in fig1 a , b , the light from one or more laser light sources 11 is brightness - modulated by a modulator 12 which is driven by driving electronics 13 which drive the modulator 12 and scanning unit 15 in accordance with the video signal 14 ( e . g ., rgb / rgy ) present at their input . the brightness - modulated laser light reaches a two - dimensional scanning unit 15 either via a light - conducting fiber 16 according to fig1 a or directly as is shown in fig1 b . by means of two - dimensional deflection , the scanning unit 15 generates a video picture which is projected onto the retina , according to fig1 a , via variable optics 17 either via a reflector in accordance with fig2 a and 2 b or by the optical system of the human eye 18 ( cornea and lens ) by means of direct projection which is not shown but is known per se from cited references . a signal train from the driver to the scanner ensures the required one - to - one geometrical correspondence of the image points of the video picture to the generated brightness steps of the modulator . in fig1 b , the image generated by the scanning unit is advantageously fed into an image - carrying fiber bundle 19 via variable optics . the image formed at the output location of the image - carrying fiber bundle 19 is projected onto the retina via the eye lens . the sequence of scanning unit 15 and variable optics 17 in the beam path of the optical imaging can also be switched or exchanged . fig2 a and 2 b show laser light source 21 , light guide 22 , spectacle frame 23 and scanner 24 which is fastened to the spectacle frame 23 , as well as a variable optical system 25 , wherein the sequence of scanner 24 and optical system 25 can also be switched . the spectacle glasses 26 are advantageously semitransparent , i . e ., the light distribution coming from the scanner 24 attached to the spectacle frame 23 is reflected by the spectacle glasses 26 but the surroundings can still be perceived . the reflective coating can also be wavelength - selective under certain circumstances . in a particularly advantageous manner according to the invention , the spectacle glasses 26 are divided into at least a first , preferably flat , zone z 1 for far vision testing and at least a second zone z 2 for near vision testing which is preferably constructed as a concave mirror . the two zones z 1 , z 2 can be constructed to be semitransparent . the first zone z 1 projects the light distribution of the scanner 24 in the direction of the eye 27 without influencing it , while the second zone for the eye 27 effects a projection of the scanner image from a defined , non - infinite distance , e . g ., from a distance of 40 cm . in this way , near vision testing can be performed according to the invention , wherein a viewing direction of the eye which is adapted to the natural near vision process is achieved by forming the second zone . in order to change from the far vision area to the near vision area , the generated scan image is displaced downward by an angle α from the first zone to the second zone . this is effected either in that the scanning unit 24 is constructed such that it may be operated manually or by motor so as to be tiltable by the above angle or by means of a purposely controlled deflection of the scanner 24 within the projection area by darkening parts of the image or altered deflection of the vertical scanning element . fig2 a contains a two - fold arrangement of light sources 21 , light guides 22 , scanners 24 and optics 25 in order to present images to both eyes 27 of the test subject simultaneously or alternately . particularly advantageous possibilities for determining subjective refraction are discussed hereinafter . by means of the system 25 constructed as variable optics , it is possible to purposely generate a convergence or divergence of the light projected onto the eye in an advantageous manner so that the far vision deficiency of the eye is compensated for based on information given by the patient in a reproducible and measurable manner , so that the test subject sees the image sharply . as was already mentioned , both zones z 1 , z 2 can be coated so as to be semitransparent so that a natural spatial impression and a relaxed viewing direction are made possible for the test subject . however , zones z 1 and z 2 can also be formed as a fully reflecting mirror . further examination methods for deficient vision are explained hereinafter with reference to the schematic drawings shown in fig3 a and 3 b in that variable optical elements are arranged in front of the eye . in this case , light sources 31 , light guides 32 , a scanning unit 34 fastened to the spectacle frame 33 , and exchangeable or variable elements 35 such as spherical lenses , cylindrical lenses , stokes lenses , prismatic lenses , and prism compensators are arranged between zones z 1 , z 2 of the spectacles and the eye 27 of the test subject . in fig3 a , for example , an optical element 35 of defined spherical and cylindrical effect is used in conjunction with zone z 1 and is supplemented in fig3 b by an add - on , not shown , with a positive action for near - vision testing in conjunction with zone z 2 . fig4 a and 4 b show the connection of the arrangement according to the invention in a schematic view with light source 41 ( with scanner and optics ), light guides 42 , spectacle glass with reflector 46 with known refraction spectacles 44 on a common frame 43 , wherein the refractive spectacles have holders for the use and exchange of test glasses 45 . instead of the test spectacles 44 , the invention can also work with the swivelable test glasses of a known phoropter arranged in front of the eye . in view of the fact that in such test spectacles or phoropters , the advantageous viewing direction of the test subject passes through the center of the test glasses , the spectacle glass 46 , when divided into zones z 1 , z 2 as in fig4 b , is advantageously put into different vertical positions as is shown schematically by the arrow in order to maintain this viewing direction for the different zones in far vision testing and near vision testing . when using a spectacle glass 46 which is not divided into zones in arrangements according to fig2 to 5 , a plane reflector can be used as spectacle glass and , as was mentioned above , an adjustment of the far vision area and near vision area can be effected by means of the variable optics arranged before or after the scanner . fig5 a and 5 b show the arrangement of the scanner 54 not on the spectacle frame 53 , but rather following the light source 51 and prior to a flexible light guide 52 , e . g ., an image - carrying fiber bundle , leading to the spectacle frame 53 , which arrangement is advantageous because it is lighter for the patient . the image generated by the scanner 54 is coupled into this flexible light guide 52 , preferably in a known manner by means of optics , not shown , wherein projection is effected on the retina via alternating optical components 55 , zones z 1 , z 2 , and the optical system of the eye 56 via the light guide end 521 fastened to the spectacle frame , optionally with variable optics following the latter . in a manner analogous to that described above , vision deficiency and other visual functions can also be determined with this system . further , the technical effect of the variable optics according to fig2 a , 2 b can also be transmitted into the area in front of the light guide input by arranging a variable optical system there . fig6 a shows a binocular test such as that which can be realized with an arrangement according to the invention in that the partial images are displaced relative to one another in a defined manner corresponding to the information given by the test subject by suitably controlling the modulator or the horizontal and / or vertical scanning elements . fig6 b shows a stereoscopic vision test , wherein the stereoscopic impression is altered by displaceable partial images . the different advantageous possibilities for determining vision functions were explained in the preceding with particular reference to an optical electronic system for direct projection on the retina . however , the described vision function tests can also be advantageously carried out by means of the spectacle type or helmet type frames mentioned in the beginning for monocular or binocular imaging of test images generated by screens via semitransparent or preferably relatively small full mirrors . in so doing , refraction can also be determined based on the information of the patent by means of intermediate optics which can be adjusted in a defined manner or exchanged . fig7 a and 7 b show a display 7 . 2 attached to the head of the observer , e . g ., by means of a strap 7 . 1 , wherein the image of two screens 7 . 3 is seen by the observer via suitable semitransparent or fully reflective deflecting elements 7 . 4 . while the foregoing description and drawings represent the present invention , it will be obvious to those skilled in the art that various changes may be made therein without departing from the true spirit and scope of the present invention .
an arrangement for use with a device that determines subjective refraction and / or performs other visual functions , comprises at least one light source , at least one light modulator for modulating the light source to produce modulated light , a driving unit for controlling said modulator to modulate the light source in accordance with video information corresponding to a video image , a two - dimensional deflector for deflecting the modulated light to produce a two - dimensional image , an optical transmitter for optically transmitting the light of the light source , and an optical projector for optically projecting the two - dimensional image onto a retina of an eye to be examined .