GB2128362A - Antiglare glasses - Google Patents

Abstract

Antiglare glasses comprising a pair of lenses (1) mounted in a lens frame (7). Each face of the lenses is formed by a plurality of liquid crystal cells (2). A control unit (3) provides for the separate control of each individual liquid crystal cell in accordance with electrical control signals derived from a plurality of light sensitive members (4) positioned on forward facing surfaces of the frame, whereby the transmissivity of the individual cells is selectively reduced in accordance with the light received by the light sensitive members. <IMAGE>

Description

SPECIFICATION Antiglare glasses The invention relates to antiglare glasses for protecting a wearer's eyes against glare effects of, in particular, moving light sources, such as car headlights.

Glare effects are a serious problem particularly in traffic. Various methods and devices have been suggested to eliminate their effects upon a wearer's eyes.

The most useful embodiments presently known are the goggles, examples of which are dislosed in patent specifications Nos. Ch 481645, DT 2626264, DT2514439, DT2443624, DT 2316849 and DT 2338400.

The methods suggested in these prior specifications only eliminate glare effects from point light sources, and reduce such effects when their direction of incidence is known.

This is achieved by obscuring definite ranges of the field of view by portions of the lenses. These lens portions are predetermined and are of a reduced light transmissivity. The ranges to be obscured are achieved by a movement of the head of the wearer between the eyes and the light source (Ch 481645) and are so arranged that the position of the obscured field of view can slightly be corrected by the movement of the head (DT 2316849). Such ranges can be different as concerns shape, arrangement and material.

It is known, for example, to use transparent coloured materials (Ch 481645, DT 2626764), of coloured transparent foils (DT 2443624), glasses embodied as grey filters incorporated in stripes of reduced light transmissivity and partially tiltable polarisation filters (DT 2338400).

In any event a partial obscuration is involved of a defined portion of the range of view of the eyes.

It is a feature of all previously suggested solutions that, apart from the glaring light source, further ranges are obscured and therefrom sections of additionally poor visibility result. It is a common disadvantage of the aforesaid antiglare devices that when the glare effect comes from an unexpected or extreme direction, the obscured ranges are not sufficient enough and cannot be achieved by movement of the head between the light source and the eye, respectively.

A readjustment by hand is only feasible solution under certain conditions.

It is an object of the present invention to obviate the above disadvantages of the known solutions.

It is a further object of the invention to provide antiglare glasses which automatically reduce an incident glare radiation which may be incident at different and varying angles.

According to the present invention, there is provided antiglare glasses comprising a pair of lenses mounted in a lens frame, the faces of each of the lenses being constituted by a plurality of liquid crystal cells, control units provided for separate control of each individual liquid crystal of said plurality of liquid crystal cells, and a plurality of light sensitive members electrically connected to the control units and positioned such that, together, they are associated with the whole range of vision of the eyes of a wearer of the glasses, with each light sensitive member being associated with a definite subrange of the angle of vision of the eyes.

Advantageously, the liquid crystal cells are attached to optically corrected lenses. The shape and dimensions of the liquid crystal may be selected as required. Each of the liquid crystal cells which covers a subrange of the angle of vision of the eyes is associated with a light sensitive member and electrically coupled thereto via a control unit.

This member covers the same subrange of the range of vision of the eyes as the associated liquid crystal cell. It is a further advantage to arrange the liquid crystal cells of the lenses in lines and columns, wherein each of the light sensitive members associated with the lines and columns covers a definite angle of aperture. Taken all together the individual members of these lines and columns, respectively, define the respective horizontal and vertical angle of aperture, characterising the respective angle of vision range of the eyes.

An AND-member may be provided in the control units to permit a variation of the transmissivity of the liquid crystal cells when a respective signal is delivered by both of the light sensitive members which characterise the angle of vision range of the eyes in the horizontal and vertical directions. The determination of the liquid crystal cells which are to be operative in the formation of the range of vision is obtained by association of the subranges of the angle of vision range of the eyes covered by the light sensitive members to the respective liquid crystal cells.

The eye glasses according to the invention have the advantage of reducing the effect of glare radiation independently of the attitude of the head, the movement of the wearer's head, the location of the light source and, hence, of the angle of incidence.

In contrast to the previously known antiglare lenses, there are no obscured ranges in the absence of any glare radiation. Furthermore, the obscuring range is automatically adapted to the size of the light source and, hence, no neighbouring areas are covered and deprived of light.

In order that the invention may be more readily understood, reference is made by way of example only, to the accompanying drawings which illustrate diagramatically and by way of example two embodiments thereof and wherein:~ Fig. 1 is a block schematic diagram of antiglare glasses according to the invention; Fig. 2 is a schematic representation of one embodiment of a pair of antiglare glasses according to the invention; Fig. 3 is a schematic representation of a subdivision of the angle of the angle of vision range of a human subject's eye; Fig. 4 is a schematic view of a lens of the antiglare glasses; and Fig. 5 is a view of one embodiment of a lens of the antiglare glasses.

In Fig. 1 a block schematic of the components of the antiglare glasses shows a lens 1, which is subdivided by liquid crystal cells 2, a control unit 3 and a light sensitive member 4, both shown as functional blocks.

The liquid cells 2 are connected by signal line 6 to the control unit 3 which, in turn, is connected via a signal line 6' to the light sensitive member 4.

In operation, a bundle of light L impinges upon the light sensitive member 4 which delivers via the line 6' a signal to the control member 3, which, in turn, operates a liquid cell 21 so that the light transmissivity of the latter is reduced.

It is feasible, to control at least one liquid cell by the components 3 and 4.

Fig. 2 shows a practical reaiisation of the principle underlying Fig. 1 in the form of a pair of antiglare glasses comprising a frame 7 for mounting lenses 1, and arms 8 in which a plurality of the control members 3 (not visible) are installed.

The photosensitive members 4 are mounted in the lens frame 7 to face a (glaring) light source (not shown).

The lens 1 material can be selected from suitable optically corrected glass.

Advantageously, the light sensitive members 4 are arranged on the frame 7 in such a manner that each of them covers a definite subrange of the angle of vision of the eye, which angle is defined by the arrangement of the liquid crystal cells 2, and which together cover the complete angle of vision range of the eyes as described in more detail in connection with Fig. 3.

The electric signal lines 6 and 6' (not visible) are installed in the frame and in the lenses, respectively. The liquid crystal cells 2 do not differ from conventional liquid crystal cells and are, however, transparent in the non-operative state.

According to the function of such cells, the liquid crystals are enveloped by the lens material.

In Fig. 3 a subdivision of the range of vision of an eye 5 is schematically shown. The lens 1 comprises liquid crystal cells 2 and 22 which are separated from one another by auxiliary division lines 9. Each liquid crystal cell 2 (22) covers a section of the retina of the eye 5, and hence, determines a definite angle of vision range. The entire liquid crystal cells 2, 22 cover the entire angle of vision range of the eye 5.

The number of light sensitive members 4 (not shown in Fig. 3) which control the liquid crystal cells 22, 2, represent together the full angle of vision of the eyes 5. In practice however, it is not feasible at a reasonable expenditure precisely to align the light sensitive members 4 at a required angle.

Each of the light-sensitive members has tolerances of aperture range, that is, has a so called angle of vision aberration. To eliminate overlap of the angle of vision range of the light sensitive members 2, 22, it has been found that the angle of vision range of the light sensitive members corresponding to the individual liquid crystal cells 2, 22 should preferably be greater than double the angle of vision errors of these components.

In order to eliminate dead zones, that is, nondetected ranges, the angle of vision ranges have to be closely adjacent or slightly overlap, and they may only have a positive angle of vision error.

It is known from ophthalmology that the utilised range of view of the eyes only covers a small range of vision of a human subject's eyes.

In order to reduce the number of components it is therefore feasible to embody the liquid crystal cells 2 in such a manner that they are of increasing size towards the frame portion of the lens.

The shape of the liquid crystal cells can generally be selected at will, however, to avoid dead ranges, they have to form an uninterrupted face.

Fig. 4 shows an example of the subdivision of a lens 1 into individual liquid crystal cells and the arrangement of the associated light sensitive members 4. The lens 1 is divided into small square central liquid crystal cells 2, 24 and 25 and larger rectangular liquid cells 22, 23.

Each liquid crystal cell 2 is connected by (not visible) lines to a respective individual light sensitive member 4, that is, the number of light sensitive members 4 arranged in the frame equals the number of liquid crystal cells 2. The light sensitive members 4 are so aligned that they correspond to the respective subrange of the angle of vision range of the eyes 5 covered by the liquid crystal cells 2. Hence, a light sensitive member 42 is associated with the liquid crystal cell 22, a member 43 with the cell 23, a member 44 with the cell 24 and a member 45 with the cell 25.

When light impinges upon any of these members then the light transmissivity of the associated liquid crystal cell is varied.

Fig. 5 shows an embodiment of another feasible subdivision of the lens 1 into individual liquid crystal cells 2 and the arrangement of the associated light sensitive members 4. The liquid cells 2 are arranged in lines 10, etc. and columns 11 etc.

A light sensitive member 47 is associated with the column 11, and a light sensitive member 46 with the line 10.

Such an arrangement permits one to reduce the number of the required light sensitive members 4 and to simplify the requirements of the angle of vision range to be detected which is defined by a horizontal and a vertical angle of aperture.

The number of the required light sensitive members is determined by the number of lines and columns, that is, all liquid crystal cells 2 of a respective line or column are only electrically connected to one light sensitive member 4 via their control units 3.

The light sensitive members 4 associated with the lines have so to be mutually matched in their vertical angle of aperture that the entire vertical angles of aperture of the light sensitive members 4 correspond to the vertical angle of aperture of the vision range of the eyes 5.

A respective analogous requirement exists for the horizontal angle of aperture for the light sensitive members 4 associated with the columns.

The angles of aperture for the individual members are close together or even overlap in the already mentioned tolerances.

Since the angle of vision range of each liquid crystal cell 2 can be characterized by a horizontal and a vertical angle of aperture, each position of the liquid crystal cells 2 is defined by a light sensitive member 4 of the columns and the lines.

The control units 3 include AND-members to achieve this mode of control, which only permit the variation of the light transmissivity of the respective liquid crystal cells 2 when the two signals defining the position of the individual liquid crystal cell 2 are present.

Claims (11)

1. Antiglare glasses comprising a pair of lenses mounted in a lens frame, the faces of each of the lenses being constituted by a plurality of liquid crystal cells, control units provided for separate control of each individual liquid crystal of said plurality of liquid crystal cells, and a plurality of light sensitive members electrically connected to the control units and positioned such that, together, they are associated with the whole range of vision of the eyes of a wearer of the glasses with each light sensitive member being associated with a definite subrange of the angle of vision of the eyes.

2. Antiglare glasses as claimed in claim 1, wherein the liquid crystal cells are arranged on optically corrected lenses.

3. Antiglare glasses as claimed in claim 1 or 2, wherein the liquid crystal cells are of rectangular shape.

4. Antiglare glasses as claimed in claim 1,2 or 3 wherein the dimensions of the individual liquid crystal cells adjacent from the frame are larger than those liquid crystal cells in a central part of the lenses.

5. Antiglare glasses as claimed in any of claims 1 to 4, wherein each liquid crystal cell is electrically connected to a respective one light sensitive member via a control unit.

6. Antiglare glasses as claimed in any of claims 1 to 4, wherein each of the lenses is formed of a plurality of liquid crystal cells which are arranged in columns and lines.

7. Antiglare glasses as claimed in claim 6, wherein each line and column is connected to only one light sensitive member via the control units.

8. Antiglare glasses as claimed in claim 7, wherein the light sensitive members associated with each line of liquid crystals possess a definite vertical angle of aperture, the magnitude of said definite vertical angles of aperture corresponding to the entire vertical angle of aperture characterising the angle of vision range of the eyes.

9. Antiglare glasses as claimed in claim 7, wherein the light sensitive members associated with each column of the liquid crystal cells posess a definite horizontal angle of aperture which together establish the horizontal angle of aperture characterising the angle of vision range of the eyes.

10. Antiglare glasses as claimed in claim 7, wherein the control units include an AND-member so that the liquid crystal cells are driven only when signals from the light sensitive members of the respective column and line are applied.

11. Antiglare glasses substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.