WO2018195983A1

WO2018195983A1 - Optical waveguide structure and optical system

Info

Publication number: WO2018195983A1
Application number: PCT/CN2017/082576
Authority: WO
Inventors: 李国洲
Original assignee: 深圳市柔宇科技有限公司
Priority date: 2017-04-28
Filing date: 2017-04-28
Publication date: 2018-11-01
Also published as: CN108521794B; CN108521794A

Abstract

An optical waveguide (301), comprising at least one first base (11) and an expansion waveguide (20). The first base (11) is connected to the expansion waveguide (20); the expansion waveguide (20) comprises multiple semitransparent films (a, b, c, d, e) that are parallel to each other and obliquely embedded in a substrate (22); at least one of the left and right sides of the optical waveguide (301) is provided with a light absorbing material; incident light (L1, T1) enters the expansion waveguide (20) and then multiple light rays (L2, L3, L4, L5, L6, T2, T3, T4, T5, T6) parallel to each other exit; after the incident light (L1, T1) enters the expansion waveguide (20) and is reflected by at least one semitransparent film (a, b, c, d, e), the reflected light enters the first base (11) and then is totally reflected by the first base (11) and propagated to the side of the optical waveguide (301) that is provided with the light absorbing material; or after the incident light (L1, T1) enters the expansion waveguide (20) and is reflected by at least one semitransparent film (a, b, c, d, e), the reflected light is propagated by the first base (11) to the side of the optical waveguide (301) that is provided with the light absorbing material. An optical system comprising the optical waveguide (301) can reduce ghost images, thereby improving imaging quality.

Description

Optical waveguide structure and optical system

Technical field

The present invention relates to the field of optical waveguides, and more particularly to an optical waveguide structure and an optical system.

Background technique

Head-Mounted Display (HMD) has been widely used in military, industrial, medical and other fields for its immersion, interactivity and improved perception of potential. With the maturity of microdisplay technology, optical processing technology and optical design theory, HMD is moving towards miniaturization.

In view of the special requirements of head wear, existing transmissive HMDs typically employ a combination of a folded-back relay structure and an off-axis reflective combination mirror. Although the reentry relay structure allows the HMD to achieve large exits, the use of off-axis reflective combination mirrors greatly increases the difficulty of system off-axis aberration correction. It can be seen that the combination of the combination mirror and the relay system seriously increases the size and weight of the system. In order to solve the above problem, an optical waveguide technique in an HMD has been proposed. The optical waveguide technology eliminates the complicated optical system in the traditional HMD, and uses the waveguide to complete the image transmission and expansion, which greatly reduces the size and weight of the HMD while obtaining a large exit.

At present, waveguide technologies for HMD mainly include holographic waveguides and semi-transmissive film array waveguides. Holographic waveguides use holographic technology and optical waveguide concepts to achieve display, but the system light energy utilization is low, holographic grating preparation is difficult, and the stray light and dispersion introduced by diffraction seriously hinder its development. The semi-permeable membrane array waveguide realizes the display by the principle of geometric optical folding and reflection. The dispersion is small and easy to realize color display. Therefore, the design and preparation requirements are much lower than the holographic waveguide display, but the ghost image caused by the traditional semi-permeable membrane array waveguide is serious. Affects image quality. Therefore, the development of a semi-permeable membrane array waveguide capable of mitigating or even eliminating ghost images is a technical problem to be solved.

Summary of the invention

It is an object of the present invention to provide an optical waveguide structure and an optical system to reduce ghost images and thereby improve image quality.

In a first aspect, an embodiment of the present invention provides an optical waveguide structure, where the optical waveguide includes at least one a first substrate and an extension waveguide, the first substrate and the extension waveguide are connected, the extension waveguide includes a plurality of semi-transmissive films embedded in a substrate obliquely parallel to each other, at least one of left and right sides of the optical waveguide a light absorbing material is disposed on one side;

Wherein, after the incident light enters the extended waveguide, a plurality of mutually parallel outgoing rays are emitted; and when the incident light enters the extended waveguide and the reflected light reflected by the at least one semipermeable film enters the first substrate, the first Basement total reflection propagates to a side of the optical waveguide on which the light absorbing material is disposed, or that reflected light that is incident on the extended waveguide through the at least one semipermeable membrane propagates through the first substrate to the light The waveguide is provided with a side surface of the light absorbing material.

In a second aspect, an embodiment of the present invention provides an optical system including a display, an eyepiece system, and the optical waveguide of the first aspect, the eyepiece system being disposed between the display and the optical waveguide, the eyepiece system The optical axis is perpendicular to the display;

The divergent light of the line field of view of the display passes through the eyepiece system and becomes parallel light of angular field distribution, and the parallel light of each field of view passes through the optical waveguide and then expands out of the array, when the eyes are blind The display information displayed on the display can be obtained by coincident with the exit pupil plane of the optical system.

In the present solution, when the incident light enters the substrate through the at least one semi-permeable film, the reflected light enters the substrate, and then propagates through the substrate to the side of the optical waveguide provided with the light absorbing material, or when the incident light enters the expansion. The reflected light reflected by the waveguide through the at least one semi-permeable membrane propagates through the substrate to the side of the optical waveguide provided with the light absorbing material, and the light of the portion is absorbed on the side of the optical waveguide to prevent the portion of the light from being reflected through the side of the optical waveguide. Expanding the waveguide, thereby reducing ghosting and improving image quality.

These and other aspects of the invention will be more apparent from the following description of the embodiments.

DRAWINGS

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the embodiments or the description of the prior art will be briefly described below. Obviously, the drawings in the following description are only It is a certain embodiment of the present invention, and other drawings can be obtained from those skilled in the art without any creative work.

1 is a schematic diagram of an optical waveguide structure according to an embodiment of the present invention;

2 is a schematic diagram of light propagation based on the structure shown in FIG. 1 according to an embodiment of the present invention;

FIG. 3 is a schematic diagram of another light propagation based on the structure shown in FIG. 1 according to an embodiment of the present invention; FIG.

4(1) is a schematic diagram of another optical waveguide structure according to an embodiment of the present invention;

4(2) is a schematic diagram of another optical waveguide structure according to an embodiment of the present invention;

FIG. 5(1) is a schematic diagram of light propagation based on the structure shown in FIG. 4(1) according to an embodiment of the present invention; FIG.

FIG. 5(2) is a schematic diagram of light propagation based on the structure shown in FIG. 4 (2) according to an embodiment of the present invention; FIG.

FIG. 6 is a schematic diagram of an optical system according to an embodiment of the present invention; FIG.

FIG. 7 is a schematic diagram of another optical system according to an embodiment of the present invention.

detailed description

The technical solutions in the embodiments of the present invention are clearly and completely described in the following with reference to the accompanying drawings in the embodiments of the present invention. It is an embodiment of the invention, but not all of the embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative efforts shall fall within the scope of the present invention.

The details are described below separately.

The terms "first", "second", "third", and "fourth" and the like in the specification and claims of the present invention are used to distinguish different objects, and are not intended to describe a specific order. .

Referring to FIG. 1, FIG. 1 is a schematic diagram of an optical waveguide structure according to an embodiment of the present invention. The optical waveguide includes at least one first substrate 11, at least one second substrate 12, and an extended waveguide 20, and the first substrate 11, the expanded waveguide 20, and the second substrate 12 are stacked, and the expanded waveguide 20 includes a plurality of mutually obliquely embedded in the substrate The semipermeable membrane 21 of 22, at least one of the left or right side faces of the optical waveguide is provided with a light absorbing material, wherein the light absorbing material is, for example, chromium, silicon or the like.

Wherein, when only one side of the optical waveguide is provided with the light absorbing material, the side surface on which the light absorbing material is disposed is related to the position where the light spot is located. For example, as shown in FIG. 1, when the spot is placed above the right surface of the optical waveguide, the side surface on which the light absorbing material is disposed is the left side surface of the optical waveguide, and when the light spot is placed above the left surface of the optical waveguide, the light absorbing material is disposed. The side of the side is the left side of the optical waveguide.

Wherein, as shown in FIG. 2, the incident light enters the expanded T ₁ after the exit of the waveguide 20 a plurality of parallel light rays exiting (in a _{_{2 T 2, T 3, T}} 4, T 5 and T ₆ in FIG.), When the incident light The reflected light of T ₁ entering the extended waveguide 20 and reflected by the at least one semi-permeable membrane (such as the semi-permeable membrane a and the semi-permeable membrane b in FIG. 2 ) is propagated through the first substrate 11 to the side of the optical waveguide provided with the light-absorbing material (eg The left side of the optical waveguide in Figure 2);

And 3, the incident light L _{enters. 1} after expansion of the waveguide exit 20 of light exiting the plurality of parallel (L ₂ in FIG. _{_{3, L 3, L 4,}} L 5 , and _{L. 6),} when the incident light L ₁ after the reflected light reflected into the extended waveguide 20 through at least one semipermeable membrane (such as the semipermeable membrane c in FIG. 3) enters the second substrate 12, is totally reflected by the second substrate 12 and propagated to the optical waveguide and provided with the light absorbing material. Side (as shown on the right side of the optical waveguide in Figure 3).

Referring to FIG. 4, FIG. 4 is a schematic diagram of another optical waveguide structure according to an embodiment of the present invention. The optical waveguide includes at least one first substrate 11 and an extension waveguide 20, and the first substrate 11 and the extension waveguide 20 are connected (as shown in FIG. 4(1), the lower surface of the first substrate 11 is in contact with the upper surface of the extension waveguide 20, or As shown in FIG. 4 (2), the upper surface of the substrate 11 is in contact with the lower surface of the expanded waveguide 20, and the expanded waveguide 20 includes a plurality of semi-transmissive films 21 embedded in the substrate 22 obliquely obliquely to each other, and the left and right sides of the optical waveguide. At least one side of the medium is provided with a light absorbing material.

Wherein, as shown in Figure 5, the incident light into the T-extended 20 exit the waveguide a plurality of parallel light rays exiting ₁ (FIG. 5 (1) _{_{_{T 2, T 3, T 4}}} , T 5 and _{T. 6),} When the incident light T ₁ enters the extended waveguide 20 and is reflected by the at least one semipermeable membrane (such as the semipermeable membrane a and the semipermeable membrane b in FIG. 5 (1)) into the first substrate 11, the first substrate 11 is passed through the first substrate 11 The total reflection propagates to the side of the optical waveguide provided with the light absorbing material (as shown in the left side of the optical waveguide in Fig. 5(1)).

Or the incident light L ₁ enters the extended waveguide 20 and emits a plurality of mutually parallel outgoing rays (such as L ₂ , L ₃ , L ₄ , L ₅ and L _{6 in} FIG. 5 ( 2 )), when the incident light L ₁ enters the expansion. The reflected light reflected by the waveguide 20 through at least one semipermeable membrane (such as the semipermeable membrane c in FIG. 5 (2)) enters the first substrate 11 and passes through at least one substrate (such as the substrate 11 in FIG. 5 (2)). The reflection propagates to the side of the optical waveguide provided with the light absorbing material (as shown in the left side of the optical waveguide in Fig. 5 (2)).

It should be noted that FIGS. 1 to 5 are merely examples, and the present invention does not limit the number of the first substrate and the number of the second substrate.

It can be seen that when the optical waveguide includes only the first substrate and the extended waveguide, the first substrate and the extended waveguide are connected, and only when one side of the left and right sides of the optical waveguide is provided with the light absorbing material, when the incident light enters the extended waveguide through at least one half After the reflected light reflected by the transparent film enters the substrate, it is totally reflected by the substrate and propagates to the side of the optical waveguide provided with the light absorbing material, or when the incident light enters the extended waveguide and is reflected by at least one semipermeable film. The light is transmitted through the substrate to the side of the optical waveguide provided with the light absorbing material, and the light of the portion is absorbed on the side of the optical waveguide to prevent the portion of the light from being reflected into the extended waveguide through the side of the optical waveguide, thereby reducing ghosting. Improved image quality.

In addition, when the optical waveguide includes the first substrate 11, the extension waveguide 20, and the second substrate 12, the first substrate 11, the extension waveguide 20, and the second substrate 12 are stacked, and when light absorbing materials are disposed on both left and right sides of the optical waveguide, After the incident light enters the first substrate or the second substrate through the reflected light reflected by the at least one semi-permeable film, the first substrate or the second substrate is totally reflected and propagated to the left side or the right side of the optical waveguide, or When the incident light enters the extension waveguide and the reflected light reflected by the at least one semi-transmissive film propagates through the first substrate or the second substrate to the left side or the right side of the optical waveguide, the light absorption of the portion is absorbed on the side of the optical waveguide. In order to prevent this part of the light from being reflected into the extended waveguide through the side of the optical waveguide, thereby eliminating ghosting and improving the image quality.

In an example, the spacing of adjacent semipermeable membranes in the extended waveguide satisfies: 1) the normally exiting light does not reflect to the upper surface of the semipermeable membrane during propagation of the extended waveguide; 2) the optical disc is in the expanded beam array (ie, incident) The image is not lost when the light enters the different positions of the plurality of parallel outgoing rays that exit the extended waveguide 20. Therefore, the optical waveguide needs to satisfy the following first condition:

h ₁ ×tanα≤d ₁ <<d ₂

Wherein h ₁ is the thickness of the extended waveguide 20, the α is the first angle of view, the d ₁ is the spacing of any two adjacent semipermeable membranes, and the d _{2 is the} pupil size of the human eye.

Wherein, the first field of view is the maximum field of view of the left or right field of the human eye. For example, when the human eye looks straight ahead, the first field of view angle is 0, and the maximum field of view of the left field of the human eye is equal to the maximum field of view of the right field of the human eye, but the direction is different, assuming the maximum field of view of the human eye. At 60°, the first field of view is equal to ±30°.

In one example, the plurality of semipermeable membranes comprise a first semipermeable membrane and a second semipermeable membrane, the first semipermeable membrane being adjacent to a side of the optical waveguide adjacent to the incident light spot, the second semipermeable membrane a side of the film from the optical waveguide adjacent to the incident light spot is larger than a side of the first semi-permeable film from the optical waveguide adjacent to the incident light spot, and the first semi-permeable membrane is adjacent to the second semi-permeable membrane; The distance between the first semi-permeable membrane and the second semi-permeable membrane is a first spacing, and the first spacing is greater than the size of the incident spot.

For example, as shown in FIG. 2, if the side of the optical waveguide adjacent to the incident spot is the right side of the optical waveguide, the first semi-permeable membrane is a semi-permeable membrane c, and the second semi-permeable membrane is a semi-permeable membrane a, A pitch is the pitch of the semipermeable membrane c and the semipermeable membrane a. If, on the other hand, the side of the optical waveguide adjacent to the incident spot is the left side of the optical waveguide, then The semipermeable membrane is a semipermeable membrane e, and the second semipermeable membrane is a semipermeable membrane d. The first spacing is the spacing between the semipermeable membrane e and the semipermeable membrane d.

The semi-permeable membrane spacing is proportional to the spacing of the expanded beam array (ie, the plurality of parallel outgoing rays exiting the incident light into the extended waveguide 20), and the smaller the semi-permeable membrane spacing, the better the formation of a uniform pupil. However, the spacing should not be too small, especially the first spacing. When the first spacing is smaller than the size of the incident spot, some light will be incident from the upper half of the second semipermeable membrane and then extended toward the second semipermeable membrane. The upper surface of the waveguide, which in turn forms a ghost image, so the present invention sets the first pitch to be larger than the size of the incident spot, thereby further reducing the ghost image.

Further, the plurality of semipermeable membranes further comprise a plurality of third semipermeable membranes, at least one of the third semipermeable membranes being adjacent to the second semipermeable membrane.

Further, a distance between the second semipermeable membrane and the adjacent third semipermeable membrane is a second pitch, a spacing between any two adjacent third semipermeable membranes and the second The spacing is equal.

For example, as shown in FIG. 2, the first semipermeable membrane is c, the second semipermeable membrane is a, and the third semipermeable membrane is: semipermeable membrane b, semipermeable membrane d and semipermeable membrane e, semipermeable. The membrane a and the semipermeable membrane b are adjacent to each other, and the distance between the semipermeable membrane a and the semipermeable membrane b is the second spacing, and then the spacing between the semipermeable membrane b and the semipermeable membrane d is equal to the second spacing, the semipermeable membrane d and the semipermeable membrane The pitch of the film e is equal to the second pitch.

Further, the distance between the second semipermeable membrane and the adjacent third semipermeable membrane and the spacing between any two adjacent third semipermeable membranes are both a third pitch, The three pitches are sequentially decreased along the direction of the first semipermeable membrane toward the second semipermeable membrane.

For example, as shown in FIG. 1 , the first semi-permeable membrane is a semi-permeable membrane c, the second semi-permeable membrane is a semi-permeable membrane b, and the third spacing is: the distance between the semi-permeable membrane a and the semi-permeable membrane b is The distance between the semi-permeable membrane b and the semi-permeable membrane d is the third pitch 2, the distance between the semi-permeable membrane d and the semi-permeable membrane e is the third spacing 3, and the third spacing 2 is smaller than the third spacing 1 and the third spacing The pitch 3 is smaller than the third pitch 2, and the difference between the third pitch 1 and the third pitch 2 is equal to the difference between the third pitch 2 and the third pitch 3.

In an example, the optical waveguide satisfies the following second condition:

2S ≤ h ₂ × tanα

Wherein S is the length of the optical waveguide, and h ₂ is the thickness of the substrate (such as the substrate 11 and the substrate 12 in FIG. 1), and the α is the first angle of view.

In an example, the refractive indices of the plurality of semipermeable membranes are graded such that incident light enters the expansion The light energy of a plurality of mutually parallel outgoing rays emitted after the waveguide is the same.

For example, as shown in FIG. 2, there are five semipermeable membranes, and T ₁ is totally reflected into the semipermeable membrane a upon entering the semipermeable membrane c, and reflects 1/6 of the light on the semipermeable membrane a. 5/6 of the light enters the semipermeable membrane b, and (5/6)*(1/5) light is reflected on the semipermeable membrane b, and (5/6)*(4/5) light enters the semipermeable membrane d , (5/6)*(1/5)*(1/4) light is reflected on the semi-permeable membrane d, and (5/6)*(4/5)*(3/4) light enters the semi-transparent Membrane e, reflecting (5/6)*(1/5)*(1/4)*(1/3) of light on the semipermeable membrane e, (5/6)*(1/5)*(1 /4)*(2/3) is directly incident on the left side of the optical waveguide. It can be seen that the light energy of a plurality of mutually parallel outgoing rays that are emitted after the incident light enters the extended waveguide 20 is 1/6 of the incident light energy.

In an example, assuming that the optical waveguide is the structure shown in FIG. 1, the first substrate 11 and the second substrate 12 have the same thickness.

Further, the materials of the first substrate 11, the second substrate 12, and the substrate 22 are the same.

Further, the materials of the first substrate 11, the second substrate 12, and the substrate 22 are all high refractive index materials. High refractive index materials such as ZF7 facilitate compression spot size.

In an example, the angle between each of the semipermeable membranes 21 and the lower surface of the substrate 22 is in the range of 30 to 60.

In an example, the upper and lower surfaces of the optical waveguide are plated with an anti-reflection film. For example, assuming that the optical waveguide structure is the structure shown in FIG. 1, the surface on which the antireflection film is plated is the upper surface of the substrate 11 and the lower surface of the substrate 12.

It should be noted that the structure of the optical waveguide shown in FIG. 1 is a horizontally extending waveguide. Of course, the optical waveguide structure that satisfies the above technical features may also be a vertically extended waveguide.

Referring to FIG. 6, FIG. 6 is a schematic diagram of an optical system according to an embodiment of the present invention. The display 100, the eyepiece system 200 and the optical waveguide 301 (see FIG. 1 to FIG. 5 of the optical waveguide 301), the eyepiece system 200 is disposed between the display 100 and the optical waveguide 301, and the optical axis of the eyepiece system 200 is perpendicular to the display 100;

Wherein, the divergent light of the line field of view of the display 100 passes through the eyepiece system 200 and becomes parallel light of angular field distribution, and the parallel light of each field of view passes through the optical waveguide 301 and then expands out of the array, when the eyes are blind The display planes displayed on the display 100 can be obtained by overlapping the exit pupil planes 400 of the optical system.

In an example, as shown in FIG. 7, the optical waveguide 301 is a horizontally extending waveguide, the optical system further includes a vertical expansion waveguide 302, and the eyepiece system 200 is placed in the display 100 and the vertical optical waveguide 302. between;

The divergent light of the line field of view of the display 100 is converted into parallel light of the angular field of view after passing through the eyepiece system 200, and the parallel light of each field of view is expanded by the vertical expansion waveguide 302 and the horizontal expansion waveguide 301 to form a two-dimensional distribution. The extended array of the pupils can obtain the display information displayed on the display 100 when the eyelids coincide with the exit pupil plane of the optical system.

The horizontally-expanded waveguide 301 and the vertically-expanded waveguide 302 are vertically and closely connected to each other (as shown in FIG. 7), or a horizontally-expanded waveguide 301 and a vertically-expanded waveguide 302 are disposed on a substrate.

In an example, display 100 can be an organic light emitting diode (OLED), a liquid crystal display (LCD), or a liquid crystal on silicon (LCOS).

In an example, eyepiece system 200 includes at least one lens element, and each element is disposed along the optical axis of eyepiece system 200.

The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to be limiting; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art will understand that The technical solutions described in the embodiments are modified, or some of the technical features are replaced by equivalents; and the modifications or substitutions do not deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

An optical waveguide, characterized in that the optical waveguide comprises at least one first substrate and an extension waveguide, the first substrate and the extension waveguide are connected, and the extension waveguide comprises a plurality of mutually embedded obliquely parallel to each other a semipermeable membrane of the substrate, at least one of left and right sides of the optical waveguide is provided with a light absorbing material;

Wherein, after the incident light enters the extended waveguide, a plurality of mutually parallel outgoing rays are emitted; and when the incident light enters the extended waveguide and the reflected light reflected by the at least one semipermeable film enters the first substrate, the first Basement total reflection propagates to a side of the optical waveguide on which the light absorbing material is disposed, or that reflected light that is incident on the extended waveguide through the at least one semipermeable membrane propagates through the first substrate to the light The waveguide is provided with a side surface of the light absorbing material.
The optical waveguide according to claim 1, wherein the optical waveguide further comprises at least one second substrate, and the first substrate, the extension waveguide, and the second substrate are stacked;

After the incident light enters the second substrate through the reflected light reflected by the extended waveguide through the at least one semipermeable membrane, the second substrate is totally reflected and propagated to the side of the optical waveguide provided with the light absorbing material, or The reflected light reflected by the incident light into the extended waveguide through the at least one semipermeable membrane propagates through the second substrate to a side of the optical waveguide where the light absorbing material is disposed.
The optical waveguide according to claim 2, wherein a pitch of any two adjacent semipermeable membranes is greater than or equal to a product of a thickness of said expanded waveguide and tan α, and is not larger than a pupil size of a human eye, said α being First field of view.
The optical waveguide according to claim 3, wherein said plurality of semipermeable membranes comprise a first semipermeable membrane and said second semipermeable membrane, said first semipermeable membrane being adjacent to said optical waveguide adjacent to said incident light spot On one side, a side of the second semi-permeable membrane from the optical waveguide adjacent to the incident light spot is larger than a side of the first semi-permeable membrane from the optical waveguide adjacent to the incident light spot, the first semi-permeable membrane and the The second semi-permeable membrane is adjacent to each other; the first semi-permeable membrane and the second semi-permeable membrane have a first pitch, and the first pitch is larger than the size of the incident spot.
The optical waveguide according to claim 4, wherein said plurality of semipermeable membranes further comprise a plurality of third semipermeable membranes, at least one of said third semipermeable membranes being adjacent to said second semipermeable membrane.
The optical waveguide according to claim 5, wherein a distance between said second semipermeable membrane and said adjacent third semipermeable membrane is a second pitch, and any two adjacent said third half The spacing between the permeable membranes is equal to the second spacing.
The optical waveguide according to claim 5, wherein a distance between said second semipermeable membrane and an adjacent said third semipermeable membrane and between any two adjacent said third semipermeable membranes The spacing is a third spacing, and the third spacing is sequentially decreasing along the direction of the first semipermeable membrane toward the second semipermeable membrane.
The optical waveguide according to any one of claims 1 to 7, wherein the thickness of the substrate is less than or equal to a product of twice the length of the optical waveguide and cotα, and the α is a first angle of view. .
The optical waveguide according to claim 8, wherein the refractive indices of the plurality of semipermeable membranes are graded such that the amount of light exiting the plurality of mutually parallel outgoing rays after the incident light enters the expanded waveguide is the same.
The optical waveguide according to claim 9, wherein the substrate and the substrate are made of the same material.
The half waveguide according to any one of claims 1 to 7, characterized in that the upper and lower surfaces of the optical waveguide are plated with an antireflection film.
An optical system, comprising: a display, an eyepiece system, and an optical waveguide according to any one of claims 1 to 11, wherein the eyepiece system is interposed between the display and the optical waveguide, the eyepiece system The optical axis is perpendicular to the display;

The divergent light of the line field of view of the display passes through the eyepiece system and becomes parallel light of angular field distribution, and the parallel light of each field of view passes through the optical waveguide and then expands out of the array, when the eyes are blind versus The exit pupil planes of the optical system coincide to obtain display information displayed on the display.
The optical system according to claim 12, wherein said optical waveguide is a horizontally extending waveguide, said optical system further comprising a vertically extending waveguide, said eyepiece system being disposed in said display and said vertically-expanding optical waveguide between;

The divergent light of the line field of view of the display passes through the eyepiece system and becomes parallel light of angular field distribution, and the angular parallel light of each angle is extended through the vertical expansion waveguide and the horizontal expansion waveguide to form two The expanded distribution of the dimensional distribution is obtained by displaying the display information displayed on the display when the human eye is coincident with the exit pupil plane of the optical system.