WO2022050519A1

WO2022050519A1 - Optical system of head mounted display and head mounted display with same

Info

Publication number: WO2022050519A1
Application number: PCT/KR2021/001093
Authority: WO
Inventors: 박재완; 한동호; 최장호; 유선영; 이상준
Original assignee: 주식회사 맥스트; 주식회사 파노비젼
Priority date: 2020-09-02
Filing date: 2021-01-27
Publication date: 2022-03-10
Also published as: KR102201723B1

Abstract

Disclosed are an optical system of a head mounted display and a head mounted display with same. The optical system, according to one disclosed embodiment, comprises: a display panel for generating image light; a reflective polarizing plate for reflecting one polarized component among polarized components of the image light; a convex curved mirror for enlarging the image light reflected from the reflective polarizing plate, and reflecting same toward the reflective polarizing plate; a phase shift film disposed between the reflective polarizing plate and the convex curved mirror so as to change the direction of polarization of the image light; an incident lens for collimating the image light which has been reflected from the convex curved mirror and transmitted through the reflective polarizing plate; and a waveguide having the light, collimated by the incident lens, incident thereon, and emitting the incident image light toward an eye of a user.

Description

Optical system of head mounted display and head mounted display having same

Embodiments of the present invention relate to head mounted displays.

A head mounted display is a device that displays an image while worn on a user's head. Recently, a technology for providing content of virtual reality or augmented reality using a head mounted display is increasing.

The disclosed embodiment is to provide an optical system of a head mounted display capable of obtaining a wider viewing angle while reducing the thickness of the optical system, and a head mounted display having the same.

The disclosed embodiment is to provide an optical system for a head mounted display having an inverse active exit pupil expansion function and a head mounted display having the same.

On the other hand, the technical problems to be achieved in the present invention are not limited to the technical problems mentioned above, and other technical problems not mentioned are clearly to those of ordinary skill in the art to which the present invention belongs from the description below. can be understood

An optical system of a head mounted display according to an embodiment disclosed herein includes: a display panel for generating image light; a reflective polarizing plate that reflects one of the polarization components of the image light; a convex curved mirror for enlarging the image light reflected from the reflective polarizing plate and reflecting it toward the reflective polarizing plate; a phase shift film disposed between the reflective polarizing plate and the convex curved mirror and configured to change a polarization direction of the image light; an incident lens for collimating the image light reflected from the convex curved mirror and transmitted through the reflective polarizing plate; and a waveguide on which the light collimated by the incident lens is incident, and a waveguide for emitting the incident image light toward the user's eye, wherein the waveguide includes: a first surface on which the light collimated by the incident lens is incident; a second surface provided parallel to the first surface and emitting the image light totally reflected from the first surface toward the user's eye; and a plurality of inclined portions provided on the second surface in the waveguide to be spaced apart from each other and parallel to each other, and inclined at a predetermined angle to the second surface, wherein the entrance surface of the waveguide is collimated through the incident lens. The image light is provided to be inclined at a predetermined angle from the first surface so that the image light is totally reflected from the first surface, and the inclination angle θ _i of the entrance surface of the waveguide and the inclination angle θ _r of the inclined portion are the relationship according to the following equation have,

(Equation)

The incident angle θ ₀ of the image light collimated by the incident lens and the inclination angle θ _i of the entrance face have a relationship according to the following equation,

(Equation)

n ₁ : refractive index of the waveguide

The incident angle θ ₀ is an angle at which the image light collimated by the incident lens is inclined with respect to an axis perpendicular to the entrance surface of the waveguide, and the inclination angle θ _i is the angle at which the entrance surface of the waveguide is the second 1 is an inclined angle with respect to the surface, and the image light collimated by the relationship according to the above equation is totally reflected from the first surface, is incident on the inclined portion, and is reflected from the inclined portion and is emitted toward the user's eye.

The inclined portion may be partially reflectively coated to partially reflect the image light totally reflected from the first surface to change the direction of the image light toward the eye side of the user.

The inclined portion may be provided with a length smaller than a width of the waveguide, one end connected to the second surface, and the other end spaced apart from the first surface.

The image light collimated by the incident lens may be primarily focused before reaching the inclined portion, and may be provided to be secondary focused in front of the user's eyes by the inclined portion after being totally reflected on the first surface.

A plurality of the inclined portions are produced by injection molding individually, a plurality of pieces are arranged in a line so as to be in contact with each other, and then partially reflective coated on one surface, and the plurality of portions are rotated at a predetermined angle to have an inclination with respect to the second surface. It may be provided by being bonded to the second surface of the waveguide.

The inclined portion may be made of a material having the same refractive index as that of the waveguide.

The phase shift film is configured to displace the polarization direction of the image light reflected from the reflective polarizing plate by λ/4 (λ: wavelength of the image light), and displace the polarization direction of the image light reflected from the convex curved mirror by λ/4 catalog may be prepared.

The field of view (FoV) according to the image light is set by the incident angle θ ₀ determined by the above equations, and the relationship between the incident angle θ ₀ and the viewing angle of the image light is in the following equation can be expressed by

(Equation)

An optical system of a head mounted display according to another disclosed embodiment has a first surface and a second surface parallel to each other, and image light collimated by the optical system is incident on the first surface, and the incident image light a waveguide for emitting the light to the user's eye side through the second surface; and a plurality of inclined portions provided on the second surface of the waveguide to be spaced apart from each other and parallel to each other and provided to be inclined at a predetermined angle from the second surface, wherein the entrance surface of the waveguide includes image light collimated through the optical system. It is provided to be inclined at a certain angle from the first surface so as to be totally reflected from the first surface, and the inclination angle θ _i of the entrance surface of the waveguide and the inclination angle θ _r of the inclination portion have a relationship according to the following equation,

(Equation)

n ₁ : refractive index of the waveguide

The incident angle θ ₀ is an angle at which the image light collimated by the optical system is inclined with respect to an axis perpendicular to the entrance surface of the waveguide, and the inclination angle θ _i is the angle at which the entrance surface of the waveguide is the first It is an angle inclined with respect to the surface, and by the relationship according to the above equation, the collimated image light is totally reflected from the first surface, is incident on the inclined portion, is reflected from the inclined portion, and can be emitted toward the user's eye. there is.

According to the disclosed embodiment, by causing the primary focused image light to be secondary focused in front of the user's eyes through a plurality of inclinations in the waveguide, the area in which the user can check the entire image can be expanded and the viewing angle can be expanded. be able to That is, since a wide viewing angle can be realized by re-activating the already-focused image light through a plurality of inclinations in the waveguide, users having various eye intervals or eye positions can comfortably view the virtual image.

In addition, by setting the relationship between the inclination angle of the entrance surface of the waveguide and the inclination angle of the inclined portion so that the image light collimated by the incident lens is totally reflected on the first surface of the waveguide and the number of total reflections is minimized, the increase in optical aberration is reduced can be minimized.

In addition, by expanding the image light generated by the display panel through the convex mirror, it is possible to minimize the thickness of the optical system.

In addition, by partially reflective coating on the inclined portion in the waveguide, when the user wears the head mounted display, the user can view the external background image while viewing the virtual image, thereby maximizing the augmented reality effect.

In addition, by individually injection molding the inclined portions in the waveguide and then bonding them into the waveguide, injection mass production is possible and the unit cost of the product can be lowered.

1 is a view schematically showing a head mounted display according to an embodiment of the present invention;

2 is a view showing an optical system of a head mounted display having an inverse eye-box extensible function according to an embodiment of the present invention;

3 is a view for explaining a state of inversely activating a previously focused image light in an optical system of a head mounted display according to an embodiment of the present invention;

4 is a view illustrating a state in which an exit pupil is expanded in an optical system of a head mounted display according to an embodiment of the present disclosure;

5 is a diagram illustrating a relationship between an entrance angle of a waveguide and an inclination angle of an inclined portion in an optical system of a head mounted display according to an embodiment of the present disclosure;

6 is a diagram illustrating a relationship between an inclination angle of an entrance surface of a waveguide and an incident angle of image light in an optical system of a head mounted display according to an exemplary embodiment;

7 is a diagram illustrating a method of forming an inclined portion in a waveguide in an optical system of a head mounted display according to an embodiment of the present disclosure;

Hereinafter, specific embodiments of the present invention will be described with reference to the drawings. The following detailed description is provided to provide a comprehensive understanding of the methods, devices, and/or systems described herein. However, this is merely an example, and the present invention is not limited thereto.

In describing the embodiments of the present invention, if it is determined that the detailed description of the known technology related to the present invention may unnecessarily obscure the gist of the present invention, the detailed description thereof will be omitted. And, the terms to be described later are terms defined in consideration of functions in the present invention, which may vary according to intentions or customs of users and operators. Therefore, the definition should be made based on the content throughout this specification. The terminology used in the detailed description is for the purpose of describing embodiments of the present invention only, and should in no way be limiting. Unless explicitly used otherwise, expressions in the singular include the meaning of the plural. In this description, expressions such as “comprising” or “comprising” are intended to indicate certain features, numbers, steps, acts, elements, some or a combination thereof, one or more other than those described. It should not be construed to exclude the presence or possibility of other features, numbers, steps, acts, elements, or any part or combination thereof.

In the following description, the terms "transmission", "communication", "transmission", "reception" and other similar meanings of a signal or information are not only directly transmitted from one component to another component, but also a signal or information This includes passing through other components. In particular, to “transmit” or “transmit” a signal or information to a component indicates the final destination of the signal or information and does not imply a direct destination. The same is true for "reception" of signals or information. In addition, in this specification, when two or more data or information are "related", it means that when one data (or information) is acquired, at least a part of other data (or information) can be acquired based thereon.

Meanwhile, directional terms such as upper side, lower side, one side, the other side, etc. are used in connection with the orientation of the disclosed drawings. Since components of embodiments of the present invention may be positioned in various orientations, the directional terminology is used for purposes of illustration and not limitation.

Also, terms such as first and second may be used to describe various components, but the components should not be limited by the terms. The above terms may be used for the purpose of distinguishing one component from another component. For example, without departing from the scope of the present invention, a first component may be referred to as a second component, and similarly, a second component may also be referred to as a first component.

1 is a view schematically showing a head mounted display according to an embodiment of the present invention.

Referring to FIG. 1 , a head mounted display 100 is provided to be worn on a user's head, and refers to a device for displaying and providing content to a user through a display screen. The head mounted display 100 may display various contents such as 3D contents, augmented reality contents, virtual reality contents, and images on a screen using an image display means. Here, the image display means is for visually displaying various types of content, and may include, for example, an LCD panel, an OLED panel, an LCoS panel, a PDP, a transparent display, and the like.

The head mounted display 100 may be implemented as various types of devices (eg, including smart glasses) configured to be worn on a user's head. In an exemplary embodiment, the head mounted display 100 may be provided in a see-through form.

2 is a diagram illustrating an optical system of a head mounted display having an inverse eye-box extensible function according to an embodiment of the present invention.

Referring to FIG. 2 , the optical system 102 of the head mounted display 100 includes a display panel 111 , a reflective polarizer 113 , a phase shift film 115 , a convex mirror 117 , and an incident lens 119 . ), a waveguide 121 , and an inclined portion 123 .

The display panel 111 may generate image light of content to be displayed on the head mounted display 100 . The display panel 111 may have various forms such as an LCD panel, an OLED panel, an LCoS panel, and a PDP.

The reflective polarizing plate 113 may be positioned in front of the display panel 111 . The reflective polarizer 113 may reflect one of the polarization components of the image light generated by the display panel 111 toward the convex mirror 117 . That is, the reflective polarizing plate 113 may reflect either the P-wave or the S-wave of the image light generated by the display panel 111 toward the convex mirror 117 . The reflective polarizing plate 113 is formed in front of the display panel 111 with the display panel 111 to reflect one of the P-wave and the S-wave among the image light generated by the display panel 111 toward the convex mirror 117 . In contrast, it may be provided to be inclined.

The phase shift film 115 may be provided between the reflective polarizing plate 113 and the convex curved mirror 117 . In an exemplary embodiment, the phase shift film 115 may be provided on one surface of the convex curved mirror 117 , but is not limited thereto. The phase shift film 115 may change the polarization direction of the image light reflected from the reflective polarizing plate 113 . For example, the phase shift film 115 may shift the polarization direction of the image light reflected from the reflective polarizing plate 113 by λ/4 (λ is the wavelength of the image light). That is, the phase shift film 115 may be a λ/4 phase shift film. In addition, the phase shift film 115 may shift the polarization direction of the image light internally reflected from the convex curved mirror 117 by λ/4 (λ is the wavelength of the image light).

The convex curved mirror 117 may be positioned in a traveling direction of the image light reflected from the reflective polarizing plate 113 . In an exemplary embodiment, the convex curved mirror 117 may be positioned on the reflective polarizing plate 113 . The convex curved mirror 117 may enlarge and internally reflect the image light reflected from the reflective polarizing plate 113 . The other surface (ie, the surface opposite to the surface on which the phase shift film 115 is formed) 117a of the convex curved mirror 117 may be coated with a reflective coating to internally reflect image light.

The polarization direction of the image light magnified and internally reflected by the convex mirror 117 is changed again while passing through the phase shift film 115 . When the phase shift film 115 is a λ/4 phase shift film, the image light reflected from the reflective polarizing plate 113 has a polarization direction shifted by λ/4 by the phase shift film 115, and a convex curved mirror ( 117), the polarization direction is displaced by λ/4 again through the phase shift film 115 after being enlarged and internally reflected, and the total displacement in the polarization direction is made by λ/2, resulting in a reflective polarizing plate 113 will pass through That is, since the image light is shifted in the polarization direction by a total of λ/2 by the phase shift film 115 , it passes through the reflective polarizing plate 113 without being reflected from the reflective polarizing plate 113 .

The incident lens 119 may be positioned between the reflective polarizing plate 113 and the waveguide 121 . In an exemplary embodiment, the incident lens 119 may be located under the reflective polarizing plate 113 . The incident lens 119 may be provided at a position opposite to the convex curved mirror 117 with respect to the reflective polarizing plate 113 . The incident lens 119 may collimate the image light passing through the reflective polarizing plate 113 to be incident on the waveguide 121 .

The waveguide 121 may be positioned in front of the user's eyes. The waveguide 121 may be provided to have a predetermined length in a vertical direction from a lower portion of the incident lens 119 . The waveguide 121 may include a first surface 121a and a second surface 121b that are parallel to each other.

The first surface 121a may be a surface on which the image light collimated by the incident lens 119 is incident. The first surface 121a may be disposed at a specific angle with the incident surface to totally reflect the image light collimated by the incident lens 119 . The second surface 121b may be a surface through which image light is emitted toward the user's eyes. The second surface 121b may emit the image light totally reflected from the first surface 121a toward the user's eyes. The second surface 121b may be a surface facing the user's eyes. The first surface 121a may be a surface opposite to the second surface 121b of the waveguide 121 .

The entrance of the waveguide 121 may be provided with a cross-sectional area wider than that of the main body (a portion where the inclined portion 123 is formed) of the waveguide 121 . Also, the entrance surface of the waveguide 121 (ie, the incident surface on which the image light collimated by the incident lens 119 is incident) may be inclined at a predetermined angle. In the entrance surface of the waveguide 121, both the maximum and minimum angles of the image light collimated by the incident lens 119 cannot pass through the waveguide 121 and are totally reflected on the first surface 121a of the waveguide 121, but , may be provided at an angle to minimize the number of total reflection. A detailed description thereof will be described later with reference to FIG. 5 .

The inclined portion 123 may be provided in the waveguide 121 . A plurality of inclined portions 123 may be provided to be spaced apart from each other in the waveguide 121 . In an exemplary embodiment, the interval between the inclined portions 123 may be within 2 mm. In this case, it is possible to provide a continuous image while reducing loss of image light.

The inclined portion 123 may be provided on the surface (ie, the second surface 121b) from which the image light is emitted within the waveguide 121 . The inclined portion 123 may be provided to be inclined at a predetermined angle from the second surface 121b to the second surface 121b. The inclined portion 123 may be provided with a length smaller than the width of the waveguide 121 . The inclined portion 123 having one end connected to the second surface 121b may be provided with the other end spaced apart from the first surface 121a.

The inclined portion 123 may partially reflect the image light totally reflected from the first surface 121a to change the direction of the image light to the user's eye direction. The inclined portion 123 may be provided with a partially reflective coating. As the inclined portion 123 is partially reflectively coated, the user can also see the image light reflected from the inclined portion 123 while viewing the external background on the other side of the waveguide 121 .

The image light whose direction is changed by the inclination part 123 is emitted toward the user's eyes through the second surface 121b. The inclination part 123 may be provided so that the collimated image light passes through a focusing point and is reversely focused again to be transmitted to the user's eyes. A detailed description thereof will be described with reference to FIG. 3 .

3 is a view for explaining a state in which a previously focused image light is reversely activated in the optical system of the head mounted display according to an embodiment of the present invention. Figure 3 (a) is a view showing a state in which the image light passing through the focusing point is reflected from a general reflective surface and transmitted to the user, Figure 3 (b) is through a partially reflected inclined portion according to the disclosed embodiment It is a diagram illustrating a state in which the focusing point is reversely activated.

Referring to FIG. 3 (a), the image light collimated by the optical system 50 intersects the maximum inclined light L1 on one side and the maximum inclined light L2 on the other side of the image light at the focusing point F. will proceed in the form. In addition, the two maximum inclined lights L1 and L2 reflected from the general reflective surface 60 toward the user are not focused and continue to diverge.

Accordingly, the light forming the image does not reach the user's pupil, so the entire screen cannot be viewed, and the entire image can be viewed only by moving the eye to the focusing point (F). have no choice but to have In addition, as the position of the eye is further away from the optical system 50 , the exit pupil becomes narrower, so there is a limit in expanding the field of view that determines the size of the virtual image.

On the other hand, referring to (b) of FIG. 3 , the image light collimated by the optical system 50 has two maximum inclined lights L1 and L2 at the primary focusing point F1 as in FIG. 3 (a). They intersect and diverge from each other.

However, the one-side maximum inclined light L1 is first reflected by the first inclined portion 71 , and the second maximum inclined light L2 is reflected from the second inclined portion 72 after passing a certain distance and has already been emitted. A secondary focusing point F2 that activates inversely is generated. That is, by creating the secondary focusing point F2 between the first and second

inclined portions

71 and 72 and the user's eye, the entire image can be checked even at a distance from the optical system 50 , It is possible to easily construct an optical system with an extension of the exit pupil and a wide viewing angle.

That is, the two maximum oblique lights L1 and L2 that are emitted after passing through the primary focusing point F1 may be secondarily focused again through the plurality of

inclination units

71 and 72 . At this time, since the two maximum oblique lights L1 and L2 intersect at the secondary focusing point F2 formed in front of the user's eyes, the entire image can be checked from the user's eyes and a wide viewing angle can be configured. there will be

Meanwhile, in the disclosed embodiment, it is possible to expand the exit pupil not only for a single beam but also for a group of image beams in a bundle. 4 is a diagram illustrating a state in which an exit pupil is expanded in an optical system of a head mounted display according to an embodiment of the present disclosure.

Referring to FIG. 4 , a bundle of image rays collimated by the incident lens 119 is incident into the waveguide 121 to form a primary exit pupil region E1 (ie, primary focusing region). In this case, the primary exit pupil region E1 may be formed before reaching the inclined portion 123 . In addition, the image beam group is totally reflected from the first surface 121a and then reflected from the inclined portions 123 formed on the second surface 121b provided in parallel with the first surface 121a, respectively, in front of the user's eyes. Again, the secondary exit pupil region E2 (ie, secondary focusing region) is formed.

In this way, the bundle of image beams passing through the primary exit pupil region E1 forms the secondary exit pupil region E2 in front of the user's eyes through the plurality of inclined portions 123 partially reflectively coated, so that the optical system (including the display panel 111, the reflective polarizer 113, the phase shift film 115, the convex mirror 117, and the incident lens 119) to increase the area in which the entire image can be checked even at a long distance and, accordingly, it is possible to easily configure a wide viewing angle.

Referring to FIG. 5 , the entrance surface 121c of the waveguide 121 may be inclined at a predetermined angle θ _i with the first surface 121a. That is, the entrance surface 121c of the waveguide 121 on which the image ray group of the bundle collimated through the optical system is incident is constant so that all the image ray groups of the incident bundle are totally reflected on the first surface 121a of the waveguide 121 . The angle θ _i may be inclined.

Here, in order for the optical axis LX of the bundled image beam group to be emitted in parallel to the user's eye direction, the inclination angle θ _i of the entrance surface 121c of the waveguide 121 and the inclination angle of the inclined portion 123 ( θ _r ) may have a relationship as in Equation 1 below.

(Equation 1)

Using the relationship of Equation 1, the inclination angle θ _i of the entrance surface 121c of the waveguide 121 capable of limiting the number of total reflections within the waveguide 121 to 1 to 2 and the It becomes possible to set the inclination angle θ _r . As described above, by minimizing the number of total reflections in the waveguide 121 , it is possible to minimize an increase in optical aberration caused by an increase in the number of total reflections.

6 is a diagram illustrating a relationship between an inclination angle of an entrance surface of a waveguide and an incident angle of image light in an optical system of a head mounted display according to an exemplary embodiment.

Referring to FIG. 6 , the field of view (FoV) that determines the size of the virtual screen according to the image light is the angle (θ) at which the image light collimated by the optical system is incident on the entrance surface 121c of the waveguide 121 . ₀ ) and has the same relationship as Equation 2 below. Here, the incident angle θ ₀ of the image light may mean an angle inclined with respect to an axis perpendicular to the entrance surface 121c.

(Equation 2)

In addition, the image light incident on the entrance surface 121c of the waveguide 121 is refracted by the refractive index of the waveguide 121 inside the waveguide 121 . Here, the incident angle θ ₀ of the image light and the refraction angle θ ₁ refracted by the refractive index of the waveguide 121 have the same relationship as in Equation 3.

(Equation 3)

Here, n ₁ represents the refractive index of the waveguide 121 .

In addition, the angle θ ₂ of the image light totally reflected from the first surface 121a of the waveguide 121 is the inclination angle θ _i of the entrance surface 121c of the waveguide 121 and the relation of Equation 4 below will have

(Equation 4)

Here, the angle θ ₂ of the totally reflected image light must be greater than the total internal reflection critical angle θ _c of the waveguide 121 as shown in Equation 5 below.

(Equation 5)

here,

Therefore, Equation 5 can be expressed again as Equation 6 below.

(Equation 6)

In addition, Equation 6 can be expressed as a relationship between the incident angle θ ₀ of the image light and the inclination angle θ _i of the entrance surface 121c of the waveguide 121 as in Equation 7 .

(Equation 7)

Using the relationship of Equation 7, it is possible to set a maximum viewing angle that determines the size of a virtual image that is totally reflected in the waveguide 121 and transmitted to the user through the inclination unit 123 . In the disclosed embodiment, it is possible to minimize the number of times that image light is coaxially incident on the entrance surface of the waveguide (that is, constituting a coaxial optical system) and is totally reflected from the surface of the waveguide according to the relationship of the above equation.

Referring to FIG. 7 , a plurality of inclined portions 123 to be provided in the waveguide 121 may be respectively formed by injection molding ( FIG. 7A ). Here, a plurality of inclined portions 123 are provided in the form of a plate to be provided in parallel with each other in the waveguide 121 , and the shape may be provided in any one of a parallelogram, a triangle, a rectangle, and a trapezoid.

Also, in order to prevent the virtual image from being distorted or deformed by the change of the refractive index, the inclined portion 123 may be formed by injection molding with a material having the same refractive index as that of the waveguide 121 .

Next, after arranging the plurality of inclined portions 123 in a line so as to be in contact with each other, partial reflection coating may be performed on one surface of the plurality of inclined portions 123 ( FIG. 7B ).

Next, the plurality of inclined portions 123 may be rotated at the same angle to have an inclination, and the partially reflective coated surfaces may be arranged to be parallel to each other (FIG. 7(c)).

Next, the plurality of inclined portions 123 inclined at a predetermined angle may be bonded to the second surface 121b of the waveguide 121 (FIG. 7(d)). In this case, the same image light as the image light partially reflected through each inclined part 123 partially passes through the corresponding inclined part 123 and is partially reflected again at the next inclined part 123 , so that an additional exit pupil expansion function is performed. will have

Although representative embodiments of the present invention have been described in detail above, those of ordinary skill in the art to which the present invention pertains will understand that various modifications are possible within the limits without departing from the scope of the present invention with respect to the above-described embodiments. . Therefore, the scope of the present invention should not be limited to the described embodiments, but should be defined by the claims described below as well as the claims and equivalents.

Claims

a display panel that generates image light;

a reflective polarizing plate that reflects one of the polarization components of the image light;

a convex curved mirror for magnifying the image light reflected from the reflective polarizing plate and reflecting it toward the reflective polarizing plate;

a phase shift film disposed between the reflective polarizing plate and the convex curved mirror to change a polarization direction of the image light;

an incident lens for collimating the image light reflected from the convex curved mirror and transmitted through the reflective polarizing plate; and

and a waveguide through which the light collimated by the incident lens is incident and the incident image light is emitted toward the user's eye,

The waveguide,

a first surface onto which light collimated by the incident lens is incident;

a second surface provided parallel to the first surface and emitting image light totally reflected from the first surface toward the user's eye; and

A plurality of inclination portions provided on the second surface in the waveguide are spaced apart from each other and provided in parallel to each other and inclined at a predetermined angle from the second surface;

The entrance surface of the waveguide is provided to be inclined at a predetermined angle from the first surface so that the image light collimated through the incident lens is totally reflected on the first surface,

The inclination angle (θ i ) of the entrance surface of the waveguide and the inclination angle (θ r ) of the inclination portion have a relationship according to the following equation,

(Equation)

The incident angle θ 0 of the image light collimated by the incident lens and the inclination angle θ i of the entrance face have a relationship according to the following equation,

(Equation)

n 1 : refractive index of the waveguide

The incident angle θ 0 is an angle at which the image light collimated by the incident lens is inclined with respect to an axis perpendicular to the entrance surface of the waveguide,

The inclination angle (θ i ) is an angle at which the entrance surface of the waveguide is inclined with respect to the first surface,

The image light collimated by the relationship according to the equation is totally reflected from the first surface, is incident on the inclined portion, is reflected from the inclined portion, and is output to the user's eye side.
The method according to claim 1,

The inclined portion,

and partially reflective coating to change the direction of the image light toward the eye of the user by partially reflecting the image light totally reflected from the first surface.
The method according to claim 1,

The inclined portion,

The optical system of the head mounted display, which is provided with a length smaller than the width of the waveguide, one end connected to the second surface, and the other end provided to be spaced apart from the first surface.
The method according to claim 1,

The image light collimated by the incident lens is primarily focused before reaching the slope, and after being totally reflected on the first surface, is provided to be secondary focused in front of the user's eye by the slope. The optical system of the display.
The method according to claim 1,

The inclined portion,

A plurality of pieces are individually injection molded and produced, a plurality of pieces are arranged in a line so as to be in contact with each other, and then partially reflective coated on one surface, and the plurality of pieces are rotated at an angle to have an inclination with respect to the second surface, and then the second of the waveguide An optical system of a head mounted display, which is provided by bonding to a surface.
The method according to claim 1,

The inclined portion,

The optical system of the head mounted display, which is provided with a material having the same refractive index as that of the waveguide.
The method according to claim 1,

The phase shift film,

Displaces the polarization direction of image light reflected from the reflective polarizer by λ/4 (λ: wavelength of image light), and is provided to shift the polarization direction of image light reflected from the convex curved mirror by λ/4 The optical system of the display.
The method according to claim 1,

The field of view (FoV) according to the image light is set by the incident angle θ 0 determined by the above equations, and the relationship between the incident angle θ 0 and the viewing angle of the image light is in the following equation Represented by the optical system of the head mounted display.

(Equation)
a waveguide having first and second surfaces parallel to each other, the image light collimated by an optical system is incident on the first surface, and the incident image light is emitted to the user's eye side through the second surface; and

A plurality of inclination portions are provided on the second surface of the waveguide to be spaced apart from each other and parallel to each other, and inclined at a predetermined angle from the second surface;

The entrance surface of the waveguide is provided to be inclined at a predetermined angle from the first surface so that the image light collimated through the optical system is totally reflected from the first surface,

The inclination angle (θ i ) of the entrance surface of the waveguide and the inclination angle (θ r ) of the inclination portion have a relationship according to the following equation,

(Equation)

The incident angle θ 0 of the image light collimated by the incident lens and the inclination angle θ i of the entrance face have a relationship according to the following equation,

(Equation)

n 1 : refractive index of the waveguide

The incident angle θ 0 is an angle at which the image light collimated by the optical system is inclined with respect to an axis perpendicular to the entrance surface of the waveguide,

The inclination angle (θ i ) is an angle at which the entrance surface of the waveguide is inclined with respect to the first surface,

According to the relationship according to the above equation, the collimated image light is totally reflected from the first surface, is incident on the inclined portion, is reflected from the inclined portion, and is output to the user's eye side.
A head mounted display comprising the optical system according to any one of claims 1 to 9.