Optical guide suitable for creating two luminous imprints

• US 9,575,317 B2
• Filed: 10/28/2014
• Issued: 02/21/2017
• Est. Priority Date: 10/29/2013
• Status: Active Grant

• Current Assignee: Optinvent SA
• Original Assignee: Optinvent SA
• Inventors: Sarayeddine, Khaled, Hugel, Xavier, Benoit, Pascal
• Primary Examiner(s): KIM, ELLEN E
• Application Number:
  US15/032,748
• Publication Number:
  US 20160306170A1
• Time in Patent Office: 847 Days
• Field of Search: 385/11, 385/146, 385/43, 385129-131, 349/61, 349/62, 349/65, 349/67
• US Class Current: 1/1
• CPC Class Codes: G02B 2027/0123 comprising devices increasing the field of view
• CPC Class Codes: G02B 2027/0125 Field-of-view increase by wavefront division
• CPC Class Codes: G02B 27/0101 characterised by optical features G02B27/0172 takes precedence
• CPC Class Codes: G02B 27/0172 characterised by optical features
• CPC Class Codes: G02B 27/0176 characterised by mechanical features
• CPC Class Codes: G02B 27/283 used for beam splitting or combining
• CPC Class Codes: G02B 5/30 Polarising elements light-modulating devices with active elements G02F1/00
• CPC Class Codes: G02B 5/3083 Birefringent or phase retarding elements G02B5/3008, G02B5/3016 take precedence; systems for polarisation control G02B27/286; manufacturing phase modulating patterns by lithographic processes G03F7/001
• CPC Class Codes: G02B 6/00 Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
• CPC Class Codes: G02B 6/0036 2-D arrangement of prisms, protrusions, indentations or roughened surfaces
• CPC Class Codes: G02B 6/005 provided by one optical element, or plurality thereof, placed on the light output side of the light guide
• CPC Class Codes: G02B 6/0056 for producing polarisation effects, e.g. by a surface with polarizing properties or by an additional polarizing elements

Abstract

An optical guide comprises at least one guiding element adapted for enabling, by total internal reflections, transporting an image taking the form of a collimated light beam from an injection zone to an extraction zone where an extracting device for extracting the image is mounted. The optical guide comprises a retardation plate and a polarization beam splitter, the polarization beam splitter being placed between the guiding element and the extracting device. The optical guide is such that each ray of said collimated light beam striking the polarization beam splitter for the first time separates into two portions, a first portion being transmitted to the extracting device so as to define a first light imprint and a second portion being reflected by the polarization beam splitter, said second portion continuing to be guided by the guiding element and thus passing twice through the retardation plate before striking the polarization beam splitter so as to define a second light imprint.

Claims

1. An optical guide comprising at least one guiding element adapted for enabling, by total internal reflections, transporting an image in the form of a collimated light beam from an injection zone to an extraction zone where an image extracting device is mounted, the optical guide comprising a retardation plate and a polarisation beam splitter, the polarisation beam splitter being placed between the guiding element and the extracting device, the optical guide being such that each ray of said collimated light beam striking the first polarisation beam splitter separates into two portions, a first portion being sent to the extracting device so as to define a first light imprint and a second portion being reflected by the polarisation beam splitter, said second portion continuing to be guided by the guiding element and thereby passing twice through the retardation plate before hitting the polarisation beam splitter so as to define a second light imprint,

wherein the optical guide comprises two guiding elements the retardation plate is sandwiched between the two guiding elements, and the polarisation beam splitter is sandwiched between an outer face of the assembly formed by said guiding elements and the extracting device.

2. The optical guide according to claim 1, wherein the extracting device consists of a plate, the outer face of which comprises a set of reflective microstructures formed on surface, said microstructures consisting of prisms having an angle enabling the collimated light beam to emerge from the optical guide.

3. The optical guide according to claim 1, wherein the extracting device consists of a first portion comprising a set of semi-reflective microstructures formed on surface, said microstructures consisting of prisms having an angle enabling the collimated light beam to emerge from the optical guide, and a second portion having on surface microstructures with a shape complementary to those of the first portion, an adhesive layer joining the first and second portions so that any microstructure of the first portion is separated from its complementary microstructure of the second portion by a transparent medium of substantially constant thickness.

4. Optical guide according to claim 1, wherein the optical guide comprises a mechanical reinforcement by compensating a difference between the thickness of the optical guide in a zone where the collimated light beam is propagated by total internal reflections and the thickness of the optical guide at the extraction zone, so that said mechanical reinforcement does not change said total internal reflections.

5. Optical guide according to claim 1, wherein the polarisation beam splitter is implemented by interferential treatment in the form of vacuum deposition of a plurality of layers of different materials with different indices, so that the transmissivity for the p-polarisation is total, the reflectivity for the p-polarisation is null, the transmissivity for the s-polarisation is partial and the reflectivity for the s-polarisation is also partial, or vice-versa.