WO2009098527A1

WO2009098527A1 - Binocular image-display device

Info

Publication number: WO2009098527A1
Application number: PCT/HU2009/000012
Authority: WO
Inventors: Làszló Holakovszky; Ádam SZENTGÁLI
Original assignee: Holakovszky Laszlo; Szentgali Adam
Priority date: 2008-02-05
Filing date: 2009-02-03
Publication date: 2009-08-13
Also published as: HU0800071D0; HUP0800071A2

Abstract

The essence of the binocular image-display system according to the invention is that a supporting frame head-mounted like spectacles and two image-display blocks containing microdisplays and image-magnifying optical elements connected to the supporting frame, the bridge (4) of the supporting frame (2) in front of the eyes (3a, 3b) is a transparent rigid plate which has two edge-surfaces consisting of parallel generating lines in front of both eyes (3 a, 3b), to which the two image-display blocks (9a, 9b) are attached via transparent slides (7a, 7b), like rails, in the bottom half of the field of vision on the outside of the bridge (4) with respect to the eyes (3a, 3b).

Description

Binocular image-display device

The subject of the invention relates to a binocular image-display device.

Head-mounted display devices (HMDs) are known of to a wide extent. A general characteristic of them is that they enlarge the images of small displays placed in the immediate vicinity of the eyes using optical elements, in this way the virtual image seen by the person wearing the HMD will be distant and have a wide visual angle. In theory HMDs may be used for the purpose of displaying any traditional electronic image, therefore, they may be connected to, among other things, video players, computers, televisions, game consoles, video cameras, GPS navigators, and with mobile telephones containing these. The optical element used to enlarge the image may be a lens, concave mirror or focussing prism, and a mirror, prism or semi-reflecting mirror may be used to refract the light path. The device used to electronically display the image may be, for example, a trans- illuminated LCD (liquid crystal display), a reflective LCOS (liquid crystal on silicon) or independent light-emitting ΘLED (organic light emitting diode) type microdisplay. The image displayed may be monocular (one image seen with one eye), biocular (one image seen with two eyes) or binocular (differing images seen by two eyes, if these depict the same thing then the image is monoscopic, if the same thing is depicted from two viewpoints then the image is stereoscopic).

Whilst wearing the devices fixed to the head as spectacles (like, for example, the devices according to figure 1 in patent descriptions nos. US D556,815 and US D513,031) they are fixed to the head with stems pressed to the two sides of the head and bent around the ears, and with a nose-bridge support. In general they contain a box in front of the eyes, which, apart from the two micro-displays that display the image and the optical system, contains the electronics that control the microdisplays, and as they are positioned in front of the eyes the cover vision at the height of the eyes, and partially cut the wearer off from the outside world. Oncoming vehicles, the faces of persons sitting/standing in front of the wearer are not visible for the wearer, the device makes the wearer somewhat "blind" and exposed. These features restrict the sphere of application, for example, while travelling on public transport - which otherwise would be a very important area of use, because travelling is "lost time" for the majority of people - it is not practical to use them.

In the interest of reducing their weight and creating a freer field of vision such HMDs were developed in which there is a display only in front of the one eye. However, while watching this image the other eye sees something entirely different in the same direction (the external environment), which is exceptionally disturbing. In order to avoid this the wearer is forced to shut one eye, which is tiring.

The devices according to patent specifications US 5,129, 716 and US 5,682,173 realise an image visible with both eyes and a freer field of view, in the cases of which the last mirror projecting the image into the eyes is fixed to the spectacle supporting frame with transparent fixing elements, in this way it is possible to see in all directions around the aforementioned element. However, the other elements of the image display system and its cover protrude into the field of vision and make unobstructed vision impossible.

The purpose of our invention is to overcome the listed faults and deficiencies, and to create a light device that provides a virtual image for both eyes with a wide angle of view, in the case of which apart from the virtual image displayed in the lower part of the field of view, the entire field of vision remains free.

In the interest of large angle of view of the image to be achieved with a simple optical system it is practical if the microdisplays are located near to the eyes, and in the interest of this, to use a binocular system, that is a separate image-display block per eye. hi a way known in itself the optical system inside these may be a loupe (a multiple lens system to reduce image-formation faults) or semi-reflective mirror and concave mirror combination, the screen may be a light-emitting or transmitting microdisplay, which to avoid a cable extension with too many cores should also contain a control circuit, therefore it should only need to receive the video signal and the power supply, and all these elements are surrounded by a housing containing a view window on the side the light ray is projected from.

The large exit pupil focussing element conforming to all IPDs - interpupillary distance - generally used in the known video glasses takes up a much greater angle of view that is necessary for a given wearer and as only a part of the focussing elements in front of the eyes serve to display the image, the rest unnecessarily covers vision. Besides a given amount of enlargement the aforementioned focussing elements have the smallest degree of field of vision cover if the aperture is precisely the same size as the cross-section of the light ray travelling towards to eyes from the display, and placed in front of the pupil the virtual image fills up the field of view taken up by the focussing element, hi order for the wearer to be able to see in every direction beside it, all of the other elements pf the image- display block must also be placed in the direction of the focussing element or covered by it, and in this case the thin housing that surrounds the focussing element, the microdisplay and the control circuit, appears as a blurred edged dark rim around the sharp and high- contrast virtual image and forms a part of the spectacle.

The basis of our invention is the recognition that a completely free field of view may be achieved around the image-display blocks described if they are fixed to the head with a supporting frame and adjustment elements that is transparent and that does not even cause light diffraction.

The essence of the invention is that the bridge of the supporting frame, that may be fitted to the head as spectacles, in front of the eyes is a transparent rigid plate which has two edge-surfaces consisting of parallel generating lines in front of both eyes, to which the two image-display blocks are attached via transparent slides, like rails, in the bottom half of the field of vision on the outside of the plate with respect to the eyes. hi a possible embodiment of the invention the bridge of the supporting frame is a thick planoparallel plate strip, which, from below and above, on the eyes side, is bordered by the edge surfaces cut out by the planes containing lines preferably crossing the eyeballs at their centre points. The significance of the edge surfaces is that they are seen on edge for the pupil of the eye turning towards it, therefore, they do not represent any obstruction to the field of view, and, also, they cannot reflect disturbing external light into the eyes. The bridge is surrounded on three sides by a slide consisting of transparent flat plate elements leaving the surface towards the eyes free, the lower part of which slide also contains a supporting plate protruding in the direction opposite to the eyeballs. The image-display block is fixed to the lower surface of this supporting plate, with a view window turning towards the eyeball, hi the central part of the bridge there is a nose bridge support formed in the simplest way as a surface cut-out in the average shape of the nose bridge. The two ends of the bridge continue in thinner and narrower, therefore with a small cross-section, flexible, transparent stems, which may be clipped onto the head of the wearer.

The figures used to present the invention in more detail show the following:

Figure 1: a possible embodiment of the binocular image-display device according to the invention while being worn, in side view,

Figure 2: the device according to figure 1 in perspective view,

Figure 3: a detail of the device according to figure 1 from the side, in cross-section, with the depiction of the eyeball and several pupil positions,

Figure 4: the device according to figure 1 in plan view, According to figure 1 there is a supporting frame 2 made of transparent plate, for example, optically clear polycarbonate, on the head 1 of the wearer, which consists of the planoparallel plate bridge 4 and flexible stems 6a, 6b that gently clamp onto the head 1 with a small cross-section leading behind the ears 5a, 5b and formed as a single member with the bridge 4. Slides 7a, 7b made of transparent plate are attached to the bridge 4, to which transparent supporting elements 8 a, 8b are fixed using optical adhesive, and to the obtuse angle lower parts of these the image-display blocks 9a, 9b are fixed, with view windows 15 a, 15b looking towards the eyes 3 a, 3b.

According to figure 2 the upper plates 10a, 10b of the slides 7a, 7b lie on the upper edge surface 11 of the bridge, the lower plates 12a, 12b onto the lower edge surface 13a, 13b not visible here, and the connecting plate 31a, 31b is connected to the side of the bridge 4 opposite to the eye side, and in the case of a suitably precise connection it may slide easily on it without being loose. In order to avoid scratching a distance gap of a thickness smaller than that of the central part of the connecting plates 31a, 31b can also be inserted. The relative large size of the slide ensures precise drive for moving the image- display blocks 9a, 9b, which is essential, because in this way the virtual images seen by the left and the right eye remain precisely in the correct position even while they are shifted about. It is essential to bond the supporting plate 8a, 8b on a large surface because of the stability of the image-display blocks 9a, 9b attached as a console. The range of movement of the image-display blocks 9a, 9b is determined by stops 14a', 14a", 14b', 14b" on the upper edge surface 11, which can obviously be created on the lower edge surfaces 13a, 13b too.

According to figure 3 the image-display block 9b contains a microdisplay 17b, a microdisplay control circuit 18b, a semi-reflecting mirror 19b and concave mirror 20b in a housing 21b surrounding them, on the front plate 22b of which in front of the eye 3b there is a view window 15b. In the case of precise adjustment with the help of the slide 7b, the light ray 24b starting at right angles from the centre point of the screen 23b of the microdisplay 17b and reflected by the optical elements travels through the pupil 25b looking in this direction and towards the centre point 27b of the eyeball 26b. It can be seen in the figure that if the plane of the upper edge surface 11 of the bridge 4 is appropriately diagonal, practically it goes through the centre point 27b of the eyeball 26b, then this surface is seen on edge by the pupil 28b of the eye 3b turning this way, therefore it cannot reflect external disturbing light onto the retina 29b. The end of the upper plate 10b of the slide 7b resting on this upper edge surface 11 situated at the eye 3b is only a narrow line, the image of which is completely obscured on the retina 29b because of its closeness to the eye 3b and because of the significantly larger diameter of the pupil 28b turning this way (anthropologically this diameter is about 4 mm on average). In the end, vertically the field of vision coverage is the following: the eye 3b has a free view above the upper plate 10b, it sees the upper plate 10b on edge, obscured, it sees without distortion through the transparent bridge 4, connecting plate 31b and supporting plate 8b resting on each other, the virtual image itself appears in the view window 15b, below the edge 22a, 22b there is free view, practically only the frame-like front plate results in a coverage, which appears as a dark frame with an obscured edge around the sharp, hard-contrast virtual image and forms a part of the spectacle.

According to figure 4 the bridge 4 and the stems 6a, 6b are constructed in one single piece, the upper edge surface 11 of the bridge 4 continues along the upper part of the narrower stems 6a, 6b, therefore it is seen by the eyes 3 a, 3b on edge, which means that in actual fact it is not visible. The gradation step 32b between the bridge 4 and the stems 6a, 6b falls in a plane, which crosses the centre points 27b of the eyeball 26b in a position that can be expected in the case of an average IPD, therefore it can be seen on edge by the eye 3b the pupil 33b of which is looking in that direction. It also stands for the other symmetrical side. From the microdisplay control circuits 18a, 18b not shown here an electric cable 34 leads to the source of the power voltage and the video signal, which may be for example an MP4 player, PDA, TV tuner, game console, video camera, GPS navigator, mobile telephone. If sound is also needed, it can be conducted to the ears 5a, 5b for example through a branch of the electric cable 34 not shown here.

From the aspect of operation, the binocular image-display system according to the invention us characterised by that its supporting frame 2 can be worn like spectacles, it is connected to the head 1 via a nose-bridge rest 35 resting on the bridge of the nose and stems 6a, 6b on two sides of the head 1, and bespectacled people may wear it above their own sight improving spectacles. The bridge 4 has a rigid construction to prevent it from becoming deformed even if the stems 6a, 6b are forced apart to an extent when such deformation may cause optical disturbance and result in the virtual images seen by the left eye and the right eye sliding away from each other.

In order to start use, first the device must be connected to the power voltage and video signal source, and the image-display blocks 9a and 9b must be placed exactly in front of the pupils. In order to do this, first the view windows 15a, 15b must be pushed in front of the eyes 3 a, 3b horizontally with the help of the slides 7a, 7b, and then, by lifting or lowering the ends of the stems 6a, 6b supporting against the side of the head 1, the centre of the virtual image must be adjusted vertically in the middle of the view window 15a, 15b. It may also be realised using a nose-bridge rest 35 with an adjustable height. The appearing image is a large, high-resolution, remote, bright, hard-contrast video image in a dark frame obscured by the edge of the front plate 22a, 22b surrounding the view window 15 a, 15b practically of a dark colour, with an entire view around it, with a clear field of vision. Although the virtual image and its narrow dark frame cover what is behind them, but as this cover appears on the lower-central part of the field of vision, it does not disturb the view at all, as the most comfortable way of viewing the image is at an angle suiting the ordinary reading angle while sitting at a desk; while walking it is projected to the ground, while driving it appears on the place of the dashboard and below it, whiling sitting on a bus or on an aeroplane it can be seen on the back of the seat in front.

The device with a free field of vision according to the invention can be used for example by students and young people: they can watch films, use the internet, watch television while travelling or waiting among people; by doctors, who, during laparoscopic operations can view the area operated on at an optimal angle, while they can also see the assistance and the instruments at the same time; by security guards, soldiers, policemen and fire-fighters, who can keep the image information needed for their measures and work tasks continuously in their field of vision; etc.

Apart from the construction examples described above, the head-mounted binocular image-display system according to the invention can also be realised in several other different ways within the scope of protection defined in the claims.

Claims

1. Head-mounted binocular image-display system which has a supporting frame head-mounted like spectacles and two image-display blocks containing microdisplays and image-magnifying optical elements connected to the supporting frame, characterized by that the bridge (4) of the supporting frame (2) in front of the eyes (3 a, 3b) is a transparent rigid plate which has two edge-surfaces consisting of parallel generating lines in front of both eyes (3 a, 3b), to which the two image-display blocks (9a, 9b) are attached via transparent slides (7a, 7b), like rails, in the bottom half of the field of vision on the outside of the bridge (4) with respect to the eyes (3a, 3b).

2. The device according to claim 1, characterized by that the bridge (4) is a thick planoparallel plate strip, which, from below and above, on the eyes (3 a, 3b) side, is bordered by the upper edge surface (11) and lower edge surface (13a, 13b) cut out by the plane containing two lines preferably crossing the eyeballs (26a, 26b) at their centre points (27a, 27b).

3. The device according to either claim 1 or 2, characterized by that the slide (7a, 7b) contains an upper plate (10a, 10b) lying on the upper edge surface (11), a lower plate (12a, 12b) lying on the lower edge surface (13a, 13b) and a transparent plate-connecting plate (31a, 31b) that rests at least partially on the surface of the bridge (4) on the opposite side to that of the eyes (3a, 3b).

4. The device according to any of claims 1-3, characterized by that a transparent supporting plate (8a, 8b) is bonded using an optical adhesive to the connecting plate (31a, 31b) of the slide (7a, 7b), to the lower part of which, which protrudes at an obtuse angle, the image-display blocks (9a, 9b) are attached, with windows (15a, 15b) that face toward the eyeballs (26a, 26b).

5. The device according to any of claims 1-4, characterised by that the range of movement of the image-display blocks (9a, 9b) is determined by stops (14a', 14a", 14b', 14b") on the upper edge surface (11) or lower edge surface (13a, 13b) of the bridge (4).

6. The device according to any of claims 1-5, characterized by that a surface element, a nose-bridge rest (35) is established on the middle, lower part of the bridge (4) that suits the shape of the bridge of the nose.