WO2015028992A1 - Dispositif optique destiné à transmettre et émettre de la lumière - Google Patents

Dispositif optique destiné à transmettre et émettre de la lumière Download PDF

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Publication number
WO2015028992A1
WO2015028992A1 PCT/IB2014/064175 IB2014064175W WO2015028992A1 WO 2015028992 A1 WO2015028992 A1 WO 2015028992A1 IB 2014064175 W IB2014064175 W IB 2014064175W WO 2015028992 A1 WO2015028992 A1 WO 2015028992A1
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WO
WIPO (PCT)
Prior art keywords
optical system
optic
light
main face
optical
Prior art date
Application number
PCT/IB2014/064175
Other languages
English (en)
Inventor
Varun Akur Venkatesan
Original Assignee
Varun Akur Venkatesan
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
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Application filed by Varun Akur Venkatesan filed Critical Varun Akur Venkatesan
Publication of WO2015028992A1 publication Critical patent/WO2015028992A1/fr

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Classifications

    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/0001—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems
    • G02B6/0011—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems the light guides being planar or of plate-like form
    • G02B6/0033—Means for improving the coupling-out of light from the light guide
    • G02B6/0035—Means for improving the coupling-out of light from the light guide provided on the surface of the light guide or in the bulk of it
    • G02B6/0036—2-D arrangement of prisms, protrusions, indentations or roughened surfaces
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/0001—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems
    • G02B6/0011—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems the light guides being planar or of plate-like form
    • G02B6/0033—Means for improving the coupling-out of light from the light guide
    • G02B6/0035—Means for improving the coupling-out of light from the light guide provided on the surface of the light guide or in the bulk of it
    • G02B6/0045—Means for improving the coupling-out of light from the light guide provided on the surface of the light guide or in the bulk of it by shaping at least a portion of the light guide
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/0001—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems
    • G02B6/0011—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems the light guides being planar or of plate-like form
    • G02B6/0033—Means for improving the coupling-out of light from the light guide
    • G02B6/0035—Means for improving the coupling-out of light from the light guide provided on the surface of the light guide or in the bulk of it
    • G02B6/0045—Means for improving the coupling-out of light from the light guide provided on the surface of the light guide or in the bulk of it by shaping at least a portion of the light guide
    • G02B6/0046—Tapered light guide, e.g. wedge-shaped light guide
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/24—Coupling light guides
    • G02B6/26—Optical coupling means
    • G02B6/34—Optical coupling means utilising prism or grating

Definitions

  • the invention relates to directing light for emission, more specifically optical system for light transmission and emission.
  • light is emitted using optics such as a lens, diffusers and light guides.
  • Structured light such as images, image patterns and light fields are emitted using displays and projectors.
  • the display system is bulky and occupies a lot of space. As the field of view becomes larger, the distance between the projector and the screen increases, making the device bulky. Bulky configurations are undesirable since they are difficult to work with, cost more and are less portable. Transportation and installation of bulky devices cause additional problems and cost. In the case of display systems such as Liquid crystal displays (LCDs), the cost of large systems is prohibitive.
  • LCDs Liquid crystal displays
  • the object of this invention is to provide an optical system that allows for emission of light to a large area from a very short distance.
  • optical system comprising a transparent optic defining an optical volume, the transparent optic comprising a first main face adapted to emit light and a first turning optic for turning the light inside the optical volume such that the light exits the optical volume after reaching the critical angle.
  • the light is internally reflected successively within the optical volume.
  • the transparent optic further comprises a second main face being opposite to the first main face, the first turning optic being arranged on a portion of one of the first main face and the second main face.
  • the transparent optic further comprises one or more side faces configured to admit light inside the optical volume.
  • the first turning optic is configured to turn the light to a direction different from the geometric normal of the first main face.
  • the first turning optic is configured to turn the light to a direction different from the geometric normal of the second main face.
  • the first turning optic comprises an array of geometrical structures for turning the light.
  • the geometrical structures are adapted to selectively alter the direction of reflection.
  • the geometrical structures are adapted to selectively alter the direction of reflection via a motion of one or more geometrical faces of the geometrical structures.
  • one or more faces of the geometrical structures are programmed to vibrate at a desired frequency.
  • one or more faces of the geometrical structures are altered by micro -fluidic actuation.
  • the array of geometrical structures are prisms.
  • the first turning optic is configured to simultaneously direct portions of the incident light in more than one directions.
  • the first turning optic is made of a material of laterally varying refractive index.
  • the first turning optic is made of one or more layers of axially varying refractive index.
  • the first turning optic is curved in one or more directions. According to yet another embodiment, the first turning optic is arranged on a portion of one of the first main face and the second main face. According to yet another embodiment, wherein the first turning optic is a made of an elastic material.
  • the first turning optic is made of a flexible material. According to yet another embodiment, the first turning optic is a film
  • the first turning optic is a layer formed on a portion of one of the first main face and the second main face.
  • the second main face is parallel to the first main face.
  • the second main face is at an angle to the first main face.
  • the optical volume is formed of a solid.
  • the optical volume is formed of a fluid.
  • At least a portion of the optical volume is formed of vacuum.
  • the transparent optic is flexible.
  • the transparent optic is stretchable.
  • At least one of the first main face, the second main face and the first turning optic is coated with an antireflection coating.
  • the optical system further comprises a secondary turning optic for directing the light at a desired angle out of the first main face, the secondary turning optic coupled to the first main face via a layer having a refractive index lower than the optical volume.
  • the optical system further comprises an additional transparent optic defining an additional optical volume and a coupler adapted to receive the light emerging from the additional optical volume after internal reflection and direct the light onto the transparent optic, wherein the transparent optic is adapted to admit the light directed by the coupler.
  • the optical system further comprises a wavelength selective filter arrange between the first turning optic and the optical volume.
  • the optical system further comprises a coupling device to direct light from a source onto a portion of the first main face.
  • the optical system further comprising a plurality of light source assemblies illuminate a target from multiple viewpoints.
  • a portion of the incident light on the second main face is transmitted through the first main face.
  • the first turning optic is removably attached on to the second face.
  • the geometrical structures are adapted to reflect a first portion of the incident light and transmit a second portion of the incident light.
  • the transparent optic comprises a propagation area comprising a triangular geometrical profile, wherein the light propagates through internal reflections between the first main face and the second main face in the propagation area.
  • the optical system further comprises a plurality of transparent optics arranged in series, wherein at least one said transparent optic is configured to direct a portion of the light admitted from the light source assembly to at least one another said transparent optic.
  • the transparent optic is configured to admit light from a plurality of different angles and direct the light onto the first turning optic at different positions corresponding to different angles.
  • the transparent optic comprises a cylindrical geometrical structure.
  • FIG 1 illustrates an exemplary optical system according to an embodiment herein
  • FIG 2 illustrates an exemplary optical system in combination with a light source assembly according to an embodiment herein; illustrates a transparent optic and a first turning optic in more detail according to an embodiment herein; illustrates an array of geometrical structures of a first turning optic according to another embodiment herein; illustrates an optical system according to an embodiment herein; illustrates an exemplary coupler according to one embodiment herein; illustrates a transparent optic according to an embodiment herein; illustrates a transparent optic according to an embodiment herein; illustrates a transparent optic comprising a curved geometry according an embodiment herein; illustrates an optical system for transmitting light from a plurality of light source assemblies from different angles according to an embodiment herein; illustrates an exemplary example of a first turning optic according to an embodiment herein; illustrates a first turning optic according to an embodiment herein; illustrates an exemplary side view of a transparent optic, wherein the optical volume defines a plurality of zones due to the first turning optic according to an embodiment herein; illustrates a transparent optic according to an embodiment herein; illustrates a
  • FIG 20 illustrates an optical system according to an embodiment herein
  • FIG 21 illustrates an optical system according to an embodiment herein
  • FIG 22 illustrates an optical system according to an embodiment herein
  • FIG 23 illustrates an optical system according to an embodiment herein
  • FIG 24 illustrates an optical system according to an embodiment herein
  • FIG 25 illustrates an optical system according to an embodiment herein
  • FIG 26 illustrates an optical system according to an embodiment herein
  • FIG 27 illustrates an application of an optical system for light coupling and mixing according to an embodiment herein
  • FIG 28 illustrates an application of an optical system for frustrated total internal reflection according to an embodiment herein
  • FIG 29 illustrates an application of an optical system in gage reader according to an embodiment herein
  • FIG 30 illustrates an application of an optical system for filtering and combining different spectra according to an embodiment herein;
  • FIG 31 illustrates an application of an optical system comprising a plurality of transparent optics according to an embodiment herein;
  • FIG 32 illustrates an optical system according to an embodiment herein
  • FIG 33 illustrates an optical system according to an embodiment herein
  • FIG 34 illustrates an optical system according to an embodiment herein
  • FIG 35 illustrates an optical system according to an embodiment herein
  • FIG 1 illustrates an optical system according to one embodiment of the present invention.
  • the optical system 10 comprises a transparent optic 12 defining an optical volume 37 and a first turning optic 13.
  • the optical system 10 emits light to a scene 15 in front of it.
  • Light from a source enters the optical volume 37.
  • Upon entering the optical volume 37 via a side face 36 light propagates via internal reflection until it reaches the first turning optic 13 and gets turned in a manner to exit the optical volume 37.
  • a secondary turning optic alters the angle of exit of light from the optical volume 37.
  • optical volume herein refers to the volume wherein the light undergoes to and forth reflection before exiting the transparent optic 12.
  • FIG 2 discloses an optical system 10 in combination with a light source assembly 11 according to an embodiment herein.
  • the light exiting the optical volume 37 via the main face 35 is redirected by a secondary turning optic 14.
  • the secondary turning optic 14 directs the light exiting the optical volume 37 from the exit angle to a desired angle. In another embodiment, the exit angle is glancing.
  • the secondary turning optic 14 is coupled to the first main face 35 via a layer 48 having a refractive index lower than the refractive index of the optical volume 37.
  • the light from a light source or projector 11 enters the optical volume 37 from the side face 36 via a conditioning optic 38, for example, a lens. Once within the optical volume 37, the light travels in a confined manner between the second main face 34 and the first main face 35 to reach a first turning optic 13 which is arranged on at least a portion of the second main face 34.
  • the first turning optic 13 turns the light such that difference between the incidence angle and the critical angle is reduced.
  • the rays 39 that reach or exceed the critical angle early exits the optical volume 37 at an earlier location whereas rays 40 those reach later 40 exits the volume later. These rays 39 and 40 reach a target surface such as a zone to be illuminated or the eyes of a viewer.
  • the optical system 10 described herein allow for projection of an image (2D or 3D) over a large viewing area. This is due to a piece-wise spatial relationship preserving aspect of the optical system 10.
  • the spatial relationships of light from within a subset of the scene are preserved when the light reaches a scene 15. While the spatial relationships of the whole scene may be preserved in some embodiments, it is sufficient in other embodiments that they are preserved within a subset of the scene 15 while not necessarily the whole scene 15.
  • the optical system 10 is also capable of preserving angular relationships in a piece wise manner. This provides the advantage of the optical system 10, emitting light to a large scene 15 from a short distance as opposed to conventional projectors which need a certain throw distance. Conventional systems, such as a lens do not provide the advantage of reduction in the distance. Also, the lens has the disadvantage of being bulky. The embodiment described herein, thus, allows for a compact and flat configuration at a low cost for a large field of view display.
  • the propagation of light from the source 11 is illustrated by the rays 39 and 40.
  • the rays 39 and 40 upon reaching the side face 36 enter the optical volume 37 and continue to propagate internally until they reach the first turning optic 13.
  • the ray 39 is incident at an angle so as to exit the optical volume 37 from a location proximal to the side face 36
  • the ray 40 is incident at an angle so as to exit the optical volume from a location distal from the side face 36.
  • the rays 39 and 40 upon reaching the first turning optic 13 undergo a change in the angle when they are reflected back into the optical volume 37. Each reflection from the turning optic 13 could decrease the difference between the angle of incidence and the critical angle.
  • the rays 39 and 40 undergo successive reflections within the optical volume 37, wherein the reflections caused by the first turning optic 13 causes change in angle and the reflections beyond the portion of the first turning optic 13 does not cause change in angle.
  • the spatial relationships are converted into angular relationships and preserved.
  • the tertiary optic 38 transfers the angular spread of rays 39 and 40 onto the side face 36 and couples the light from the light source 11 such as a projector.
  • FIG 3 illustrates a transparent optic 12 and a first turning optic in more detail according to an embodiment herein.
  • the first turning optic 13 comprises an array of geometrical structures 105 for turning the light.
  • an array of prisms is illustrated as the geometrical structure 105.
  • the light rays 104 reaching the first turning optic 13 continues into the geometrical structure 105 and is reflected as the light ray 106 with an added turn angle.
  • the reflection of light is determined by the geometry of second main face 34 and first main face 35 as depicted by the light rays 102, 103 and may not experience the added turning angle imparted by the first turning optic 13.
  • the first turning optic 13 may be clamped or glued to a transparent optic 12.
  • the first turning optic 13 can may be embossed, inscribed or machined on the second main face 34 of the transparent optic 12.
  • the first turning optic 13 can be embossed, inscribed or machined on the second main face 34 of the transparent optic 12.
  • the transparent optic 12 can be implemented using a glass slab wherein the first main face and the second main face may be parallel. This provides the advantage of using the existing installations of transparent optics for illumination.
  • the transparent optic can also be implemented using devices wherein the first main face and the second main face are not parallel, i.e., are at an angle.
  • FIG 4 illustrates an array of geometrical structures of the first turning optic according to another embodiment herein.
  • an array of trapezoidal structures is illustrated as geometrical structures 105.
  • the light rays 140 and 143 are reflected by the trapezoidal structures with the added turning angle.
  • the first turning optic 13 can also comprise varying refractive index materials, laterally varying geometries and laterally varying graded refractive index materials.
  • the first turning optic 13 can also comprise of layers of thin films of varying refractive indices, each of which could further comprise of laterally varying refractive index.
  • a further compact form of the optical system 10 is achieved using an additional transparent optic 20 and a coupler 19.
  • the additional transparent optic 820 defines an additional optical volume 37b.
  • the optical volume 37a and the additional optical volume 37b defined by the transparent optic 12 and the additional transparent optic 20 together define the optical volume 37.
  • the transparent optic 12 comprises the first turning optic 13.
  • Light rays from the projector/light source 11 enter the additional optical volume 37b and propagate towards the coupler 19.
  • the coupler 19 will re-direct the light from the additional transparent optic 20 to the transparent optic 12.
  • the light entering the optical volume 37a gets turned by the first turning optic 13 in a manner to exit the optical volume 37a.
  • the embodiment provides the advantage of compacting the overall form factor towards smaller area footprint when the trade-off is favorable. For example, in fields of proximate imaging in the context of machine vision and industrial automation, the size of the optical system may be restricted by the space available.
  • FIG 6 illustrates an exemplary coupler according to one embodiment herein.
  • the coupler 19 comprises a pair of prism 21a and 21b that reverse the light after shifting in one direction.
  • a portion 12a of the transparent optic 12 comprises a geometry of a wedge.
  • the wedge geometry of the portion 12a is used for turning the light rays 39 in conjunction with the first turning optic 13. Since the first turning optic 13 is dedicated to turning the light rays 39 and reduce angle between the critical angle for exit, a higher flexibility is possible in the case of wedge designs.
  • the wedge geometry of the portion 12a may taper in the opposite direction, as illustrated in FIG 8.
  • the transparent optic 12 may comprise a curved geometric structure.
  • the light rays 39, 40 from the source 11 reach the curved geometrical structure of the optical volume 37 and meet the first turning optic 13.
  • the first turning optic 13 turns the light rays 39, 40 such that they exit from the first main face 34.
  • the first turning optic 13 is placed on the convex face of the optical volume 37 in order to accept light from the concave side.
  • An opposite configuration is achievable by changing the location of the first turning optic 13 from the convex to the concave face, imaging can be performed on the convex surface. Since the optic can be concave or convex, it can be placed in a flush mount configurations over existing building structures such as curved walls and faces.
  • a plurality of light source assemblies may be used for transmitting light to a specific target from different angles.
  • the optical system 10 comprises the light source assembly 11 and an additional light source assembly 101 for transmitting light from different angles.
  • Different light rays depicted as 39 and 40, from different angles, reach the first turning optic 13 at different positions.
  • the tertiary optics 38 and 107 are provided for enabling the light source assembly 11 and the additional light source assembly 101 respectively for transmitting the light rays 39, 40 from different angles.
  • a plurality of light source assemblies i.e., the light source assembly 11 and the light source assembly 101 allow for transmission of light to a specific target from different angles.
  • FIG 11 illustrates an exemplary example of a first turning optic 13 according to an embodiment herein.
  • a plurality of prismatic or trapezoid structures arranged adjacent to each other but curved in a lateral direction are illustrated as the geometrical structures 105 of the first turning optic 13.
  • the curvature provides the advantage of projecting light at multiple angles to the scene and correct parameters such as aspect ratio, distortion, and the like.
  • the curved geometrical structures 105 turn the incident light rays 39 such that the light rays 39 are turned into a plurality of different planes.
  • a plurality of prismatic or trapezoid structures arranged adjacent to each other but curved in the lateral direction are illustrated as the geometrical structures 105 of the first turning optic 13.
  • the first turning optic 13 comprise one or more secondary turns 116.. An intended effect of such arrangement is to segregate the illumination exit into areas of illumination where the exit angle is different for different zone.
  • the light ray 39 is incident at a particular angle and exits at a different angle. This provides the advantage of transmitting light to a target from different directions or angles.
  • FIG 13 illustrates an exemplary side view of a transparent optic 12, wherein the optical volume 37 defines a plurality of zones formed due to the first turning optic 13 of FIG 11 and FIG 12. As depicted, the optical volume 37 defines two zones 123 and 124 wherein rays 39 reach the target at a certain angle whereas rays 39' reach the target at different angles. This provides the benefit of transmitting light from different directions to the target.
  • FIG 14 illustrates a transparent optic according to an embodiment herein.
  • an optical volume 37 defined by the transparent optic 12 is hollow.
  • the optical volume 37 being hollow comprises additional layers of optics.
  • the additional layers of optics 104 may be arranged on any one of the internal surface of the transparent optic 12 or on both the internal surfaces.
  • the optic 104 may be a turning optic.
  • FIG 15 illustrates an embodiment wherein a series of optical sheets may be arranged into the hollow optical volume 37.
  • structural members may be used to support the optical sheets in position.
  • Such an embodiment also allows for flexibility and stretch-ability.
  • one or more sides of the internal surfaces may be coated with an antireflection coating.
  • the optical device can be used as a large signage, mobile phones and computing devices.
  • the transparent optic 12 comprises three optical surfaces. Light enters through the side face 36 and is redirected to be contained between the two surfaces 1002 and 1001 and then exits the transparent optic 12 on interacting with a portion 1003.
  • the portion 1003 comprises a polygonal structure configured in such a manner that light reflecting between the two surfaces 1002 and 1003 does not change the relative angle of reflection, whereas on interacting with the portion 1003, the angle is increased or decreased.
  • the portion 1003 may comprise structures comprising a quadrilateral cross section.
  • FIG 17 illustrates an optical system 10 according to another embodiment herein.
  • the transparent optic 12 defines an optical volume comprising a cylindrical geometrical structure.
  • the optical volume 37 comprises a plurality of layers of optics on one of either of the internal surfaces.
  • the first turning optic 13 is arranged on the second main face 34.
  • the secondary turning optic 14 is coupled to the first main face 35 via a layer 48 having a refractive index lower than the refractive index of the optical volume 37.
  • FIG 18 illustrates a cross-sectional view of the transparent optic of FIG 17, according to an embodiment. The example of FIG 18 depicts the first turning optic 13, the optical volume 37 and the secondary turning optic 14 coupled to the transparent optic 12 via the layer 48.
  • FIG 19 illustrates an optical system 10 according to another embodiment herein.
  • the first turning optic 13 comprises an array of geometrical structures 105 placed adjacent to each other running along a portion of the transparent optic 12.
  • Figure 19 illustrates the first turning optic 13, which is coupled to the transparent optic 12 via a wavelength selective filter.
  • an optical filter 753, such as a Bragg grating, is illustrated as the wavelength selective filter.
  • Light rays 104 incident on the optical filter 753 behave differently depending on the wavelength of light.
  • Bragg gratings can be inscribed such that light rays of a certain wavelength reflect off the Bragg grating at a certain angle such as rays 751 reflected as 752 while rays of other wavelengths transmit through the Bragg grating and reflect off the prismatic structures such as rays 104 reflected as 106 at a different angle.
  • Different Bragg gratings can be placed at different locations such as 753 and 754 sensitive to different wavelengths of light.
  • the light rays 39 and 40 from a light source assembly 11 enters the optical volume 37 via a redirecting optic 802.
  • the redirecting optic 802 may comprise reflective faces.
  • the redirecting optic 802 conditions the light to enter into the optical volume 37 at appropriate angles in such a manner so that the light exits the optical volume 37 to illuminate the scene 15.
  • An advantage of such an embodiment is that the light source assembly 11, the redirecting optic 802, the first turning optic 13 and the secondary turning optic 14 can be applied to an existing transparent optic 12 such as a glass window or table and render it as a display.
  • the light from a light source assembly 930 or projector enters an array of transparent optics that changes the throw angle of light in a locally concentrating manner or diverging manner.
  • the transparent optic 924 comprises a geometry to alter the angular throw of adjacent pixels 921,922 and 923 in such a manner that rays are transmitted by the optic and exit the optic 10 in a convergent manner into areas 925, 926 and 927 respectively.
  • Such an optic could be repeating in spatial arrangement.
  • One example of such an optic could be a micro -lens array.
  • An example application of the description could be a display capable of projecting a light field. In light field projection, the user is capable of viewing a multidimensional image depending on his location and orientation. In certain cases, the user can be made to view different images based on his position and viewpoint.
  • an optical system 10 is illustrated according to another embodiment herein.
  • light from the light source assembly 11 entering the optical volume 37 is incident onto a reflecting face 1202 of the transparent optic 12.
  • the reflecting face 1202 reflects the light onto the first turning optic 13 which provides the added turn for the light to exit the optical volume 37.
  • the light exiting the optical volume 37 is transmitted to the target, i.e., the scene 15 via the secondary turning optic 14.
  • the reflecting face 1202 may be curved laterally.
  • a propagation area 1402 of the transparent optic 12 is cut laterally to comprise a triangular profile. This provides the advantage of reduced material consumption and weight.
  • the term propagation area used herein is defined as a portion of the transparent optic 12 where the light rays propagate through internal reflection without undergoing a turn from the first turning optic.
  • the propagation area 1402 can be tilted out of the plane of the optical volume 37.
  • a portion 1404 of the transparent optic 12 comprising the first turning optic 13 may comprise a geometrical structure of a wedge.
  • the illumination of the target scene can be achieved using a similarly scaled optic located on the face 36 as depicted in FIG 26.
  • the illumination optic 1601 is placed in a manner to direct light from a source 1602 into the surface 36. This light exits the optical volume 37 via the first turning optic 13 onto the target.
  • This illumination pattern is optimized such that the resultant illumination from a uniformly reflecting target is uniform at the photosensor 11.
  • the illumination exiting out of 13 is a batwing profile.
  • the embodiments described herein provides the advantage of the optical system transmitting light from a source to a large area. Also, reduction in the distance between the target and the optical system is achieved. Conventional system, such as a lens does not provide the advantage of reduction in the distance. Also, the conventional systems have the disadvantage of being bulky.
  • the optical system described in the embodiments herein provides a compact and substantially flat configuration. Moreover, the optical system may be developed using a flat transparent optic, wherein the two main faces of the transparent optic are parallel. The first turning optic can be arranged on one of the main faces of the transparent optic. This provides the advantage of easy manufacturing of the optical system.
  • the optical system described in the embodiments herein can be used for 2D illumination.
  • the optical system described herein allows for a compact method of illumination in applications such as backlights for displays, for example, LCD displays.
  • An LCD screen placed in front of such an optical system can be used to modulate the light to deliver video content to users.
  • Multiple light sources can be placed at one face of the optical system to deliver light in various colors. Since light from each source is capable of spreading to a large area, colorimetric control is possible using only modulation of light intensities at the source to control the overall illumination spectrum.
  • Other example applications are automotive lighting and flood lighting for stadia and avenues.
  • Another application is in the field of clinical chemistry analysis and diagnostics. Samples arrive in containers or slides and are illuminated with light of certain wavelengths.
  • the device can provide a compact illumination source.
  • the device can provide for an extended illumination source for analyzing multiple samples at a single point in time.
  • the optical system may also be used for 2D displays.
  • a 2D display may be developed using a projector as the light source assembly. Large scale displays could be constructed. Examples of such displays are room sized immersive units where the optic is placed adjacent every wall and projects content to the user. For example, this can be used at establishments for advertising. Since the optic is compact and can scale in size, it has the potential to be ubiquitous. Examples of content delivery include shifting the video content as a user moves around in a space to enable him to continue viewing the same content regardless of position. Another example is in the space of displays for automotive. Such device can be clubbed to windscreens and windows to provide informative content.
  • the optical system may also be used for 3D displays. Using multiple projectors, stereo projection may be possible.
  • slits in front of the emission area allow for 3D emission of light. Multiplexing of spatial pixels is possible via slits or microlenses to provide for 3D or auto stereoscopic illumination.
  • the optical system may also be implemented for illuminating a curved surface. As the optical system need not be flat, the advantage of providing illumination to structures of different shapes is beneficial.
  • the optical system can be made to run parallel to an existing surface, such as a curved wall and display images or illuminate other objects.
  • Another example application is the use of such an optical system for illuminating plants. Algae have been known to clean water in the presence of illumination. In order to increase the density of algae in a purifier, the illumination system must be so designed that it is thin, flexible and can effectively transmit light to the algae.
  • the optical system described herein may be suited for such an application.
  • the optical system may be used for light coupling and mixing.
  • the primary optic or the propagation element is coupled to one or multiple light sources 522, 523, 524 in such a manner to emit light from a common region of the emission region 14.
  • the light sources could be tilted to position the rays to emerge out of a common region in the first turning optic 525.
  • the optical system may be used for generating collimated mixing light.
  • light mixing of several light sources is essential to provide a uniform and stable illumination in brightness and color rendering.
  • Several techniques are available for light mixing, however, collimated light emission is yet a challenge.
  • the optical system can quickly expand to be seen to emit from a large area at a short throw distance, light mixing is enabled in a collimated manner. The resultant light could be easily converged or diverged using additional optics.
  • the optical system may be used in luminaires.
  • the optical system can be made using thin and flexible material, it can be applied to a large surface as a luminaire.
  • a thin transparent optic that runs all along the ceiling of a room could provide light emerging from a large area.
  • the optical system may also be used for structured illumination.
  • the optical system could be used to project structured illumination wherein the illumination is a combination of structured bands of one or more colors.
  • the bands could be dark and bright alternatively either in a step -wise illumination pattern or a gradually varying sinusoidal pattern.
  • a projector or a set of masks could be used as the light source assembly and the optical system can be used for expansion and emission. Such an arrangement could produce higher contrast ratio of projection using simple masks and light sources. These masks could be phase shifted and projected to allow for high resolution structured light illumination and metrology.
  • the optical system may also be used for borescope illumination.
  • borescopes aim to illuminate the sides of the space they are inspecting such as a pipe.
  • the optical system can be used to illuminate large sections of the target since illumination can be easily expanded to a large region.
  • structured illumination is possible by the same principle.
  • the optical system may also be used as an user interface.
  • a combined display and imaging system could be used for dynamic projection of content. Based on users' gestures or touch movements, content could be altered.
  • the optical system may be used for frustrated total internal reflection.
  • the optical system 10 is appended with another optical slab 701 running along the primary emission area such that light can be trapped from a second light source assembly 711.
  • frustrated total internal reflection is allowed to occur and thus, enabling the device for multi-touch interactions.
  • Such an application can also be constructed using a hollow configuration and a film of geometric structures.
  • the optical system may be used for pulsed illumination.
  • the source of light can allow for pulsed illumination.
  • Such an adaptation is also instrumental for time of flight imaging.
  • the optical system may also be used for adaptive illumination.
  • the spatial and temporal distribution of intensity can be controlled via a secondary sensor placed elsewhere or adjunct with the primary light source in order to deliver content at higher contrast.
  • the optical system can also be used for transparent displays.
  • the optical system is capable of transmitting light from a projector or light source placed at the entry face.
  • light from the second main face could also enter the optical volume and exit from the first main face. This allows for viewing both the objects behind the optical device along with the light from the display. Text or graphical information could be used to highlight certain areas of the object behind the display or provide cues.
  • the optical system 10 is placed in front of the gage 301 to be read out (in remote monitoring or continuous monitoring scenarios) via image capture.
  • placing a camera will restrict the viewing of the gage by a human.
  • An elegant solution would be to have a transparent optic that redirects some of the light towards a camera 303 placed away from the line of sight of the gage and the viewer, thereby allowing for image capture as well as allowing a user 304 to view the gage.
  • the optical system 10 may be used for filtering and combining sources of different spectra as shown in FIG 30.
  • the optical system 10 is appended with several Bragg gratings 753, 754, of different wavelength transmission and reflection values.
  • Light sources of different spectra are fed at the input surface of the optical system 10 and are seen emitted at different locations depending on the wavelength. Multiple sources can be combined to increase the irradiation strength of the emitted light at different wavelengths hence providing higher signal to noise ratio for measurements.
  • Such arrangements are useful in spectral sensors such as air and water pollution sensor, sensors for clinical chemistry, etc.
  • a plurality of transparent optics can be arranged in series. As illustrated in FIG 31, light from a light source assembly 11 is fed into the transparent optic 12a which perturbs a part of the cone of rays towards the secondary optic 14 to illuminate a scene 15 whereas another part is directed towards another face to exit towards an additional transparent optic 12b and continues until it reaches the first turning optic 13 to be emitted out onto a second scene 28.
  • Such an arrangement allows for chaining several such primary optics using a lesser number of light sources.
  • One embodiment of the geometric structure is depicted as 601 in FIG 32. The structure is prismatic bounded by base face 604, the leading edge face 602 and the trailing edge face 603.
  • a ray 606 arising from the transparent optic volume 37 passes through the face 604 and is reflected by the face 602 to return as the ray 605.
  • the reflection by the face 602 imparts a turn in the rays. In essence, if the ray were to reflect off faces 34 or 35, such a turn would not be imparted.
  • Depicted in figure 32 is the geometric structure bound by faces 602, 603 and 604 or alternatively, bound by faces 602, 603 and 35.
  • the surface normal of the face 602 is shown as 610.
  • the angle of incidence 611 of the ray 606 and the angle of reflection 612 are the same as measured from the surface normal 610.
  • the angle 614 when measured from the surface normal 615 of the face 35, the angle 614 is different from the angle 613 subtended by the reflected ray 605 at the surface normal 609. This change in angle is facilitated by the geometric structure to condition the ray 606 to exit the optical volume 37 in a prescribed manner.
  • the angle 608 of the leading edge face is small in-order to impart a small turn in direction of the ray 606.
  • the angle 608 is less than 10 degrees.
  • the angle is less than 3 degrees.
  • the angles is less than 1 degree.
  • the ray 606 would require a larger number of reflections to be conditioned to exit the optical volume 37. In effect, the distance between the faces 34 and 35 can be reduced to enable a slimmer optical device for scanning.
  • the second angle of the prism 607 is less than a prescribed value. This avoids the collision of rays 605 and the face 603, thereby preventing loss of rays or spatial structure. Since the rays may undergo multiple interactions between the prismatic structures wherein each interaction results in an additional turn, the second angle 607 is chosen to prevent collision of the reflected ray and the prismatic face 603 at the respective prism.
  • Critical angle is defined as the angle of incidence above which total internal reflection occurs.
  • the second angle of the prism 607 is less than the difference of 90 degrees and critical. In a further embodiment, the second angle of the prism 607 is less than the difference 90 degrees and the sum of the critical angle and product of the number of reflections undergone by the ray 606 and twice the prism angle 608.
  • Depicted in figure 33 is the path of a ray entering from one extreme of the face 35. Once the ray enters, it undergoes one or more reflections within the optical volume 37. In the event of multiple reflections, the angle successively is altered and the distance between the point of reflection increases. The distance between the point of entry and the first reflection is Do , whereas the distance between the first and the second reflection is Di and so on. These distances are given by the following formulae.
  • N is the total number of reflections undergone by the ray under the influence of the turning optic.
  • the length of the area adapted to admit light L is the sum of the distances D0+D1+. . . +D Depicted in FIG 34, the propagation area length can be reduced by imparting a further turn by 710 to the rays exiting the area adapted to receive light. Increased reflections in the propagation area allow for a decreased propagation area length.
  • the opposing faces of the propagation areas could be silvered, thus preventing the light exiting the optical volume even beyond the critical angle.
  • the opposite faces of the propagation area may be coated with bragg gratings , photonic crystals or perfect mirrors to increase the efficiency of reflection.
  • FIG 35 illustrates illuminating a scene or an object from multiple angles using a monolithic piece of optic using one or more light sources. A portion of the light from the source exits the optical volume after interacting with the turning optic 13 while another portion exits the offshoot area 705 after interacting with the turning optic 700. Thus, lighting of the scene 15 is possible from two different directions. This configuration may be used to illuminate side views along with the front view of objects like food items for quality control.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Non-Portable Lighting Devices Or Systems Thereof (AREA)

Abstract

L'invention concerne un système optique, le système optique comprenant une optique transparente définissant un volume optique, l'optique transparente comprenant une première face principale adaptée pour émettre de la lumière et une première optique rotative destinée à faire tourner la lumière à l'intérieur du volume optique de sorte que la lumière sorte du volume optique après avoir atteint l'angle critique.
PCT/IB2014/064175 2013-09-01 2014-09-01 Dispositif optique destiné à transmettre et émettre de la lumière WO2015028992A1 (fr)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
IN3355/CHE/2013 2013-09-01
IN3353CH2013 2013-09-01
IN3353/CHE/2013 2013-09-01
IN3355CH2013 2013-09-01

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WO2015028992A1 true WO2015028992A1 (fr) 2015-03-05

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Publication number Priority date Publication date Assignee Title
WO2016171705A1 (fr) 2015-04-23 2016-10-27 Leia Inc. Rétroéclairage à base de réseau de diffraction à guide de lumière double et dispositif d'affichage électronique l'utilisant
US10810917B2 (en) 2015-03-30 2020-10-20 Leia Inc. 2D/3D mode-switchable electronic display with dual layer backlight

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WO2002097324A1 (fr) * 2001-06-01 2002-12-05 Lumileds Lighting U.S., Llc Systeme d'eclairage compact et dispositif d'affichage
EP1562065A1 (fr) * 2002-11-05 2005-08-10 Matsushita Electric Industrial Co., Ltd. Element d'affichage et dispositif d'affichage pourvu d'un tel element
JP2006065360A (ja) * 2005-11-16 2006-03-09 Omron Corp 導光器及び表示装置
US20090161368A1 (en) * 2007-12-19 2009-06-25 Edward Pakhchyan Display
EP2157460A1 (fr) * 2008-08-18 2010-02-24 Sony Corporation Appareil d'affichage d'images
US20120218778A1 (en) * 2011-02-28 2012-08-30 Kabushiki Kaisha Toshiba Display element and display device

Patent Citations (6)

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Publication number Priority date Publication date Assignee Title
WO2002097324A1 (fr) * 2001-06-01 2002-12-05 Lumileds Lighting U.S., Llc Systeme d'eclairage compact et dispositif d'affichage
EP1562065A1 (fr) * 2002-11-05 2005-08-10 Matsushita Electric Industrial Co., Ltd. Element d'affichage et dispositif d'affichage pourvu d'un tel element
JP2006065360A (ja) * 2005-11-16 2006-03-09 Omron Corp 導光器及び表示装置
US20090161368A1 (en) * 2007-12-19 2009-06-25 Edward Pakhchyan Display
EP2157460A1 (fr) * 2008-08-18 2010-02-24 Sony Corporation Appareil d'affichage d'images
US20120218778A1 (en) * 2011-02-28 2012-08-30 Kabushiki Kaisha Toshiba Display element and display device

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US10810917B2 (en) 2015-03-30 2020-10-20 Leia Inc. 2D/3D mode-switchable electronic display with dual layer backlight
WO2016171705A1 (fr) 2015-04-23 2016-10-27 Leia Inc. Rétroéclairage à base de réseau de diffraction à guide de lumière double et dispositif d'affichage électronique l'utilisant
EP3292432A4 (fr) * 2015-04-23 2018-12-05 LEIA Inc. Rétroéclairage à base de réseau de diffraction à guide de lumière double et dispositif d'affichage électronique l'utilisant
US10788619B2 (en) 2015-04-23 2020-09-29 Leia Inc. Dual light guide grating-based backlight and electronic display using same

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