DE102018121526A1 - Projection system for projecting an image - Google Patents

Abstract

A projection system with one or more digital projectors (2), each of which generates a base image and projects onto a projection surface (10) such that the base image (s) fills or fills a predetermined projection area on the projection surface, and a first additional projector ( 3), which generates a first additional image and projects it onto the projection surface (10) such that it lies in the projection area, the maximum luminous flux provided by the first additional projector (3) being greater than the maximum luminous flux provided by each digital projector (2) to thereby display at least one bright image content in the projection area.

Description

The present invention relates to a projection system for projecting an image.

Such projection systems are e.g. B. used as simulators (z. B. driving simulators for cars), for example, glare situations are to be simulated, such as those caused by the headlights of oncoming cars.
To DIN EN 12464-1 Direct glare from light sources is assessed using the CIE's “Unified Glare Rating” (UGR), which is calculated as follows: $$UGR=\mathrm{8th}\cdot {\text{log}}_{10}\left(\frac{0.25}{L_B}{\displaystyle {\sum }_{\mathrm{<figure-callout\; id="2"\; label="i\; L\; i"\; filenames="DE102018121526A1\_0012.png,DE102018121526A1\_0016.png"\; state="\{\{state\}\}">i\; </figure-callout>}}\frac{L_i}{}\frac{{}_{}{}^2{\omega }_i}{p_i{}^2}}\right)$$

L_B

Hintergrundleuchtdichte

L_i

Leuchtdichte der i-ten Lichtquelle

ω_i

Raumwinkel der i-ten Lichtquelle

p_i

Guth-Positionsindex der i-ten Lichtquelle

With

L _B

Background luminance

L _i

Luminance of the i-th light source

ω _i

Solid angle of the i-th light source

p _i

Guth position index of the i-th light source

The luminance indicates which luminous flux is emitted per surface and solid angle; the luminance is typically given in candelas per square meter (cd / m ² ).

The Guth position index p describes the sensitivity of glare as a function of the angle of the glare source to the viewing direction of the viewer. It was determined empirically and summarized in the following analytical formula (see also Ashdown, lan. (2005). Sensitivity Analysis of Glare Rating Metrics. LEUKOS The Journal of the Illuminating Engineering Society of North America. 2. 115-122. 10.1582 / LEUKOS. 2005.02.02.003): $$\begin{array}{r}\hfill p=\text{exp}\{\left(35.2-0.31889\cdot \alpha -1.22\cdot e^{-2\cdot \frac{\alpha }{9}}\right)\ast {10}^{-3}\cdot \beta +\\ \hfill \left(21.0+0.26667\cdot \alpha -0.002963\cdot {\alpha }^2\right)\ast {10}^{-5}\cdot {\mathrm{<figure-callout\; id="2"\; label="\beta "\; filenames="DE102018121526A1\_0012.png,DE102018121526A1\_0016.png"\; state="\{\{state\}\}">\beta </figure-callout>}}^2\end{array}$$

wobei L den horizontalen Abstand der Blendquelle zur Blickrichtung beschreibt und V den vertikalen Abstand; L und V sind dabei auf den Abstand zur Blendquelle normiert. Die beiden Winkel α und β werden in Grad angegeben.With tan (α) = L / V and $\text{tan}\left(\beta \right)=\sqrt{{\mathrm{<figure-callout\; id="2"\; label="L"\; filenames="DE102018121526A1\_0012.png,DE102018121526A1\_0016.png"\; state="\{\{state\}\}">L</figure-callout>}}^2+{\mathrm{<figure-callout\; id="2"\; label="V"\; filenames="DE102018121526A1\_0012.png,DE102018121526A1\_0016.png"\; state="\{\{state\}\}">V</figure-callout>}}^2}.$

where L describes the horizontal distance of the glare source to the viewing direction and V the vertical distance; L and V are standardized to the distance from the glare source. The two angles α and β are given in degrees.

The criteria for glare are then given as follows (see Ashdown, lan. (2005). Sensitivity Analysis of Glare Rating Metrics. LEUKOS The Journal of the Illuminating Engineering Society of North America. 2. 115-122. 10.1582 / LEUKOS.2005.02. 02.003 or https://docs.agi32.com/AGi32/Content/adding_calculation_points/Calculations_UGR_Concepts.htm). Table 1 (Criteria for glare depending on the “Unified Glare Rating” (UGR)): UGR Criterion of psychological glare (Discomfort Glare Criterion) 10 imperceptible 13 Just perceptible 16 perceptible 19 Just acceptable 22 not acceptable (unacceptable) 25th Just uncomfortable 28 uncomfortable 31 Just intolerable

Daraus resultiert nach (2) ein Guth-Positionsindex von p ≈ 1.03.This results in a glare source that is 50 m apart, 2 m to the side and 0.5 m in height from the viewing direction $\alpha =\text{arctan}\left(\frac{2m}{50m}/\frac{0.5m}{50m}\right)\approx 80°\text{and}\beta =\text{arctan}\left(\sqrt{{\left(\frac{2m}{50m}\right)}^2+{\left(\frac{0.5m}{50m}\right)}^2}\right)\approx 2.4°,$

According to (2), this results in a Guth position index of p ≈ 1.03.

A headlight with a diameter of 15 cm appears to the viewer at a distance of 50 m at a solid angle of $\omega =2\pi \ast \left(1-\text{cos}\left(\frac{15cm}{50m}/2\right)\right)\approx 7\cdot {10}^{-6}sr,$

On a country road, there is an ambient luminance of around L _B = 0.03cd / m ² at night.

If the headlamp produces a luminance of L = 3200cd / m ² , then equation (1) gives UGR ≈ 22. According to Table 1, glare from such a headlamp is "unacceptable", ie no longer accepted from the comfort perception.

The same glare source at a distance of 20 m produces a UGR ≈ 28 ("uncomfortable"; here is p ≈ 1.08). If it has a luminance of L = 1330 cd / m ² , it is no longer accepted (UGR ≈ 22).

The formulas were originally derived for interior lighting, but have been applied to street scenes here.

Scenes are typically displayed in a simulator with the aid of an arrangement of several digital projectors (depending on the requirement, for example between two and 20). However, it is only possible to reproduce the actual brightness levels with considerable effort, since in digital projection luminance levels of 1330 cd / m ² , as mentioned in the above example as glare source, can only be achieved with extremely high effort. Rather, the maximum luminance in a simulator with digital projectors is of the order of 50 cd / m ² . This is the maximum luminance that a glare source can produce.

The example above shows that the digital projection technology must have a high contrast or rather a high dynamic range (in the example of the light source of 1330 cd / m ² this is more than 100 000: 1 against the background of 0.03 cd / m ² ). In the prior art, therefore, projectors with a high dynamic range are used - so-called HDR projectors. However, an estimate according to equation (1) shows that for glare sources at a distance of 20 m with L = 50cd / m ² a background luminance of L _B = 4.24 · 10 ^-5 cd / m ^{2 is} required in order to achieve a glare of UGR ≈ 22 produce; the required contrast here is beyond one million to one.

so ergibt sich für die Darstellung der Hintergrundleuchtdichte eine Grauwert von g_B ≈ 0.44. Offensichtlich ist dies mit einem 8bit-Projektions-System nicht möglich. Selbst ein 10bit-System kann eine solche Hintergrundleuchtdichte gerade so darstellen (da der kleinste von Null verschiedene Grauwert - umgerechnet auf eine Skala von 0 bis 255.75 - bei 0.25 liegt). Da man zusätzlich den Bildinhalt, der die Hintergrundleuchtdichte aufweist, auch noch modulieren möchte, um eine Szene darstellen zu können, wird offensichtlich, dass HDR-Projektionssysteme mit 8bit oder 10bit nicht geeignet sich, um Blendsituationen mit UGR ≈ 22 darstellen zu können.Based on a projector that displays image information in 8 bits (gray values 0, 1, ... 255) with a y = 2.2 (the gamma value describes the non-linear mapping of the digital input data to the brightness values generated from it) $$L\left(G\right)=L\left(255\right)\ast {\left(\frac{G}{255}\right)}^{\gamma }$$

this results in a gray value of g _B ≈ 0.44 for the display of the background luminance. Obviously, this is not possible with an 8-bit projection system. Even a 10-bit system can display such a background luminance (since the smallest non-zero gray value - converted to a scale from 0 to 255.75 - is 0.25). Since you also want to modulate the image content, which has the background luminance, in order to be able to display a scene, it becomes obvious that HDR- Projection systems with 8bit or 10bit are not suitable to be able to display glare situations with UGR ≈ 22.

In these considerations it was assumed that the projection system follows equation (3) perfectly and thus has an infinitely high contrast. In reality, only the best systems (which are implemented, for example, via double modulation) have contrasts of more than one million to one and are therefore able to produce brightness levels that can be distinguished down to gray level 0.5. Standard projectors with a contrast of 2000: 1, on the other hand, according to equation (3), cannot already distinguish brightness differences below gray level 8.

The observations made show that a simple HDR projection is not suitable for simulating glare situations in a simulator.

• Durch Verwendung eines zusätzlichen Projektors, der die gleiche Leuchtdichte erzeugt, wie der eigentliche Bild-Projektor (im Beispiel 50cd/m²) kann die maximale Leuchtdichte L, die für eine Blendung zu Verfügung steht, verdoppelt werden. In diesem Beispiel (bei Abstand 20m) ergibt sich nach den Gleichung (1) und (3), dass der Bildinhalt des Hintergrundes einen mittleren Grauwert von g_B ≈ 0.8 aufweisen muss, um Blendsituationen mit UGR ≈ 22 darzustellen. Wie oben bereits diskutiert wurde, ist ein solcher Grauwert über eine 8bit-Projektion nicht darstellbar; bei einer 10bit-Projektion verbleibt keine Modulationstiefe für eine Darstellung von Strukturen im Hintergrund. Die Lösung ist also nicht praktikabel um reale Blendsituationen darzustellen.

In order to still be able to generate high luminance locally via digital projection, which can lead to glare, it is possible to use additional projectors. These only project image content where glare sources are to be expected - typically in the direction of travel of an auto simulator:

• By using an additional projector that produces the same luminance as the actual image projector (in the example 50cd / m ² ), the maximum luminance can be achieved L available for glare can be doubled. In this example (at a distance of 20m) it follows from equations (1) and (3) that the image content of the background must have a mean gray value of g _B ≈ 0.8 in order to represent glare situations with UGR ≈ 22. As already discussed above, such a gray value cannot be represented by an 8-bit projection; with a 10-bit projection there is no modulation depth for displaying structures in the background. So the solution is not practical to represent real glare situations.

Proceeding from this, it is the object of the present invention to provide a projection system for projecting an image, with which the difficulties mentioned at the outset can be overcome as completely as possible.

The invention is defined in claim 1 and in claim 10.

Advantageous refinements are specified in the dependent claims.

With the projection system according to the invention, z. B. variable (colors, geometries) realistic glare situations with extensive glare or a variety of glare sources (z. B. wet road).

The projection system according to the invention can have a plurality of digital projectors, the base images, which are also referred to below as partial images, preferably partially overlap in order to be able to generate a larger overall projected image or to be able to fill a larger projection area. Furthermore, the projection system according to the invention can have a plurality of additional projectors which provide a maximum luminous flux which is greater than the maximum luminous flux of the at least one digital projector and which each generate a further additional image and project it so that it is in the predetermined projection range. All additional images of the additional projectors preferably overlap at least 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80% or 90% of the area of the predetermined projection area. The overlap can in particular be chosen such that there is only an overlap where bright image content is to be displayed.

It is also possible for at least two additional images to overlap partially or completely.

Due to the higher maximum luminous flux of the first additional projector compared to each of the digital projectors, the number of additional projectors required can be minimized in order, for. B. to represent glare situations without using other light sources. The luminous flux of a projector describes the radiation that the projector emits in the form of visible light; the luminous flux is typically given in "lumens".

The increase in luminous flux can e.g. B. done via a limitation of the displayable color space. In a special case, the first additional projector can only display a single color. Ideally, this color is similar to the colors that are supposed to create glare; So in the case of car headlights, white tones.

With digital projectors that display the colors sequentially, a large part of the light from the light source of the digital projector is not used. This is necessary in order to be able to display the required color space. For this purpose, z. B. "Cut out" spectral ranges using a color wheel, which lead to the desired color locations for red, green and blue, so that time-sequential red, green and blue color partial images can be generated. The color partial images are generated and projected so quickly in succession that an observer can no longer resolve the color partial images in time and thus can only perceive the overlay as a multi-colored partial image.

If you want to use such a digital projector as the first additional projector, the maximum luminous flux or maximum light output provided can be increased by modulating the complete light of the light source without first splitting it spectrally via color filters. In the case of color sequential imaging, this can e.g. B. done by omitting the color wheel.

In the case of a digital projector with three imagers (one each for red, green and blue), an additional projector can be derived from this by restricting oneself to a pure white projection. All that is required is an image generator that modulates all of the light from the light source (without spectral splitting into the three color channels). In this case, the maximum luminous flux of the additional projector is increased (due to the small number of optical elements, each of which only transmits 99% of the light). Furthermore, the additional projector becomes simpler and less expensive since two image generators and components for color splitting can be dispensed with.

It is advantageous to use both the at least one digital projector and the first additional projector to display the glare source, since an even brighter glare can be generated by the sum of the resulting luminances. The control unit of the projection system, which distributes the image information to the individual projectors, can thus distribute the image information of the glare source to the associated digital projector and additional projectors.

The color of the additional projector may not match the color that the dazzling light source should have. It is advantageous here that the control unit distributes the image information to the at least one digital projector and the first additional projector in such a way that the desired color location of the glare source is created in the superimposition of the two images. This makes it possible to gain brightness depending on the color to be displayed, which results in the possibility of performing glare on the UGR scale. The achievable UGR values are significantly higher than when using another digital projector (with full color space) as a projector for generating a glare effect according to the prior art.

In order to further increase glare, it is advantageous to reduce the image field (and thus the size of the first additional image on the projection surface) of the first additional projector (and possibly further additional projectors) or to select it so that it is smaller than an image field one of the digital projectors or that it is smaller than any image field of all digital projectors.

Furthermore, it is possible, as an additional projector, to only reduce the selectable color space or to select it to be smaller than that of at least one of the digital projectors. For color sequential imaging, the transmission areas of the color filters (e.g. in the color wheel) are broadened spectrally. In this case, the achievable maximum luminous flux of such an additional projector does not increase as high as in the case of a pure white projector as described above (), but the colors that should cause glare can be adjusted more flexibly.

The color space can also be reduced by using only two colors (e.g. blue and yellow) instead of three primary colors (red, green, blue) for the first additional projector. In the case of a digital projector with a color wheel, this can be achieved using a color wheel with the corresponding color segments.

When using LEDs or lasers as light sources (or other light sources that are not white but colored), several colors can be switched on at the same time. For example, the maximum luminous flux in the green can be increased if a red and blue light source is also switched on at the same time (possibly with less power); this also leads to a reduction in the color space.

The first additional projector can generally display fewer colors than the at least one digital projector, but is much brighter, so that with fewer projectors in a projection system, glare can be achieved in the predetermined projection area, since the image fields of the additional projectors do not have to be reduced so much. This makes the entire projection system cheaper and less complex.

The color space which can be represented by means of the (first) additional projector is preferably smaller than the color space which can be represented by means of the at least one digital projector. Smaller is understood here in particular to mean that the area in the color space is smaller by 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80% or 90%.

Each digital projector can have a flat modulator with a plurality of independently controllable pixels. In the same way, the first additional projector and each additional additional projector can have a planar modulator with a plurality of pixels that can be controlled independently of one another. Furthermore, it is possible for each of the projectors to have two planar modulators connected in series with a plurality of pixels which can be controlled independently of one another, the two modulators being mapped onto one another in order to thereby provide a better contrast ratio. Each flat modulator can be reflective or transmissive. In particular, each flat modulator can be designed as an LCD module or as a tilting mirror matrix. A planar modulator can therefore also be referred to as a two-dimensional imager. The pixels can be arranged in rows and columns, for example.

Furthermore, each digital projector can have its own light source. In the same way, the first additional projector (and each additional additional projector) can have its own light source. The light source can be a light source that emits white light. It is also possible for the light source to be designed as a laser, LED, ...

The projection system according to the invention can have a control unit for controlling the projectors.

In the projection system according to the invention, the color of a bright image content can be achieved by combining the representation in at least one of the basic images and in the additional image. The two projectors therefore do not represent the same color, so that the correct color is only generated in the overlay.

The control unit of the projection system can thus divide the image information for the bright image content into the at least one digital projector and the (first) additional projector in such a way that the predetermined brightness and color of the image information only result from the superimposition of the projected basic image and the projected (first) additional image .

The bright picture content does not have to be white, but can be of any color.

For example, the (first) additional projector can have a color wheel with brilliant color, the color segments for the primary colors being shortened, so that fewer bit levels are available for modulation. To do this, a white segment (and / or yellow segment) is significantly enlarged, which means that more light is available. Alternatively, fewer primary colors can be used in the color wheel, for example, in order to be able to provide a larger white segment, which in turn leads to more light.

The (first) additional projector can also be a single color. This enables the maximum light output of the light source of the (first) additional projector.

The image sizes (sizes of the (first) additional image) of the (first) additional projector can be smaller than the image sizes of the basic image (s), since the resulting maximum luminance of the (first) additional projector will be even higher. Since in the application of the bright image content as glare, such glare only plays a role close to the direction of view of the user (due to the Guth position index according to equation 2), the number of additional projectors additionally required is not too high.

It is advantageous if the brightness of the first additional projector or the additional projectors can be dimmed. This can be done, for example, via an iris diaphragm, which can reduce the light from the illumination (or light source) that is directed onto the image generator. Additionally or alternatively, this can be realized by controlling the light source of the corresponding additional projector. For this purpose, for example, the current, the voltage and / or the pulse width can be used to control the light source. In addition or as an alternative, dimming can also take place via a shutter in the beam path. The shutter can light the z. B. block all or part. Each of the additional projectors, the brightness of which can be dimmed, thus has a dimming device by means of which the brightness of the corresponding additional projector can be dimmed. Because of the finite contrast of the (first) additional projector, this advantageously leads to the fact that the image is not brightened by the black level of the (first) additional projector in dark scenes in which glare should not occur.

To avoid damage to the eyes of the people in a simulator in which the projection system according to the invention is used, it can be monitored that the glare (for example rated in UGR) does not exceed a predetermined threshold. For this purpose, for example, the displayed image content in a certain image region is “averaged” over a certain time, around the current adaptation of the eyes (to an average background luminance L _B ) to investigate.

It goes without saying that the features mentioned above and those yet to be explained below can be used not only in the specified combinations but also in other combinations or on their own without departing from the scope of the present invention.

• 1 eine schematische Ansicht eines ersten Ausführungsbeispiels des erfindungsgemäßen Projektionssystems 1;
• 2 eine Draufsicht auf das Farbrad 8 des Digitalprojektors 2 von 1;
• 3 eine Draufsicht auf die Projektionsfläche 10 zur Erläuterung der Überlagerung des ersten Teilbildes B1 mit dem ersten Zusatzbild Z1 im vorbestimmten Projektionsbereich P des erfindungsgemäßen Projektionssystems 1 gemäß 1;
• 4 eine Darstellung gemäß 3 eines weiteren Ausführungsbeispiels des erfindungsgemäßen Projektionssystems 1;
• 5 eine Darstellung gemäß 3 eines weiteren Ausführungsbeispiels des erfindungsgemäßen Projektionssystems 1;
• 6 das normierte Spektrum der Lichtquelle 5 des Digitalprojektors 2 von 1 ;
• 7 die Transmissionskurven der Farbsegmente R, G und B des Farbrades 8 von 2;
• 8 die gemeinsame Transmissionskurve der Beleuchtungs- und Projektionsoptik 6, 7 sowie die Reflektivität des Modulators 4 des Digitalprojektors 2 von 1;
• 9 die Normfarbtafel des Bild-Projektors 2 von 1;
• 10 den Helligkeitsgewinnfaktor für den Blend-Projektor 3 von 1;
• 11 eine Ausschnittsvergrößerung des Helligkeitsgewinnfaktors gemäß 10;
• 12 die erzielbare Blendung (in UGR) bei Verwendung des Blend-Projektors 3 von 1 in Abhängigkeit der Farborte;
• 13 die erzielbare Blendung (in UGR) bei Verwendung eines weiteren bekannten Bild-Projektors;
• 14 die erzielbare Blendung (in UGR) mit einem Blend-Projektor 3 gemäß 1 und einem 1,6fach kleineren Bildfeld;
• 15 die erzielbare Blendung (in UGR) bei Verwendung eines weiteren bekannten Bildprojektors mit einem 1,6fach kleineren Bildfeld;
• 16 ein weiteres Ausführungsbeispiel des erfindungsgemäßen Projektionssystems 1;
• 17 Filterkurven für das Farbrad 16 des Blend-Projektors 3 gemäß 16;
• 18 die Normfarbtafel des Blend-Projektors 3 gemäß 16; und
• 19 eine weitere Ausführungsform des Bild-Projektors 2 des erfindungsgemäßen Projektionssystems.

The invention is explained in more detail below on the basis of exemplary embodiments with reference to the accompanying drawings, which likewise disclose features essential to the invention. These exemplary embodiments are only illustrative and are not to be interpreted as restrictive. For example, a description of an exemplary embodiment with a large number of elements or components should not be interpreted to mean that all of these elements or components are necessary for implementation. Rather, other exemplary embodiments can also contain alternative elements and components, fewer elements or components or additional elements or components. Elements or components of different execution examples can be combined with one another, unless stated otherwise. Modifications and modifications, which are described for one of the exemplary embodiments, can also be applicable to other exemplary embodiments. To avoid repetitions, the same or corresponding elements in different figures are given the same reference numerals and are not explained several times. From the figures show:

• 1 is a schematic view of a first embodiment of the projection system according to the invention 1 ;
• 2 a top view of the color wheel 8th of the digital projector 2 of 1 ;
• 3 a top view of the projection surface 10 to explain the overlay of the first sub-picture B1 with the first additional picture Z1 in the predetermined projection area P of the projection system according to the invention 1 according to 1 ;
• 4 a representation according to 3 a further embodiment of the projection system according to the invention 1 ;
• 5 a representation according to 3 a further embodiment of the projection system according to the invention 1 ;
• 6 the normalized spectrum of the light source 5 of the digital projector 2 of 1 ;
• 7 the transmission curves of the color segments R . G and B of the color wheel 8th of 2 ;
• 8th the common transmission curve of the lighting and projection optics 6 . 7 as well as the reflectivity of the modulator 4 of the digital projector 2 of 1 ;
• 9 the standard color chart of the image projector 2 of 1 ;
• 10 the brightness gain factor for the blend projector 3 of 1 ;
• 11 an enlarged detail of the brightness gain factor according to 10 ;
• 12 the achievable glare (in UGR) when using the blend projector 3 of 1 depending on the color locations;
• 13 the achievable glare (in UGR) when using another known image projector;
• 14 the achievable glare (in UGR) with a glare projector 3 according to 1 and a 1.6x smaller image field;
• 15 the achievable glare (in UGR) when using another known image projector with a 1.6x smaller image field;
• 16 a further embodiment of the projection system according to the invention 1 ;
• 17 Filter curves for the color wheel 16 of the blend projector 3 according to 16 ;
• 18th the standard color chart of the blend projector 3 according to 16 ; and
• 19 another embodiment of the image projector 2 of the projection system according to the invention.

At the in 1 shown embodiment includes the projection system according to the invention 1 a first digital projector 2 and a first additional projector 3 ,

The first digital projector 2 has a modulator as an imager 4 , the z. B. is designed as a tilting mirror matrix, a light source 5 (which emits white light, for example), lighting optics 6 and projection optics 7 on. The modulator 4 becomes the light source with light 5 illuminated by a color wheel 8th ran. The color wheel 8th z. B. a red, green and blue color segment R . G . B on how in 2 is shown schematically, and is about its axis 9 rotated so that the modulator 4 is illuminated sequentially with red, green and blue light. The modulator 4 modulates the red, green and blue light one after the other by means of the independently controllable tilting mirror of the modulator 4 in order to generate color partial images of a first partial image (or first basic image) by means of the projection optics 7 on a projection screen 10 projected and can only be perceived by a viewer together as a first colored partial image. The modulation is done by a control unit 11 based on supplied image data BD controlled so that a desired brightness and color are achieved for each pixel.

The normalized spectrum of the light source 5 is in 6 shown and 7 shows the transmission curves of the color segments R . G . B of the color wheel 8th , The common transmission curve of the lighting and projection optics 6 . 7 as well as the reflectivity of the modulator 4 are in 8th shown.

The division of the red, green and blue segments / color segments is 41%, 29% and 30%, respectively, so that there is a color space and a white point WP, as in 9 is shown. For a conversion of spectra to color coordinates, DIN EN ISO 11664-1 or on the statements in the DE patent application No. 102017115092.7 directed.

In Table 2 below, the in 9 drawn in color locations of the primary colors as well as white for the first digital projector 2 compiled, with the X, Y, Z coordinates standardized to Y _white = 1 and also the color locations x . y and a normalized luminance L are specified. Table 2: red green blue White X 0.4053 0.3453 0.1873 0.9379 Y 0.2194 0.7395 0.0412 1 Z 0.0053 0.0658 0.9916 1.0628 x 0.6433 0.3001 0.1535 0.3126 y 0.3482 0.6427 0.0337 0.3333 L 0.219 0.739 0.041 1

The first additional projector 3 is designed as a digital projector that does not have a color wheel. The rest of the structure corresponds to that of the first digital projector 2 so that the first additional projector 3 (also referred to below as a blend projector 3 is referred to as an image generator a modulator 12 , the z. B. is designed as a tilting mirror matrix, a light source 13 , lighting optics 14 and projection optics 15 having.

The first additional projector 3 creates an additional image on the screen 10 is projected so that the first additional image at least partially overlaps the first, colored partial image. As a result, the projected image of the projection system according to the invention lies on the projection surface 10 in front.

In the exemplary embodiment described here, the image sizes or image fields of the first partial image are B1 of the first digital projector 2 and the first additional picture Z1 of the first additional projector 3 on the projection surface 10 same size and completely overlap as in 3 is shown schematically. The first drawing file B1 completely fills a predetermined projection area P on the projection surface 10 out.

As will be described in the following exemplary embodiments, the size of the first additional image can Z1 on the projection surface 10 be smaller than the size of the first field B1 , as in 4 is shown. This fills the first drawing file B1 the predetermined projection area P on the projection surface 10 again completely out. The first additional picture Z1 lies within the predetermined projection range P and thus also within the first field B1 ,

If, as described below in the exemplary embodiments, next to the first digital projector 2 yet another digital projector provides a second field B2 generated and projected, that with the first field B1 partially overlapped, as in 5 is shown, the first additional image Z1 , which in turn lies in the predetermined projection range, which is now through the two partial images B1 and B2 is formed or executed, as in 5 is shown, each partial image only partially overlap.

In the projection system according to the invention 1 is the at least one digital projector 2 necessary to create the desired image. Basically, the additional projector 3 be omitted without z. B. less image information is displayed. The first additional projector 3 (or also other additional projectors) are provided to ensure bright image content within the predetermined projection range P to be able to generate in the representation. For example, simulation applications can be used to simulate glare or glare effects.

$${\left(x,y,L\right)}_{Blend-Projektor}=\left(\mathrm{0.3043,0.3410,3.6637}\right)$$

The first additional projector 3 can only project a “color”. It results (if the achievable luminance is standardized to that of the first digital projector 2 same image size): $${\left(X.Y.Z\right)}_{Blend-PrOjektOr}=\left(\mathrm{3.2702.3.6637.3.8114}\right)\text{respectively}\text{,}$$

$${\left(x.y.L\right)}_{Blend-PrOjektOr}=\left(\mathrm{0.3043,0.3410,3.6637}\right)$$

The first additional projector 3 has a maximum luminous flux of approximately 3.66 times that of the first digital projector 2 , which is also called image projector below.

If one considers a glare situation as described at the beginning (glare source with a diameter of 15 cm at a distance of 20 m, 2 m to the side and 0.5 m in height), then analogously to the calculations carried out in the prior art, this results in a average gray value of g _B ≈ 1.8 is required for the background luminance (compared to 0.8 according to the prior art). For a 10-bit projection system, there are 7 modulation levels (0.25, 0.5, 0.75, 1.0, 1.25, 1.5 and 1.75) compared to 3 (0.25, 0.5 and 0.75) in the prior art.

If you demand 10 modulation levels (average gray value of at least 2.5), the image field must be at the first additional projector 3 can only be reduced by a factor of 1.6 (compared to factor 6 in the prior art). This leads to significant cost savings and reduced complexity of the simulator system.

In the previous exemplary embodiment, the considerations were carried out on the basis of the luminances which can be achieved. The colors used for glare were not taken into account.

• Die vom erfindungsgemäßen Projektionssystem 1 dargestellte Farbe und Helligkeit einer Blend-Region ergibt sich aus der Summe der Farbkoordinaten (X, Y, Z)_{Bild-Projektor}, die vom Bild-Projektor 2 erzeugt werden, und des Blend-Projektors 3 (X,Y,Z)_{Blend-Projektor}. Im einfachsten Fall werden beide Projektoren 2, 3 bei maximaler Helligkeit betrieben: Für den Bild-Projektor 2 ist dies die Projektion von Weiß mit (X,Y,Z)_Weiß = (0.9379,1,1.0628) (vgl. Tabelle 2), beim Blend-Projektor 3 wird dies über (X,Y,Z)_{Blend-Projektor} = (3.2702, 3.6637, 3.8114) erzielt. Daraus ergeben sich Blend-Farbkoordinaten mit $$\begin{array}{ccc}{\left(\begin{array}{c}X\\ Y\\ Z\end{array}\right)}_{Blendung}& ={\left(\begin{array}{c}X\\ Y\\ Z\end{array}\right)}_{Bild-Projektor}& +{\left(\begin{array}{c}X\\ Y\\ Z\end{array}\right)}_{Blend-Projektor}\end{array}$$
  
  zu (X,Y,Z)_Blendung = (4.2082,4.6637,4.8742) bzw. (x,y,L)_Blendung = (0.3061,0.3393,4.6637). Der resultierende Farbort (x,y) liegt also zwischen dem für Weiß des Bild-Projektors 2 und dem des Blend-Projektors 3.

In this exemplary embodiment it is now shown that with the aid of a blend projector 2 according to 1 also have different blend colors realized:

• The projection system according to the invention 1 The displayed color and brightness of a blend region results from the sum of the color coordinates (X, Y, Z) of the _{image projector} , that of the image projector 2 generated, and the blend projector 3 (X, Y, Z) _{blend projector} . In the simplest case, both projectors 2 . 3 operated at maximum brightness: For the image projector 2 this is the projection of white with (X, Y, Z) _white = (0.9379,1,1.0628) (see Table 2), for the blend projector 3 this is achieved via (X, Y, Z) _{blend projector} = (3.2702, 3.6637, 3.8114). This results in blend color coordinates $$\begin{array}{ccc}{\left(\begin{array}{c}X\\ Y\\ Z\end{array}\right)}_{BlendunG}& ={\left(\begin{array}{c}X\\ Y\\ Z\end{array}\right)}_{Bild-PrOjektOr}& +{\left(\begin{array}{c}X\\ Y\\ Z\end{array}\right)}_{Blend-PrOjektOr}\end{array}$$
  
  to (X, Y, Z) _glare = (4.2082,4.6637,4.8742) or (x, y, L) _glare = (0.3061,0.3393,4.6637). The resulting color locus (x, y) is between that for the white of the image projector 2 and that of the blend projector 3 ,

If you want to create a glare of a different color (with a different color location (x, y)), you can do this by adjusting the color in the image projector 2 be carried out and, if necessary, by changing the brightness of the blend projector 3 : $$\begin{array}{ccc}{\left(\begin{array}{c}X\\ Y\\ Z\end{array}\right)}_{BlendunG}& =\left(\begin{array}{rrr}\hfill X_r& \hfill X_G& \hfill X_b\\ \hfill Y_r& \hfill Y_G& \hfill Y_b\\ \hfill Z_r& \hfill Z_G& \hfill Z_b\end{array}\right)\cdot {\left(\begin{array}{c}r\\ G\\ b\end{array}\right)}_{Bild-PrOjektOr}& +w\cdot {\left(\begin{array}{c}X\\ Y\\ Z\end{array}\right)}_{Blend-PrOjektOr}\end{array}$$

Here are r, g, b, w ∈ [0.1] and describe how much light from the red, green and blue channels of the image projector 2 or how much light from the blend projector 3 is used.

The values can be derived from this equation for a given color locus (x, y) r . G . b and w for which the luminance L becomes maximum: L _{max glare} (x, y). If you set this brightness to the maximum brightness L _{max image} (x, y) of the image projector 2 for a given color locus (x, y) in the ratio, the result is a brightness gain factor of $$F\left(x.y\right)=\frac{L_{\text{Max}BlendunG}\left(x.y\right)}{L_{\text{Max}Bild}\left(x.y\right)}$$

In 10 it is shown which brightness gain factors are for the presented blend projector 3 surrender. The brightness gain factor is shown depending on the color locus (x, y) for which glare is to be achieved. The contour train with the factor 1 corresponds to the edge of the color space that with the image projector 2 can be represented.

11 shows a section of the color space for which the highest profit factors are achieved. These are in the range of the white points of the image and glare projector 2 . 3 ,

If one transfers the gain in brightness to a projection system according to the invention 1 with a maximum luminance of 50 cd / m ² for an image projector 2 and simulates a headlight with a diameter of 15 cm at a distance of 20 m, laterally offset by 2 m and 0.5 m in height (analogous to the considerations from the prior art) with a background luminance corresponding to a gray level of 2.5 (allows a modulation of 10 gray levels for 10-bit projectors), the UGR values for a glare situation can be determined using formula (1). It shows up in 12 , which is the achievable glare (in UGR) when using a blend projector 3 depending on the color loci (x, y) shows that with a blend projector 3 according to this embodiment, UGR values of up to 19.5 let achieve. This is significantly more than when using another image projector 2 would be possible (cf. 13 , which shows the achievable glare (in UGR) when using another image projector to generate glare depending on the color locations (x, y); here the maximum is UGR = 13.6.

Reduce the image size of the blend projector 3 additionally by a factor 1.6 , the values of the color coordinates (X, Y, Z) _{blend projector} also by a factor 1.6 greater. If these values are used in equation (5), the brightness gain factors can again be determined using equation (6). The UGR values for a glare situation can also be determined using formula (1). It shows up in 14 that with a blend projector 3 according to this exemplary embodiment, UGR values of more than 22 achieve what is perceived as unacceptable glare according to Table 1. 14 shows the achievable glare (in UGR) when using a blend projector 3 depending on the color loci (x, y), whereby opposite 12 one by a factor 1.6 smaller image field of the blend projector 3 was accepted. For a projection system 1 , where another image projector with 1.6 times smaller image is used for glare, only UGR values up to 15.4 produce; such glare is only perceptible (see Table 1 or 15 ). 15 shows the achievable glare (in UGR) when using another image projector to generate glare depending on the color locations (x, y), whereby opposite 13 one by a factor 1.6 smaller image field of the additional image projector was adopted. Reduce the image size of the blend projector 3 further, glare with UGR ≥ 22 can be achieved for other colors.

An increase in the luminous flux that can be achieved for a blend projector 3 can in a development of the projection system according to the invention 1 , in the 16 is shown, can be generated by restricting the color space that can be displayed. In 17 are filter curves for a color wheel 16 of the blend projector 3 shown opposite the filter curves of the image projector 2 transmit significantly more light (cf. 7 ). The color space that can be displayed is in 18th shown, which is significantly smaller than that of the image projector 2 (see. 9 ). For the color wheel 16 of the blend projector 3 red, green and blue segments of 32%, 40% and 28% are assumed, so that the resulting white point is (x, y) = (0.3122,0.3318) and that of an image projector 2 from embodiment according to 1 equivalent. However, the resulting maximum luminous flux L is by a factor 1.77 higher than that of an image projector 2 , A blend projector 3 according to the embodiment presented here offers a lower gain in the maximum achievable luminous flux; however, he can more easily create glare situations for colors that are closer to the primary colors.

In 19 is a possible training for the image projector 2 shown, the same or similar elements of the image projectors described so far 2 with the same reference numerals and to avoid repetition reference is made to the above statements. The image projector 2 according to 19 differs from the image projector described so far 2 in that it has two optically connected modulators 4 and 17 which has a lens 18th or lens optics 18th and a mirror 19 are mapped onto each other. Such training with two modulators connected in series 4 . 17 leads to a higher contrast ratio, which is particularly the case when using the projection system according to the invention 1 is often desired in simulators.

Such training with two modulators connected in series 4 . 17 is of course also for the blend projector 3 applicable. In this case, only the color wheel 8th be omitted or designed so that it can represent a smaller color space with a higher luminous flux.

Incidentally, the DE 10 2008 029 789 A1 as well as the DE 10 2016 100 592 A1 referenced, in which the structure of digital projectors with one or two series-connected modulators is described in detail. The content of these two publications is hereby incorporated here.

QUOTES INCLUDE IN THE DESCRIPTION

This list of documents listed by the applicant has been generated automatically and is only included for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• DE 102017115092 [0055]
• DE 102008029789 A1 [0079]
• DE 102016100592 A1 [0079]

Non-patent literature cited

• DIN EN 12464-1 [0002]
• DIN EN ISO 11664-1 [0055]

Claims (10)

Projection system with one or more digital projectors (2), each of which generates a base image (B1, B2) and projects onto a projection surface (10) in such a way that the base image (s, B1, B2) has a predetermined projection area (P) on the projection surface (10) fills or fill, and a first additional projector (3), which generates a first additional image (Z1) and projects onto the projection surface (10) such that it lies in the projection area (P), the one from the first additional projector (3 ) provided maximum luminous flux is greater than the maximum luminous flux provided by each digital projector (2) in order to thereby display at least one bright image content in the projection area (P). Projection system according to Claim 1 , in which the digital projector (s) each project their base image so that it has a predetermined size, and the first additional projector (3) projects the first additional image so that it has a predetermined size, the predetermined size of the first Additional image is smaller than the predetermined size of at least one of the projected basic images. Projection system according to Claim 1 or 2 , in which at least one digital projector (2) is designed such that it generates and projects the basic image (B1, B2) in multiple colors, the first additional projector (3) is configured in such a way that it generates and projects the first additional image (Z1) in multiple colors, wherein the color space of the first additional projector (3) is smaller than the color space of the at least one digital projector (2), which generates and projects the basic image in multiple colors. Projection system according to one of the above claims, in which at least one digital projector (2) has a planar modulator (4) with a plurality of independently controllable pixels and the first additional projector (3) has a planar modulator (12) with a plurality of independently controllable pixels Has pixels. Projection system according to one of the above claims, in which at least one digital projector (2) has its own light source (5) and the first additional projector (3) has its own light source (13). Projection system according to one of the above claims, in which at least two digital projectors are provided which generate and project the basic images in such a way that they only partially overlap. Projection system according to one of the above claims, in which the first additional projector (3) has a dimming device with which the brightness of the first additional projector (3) can be dimmed. Projection system according to one of the above claims, in which at least one additional additional projector is provided which generates a further additional image and projects it onto the projection surface (10) such that it lies in the projection area (P), the maximum provided by the additional additional projector (3) Luminous flux is greater than the maximum luminous flux provided by each digital projector (2) in order to thereby display at least one bright image content in the projection area. Projection system according to one of the above claims, in which a control unit (11) is provided for controlling the projectors (2, 3) based on supplied image data (BD), the control unit (11) controlling the projectors (2, 3) in such a way that the predetermined color of the bright image content is only achieved by superimposing the base image or images and the additional image or images. Projection method in which with one or more digital projectors (2) each generates a base image (B1, B2) and will project onto a projection surface (10) such that the base image (s, B1, B2) has a predetermined projection area (P) on the Fills or fill projection area (10), and a first additional image (Z1) is generated with a first additional projector (3) and is projected onto the projection surface (10) in such a way that it lies in the projection area (P), the maximum luminous flux provided by the first additional projector (3) being greater than the maximum luminous flux provided by each digital projector (2), in order thereby to display at least one bright image content in the projection area (P).

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