WO1999044091A1

WO1999044091A1 - Image reproduction unit

Info

Publication number: WO1999044091A1
Application number: PCT/DE1999/000592
Authority: WO
Inventors: Reinhard BÖRNER
Original assignee: HEINRICH-HERTZ-INSTITUT FüR NACHRICHTENTECHNIK BERLIN GMBH
Priority date: 1998-02-28
Filing date: 1999-02-26
Publication date: 1999-09-02
Also published as: DE19910157A1

Abstract

The invention relates to an image reproduction unit, comprising a screen, an image separating device arranged on the viewer side in front of the screen and parallel to same, and means for adjusting said image separating device. The image separating device is configured as a grid plate having imaging elements arranged in strips, which generates partial stereo images for the left and right eye of at least one viewer. According to the invention the means for adjusting the image separating device are configured as means for switching from auto-stereoscopic to monoscopic image display and vice versa. The screen (5, 28, 48) has an image field (5', 28', 48') and can receive at least one individual image in a monoscope position. In said position the screen (5, 28, 48) and the grid plate (6, 29, 52) can be positioned sufficiently close to the image separating device that the assigned representations of partial images on the eyes (11, 12, 19, 20, 22, 23, 32, 33, 43, 44, 46, 47, 55, 56) cancel each other out and that the individual image shown on the image field (5', 28', 48') of the screen (5, 28, 48) is sufficiently in focus for at least one viewer (10, 18, 21, 34, 42, 45, 57, 63, 64).

Description

description

Image display device

description

The invention relates to an image display device, comprising a screen and an image separating device arranged in front of the screen on the observer side, designed as a raster plate provided with strip-like imaging elements, which generates stereo partial images for the left and right eyes of at least one observer, and means for adjusting the image separating device .

Such an image display device is known from DE 196 08 305 A1. This image display device has a screen designed as a projection screen with a diffusely scattering diffuser plate and two screen plates provided with lenticular screens, of which the screen plate arranged on the observer side in front of the screen is an image separating device, the other screen plate is correspondingly arranged behind the screen. The image separating device and / or the grid plate arranged behind the screen is designed to be displaceable in the frontal direction relative to the screen and / or plane-parallel in the horizontal direction by means of an adjusting device. For stereoscopic reproduction of images, the diffusely scattering image surface of the diffuser plate can be acted upon by sub-projectors with sub-images of a stereo image recording, whereby the positioning of the raster plate arranged between the sub-image projectors and the diffuser plate can be applied to the diffuser plate with rows of the individual sub-images that are rastered into one another. The grid plate arranged between the diffuser plate and at least one observer can be positioned by means of adjustment so that the observer located in the region of the stereo zone can be represented by mapping the columns of the respective Sub images in one eye of the or each observer receives a stereoscopic image impression.

The lenticular grid of the grid plates are provided on the surface sides of the grid plates facing away from the diffuser plate, in order to avoid deterioration of the image reproduction caused by light sources in an observer space as far as possible. The grid plates are permanently at a distance of typically a few centimeters from the diffuser plate during stereoscopic reproduction.

With the generic image display device, stereoscopic image impressions can be produced for an observer, but it has the disadvantage that a stereoscopic image impression can only be generated for observers located with their eyes in assigned stereo zones. Outside the stereo zones defined by the imaging conditions, there is no satisfactory image impression for several, in particular moving, observers. This is also disadvantageous, for example, when several observers need a picture impression that is not necessarily stereoscopic, but at least clear, during meetings.

EP 0 694 179 B1 discloses a device for stereoscopic reproduction of images, in which the image separating device arranged on the viewer side in front of the screen has a raster plate designed as a lenticular grid plate. Cylindrical lenses of a lens arrangement of the lenticular screen plate are designed in accordance with a specific radiation-geometric relationship between the parameters of pitch width and thickness of the cylindrical lenses and the refractive index of the lenticular screen plate for a certain width of mono zones with a monoscopic image impression at a predetermined distance from the lenticular screen plate. As a result, observers staying in the monozones can perceive at least monoscopic image impressions in addition to the observer located in the stereo zone. In the case of the latter device, several observers have a clear image impression, but all users must be in certain zones in order to at least obtain the monoscopic image impression. Furthermore, the sufficiently precise design of the lenticular grid plate in accordance with the radiation-geometric relationship to be maintained is relatively complex in terms of production technology.

The invention is based on the object of specifying an image display device of the type mentioned at the outset, in which simple measures, particularly for several observers, make it possible to obtain a monoscopic image impression in front of the screen essentially independently of the position.

This object is achieved according to the invention in an image display device of the type mentioned at the outset in that the means for adjusting the image separation device are designed as means for switching from autostereoscopic to monoscopic image display and vice versa, that in a monoscopic position the screen can be loaded with at least one single image in that in the monoscopic position, the screen and the image separating device can be positioned approximately so far that the assigned image of partial images on the eyes is canceled and the single image that acts on the screen is recognizable for at least one observer with sufficient sharpness.

The fact that in the monoscopic position when the screen is loaded with a single image, for example one of the partial images of a stereo image recording, a graphic image or a text image that is independent of a stereo image recording, the raster plate and the screen are arranged so that the stereoscopic reproduction is canceled by a very simple approach and is replaced by a monoscopic representation of the or each individual image that is clearly recognizable for several observers at different positions in front of the screen, several can be carried out after an easily implemented switching measure At the same time, observers perceive sharp monoscopic image impressions, ie directional selectivity is eliminated in mono mode.

In one embodiment, the liquid crystal, plasma or electroluminescent based screen is designed as a flat screen. In another embodiment, the screen is designed as a projection screen with a diffusely scattering diffuser plate, for example made of glass, so that intermediate projection on the scattering plate, which represents the image area, takes place when partial images or individual images are projected on the back.

For particularly good monoscopic image impressions, it is expedient that in the monoscopic position a grid plate can be positioned directly adjacent to a screen carrying the or each individual image. If two raster plates arranged on both sides of a screen designed as a projection screen with a diffuser plate are provided, it is advantageous to further improve the image impression by positioning both raster plates directly adjacent to the diffuser plate in a monoscopic position.

In a group of exemplary embodiments, the or each raster plate is designed as a lenticular grid plate with a lens arrangement formed as imaging elements, for example by cylindrical lenses or rows of individual lenses. In this group of exemplary embodiments, particularly good monoscopic image impressions are achieved when the curved surfaces of the lens arrangement face the screen.

In a further group of exemplary embodiments, the or each raster plate is designed with a strip-like sequence of opaque shading areas with transmittive areas in between as imaging elements. With regard to good monoscopic image impressions, it is expedient in this group of exemplary embodiments that the shading areas face the image area. In a further development according to the invention, the device is designed such that, in the monoscopic position, the or each individual image is one of the partial images and applies full image information to the screen without being rasterized.

Further advantages and expedient embodiment of the invention are the subject of the subclaims and the following description of exemplary embodiments with reference to the figures of the drawing. Show it:

1 shows a schematic perspective illustration of an exemplary embodiment of the invention with a diffuser plate operated in rear projection as the image carrier and a raster plate of the image separating device,

2 shows a top view of the exemplary embodiment according to FIG. 1 with the diffuser plate and the grid plate of the image separation device in a stereoscopic position,

3 shows a top view of the exemplary embodiment according to FIG. 1 with the diffuser plate and the grid plate of the image separating device in a monoscopic position,

4 shows a schematic perspective illustration of a further exemplary embodiment of the invention with a diffuser plate operated in rear projection as the image carrier and two raster plates arranged on both sides of the diffuser plate,

5 is a top view of the embodiment of FIG. 5 with the diffuser plate and the grid plates in a stereoscopic position,

6 shows a top view of the exemplary embodiment according to FIG. 4 with the diffuser plate and the raster plates in a first monoscopic position,

7 is a plan view of the embodiment of FIG. 4 with the diffuser plate and the grid plates in a second monoscopic position, 6

8 shows a schematic plan view of a further exemplary embodiment of the invention with a flat screen as an image carrier and an upstream grid plate in a stereoscopic position and

Fig. 9 shows the embodiment of FIG. 8 with the flat panel support and the grid plate in a monoscopic position.

1 shows a schematic perspective illustration of an exemplary embodiment of the device according to the invention, which has a projector 1. The projector 1 is designed as a transmitted light projector on which a display 2 is placed. The display 2 is designed, for example, as a liquid crystal panel, to which partial images of stereo image recordings which are rasterized into one another in strips in columns can be fed in in a manner known per se.

The exemplary embodiment according to FIG. 1 has an objective 3 which can be moved axially and laterally with respect to the display 2, with which the interlaced partial images acting on the display 2 can be projected enlarged via a deflecting mirror 4 onto an image carrier designed as a diffuser plate 5. The diffuser plate 5 according to the exemplary embodiment shown in FIG. 1, with its image surface 5 ′ facing away from the projector 1, is made of glass in a diffusely scattering manner.

In the projection direction behind the diffuser plate 5, in the case of stereoscopic reproduction at a distance from the diffuser plate 5, a lens grid plate 6 is arranged as a grid plate of an image separating device, which has a strip-like lens arrangement 7 arranged parallel to the columns of the partial images. The lens 3 is displaceable both axially and laterally with respect to the lens grid plate 6 by means of an adjustment unit 9 controlled by a head detector 8, so that a first observer 10 located in the projection direction behind the lens grid plate 6 by means of the axial and lateral detection of the position of his head by means of of the head detector 8 with his left eye 11 and his right eye 12 within a movement space 13 indicated by crossed arrows via the directed projection of the partial images into one eye 11, 12 in each case receives a spatial image impression if the eyes 11, 12 are in assigned stereo zones.

The adjustment unit 9 is connected to a control unit 14, which further applies the display 2 in a stereoscopic position of the diffuser plate 5 and the lens grid plate 6 with the partial images rasterized in columns and in a monoscopic position explained in more detail below with at least one non-rasterized single image.

FIG. 2 shows a top view of the exemplary embodiment according to FIG. 1 with the diffuser plate 5 and the lenticular lens plate 6 of the image separating device in the stereoscopic position, in which the diffuser plate 5 and the lenticular lens plate 6 are spaced apart. In the illustration according to FIG. 2, pixels 15 of symbolically are shown on the diffuser plate 5 in parallel, generally columns of partial images, which can be imaged with an associated eye 11, 12 of the first observer 10 with cylindrical lenses 16 running at right angles to the plane of the drawing . The pixels 15 lie in the focal plane of the cylindrical lenses 16. The curved surfaces of the cylindrical lenses 16 preferably face the surface of the diffuser plate 5.

FIG. 3 shows a top view of the exemplary embodiment according to FIG. 1 with the diffuser plate 5 and the lenticular grid plate 6 of the image separating device in a monoscopic position in which the diffuser plate 5 and the lenticular grid plate 6 are arranged directly adjacent to one another. The curved surfaces of the cylindrical lenses 16 lie against the diffuser plate 5 while canceling the stereoscopic reproduction of the partial images, so that the lenticular plate 6 acts like a diffuse spreader. In the monoscopic position, the display 2 (not shown in FIG. 3) is fed by the control unit 14 with an unrastered partial image of a stereo image recording as a single image, which impinges full image information on the diffuser plate 5 over its area used in the monoscopic position. Undirected radiation, symbolically represented by a scattering cone 17, now emerges from the pixels 15 of the diffuser plate 5, so that, in addition to the first observer 10, for example a second observer 18 with his eyes 19, 20 and a third observer 21 with his eyes 22, 23 perceive an undisturbed drawing file. The monoscopic image impression is the same for all observers 10, 18, 21 regardless of their position in front of the diffuser plate 5.

4 shows a schematic perspective illustration of a further exemplary embodiment of the device according to the invention, the projection device of which has a first partial image projector 24 and a second partial image projector 25 which are arranged next to one another. With the partial image projectors 24, 25, two partial images of a stereo image recording can be projected onto the flat rear side of a first lenticular grid plate 26 as a grid plate. With the first lenticular grid plate 26, by means of a strip-like lens arrangement 27 opposite the flat rear side, the partial images originating from the partial image projectors 24, 25 can be imaged in a strip-like manner in a projection screen designed as a diffusely scattering diffuser plate 28 made of glass with a diffusely scattering image surface 28 '. On a side of the observer in the direction of projection behind the diffuser plate 28, a second lenticular grid plate 29 is provided as a grid plate of the image separating device with a stripe-like lens arrangement 30, with which the stripe-like partial images within a movement space 31 are directed to a left eye 32 and a right eye 33 of a first observer 34 can be mapped within the stereo zones assigned to the eyes 32, 33.

The first lenticular grid plate 26 can be designed to be movable. This is technically more complex, but improves the mono image. The second lenticular grid plate 29 can be displaced with respect to the diffuser plate 28 both axially and laterally by means of an adjustment unit 36 which can be controlled by a head detector 35 for the axial and lateral detection of the position of the head of the observer 34, in order for the observer 34 to move within the movement space 31 a stereoscopic reproduction of the Create drawing files. The adjustment unit 36 and the partial image projectors 24, 25 can also be acted upon by control signals from a control unit 37.

FIG. 5 shows a top view of the exemplary embodiment according to FIG. 4 with the diffuser plate 28 and the lenticular grid plates 26, 29 in a stereoscopic position. In the stereoscopic position, the lenticular lens plate 26 with the cylindrical lenses 38 forming the lens arrangement 27 is arranged at a distance from the diffuser plate 28 which corresponds to the focal length of the cylindrical lenses 38, the focal plane of the cylindrical lenses 38 on the diffusely scattering image surface 28 'facing the second lenticular lens plate 29. the diffuser plate 28 is located. As a result, on the surface of the diffuser plate 28 facing the second lenticular grid plate 29, the partial images, which are rasterized into one another, are produced from rows of image points 39.

The second lenticular grid plate 29, which is associated with the image separating device, is likewise arranged at a distance corresponding to the focal length from the diffuser plate 28 and forming the lens arrangement 30 and corresponding to the image surface 28 'occupied by the pixels 39 and corresponding to that with reference to FIGS FIG. 3 illustrates the exemplary embodiment for imaging the partial images that are rasterized into one another in one eye 32, 33 of the first observer 34.

Fig. 6 shows a top view of the technically simpler embodiment (a drive is required) according to Fig. 4 with the diffuser plate 28 and the lenticular plates 26, 29 in a first monoscopic position in which the second lenticular plate 29 with its cylindrical lenses 40 directly to the pixels 39 having the image surface 28 ′ of the diffuser plate 28. As a result, the second lenticular grid plate 29 acts as a diffuse scatterer, emitting undirected radiation within scattering cones 41 behind the cylindrical lenses 40, so that in addition to the first observer 34, for example, a second observer 42 with his eyes 43, 44 and a third observer 45 with his eyes 46 , 47 when a partial image projector 24, 25 is actuated to act upon the diffuser plate 28 with only a single individual image 10 perceive monoscopic image impressions regardless of their position in front of the diffuser plate 28 over the surface of the diffuser plate 28 used in the now monoscopic display while canceling the stereoscopic display.

FIG. 7 shows a top view of the exemplary embodiment according to FIG. 4 with the diffuser plate 28 and the lenticular grid plates 26, 29 in a second monoscopic position, in which the first lenticular grid plate 26 with its cylindrical lenses 38 is also arranged directly adjacent to the diffuser plate 28 (two drives required). The directional selection is also canceled in this position of the two lenticular grid plates 26, 29, so that an improved monoscopic image impression is realized for the observers 34, 42, 45.

8 shows a schematic plan view of a further exemplary embodiment of a device according to the invention with a flat screen 48 with an image area 48 ', which is formed by an image segment layer 51 which is arranged between a rear wall 49 and a cover plate 50 and is made of glass, for example made of liquid crystals. The image segment layer 51 is made up of individually controllable image segments, the image segments being combined in columns for stereoscopic reproduction and being controlled by interlaced partial images of stereo image recordings.

In the viewing direction in front of the flat screen 48, a raster plate 52 is provided as a raster plate of the image separating device, which is arranged in the stereoscopic position shown in FIG. 8 at a distance from the image segment layer 51 corresponding to the focal length of individual lenses 53 of a lens arrangement 54. In this exemplary embodiment, the individual lenses 53 forming imaging elements are arranged in the manner of columns in the direction of the partial images that are rasterized into one another. The lens arrangement 54 of the lenticular lens plate 52 is set up in such a way that a left eye 55 and a right eye 56 of a first observer 57 within a movement space 58 11 are each exposed to radiation from rows next to each other of a partial image in order to produce a stereoscopic image impression for the first observer 57. The distance and the relative position of the lenticular grid plate 52 to the image segment layer 51 can be adjusted by an adjustment unit 60 which is connected to a control unit 61.

FIG. 9 shows a top view of the exemplary embodiment according to FIG. 8 with the lenticular grid plate 52 and the flat screen 48 in a monoscopic position in which the individual lenses 53 of the lens arrangement 54 adjoin the cover plate 50 directly, caused by the control unit 61 and brought about via the adjustment unit 60 . As a result, the individual image segments of the image segment layer 51, the imaging effect of the lens arrangement 54 is canceled, so that the lenticular lens plate 52 acts as a diffusing screen and the radiation is non-directional from the individual image segments in scattering cones 62 that are independent of a stereo image recording, for example formed by a graphic image or a text image falls in the direction of the first observer 57 and further observers 63, 64, who perceive 48 monoscopic image impressions with their eyes 55, 56, 65, 66, 67, 68 regardless of their position in front of the flat screen.

Claims

12 Patent claims

1. Image display device, comprising a screen and an image separating device arranged parallel to the viewer side in front of the screen, designed as a raster plate provided with strip-like imaging elements, which generates stereo partial images for the left and right eyes of at least one observer, and means for adjusting the image separating device, characterized in that that the means for adjusting the image separation device are designed as means for switching from autostereoscopic to monoscopic image display and vice versa, that in a monoscopic position the screen (5, 28, 48) with image area (5 ', 28', 48 ') with at least one Single image can be acted on so that in the monoscopic position the screen (5, 28, 48) and the grid plate (6, 29, 52) of the image separating device can be positioned approximately so far that the associated image of partial images on the eyes (11, 12, 19, 20, 22, 23, 32, 33, 43, 44, 46, 47, 55, 56) canceled and the single image affecting the image surface (5 ', 28', 48 ') of the screen (5, 28, 48) for at least one observer (10, 18, 21, 34, 42, 45, 57, 63, 64) sufficient sharpness is recognizable.

2. Image display device according to claim 1, characterized in that the screen is designed as a flat screen (48).

3. Image display device according to claim 1, characterized in that the screen is designed as a projection screen with diffusely scattering diffuser plate (5, 28). 13

4. Image display device according to claim 3, characterized in that on the projector side a parallel to the diffuser plate (5, 28) and with respect to this in the frontal direction movable grid plate (26) is arranged.

5. Image display device according to one of claims 1 to 4, characterized in that in the monoscopic position a grid plate (6, 26, 29, 52) on the screen (5, 28, 48) can be positioned immediately adjacent.

6. Image display device according to claim 4, characterized in that the projector side and the viewer side with respect to the projection screen with diffusely scattering diffuser plate (28) are arranged two raster plates (26, 29) in a monoscopic position directly adjacent to the diffuser plate (28) can be positioned.

7. Image display device according to one of claims 1 to 6, characterized in that the or each grid plate is designed as a lenticular grid plate (6, 26, 29, 52) with a lens arrangement (7, 27, 30, 53).

8. Image display device according to claim 7, characterized in that the curved surfaces of the lens arrangement (7, 27, 30, 53) face the screen (5, 28, 48).

9. Image display device according to one of claims 1 to 6, characterized in that the or each grid plate has a strip-like sequence of opaque shading areas. 14

10. An image display device according to claim 9, characterized in that the shading areas face the screen.

11. Image display device according to one of claims 1 to 10, characterized in that in the monoscopic position is a single image of one of the partial images, which acts on the screen (5, 28, 48) without rasterization with full image information.