WO2010145773A1

WO2010145773A1 - Image display device and corresponding operating method

Info

Publication number: WO2010145773A1
Application number: PCT/EP2010/003466
Authority: WO
Inventors: Hans-Günther NUSSECK; Heiko Schaich
Original assignee: eyevis Gesellschaft für Projektions- und Grossbildtechnik mbH
Priority date: 2009-06-17
Filing date: 2010-06-09
Publication date: 2010-12-23
Also published as: DE102009025270B4; EP2443836A1; DE102009025270A1

Abstract

The invention relates to an operating method for an image display device (1), particularly for a digital LED projector, having a plurality of varicolored light sources (2, 3, 4) generating an illuminating signal by mixing colors, wherein the operating method comprises the following steps: a) actuating the individual light sources (2, 3, 4) of the image display device (1) with prescribed color values for generating a particular color of the illuminating signal; b) checking at least one of the varicolored light sources (2, 3, 4) for functional error; c) adapting the prescribed color value of at least one error-free light source when a functional error of one of the light sources (2, 3, 4) is detected; d) actuating the individual light sources (2, 3, 4) with the adapted color values for compensating for the detected functional error. The invention further relates to a corresponding image display device (1).

Description

DESCRIPTION

Image display device and corresponding operating method

The invention relates to an operating method for an image display device, in particular for a digital LED projector. Furthermore, the invention comprises a corresponding operating method.

US Pat. No. 6,683,657 B1 discloses a digital projector which has a micromirror field as an imaging element, which is also referred to as a digital mirror device (DMD). The light source used here is a conventional lamp which emits light over a broadband range. In this known digital projector, the desired colors are generated by a rotating color wheel, which in each case transmits a specific spectral range of the light emitted by the lamp to the micromirror field, from where the light is then projected onto a projection screen by means of projection optics.

However, the lamps used here have only a limited life and can fail prematurely within the projected life for statistical reasons. Such a malfunction of the lamp then also leads to a complete malfunction of the entire digital projector.

It is therefore known from the prior art, the lamp redundant form, for example, by a reserve lamp is maintained, which can ensure the continuation of the projection operation in case of malfunction of the lamp used in normal operation. It is also known to use in such a digital projector instead of a broadband emitting lamp as light sources light emitting diodes, the narrow band light in the primary colors (eg, red, green, blue) of a color system

(e.g., RGB color system) so that the desired color of the illumination signal is produced by color mixing. The advantage of using light-emitting diodes as light sources is first of all the fact that it is possible to dispense with the above-mentioned color wheel.

A disadvantage of the use of light-emitting diodes, however, is the fact that in a functional failure of the LEDs no more images are displayed, which contain only the color of the failed LED. If, for example, an important display value or an operating state is to be displayed in red in a process control room and the red LED has failed, the corresponding display remains invisible to a viewer. In the conventional digital LED projectors so there is a risk of information loss in the event of failure of a light emitting diode.

From DE 10 2005 061 204 Al an image display device is known in which also the light of several different colors

Light emitting diodes is mixed to produce a certain color impression. In addition, it is known from this publication that intensity fluctuations of the individual light-emitting diodes are detected, which can occur, for example, as a function of the temperature or the operating time. Depending on the intensity fluctuations of the individual light-emitting diodes thus determined, the control signals for the individual light-emitting diodes are then correspondingly adapted in order to produce as unadulterated a color impression as possible. The adjustment However, measuring the color values of the individual light-emitting diodes does not serve the purpose of avoiding information loss if a light-emitting diode fails.

Furthermore, the prior art should be pointed to WO 2009/073041 Al.

The invention is therefore based on the object to avoid such information losses in the event of failure of one or more of the light-emitting diodes.

This object is achieved by an operating method according to the invention and a corresponding picture display device according to the invention in accordance with the subsidiary claims.

The invention includes the general technical teaching to check the light sources of different colors (for example light-emitting diodes, lasers) for a functional failure and to replace the color of the failed light source in the case of functional failure by the color of a functioning light source. If, for example, three light-emitting diodes in the primary colors red, green and blue of the RGB color system are present and the red light-emitting diode fails, a loss of information can be avoided when a monochrome red signal is reproduced by the green light-emitting diode and / or the blue light-emitting diode be driven to produce a color-distorted, but at least visible signal.

The operating method according to the invention initially provides in a conventional manner for the individual differently colored light sources (eg light-emitting diodes) of the image display device to be driven with predetermined color values for producing a specific color of the illumination signal, which is known per se from the prior art and therefore not closer loading must be written. The invention thus also provides that the color of the illumination signal results from a color mixing of the light signals of the differently colored light sources (eg light-emitting diodes). The resulting color of the illumination signal can be adjusted by adjusting the color values of the individual differently colored light sources accordingly.

In addition, the operating method according to the invention, however, provides that the differently colored light sources are checked for malfunction in the normal projection mode. This check can be carried out in the current projection mode, for example at certain intervals or continuously.

If the check now results in a malfunction of at least one of the light sources, then the color value of at least one of the error-free light sources is adjusted accordingly, in order to ensure a color-corrupted but at least visible display despite the functional failure. If, for example, a red arrow is to be displayed in a security-relevant process control room and the red light source has failed, the arrow can then be represented, for example, in green color, in blue color, or in a mixed color of green and blue, if the green light source and the blue light source Light source are still functional.

The individual light sources are then controlled with the correspondingly adapted color values in order to compensate for the malfunction and to avoid a loss of information.

Furthermore, it is within the scope of the invention, the possibility that at a functional failure of the different colored light sources at least one of the remaining functional Light sources flash. For example, if the red light source has failed, the blue light source and / or the green light source may flash to indicate the malfunction.

In order to check the functionality of the individual light sources, various possibilities exist within the scope of the invention, some of which are briefly described below.

One way of detecting a malfunction of the light sources is to measure an operational quantity (e.g., electric current, temperature) of the light sources and to judge the operability of the light source depending on the measured operational quantity.

For example, a malfunction of a light emitting diode is usually associated with a corresponding current drop, which allows the detection of a malfunction based on the time course of the electric current.

In addition, a functional failure of a light source usually leads to a drop in the operating temperature of the respective light source, so that it can be concluded based on the time course of the operating temperature on a malfunction.

Furthermore, it is still possible to check the functionality of the individual differently colored light sources by means of a color sensor, which is arranged in the beam path of the light sources and is used in conventional digital projectors, for example, for white balance. For example, if a red LED has failed, the illumination signal appears in the complementary color Green, which is detected by the color sensor and indicates a failure of the red LED. In the context of the invention, for example, color sensors can be used which output a color impression as an output signal. However, it is alternatively also possible that the color sensor the

Measures spectral components of the illumination signal and outputs, for example, the RGB color values.

However, the invention is not limited to the above examples in terms of checking the operability of the individual light sources. Rather, the functionality of the individual light sources can also be checked in other ways.

It was briefly mentioned above that in the event of a malfunction of one of the different colored light sources, the color values of the remaining functional light sources are adjusted. For this purpose, the color values of these functional light sources are preferably raised, so that the remaining functional light sources preferably shine more strongly or at least do not remain dark.

In addition, the color values of the remaining functional light sources are preferably adjusted only in the event of a malfunction of a light source, if the predefined color values essentially trigger only the failed light source without the error-related adaptation. If, in fact, a mixed color is to be displayed, then a malfunction of one of the differently colored light sources only leads to color falsification, but not to a loss of information. In this case, then no adjustment of the color values is required. This is only the case if the currently displayed color matches the color of the failed same source of light or very similar in terms of their wavelength.

It should also be noted that the invention does not have regard to the type of light sources of different colors

Light-emitting diodes is limited. For example, laser projectors are also known in which differently colored lasers are used as light sources.

It should also be mentioned that the color system used for color mixing the illumination signal does not necessarily have to be an RGB color system. Rather, it is also conceivable that in the context of the invention, a different color system is used, such as the CMYK color system (CMYK: cyan, magenta, yellow, key = black).

When using the invention as part of a digital projector, the actual image is preferably generated by a digital image converter, which is illuminated by the illumination signal and driven according to the desired image with a digital image signal.

The image converter is preferably the micromirror field already mentioned at the beginning of the prior art, which is also referred to as the Digital Micro Mirror Device (DMD) and which is well known from the prior art, so that in terms of structure and operation the DMD requires no further explanation.

Alternatively, however, there is the possibility that the imager has a liquid crystal display (LCD). However, the invention is not in the two types mentioned above with regard to the type of digital image converter used (DMD and LCD) limited, but in principle also with other types of image converter feasible.

Furthermore, the invention preferably provides that the image generated by the image converter is projected onto a projection screen by means of projection optics. Preferably, the projection screen is a rear projection screen, i. the projection and the viewing take place here from opposite sides of the rear projection screen. However, within the scope of the invention, it is alternatively possible for the image to be viewed and projected from the same side of the projection screen.

In the use of a color sensor briefly mentioned above, the illumination signal generated by the light sources is preferably split by a beam splitter into two sub-beams, one sub-beam being directed at the image converter while the other sub-beam is directed at the color sensor. Such beam splitters are known per se from the prior art and therefore need not be described in detail.

In addition to the operating method according to the invention described above, the invention also includes a novel image display device, in particular a digital LED projector, which is suitable for carrying out this operating method. For this purpose, the image display device according to the invention has a control unit which activates the individual light sources with predetermined color values in order to achieve a desired color of the illumination signal, which is also the case with conventional projectors. Preferably, each of the light sources in the control unit is assigned a separate power supply and drive unit, so that the failure of a power supply or drive unit only affects the associated light source, whereas the remaining light sources continue to function.

In addition, the image display device according to the invention has an error detection unit, which checks at least one of the light sources for a possible malfunction, in order then to be able to take the measures already described above for avoiding a loss of information.

Upon detection of a loss of function of one of the light sources by the error detection unit, the control unit then changes the color values of the remaining functional light sources in order to avoid the loss of function.

Technically speaking, the colors are processed in a chronological order. In an RGB color system, the differently colored light sources (e.g., light emitting diodes) for red, green, and blue are turned on one after the other, and then the micromirrors corresponding to that color are modulated via the imager (e.g., DMD). Now, if one of the different colored light sources fails (for example, red), then the green light source can be technically activated at the time that the red light source would actually be turned on.

The error detection unit preferably has a measuring unit for measuring at least one operating variable of the individual light sources, so that the error detection unit determines a possible malfunction as a function of the measured operating variable (for example electrical current, operating temperature).

For example, the measuring unit can each have an ammeter for the individual light sources, wherein the individual meters measure the electrical current drawn by individual light sources.

Furthermore, there is the possibility that the measuring unit in each case has a temperature measuring device for the individual light sources, with the individual temperature measuring devices measuring the operating temperature of the individual light sources.

Finally, there is the possibility that the measuring unit has the already mentioned color sensor, which measures the color composition of the illumination signal and can detect a functional failure of one of the light sources.

The aforementioned possibilities for the detection of a

Functional failure of one of the different colored light sources can optionally be used alone or in combination with each other.

Other advantageous developments of the invention are contained in the subclaims or are explained in more detail below together with the description of the preferred embodiment of the invention with reference to the drawings. Show it:

FIG. 1 shows a simplified schematic representation of a digital LED projector according to the invention,

Figure 2 shows a variant of a method according to the invention for

Detection of a malfunction of one of the light emitting diodes, the electric current being evaluated, FIG. 3 shows a modification of the fault detection method according to FIG. 2, wherein the operating temperature of the light-emitting diodes is evaluated,

Figure 4 shows a modification of the error detection method according to Figure 2, wherein the color composition of the illumination signal is measured by means of a color sensor, and

FIG. 5 shows the operating method according to the invention for avoiding a loss of information in the event of a failure of one of the light-emitting diodes.

Figure 1 shows a simplified schematic representation of a digital LED projector 1, which is largely conventional and therefore will be described only briefly.

The LED projector 1 has as light source three LEDs 2, 3, 4, the light in the three primary colors red, green,

Blue of the RGB color system radiate, with the intensity of the three LEDs 2, 3, 4 corresponding preset color values can be set to produce by color mixing an illumination signal with the desired color.

In the beam path behind the LEDs 2, 3, 4, a diffuser optics 5 and a beam splitter 6 are arranged.

The beam splitter 6 divides the incident illumination signal into two partial beams, the one partial beam being directed to a digital image converter 7 in the form of a digital mirror device (DMD), while the other partial beam is directed onto a color sensor 9 via a diffuser optics 8. The digital image converter 7 generates the actual image, which is then projected onto a projection screen 11 via projection optics 10.

The actuation of the LEDs 2, 3, 4 is carried out by a control unit 12 corresponding to the desired color of the illumination signal.

In addition, the LED projector 1 according to the invention has an error detection unit 13, which can detect a functional failure of the light-emitting diodes 2, 3, 4.

On the one hand, the fault detection unit 13 takes into account the electrical current iR, iG, iB of the individual luminous diodes 2, 3, 4, wherein the electrical currents iR, iG, iB are measured by a current measuring device 14, 15, 16. The fault detection unit 13 can then recognize from a sudden drop in the electrical current iR, iG or iB that the associated light-emitting diode 2, 3 or 4 has failed.

On the other hand, the fault detection unit 13 can measure the operating temperature TR, TG, TB of the individual light-emitting diodes 2, 3, 4. For this purpose, the LED projector 1 according to the invention has three electrical thermometers 17, 18, 19, which measure the operating temperature TR, TG or TB of the individual light-emitting diodes 2, 3 and 4, respectively. The Fehlerdetektionsemheit 13 can then detect on the basis of a drop in temperature that the associated light-emitting diode 2, 3 or 4 has failed.

In addition, the error detection unit 13 still evaluates the output signals of the color sensor 9 in order to be able to detect a malfunction of the light-emitting diodes 2, 3, 4. If, for example, the red light-emitting diode 2 has failed, the light signal measured by the color sensor 9 appears green. what the error detection unit 13 recognizes on the basis of the output signal of the color sensor 9.

In the event of failure of one or more of the LEDs 2, 3, 4, the error detection unit 13 sends a corresponding signal to the control unit 12, which then correspondingly raises the color values of the remaining functional light-emitting diodes 3, 4 in order to avoid loss of information.

In the following, the flowchart according to FIG. 2 will explain how the error detection unit 13 operates.

In a first step S1, first of all the average electric current iR is measured, which is drawn by the red light-emitting diode 2.

In a next step S2 is then checked whether the e- lectric current iR _falls below a predetermined limit IR _LIMIT .

If this is the case, it can be assumed that the red LED 2 has failed, so that in a step S3, a corresponding error flag for a malfunction of the red LED 2 is set.

Otherwise, on the other hand, in a step S4, the average electrical current iG measured by the green LED 3 is measured.

The measured electric current iG is then compared in step S5 with a predetermined limit value iG _G RENz.

If the electric current iG falls below the predetermined limit IGGRENZ, then the error detection unit 13 assume that the green LED 3 has failed. In this case, a corresponding error flag for a malfunction of the green LED 3 is then set in a step S6.

Otherwise, in a step S7, the electric current iB which is drawn by the blue light-emitting diode 4 is measured.

The measured electric current iB is then compared in a step S8 with a predetermined limit value iB _G RENz, in order to be able to detect a malfunction of the blue light-emitting diode 4.

If the comparison results in an excessively low electric current iB, an error flag for a malfunction of the blue light-emitting diode 4 is set in a step S9.

2, how the fault detection unit 13 can detect a malfunction of the light-emitting diodes 2, 3, 4 also on the basis of the operating temperature of the light-emitting diodes 2, 3, 4.

In a first step S1, the mean operating temperature TR of the red light-emitting diode 2 is initially measured for this purpose.

In a further step S2, the measured operating temperature TR is then compared with a predetermined limit value TR _LIMIT .

If now the measured operating temperature TR of the red

_LED 2 _falls below the predetermined threshold TR _LIMIT , the error detection unit 13 assumes in a step S3 that the red LED 2 has failed, whereupon the error detection unit 13 sets an error flag indicating a malfunction of the red LED 2.

Otherwise, on the other hand, the mean operating temperature TG of the green light-emitting diode 3 is measured in a step S4 and then compared in a step S5 with a predetermined limit value TGGR _E NZ.

If the predetermined limit value TG _{LIMIT is} undershot, the error detection unit 13 concludes that the green LED 3 malfunctions and, in a step Sβ, sets a corresponding error flag indicating a malfunction of the green LED 3.

Otherwise, the average operating temperature TB of the blue light-emitting diode 4 is measured in a step S7 and compared in a step S8 with a predetermined limit TB _LIMIT .

If this limit value TB _{LIMIT is} undershot, the error detection unit 13 sets in a step S9 a corresponding error flag indicating a malfunction of the blue LED 4.

4, how the fault detection unit 13 can also determine a malfunction of the light-emitting diodes 2, 3 and 4 on the basis of the color composition of the illumination signal measured by the color sensor 9.

For this purpose, the average color component R of the red LED 2 is first measured in a step Sl and compared in a step S2 with a predetermined limit value R _LIMIT . If the red color component R _falls below the predetermined limit value R _LIMIT , it can be assumed that the red LED 2 has failed, whereupon the error detection unit 13 then sets a corresponding error flag in a step S3, which constitutes a malfunction of the red LED 2 indicates.

Otherwise, on the other hand, the mean color content G of the green light-emitting diode 3 is measured in a step S4 by means of the color sensor 9 and compared with a predetermined limit value G _LIMIT in a step S5.

If the green color component G is too low, a corresponding error flag indicating a malfunction of the green LED 3 is set in a step Sβ.

Otherwise, the average color component B of the blue light-emitting diode 4 is measured in a step S7 and compared in step S8 with a predetermined limit value B _LIMIT .

If the blue color component B measured by the color sensor 9 is permanently too low, then a corresponding error flag is set in a step S9 which indicates a malfunction of the blue light-emitting diode 4.

The normal operation of the LED projector 1 will now be explained with reference to the flowchart in FIG.

In a first step S1, first the current color values R, G, B are determined with which the light-emitting diodes 2, 3, 4 are driven, the actual color values R, G, B depending on the color of the image to be displayed. In a next step S2, it is then checked whether the error flag for the red LED 2 is set.

If this is not the case, then it is moved to step S5, where the same test for the green LED 3 is performed.

Otherwise, it is checked in step S3 whether the current color values R, G, B indicate that a purely red signal is to be displayed. If this is the case, in step S4 the color values G and B for the green and blue light-emitting diodes 3, 4 are set to predetermined emergency values G _NO τ and B _NO τ, respectively, but color-falsified, but nevertheless visible Signal.

If the test in the step S5 shows that no error flag for the green LED 3 is set, the process proceeds to the step S8, where the same test for the blue LED 4 is performed.

Otherwise, it is checked in step Sβ whether a purely green signal should be displayed.

If this is the case, then the predetermined color values R and B for the red and blue light-emitting diodes 2 and 4, respectively, are set to predetermined emergency values R _NO τ and B _NO τ, respectively, in order to represent a color-falsified but nevertheless visible signal ,

If the check of the blue error flag in step S8 reveals that the blue light-emitting diode 4 has failed, then in a following step S9 it is checked whether a purely blue signal is to be displayed. If this is the case, then the predetermined color values R and G for the red or green light-emitting diode 2 or 3 are set in the step S10 to predetermined emergency values R _NO τ and G _NO τ, respectively, but a color-falsified but nevertheless visible Signal.

The invention is not limited to the preferred exemplary embodiments described above. Rather, a multiplicity of variants and modifications is possible, which likewise make use of the concept of the invention and therefore fall within the scope of protection.

LIST OF REFERENCE NUMBERS

1 LED projector

2 LED

3 LED

4 LED

5 diffuser optics

6 beam splitters

7 image converter

8 diffuser optics

9 color sensor

10 projection optics

11 projection screen

12 control unit

13 error detection unit

14 ammeter

15 ammeter

16 ammeters

17 thermometers

18 thermometers

19 thermometers

Claims

An operating method for an image display device (1), in particular for a digital LED projector, having a plurality of differently colored light sources (2, 3, 4) which produce a colored illumination signal by color mixing, the operating method comprising the following steps: a) driving the individual light sources (2, 3, 4) of the image display device (1) with predetermined color values for generating a specific color of the illumination signal, characterized by the following steps: b) checking at least one of the differently colored ones

Light sources (2, 3, 4) for a malfunction, c) adaptation of the predefined color value of at least one faultless light source upon detection of a malfunction of one of the light sources (2, 3, 4), d) activation of the individual light sources (2, 3, 4 ) with the adjusted color values to compensate for the detected malfunction.

2. Operating method according to claim i, characterized by the following steps for detecting the malfunction: a) measurement of at least one operating variable (iR, iG, iB, TR, TG, TB, R, G, B) of the individual light sources (2, 3, 4 b) detection of a malfunction of the individual light sources (2, 3, 4) as a function of the measured operating variables (iR, iG, iB, TR, TG, TB, R, G, B) of the respective light sources (2, 3, 4).

3. Operating method according to claim 2, characterized in that the operating variable measured for error detection (iR, iG, iB, TR, TG, TB, R, G, B) an electrical operating variable, in particular the electric current drawn by the individual light sources (2, 3, 4), and / or the operating temperature of the light sources (2, 3, 4).

4. Operating method according to one of the preceding claims, characterized in that a) that for detecting a malfunction of the individual light sources (2, 3, 4) the color composition of the illumination signal by means of a color sensor (9) is measured, wherein the color sensor (9) in the beam path of the light sources (2, 3, 4) is arranged, and b) that is derived from the measured color composition, whether a light source (2, 3, 4) has failed and which light source (2, 3, 4) may have failed ,

5. Operating method according to one of the preceding claims, characterized in that the color values of the non-failed light sources (2, 3, 4) are raised in case of malfunction of one of the light sources (2, 3, 4).

6. Operating method according to one of the preceding claims, characterized in that the color values of the non-failed light sources (2, 3, 4) are adapted in case of malfunction only if the predetermined color values without the error-related adjustment essentially only drive the failed light source.

7. Operating method according to one of the preceding claims, characterized in that a) that the different colored light sources (2, 3, 4) are light-emitting diodes, and / or b) that the differently colored light sources (2, 3, 4) emit light in the primary colors (R, G, B) of a color system, and / or c) that the color system has the RGB color system with the basic colors red, green and blue is.

8. Operating method according to one of the preceding claims, characterized by the following steps: a) illuminating a digital image converter (7) with the illumination signal, and b) driving the digital image converter (7) with a digital image signal for displaying the desired image.

9. Operating method according to claim 8, characterized in that a) that the image converter (7) is a digital micromirror device that generates the image by a pixel-dependent reflection, or b) that the image converter is a liquid crystal display.

10. Operating method according to claim 9, characterized by the following step:

Projecting the image generated by the imager (7) onto a projection screen (11).

11. Operating method according to one of claims 8 to 10, characterized by the following steps: a) dividing the illumination signal by a jet expensive (6) in a first partial beam and a second

Partial beam, b) directing the first partial beam onto the digital image converter (7), c) directing the second partial beam onto the color sensor (9).

12. image display device (1), in particular a digital LED projector, with a) a plurality of differently colored light sources (2, 3, 4) which produce a colored illumination signal by color mixing, b) a control unit (12) which controls the individual light sources ( 2, 3, 4) with predetermined color values in order to achieve a desired color of the illumination signal, characterized by c) an error detection unit (13) which checks at least one of the light sources (2, 3, 4) for a possible malfunction.

13. Image display device (1) according to claim 12, characterized in that the control unit (12) is connected to the error detection unit (13) and adjusts the predetermined color value in at least one of the functional light sources (2, 3, 4) when the Error detection unit detects a malfunction of one of the light sources (2, 3, 4).

14. Image display device (1) according to any one of claims 12 to

13, characterized by a measuring unit (14-19) for measuring at least one operating variable (iR, iG, iB, TR, TG, TB) of the individual light sources (2, 3, 4), wherein the measuring unit (14-19) with the Error detection unit (13) is connected, so that the error detection unit (13) in dependence on the measured operating variable (iR, iG, iB, TR, TG, TB) determines a possible malfunction.

15. Image display device (1) according to claim 14, characterized in that a) that the measuring unit (14-16) in each case has an ammeter for the individual light sources (2, 3, 4), wherein the individual ammeters (14-16) see the electrical current (iR, iG, iB) the individual light sources (2, 3, 4) measure, and / or b) that the measuring unit (17-19) each have a temperature measuring device for the individual light sources (2, 3, 4), wherein the individual temperature measuring devices (17-19) measuring the operating temperature (TR, TG, TB) of the individual light sources (2, 3, 4), and / or c) that the measuring unit has a color sensor (9) which measures the color composition of the illumination signal.

16. Image display device (1) according to any one of claims 12 to 15, characterized in that a) that the different colored light sources (2, 3, 4) are light-emitting diodes, and / or b) that the different colored light sources (2, 3, 4) light in the basic colors of a color system, and / or c) that the color system is the RGB color system with the primary colors red, green and blue.

17. Image display device (1) according to any one of the preceding claims, characterized by a digital image converter (7) which is irradiated by the illumination signal.

18. Image display device (1) according to claim 17, characterized in that the image converter (7) is a digital micromirror

Device or a liquid crystal display is.

19. Image display device (1) according to claim 17 or 18, characterized by a beam splitter (6), in the beam path between the light sources (2, 3, 4) and the image converter (7) is arranged, wherein the beam splitter (6) directs a part of the illumination signal to the image converter (7) and the remaining part of the illumination signal to the color sensor (9).

20. An image display device (1) according to any one of claims 17 to 19, characterized by a) a projection screen (11) and b) a projection optics (10) in the beam path between the image converter (7) and the projection screen

(11) is arranged and the image generated by the image converter (7) projected onto the projection screen (11).

21 image display device (1) according to claim 20, characterized in that the projection screen (11) is a rear projection screen, carried out in the projection and viewing of opposite sides of the rear projection screen.

* * * * *