WO1990005319A1

WO1990005319A1 - Opto-mechanical device for three-dimensional viewing and image projection

Info

Publication number: WO1990005319A1
Application number: PCT/FR1989/000570
Authority: WO
Inventors: Gérard ROSSIGNOL; Yves Rossignol
Original assignee: Rossignol Gerard; Yves Rossignol
Priority date: 1988-11-04
Filing date: 1989-11-03
Publication date: 1990-05-17
Also published as: FR2638858A1; CA2002186A1; FR2638858B1; EP0407504A1; AU4522989A; JPH03503323A

Abstract

The present invention concerns a device for three-dimensional viewing and image projection. One of the main applications of this invention is the design of microscopes for viewing three-dimensional objects magnified to a high degree. A known projection lens (2) reflects on a double-sided mirror screen (5) the image of an object (1) illuminated through a slit diaphragm (3). Said mirror screen rotates around an axis (YY'), enabling the observer (8) to see the tridimensional image (6) in its inherent colour through a Fresnel-type lens-screen (7). A focussing correction lens (4) serves to correct the optical distortions created by the mirror and to collimate said image.

Description

Opto-mechanical device for projecting images and observing in three dimensions.

The present invention relates to an opto-mechanical device for projecting images and observing in three dimensions.

The technical sector of the invention is that of manufacturing projectors and relief images.

One of the applications of the invention is the production of microscopes allowing three-dimensional observation of objects under high magnifications.

We know indeed, different relief vision devices and for more than a century that man creates optical images, relief and color have been the object of his research in the world of the image.

In particular, it was in 1 ^ 7 _e Denis GABOR invented holography, but it was not until 1 ^Q 61 with the advent of the laser that it really emerged: shooting didn’t has nothing to do with photography and requires a photosensitive plate, lenses and mirrors and / or optical fibers, and a laser of coherent light following one or more wavelengths, providing on the one hand, a beam illuminating the object and refracted by it towards said photosensitive plate, and on the other hand, a reference beam illuminating the latter. Each point memorized on this plate then presents in fact an image of the object under a given angle, which allows the restitution under laser lighting, a three-dimensional vision from several angles and at high resolution.

However, the restitution is monochromatic, causes eye fatigue and requires a stable laser source. The adjustment of such systems is delicate and the equipment is expensive. The use of these is moreover limited to date in the fields of the Arts and has no significant industrial application, except in holographic interferometry in non-destructive testing of parts.

Furthermore when it is a question of observing objects, in particular those of small dimensions, the problems of the relief and the color arise in a predominant way and are difficult to solve in the apparatuses allowing the magnification of their images. It is in this particular application that other industrial relief vision equipment has been developed.

We can mention in particular the microscope from the company "VISION SAEMME", using a stereoscopic process without eyepiece, focusing in fact two images of the same object from two different angles, but the place of this focusing is by definition limited and does not allow seen from different angles. This system offers only a few parallaxes, a shallow depth of field, a limited viewing distance and reduced angular dispersion.

Relief microscopes are also known, such as that of the company "MICRO-CONTROLE" or "NACHET-VISION", which use a multi lenticular screen allowing a relief with low horizontal parallax but without vertical parallax and limitations in terms of magnification and of the viewing angle.

Other companies such as "NIKON", "OLYMPUS" or "ZEISS", have also made improvements to stereoscopy which with two flat images can only give an impression of relief, often with the use of binoculars.

Thus, current microscopes are more and more perfected and we have sought to act for better vision, sometimes on the nature of the light source, sometimes on the lighting system (fluorescence, black background), or even on the optics of the instrument with the development of a phase contrast microscope, the polarizing microscope and the ultraviolet light microscope. Finally, the marriage of the microscope and the computer can produce so-called three-dimensional images, but based on real images, in fact two-dimensional, and requiring a very elaborate and expensive processing system.

None of these systems gives a true image in relief, usable by several observers at the same time.

The problem posed is to make a three-dimensional image projection and observation device restoring an image retaining the natural colors of any object and observable from different angles of vision by several people simultaneously. A solution to the problem posed is a device for projecting images and three-dimensional observations of a subject diffusing light in natural colors, through a known projection objective, composed of at least one converging lens. , characterized in that it comprises an optical plane for reflecting light, such as a double plane mirror, or a transparent block containing a holographic optical element, rotating on itself at a speed of at least 20 turns / second around an axis of symmetry at best and intersecting the axis of said projection objective at any angle, so that said optical plane, or double mirror, or transparent block is always under the lighting of said objective and creates a volume fictitious inside which a three-dimensional image of said subject is visible and can be observed from several angles.

The result is a new opto-mechanical image projection and three-dimensional observation device.

The advantages of such a device are numerous and apply to different fields of use, including that of observation by microscopy or submicroscopy, but also for the reproduction of images in true relief projected for example in large rooms. audience or on appropriate individual and family screens or in training rooms by simulation through this real relief.

In the field of microscopy, the industrial fields are very numerous and demanding such as for the manipulation of electronic components or for the manipulation and the study of medical and biological phenomena.

Indeed, to date, the classic observation in microscopy or submicroscopy is done by binocular and / or on frosted screen as described above. In the first case, the magnified vision of the subjects observed can be stereoscopic with a depth of field, but without parallax or angular dispersion, allowing in fact only one observer at a time and an observation from a single given angle. In the second case, the image is in fact two-dimensional and without relief. As for the observation by holography, it is monochrome and distorts natural colors. In the present invention, great depths of field can be obtained by an optimum choice of the dimensions of the components of the device and their relative positions. In addition, the relief image produced has two vertical and horizontal parallaxes. The latter allows the observation of the magnified subject at different angles relative to the axis of the projection optics, which angles could in fact be from 0 to 360 °, except for the only inaccessible angles due to the fixings or the objective. projection. This image is observed from a few centimeters of the fictitious volume, up to several meters or tens of meters thereof, depending on the dimensions of the optics making up the device, allowing direct vision without the eyepiece by several people simultaneously and from different angles of vision. Another essential advantage is also that the three-dimensional image retains the natural colors of the subject observed.

The device according to the invention also allows an adjustment of the sharpness of the image by means of correction optics as described below. The assembly then constitutes a very efficient device which can be adapted to different uses. For use in microscopy, the corresponding instrument is more compact, because the subjects are small and therefore of a very reasonable cost of production with regard to the performances, unknown to date. The following description refers to the appended drawings, without any limiting character, describing an exemplary embodiment of an opto-mechanical device for projecting images and observing in three dimensions suitable for microscopic analysis of subjects of small dimensions, but other embodiments and other applications on a larger scale and with some modifications can be envisaged in the context of the present invention.

FIG. 1 represents a complete image projection device according to the invention, in side view.

Figure 2 shows a schematic perspective of the device.

Figures 3A and 3B are front and sectional views of an example of a double mirror. FIG. 1 represents a complete image projection device according to the invention, from a subject or object 1 lit by transmission from behind l or by reflection from any light source 13- The image of said object is then magnified through 5 of an objective 2 of any known type composed of at least one converging lens 2 and placed in the axis AA 'of the maximum illumination of the object 1, which axis is called the projection axis or of vision.

An optical light reflection plane such as a double plane mirror 5 chosen here in the present description and designating 10 below then itself or any other optical plane playing the same role, rotating around itself at best one of its axes of symmetry YY 'located in its plane, is placed in such a way that this axis intersects that of projection AA' at any angle a and at a distance such from the objective 2 as the projected image 6 by 15 it on one side of said mirror is as clear as possible.

The double mirror 5 is planar. It can be of any shape preferably, having an axis of symmetry, such as round or square; the material constituting it can be optical glass, high quality and scratch-resistant plastic, metal, graphite or any material

20 composite. It suffices that it is rigid enough to withstand the forces due to its rotation and light so as not to burden its inertia and its drive system. Its thickness must be as thin as possible, for example from one to two millimeters for a diameter of 12 to 15 centimeters. Its two sides are reflective, preferably

25 silvered or aluminized or gilded according to a mirror type quality.

This double mirror 5 can be replaced in another embodiment by a transparent block containing a holographic optical element called "EOH", which block in another embodiment can also have its reflecting faces like a mirror: this constitutes alternative embodiments of the optical reflection plane playing the same role as the double mirror.

The double mirror 5 rotates around its axis YY ′ thanks to any drive system 9 such as an electric motor powered by an electric block 10, connected to the sector 12 and controlled by an on-off switch 11.

The speed of rotation of said mirror or of any other optical plane playing the same role must be at least 20 revolutions / second (or 1000 revolutions / minute) and, preferably, greater than 50 revolutions / second (or 3000 revolutions / minute).

Indeed, all the images of real three-dimensional objects formed by large aperture optics are themselves in three dimensions (parallax and depth of field). Only the supports intended to receive these images allow or not to restore the relief.

A mirror such as that 5 in FIG. 1 can receive an image obtained 6 by focusing the different points of the subject observed on this mirror via an appropriate optic such as here 2, which is only visible under an angular opening corresponding to the diameter of the optics used.

The optics are therefore observed simultaneously in this mirror and the image in relief at the same mirror. If this mirror undergoes a rotation on itself at high speed, the projection optics disappears because of the scanning it performs in the virtual space of the mirror, and thanks to the retinal persistence of the observer 8 placed in the 'BB axis' of projection AA' reflected by said mirror, it only perceives the relief image of the object.

The speed of 50 rpm or 3000 rpm is the minimum speed to avoid an unpleasant beat during observation. The direction of rotation of the optical plane or the mirror has no influence on the image obtained. However, if this image is visible in relief by the observer 8, it is blurred and requires corrections if the latter wants to see it clearly. Indeed, the depth of field, which is small, requires the correction of the deformations of the opening of the optics 2 and the anamorphoses produced by the rotation of the mirror. The first correction. may consist in that said objective 2 comprises a diaphragm 3 rd form of slot, of length at least equal to the useful diameter of the largest converging optics of the objective, of width at best equal to one tenth of this diameter and whose median axis along its length is located in the plane defined by the axis of rotation YY 'of the optical plane or double mirror 5 and the axis AA' of said projection objective 2. This correction removes the blurring of image 6 and provides better depth of field.

The second correction may consist in that the projection system comprises a converging correction lens 4, of diameter preferably at least equal to the largest dimension of the optical plane or double mirror and placed between the latter and the projection objective. 2, at a distance from the aperture diaphragm 3 substantially equal to the focal length of this said correction lens 4, so that this distance is adjustable by any means to allow the image 6 to be collimated.

This second correction allows pseudo-collimation of the projection lens 2 with its diaphragm-slot 3 on the rotary mirror 5. which improves the brightness of the image 6, but above all, it removes anamorphoses due to the rotary mirror and to its position relative to the projection lens 2.

In a preferred embodiment, in order to simplify the production of the device in the case of an application such as microscopy, the angle αl of inclination of the axis AA ′ of said projection objective 2 relative to that of rotation YY ′ of said double mirror or optical plane is equal to approximately "", so that the optical axis of projection and vision is carried forward by approximately 90 ^e .

A third correction can constitute in that the device comprises a screen-lens 7 of the known Fresnel lens type with large aperture, situated between said double mirror or optical plane 5 rotating and the observer 8 and ensuring a magnification of the image 6 This final optic can ensure a magnification for example of double, of the rotating mirror 5 and of the image 6 and physically protect said mirror.

In addition, this lens screen 7 can be curved in the form of a portion of cylinder concentric with the shape of the fictitious volume created by the double mirror or rotating optical plane 5 ".

The combination of the corrective convergent optics k and the Fresnel lens type screen 7 gives a lenticular system having a focal length substantially equal to the distance from this optic 4 to the last lens 2_ of the projection objective 2.

The position of the different optics above can be such that the distances from the lens screen 7 to the double mirror or plane optic and from it to the converging corrective lens are equal to each other and substantially half the focal length of this so-called correcting lens 4, so that these distances are adjustable by any means to allow collimating to obtain the better image clarity 6.

All the optics used are made of conventional material. Only the lens screen 7 is of high quality plastic, for example of the scratch-resistant methacrylate type.

FIG. 2 is a simplified perspective view of the image projection device as described in FIG. 1. This figure represents in particular the optical phenomenon of diaphragm-slit collimation 3 in the vision zone. The double rotat mirror 5 is shown here immobilized. Only one part of the image 6 the object 1 is visible through the collimated image 15 diaphragm-slit 3 for a given observer.

Thanks to the corrective convergence system 4 and the standard Fresnel lens screen 7t the projection optics 2 and diaphragm-slit 3 are collimated in the viewing space 1'observer 8. The vertical angular dispersion β (direction of the ima collimatee 15) is of minimum 1 ^e , limited in fact by the own and relative dimensions of the different optics. This corresponds to vertical parallax of image 6.

When the double mirror or optical plane 5 is in rotation, collimated slot 15 scans horizontally, for a projection axis AA ′ preferably vertical, the space of vision of the observer 8 and thus analyzes the entire three-dimensional image and from different angles. Thanks to the retinal persistence, relief perception is visible under a horizontal angular dispersion 8, perpendicular here to the plane of Figure 2, p example of 60 minimum, in fact limited by the environment protection mechanism of the device because it could be Theoretical 36.

Figures 3A and 3b are front views and sectional example of a double mirror 5 described here as such and not pl as any optical plane playing the same role. To further improve the qualities of the relief image, the two faces of said double mirror can be engraved in the direction perpendicular to the axis of rotation YY ', in the form of a lined triangular network 17-

3B is a sectional view CC of said mirror and shows an example of type of etching chosen 17. The triangular grooves 16 are here dug about 0 ^e and a pitch of 100 to 200 microns for a mirror of diameter 12 cm ; this arrangement allows better vertical dispersion of the image when the projection optics have a small aperture. The result is then an improvement in the vertical angle β of observation defined in FIG. 2.

The networks 17 can also be holographic networks with steps of a few hundred nanometers depending on the wavelength of the laser source used to manufacture them.

The dual mirror 5 therefore produces two series of relief images p _er full turn and restores the relief and the natural colors of the object without need for eye or other external display elements. The image is brought into focus by displacement, by any means, of the projection optics 2 and 4 and / or by that of the subject 1. In the application to microscopy or submicroscopy, the device according to the he invention has dimensions and optical characteristics corresponding to this use, and can be integrated into a formwork giving it an appearance and presentation equivalent to those of known microscopes. The formwork and the covering of the apparatus may be made of metal or of high-resistance plastic, or of composite, or a combination of these materials.

It should be noted that one can film, photograph or holography sequentially using a pulsed laser or record video from the device. We can also subsequently project image 6 on a special screen while keeping the three dimensions.

The present invention is not limited to the embodiments described above and which constitute only exemplary embodiments to which variants and modifications can be made.

Claims

1. Device for projecting images and observations in three dimensions of a subject diffusing light in natural colors, through a known projection objective (2), composed of at least one converging lens, characterized in that it comprises an optical plane of reflection (5) of the light, rotating on itself at a speed of at least 20 revolutions / second around an axis of symmetry at best (YY ') and cutting the 'axis of said objective (AA') of projection at any angle (αl), so that said optical plane (5) is always under the light of said objective (2) and creates a fictitious volume inside which a three-dimensional image (6) of said subject is visible and can be observed from several angles.

2. A projection image and observation in three dimensions of claim ^'1, characterized in that said lens (2) for projecting includes a diaphragm (3) in slot-shaped length at least equal to the diameter useful of the largest converging optics of the objective, of width at best equal to one tenth of this diameter and whose median axis along its length is located in the plane defined by the axis of rotation (YY ') of the optical plane (5) and the axis (AA *) of said projection objective (2).

3. A three-dimensional image projection and observation device according to claim 2, characterized in that it comprises a converging lens (4) for correction placed between said optical plane (5) and the projection objective ( 2), at a distance from the slit-diaphragm (3) substantially equal to the focal length of this said correction lens (4), so that this distance is adjustable by any means to allow the image to be collimated (6 ).

4. Device for projecting images and observing in three dimensions according to any one of claims 1 to 3. characterized in that the angle (αl) of inclination of the axis (AA ') of said objective projection (2) relative to that of rotation (YY ') of said optical plane (5), is equal to approximately 45 ", in such a way that the optical axis of projection and vision is transferred by approximately 90".

5. Device for projecting images and observations in three dimensions according to any one of claims 1 to 4, characterized in that the speed of rotation of the optical plane (5) is at least equal to 0 revolutions / second (or 3000 revolutions / minute).

6. A projection image and observation in three dimensions according to any one of claims 1 to 5 _{»characterized} in that the optical plane of reflection (5) is a transparent block containing a holographic optical element.

7. Device for projecting images and observing in three dimensions according to any one of claims 1 to 5. characterized in that the optical reflection plane (5) is a double mirror, the two faces of which are silver, gold or aluminized according to a mirror type quality.

8. Device for projecting images and observing in three dimensions according to claim 7. characterized in that the two faces of said double mirror (5) are etched in the direction perpendicular to the axis of rotation (YY *) under triangular lined network shape (17) •

9. A three-dimensional image projection and observation device according to any one of claims 1 to 8, characterized in that it comprises a lens screen (7) of the known Fresnel lens type with large aperture, located between said rotating optical plane (5) and the observer (8) and ensuring an enlargement of the image (6).

10. A projection image and observation in three dimensions according to claim 9 characterized in _t that said lens-screen (7) is curved-shaped portion of cylinder concentric to the shape of the dummy volume created by the plan rotating optics (5).

11. Device for projecting images and observing in three dimensions according to claim 3 and any one of claims 9 and 10, characterized in that the distances from the screen-lens (7) to the optical plane ( 5) and from this to the converging correction lens (4), are equal to each other and substantially half of the focal length of this said correction lens (4), so that these distances are adjustable by any means to allow collimating and obtaining the best sharpness of the image.

12. Three-dimensional image projection and observation device according to claim 3 and any one of claims 4 to 11, characterized in that said converging corrective lens (4) has a diameter at least equal to the largest dimension of the optical plane (5) •

13. Device for projecting images and observing in three dimensions according to any one of claims 1 to 12, characterized in that it is of optical dimensions and characteristics such that it can be used in microscopic or submicroscopic observations and can be integrated into a formwork and a covering giving it a presentation equivalent to that of known microscopes.