Classifications

• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
  • G02B27/0025—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00 for optical correction, e.g. distorsion, aberration
  • G02B27/0031—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00 for optical correction, e.g. distorsion, aberration for scanning purposes
• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B26/00—Optical devices or arrangements for the control of light using movable or deformable optical elements
  • G02B26/08—Optical devices or arrangements for the control of light using movable or deformable optical elements for controlling the direction of light
  • G02B26/10—Scanning systems
  • G02B26/101—Scanning systems with both horizontal and vertical deflecting means, e.g. raster or XY scanners
• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B26/00—Optical devices or arrangements for the control of light using movable or deformable optical elements
  • G02B26/08—Optical devices or arrangements for the control of light using movable or deformable optical elements for controlling the direction of light
  • G02B26/10—Scanning systems
  • G02B26/105—Scanning systems with one or more pivoting mirrors or galvano-mirrors
• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
  • G02B27/0025—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00 for optical correction, e.g. distorsion, aberration
  • G02B27/005—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00 for optical correction, e.g. distorsion, aberration for correction of secondary colour or higher-order chromatic aberrations
• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
  • G02B27/01—Head-up displays
  • G02B27/0101—Head-up displays characterised by optical features
• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
  • G02B27/10—Beam splitting or combining systems
  • G02B27/1006—Beam splitting or combining systems for splitting or combining different wavelengths
  • G02B27/102—Beam splitting or combining systems for splitting or combining different wavelengths for generating a colour image from monochromatic image signal sources
  • G02B27/104—Beam splitting or combining systems for splitting or combining different wavelengths for generating a colour image from monochromatic image signal sources for use with scanning systems
• • G—PHYSICS
  • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
  • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
  • G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
  • G09G3/02—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes by tracing or scanning a light beam on a screen
  • G09G3/025—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes by tracing or scanning a light beam on a screen with scanning or deflecting the beams in two directions or dimensions
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
  • H04N9/00—Details of colour television systems
  • H04N9/12—Picture reproducers
  • H04N9/31—Projection devices for colour picture display, e.g. using electronic spatial light modulators [ESLM]
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
  • H04N9/00—Details of colour television systems
  • H04N9/12—Picture reproducers
  • H04N9/31—Projection devices for colour picture display, e.g. using electronic spatial light modulators [ESLM]
  • H04N9/3129—Projection devices for colour picture display, e.g. using electronic spatial light modulators [ESLM] scanning a light beam on the display screen
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
  • H04N9/00—Details of colour television systems
  • H04N9/12—Picture reproducers
  • H04N9/31—Projection devices for colour picture display, e.g. using electronic spatial light modulators [ESLM]
  • H04N9/3141—Constructional details thereof
  • H04N9/315—Modulator illumination systems
  • H04N9/3164—Modulator illumination systems using multiple light sources
• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
  • G02B27/01—Head-up displays
  • G02B27/0101—Head-up displays characterised by optical features
  • G02B2027/0112—Head-up displays characterised by optical features comprising device for genereting colour display
  • G02B2027/0116—Head-up displays characterised by optical features comprising device for genereting colour display comprising devices for correcting chromatic aberration
• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
  • G02B27/01—Head-up displays
  • G02B27/0149—Head-up displays characterised by mechanical features
  • G02B2027/0165—Head-up displays characterised by mechanical features associated with a head-down display

Definitions

• the present invention relates generally to the field of displays and screens for projecting multicolored images.
• It relates more particularly to a device for generating a multicolored image formed of a set of pixels.
• a device for generating a multicolored image formed of a set of pixels comprising:
• control unit adapted to activate, for a given pixel of said image, each light source at respective activation times, each light source emitting, when activated by said control unit, a source light beam at said length emission wave;
• a first optical system directing said source light beams emitted towards beam deflection means adapted to deflect each source light beam in a variable deviation direction as a function of time.
• the source light beams are emitted simultaneously at identical activation times for a given pixel of the image and are deflected in the same direction of deflection towards a transparent display panel on which the light is formed. multicolored image.
• provision may furthermore be made to use in the device, in place of the transparent display panel, a diffuser intercepting each source light beam deviated and generating, at from it, a diffused light beam having a main direction of diffusion.
• the use of such a diffuser causes the light beams scattered at the same emission wavelength to exhibit different main directions of diffusion.
• the multicolored image generated by the device therefore changes color depending on the angle of view under which an individual would look at the diffuser.
• the device preferably comprises a second optical system arranged with respect to said beam deflection means so that the light beams scattered at the same emission wavelength have substantially parallel main directions of diffusion.
• the second optical system generally has optical aberrations, and in particular chromatic aberrations, axial and transverse, so that the light beams scattered at different wavelengths are spatially separated downstream of the diffuser and the second optical system.
• the multicolor image generated by the image generation device can then have iridescent pixels, which degrades the quality of the images generated.
• the present invention proposes an image generation device making it possible to compensate for, or even eliminate, the effects of chromatic aberrations.
• a device for generating a multicolored image formed of a set of pixels comprising:
• control unit adapted to activate, for a given pixel of said image, each light source at respective activation times, each light source emitting, when activated by said control unit, a source light beam at said length emission wave;
• a first optical system directing said emitted source light beams to beam deflection means adapted to deflect each source light beam in a variable deviation direction as a function of time;
• a scattering module intercepting each source light beam deflected in a given deflection direction to generate a scattered light beam having a main direction of diffusion
• said diffusion module comprising: a diffuser adapted to broadcast said deviated source light beams
• a second optical system arranged with respect to said beam deflection means so that the light beams scattered at the same emission wavelength have substantially parallel main directions of diffusion.
• said control unit activates, for said given pixel of the image, said light sources at respective activation times temporally offset with respect to one another so that the source light beams emitted towards said light sources Beam deflection are deflected in deflection directions angularly offset from one another.
• the beam deflection directions for the different wavelengths can be shifted so that said main directions of diffusion at the different lengths of the wave are substantially parallel to each other.
• the chromaticism of the second optical system is compensated by advancing or delaying the triggering of the light sources relative to one another.
• the control unit is therefore adapted to calculate, for each given pixel, advances or delays in triggering the light sources so that the deviations between the beam deflection directions at the different wavelengths, i.e. finally say the deviations of the angles that these deviation directions make with an optical axis of the second optical system, compensate for the spatial shifts between the scattered light beams corresponding to said given pixel.
• said beam deflection means comprises a plane mirror rotatable about a first axis of oscillation and a second axis of oscillation perpendicular to the first axis of oscillation, said plane mirror reflecting said source light beams in said directions of deviation depending on its orientation;
• said beam deflection means comprises a first plane mirror rotatable about a first axis of oscillation and a second plane mirror rotatable about a second axis of oscillation perpendicular to the first axis of oscillation, said first axis of oscillation; plane mirror reflecting said source light beams towards said second plane mirror according to a first orientation and said second plane mirror reflecting said source light beams in said deflection directions according to a second orientation;
• control unit determines, for said given pixel of the image, said respective activation instants of said light sources as a function of the oscillation speeds of the plane mirror or mirrors around the first and second oscillation axes;
• control unit determines, for said given pixel of the image, said respective activation instants of said light sources as a function of the orientation of the plane mirror or mirrors around the first and second oscillation axes;
• said second optical system comprises a single lens
• said lens is placed downstream of said diffuser
• said diffuser is plane and has a first face turned towards the beam deflection means and a second face opposite the first face, and said lens is contiguous on said second face;
• control unit determines, for said given pixel of the image, said respective activation instants of said light sources as a function also of the optical and geometric characteristics of said lens.
• the invention also proposes a head-up display comprising a device for generating a multicolored image as defined above.
• FIG. 1 is an overall view in partial section of a motor vehicle comprising a head-up display comprising a device for image generation according to the invention
• Figure 2 is a schematic view of the image generating device of Figure 1;
• FIG. 3 represents a sectional view of a diffusion module incorporated in the image generation device of FIG. 2;
• Fig. 4 is an exploded view showing the beam deflection means and the diffusion module of Fig. 3;
• FIG. 5 is an optical diagram of FIG. 3 showing how the angular offset of the deflection directions makes it possible to compensate for the transverse offsets due to the chromatism of the diffusion module;
• FIG. 6 represents a sectional view of a doublet of lenses that can be used in the production of a diffusion module according to another embodiment.
• FIG 1 there is shown a head-up display 1 equipping a vehicle, here a motor vehicle 2.
• this display 1 is intended to project images in the field of view of an individual 3 located inside the vehicle 2 (it is shown in Figure 1 that one of the eyes of the individual 3 ). It will be considered in the remainder of the description that this individual 3 is the driver of the motor vehicle 2.
• These images may include, for example, information relating to the vehicle 2 (speed, engine speed, fuel level, distance to other vehicles, etc.) or instructions as to the route to be followed by the vehicle 2 (in combination with an onboard navigation system for example).
• the display 1 comprises an image generating device for generating one or more images, in particular multicolored images, each image being formed of a set of pixels.
• the image generation device 30 receives signals from the on-board computer (not shown) of the vehicle 2 and generates function of these signals, from each pixel of the generated image (see for example the pixel 4 of FIG. 1), a primary light beam 7 (only a primary light ray starting from the pixel 4 of the image is represented on FIG. 1) showing a scene to be projected in the driver's field of view 3.
• the display 1 also comprises an optical projection system of the scene to the driver 3 located inside the vehicle 2.
• This optical projection system comprises in particular a reflecting mirror 8 and a combiner 9 (see FIG. 1).
• the reflecting mirror 8 is here a spherical mirror but alternatively, it could be a plane mirror or a mirror of parabolic, elliptical or aspherical shape.
• the reflecting mirror e intercepts the primary light beam 7 generated and reflects the primary light beam 7 towards the combiner 9.
• the combiner 9 is here disposed between the windshield 23 of the vehicle 2 and the eyes of the driver 3 and is mounted on a base 14 placed in an instrument panel 15 of the vehicle 2.
• the combiner may be provided between the combiner and the base, the combiner adjusting means for changing its position and / or its orientation relative to the dashboard.
• the combiner 9 intercepts the primary light beam 7 reflected by the reflecting mirror 8 and reflects it itself towards the conductor 3 so as to form an image 16 of the scene generated by the image generation device 30 which is visible by the driver 3.
• the image generating device 30, the reflecting mirror 8 and the combiner 9 are arranged relative to one another so that the display 1 projects the image 16 of the scene into the field of view of the image. driver 3 but outside the vehicle 2, here at the front of the hood 17 of the vehicle 2.
• This image 16 of the scene is formed, in a preferred direction 18, at a distance from the conductor 3 which is generally between 1, 8 and 2.5 meters.
• the combiner 9 is partially transparent, the image 1 6 of the scene is visible by the driver 3 without it having to divert from way too much the look of the road when in driving situation.
• this image generation device 30 firstly comprises a plurality of monochromatic light sources 31, 32, 33, here three in number.
• these light sources 31, 32, 33 are monochromatic insofar as their emission spectrum has an emission peak (maximum intensity value) for a precise emission wavelength ⁇ 0 having a spectral width ⁇ 0 such that ( ⁇ 0 ) 2 / ⁇ 0 »1 micron.
• a light source is monochromatic if its temporal coherence length is greater than 1 micron.
• a light source emitting laser radiation is an example of a monochromatic source.
• the emission wavelengths of the different light sources are chosen so as to maximize the space of accessible colors by superposing one or more wavelengths.
• These light sources 31, 32, 33 are activated by a control unit 20 which receives signals from the on-board computer (not shown) of the vehicle 2.
• Each light source 31, 32, 33 emits, when activated by the control unit 20, a source light beam 1 1, 1 2, 1 3 at the corresponding emission wavelength of the source.
• the first light source Trunk group 1 1 is therefore blue to the wavelength ⁇ 0, B
• the second source light beam 12 is therefore green to the wavelength ⁇ 0, ⁇
• the third light beam source 13 is red at the wavelength ⁇ 0 , R.
• collimation means are provided just downstream of the light sources 31, 32, 33 to collimate the light beams.
• sources 1 1, 12, 13 which at the output of the light sources 31, 32, 33 are strongly divergent.
• the source light beams 1 1, 12, 13 are here three parallel beams separated laterally from each other due to the separation of the light sources 31, 32, 33.
• the image generation device 30 comprises a first optical system 34, 35, 36 for superimposing and directing the three source light beams 1 1, 12, 13 emitted by the light sources 31, 32, 33 towards beam deflection means 50.
• this first optical system comprises three mirrors 34, 35, 36.
• these mirrors 34, 35, 36 are plane dichroic mirrors, oriented for example at 45 ° with respect to the direction of propagation of the source light beams 1 1, 12, 13 so that they are reflected with an angle 90 ° to the beam deflection means 50.
• the mirrors 35, 36, 37 are preferably arranged with respect to the light sources 1 1, 12, 13 and with respect to one another so that the source light beams 1 1, 12, 13 are superimposed and then form together a polychromatic light beam.
• These beam deflection means 50 then deviate each source light beam 1 1, 12, 13 in a direction of deviation variable as a function of time.
• the beam deflection means here comprise (see FIG. 2) an oscillating mirror 50 movable plane rotated about two crossed oscillation axes: a first oscillation axis 51 and a second oscillation axis 52 which is perpendicular to the first oscillation axis 51.
• This two-dimensional oscillation mirror 50 may for example be of the "MEMS” (acronym for “Micro-Electromechanical System”) type.
• Such oscillating mirror 50 MEMS has according to one of the oscillation axes 51, 52 a uniform oscillation movement at a low frequency, generally less than 1000 Hz, typically between 50 and 100 Hz.
• the oscillating mirror 50 MEMS has a resonant oscillation movement at a high frequency, generally greater than 10 kHz, here between 20 and 30 kHz. Due to the resonance, the rotation speed of the oscillating mirror 50 along this last axis is not uniform but is non-linear:
• the source light beams 1 1, 12, 13 are incident on the oscillating mirror 50 at the same point of intersection 53 of the oscillating mirror 50 corresponding to the intersection of the oscillation axes 51, 52.
• the oscillating mirror 50 then reflects the source light beams 1 1, 12, 13 in respective deflection directions according to the orientation (ie angles) of the oscillating mirror 50 with respect to the oscillation axes 51, 52.
• the beams bright sources 1 1, 12, 13 reflected and deflected by the oscillating mirror 50 will respectively referenced 71, 72, 73 in the following description.
• the beam deflection means may comprise two MEMS mirrors: a first plane mirror movable in rotation about a first oscillation axis and a second plane mirror movable in rotation about a second oscillation axis perpendicular to the first oscillation axis.
• the first plane mirror reflects the source light beams in the direction of the second plane mirror according to a first orientation relative to the first axis of oscillation and the second plane mirror reflects the source light beams reflected by the first plane mirror in deflection directions which depend on a second orientation with respect to the second oscillation axis.
• the deviated source light beams 71, 72, 73 have variable directions of deviation as a function of time and in this case periodically as a function of the movement of oscillation of the oscillating mirror 50.
• the deviated source light beams 71, 72, 73 thus perform a scanning movement (see line 5 in FIG. 2).
• the image generation device 30 then also comprises a diffusion module 40 for intercepting each deviated source light beam 71, 72, 73 in a given deflection direction to generate a scattered light beam having a main direction of diffusion.
• This diffusion module 40 comprises, on the one hand, a diffuser 41, and, on the other hand, a second optical system 42 (see FIG. 3) which is formed in the embodiment shown in FIGS. single lens, preferably convergent, for example of plano-convex type.
• the lens 42 is here placed downstream of the diffuser 41 but, alternatively, it could be placed upstream of the diffuser.
• the diffuser 41 is here a diffuser of the "Multi-Lens Array” (MLA) type.
• Such a diffuser is composed of a multitude of microlenses, a given radius and arranged next to each other in a regular arrangement, for example of the honeycomb type, while respecting a gap between the center of each micro-lens about 100 ⁇ .
• This type of diffuser makes it possible to open the diffusion indicator of the deviated source light beams 71, 72, 73 incident on the diffuser 41 by defocusing them, the angle of opening of the diffusion cone being directly related to the focal distance of each micro-lens).
• FIG. 4 is an exploded view showing the oscillating mirror 50, and the diffusion module of FIG. 3 where the diffuser 41 has been separated from the lens 42
• the diffuser 41 is preferably flat and has a first face 43 facing the oscillating mirror 50 and a second face 44 opposite the first face 43
• the lens 42 is contiguous on the second face 44, here by the flat face 45 of the lens 42 opposite its convex face 46.
• the diffuser 41 of the diffusion module 40 is intended to diffuse the source light beams deflected by the oscillating mirror 50.
• FIG. 4 shows a deviated source light beam 74 (for example emitted by the second light source emitting in the green) by the oscillating mirror 50 towards the diffuser 41 in a given deflection direction. through the diffuser 41 (see rays 75 and 76 in Figure 4).
• a deviated source light beam 74 for example emitted by the second light source emitting in the green
• the lens 42 is arranged with respect to the oscillating mirror 50 so that the scattered light beams 7 at the same emission wavelength have directions mainly parallel diffusion patterns.
• the lens 42 is arranged so that its object focus coincides with the point of intersection 53 of the oscillating mirror 50 from which all the source light beams are reflected. deflected 71, 72, 73.
• the second optical system here the plano-convex lens 42 has chromatic aberration.
• the control unit 20 activates the light sources 31, 32, 33 at activation times t B , t v , t R respective ones temporally offset from each other so that the source light beams 1 1, 12, 13 emitted towards the beam deflection means 50 are deflected in deviation directions angularly offset relative to each other.
• control unit 20 is adapted to desynchronize the laser pulses between the red, green and blue laser diodes, so that for the same pixel on arrival, the scattered light beams emerge in the same direction of this same pixel. It is therefore a question of advancing or delaying the triggering of the light sources relative to each other as a function of the value of the chromaticism defect of the second optical system 42.
• FIG. 5 makes it possible to understand how the time offsets between the different light sources 31, 32, 33 can be determined.
• FIG. 5 only shows the lens 42 as well as the three deviated source light beams 71, 72, 73 coming respectively from the first light source 31 (blue laser diode), from the second light source 32 (green laser diode), and the third source bright 33 (red laser diode).
• These three deviated source light beams 71, 72, 73 are deflected by the oscillating mirror 50 from the point of intersection 53 in three deflection directions angularly offset and respectively marked by the three angles ⁇ , ⁇ 2 , ⁇ 3 with respect to the optical axis 47 of the lens 42 of the diffusion module 40.
• the transverse offsets respectively between the source light beam deviated 71 to the first wavelength (blue) and the source light beam deflected 72 to the second length d wave (green), and between the source light beam deflected 73 at the third wavelength (red) and the source light beam deflected 72 at the second wavelength (green).
• the lens 42 is located at a distance D (referenced 80 in FIG. 5) from the point of intersection 53 equal to the objective focal length of the lens 42, and more precisely to the objective focal length of the lens 42 at the second emission wavelength ⁇ 0 , ⁇ which is taken here as the reference wavelength with respect to which all time offsets will be calculated.
• transverse offsets 81, 83 depend in particular on:
• the optical refractive index of the lens 42 as a function of the wavelength that is to say the material constituting this lens
• the geometry of the lens 42 in particular the radii of curvature of its two faces 45, 46 and its thickness at the center 48 (see FIG. 5);
• the deflection direction ⁇ 2 for the reference wavelength corresponding to the given pixel of the image.
• the optical refractive index is higher in blue than in red, so that blue rays are more refracted than red rays through the lens 42.
• the transverse offset 81 of the blue is positive (corresponding to an angular offset ⁇ 1 - ⁇ 2 positive, case of FIG. other transverse offsets, here the transverse offset 83 of the red is negative (corresponding to an angular offset ⁇ 3 - ⁇ 2 negative).
• the third light source 33 (red) is activated by the control unit 20 before the second light source 32 (green). which is itself activated before the first light source 31 (blue).
• the time offsets ⁇ ⁇ , At R respectively between the instant of activation te of the first light source 31 and the activation time tv of the second light source 32, and between the instant of activation RR of the third light source 33 and the activation time t v of the second light source 32 are determined by the control unit 20 as a function of the oscillation speeds with respect to the two oscillation axes 51, 52.
• control unit 20 determines, for each pixel of the image, the activation instants t B , t v , t R as a function also of the optical and geometric characteristics of the lens 42, in particular as a function of its refractive index and its geometry (see above).
• the resonance characteristics of the oscillating mirror 50 are known so that the variation of the rotational speed ⁇ ( ⁇ ) of the oscillating mirror 50 is known as a function of the time t (see above). It is therefore possible from the above relation to deduce the value of the time shift At R for the transverse shift dx R adapted to compensate for the chromaticism of the lens 42, here for the red. The same deduction can be made for the transverse shift dxe of blue compared to green.
• the offsets temporal ⁇ , AÎR between the different activation times te,, ÎR are not linear either in time.
• control unit 20 determines, in an advantageous embodiment, for each pixel of the image, the activation times ÎR, tv, and light sources 31, 32, 33 depending on the orientation of the oscillating plane mirror (s) 50 about the first and second oscillation axes 51, 52.
• control unit 20 it is possible to provide a feedback loop enabling the control unit 20 to be servocontrolled as a function of a signal representative of the actual orientation of the oscillating mirror 50 with respect to a reference position, by example its rest position.
• control unit can activate each light source independently of each other at temporally offset activation times which correspond exactly to the optimal deviation directions to compensate for the transverse color of the lens.
• the second optical system could for example comprise several optical lenses.
• the second optical system 90 may comprise two distinct optical lenses 91, 92 that have predetermined refractive indices and constringences so as to minimize the chromatic aberrations of the second optical system.
• first optical lens 91 having a first constringence greater than 50 in absolute value
• second optical lens 92 having a second constringence of less than 50%. absolute value
• the first lens 91 may be made of crown glass and the second lens 92 of flint glass.
• the radii of curvature and the thicknesses of the lenses 91, 92 can also be optimized.
• the two lenses 91, 92 may be contiguous to each other (case of Figure 6) or separated. They may be made of an organic or polymeric material, such as polycarbonate or polymethylmethacrylate, or in a mineral material made of glass.
• This may be advantageous for reducing, for the same pixel of the image, the angular offsets between the deflection directions of the different deviated source light beams, which avoids the overlap of the beams for two neighboring pixels.
• the second optical system could include three or four thin lenses.

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• Physics & Mathematics (AREA)
• Optics & Photonics (AREA)
• General Physics & Mathematics (AREA)
• Engineering & Computer Science (AREA)
• Multimedia (AREA)
• Signal Processing (AREA)
• Computer Hardware Design (AREA)
• Theoretical Computer Science (AREA)
• Mechanical Optical Scanning Systems (AREA)

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• 2016
  • 2016-05-04 FR FR1654075A patent/FR3051050B1/fr active Active
• 2017
  • 2017-04-28 EP EP17720130.8A patent/EP3452862A1/de not_active Withdrawn
  • 2017-04-28 WO PCT/EP2017/060215 patent/WO2017191053A1/fr unknown

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