CA2399698A1

CA2399698A1 - Optical beam-splitter unit and binocular display device containing such a unit

Info

Publication number: CA2399698A1
Application number: CA002399698A
Authority: CA
Inventors: Laszlo Holakovszky; Endre Nagykalnai; Laszlo Kezi; Karoly Endrei
Original assignee: Individual
Current assignee: EMD Ltd (EYEGLASSES MOUNTED DISPLAY LIMITED); PRIMEX Ltd
Priority date: 2000-02-11
Filing date: 2000-11-22
Publication date: 2001-08-16
Also published as: MXPA02007705A; WO2001059507A1; KR20020086521A; BR0017118A; CN1452725A; EP1259850A1; AU1873801A; JP2003522974A

Abstract

The invention relates to an optical beam-splitter unit which contains crossed transparent planoparallel plates (6, 7), starting at a common intersection line (4) with light reflecting surfaces that diverge towards the light beam to be split. The binocular picture display device that is also subject of the invention contains an optical beam-splitter unit and it has first focusing elements (24) and mirrors in front of the eyes (25). This device is characterised by that its beam-splitter unit is the above described one, the first focusing elements (24) are placed at two opposite sides as seen from the direction of the beam arriving to the semitransparent reflective surfaces of the optical beam-splitter unit (22) i.e. from the receiving direction (5) and the common optical axis (23) of the first focusing elements (24) is at right angles to the receiving direction; outside the first focusing elements (24) on both sides a mirror is placed in front of each eye, and the semitransparent reflective surfaces of these mirrors enclose an angle .delta. 45~ .plusmn. 15~
with the above mentioned optical axis (23), and the intersection line of these reflective surfaces is parallel to the mirror crossing intersection line (4) of the semitransparent reflective surfaces.

Description

Nr~nted:l0-05-2002 DESC EP00981504.4 - PCTHU 00 0011 I PC'I'/H U 00/00119 Binocular display device The invention relates to a display device containing a beam-splitter unit. The utilisation of mirrors, prisms and semitransparent mirrors for splitting or uniting light beams has been known of for a long time. For example, the subject of USA
patent No. 4,924,853, (Jones et aL), is a device uniting two optical paths, containing two prisms one after the other and the reflective surfaces of these direct the beams coming from different directions onto the same optical path. Hungarian patent No. 186 558 also shows a device uniting two optical paths, where a mirror and a semitransparent reflective mirror, one after the other, direct the beams coming from different directions onto the same optical path. These solutions require quite a lot of space since they need two optical units for uniting the optical paths.
The international patent application No. WD 85/04961 shows a solution in which an X-cubic prism is used to split the optical paths, and the beam coming from one direction is directed onto two different optical paths by intersecting reflective surfaces. The mass of this device is relatively large, which is disadventageous in certain cases, for example, in the case of display units fitted on the head.
It is known that in many fields of life it is necessary to enlarge the angle of view of an object source for the viewer, and there are many different types of technical means for doing this, from simple loupes, through microscopes and laparoscopes to telescopes. In monocular devices the enlargement of the angle of view of the object source can only AMENDED SHEET

Printed:l0-05-2002 DESC EP00981504.4 - PCTHU 0~
~cTU~voo~oo ~ ~ 9 be seen with one eye. However, looking only with one eye is not natural, after a longer period it can even be disturbing, consequently it is essential to have devices which make it possible for both eyes to view the object source, therefore, a binocular device is needed, different forms of which are known and used.
A common feature of the known binocular devices is that they all contain a beam-splitter unit which splits the beam starting from the object source, such as a computer display fitted on the head, into two and directs it towards the left eye and the right eye. The beam splitting devices are the reflective surfaces of mirrors or prisms, which surfaces can be completely reflective or semitransparent.
Basically a beam can be split in two ways. In the first case the first sections of the two light paths from the object source to the left eye-ground and from the object source the right eye-ground form an angle, because they are travelling, for example, towards two non-transparent reflective surfaces placed next to each other in a V shape, reflecting the beams in different directions. In the second case the first sections of the light paths coincide, and then the sputter unit, which is a semitransparent surface, lets through a part of the beams and reflects the rest in a different direction.
A device representing the f"first case above, is the subject of Japanese patent description No. 06110013 {Tosaki et a1); of the Japanese patent description No. 07287185 {Akishi et al); and USA patent description No. 5,682,173 (Holakovszky et al). In these devices mirrors arranged in a V shape are used to split the Iight paths. A common disadvantage of these solutions is that as neither of the mirrors are placed opposite the screen, but one of them is placed slightly to the Ieft and the other one AMENDEi~ SHEET

Print~d:l0-05-2002 DESC EP00981504.4 - PCTHU 00 0011 3 PCT/1 iU0U1001 I 9 slightly to the right, trapezoid distortion occurs, end if the screen is placed too close to the meeting edges of the V-mirrors, then from certain points of the screen the beams do not even get to both mirrors. For this reason, quite a large distance should be kept between the screen and the V-mirrors, according to practical experience it should be twice the screen diagonal, which, on the one part, results in the increase of the constructional size of the device, and, on the other part, the distance between the screen and the lenses coming after the V-mirrors will be large, which reduces the feasible enlargement of the picture, because in the interest of comfortable viewing of the distant virtual picture the screen must be at a distance from the lenses equal to their focal length, and lenses with a greater focal length enlarge to a lesser degree.
In the case of binocular devices, for reasons of symmetry, the micro-display must be placed between the two eyes, and if there is a large distance between the micro-display and the V-mirrors, the device will be protruding like a beak, which, in the case of devices worn on the head, is unfavourable from an aesthetic point of view and because of the greater pressure exerted on the bridge of the nose. USA
patent No. 5,682,173 solves this problem by placing two more mirrors in the light path between the screen and the V-mirrors, and so the light path is reflected twice at an angle of 90°. In the case of patent specification No. 07287185 one single mirror is placed in the light path between the screen and the V-mirrors for the same purpose.
The second case of optical beam-splitting above, when the first sections of the light paths coincide, and then a splitter unit, which has a semitransparent surface, lets through a part of the beams and reflects the rest in a different direction, is AMENDED SHEET

Printed:l0-05-2002 DESC EP00981504.4 - PCTHU 00 PC'1'1HU00/OU 1 19 dealt with by the above mentioned patent application No. WO
85/04951 (Moss), which uses a well-known optical element, namely an X-cubic prism, the internal surfaces of which are semitransparent reflective surfaces, to split the beam coming from the object source. In this device the distance between the screen and the X-cubic prism can, in principle, be reduced to zero. However, the X-cubic prism is a solid body, and so it is heavy, the production and sticking together of the four right-angled prisms forming the X-cubic prism is expensive, complicated and labour intensive.
U.S. Pat. No. 5,739,955 (Marshall, WO 99/39237 (Ophey) and WO 98/ 10323 (Holmes) patent descriptions describe a beam-splitter unit containing two rectangular shaped semitransparent mirrors the side planes of which intersect each other in space, but the mirrors themselves do not intersect each other, because they are positioned shifted in space (below and above each other) and they touch each other only at one point as it is clearly shown in figure 2 of WO 99/39237 (Ophey), figure I of WO 98 J 10323 (Holmes) and figure 1 of U.S.
Pat. 5,739,955 (Marshall). Their position corresponds to the diagonal cross sections - of opposite directions, at an angle of 90° - of two cubes placed on top of each other so that their sides and four edges (e1, e2, e3 es e4) are each other's continuations, so that one of the mirrors corresponds to the diagonal cross section between the opposing a 1 and e3 edges of the lower cube, while the other mirror corresponds to the diagonal cross section between the opposing edges e2 and e4 of the upper cube. The disadvantage of the arrangement is that it makes the light paths from the light source to the left eye and from the light source to the right eye asymmetrical, and on the other part this arrangement obviously demands more space than the arrangement in which the two semitransparent mirrors form two intersecting diagonal cross sections of the AMENDED SHEET
4' CA 02399698 2002-08-07 ~6-0'S-t Printed:l0-05-2002 DESC EP00981504.4 - PCTHU 00 0011 same hypothetical cube (between edges a 1 and e3, and between edges e2 and e4). .
In U.S. Pat. No. 2,973,683 (Rowe) semitransparent, dichroic minors that cross each other are used to unite light beams. The advantage of the device is that the volume is minimal, because it uses semitransparent mirrors that are slipped into one another and that cross one another, so taking up a single place. Due to the thin plates - as opposed to the solid X-cubic prisms - the weight is also minimal. While, however, in the case of the precise grinding of the internal semitransparent surfaces - forming the diagonal planes of the cube - they meet at a single, extremely thin edge, in the case of the transparent plates with thickness v that cross each other, a crossover body is formed (a prism with cross-section v~v) which, in practice, behaves as an opaque body and causes a shadow line in an image projected through or looked at through the crossed plates. Such a shadow line passing through the middle of the picture is exceptionally disturbing and is completely impermissible in the case of a television or monitor picture.
The task of our invention is to provide an optical beam-splitter unit which overcomes the disadvantages of the other, presently known solutions designed for solving the same task and which has the smallest possible mass; which can be practically placed as close to the object source as desired, is capable of reflecting any point of the object source in two directions.
A further task of the invention is to provide binocular object enlarging devices made by the use of the above optical beam-splitter unit that are free of the imperfections of the other, presently known devices detailed earlier, and the mass and dimensions of which are small enough to be suitable to be used comfortably as a binocular screen-display fitted on the head.
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Printed:l0-05-2002 DESC EP00981504.4 - PCTHU OG t 6 PCTII I ~UU/UU 1 I 9 The beam-sputter unit of the binocular display device according to the invention is based on the recognition that two infinitely thin semitransparent mirrors crossing each other in an X-shape are theoretically suitable for the simultaneous solving of the above enumerated four tasks, because they perfectly split and direct in two directions the light beam arriving parallel with their bisector plane and at right angles to their intersection line, partly by transmitting and partly by reflecting it. In reality, however, there are no infinitely thin plates, and overly thin glass plates break, overly thin plastic plates bend, and if they are made thicker, the crossing zone of the mirrors creates an increasingly large shadow band. This crossing zone behaves in a certain - optical - sense as a non-transparent body and throws a strip shadow on the picture, and means increasing reflection fading. This shadow band is extremely disturbing for the person looking at the picture and in most cases - especially in the case of a video picture or computer screen - it is impermissible. Nevertheless, we recognised that if we construct an optical beam-splitter unit made of planoparallel plates at right angles to each other, which touch each other along one edge, and their end faces starting at this edge are optically flat, and their lateral faces starting at this edge towards the direction of the light beam to be split are semitransparent reflective surfaces, furthermore, if these planoparallel plates about one or two transparent bodies in a way that the end faces fall on the continuation of its, or their plane surfaces) that are either semitransparent reflective surfaces, or they consist of a semitransparent reflective surface and a completely reflective surface, the above mentioned shadow zone can be completely eliminated, and an optical beam-splitter unit can be made _ that satisfies all the four requirements of the task.
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sCA 02399698 2002-08-07 ~6-~rJ-i ~Printed:l 0-05-2002 DESC EP00981504.4 - PCTHU 00 001 7 PCT/I i U 00/00 I 19 The binocular display device according to our invention is based on the recognition that it can be constructed with minimal dimensions and mass if - the light beam starting at the screen of the microdisplay is split by two reflecting surfaces with dimensions corresponding to the screen, that cross each other in an X-shape, because these direct the beam to the left and to the right in the same volume;
- the optical beam-splitter unit with the smallest mass is that according to this patent application, because the light planoparallel plates have two continuous reflective surfaces;
- the largest degree of enlargement of the microdisplay screen and at the same time the most compact arrangement can be achieved by focusing units placed into the light path near to the two opposite sides of the optical beam-sputter unit;
- when not in use the size of the device can be further reduced by folding in the jointed mirrors;
- the device that can be miniaturised with the above measures can be so small, that it can be placed crossways in the housing of a portable telephone; and its weight can be so small, that a carrying device is not needed (for example, a helmet, a headband, or spectacle-frame or nose clip.) for mounting it to the head, but it can be fixed to the bridge of the nose with a clip.
- When the device that may be clipped to the bridge of the nose is not in use it is most favourable to wear it as a medallion on a retaining Ioop similar to a necklace, in this case the device is always "at hand", similarly to a wristwatch we will be always carrying it, and if necessary it can be put on in one movement;
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CA 02399698 2002-08-07 06-OS-200a Printed:10-05-2002 DESC EP00981504.4 - PCTHU 00 CA 02399698 2002-08-07 $ ~C~1~1H1100/00119 - By forming the retaining loop as an electric cable and fitting it with two earphones fitted on opposing sections a device providing pictures and sound may be created in the simplest way, because in such a case the mechanical supporting instrument of the earphones is the electric connection cable itself;
- From the point of view of weight, volume distribution and aesthetic reasons it is favourable to place the other electronic units necessary for the operation of the device as far as possible from the display unit, while being worn in a control unit at the nape of the neck;
- It is favourable to build into the display unit or the control unit either a microdisplay drive circuit, a radio frequency transceiver circuit, a digital ,television reception circuit, a microprocessor and current supply for the purpose of wireless connection with external sound, data arid video signals (e.g. by mobile telephone, portable computer, game console, DVD player, digital television transmitter);
- It is also practical to build a microphone into the housing of the display unit, because then the device may be used as an information technology device terminal or as an independent information technology device; according to our recognition in this way we get a personal communicator that may be worn continuously and which may reach the sensing organs on the head in the following way:
a. / one of the earphones is placed into an ear, and you talk into the microphone at your neck (mobile telephone function);
b./ both earphones are placed into the ears (the sound heard has better acoustic properties; stereo sound possibility), AMENDED SHEET
06-05=

'rinted:l0-05-2002 DESC EP00981504.4 - PCTHU 00 0011 9 PC'1'/NU00/001 !9 you talk into the microphone at your neck or one held in front of your mouth;
c. / the display unit is clipped onto the bridge of the nose (virtual monitor function);
d. / the display unit is clipped onto the bridge of the nose, one or both of the earphones are placed into the ears (video glasses function, with mono, more acoustic or stereo sound).
We note that as described later in detail the display unit rnay also be supplemented with a miniature video camera, which extends the functions further.
On the basis of the recognition described above in detail the set task was solved with a binocular display device containing an optical beam splitter unit with reflective surfaces intersecting each other at an angle of 90°, first focusing elements and mirrors in front of the eyes encompassing the above beam sputter unit, where - the optical beam splitter unit consists of two transparent planoparallel plates having semitransparent reflective surfaces, starting from a common intersection line and diverging towards the beam to be split, and at least one body of a transparent material connected to the planoparallel plates, - the above planoparallel plates have end plates starting from the above common intersection line, - the above end plates are plane and optically flat surfaces practically polished to be transparent, - the above end plates are perpendicular to the side plate belonging to them, - the body or bodies have semitransparent reflective surfaces falling in the plane of the above end plates forming their continuations starting from them.
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CA 02399698 2002-08-07 ~6'0'~J-2~0L

Printed:l0-05-2002 DESC EP00981504.4 - PCTHU 00 CA 02399698 2002-08-07 10 PC~1~/HU00/OOll9 An advantageous realisation of the optical beam-splitter unit according to the invention is characterised by that - it has further second and third planoparallel plates uthich lie in the continuation of the first and second planoparallel plates with light reflecting surfaces diverging towards the light beam to be split and which abut the first and second planoparallel plates as transparent bodies.
- all the planoparallel plates are made of the same material with equal thickness and refractive index and they are oblate parallelepiped shaped and they join each other along edges parallel to each other and they form, in the section at right angles to the joining edges, an X-shaped unit.
We note here that all the side faces of all the planoparallel plates are, naturally, optically flat. An optically flat surface is understood as a flat surface the surface roughness of which is less than o = 10 A. A semitransparent surface is to be understood as a surface that partly transmits and partly reflects natural or polarized light.
The above defined construction of the optical ~ beam-sputter unit contains a first, a second, a third and a fourth pianoparallel plate of thickness v and refractive index n, arranged in an X shape in a way that the two lateral faces of the first and the third planoparallei plate are each bordered by the same planes, and similarly the two lateral faces of the second and the fourth planoparallel plate are each bordered by the same planes, the first end face of the first planoparallel plate towards the third planoparallel plate is in the same plane as the lateral faces of the second and fourth planoparallel plate towards the first planoparallel plat, and it is an optically flat surface, the second end face of the second planoparallel plate towards the fourth planoparallel plate is in the same plane as AIr~IENDED SHEET
os-o5 a Printed:l0-05-2002 DESC EP00981504.4 - PCTHU 00 0011 I l PCT/HU00/OU I 19 the lateral faces of the third planoparallel plate towards the second planoparallel plate, and it is an optically flat surface.
The lateral face of the first planoparallel plate towards the second planoparallel plate, the lateral face of the second planoparallel plate towards the frst planoparallel plate, the lateral face of the third planoparallel plate towards the second planoparallel plate and the lateral face of the fourth planoparallel plate towards the first planoparallel plate are semitransparent reflective surfaces. The first end face makes the semitransparent reflective surfaces of the second planoparallel plate and the fourth planoparallel plate continuous reflective surfaces, and similarly the second end face makes the semitransparent reflective surfaces of the first planoparallel plate and the third planoparallel plate continuous reflective surfaces, because being optically flat surfaces they reflect the beams falling onto them under the limit angle of total internal reflection.
The direction which falls in the bisector plane of the planes of the semitransparent reflective surfaces of the first planoparallel plate and the second planoparallel plate and is at right angles to the intersection line of the above semitransparent reflective surfaces and points towards the intersection Iine is called the receiving direction, because the X-mirror optical beam-splitter unit described above splits the beam coming from this direction perfectly, and the rectangular area between the external parallel edges of the semitransparent reflective surfaces of the first planoparallel plate and the second planoparallel plate, with a plane at right angles to the receiving direction is called the receiving side, because the object source can be placed here or further away from here.
A subject of the invention is a binocular display device, which has an optical beam-splitter unit, and, furthermore, AMENDED SHEET

Printed:l0-05-2002 DESC EP00981504.4 - PCTHU 00 i CA 02399698 2002-08-07 ~~ PCTfHU00/OOlI9 contains focusing elements and minors in front of the eyes, and which is characterised by that its beam-splitter unit is an X-mirror optical beam-splitter unit according to the invention and that two focusing elements are positioned at two opposite sides of the optical beam splitter unit as seen from the direction of the light beam arriving to the semitransparent reflective surfaces of the optical beam-splitter unit - i.e. from the receiving direction - and the common optical axis of these focusing elements is at right angles to the receiving direction, and on both sides, mirrors in front of the eyes are positioned outside these focusing elements, and the reflective surfaces of these mirrors are at an angle S of 45~ ~ 15~ to the mentioned optical axis, and the intersection line of the planes of the reflective surfaces of these mirrors is parallel to the intersection line of the mirror-crossing intersection line of the semitransparent reflective surfaces of the optical beam-splitter.
It is favourable if the optical beam-splitter unit, the focusing elements and the mirrors in front of the eyes are encased with a cover which contains a light admitting opening in front of the mirrors in front ~of the eyes and at the receiving side of the optical beam-splitter unit. Furthermore, it is also advantageous if the optical beam-splitter unit and the focusing elements are fitted in a housing which has a light admitting opening for the focusing elements and which. is covered by a cover-plate, and the mirrors in front of the eyes are attached to a first slider and a second slider the stems of which protruding into the housing are toothed racks, which are parallel to each other, and in between them there is a cogwheel that connects them and can move them in opposite directions.
According to a further construction example, the device contains an object source that can be, for example, the screen of a microdisplay. In this case it is favourable if the plane of the AMENDED SHEE'~' 'rinted:l 0-05-2002 DESC EP00981504.4 - PCTHU 00 0011 v microdisplay unit's screen is parallel to the plane determined by the mirror-crossing intersection line and by the optical axis, and is placed at the receiving side of the optical beam-splitter unit, and it is also favourable if the device contains at least one light source lighting the screen of the microdisplay unit, such as an LED. It can be also practical if that it contains a light source illuminating through the microdisplay unit from behind, which is placed between the microdisplay unit and the device casing. According to a further construction example on the two sides of the optical beam-sputter unit, in the light path, there is a liquid crystal shutter at right angles to the axis of the focusing elements.
It can be favourable if the device contains two clip plates which for a single unit with the device casing.
Another realisation of the picture display device is characterised by that on the side of the device casing closer to the head of the user of the device there are two hook rails made as one with the device casing, and their generators are parallel to each other; favourably the device contains a clip adapter fitted in between the haok rails, which clip adapter practically consists of a bent plate following the curve of a dent in the device casing, and two clip plates and wing plates the span width of which is equal to the distance between the hook rails.
Another realisation of the picture display unit is characterised by that it contains at least one microdisplay drive circuit, and/or a radio frequency receiver-transmitter circuit, and/or a power source and/or a microprocessor.
According to a further favourable realisation above one end of the casing there is a CCD picture recording chip sensitive to the infrared range, and above its other end a front lens is placed in a way that the third optical axis of the front lens is at AMENDED SHEET

Printed:l0-05-2002 DESC EP00981504.4 - PCTHU 00 CA 02399698 2002-08-07 ~~ PCT/HUUU/001 Z9 right angles to the detecting surface of the CCD picture recording chip. Above the eye mirror in front of the right eye a reflecting element reflective in the infrared range, transparent i'n the visible light wavelength range is placed in the light path between the right eye and the detecting surface.
Advantageously, above the front lens, there is an infraLED, and its light is guided towards the reflecting element.
It can be also practical if on top of the device casing above the dent in the device casing created for the nose, there is a picture recording CCD chip with a detecting surface in a plane parallel to the plane determined by the optical axis of the focusing elements and the mirror-crossing intersection line, and in front of it, above the microdisplay unit there is a second front lens with an optical axis at right angles to the detecting surface.
In the following construction example we use a reflective microdisplay, which needs to be illuminated at right angles to the plane of the screen. In this instance it is favourable to form the X-mirror optical beam-splitter unit from extremely thin (0.1-0.2 mm thick) planoparallel plates, and to illuminate the screen through these. In the interest of the light of the light source illuminating the screen, or directly reflected by the X-mirrors not shining into the eyes, between the light source and the beam-splitter unit we place a polarising plate polarising in the one direction, and in the light path we place a polarising plate on both sides of the beam-sputter unit polarising in the other direction (at right angles to the previous one), so only light beams that have been reflected from the screen the polarity of which has been changed get through the latter two polarising plates.
AIVIENDED SHEET

?rinted:l0-05-2002 DESC EP00981504.4 - PCTHU 00 0011 ~
15 PC~f/1-f UOOl00 I 19 If the light reflecting surfaces of the X-mirror shaped beam-splitter unit are optical layers that partly reflect and partly transmit the polarised light, in such a case the number of optical surfaces or elements that cause a large degree of light intensity loss is reduced, and due to this as compared to the that of the previous example the intensity of the light reaching the eye is increased by many times, or we can attain the same light intensity with a much smaller capacity light source consuming much less power.
In a further construction example two ends of a flexible retaining loop are fixed to the opposite ends of the console containing the eye mirrors of the display unit containing the micro display, the optical beam-splitting unit, the focusing elements, the eye mirrors, the display housing and the bridge of the nose clip, in which loop there are electric cables, and to which there is an earphone fixed per branch mechanically and electrically. The length of the retaining loop is longer than the diameter of the wearer's head taken at nose Ievel. In the section of the retaining loop to most distant from the display unit there is a control unit containing the electronics for the microdisplay drive, a power supply, a microprocessor, a radio frequency transceiver circuit and a digital television receiving circuit, in which the one branch of the retaining loop is fixed permanently and the other branch is fixed so that is may be disconnected.
In the following we will describe the invention in detail using the appended figures, which contain favourable realisations of the optical beam-splitter unit; figures helping the understanding of their functioning; as well as examples of advantageous realisations of the binocular picture display unit.
The content of the figures is as follows:
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Printed:l0-05-2002 DESC EP00981504.4 - PCTHU OU i I6 CA 02399698 2002-08-07 ~'L~~~HLI00/00119 Figure l: the left reflection beam path of known intersecting semitransparent mirrors;
Figure 2: the right reflection beam path of known intersecting semitransparent mirrors;
Figure 3: a cross-section sketch of one example of the possible realisations of the optical beam-splitter unit of the binocular display device according to the invention;
Figure 4: show further examples of the realisation possibilities of the optical beam-splitter unit in exploded perspective;
Figure 5: sketch of the arrangement of one realisation of the bonocular display device;
Figure 6: the device as in figure 5, but in perspective;
Figure ?: sketch view of a further realisation of the binocular display device according to the invention from above;
Figure 8: the binocular display device according to figure 7, with fixed mirrors in front of the eyes, in a compact casing, viewed from the receiving direction, in perspective;
Figure 9: another example of the binocular display device with adjustable mirrors in front of the eyes, in exploded perspective;
Figure 10: the moving mechanism of the sliders of the device in figure 9 viewed from above;
Figure 11: the device in figure 9, assembled, in perspective;
Figure 12: the arrangement sketch of another realisation of the binocular display device in perspective;
Figure 13: the clip adapter used with the device shown in figure 12, in perspective;
Figure 14: shows a realisation of the display device with its eye mirrors folded in towards the focusing elements, fitted in a camcorder;
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~ s os-o ?rinted:l0-05-2002 DESC EP00981504.4 - PCTHU 00 0011 I 7 PCT/I I UUOl001 I 9 Figure 1 S: the device like in figure 14, also fitted in a camcorder, with its eye mirrors folded out;
Figure 16: a further realisation of the binocular display device according to the invention, fitted in a mobile telephone, with its eye mirrors folded out, in perspective, shown during use;
Figure 17: sketch of a realisation of the binocular display device containing an emissive microdisplay unit and LCD
shutters, viewed from above;
Figure 18: a realisation of the binocular display device according to the invention, with a microdisplay driving circuit, radio frequency receiver-transmitter circuit, a power source and a microprocessor; in front-view;
Figure 19: a realisation of the binocular display device with an eye movement detecting system, in perspective;
Figure 20: a vision aid and night vision binocular display device realised according to the invention in perspective;
Figure 21: shows a sketch from above of a realisation of the binocular display device according to the invention, containing a reflective microdisplay and the elements illuminating it from the front;
Figure 22: shows the binocular display device as in figure 21 in side view; .
Figure 23: shows the binocular display device that can be worn as a necklace while being worn, on the wearer's head and neck, in perspective.
In figures 1 and 2 the beam path of a known, traditional X-mirror beam splitter unit causing a shadow line can be seen, belonging to the prior art, namely the planoparallel plate 1 corresponds to the dichroic mirror 21 shown in figure 8 of U.S. Pat. No. 2,973,683 (Rowe) patent description, while the planoparallel plates 2 and 3 correspond to the dichroic mirror AMENDED SHEET
CA 02399698 2002-08-07 06-~'rJ-200G

Printed:l0-05-2002 DESC EP00981504.4 - PCTHU 00 CA 02399698 2002-08-07 ~ ~ PC.~r/HU00/!~O 1 1 22.
As it can be seen in figures 1 and 2, an X-mirror optical beam-splitter unit has been constructed from planoparallel plates l, 2, 3 with transparent and semitransparent surfaces as shown by the figures in a cross section perpendicular to the intersection line 4 of the minor crossing. The figures show only the crossing zone of these reflecting surfaces. The planoparallel plates 2, 3 with their uneven, rough, thin surfaces 2a, 3a produced during normal cutting processes abut the wide lateral faces of planoparailel plate 1 perpendicularly to these lateral faces. If realised this way, then a zone with a width t, as shown in the pictures 1 and 2, does not take part in the reflection of the light beam denoted by the number 5 and an arrow. For the sake of better lucidity figure 1 shows only light beams a-k going to the left, figure 2 those going to the right.
As it can be seen in figure 1 when beam a reaches the semitransparent reflective surface of plate 1, it is partly reflected back at right angles, with half intensity, and it partly goes inside plate 1 with half intensity. The beam reflected back at right angles reaches the semitransparent reflective surface of plate 2, and is partly reflected back towards the object source, not shown here, with quarter intensity, and after refraction it partly goes inside plate 2 with quarter intensity, and then after being refracted again it leaves to the left - considering the situation shown in the drawing - at right angles to the receiving direction S, i.e. to the receiving direction denoted by an arrow.
Beams b, c and d have the same beam path.
Beam a reaches the semitransparent reflective surface of plate 2 first, and it is partly reflected back at right angles towards plate 1 and from there towards the abject source, and after being refracted it partly goes inside plate 2, and disperses on tr'~.e uneven and rough, that is, not optically flat surface of AMENDED SKEET
18 06-05~

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19 PC1'/HU(~0/00119 the end face 2a of plate 2. Beams f and g have the same beam path. When beams h, i, i and k reach the semitransparent reflective surface of plate 2, they are partly reflected back with half intensity towards plate l and from there towards the object source, and partly after being refracted they go inside plate 2 with half intensity, and then after being refracted again they exit from there and reach the semitransparent reflective surface of plate 1, where they are partly reflected back with quarter intensity and exit, and partly after being refracted they go inside plate 1 with quarter intensity. As it can be well seen in figure i, beams g, f, a arriving in the range between beams d and h do not take part in the picture display on the left, which means a screening - a shadow zone - with width t in the picture.
The reference numbers and signs in figure 2 have been used according to their meaning in figure 1. Beams a-a and i-1 take part in the picture display on the right as described above with relation to figure 1, but beams f, g and h arriving in the range between beams a and i disperse on the uneven, rough, not optically flat surface of the end face 3a of plate 3, so in this case, too, a zone with a width t does not take part in the reflection.
Figure 3 shows a construction example of the optical beam-splitter unit according to the invention, which has a first planoparallel plate 6 and a second planoparallel plate 7, and it also has a transparent body 10 made also of a transparent material, and according to this construction example, the thickness of plates 6, 7 differs from each other. Plates 6, 7 join each other at their edges 9a, 9b, and their lateral faces 6a, 7a starting at these 9a, 9b edges and-facing each other and made to be semitransparent reflective surfaces are at an angle of a=90° to each other. (In figure 3 we show in cross-section AMENDED SHEET

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perpendicular to the joining edges 9a, 9b the crossing zone of the parts composing the optical beam-splitter unit.) The end faces 6b, 7b that start at the lateral faces 6a, 7a, and are perpendicular to these lateral faces - i.e. the angles J3 shown in figure 3 are right angles -, are optically flat, which means that they are ground completely smooth and polished until transparent. Surfaces 7a, 6b being in the same plane in consequence of the described and depicted geometrical conditions as well as the surfaces 10a, lOb of body 10 also being in a common plane and in the continuation of the 7a, 6b surfaces are semitransparent reflective surfaces. We note here, that body 10 must not fill the space between the end faces 6b, 7b, this can be empty, too, because, as we well see later, the surfaces of body 10 that abut end faces 6b, 7b - if body 10 is transparent - do not play any role.
According to figure 3 when the light beam arriving from the receiving direction 5 denoted by an arrow reaches the semitransparent reflective surface of planoparallel plate 6 it partly goes inside plate 6 and is reflected on its end face 8 and then exits at its opposite lateral face, is partly reflected back, and reaches the reflective surface of the other planoparallel plate 7 where it is partly reflected back (this is not shown in the figure) and then partly enters plate 7 and after another reflection exits at its opposite lateral face. Light beam a splits into beams a' and a", which are perpendicular to the receiving direction 5, and they exit in opposite directions towards left and right eyes, that's while take part in the picture display, and as a result of this the disturbing shadow line in the middle of the picture as mentioned in connection with figures 1 and 2, is eliminated.
Figure 4 shows a possible practical way of attaching the planoparallel plates 11-14 - made of a transparent material, AMENDED SHEET

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e.g. glass - of the optical beam-splitter unit 22, X-shaped as seen from above, according to the construction shown in figures 3 to each other. According to this the X-shaped unit fits into the X-shaped slots 18 engraved into the surfaces of bearing plates 17 and 19 with thickness v' > _v (only slot 18 made on the surface of bearing plate 17 is shown in the picture). Bearing plates 17 and I9 are parallel to each other, and the slots are engraved in their surfaces facing each other. The width of the slots is practically the same as the width v of plates 11-14, and their depth fits also the size of the plates fitting into them. The planes of bearing plates 17 and 19 are perpendicular to the planes of the planoparallel plates.
In the case of the above construction example the lower of the two square, from above, bearing plates 17, 19 serves as base plate, the upper as cover plate. Plates I 1- I4 can be stuck in the slots 18 - falling geometrically into the diagonals of the bearing plates - along the surfaces of their end faces perpendicular to their reflecting surfaces. In this construction plates 11-I4 join along edges 9 in a way that the four planoparallel plates touch each other along one edge each, and their end faces encase an empty quadratic prism shaped area 8, a penetration prism.
According to another construction not shown in the figure the square shaped planoparallel plates I I-14 made of a transparent material are injection moulded plastic plates, and on their edge surfaces at right angles to the intersection line of the reflective surfaces they have locking pins with an axis parallel to the above intersection line, and so they can be fitted into the holes on the receiving optical device.
There are many other ways of attaching the planoparallel plates of the optical beam-splitter unit.
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CA 02399698 2002-08-07 06-05-200a Printed:l0-05-2002 DESC EP00381504.4 - PCTHU 00 - ~~(... ~/1'1VVV/UUl 1y Figures 5 and 6 show the optical beam-splitter unit 22, c~~hich is X-shaped in top view, constructed from four transparent planoparallel plates as can be seen, for example, in figures 4, and denoted here by a single reference number. There are two first focusing elements 24 placed on both sides of the optical beam-sputter unit. The semitransparent reflective surfaces of unit 22 are marked with dotted line. The common optical axis 23 of the first focusing elements 24 crosses the mirror-crossing intersection line 4 of the planoparallel plates, and it falls into the bisector plane of the semitransparent reflective surfaces. The first focusing elements 24 are multi-element composite achromatic lens systems - in this particular case they have four elements, from the direction of their optical axis 23 they are rectangular, that is they are bordered by planes, and these planes coincide with the overall planes of the X-mirror optical beam-splitter unit 22 parallel to the optical axis 23 of the first focusing elements 24. Two mirrors in front of the eyes 25 are positioned on the two sides of the first focusing elements 24, and the reflective surfaces of the mirrors are at an angle of 45~ ~ 15~ to their optical axis 23. The intersection Iine of the planes of the reflective surfaces of these mirrors (not shown in the figures, it is outside the surface of the drawing) is parallel to the mirror-crossing intersection line 4. In figure 10 we marked the path of an incident beam a which is guided by the semitransparent surfaces of the X-mirror optical beam-splitter unit 22 (see also figure 3) to the left eye 26 and to the right eye 27 of the person using the device partly by transmission and partly by reflection. The lenses of the focusing element 24 forming a four-element achromatic lens system can be attached to each other by sticking them together. As we have already mentioned, the first focusing elements 24 are rectangular from the direction of their optical axis 23, that is they are bordered by planes, and these planes AMENDED SHEET

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rte. i inuuvuui i coincide with the two edges of the optical beam-splitter unit 22 that are the closest to the receiving side and also with its two edges that are most distant from the receiving side, and also with the lower and upper border surfaces that are perpendicular to the mirror crossing intersection line 4. The mirrors in front of the eyes 25 are plane glass mirrors with their faces towards the first focusing elements 24 being mercurated.
Their shape is a trapezoid to fit the shape of the light path, their two edges are parallel to the mirror-crossing intersection line 4, their other edges are convergent in the direction of the edge closer to the eye.
The binocular display device according to figures 5 and 6, due to its small space demand, small weight and compact construction, can be used favourably as a binocular display unit for instruments and optical devices based on enlarging, such as endoscopes, laparoscopes, microscopes and telescopes.
The elements of the device are attached to each other practically, either with their own frame or case, or with the frame or case of the above mentioned instruments and optical devices.
The binocular display device according to figures 7 and 8 also has an X-mirror optical beam-splitter unit 22 (figures 3 and 4) with two first focusing elements 24 on its both sides, and a further mirror in front of the eyes 25 on both sides similarly to the construction shown in figures 5 and 6. These binocular display devices are encased by a casing 28 which has light admitting openings 28a, 28b of a size corresponding to the size of the light path, located in front of the mirrors that are in front of the eyes 25 and on the side of the X-mirror optical beam-splitter unit 22 facing the receiving direction 5. In the light admitting opening 28a there is a focusing element 29. As can be seen in figure 8, the casing 28 encases the optical AMENDED SHEET
23 CA 02399698 2002-08-07 06-05-200a Printed:l0-05-2002 DESC EP00981504.4 - PCTHU 00 CA 02399698 2002-08-0~ ~4 PC_'-T/HU00/00 ( 19 elements of the device in a compact way; the position of the openings 28a and 28b can be seen well also in figure 8. The device shown in figures 7, 8 is a binocular loupe according to its characteristics, and looking in its light admitting openings 28a, 28b the user can see with both eyes the enlarged picture of the object source being at the focal length or closer in the receiving direction in the trajectory of the light. The object source that is exactly at the focal length seems to be infinitely distant, and reducing the distance the virtual distance of the virtual picture is also reduced and any desired virtual picture distance, for example, the usual half meter used for viewing objects in the hands, can be set. The centres of the mirrors in front of the eyes should be approximately equal to the distance between the pupils of the person using the device in order to avoid distortion and to be able to see the whole picture, and for this purpose one needs devices with different eye mirror distances, according to the changing distance of the human pupils that is in most of the cases between 55 and 70 mm. In practice it is enough to produce a binocular loupe with 3 mm increments, that is, with six different distances (with 55, 58, 6I, 64, 67 and 70 mm eye mirror centre distances, and the person using the device can use that best fits his or her size.
An advantage of this construction is that it does not contain any moving parts, it does not need to be adjusted, the disadvantage is that it has to be produced in six different sizes and the same device cannot be used by persons of different pupil distance.
The device according to figures 9-1 I is a binocular loupe where the X-mirror optical beam-splitter unit 22, as shown, for example, in figures 4, with pairs of first focusing elements 24 on its both sides is encased in a casing 30 which has light admitting openings at its two ends and in the middle of one of AMENDED SHEET

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25 PC'I~II-IU00/DO I J 9 its longer sides, and there are ledges 3I on its internal side walls made by wall-thinning, at the ends of the side walls there are threaded fixing holes 32. From the top the X-mirror optical beam-sputter unit 22 and the first focusing elements 24 are closed with an insert plate 33 supported on the ledges with its projections, and in the centre of the insert plate 33 there is a hole 34, and on its two opposing sides there are two pegs 35.
On the above projections there are flanges 36 which form a constraint path from the external side for the stem of the first slider 37 and the second slider 38 moving above the insert plate 33. On the internal sides of the first slider 37 and the second slider 38 facing each other the constraint path is created by a cogwheel 39 and the pegs 35 of the insert plate 33. When the cogwheel 39 turns, it engages into the tooth racks 40 made in the stems of the first slider 37 and the second slider 38, and it moves the first slider 37 in one direction and the second slider 38 in the opposite direction. The cogwheel 39 has one axle, and it is made in one piece with the grooved wheel 4 ~
the axle 42 of which fits into the hole 34 of the insert plate 33 downwards, and into the blind hole situated in the centre of the cover plate 43, not marked here, upwards. The cover plate 43 is of the same size as the housing 30, the four open-end holes 44 in its four corners have the same axes as the four holes 32 of the housing 30, and with the screws 45 the cover plate 43 can be fixed to the housing 30.
According to figure 10, when the grooved wheel 41 is turned in the first direction 46, the cogwheel 39 made in one piece with it moves the first slider 37 in the second direction 47 and the second slider 38 in the third direction 48. The movement is stopped by the projection at the end of the tooth racks 40 in the one direction, and by the stubs 34 at the tapered ends of the first slider 37 and the second slider 38 in the other direction.
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2b PC'I'lHU00/00119 According to figure 11 the cover plate 43 of the assembled device leaves the edge of the grooved wheel 41 free on certain sections, and if it is turned by the tip of a finger, the mirrors in front of the eyes 25 fitted on the first slider 37 and the second slider 38 move at the same time either towards the housing 30, or in the opposite direction.
Since in the construction according to the previous description the mirrors in front of the eyes are mounted onto sliders inside the casing, which makes the adjustment of the distance between the mirrors in front of the eyes possible according to the pupil distance, along the direction parallel to the optical axis of the focusing elements, so the same device can be used by everybody. The sliders are cogwheels with their axes parallel to each other, forced to a rectilinear motion by a constraint path, and connected to each other by a cogwheel with an axle fixed to the casing, and placed in between the cogged sides of the cogwheels to form a system, and by means of this by turning the adjusting grooved wheel on the same axle as the cogwheel the two sliders and with them the two eye mirrors move parallel to each other, but in opposite directions, facilitating the positioning of both mirrors in front of the eyes.
Since the semitransparent reflective surfaces of the optical beam-sputter unit reduce the light intensity to a quarter of tie original one, it is practical to illuminate the object source for compensating the reduction and to ensure better illumination, so it is favourable if the device contains a light source directed at the object source, for example, a white light emitting LED
and a small sized power source. The use of a binocular loupe is more advantageous than the use of a monocular one, because it better suits the human way of seeing using two eyes, you do not need to close one eye, or squint with it, so you can work comfortably with this binocular device when performing long or AMENDED SHEET
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'rinted:l0-05-2002 DESC EP00981504.4 - PCTHU 00 0011 27 PCTIHt100/00 I 19 often-repeated medical, cosmetic investigations and precision-mechanical work. A binocular loupe used especially for work purposes is best used fitted to the head of the person using it, with the help of a headband, spectacle frame or nose-bridge clip. It is advantageous if the binocular loupe is connected to the headband or spectacle frame with an articulated mechanism, so in breaks from using the device it can be pushed up over the forehead.
Vile shall describe in the following constructions containing an object source. This object source is located in front of the receiving side of the X-mirror optical beam-splitter unit according to the invention, in a plane at right angles to the receiving direction. The object source can be non-transparent, translucent or transparent, lit or lit through by the external environmental light, lit or lit through by a light source or luminous by itself. According to its concrete effective form it can be a microfilm frame, diapositive film frame, paper picture, drawing or printed text, electronic screen or other object source.
According to the construction example in figur es Z 2 and ~ 3 in front of the receiving side of the X-mirror optical beam-splitter unit 22 of the picture display device functioning as a virtual display, on its side facing the arrow 5 indicating the receiving direction there is a microdisplay unit 49 as an object source with a light emitting screen, 49a, and the unit 22 is enclosed from two sides by two focusing elements on each side, and outside the focusing elements there is one mirror in front of each eye, arranged as in the construction examples in figures and 6, 7 and 8, as well as in figures 9- I 1. The plane of the screen 49a is parallel to the mirror-crossing intersection line 4.
The screen 49a is supplied with the necessary voltage and electric signals through a cable 50, from a voltage and video-AMENDED SHEET

Printed:l0-05-2002 DESC EP00981504.4 - PCTHU 00 28 PCT/I-IU00/OUl !9 signal source not shown here. The X-mirror optical beam-splitter unit 22, the first focusing elements 24 and the microdisplay unit 49 are built in a device casing 51 which contains light admitting openings 51a, 51b between mirrors 25 and the pairs of first focusing elements 24, and on its side opposite the rnicrodisplay unit 49 between the planoparallel plates of unit 22 opposite to the microdisplay 49, there is a dent 52 using the space not falling in the light path, to suit the bridge of the nose. On the two sides of the dent 52 there are hook rails 53 the generator of which is parallel to the mirror-crossing intersection line 4 of the X-mirror optical beam-splitter unit 22, and due to these hook rails 53 the device can be put on a bearing plate, not shown here, with a width suiting the distance between the bays of the hook rails 53. For example, if the mentioned bearing plate is in the middle of a spectacle frame, the device can be pulled onto this, and if it fits exactly, the device can be moved up and down the bearing plate and it can be stopped anywhere, for example, exactly in front of the pupils.
The mirrors in front of the eyes 25 are each attached to a mirror holding unit 54, which are connected to the sliders 56 by the help of joints having axes parallel to the mirror-crossing intersection line 4 of unit 22, which joints are moved by the cogwheel-toothed rack mechanism that can be studied in detail in figures 9 and 10 and also explained above in details (not shown here), if the grooved wheel 57 is turned with the tip of a finger of the user of the binocular display device. The mirror-holding units 54 with the brackets stretching before the eyes, connected to joints 55 can be folded in together with the mirrors 25 on them towards the first focusing elements 24, thus significantly reducing the volume of the binocular display device. The real dimensions of the binocular display device with AMENDED SHEET

2$ Ofi=05-'rinted:l0-05-2002 DESC EP00981504.4 - PCTHU 00 0011 t 29 PCT'/I-I000/001 I 9 its mirrors folded in can be so small (e.g. 1.5x2.5x3.5 cm) that it can be placed after usage in the hollow made in the casing of any of the video signal sources (not shown here) for this purpose, or it can be connected to the connector made on the casing 51.
The clip adapter shown in figure 13, and marked as one unit with the reference number 58 consists of a bent plate 59 following the curve of the dent 52 in the device casing 5I
according to figure 12, clip plates 60 continuing this curve, and elastic wing plates 61 protruding on two sides towards the hook rails 53. The clip adapter 58 is attached to the device casing 51 so that the ends of the wing plates 61 are guided in between the hook rails 53. In the figure the position of the clip plates 60 with respect to the user's bridge of the nose is shown with a broken line, the clip adapter can be fixed by forcing open the elastic plates. The clip plates 60 in their position drawn by dotted lines fit tightly to the bridge of the nose from both sides due to their elasticity like a pince-nez. The clip plates 60 can also be made in one piece with the device casing 5I, in this case the clip adapter 58 and the stud 53 are not needed.
A light emitting object source can be built into the binocular display device according to figure 12 as a virtual display unit, in front of the receiving side of the X-mirror optical beam-splitter unit, such as an AMEL (active-matrix electroluminescent), OLED (organic light-emitting diode), FED
(field-emission display), AMOLEP (active-matrix organic light-emitting polymer), OEL (organic electroluminescent) or VFOS (vacuum-fluorescent-on-silicon) micro display unit, which is supplied with the voltage and the electric signals needed for its operation through a cable 50 - as mentioned before - from a video-signal source carried by the person using it (mobile telephone, communicator, palmtop AMENDED SHEET

Printed:l0-05-2002 DESC EP00981504.4 - PCTHU 00 3 U PCT/I-I UOOlUO 1 7 9 computer, DVD player, video-game, video-camera recorder, digital camera, etc.). The device according to the invention can also be built into the above video-signal sources, in this case the person using the device must Iift the video-signal source to his/her eyes and look into the eye mirrors of the binocular display device. The use of a combined solution can be advantageous when the binocular display unit can also be viewed fixed to the video signal source, and when taken out of it, can also be attached to the head, especially in the case of mobile telephones, video cameras and digital cameras. Such a construction is shown in figures 14 and 15, where the device according to the invention as shown in figures 5 and 6 is applied as a viewfinder, as a monitor, built in the end of a palmcorder 62 video-camera opposite to the objective 63, so that the optical axis 23 of the first focusing elements 24 (figure 15), not shown here, is at right angles to the second optical axis 64 of the objective 63. When not in operation, the binocular display device is placed in a hollow made inside the camera casing, with the mirrors in front of the eyes 25 folded in, and this hollow is closed by a cover 65. When the sliding button 66 is pulled back, the device in mechanical connection with it slides out of the hollow on a constraint path created by the camera casing, opening down the cover 65 in front of it, and the mirrors in front of the eyes 25 open out completely with the help of spring joints 55 (See figure 15). Instead of this mechanical driving mechanism another version can be constructed vThere the device is pushed out and pulled back by an electric motor at the push of a button.
Consequently the binocular display device according to the invention can be used as a viewfinder/monitor in video cameras and their versions that also contain a picture-recording device (camcorders).
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'rinted:l0-05-2002 DESC EP009~1504.4 - PCTHU 00 0011 31 PCT'/HUOUI00 i 19 Traditionally two types of viewfinder are used: one of them is a normal one eye monitor where the microdisplay screen built in the video-camera is to be viewed with one eye through a front lens, which is not natural, tiring and makes the other eye squint. In the other case on the casing of the video-camera there is a flat panel monitor which can be folded out, but it is small in order to suit the size of the portable video-camera, it can be as big as half of a palm at the maximum, and it cannot be seen very well, the details of the pictures can hardly be seen.
In the construction example of figures 14 and 15 the picture of the binocular display device can be viewed locally by opening out the mirrors in front of the eyes, or the device can also be taken out of the video-camera and fixed on the head. As modern palm-sized video-cameras (palmcorders) are thinner than the distance between the pupils, when such a video-camera is lifted up in between the two eyes it cannot be seen with both eyes at the same time, as you should go cross-eyed to do that, only the eye mirrors with their bearing piece folded out in front of the eyes are screening for both eyes. This results in an optical effect that in all directions around the non-transparent, bright, contrasted virtual picture seen in the mirrors in front of the eyes there is a clear view at least for one of the eyes, that is the video-camera practically disappears from the field of view. For those making a recording it is especially advantageous fihat while they are looking at the picture of the viewfinder with both eyes, they see the whole area around the picture, and nothing is screened from the view.
According to figure 15 the binocular display device according to the invention, as a viewfinder, is built in the end of a mobile telephone 67, in other words the device is the viewfinder of a mobile telephone. The virtual picture is AMENDED SHEET
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32 PCT/N UOUlUU 1 I 9 displayed after the mirrors in front of the eyes 25 have been opened completely mechanically or by a motor.
Since the mobile telephone's own small screen is suitable for displaying only little picture or text information, for example an Internet web-site or a whole E-mail page cannot be read at this size. For this reason it is advantageous to build the binocular display device according to the invention in the casing of the mobile telephone or connect it to the mobile telephone's battery charger connection end as an external adapter. According to figure I6 in the present construction the binocular display device is placed in the end of the mobile telephone with the mirror in front of the eyes folded in, and by folding out the mirrors in front of the eyes and lifting them up in front of the eyes it can be viewed locally, or it can be taken out of the casing of the mobile telephone and attached onto the head.
The construction of the binocular display device according to the invention shown in figure 17 contains an emissive type, for example, an OLED 49 microdisplay. This construction is similar to that shown in figure 12, so the reference numbers used there are also used in figure 17. In the light path between the X-mirror optical beam-splitter unit 22 and the first focusing elements 24 there are liquid crystal shutters 69 which become dark or transparent influenced by the voltage, with the picture frequency of the microdisplay unit 49, in alternating phases.
According to figure 18 between the X-mirror optical beam-splitter unit 22 or the pairs of first focusing elements 24 and the device casing 51 there is a microdisplay driving circuit 77, a radio frequency receiver-transmitter circuit 78, a power source 79 and a microprocessor 80. Using these arrangements the binocular display device can be as compact as possible, no AMENDED SHEET

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33 PC'T'/HUUO/001 19 wires are needed for connecting it to the control signal, video signal and power sources and the necessary computations, picture processing and other tasks can be solved locally.
The binocular display device equipped with a system detecting the movements of the eye according to the construction example in figure 19, corresponds basically to the device in figure 12, with the exception that here above one end of the casing 51 there is a CCD picture recording chip 81 sensitive in the infrared range, and above its other end a front lens 82 is placed in a way that the third optical axis 83 of the front lens 82 is at right angles to the detecting surface 84 of the CCD picture recording chip 81. Above the eye mirror 25 in front of the right eye 27 a reflecting element 85 reflective in the infrared range, light-admitting in the visible light wavelength range is placed, made in one unit with the mirror in front of the eye 25, in a size and at an angle so that it reflects the beams starting from the pupil 86, iris 87 and sclera 88 of the right eye 27 onto the detecting surface 84 through the front lens 82. In the interest of even lighting of the right eye 27, above the front lens 82 there is an infraLED 89 placed at an angle that the infrared beam starting from it is projected onto the reflecting element 85, and after it is reflected back from there, it is projected onto the right eye 27. The CCD picture recording chip 81, the front lens 82 and the infraLED 89 are encased with a casing, not shown here, which contains a light admitting opening at the front lens 82, and which is combined with the device casing 51.
The picture detected by the CCD chip 81 is analysed with the help of a picture processing program by a microprocessor built into the binocular display device or connected to it with a cable, and from the movement and position of the contour of the iris and/or the pupil it calculates the point on the screen of AMENDED SHEET
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34 PC'rIfIUUU/UU~ 19 the microdisplay unit where the eye Iooks, and displays a cursor there, and it also detects the momentary hiding of the contour of the iris and/or the pupil by the eyelid (blinking), and it clicks interpreting it as a command. In order to increase the contrast of the dark pupil and the lighter iris, or the iris and the white of the eye {sclera) independently from the external light conditions and the disturbing sparkling of the eyes, the iris and its immediate environment should be preferably lit with infrared light, because the users do not see it, they are not disturbed by it.
The construction example presented in figure 20 is a vision aid and night vision device and is basically the binocular display device according to figure 12, but here on top of the device casing 5I, above the dent 52 created for the nose, there is a CCD picture recording chip 90, above the microdisplay unit 49 there is a front lens 91 placed in a way that the optical axis 92 of the front lens 91 is at right angles to the detecting surface 93 of the CCD chip 90. The CCD picture recording chip 90 and the front lens 91 is encased with a cover, not shown here, which contains a light admitting opening at the front lens 91 and is combined with the device casing 51. The detecting surface of the picture recording CCD chip 90 falls in a plane parallel to the plane defined by the optical axis of the first focusing elements 24 and the mirror-crossing intersection line of the beam-splitter unit 22 (see intersection line 4 1I1 figure 12). The picture recorded by the CCD chip 90 appears on the screen 49a of the microdisplay 49 (not shown in figure 20) with a light intensity that - depending on the actual setting - is multiple of the original intensity, and in this case the utilisation of this device is advantageous for people with reduced vision capability, who cannot adequately orient themselves under weak illumination conditions, for example, in the evenings or in AMENDED SHEET

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35 PCT/I-IUDO/00 t 19 half light. If the CCD is sensitive in the near infrared range, displaying this infrared picture on the screen of the microdisplay makes the orientation possible of the person using the device even in total darkness provided that the area is irradiated by an infrared light source.
As can be seen in figures 21 and 22, the microdisplay 49 placed at the receiving side of the element 22 made of very thin semitransparent mirrors is a reflective type, the display screen 49a of which is illuminated from the front by the Fresnel lens 94 located on the other side (as seen from the display) of the element 22, the greater part of which or alI of it is located in the space between planoparallel plates 13 and 14 and this Fresnel lens 94 makes the light-beam of the LED 95 parallel and projects it to the screen 49a through the first polariser 96 and the semitransparent surfaces of element 22.
The light beam arrives from the screen 49a to the eye through the X-mirror element 22, the second polariser 97a or third polariser 97b, the first focusing element 24 and the eye mirror 25.
According to the construction example in figures 23 view of a binocular display device which contains eye mirrors 25a, a microdisplay 49b placed between the eye mirrors 25a, a beam-splitting unit 22a, focusing elements 24a, a display housing 56a, a microphone 108, a nose clip 60a and a flexible retaining loop 105 that is longer than the diameter of the head of the wearer at nose level it contains. The retaining loop 105 is formed in part of wholly as electric cable, contains two earphones 106, a control unit 107, and either the control unit 107 or the display housing 56a contains any of the following:
the microdisplay drive electronics, a radio frequency transceiver circuit, a digital television receiving circuit, a microprocessor and a power source.
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CA 02399698 2002-08-07 06-~5-2~0L

Printed:l0-05-2002 DESC EP00981504.4 - PCTHU 00 C

~>crinuooioo > > 9 An advantage of the optical beam-splitter unit according to the invention is that it has a minimal space demand and minimal mass, that it can be placed as close to the object source, as you like, and the picture of the device is of exceptional quality. The advantages of the binocular picture display device are similarly its small space demand and its small mass, that it is simple to manufacture and the very many application possibilities.
The invention is not restricted to the construction examples of the unit, or of the device cited here, but in the area of the protected solutions defined by the claims many different constructions of it can be realised. So, for example, in the interest of enlarging the image further focusing elements and semitransparent or completely transparent mirrors may be placed.
AMENDED SHEET

Claims

1. Binocular display device, which contains an optical beam splitter unit with reflective surfaces intersecting each other at an angle of 90°, first focusing elements and mirrors in front of the eyes encompassing the above beam splitter unit characterised by that - the optical beam splitter unit consists of two transparent planoparallel plates having semitransparent reflective surfaces, starting from a common intersection line and diverging towards the beam to be split, and at least one body of a transparent material connected to the planoparallel plates, - the above planoparallel plates have end plates starting from the above common intersection line, - the above end plates are plane and optically flat surfaces practically polished to be transparent, - the above end plates are perpendicular to the side plate belonging to them, - the body or bodies have semitransparent reflective surfaces falling in the plane of the above end plates forming their continuations starting from them.

2. Binocular display device as in claim 1 characterised by that the optical beam-splitter unit (22), the first focusing elements (24) and the mirrors in front of the eyes (25) are encased with a cover (28), which contains a light-admitting opening (28a, 28b) in front of the mirrors (25) that are in front of the eyes and at the receiving side of the optical beam-splitter unit (22).

3. Binocular display device as in claim 1 characterised by that the optical beam-sputter unit (22) and the first focusing CLMS

elements (24) are fitted in a housing (30), which has a light admitting opening at the first focusing elements (24), and which is covered by a cover-plate (43), and the mirrors in front of the eyes (25) are attached to a first slider (37) and a second slider (38) the stems of which protruding into the housing (30) are toothed racks (40) which are parallel to each other, and in between them there is a cogwheel (39) that connects them and can move them in opposite directions.

4. Binocular display device as in any of claims 1 to 3 characterised by that it contains an object source.

5. Binocular display device as in claim 4, characterised by that the object source is the screen (49a) of a microdisplay (49).

6. Binocular display device as in claim 5 characterised by that the plane of the microdisplay (49) screen {49a) is parallel to the plane determined by the mirror-crossing intersection line (4) and by the optical axis (23), and it is placed at the receiving side of the optical beam-splitter unit (22).

7. Binocular display device as in claim 6 characterised by that it contains at least one light source lighting the screen (49a) of the microdisplay (49), such as an (LED 95).

8. Binocular display device according to claims 6 characterised by that in front of the screen (49a) of microdisplay (49) there is a reflecting or focusing element (94) placed on the other side of the element (22 which collimats and projects the light-beam of the light source, favourably an LED
(95), onto the screen (49a).

CLMS

9. Binocular display device as in claim 6 characterised by that it contains a light source illuminating through the microdisplay unit (49) from behind, and it is placed between the microdisplay unit (49) and the device casing (51).

10. Binocular display device as in any of claims 6 to 9 characterised by that on the two sides of the optical beam-splitter unit (22), in the light path, there are liquid crystal shutters (69) at right angles to the axes of the first focusing elements (24).

11. Binocular display device as in any of claims 6 to 10 characterised by that it contains two clip plates (60) that are made in as one unit with the device casing (51).

12. Binocular display device as in any of claims 6 to 10 characterised by that on the side of the device casing (51) close to the head of the user of the device there are two hook rails (53) made in one piece with the device casing (51), and the generators of which are parallel to each other.

13. Binocular display device as in claim 12 characterised by that the device contains a clip adapter (58) fitted in between the hook rails (53).

14. Binocular display device as in claim 13, characterised by that the clip adapter (58) consists of a bent plate (59) following the curve of the dent (52) in the device casing (51), two clip plates (60) and wing plates (61) the span width of which is equal to the distance between the hook rails (53).

CLMS

15. Binocular display device as in any of claims 5 to 14 characterised by that it contains at least one microdisplay drive circuit (77), and/or radio frequency receiver-transmitter circuit (78), and/or a power source (79) and/or microprocessor (80).

16. Binocular display device as in any of claims 5 to 15 characterised by that above one end of the casing (51) there is a CCD picture recording chip (81) sensitive to the infrared range, and above its other end a front lens (82) is placed in a way that the third optical axis (83) of the front lens (82) is at right angles to the detecting surface (84) of the CCD picture recording chip (81). Above the eye mirror (25) in front of the right eye (27) a reflecting element (85) reflective in the infrared range, transparent in the visible light wavelength range is placed in the light path between the right eye (27) and the detecting surface (84).

17. Binocular display device as in claim 16 characterised by that above the front lens (82) there is an infraLED (89), and its light is guided towards the reflecting element (85).

18. Binocular display device as in any of claims 5 to 15 characterised by that above the dent (52) in the device casing (51) created for the nose, on top of the device casing (51) there is a picture recording CCD chip (90) with a detecting surface (93) in a plane parallel to the plane determined by the optical axis (23) of the first focusing elements (24) and the mirror-crossing intersection line (4), and in front of it, above the microdisplay unit (49) there is a second front lens (91) with a fourth optical axis (92) at right angles to the detecting surface (93).

19. Binocular display device as in any of claims 5 to 18 characterised by that it contains a flexible retaining loop (105) that is longer than the diameter of the head of the wearer at nose level.

20. Binocular display device according to claim 19 characterised by that the retaining loop (105) is formed in part of wholly as electric cable.

21. Binocular display device according to claim 20 characterised by that the retaining loop (105) contains two earphones (106).

22. Binocular display device according to claim 22 characterised by that the display housing (56a) contains a microphone (108).

23. Binocular display device according to any of claims 19-22 characterised by that the retaining loop (105) contains a control unit (107).

24. Binocular display device according to claim 23 characterised by that either the control unit (107) or the display housing (56a) contains any of the following: the microdisplay drive electronics, a radio frequency transceiver circuit, a digital television receiving circuit, a microprocessor and a power source.