CN116047647A - Device and method for expanding optical waveguide view field range - Google Patents
Device and method for expanding optical waveguide view field range Download PDFInfo
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- CN116047647A CN116047647A CN202211683079.3A CN202211683079A CN116047647A CN 116047647 A CN116047647 A CN 116047647A CN 202211683079 A CN202211683079 A CN 202211683079A CN 116047647 A CN116047647 A CN 116047647A
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- waveguide
- waveguide sheet
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- wedge
- field
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- 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
- G02B6/005—Means for improving the coupling-out of light from the light guide provided by one optical element, or plurality thereof, placed on the light output side of the light guide
- G02B6/0053—Prismatic sheet or layer; Brightness enhancement element, sheet or layer
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- 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
- G02B27/017—Head mounted
- G02B27/0172—Head mounted characterised by optical features
-
- 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
- G02B6/42—Coupling light guides with opto-electronic elements
-
- 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
- G02B2027/0123—Head-up displays characterised by optical features comprising devices increasing the field of view
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- General Physics & Mathematics (AREA)
- Optics & Photonics (AREA)
- Optical Integrated Circuits (AREA)
Abstract
The invention relates to a device and a method for expanding the visual field range of an optical waveguide, wherein the device comprises a waveguide sheet, a coupling-in prism, an array reflecting film and an optical wedge; the central ray of the incident light enters the waveguide sheet to become a central view field ray after passing through the coupling-in prism, and the array reflecting film is arranged in the waveguide sheet; the included angle between the array reflecting film and the total reflecting surface of the waveguide sheet is theta, and the included angle beta between the central view field light ray and the perpendicular line of the total reflecting surface of the waveguide sheet is more than 2 theta by changing the angle of the coupling-in prism; the optical wedge is arranged at the emergent total reflection surface of the waveguide sheet; the optical wedge is used for enabling light of the central view field to be perpendicular to the total reflection surface of the waveguide sheet when entering human eyes, and meets the viewing habit of the human eyes.
Description
Technical Field
The invention relates to the technical field of Augmented Reality (AR), in particular to a device and a method for expanding the field of view of an optical waveguide.
Background
The following is merely representative of the background art which the inventors have grasped and is not prior art which is readily available to the public.
In the AR field, the angle of view is an important parameter affecting the effect of AR spectacles. For the current optical waveguide module, in order to enable the central view field of the optical machine to enter the human eye after passing through the waveguide sheet to be the central view field, the included angle between the incident central view field light and the perpendicular line of the total reflection surface of the waveguide sheet is equal to 2 times of the included angle between the reflection surface of the waveguide sheet array and the total reflection surface, so that the central view field of the optical machine is vertically emergent after passing through the waveguide sheet. Thus, the angle range that the waveguide sheet can be applied to is determined by the total reflection condition of the waveguide sheet, and is limited to a certain range.
As shown in fig. 1, the angle (2θ) between the central field of view of the incident light 4 (central field of view ray) and the perpendicular to the total reflection surface of the waveguide sheet in the waveguide sheet 1 is 2 times the angle (θ) between the array reflection film 3 in the waveguide sheet and the total reflection surfaces (5, 6) of the waveguide sheet; at this time, the direction of the central view field light rays emitted out of the waveguide sheet is perpendicular to the total reflection surface of the waveguide sheet. When θ is fixed, it is assumed that the refractive index of the waveguide plate is n 1 The total reflection condition is limited, the angle range of the incident light in the waveguide sheet is F 1 ＝2*[2θ-arcsin(1/n 1 )]. In fig. 1, reference numeral 2 denotes an incoupling prism.
Disclosure of Invention
The invention aims to provide a device and a method for expanding the view field range of an optical waveguide, which aims to solve the technical problem of expanding the view field range of an AR optical module, and simultaneously ensure that the emergent ray of a central view field is vertical to the total reflection surface of the waveguide sheet, so as to accord with the viewing habit of human eyes.
The invention aims to solve the defects in the prior art and provides a device for expanding the field of view of an optical waveguide, which comprises a waveguide sheet, a coupling-in prism, an array reflecting film and an optical wedge; the incident light central line enters the waveguide sheet to become central view field light after passing through the coupling-in prism, and the array reflecting film is arranged in the waveguide sheet; the included angle between the array reflecting film and the total reflecting surface of the waveguide sheet is theta, and the included angle beta between the central view field light ray and the perpendicular line of the total reflecting surface of the waveguide sheet is more than 2 theta by changing the angle of the coupling-in prism; the optical wedge is arranged at the emergent total reflection surface of the waveguide sheet; the optical wedge is used for enabling light of the central view field to be perpendicular to the total reflection surface of the waveguide sheet when entering human eyes, and meets the viewing habit of the human eyes.
Preferably, the refractive index of the waveguide sheet is assumed to be n 1 The angle range of the incident light meeting the total reflection condition in the waveguide sheet is F 2 ＝2*[β-arcsin(1/n 1 )]。
Preferably, a predetermined gap is left between the optical wedge and the waveguide sheet, so as to ensure the total reflection condition of the waveguide sheet.
Preferably, the total length of the array reflection film of the waveguide sheet is assumed to be L 1 The optical wedge has a length greater than L 2 And the optical wedge covers L 1 Length range of (2); wherein L is 2 ＞L 1 。
Further preferably, the wedge angle of the optical wedge is noted as phi, assuming the refractive index of the optical wedge is n 2 Phi= (n) 2 -1)*arcsin[n 1 *sin(2β-4θ)]。
Further preferably, it is assumed that the minimum thickness of the optical wedge is h 1 When the maximum thickness of the optical wedge is h=h 1 +L 2 *tanφ。
The invention also provides a method for expanding the field of view of the optical waveguide, which comprises the following steps:
the first step, changing the angle of the coupling-in prism to enable the included angle beta between the central view field light and the perpendicular line of the total reflection surface of the waveguide sheet to be more than 2 theta; when the included angle theta between the array reflective film and the total reflective surface of the waveguide sheet is fixed, the refractive index of the waveguide sheet is assumed to be n 1 The angle range of the incident light meeting the total reflection condition in the waveguide sheet is F 2 ＝2*[β-arcsin(1/n 1 )]The method comprises the steps of carrying out a first treatment on the surface of the The angle of view of the waveguide sheet is increased;
step two, adding an optical wedge at the emergent total reflection surface of the waveguide sheet; the optical wedge is used for enabling light of the central view field to be perpendicular to the total reflection surface of the waveguide sheet when entering human eyes, and meets the viewing habit of the human eyes.
Advantageous effects
Compared with the prior art, the invention has the beneficial effects that:
the device and the method for expanding the field of view of the optical waveguide adopt a mode that the included angle between the incident central field of view light in the waveguide sheet and the perpendicular line of the total reflection surface of the waveguide sheet is 2 times larger than the included angle between the reflection surface of the waveguide sheet array and the total reflection surface, and at the moment, the field of view center shifts to the direction of increasing the incident angle in the waveguide sheet, so that the angle of the field of view transmitted in the waveguide sheet is increased, and the field of view range of the AR optical module is expanded; an optical wedge is added outside the waveguide sheet, so that outgoing light rays of the central view field are vertical to the total reflection surface of the waveguide sheet, and viewing habit of human eyes is met.
Drawings
The accompanying drawings are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate and do not limit the invention.
Fig. 1 is a schematic diagram of a general arrangement of a waveguide sheet in the background art.
Fig. 2 is a schematic structural view of an apparatus for expanding the field of view of an optical waveguide according to the present invention.
Detailed Description
The present invention is described in more detail below to facilitate an understanding of the present invention.
As shown in fig. 2, the device for expanding the field of view of the optical waveguide according to the present invention comprises a waveguide sheet 1, an in-coupling prism 2, an array reflective film 3 and an optical wedge 7; the incident light enters the waveguide sheet 1 after passing through the coupling-in prism 2 to become central view field light 4, and the array reflection film 3 is arranged inside the waveguide sheet 1; the included angle between the array reflecting film 3 and the total reflecting surface of the waveguide sheet 1 is theta, and the included angle beta between the central view field light 4 in the waveguide sheet and the perpendicular line of the total reflecting surface of the waveguide sheet is more than 2 theta by changing the angle of the coupling-in prism.
Thus, when θ is fixed, the folding of the waveguide sheet is assumedEmissivity of n 1 The angle range of the incident light meeting the total reflection condition in the waveguide sheet is F 2 ＝2*[β-arcsin(1/n 1 )]＝F 1 +2(β-2θ)>F 1 The method comprises the steps of carrying out a first treatment on the surface of the Obviously, the angle of view of the waveguide sheet increases.
By adopting the mode, when the light of the central view field exits the waveguide sheet, the light is not perpendicular to the total reflection surface of the waveguide sheet, and the viewing habit of human eyes is not met; therefore, an optical wedge 7 is added at the position of the total reflection surface 5 of the emergent waveguide sheet; let the total length of the array reflection film 3 of the waveguide plate be L 1 The wedge length should be greater than L 2 And is covered with L 1 Length range of (2); in addition, a certain gap is reserved between the optical wedge and the waveguide sheet (in order to make the structure as compact as possible, the actual gap reference quantity is between 0 and 0.3 mm), so that the total reflection condition of the waveguide sheet is ensured; the wedge angle of the wedge is noted as phi, assuming the index of refraction of the wedge is n 2 Phi= (n) 2 -1)*arcsin[n 1 *sin(2β-4θ)]The method comprises the steps of carrying out a first treatment on the surface of the Based on the consideration of the processing technology, the minimum thickness of the optical wedge is assumed to be h 1 When the maximum thickness of the optical wedge is h=h 1 +L 2 * tan phi. Thus, after passing through the optical wedge, the light of the central field of view is vertical to the total reflection surface of the waveguide plate when entering human eyes, and accords with the viewing habit of human eyes.
In practical operation, in order to ensure the portability of the product, L 2 In the guarantee of being able to cover L 1 In the case of the length of (2), as small as possible, reference can be made to L 1 And L 2 Is coincident with 0<L 2 -L 1 <2mm。
The invention also provides a method for expanding the field of view of the optical waveguide, which comprises the following steps:
the first step, changing the angle of the coupling-in prism to enable the included angle beta between the central view field light 4 and the vertical line of the total reflection surface of the waveguide sheet in the waveguide sheet to be more than 2 theta; when the angle θ between the array reflective film 3 and the total reflection surface of the waveguide sheet 1 is fixed, the refractive index of the waveguide sheet is assumed to be n 1 The angle range of the incident light meeting the total reflection condition in the waveguide sheet is F 2 ＝2*[β-arcsin(1/n 1 )]The method comprises the steps of carrying out a first treatment on the surface of the Waveguide sheetIs increased;
step two, an optical wedge 7 is added at the emergent total reflection surface 5 of the waveguide sheet; the optical wedge is used for enabling light of the central view field to be perpendicular to the total reflection surface of the waveguide sheet when entering human eyes, and meets the viewing habit of the human eyes.
The device and the method for expanding the field of view of the optical waveguide adopt a mode that the included angle between the incident central field light and the perpendicular line of the total reflection surface of the waveguide sheet is larger than the included angle between the reflection surface of the waveguide sheet array and the total reflection surface by 2 times, shift the field center to the direction of increasing the incident angle in the waveguide sheet, and further increase the field angle transmitted in the waveguide sheet, thereby expanding the field range of the AR optical module. An optical wedge is added outside the waveguide sheet, so that outgoing light rays of the central view field are vertical to the total reflection surface of the waveguide sheet, and viewing habit of human eyes is met.
The foregoing describes preferred embodiments of the present invention, but is not intended to limit the invention thereto. Modifications and variations to the embodiments disclosed herein may be made by those skilled in the art without departing from the scope and spirit of the invention.
Claims (10)
1. The device for expanding the view field range of the optical waveguide is characterized by comprising a waveguide sheet, a coupling-in prism, an array reflecting film and an optical wedge; the central ray of the incident light enters the waveguide sheet to become a central view field ray after passing through the coupling-in prism, and the array reflecting film is arranged in the waveguide sheet; the included angle between the array reflecting film and the total reflecting surface of the waveguide sheet is theta, and the included angle beta between the central view field light ray and the perpendicular line of the total reflecting surface of the waveguide sheet is more than 2 theta by changing the angle of the coupling-in prism; the optical wedge is arranged at the emergent total reflection surface of the waveguide sheet; the optical wedge is used for enabling light of the central view field to be perpendicular to the total reflection surface of the waveguide sheet when entering human eyes, and meets the viewing habit of the human eyes.
2. The apparatus for extending the field of view of an optical waveguide of claim 1, whereinAssuming that the refractive index of the waveguide plate is n 1 The angle range of the incident light meeting the total reflection condition in the waveguide sheet is F 2 ＝2*[β-arcsin(1/n 1 )]。
3. The apparatus of claim 1, wherein a predetermined gap is provided between said wedge and said waveguide plate for ensuring total reflection of said waveguide plate.
4. The device for enlarging a field of view of an optical waveguide according to claim 1, wherein an overall length of an array reflection film of said waveguide sheet is assumed to be L 1 The optical wedge has a length greater than L 2 And the optical wedge covers L 1 Length range of (2); wherein L is 2 ＞L 1 。
5. The device for expanding the field of view of an optical waveguide of claim 1, wherein the wedge angle of the wedge is denoted as Φ, and the refractive index of the wedge is assumed to be n 2 Phi= (n) 2 -1)*arcsin[n 1 *sin(2β-4θ)]。
6. The device for extending the field of view of an optical waveguide of claim 4, wherein the minimum thickness of said wedge is assumed to be h 1 When the maximum thickness of the optical wedge is h=h 1 +L 2 *tanφ。
7. A method of expanding the field of view of an optical waveguide using the apparatus for expanding the field of view of an optical waveguide according to any one of claims 1 to 6, the method comprising the steps of:
the first step, changing the angle of the coupling-in prism to enable the included angle beta between the central view field light and the perpendicular line of the total reflection surface of the waveguide sheet to be more than 2 theta; when the included angle theta between the array reflective film and the total reflective surface of the waveguide sheet is fixed, the refractive index of the waveguide sheet is assumed to be n 1 The angle range of the incident light meeting the total reflection condition in the waveguide sheet is F 2 ＝2*[β-arcsin(1/n 1 )]The method comprises the steps of carrying out a first treatment on the surface of the The angle of view of the waveguide sheet is increased;
step two, adding an optical wedge at the emergent total reflection surface of the waveguide sheet; the optical wedge is used for enabling light of the central view field to be perpendicular to the total reflection surface of the waveguide sheet when entering human eyes, and meets the viewing habit of the human eyes.
8. The method of claim 7, wherein a predetermined gap is provided between the wedge and the waveguide sheet for ensuring total reflection of the waveguide sheet.
9. The method of enlarging a field of view of an optical waveguide as set forth in claim 7, wherein an overall length of an array reflective film of said waveguide sheet is assumed to be L 1 The optical wedge has a length greater than L 2 And the optical wedge covers L 1 Length range of (2); wherein L is 2 ＞L 1 。
10. The method of extending the field of view of an optical waveguide of claim 9, wherein the wedge angle of the optical wedge is denoted as Φ, and the refractive index of the optical wedge is assumed to be n 2 Phi= (n) 2 -1)*arcsin[n 1 *sin(2β-4θ)]The method comprises the steps of carrying out a first treatment on the surface of the Assuming that the minimum thickness of the optical wedge is h 1 When the maximum thickness of the optical wedge is h=h 1 +L 2 *tanφ。
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211683079.3A CN116047647A (en) | 2022-12-27 | 2022-12-27 | Device and method for expanding optical waveguide view field range |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211683079.3A CN116047647A (en) | 2022-12-27 | 2022-12-27 | Device and method for expanding optical waveguide view field range |
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| Publication Number | Publication Date |
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| CN116047647A true CN116047647A (en) | 2023-05-02 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN202211683079.3A Pending CN116047647A (en) | 2022-12-27 | 2022-12-27 | Device and method for expanding optical waveguide view field range |
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| CN (1) | CN116047647A (en) |
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- 2022-12-27 CN CN202211683079.3A patent/CN116047647A/en active Pending
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