Projection Display

Abstract

The invention relates to a projection display with at least one light source (l), which has at least one complex (2) consisting of at least two optical individual channels (K), each of which is formed from a respective area light modulator (D) which influences the light propagation direction pixel-by-pixel and an optical element (0), and it applies for all channels of the complex that the entire over-all optical elements of all channels illuminate the area light modulator (D) upon light incidence on the complex (2), so that the optical element (0) of said channel images the light reflected in the area light modulator (D) as an object structure, and the imaging of all the individual channels is superimposed on a screen (3) into one or more virtual or real overall images.

Description

[Technical field]

[0001] The present invention relates to a projection display having at least one light source and regularly arranged optical channels. In particular, the present invention relates to a digital projection system based on a reflective pixelated area light modulator (digital micro-mirror device, DMD). [Background technology]

[0002] It is known to realize the projection of static and dynamic image contents onto a screen using slide projectors or projection displays with an imaging channel or three imaging optical channels for color mixing or by means of laser scanners. The miniaturization required for use, for example, as a mobile image generation system, here leads to a certain brightness loss of the projected image.

[0003] Possible areas of application for the present invention are therefore in communication and maintenance electronics, data visualization, spectrometers, 3D printers and also in the automotive field, especially for interior lighting and for automotive exterior lighting, e.g. headlights.

[0004] From US 2006 / 0285078 A1, color-sequential LED-illuminated picoprojectors are known, but their miniaturization is only possible to a limited extent due to the limitations of the transmittable light flux due to small surfaces. This relationship is dictated by the fundamental optical law of etendue conservation. Real optical systems increase the etendue or reduce the system transmittance. For a minimum transmittable light flux in the projection optical system, a required minimum object surface is therefore also required. In single-channel projection systems, due to optical laws with the surface to be imaged (natural vignetting, imaging errors), the system structure length increases as well, which makes miniaturization difficult. With the proposed new approach of the array projector, this dependency between the projection brightness and the system structure length is overcome.

[0005] An alternative concept for radically miniaturizing projection systems is the scanning laser projector, where the image content is generated by scanning a power-modulated laser beam across the image plane, as described in US20080265148. The brightness achievable with this approach is limited, among other things, by the poor performance of available single-mode lasers or by their limited modulation possibilities. A further substantial drawback is the speckle structure that limits the achievable resolution in the projected image.

[0006] DE 10 2009 024 894 A1 relates to a projection display with at least one light source and regularly arranged optical channels. The optical channels include at least one field lens, to which an object structure to be imaged and at least one projection lens are respectively assigned. The distance between the projection lens and the assigned object structure corresponds to the focal length of the projection lens, whereas the distance between the object structure to be imaged and the assigned field lens is selected such that a Köhler illumination of the assigned projection lens is possible. A superposition of the individual projections on the overall image is then performed.

[0007] DE 10 2010030138 A1 describes a system comprising at least one light source (110), at least one reflective image generator (120) configured to display identical individual images in a two-dimensional distribution (122) of partial areas (124), and an image plane (150) in which the assigned partial areas (125) of the at least one image generator (120) are respectively configured to image the individual images in such a way that the imaging of the individual images corresponds to a total image (124) in the image plane (150). A projection display (100) is known which comprises a projection optics array (130) having a two-dimensional array (132) of projection optics (134) superimposed on a projection optics array (130) of a reflective image generator (120) and at least one beam splitter (140) arranged in the optical path between the at least one reflective image generator (120) and the two-dimensional array (132) of projection optics (134) on the one hand and between the at least one light source (110) and the at least one reflective image generator (120) on the other hand.

[0008] A further projection display with an image generator is described in DE 10 2011 076 083 A1, which is configured to generate individual images in a distribution, such as a two-dimensional distribution, of partial areas of the image generator's image plane, and further comprises a multi-channel optics, which is configured to image each assigned individual image or assigned partial area of ​​the image generator per channel, in particular so that the imaging of the individual images is at least partially superimposed on the overall image in a projection plane, which projection plane is, for example, a non-flat free-form surface, such as a curved surface, and / or is inclined with respect to the image plane, and further the image generator may be arranged such that the arrangement of points in the partial images, which are respectively superimposed by the multi-channel optics on respective common points in the overall image, differs depending on the distance of the respective common points in the overall image from the multi-channel optics. Alternatively, the image generator and the multi-channel optics are configured such that the prominence of the contribution of each channel to the overall image varies locally across the overall image depending on the distance of the respective common points in the overall image from the multi-channel optics.

[0009] According to the solution from DE 10 2013208625 A1, images to be projected using a multi-aperture projection display can be generated at different projection distances, in particular not statically or mechanically without respective switching or in an image generator-side manner, but by appropriately designing the individual images of the multi-aperture projection display, i.e. by combining preliminary individual images for a projection channel of the multi-aperture projection display, which are provided for each of the at least two images to be projected, into an actual or final individual image for each projection channel.

[0010] According to current prior art, digital projection systems use a spatial light modulator (SLM), which modulates the light incident on it to generate information containing an image, which can then be imaged by an optical array or directly directed onto a screen, as in the case of laser scanning systems.

[0011] Each optical projection system is characterized by the luminous flux it can emit. The luminous flux F of a single-channel projection system is EKP is now directly proportional to the square of the focal length of the projection objective (with respect to the slide surface A, the luminance of the light source B, the system transmittance T, the aperture number F of the projection optics and the paraxial focal length f MKP ) the following formula:

number

[0012] A multi-channel projection system according to the model of DE 10 2009 024 894 A1 avoids this dependency by using a two-dimensional array of projection channels. The luminous flux F of this type of system of a multi-channel projector MKP is the following formula:

number

number

[0013] Therefore, to be able to transmit the same light flux, a multi-channel projector with, for example, 100 or 10x10 projection channels needs only one tenth of the focal length of a single-channel projector, which allows for considerable space-saving possibilities, since the structural length of the projector is directly correlated to the focal length of the projector. Summary of the Invention [Problem to be solved by the invention]

[0014] The object of the invention is to propose a digital projection display which achieves a hitherto unattainable combination of light intensity, compactness and efficiency with a minimum number of required components. [Means for solving the problem]

[0015] This problem is solved by a projection display having the features of claim 1. The further dependent claims indicate advantageous embodiments.

[0016] The present invention describes a technical solution for the transfer of the array projection principle to a DMD (digital micro-mirror device) for modulating the light to be imaged. This technology is often also called DLP (trademark of Texas Instruments). The DMD modulates the incident light by controlled deflection using a two-dimensional matrix array of reflective pixel surfaces that can frequently exchange their bistable tilt angle between two states by individual electrical drive control. These two defined states are referred to as ON and OFF in the following. If the light that enters the DMD and is subsequently reflected by the micromirrors passes through a projection objective assigned to the DMD in the direction of a screen and is optically imaged by the optical refractive power of the projection objective, this is referred to as the ON state of the pixelated tilt mirror surface, respectively.

[0017] In the tilt mirror state OFF, the light beam is not deflected towards the corresponding projection objective lens, but is usually fed to a beam dumper, i.e. it is not used for the projected image and does not reach the screen. The DMD pixels in the current-free state (FLAT State) deflect light uncontrollably to an intermediate angle range between the ON and OFF deflection directions, typically also to a beam dumper. [https: / / www.ti.com]

[0018] The advantages of the DMD over other area light modulator technologies, such as LCD or LCoS, are its inherent high transparency based on reflection instead of absorption, its modulation capability even when using unpolarized light, and its potential to modulate light in a wide spectral range from UV through VIS to IR. -6 DMDs with pixels spaced apart by only m and a total pixel count of 1920 x 1080 pixels are commercially available.

[0019] The solution according to the present invention will be described in more detail below based on an embodiment and further based on FIGS. [Brief description of the drawings]

[0020] [Figure 1] 1 is a schematic diagram illustrating a projection display according to the present invention; [Diagram 2] FIG. 4 is a schematic diagram showing a further arrangement according to the invention; [Diagram 3] FIG. 4 is a schematic diagram showing a further arrangement according to the invention; [Figure 4] FIG. 4 is a schematic diagram showing a further arrangement according to the invention; [Diagram 5] FIG. 4 is a schematic diagram showing a further arrangement according to the invention; [Figure 6] FIG. 4 is a schematic diagram showing a further arrangement according to the invention; [Figure 7] FIG. 4 is a schematic diagram showing a further arrangement according to the invention; [Figure 8] FIG. 4 is a schematic diagram showing a further arrangement according to the invention; [Figure 9] FIG. 4 is a schematic diagram showing a further arrangement according to the invention; [Figure 10] FIG. 1 is a schematic diagram illustrating a specific embodiment of the present invention. [Figure 11] FIG. 4 is a schematic diagram showing a further arrangement according to the invention; [Figure 12] FIG. 4 is a schematic diagram showing a further arrangement according to the invention; [Figure 13] 1 is a schematic diagram showing the present invention in two different states. FIG. [Figure 14] FIG. 1 is a schematic diagram illustrating an exemplary embodiment of the present invention based on a three-channel complex. [Figure 15] FIG. 2 is a schematic diagram showing a further arrangement according to the invention supplemented by a reflector 15. [Figure 16] FIG. 1 is a schematic diagram illustrating a specific embodiment of the present invention. [Figure 16a] 2 is a schematic diagram showing the location and angle spatial distributions of a light source 1. FIG. [Figure 16b] FIG. 2 is a schematic diagram showing the location and angle spatial distributions captured in the plane of the incidence surface of the optical element facing the screen. [Figure 16c] 1 shows the spatial and angular distributions captured within the plane of the surface light modulator. [Figure 16d] FIG. 17 is a schematic diagram showing the arrangement from FIG. 16 in a three-dimensional view. [Figure 17] FIG. 1 is a schematic diagram showing the combination of two projection displays according to the present invention. [Figure 17a] FIG. 2 is a schematic diagram showing an arrangement illuminated by light source 1a in a z-view. [Figure 17b] FIG. 2 is a schematic diagram showing the arrangement illuminated by light source 1b in a z-view. [Figure 17c] FIG. 13 is a schematic diagram showing an integrated projection image of all the imaging of all the lower image halves and all the imaging of all the upper image halves. [Figure 18] FIG. 2 is a schematic diagram illustrating an exemplary overlap of two separate projected images on a screen. [Figure 19] FIG. 2 is a schematic diagram illustrating an exemplary superposition of three separate projected images on a screen. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] FIG. 1 shows, exemplarily in a y-section, a projection display according to the invention which produces a real overall image on a screen 3. Light emitted from a light source 1 is incident on a composite 2, which has the following properties: A two-dimensional i × j matrix consisting of multiple optical channels K, lying in the xy plane, with i ∈ {1, 2, 3, 4, 5, 6} and j ∈ {1, 2, 3}, with center spacing p oi and the center spacing in the y direction p oj and their matrix elements K i,j As, The following formulas respectively:

number

number

number

[0022] In the flat state of the mirror pixels of the surface light modulator, the mirror surfaces are oriented in a plane parallel to the xy plane. i,j In order to achieve the on state of all pixels of i,j is the angle α around the axis formed by the center point of the surface and the y unit vector of the system. DMD In particular, the normal vectors of the reflective pixel faces, which are oriented along the z-axis in the flat state, are now rotated so that they are inclined toward the light source. i,j In the illustrated exemplary arrangement, the channels are identical to each other. i,j and O (i+1),j is attached.

[0023] (i+1)jth optical element O (i+1)j Here, the light beam arriving from the light source 1 reaches the i,j-th surface light modulator D i,j and its adjacent channel optical element O i+1,j The optical element O is configured identically to i,j However, the surface light modulator D i,j to a real image on the screen, and all the individual channels K i,jThe individual images are arranged so as to completely overlap with the overall image on the screen 3 at a distance L1.

[0024] For large projection distances, the corresponding surface light modulator D according to the imaging equation of geometrical optics i,j Optical element O in the z direction up to i,j is the paraxial focal length f of the optical elements of the individual projection channels. MKP Shown are the main beams of the respective useful light bundles for imaging. The system is here configured as follows: i,j For each (i+1)th adjacent channel K i+1,j Only the light beam of i,j , i.e., the i-th channel row, so that the reflected light is incident on the optical element O corresponding to the planar light modulator having the row index i. i,j as a projection objective, and the optical element O i,j For optimal telecentric illumination of the i-th optical element, the light coming from the (i+1)-th optical element is focused by the surface light modulator D i,j The angle of incidence of the main beam of the light beam incident on the center point of the tilt mirror α dmd The maximum deflection angle should be twice that of the normal deflection angle (see Figure 14).

[0025] All individual channels i,j The optical axis of each individual projection of the adjacent optical element p oi and p oj and the adjacent surface light modulator p di and p dj and have a mutual focusing based on a defined center distance difference between them, which results in all the individual images on one screen 3 being completely superimposed on the overall image at a distance L1, where the following relationship is satisfied: L1=(f MKP p oi ) / (p Di -p oi)=(f MKP p oj ) / (p Dj -p oj ) holds true.

[0026] FIG. 2 shows the arrangement from FIG. 1, but instead of the main beam, shows the complete beam for the bottom pixel of the overall image in the x-direction.

[0027] FIG. 3 shows the arrangement from FIG. 1, but instead of the main beam, shows the complete beam relative to the centre point of the overall image in the x-direction.

[0028] FIG. 4 shows the arrangement from FIG. 1, but instead of the main beam, shows the complete beam for the top pixel of the overall image in the x-direction.

[0029] Figure 5 shows the arrangement from Figure 1, where instead of the on-state of all individual pixels of the surface light modulator (as shown in Figures 1-4), the normal vector of the individual mirrors is now oriented along the z-axis. In the case of a DMD, this is usually referred to as the flat state. This arrangement results in that in this pixel state, the light beam incident on the reflective surface light modulator is not imaged onto the screen 3, but falls into the beam dumper 12.

[0030] FIG. 6 shows the arrangement from FIG. 1, where instead of the previous orientation of the tilt mirrors in the on-state (FIGS. 1-4), the individual mirror surfaces are now angled clockwise from the light source at an angle 2α about the axis defined by the pixel surface center point and the y unit vector of the system. DMD The light beams are rotated by a factor of 100, which represents the off state of the individual pixels of the areal light generator. All light beams incident on the off pixels are deflected downwards even more strongly than in the flat state (see FIG. 5) and do not contribute to the imaging on the screen. To minimize scattered light, these light beams are directed towards a beam dumper 12.

[0031] 7 shows the device according to the invention according to FIG. 1 with five individual projections without mutual convergence. The individual channel projections are initially spaced apart by a distance F from the overall image on the screen 3. Makro A fixed positive focal length F Makro The light is imaged using a biconvex integrated lens 4 (converging lens) connected upstream having a lens having a convex ...

[0032] 8 shows an arrangement according to the invention according to FIG. 1 with the individual projected images emerging from the complex 2 without convergence, i.e. parallel to one another. The individual projected images enter an overall lens 5 with a variably settable focal length, which aligns the optical axes of the individual projections according to a set focal length (a negative focal length is shown in the figure), so that the individual projected images can be aligned either convergently towards the screen 3 or divergently parallel to one another. This settable focal length allows a variable image synthesis, whereby it is possible to dynamically switch between overall images with different maximum luminances and minimum numbers of pixels and minimum image sizes and overall images with maximum numbers of pixels, minimum luminances and maximum image sizes.

[0033] FIG. 9 shows an individual area light modulator D in the form of a large area composite area light modulator 6. i,j 3 shows an arrangement according to the invention, which is implemented by integrating the individual optical elements 7, 7, 7a, 7b, 7c, 7d, 7e, 7f, 7g, 7h, 7i, 7j, 7j, 7i, 7i, 7j, 7i, 7f, 7g, 7i ...

[0034] FIG. 10 shows a specific embodiment of the present invention, in which a surface light modulator D i,jThe optical elements O of the individual channels are arranged in 6 rows and j columns. i,j is formed of two lenses each having two optical surfaces. Here, the optical composite 9 is formed of two double-sided monolithic lens arrays, where the first lens array 9a is formed of the optical element O i,j The second lens array 9b includes a two-dimensional array of first lenses consisting of optical elements O i,j The surface light modulator D includes a two-dimensional array of second lenses. i,j The illumination is done by optical elements O (i+1)j By O (i+2)j It can also be done by using a surface light modulator D i,j The projection of is given by the optical element O for each channel row. i,j , for i ∈ {1, ..., 5}. Shown are the principal light paths for projections from channel rows with i ∈ {1, 3, 5}.

[0035] 11 shows an arrangement according to the invention, in which the separation of the illumination light path 13 and the projection light path 14 of the individual channels is performed by means of a monolithic prism 10. The light beam coming from the illumination source 1 is totally reflected at the side of the prism 10 due to its flat incidence angle (TIR prism) and subsequently reaches the complex 2 under oblique incidence. i,j Based on the reflection deflection and angle change of the light beam at each optical element O i,j Each light bundle which is imaged by the prism 10 into an individual projected image can be transmitted in the direction of the screen 3 through the prism 10 and further through a second prism 11, which compensates for the reflection angle deviation of the prism 10. This allows for a more compact construction compared to the arrangement of FIG. 1, since these light paths, even if they are not yet spatially separated from one another, can be fed in different directions by total internal reflection, i.e. as a function of angle, and are therefore spatially separated within the smallest construction space. All the individual projected images are completely superimposed on the overall image on the screen 3.

[0036] FIG. 12 shows the invention, in which the illumination beam bundle, unlike FIG. 11, passes refractively through the prism 10 and reaches the complex 2 without total internal reflection. i,j and the subsequent optical element O i,j Based on the imaging by , the light bundle is totally internally reflected at the interface of the prism 10 in the projection light path and is thus deflected towards the screen. Similarly in Fig. 11, the exploitation of total internal reflection as an angular filter allows a further reduction in the construction size of the overall system with respect to the arrangement from Fig. 1.

[0037] FIG. 13 shows the invention in two different states. State 1 corresponds to the projection of the actual overall image at a projection distance L1 from the complex 2, and state 2 (dashed line) shows the projection of the actual overall image at a second projection distance L2, in this case L1. <L2である。 The increase in the projection distance results from a reduction in the convergence of the individual projected images with respect to each other, which is generated by a reduction in the center distance of adjacent individual surface light modulators. Based on the possibility of electrically driving the image content of the individual surface light modulators, it is preferable to i,j This does not involve a mechanical shift of the D i,j Only by shifting the image information relative to each other above can the effective change of PDI be realized, thus generating different distances for the synthesis of the whole image.

[0038] FIG. 14 shows an example of 1,j =(D 1,j ,O 1,j ) and K 2,j =(D 2,j ,O 2,j ) and K 3,j =(O 3,j The present invention is shown based on a composite of three channels consisting of a 1000 .mu.m light source, ... and a 1000 .mu.m light source. The angle of incidence of the main beam on the area light modulator is now α DMD To form a telecentric illumination of an optical element under a tilt angle of 2α DMD It is.

[0039] Figure 15 shows the arrangement according to the invention from figure 1 supplemented by a reflector 15 in the illumination beam path, which serves to further compact the arrangement.

[0040] FIG. 16 shows a specific embodiment of the present invention. It is a five-row and three-column area light modulator D i,j The optical elements O of the individual channels are arranged in six rows and three columns. i,j Each of the optical composites 16 is formed from two lenses, each having two optical surfaces. Here, the optical composite 16 is formed from two double-sided monolithic lens arrays, where the first lens array 16a is formed from the optical element O. i,j The second lens array 16b includes a two-dimensional array of first lenses from the optical element O i,j The second lens includes a two-dimensional array of lenses from Individual surface light modulator D i,j The illumination of FIG. 10 is different from that of FIG. 10 in that the optical element O i,j and O (i+1)j , i.e. by a subset of the optical elements of the direct neighbors and the specific channel. In this arrangement, there is no cover disk 8. i,j The projection of is given by the optical element O for each channel row. i,j , for i ∈ {1, 2, 3, 4, 5}. Shown are the principal light paths for projections from channel rows with i ∈ {1, 3, 5}.

[0041] Figure 16a shows the spatial and angular distributions of the light source 1 from the arrangement from Figure 16. The light source has a rectangular shape with a relatively large spread in the x-direction and a square angular distribution with divergence angles of about ±5° in the x and y directions.

[0042] FIG. 16b shows the optical element O i,j The spatial and angular distributions of the light captured in the plane of the incidence surface facing the screen of the DMD are shown in Fig. 1. The light from the source is approximately incident on the DMD at an inclined mirror angle α DMD The optical element O at a main beam angle of -24° corresponds to twice thei,j , where i ∈ {2, 3, 4, 5, 6} and j ∈ {1, 2, 3}.

[0043] FIG. 16c shows a planar light modulator D i,j Figure 1 shows the location and angle spatial distributions captured in the plane of the DMD. Each of the 5×3 illuminated optical elements creates an image of the source's angular distribution on the DMD per channel. The main beam angle of the light bundle for the image center point is at +24° in the x direction. The tilt mirror in the on state reduces this main beam angle to 0°, i.e., D i,j The tilt mirror in the flat state redirects the main beam angle to -24°, and the pixel in the off state redirects the main beam to -48°.

[0044] FIG. 16d shows the arrangement from FIG. 16 in a three-dimensional view. Shown is a surface light modulator D 3j , where j∈{1,2,3} is the beam path of the three main beams coming from the source 1 for imaging the central point. The following beam paths: O 41 D 31 Illuminate and O 31 The beam path projected toward the screen by O 42 D 32 Illuminate and O 32 The beam path projected toward the screen by O 43 D 33 Illuminate and O 33 The beam path projected toward the screen by is shown as an example.

[0045] FIG. 17 shows a particular configuration of the solution according to the invention, in which two projection displays PD a and P.D. b The combination of PD a The PD bconsists of a light source 1b and a complex 2b. The light source 1a is connected to each of the planar light modulators D ai,j Only the lower image half 18 is illuminated (here, for example, the lower image half 19). a1,j A surface light modulator D having ai,j (The figure shows the projection display PD b D is a surface light modulator ai,j A projection display PD reflected in the yz plane shifted at the center point of a All pixels of all surface light modulators are initially formed in a flat state. a All surface light modulators in the projection display PD b Therefore, line O ai,j , where i∈{1,2,3,4,5} are used together. Therefore, the relationship between the optical elements is O a1,j ≡O b5,j and O a2,j ≡O b4,j and O a3,j ≡O b3,j and O a4,j ≡O b2,j and O a5,j ≡O b1,j For the surface light modulator, D a1,j ≡D b5,j and D. a2,j ≡D b4,j and D. a3,j ≡D b3,j and D. a4,j ≡D b2,j and D. a5,j ≡D b1,j holds true. Here, the channel-specific upper image halves 17 of all the planar light modulators are ai,j (Channel (K a1,j ) to 17 a1,j If the image contents (shown in the example in FIG. 1) are inverted, these image contents can be displayed on the projection display PD bor if the light source lb illuminates 2b, the pixels of the upper half of the surface light modulator behave as if they were not inverted, and accordingly the optical element O ai,j , for i∈{1,…,5} onto the screen in three directions. Thus, the combination of all channels, through the interaction of all optical elements and both light sources, can project the entire image with the proper distribution of illuminated and non-illuminated surfaces, under the proper modulation of the tilt mirror states. Preferably, two interlocking projection displays PD a and P.D. b In this arrangement, the technical requirements for the optical elements of each channel are relatively low, because they must now illuminate a much smaller surface area of ​​each adjacent channel or image themselves inside the channel.To avoid erroneous light in the projected image, it is advantageous to ensure a clear separation and clean connection of the illumination areas to the surface light modulator between the illumination areas coming from 1a and 1b.

[0046] Figure 17a shows the arrangement from Figure 17 in a z-direction view, illuminated by light source 1a. Shown are all 5x3 area light modulators, each illuminated in this case only in its lower half 1a. Surface elements that are active as ON pixels for light source 1a are hatched, which are displayed in black as surface elements that are active as OFF pixels.

[0047] Figure 17b shows the arrangement from Figure 17 in a z-direction view, illuminated by light source 1b. Shown are all 5x3 area light modulators, each illuminated in this case only in its upper half 1b. Surface elements that are active as ON pixels for light source 1b are hatched, which are displayed in black as surface elements that are active as OFF pixels.

[0048] Figure 17c shows the PD on Screen 3, which consists of a dark "F" in the center of a brightly illuminated square.a All lower images by half part 18 ai,j All the images of PD b All upper images by half 17 ai,j 1 shows all the images of and the integrated projected image of .

[0049] FIG. 18 shows an exemplary superposition of two individual projected images on a screen 3, which are offset from each other in the x and y directions by P / 2, respectively, where P is the distance between the surface light modulator D of the complex 2. i,j The center distance of the projected pixels is shifted as the center distance of the projected pixels. This allows the number of displayable and modulatable image pixels to be doubled in both the x and y directions, i.e., the total displayable pixels can be quadrupled. Shown are 2x2 projected pixels from the total set of all projected pixels of the individual projected images, usually several hundred pixels, in the x-direction and y-direction, respectively. This form of half-pixel overlap can be generated by adapting the spatial offset of a subset of the individual projectors. This can be generated, for example, by decentering a subset of all optical elements relative to a second subset of all optical elements. This effect, usually referred to as lens shift, on the image-side half-pixel enlargement in the x-direction and y-direction can be realized either by decentering a subset of optical elements or by decentering a subset of surface light modulators with respect to a regularly arranged array from optical elements having the same center distance from each other. Unlike conventional single-channel projection systems, which usually use high-frequency mechanisms to realize this half-pixel overlap in a time-sequential manner, a multi-channel projection system configured in this way can generate an increase in the displayable image information (super-resolution) without (solid) moving parts.

[0050] FIG. 19 shows an exemplary superposition of three individual projected images on a screen 3, which are offset from each other in the x and y directions by P / 3, respectively, where P is the number of projections of the surface light modulator D of the complex 2. i,j18, the optical axis of the first subset of optical channels is shifted by a distance of 1 / 3 pixel or 2 / 3 pixel in the angular space. This allows a factor of 3 in the number of image pixels that can be displayed and modulated in both the x and y directions, i.e. a factor of 9 in the total number of displayable pixels (super-resolution). In contrast to FIG. 18, this requires the use of a channel K whose optical axis is deflected by either a 1 / 3 pixel shift or a 2 / 3 pixel shift in the angular space with respect to the first subset of optical channels. i,j The deflection can be achieved, for example, by mutually decentering a subset of all optical elements of the surface light modulator ensemble with a uniform center distance, or by mutually decentering a subset of the surface light modulator ensemble with a same center distance.

[0051] In a particular embodiment of the solution according to the invention the paraxial focal length of the optically effective element is preferably between 0.5 mm and 30 mm.

[0052] Advantageously, in the solution according to the invention, the superposition on the screen 3 of a number of area light modulators with channel-specific spatial illumination distributions is used to achieve not only the superposition of image information on the screen, but also the D i,j It can be seen that the above involves a superposition of all the channel-specific spatial illumination distributions. The blending of light distributions resulting from this unique arrangement results in better uniformity of light distribution across the entire image compared to conventional single-channel projection systems. Conventional single-channel projection systems require a comparable uniformity of illumination of the entire image and therefore always require more effort in the construction in the illumination beam path, for example by a higher number of optical elements. Compared to a conventional projection system with the same light flux (depending on the number of channels N), the required focal length of the optical elements required for imaging is approximately

number

[0053] The dual function of the optical elements of each channel, i.e., using them both for the illumination function and for the projection function, allows for enormous component savings compared to conventional projection systems, which can lead to significantly higher performance, less faulty and lower cost projection systems due to the resulting relatively low complexity and reduced tolerance chains.

[0054] The application of the method described in DE 10 2011076083 A1 to the proposed solution according to the invention makes it possible to project contrast-rich, intensely light projection images, for example onto strongly inclined screen or freeform surfaces. The basis for this is the exploitation of the superfocus of the individual channels, which results from the multi-channel arrangement as well as from the comparatively smaller optical numerical aperture (0.5 mm...10 mm) than the usual projection distances (10 cm...10 m).

[0055] The use of the algorithms for generating object structures described in DE 10 2013 208 625 A1 can result in an extended depth of field compared to single-channel projection systems with the same light beam. In a special case, the calculation rules disclosed in DE 10 2013 208 625 A1 can be used to generate an extended depth of field compared to single-channel projection systems with the same light beam. i,j It can also be used to generate two or more projected images within a three-dimensional projection light field without the need to re-adjust the object information formed above.

[0056] For example, a surface light modulator D having 8-bit pulse width modulation drive controllable pixel brightness depth (number of gray values) i,jWhen using i·j ≡ N channels in the overall image 3, a displayable bit depth (number of displayable grayscales) of 256 × N image pixels results. This corresponds to an increase in the displayable grayscale values ​​or image depth based on the multichannel superimposed projection principle.

[0057] The exemplary embodiment illustrated in Figures 9 and 16 allows the use of optical elements as monolithic components for encapsulation of the area light generator, replacing the cover disk required in conventional projectors.

[0058] In a further particular embodiment of the solution according to the invention, within the complex 2, the projection channels K i,j A channel-specific color filter having the same transmission spectrum, e.g., red, green or blue, is assigned to a subset of the corresponding area light modulators D i,j represents the corresponding color component as an ON pixel, so that the full-color whole image is colored with the basic color for all channels K i,j It is proposed that this occurs on screen 3 due to the superposition of

[0059] By using the arrangements described in DE 102012205165 A1 and DE 2013206604 A1 in combination with the inventive arrangement disclosed in this specification, it becomes possible to project virtual image content, for example in the form of eye-tracking glasses or in the form of an arrangement for reflecting information in the field of vision of a motor vehicle occupant. The side format of commercially available DMD surface light modulators is often 16:9, and for the realization of an efficient projection system it is advantageous to use optical elements with apertures whose format also corresponds to 16:9 or 1:1, which results in optimal surface light modulator area utilization in combination with the usual spatial distribution of available light sources (high-power LEDs, laser diodes). A measure to further increase the system efficiency of the above arrangement according to claim 1 is to allow light incident on the tilt mirror pixels of the area light modulator in the OFF state to exit again unimaged from the complex of optical elements after reflection at the area light modulator without being allowed to enter the screen and to feed it again into the illumination light path by means of optical components in a second or further pass, so that it can pass through the illumination light path a further pass and, if possible, can enter the ON pixels during the further pass and be imaged in the direction of the screen.

Claims

1. A projection display comprising at least one light source (1), The projection display comprises at least one composite (2), said at least one complex (2) consisting of at least two optically distinct channels (K); said at least two optical individual channels (K) each being formed by a surface light modulator (D) which influences the light propagation direction pixel by pixel and by an optical element (O); and for every channel of said complex, characterised in that the entire collective channel of the optical elements of all the channels illuminates the area light modulator (D) upon light incidence on the complex (2), so that the optical elements (O) of the channels image the light reflected at the area light modulator (D) as an object structure, and all the imaging of the individual channels is superimposed on a screen (3) into one or more virtual or real overall images, Projection display.

2. The complex (2) is Optical individual channel K ｉ，ｊ It consists of: A two-dimensional i x j matrix, where o >= 3 and j lies in the xy plane. ｍａｘ ≧1, and their matrix elements (K ｉ，ｊ ) and the following formulas: [0010] and A surface light modulator (D) capable of pixel-by-pixel addressing of the light propagation direction by reflection or a combination of reflection and diffraction. ｉ，ｊ ) whose normal vectors of the light input vector and the light output vector extend parallel to the y-axis, and d rows, where d≧2 and j ｍａｘ A planar light modulator (D ｉ，ｊ ) and o and j ｍａｘ Optical elements (O ｉ，ｊ ) and Each optical individual channel (K ｉ，ｊ ) is configured as follows: upon light incidence on the complex (2), the individual channel (K ｉ，ｊ ) surface light modulator (D ｉ，ｊ ) is expressed by the following formula, with a counting scheme for i such that the (i+1)th channel row is always positioned between the ith channel row and the light source: [0025] or [0030] The optical element (O) is defined by the illumination allocation function b(i,j) according to ｉ，ｊ ) , As a result, the surface light modulator (D ｉ，ｊ After reflection at (D ｉ，ｊ ) is p( ｉ，ｊ ) = {O ｉ，ｊ }, the optical element (O ｉ，ｊ ) and all the individual projected images of said complex (2) are superimposed on a screen (3) into one or more virtual or real overall images, 2. The projection display of claim 1.

3. the illumination light paths (13) of all the individual channels are deflected at a reflector (19) arranged between the light source (1) and the composite (2); 3. A projection display according to claim 1 or 2.

4. the spatial separation of the illumination light path (13) and the projection light path (14) is achieved by total internal reflection in a prism (10) arranged between the light source (1) and the composite (2), whereby the illumination light path (13) is totally internally reflected and the projection light path (14) is transmitted in the direction of the screen (3), or the illumination light path (13) is transmitted in the direction of the composite (2) and the projection light path (14) is totally internally reflected in the direction of the screen (3), 3. A projection display according to claim 1 or 2.

5. Between the composite (2) and the screen (3) an overall lens with a variably settable focal length (5) is arranged, by means of which the optical axis of the individual image projection is arranged according to the set focal length, so that a variable image synthesis is dynamically realizable, for example an overall image with maximum illumination, minimum number of pixels and minimum pixel size or an overall image with minimum illumination, maximum number of pixels and maximum pixel size.

3. A projection display according to claim 1 or 2.

6. Within the complex (2), the projection channels (K ｉ，ｊ ) are assigned color filters having the same transmission spectrum, e.g., red, green or blue, and the corresponding planar light modulators (D ｉ，ｊ ) represents the corresponding color component as an ON pixel, and a full-color image has all channels (K ｉ，ｊ ) on the screen (3), 3. A projection display according to claim 1 or 2.

7. a subset of all projection channels are configured such that their corresponding projected overall images have a spatial offset in the plane of the screen relative to the projected overall images of a further subset of projection channels, said offset corresponding to a fraction of the pixel center-to-pixel spacing of the projected area light modulator pixels, and a superposition of all projections due to channel-independent modulation of pixel information of all area light modulators produces a cumulative overall image having a number of effectively displayable pixels that is greater than the number of displayable pixels of the individual projected images.

3. A projection display according to claim 1 or 2.

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