and a device for supply this liquid crystal device with a voltage of variable frequency to adjust either the brightness intensity the light reflection or the passage of light through the liquid crystal device to