The invention relates to arrangements for the three-dimensional display, especially to such that provide a spatial impression to one or several viewers without any aids such as filter goggles.
Many methods and arrangements for spatial display are known that are based on the spatial or temporal splitting of different views of a scene on some image display device. The said views are, as a rule, either images of layers of different depths in space, or images recorded from different angles. Among the said image display devices, LC displays, for example, are increasingly used. U.S. Pat. No. 5,936,774, for example, describes methods and an arrangement for the autostereoscopic display of between two and four perspective views on an LC display. EP 0 791 847, EP 0 783 825, and JP 8 194 190 also describe arrangements for autostereoscopic presentation based on LC displays. An advantageous arrangement of this kind is described in DE 100 03 326 C2. This arrangement uses at least one wavelength filter array, which establishes different propagation directions for light coming from different pixels. The said pixels render bits of partial image information from different views of a scene or object. Because of the given light propagation directions, the viewer's two eyes predominantly see two different selections (a first and second selection, respectively) of views, which gives the said viewer a three-dimensional impression.
It is the purpose of the present invention to develop arrangements of the kind indicated above in such a way that an improved image quality results.
According to the invention, the problem is solved by an arrangement for spatial display,
comprising an image display device with a great number of picture elements (pixels) αV arranged in a grid of columns i and rows j, on which bits of partial image information from different views Ak (k=1 . . . n, n ≦1) of a scene or object can be displayed,
and further comprising at least one filter array arranged in front of or behind the image display device (seen in viewing direction) and consisting of a great number of filter elements βpq arranged in a grid of rows q and columns p, and transmitting light of different wavelength ranges and/or with different transmittances λb, with each filter element βpq essentially having the size of a pixel αij, and with a great number of the filter elements λpq being essentially opaque and a great number of them being essentially transparent to visible light, so as to establish propagation directions for the light radiated by the pixels αij,
and in which bits of partial image information from the views Ak (k=1 . . . n) are assigned to pixels αij, of the position ij according to the equation
where
k is the consecutive number of the view Ak (k=1 . . . n) from which the bit of partial information to be rendered on a particular pixel αij originates,
n is the total number of views Ak (k=1 . . . n) employed,
n′ is a selectable integral number greater than zero,
cij is a selectable coefficient matrix for combining or mixing on the grid the various bits of partial information originating from the views Ak (k=1 . . . n), and
IntegerPart is a function for generating the greatest integral number that does not exceed the argument put in square brackets, and in which
the filter elements βpq, depending on their transmission wavelength range and/or transmittance λb, are arranged on the grid of rows q and columns p according to the following equation:
where
b is an integral number that, for a filter element βpq in the position p,q, defines one of the intended transmission wavelength ranges and/or transmittances λb, and that may adopt values between 1 and bmax,
nm is an integral number greater than zero that preferably corresponds to the integral number n′,
dpq is a selectable mask coefficient matrix for varying the generation of a mask image, and
IntegerPart is a function for generating the greatest integral number that does not exceed the argument put in square brackets, in which, according to the invention,
the pixels αij not of all rows j and columns i alternatingly present bits of partial image information from different views Ak in such a way that, from at least two monocular viewing positions, one of the viewer's eyes exclusively or almost exclusively sees partial image information from a single view Ak and that, from a great number of viewing positions, each of the viewer's eyes monocularly sees essentially bits of partial image information from different views Ak so that the viewer has a spatial view of the scene or object presented.
The (great number of) propagation directions established for the light radiated by the pixels αij intersect in a great number of points, each of which may coincide with a viewer's eye position.
The transmission wavelength ranges or transmittances λb to be selected may be, e.g., the wavelength range of red, green or blue light, or transmittances that are essentially opaque and transparent to visible light. Moreover, transmittances may be defined that are, to the greatest possible degree, independent of wavelength, for example, a transmittance of 75% for essentially all of the visible light.
A combination of transmission wavelength ranges and transmittances is possible as well, e.g., a transmittance of 50% to red light.
With particular preference, the arrangement according to the invention designed in such a way that dpq and cij are identical or selected so as to make b(p,q)=k(i,j) for all pairs (p=i,q=j); preferably, exactly one (or a few) of the 1 . . . bmax transmission wavelength ranges or transmittances λb intended is selected to be transparent to essentially the entire visible spectrum, whereas the remaining transmission wavelength ranges or transmittances λb are selected to be opaque to essentially the entire visible spectrum. This ensures that the image combination structure of the partial image information from different views Ak on the image display device closely resembles the structure on the filter array; strictly speaking, the arrangement pattern of those pixels αij on the image display device which render image information from exactly one particular view
Ak is provided in equivalent form on the filter array by means of the filter elements βpq that essentially transmit the entire visible spectrum.
Another preferable embodiment of the invention is characterized by the fact that—apart from marginal zones of the filter array—each of the filter elements βpq essentially transparent to visible light immediately borders on at least one other filter element , essentially transparent to visible light in at least one row [(q−1) and/or (q+1)], and/or in at least one column [(p−1) and/or (p+1)].
Both the pixels αij and the filter elements βpq have essentially polygonal, preferably rectangular outlines. Nevertheless it also possible that filter elements βpq have, at least in part, non-angular, say, rounded outline segments.
Furthermore, as a rule, at least some mutually adjacent filter elements βpq border on each other at one or several edges of the polygonal, preferable rectangular outline.
In most of the arrangements described so far it is inherent that, out of a number of monocular viewing positions in the viewing space in front of the arrangement, bits of partial image information from at least two views Ak are made visible to one of the viewer's eyes, with at least one fifth of all visible pixels αij being essentially completely visible to that eye. In that way, one of the viewer's eyes, from several first viewing positions, essentially sees partial image information from exactly one view Ak, whereas, from other (second) viewing positions, the said viewer's eye sees an image mixed from bits of partial image information of several views. This mixed image can be caused (1) from the shift of the respective eye from the first to the second viewing positions in the plane parallel to the plane of the pixels, and (2) from a change of the distance of the respective eye from the plane of the pixels.
Preferably, the arrangement has exactly one array of filter elements βpq, and the distance z between the said array and the grid of pixels αij, measured along the normal, is defined by the following equation:
Here, sp denotes the mean horizontal distance between two adjacent pixels αij. If the filter array is arranged (in the viewing or normal direction) in front of the grid of pixels αij, z is subtracted from da: if the filter array is arranged behind it, z is added to da. pd is the viewer's mean pupil distance, and da is a selectable viewing distance.
Alternatively, it is also possible to select other (optical) distances z between the array of filter elements βpq and the grid of pixels αij. For most displays (LCD, plasma or other displays), the typical, but not exclusive range for z is about 0.4 mm . . . 25 mm.
In yet another favorable embodiment, the geometric form of all filter elements βpq is equal, and the geometric form of all pixels αij is equal as well; compared to the geometric form of the pixels αij, that of the filter elements βpq is smaller or greater in the horizontal and/or vertical direction by a corrective factor f, which is preferably 0.95 <f<1.05.
Provided the filter array is arranged in front of the image display device (in viewing direction), the corrective factor f is selected, e.g., by the equation
in which z can be entered as a range as given above, or as a fixed value (e.g., z=2 mm).
For rendering a colored image, pixels αij adjacent in rows or/and in columns preferably radiate light of different wavelengths or wavelength ranges, for example, red, green or blue light. This includes the possibility, of course, that the image display device is of the RRGB type, but monochrome image display devices can be used as well.
Eligible image display devices are, e.g., plasma displays, LC displays, OLEDs, OELDs, laser-based systems and other types, preferably with fixed and defined pixel positions. Image display devices with full-color pixels, such as, e.g., projection displays, can also be used.
As a rule, the propagation directions for the light radiated by the pixels αij are established as wavelength-dependent propagation directions.
Below, the invention is described in detail with reference to the accompanying drawings, in which
For the sake of clarity, the drawings are not to scale, as a rule, and they show only parts of the respective total views.
Let us assume that all embodiment examples described here are provided with exactly one filter array, which is arranged at a distance z in front of the image display device as seen in the viewing direction. Let us further assume that the image display device in all embodiments is, for example, a 15″ TFT-LCD made by LG, and has a pixel pitch of 0.3 mm×0.3 mm (RGB triplet).
The pixels αij used on the image display device are the RGB subpixels, so that a pixel αij has, for example, the dimensions of 0.1 mm (width)×0.3 mm (height).
Each filter element βpq is essentially of the same size as a pixel αij. The exact dimensions are calculated, for example, by means of the equations given herein before. Given the parameters pd=65 mm, da=700 mm and sp=0.1 mm, the resulting optical distance between the image display device and the filter array z=1.0786 mm, and the resulting corrective factor f=0.9984592. Hence, each filter element is 0.1 mm * f=0.09984592 mm wide and 0.3 mm * f=0.2995377 mm high.
There also exist a great number of viewing positions from which essentially bits of partial image information from several different views Ak are simultaneously visible to both of the viewer's eyes, each monocularly seeing predominantly bits of partial image information from different views, so that the scene or object shown also appear to be spatial to the viewer. A possible combination of bits of partial image information from different views (here, views A3 and A4) visible to one of the viewer's eyes is shown in
In the embodiment example with 4 views (n=4) described so far, bits of partial image information from at least two views Ak are inherently made visible to one of the viewer's eyes from a number of monocular viewing positions in the space in front of the arrangement according to the invention, with at least one fifth of the visible pixels αij being essentially completely visible to the respective eye of the viewer (see
A second embodiment example based on n=6 views is shown in
For the series of drawings
A filter array can be manufactured, for example, as a sheet of exposed and developed photographic film laminated onto a carrier substrate (e.g., of glass). Other manufacturing methods are also feasible, of course.
Additionally, arrangements according to the invention can be provided with a component for optional switching between a 2D mode and a 3D mode. This is possible especially if the filter array is provided (in viewing direction) behind the (translucent) image display device such as, e.g., an LC display. Behind the filter array there is a light source, and between the LC display and the filter array there is an electrically switchable diffusion disk that can be switched to be transparent in the 3D mode, and diffusing in the 2D mode. The diffusion cancels the light propagation directions established, so that, in the 2D mode, a largely homogeneous illumination of the LC display is achieved. Other versions for switching between 2D and 3D modes can also be implemented in arrangements according to the invention.
In special application cases, it may be advantageous to use several filter arrays.
The invention offers the advantage of providing an improved 3D image quality, since, especially from many viewing positions, it ensures good channel separation between the various views seen by the viewer's eyes.
Number | Date | Country | Kind |
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103 20 530.6 | Apr 2003 | DE | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/EP04/04464 | 4/28/2004 | WO | 10/28/2005 |