WO1992007292A1

WO1992007292A1 - 3d-spectacles

Info

Publication number: WO1992007292A1
Application number: PCT/SE1991/000681
Authority: WO
Inventors: Seppo Hosio; Gabriel Daniel Dorobantu
Original assignee: The Big Four Optics Ab
Priority date: 1990-10-10
Filing date: 1991-10-09
Publication date: 1992-04-30
Also published as: AU8740291A; SE9003232L; SE9003232D0; SE467324B

Abstract

The present invention is an optical device, e.g., in form of 3-D spectacles (10) by which may be obtained a three dimensional illusion having a sense of depth out of an ordinary two dimensional image as, e.g., the image of a television set, the image on a film screen, ordinary two dimensional photos, paintings or any other kind of two dimensional images. For each of the eyes is by an optical system (30v, 30h) via respective objectives (1v, 1h) created a secondary image onto a respective focussing screen made from a specific plastic material. These secondary images as viewed through the eyepieces of the systems will then by the human brain be perceived similar to ordinary stereoscopic images and thus create a stereoscopic illusion out of the originally two dimensional image. The distance between the eyepieces may be adjusted by an adjusting knob (8) and each of the optical systems (30v, 30h) are focussed by focussing knobs (7v, 7h).

Description

3D-spectacles

BACKGROUND OF THE INVENTION

The present invention relates to an optical device obtaining a stereoscopic picture illusion, more exactly applicable for 3-D spectacles in the viewing of, e.g. a television picture to obtain an illusory effect of depth in the two dimensional image.

A standard print, for example, on a paper contains two dimensions, width and height. A three dimensional image contains a further dimension, namely, the depth. A three dimensional illusion out of two dimensional images is normally obtained by using a double camera simultaneously exposing two pictures with a slightly different imaging geometry. The slightly different imaging geometry is achieved by placing the objectives of the double camera relative to the object such, that the distance between the objectives corresponds to the distance between the eyes of an observer. Images obtained in such a way will each correspond to the visual impression which an observer normally would obtain from each one of the eyes, resulting in that the total visual impression will be an experience of a three dimensional image when the prints are viewed in an apparatus where each eye only sees the respective print. This principle is easily feasible for still pictures and is for example to be found in form of a toy called "Viewmaster" in which a disc having a number of double prints is placed inside specially designed binoculars. The principle is technically possible for live pictures even if the system in that case will be fairly large scale. The principle works of course equally for black and white images and color images.

In connection with printing of images for a stereoscopic illusion, a color separation is made such that, for example, one image is printed using green color onto the other image which is printed in red color. To obtain the stereoscopic illusion spectacles having one red filter for one eye and a green filter for the other eye to separate the respective two dimensional images, whereby the eyes will receive a slightly different information which by the human brain will be interpreted as stereoscopic viewing and the image will obtain the third dimension of depth. This technique is used also for obtaining "live" images as in showing of motion pictures but is limited in that with this technique the resulting "three dimensional" image will be a picture having a mix of red and green, i. e. principally an image having a reddish/greenish gray scale.

SUMMARY OF THE INVENTION

The object of the present invention is to obtain an optical device by which a three dimensional illusion having the sense of depth will be obtained from a normal two dimensional image, such as, e. g., the image of a television set, the image on a film screen, ordinary two dimensional photos, paintings or any other kind of two dimensional image.

Another object of the present invention is to obtain a pair of spectacles to be used, e.g., in viewing two dimensional television or motion pictures to achieve a further impression of dimension in the observed image.

The invention comprises a separate optical system for each eye, and functions according to the following principle:

If an ordinary two dimensional image such as, e. g., a television image is viewed through the 3-D spectacles, the image will be experienced as three dimensional because each eye observes a two dimensional image recreated onto the respective focussing screen made of a specific material in each of the separate optical systems constituting the 3-D spectacles. The human brain mixes these two recreated two dimensional images which is each viewed by one eye and translates these both visual impressions to one sole picture which then gives rise to a three dimensional illusion having a sense of depth within the image.

This three dimensional illusion is obtained with the according to established technique otherwise constructed optical systems owing to the combination of a Fresnel lens and a dedicated focussing screen made of a specific plastic material having a very characteristic light transmission property resulting in that the images are not present in one but rather in a number of layers of the focussing screens.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is described by means of a preferred embodiment and by means of the attached drawings in which:

Fig. 1 is a principal sketch of the basic optical system used in the present invention,

Fig. 2 is a principal sketch of the optical system for one eye in a pair of 3-D spectacles,

Fig. 3 is a sectional view of a preferred embodiment of a pair of 3-D spectacles according to the present invention, and

Fig. 4 is a perspective view of a preferred embodiment of a pair of 3-D spectacles according to the present invention.

DETAILED DESCRIPTION

In Fig. 1 is illustrated a basic optical system, which by means of a focussing lens or an objective 1 may project an image onto a focussing screen 4. This onto the focussing screen 4 upside down projected image can be observed by means of a second focussing lens or an eyepiece 6.

Fig. 2 demonstrates a further evolved optical system 30 where a mirror 2 is used to direct the projected image towards the horizontally lying focussing screen 4 trough a Fresnel lens 3. Additionally there is between the focussing screen 4 and the eyepiece 6 a prism 5 to re-reverse the onto the focussing screen 4 projected image for a viewer such that it will be viewed in a correctly re-reversed position. Figures 3 and 4 demonstrates in a preferred embodiment how the optical systems 30v and 30h are built into a pair of spectacles 10 used to obtain a three dimensional visual experience of a two dimensional image from, e.g., a television set. The spectacles 10 additionally have a knob 7v and 7h, respectively, for each of the systems 30v and 30h to, according to known technique, mechanically (not shown) act on the focussing lenses lv and lh, respectively, to obtain focussing of the respective image which is projected by the focussing lenses lv and lh onto the respective focussing screen 4v and 4h. By means of the knobs 7v and 7h the distance between the focussing lenses lv and lh, respectively, and the focussing screens 4v and 4h may be adjusted. The spectacles further have an adjustment knob 8 which along with a not shown mechanical device is able to displace the two optical systems 30v and 30h sideways relative to each other to achieve that the optical axes of the systems 30v and 30h may align with the distance of pupils of a viewer.

The focussing screens 4v and 4h consist of a 1 mm or thicker (in the preferred embodiment 2 mm) semitransparent plastic material of, e.g., homopolymer polypropylene. Such a material is used among other things in the manufacturing of storage boxes for video cassettes by Petrofina SA, Denmark with the manufacturing code PPH 9089 S NATURAL. The focussing screens 4v and 4h together with the Fresnel lenses 3v and 3h in the optical systems 30v and 30h have the ability so that in each one of the systems is created an image which when viewed through respective eyepiece 6v, 6h will create an illusion of a third dimension which results in a depth within the image due to the functioning of the human brain to compile the two images seen by one pair of eyes into one stereoscopic image if the brain realizes that the two images present small geometric differences. Due to that the eyes at these focussing screens 4v and 4h do not perceive a plane image in only one layer but rather in a multitude of layers due to the characteristics of the material forming these focussing screens having a certain thickness and thus the image will not be created in only one well defined thin layer of a focussing screen, the brain will be fooled by the fact that it realizes small differences between the images of the two focussing screens, to in a normal way compile a three dimensional illusion of the originally two dimensional images in a similar way such as when viewing ordinary stereoscopically produced images, where a small real divergence is to be found between the images, which means that those by the aid of the human brain produces the stereoscopic visual impression. The best results using the 3-D spectacles according to the present invention are obtained from an original image illuminated from the back like, for example, a television image. If a television image which is showing, e.g., a landscape having a tree in the foreground, is observed using the spectacles 10, the observer will experience that the tree so to say will come out of the television screen and a very definite three dimensional experience of the television image is obtained.

In another embodiment of the present invention only one of the systems 30 used is having a focussing screen of the specific semitransparent plastic material as above, while the other focussing screen may be a much more transparent one to obtain even a brighter illusive three dimensional image impression especially in cases where the original image is fairly dark.

Claims

1. Optical device (10) for, from a two dimensional image (20), to a viewer creating a three dimensional visual impression out of a two dimensional image (20), the device including an optical system for each one of a pair of eyes comprising a primary focussing lens or an objective (1) and a secondary focussing lens or an eyepiece (6) aligned along an optical axis, characterized in that the objective (1) is arranged to project the two dimensional image onto a focussing screen (4) arranged between the focussing screen (1) and the eyepiece (6) as a secondary image to be observed though the eyepiece and that the focussing screen (4) constitutes a plastic material which is semitransparent.

2. Optical device according to claim 1 further comprising a mirror (2) and a prism (5), characterized in that a Fresnel lens (3) is arranged between the objective (1) and the eyepiece (6) along the optical axis of the device, preferably between the objective (1) and the focussing screen (4) and that the Fresnel lens is arranged perpendicular to the optical axis between the objective (1) and the eyepiece (6).

3. Optical device according to claim 2, characterized in that the prism (5) is arranged between the objective (1) and the eyepiece (6), preferably between the focussing screen (4) and the eyepiece (6), for correctly re-reversing the secondary image observed through the eyepiece (6).

4. Optical device according to claim 3, characterized in that the mirror (2) is arranged between the objective (1) and the eyepiece (6), preferably between the objective (1) and the Fresnel lens (3) to place the secondary image onto the focussing screen (4).

5. Optical device according to claim 4, characterized in that focussing means (7) is arranged within the optical system 30 to mechanically actuate the objective (1) for focussing of the secondary image onto the focussing screen (4).

6. Optical device according to claim 5, characterized in that parallel adjustment means (8) is mechanically connected to both optical systems (30a, 30b) to move these parallel in relation to each other such that their optical axes will be aligned with the distance between pupils of the viewer.

7. Optical device according to claim 6, characterized in that the plastic material of the focussing screen is constituted of a semitransparent disc of homopolymer polypropylen.

8. Optical device according to claim 7, characterized in that the eyepiece (6) comprises focussing means to for an observer focus the image projected onto the focussing screen (4) .