KR20240013445A - Optical device for augmented reality with expanded eyebox using diffractive optical elements - Google Patents

Abstract

The present invention is an optical device for eyebox expanded augmented reality using a diffractive optical element, comprising: a first optical means through which virtual image light emitted from an image emitting unit travels; a first optical element disposed in the first optical means and emitting virtual image light traveling through the inside of the first optical means to the second optical means; a second optical means for transmitting real object image light emitted from a real object to the pupil of the user's eye, and through which virtual image image light emitted from the first optical element travels; and a plurality of second optical elements embedded in the second optical means and providing a virtual image to the user by transmitting virtual image light traveling through the second optical means to the pupil of the user's eye. The first optical element is a diffractive optical element or a holographic optical element, the first optical element extends in a first direction and is disposed in the first optical means, and the plurality of second optical elements are, An optical device for augmented reality is provided, which is disposed at intervals in a second direction within the second optical means.

Description

Optical device for eyebox expandable augmented reality using diffractive optical elements {OPTICAL DEVICE FOR AUGMENTED REALITY WITH EXPANDED EYEBOX USING DIFFRACTIVE OPTICAL ELEMENTS}

The present invention relates to an optical device for augmented reality, and more specifically, to an optical device for augmented reality that can provide an expanded eye box using a diffractive optical element.

As is well known, Augmented Reality (AR) refers to virtual image information augmented from visual information in the real world by providing virtual images provided by computers, etc., over real images in the real world. It refers to the technology provided to users.

A device for implementing such augmented reality requires an optical combiner that allows virtual images to be observed simultaneously with actual images in the real world. As such optical synthesizers, the half mirror method and the holographic/diffractive optical elements (HOE/DOE) method are known.

The semi-mirror method has problems in that the transmittance of the virtual image is low and that it is difficult to provide a comfortable fit because the volume and weight are increased to provide a wide viewing angle. In order to reduce volume and weight, technologies such as LOE (Light guide Optical Element), which places a plurality of small semi-mirrors inside a waveguide, have been proposed, but these technologies also require that the image light of the virtual image travels through the semi-mirrors inside the waveguide. The manufacturing process is complicated because it must be passed multiple times, and there is a limitation in that optical uniformity can easily be lowered due to manufacturing errors.

In addition, the holographic/diffractive optical device method generally uses nanostructured grids or diffraction gratings, but since these are manufactured through very precise processes, they have limitations in that the manufacturing cost is high and the yield for mass production is low. Additionally, it has limitations in terms of color uniformity and low image clarity due to differences in diffraction efficiency depending on the wavelength band and angle of incidence. Holographic/diffractive optical elements are often used in conjunction with waveguides such as the LOE described above, and therefore still suffer from the same problems.

Additionally, conventional optical synthesizers have a limitation in that the virtual image becomes out of focus when the user changes the focal distance while gazing at the real world. To solve this problem, a technology has been proposed that uses a prism that can adjust the focal length of the virtual image or a variable focus lens that can electrically control the focal length. However, this technology also has problems in that the user must perform separate operations to adjust the focal distance and also requires separate hardware and software for controlling the focal distance.

In order to solve these problems of the prior art, the present applicant has developed a technology to project a virtual image onto the retina through the pupil using a pin mirror-shaped reflection unit smaller than the human pupil ( (See Prior Art Document 1).

FIG. 1 is a diagram showing an optical device 100 for augmented reality as described in Prior Art Document 1.

The optical device 100 for augmented reality in FIG. 1 includes an optical means 10 and a reflection unit 20.

The image emitting unit 30 is a means for emitting virtual image image light, for example, a micro display device that displays a virtual image on a screen and emits virtual image image light corresponding to the displayed virtual image, and image light emitted from the micro display device. It may be provided with a light conversion unit that transmits to the reflection unit 20. Here, the light conversion unit is a means for emitting virtual image light along the intended optical path and focal distance, for example, a concave mirror that reflects and emits incident virtual image light to enlarge the virtual image, or is a concave mirror that reflects and emits incident light to enlarge the virtual image. It may be an optical element such as a collimator that converts parallel light and emits it.

The optical means 10 transmits real object image light, which is image light emitted from objects in the real world, into the pupil 40, while emitting virtual image image light reflected from the reflector 20 into the pupil 40. It is a means of performing it.

The optical means 10 may be formed of a transparent resin material, such as a spectacle lens, and may be fixed by a frame (not shown) such as an eyeglass frame.

The reflector 20 reflects the virtual image light emitted from the image emitter 30 and transmits it toward the user's pupil 40.

The reflector 20 is embedded and disposed inside the optical means 10.

The reflection portion 20 in FIG. 1 is formed in a size smaller than the human pupil. It is known that the general pupil size of a person is about 4 to 8 mm, so the reflection portion 20 is preferably formed to be 8 mm or less, and more preferably 4 mm or less.

By forming the reflector 20 to be 8 mm or less, the depth of field for light incident on the pupil 40 through the reflector 20 can be made close to infinity, that is, very deep.

Here, depth refers to the range recognized as being in focus. As the depth of field deepens, the range of focal distance for the virtual image correspondingly widens. Therefore, even if the user changes the focal distance to the real world while gazing at the real world, the virtual image is always recognized as being in focus regardless. This can be seen as a kind of pinhole effect.

Therefore, even if the user changes the focal distance to the real object, the user can always observe a clear virtual image.

FIGS. 2 to 4 are diagrams showing the optical device 200 for augmented reality as disclosed in prior art document 2, where FIG. 2 is a side view, FIG. 3 is a perspective view, and FIG. 4 is a front view.

The optical device for augmented reality 200 of FIGS. 2 to 4 has the same basic principle as the optical device 100 for augmented reality of FIG. 1, but the reflector 20 has a plurality of reflections to widen the viewing angle and eye box. It is composed of modules and disposed inside the optical means 10 in the form of an array, and the virtual image image light emitted from the image emitting unit 30 is totally reflected inside the optical means 10 to form a reflecting unit 20. There is a difference in that it is delivered as .

In FIGS. 2 to 4 , reference numerals 21 to 26 indicate only reflection modules seen from the side as in FIG. 2 , and the reflection unit 20 refers to the entire plurality of reflection modules.

As described above, each of the plurality of reflection modules is preferably formed to have a size of 8 mm or less, and more preferably 4 mm or less.

2 to 4, the virtual image light emitted from the image emitting unit 30 is totally reflected on the inner surface of the optical means 10 and then transmitted to the reflection modules, and the reflection modules reflect the incident virtual image light. and transmits it to the pupil (40).

Therefore, the reflection modules must be arranged to have an appropriate inclination angle inside the optical means 10 as shown, taking into account the positions of the image emitting unit 30 and the pupil 40.

This optical device 200 for augmented reality has the advantage of being able to widen the eye box compared to the optical device 100 for augmented reality in FIG. 1 . However, when this augmented reality optical device 200 is placed in front of the pupil 40, the eyebox in the horizontal axis direction (x-axis direction) is determined by the length of the light conversion unit included in the image emitter 30, , the eyebox in the vertical axis direction (y-axis direction) is determined by the arrangement structure of the reflectors 21 to 26.

Therefore, in order to expand the eyebox in the horizontal direction, an optical converter with a longer horizontal axis must be used. However, as the length of the optical converter increases, the form factor such as size, weight, and volume increases, and the design of the optical path becomes more difficult. The problem is that it becomes complicated.

Republic of Korea Patent Publication No. 10-2018-0028339 (published on March 16, 2018) Republic of Korea Patent Publication No. 10-2192942 (announced on December 18, 2020)

The present invention is intended to solve the problems described above, and aims to provide an optical device for augmented reality having an expanded eye box using a diffractive optical element.

In particular, the purpose of the present invention is to provide an optical device for augmented reality that can expand the two-dimensional eyebox of the x-axis and y-axis while maintaining the form factor.

In order to solve the problems described above, the present invention is an optical device for eye-box expansion type augmented reality using a diffractive optical element, comprising: a first optical means through which virtual image light emitted from an image emitter travels through the interior; a first optical element disposed in the first optical means and emitting virtual image light traveling through the inside of the first optical means to the second optical means; a second optical means for transmitting real object image light emitted from a real object to the pupil of the user's eye, and through which virtual image image light emitted from the first optical element travels; and a plurality of second optical elements embedded in the second optical means and providing a virtual image to the user by transmitting virtual image light traveling through the second optical means to the pupil of the user's eye. The first optical element is a diffractive optical element or a holographic optical element, the first optical element extends in a first direction and is disposed in the first optical means, and the plurality of second optical elements are, An optical device for augmented reality is provided, which is disposed at intervals in a second direction within the second optical means.

Here, the first direction may be a direction parallel to any one of line segments included in a plane perpendicular to a straight line in the frontal direction from the pupil.

Additionally, the second direction may be a direction that is not parallel to the first direction.

Additionally, the second direction may be perpendicular to the first direction.

Additionally, the virtual plane formed by the first direction and the second direction may be a two-dimensional plane that can be observed from the user's pupil when the augmented reality optical device is placed in front of the user's pupil.

Additionally, the second direction may be a direction parallel to any one of line segments perpendicular to the first direction among line segments included in a plane perpendicular to a straight line in the frontal direction from the pupil.

Additionally, an image emitting unit may be disposed at one end of the first optical means in the first direction.

Additionally, the first optical element may be disposed on the top, bottom, or inside of the first optical means.

Additionally, the first optical element may be disposed in the first optical means to have an inclination angle with respect to the second direction when viewed from the side with the augmented reality optical device in front of the pupil.

Additionally, each of the plurality of second optical elements may be arranged to be inclined inside the second optical means so as to transmit virtual image light traveling through the inside of the second optical means to the pupil.

In addition, the second optical means has a first surface on which virtual image image light and real object image light are emitted toward the user's pupil, and a second surface opposite the first surface and on which real object image light is incident, The virtual image light emitted from the first optical element is totally reflected on the second surface of the second optical means and transmitted to a plurality of second optical elements, and the plurality of second optical elements are of the second optical means. It may be disposed at an inclination angle inside the second optical means so that the virtual image light transmitted by total reflection from the second surface can be transmitted to the pupil.

Additionally, the plurality of second optical elements may have a plate shape extending in the first direction.

Additionally, the plurality of second optical elements may have a height of 4 mm or less when viewed from the front.

Additionally, each of the plurality of second optical elements may be composed of a plurality of optical modules.

Additionally, each of the plurality of second optical elements may be composed of a plurality of optical modules arranged to be spaced apart from each other and appear in an array form when the augmented reality optical device is viewed from the front.

Additionally, the size of the plurality of optical modules may be 4 mm or less.

Additionally, the plurality of second optical elements may be reflection means that reflect incident light.

Additionally, the plurality of second optical elements may be half mirrors that transmit part of the incident light and reflect part of it.

Additionally, the plurality of second optical elements may be any one of a refractive element, a diffractive element, and a holographic optical element, or may be configured by a combination thereof.

Additionally, the first optical means and the second optical means may be formed integrally.

According to the present invention, it is possible to provide an optical device for augmented reality having an expanded eye box using a diffractive optical element.

In particular, the present invention can provide an optical device for augmented reality that can expand the two-dimensional eyebox of the x-axis and y-axis while maintaining the form factor.

FIG. 1 is a diagram showing an optical device 100 for augmented reality as described in Prior Art Document 1.
FIGS. 2 to 4 are diagrams showing the optical device 200 for augmented reality as disclosed in prior art document 2, where FIG. 2 is a side view, FIG. 3 is a perspective view, and FIG. 4 is a front view.
FIGS. 5 to 7 are diagrams for explaining the optical device 300 for augmented reality according to an embodiment of the present invention. FIG. 5 is a perspective view, FIG. 6 is a front view, and FIG. 7 is a side view.
FIG. 8 is a diagram for explaining the arrangement structure of the second optical element 20.
FIG. 9 is a diagram for explaining the eye box in the first direction (x-axis direction) in the conventional optical device 200 of FIGS. 2 to 4, where the optical device 200 is placed in front of the pupil 40. This is the front view.
FIG. 10 is a diagram for explaining the eyebox in the first direction in the optical device 300 of FIGS. 5 to 7 when viewed in the direction indicated by A in FIG. 7 .
FIGS. 11 to 13 are diagrams for explaining an optical device 400 according to another embodiment of the present invention. FIG. 11 is a perspective view, FIG. 12 is a front view, and FIG. 13 is a side view.
FIGS. 14 to 16 are diagrams for explaining an optical device 500 according to another embodiment of the present invention. FIG. 14 is a perspective view, FIG. 15 is a front view, and FIG. 16 is a side view.
FIGS. 17 to 19 are diagrams for explaining an optical device 600 according to another embodiment of the present invention. FIG. 17 is a perspective view, FIG. 18 is a front view, and FIG. 19 is a side view.

Hereinafter, embodiments according to the present invention will be described in detail with reference to the accompanying drawings.

FIGS. 5 to 7 are diagrams for explaining an eyebox extended augmented reality optical device 300 using a diffractive optical element according to an embodiment of the present invention. FIG. 5 is a perspective view, FIG. 6 is a front view, and FIG. 7 is a side view.

However, in FIG. 7 , the image emitting unit 30 is shown as transparent for convenience of explanation.

Referring to FIGS. 5 to 7, the optical device 300 for eyebox extended augmented reality using a diffractive optical element (hereinafter simply referred to as the “optical device 300”) includes a first optical means 50 and a first optical device. It includes an element 60, a second optical means 10 and a second optical element 20.

The first optical means 50 is a means through which the virtual image light emitted from the image emitting unit 30 travels through its interior, and serves as a waveguide.

A first optical element 60 is disposed in the first optical means 50 as will be described later.

5 to 7, the first optical element 60 is disposed on the upper surface 51 of the first optical means 50.

The first optical means 50 may have a substantially rectangular parallelepiped shape as shown, and may be made of a transparent resin material or glass material.

An image emitting unit 30 is disposed at one end of the first optical means 50 as shown.

The image emitting unit 30 is a means for emitting virtual image light, which is image light corresponding to a virtual image. Here, the virtual image refers to an augmented reality image provided to the user and may be an image or video.

The image emitting unit 30 transmits the virtual image light emitted from the display unit and the display unit to display a conventionally known virtual image such as a small LCD, OLED, LCoS, or micro LED to the first optical element 60. It may include a light conversion unit (not shown).

As explained in the background technology section, the light conversion unit is a means for emitting virtual image light along the intended optical path and focal distance, for example, reflecting and emitting incident virtual image light to enlarge the virtual image. It may be a concave mirror or an optical element such as a collimator that converts incident light into parallel light and emits it.

The image emitting unit 30 may be composed of a combination of at least one of a reflecting unit, a refracting unit, and a diffractive unit combined with the display unit and the light conversion unit.

Since the image emitting unit 30 itself is not a direct object of the present invention and is known in the prior art, a detailed description thereof will be omitted here.

The virtual image image light may be emitted from the image emitter 30, be totally reflected inside the first optical means 50, and be transmitted to the first optical element 60. 5 to 7, the virtual image light is totally reflected at the upper surface 51 and the lower surface 52 of the first optical means 50 and is transmitted to the first optical element 60.

In this case, the surface of the image emitting unit 30 is disposed inclined so as to face the upper surface 51 of the first optical means 50, and one end of the first optical means 50 on which the image emitting unit 30 is disposed is also It may be formed to be inclined to correspond to the inclination angle of the image emitting unit 30.

However, this is an example, and the virtual image light emitted from the image emitter 30 may be directly transmitted to the first optical element 60 without total reflection. In this case, of course, the shape and inclination angle of the image emitting unit 30 and the first optical means 50 may have different shapes and arrangement structures.

The first optical element 60 is disposed in the first optical means 50 and performs the function of emitting virtual image light traveling through the inside of the first optical means 50 to the second optical means 10. do.

The first optical element 60 may be formed in the form of a thin plate extending in a first direction as shown and disposed on the first optical means 50 . Here, the normal line of the thin plate may be arranged to face the second surface 20 of the second optical means 10, as will be described later.

5 to 7, the first optical element 60 is disposed on the upper surface 51 of the first optical means 50, that is, outside the upper surface 51, but this is an example and is located inside the upper surface 51. It may be deployed.

Additionally, as in an embodiment described later, it may be disposed outside or inside the lower surface 52 of the first optical means 50. Additionally, it may be disposed inside the first optical means 50.

The first optical means 50 extends in a first direction, where “first direction” refers to the angle observed when the optical device 300 is placed in front of the pupil 40, as shown in FIGS. 5 to 7. It may be in a direction parallel to an imaginary line segment. In other words, the first direction may be any direction other than the direction parallel to the straight line in the frontal direction at the pupil 40.

Additionally, the first direction is preferably a direction parallel to any one of the line segments included in the plane perpendicular to the straight line in the frontal direction in the pupil 40. 5 to 7, the first direction corresponds to the x-axis direction.

Meanwhile, in the present invention, the first optical element 60 is characterized by being implemented as a diffractive optical element. Diffractive Optical Element (DOE) refers to an optical element that refracts or reflects incident light through a diffraction phenomenon. In other words, a diffractive optical element is an optical element that provides various optical functions by using the diffraction phenomenon of light.

Diffractive optical elements have the advantage of enabling aberration-free point-to-point images and a flat structure, and of being able to control aberrations such as aspherical surfaces. In addition, although the diffractive optical element has a very thin thickness of several μm, it is advantageous in reducing the volume and weight of the optical system because it plays a role similar to a general lens, prism, or mirror with a thickness of several mm.

In particular, due to the wavelength-dependent nature of the diffraction phenomenon, the diffractive optical element operates as a refracting or reflecting element only for light that matches the design wavelength band of the nanostructure, and in other wavelength bands, it is a window that simply passes light. ) plays a role.

Diffractive optical elements can be divided into reflective diffractive optical elements and transmission-type diffractive optical elements. Reflective diffractive elements refer to diffractive elements that utilize the property of reflecting light incident from a specific direction and position, and transmission-type diffractive elements. A diffractive element uses the property of transmitting light incident from a specific direction and position.

In the present invention, by implementing the first optical element 60 using such a diffractive optical element, the virtual image light transmitted from the image emitting unit 30 is copied in the first direction to expand the eye box, while the incident The virtual image light can be transmitted to the second optical means (10).

Since the basic configuration and characteristics of these diffractive optical elements, reflective diffractive optical elements, and transmission-type diffractive optical elements are known in the prior art, detailed descriptions thereof will be omitted here.

By using these diffractive optical elements, the brightness of the perspective image is secured by increasing transparency, and since the optical synthesizer structure is not observed from the outside, the appearance of the product is similar to that of regular glasses, providing an optical device for augmented reality with better aesthetics. There is an advantage to being able to do it.

This first optical element 60 is disposed in the first optical means 50 with an appropriate inclination angle so that virtual image light can be transmitted to the second optical means 10 .

5 to 7, the virtual image image light emitted from the first optical element 60 implemented as a diffractive optical element is totally reflected by the second surface 12 of the second optical means 10 and then is converted into a second optical element 60. 2 is transmitted to the optical element 20.

Accordingly, in the embodiments of FIGS. 5 to 7, the first optical element 60 is shown in FIG. 7 when viewed from the side with the optical device 300 in front of the pupil 40, considering this optical path. As shown, it may be disposed outside the upper surface 51 of the first optical means 50 so as to have an inclination angle with respect to the second direction.

Here, the second direction is a direction in which the plurality of second optical elements 20 are arranged in the second optical means 10, as will be described later.

This second direction may be a direction that is not parallel to the first direction.

Additionally, the second direction may be perpendicular to the first direction.

In addition, the second direction is a virtual direction composed of the first direction and the second direction when the augmented reality optical device 300 is placed in front of the user's pupil 40, as shown in FIGS. 5 to 7. The plane may be oriented so that it becomes a two-dimensional plane that can be observed from the user's pupil 40.

In addition, as described above, the first direction is parallel to any one of the line segments included in the plane perpendicular to the straight line in the front direction from the pupil 40 when the optical device 300 is placed in front of the pupil 40. It may be a direction, and in this case, the second direction may be a direction parallel to any one of the line segments perpendicular to the first direction among the line segments included in the plane perpendicular to the straight line in the frontal direction in the pupil 40.

To this end, as shown in FIG. 7, the upper surface 13 of the second optical means 10 is formed to be inclined when viewed from the side, and the first optical means 50 is positioned on the upper surface of the second optical means 10 ( 13) can be placed.

For example, the first optical element 60 may have a thin plate shape with a rectangular surface. In this case, it is preferable that the width direction length of the first optical element 60 when viewed from the side is formed to correspond to the width direction length of the image emitting portion 30.

In addition, the first optical element 60 has a surface on which virtual image light enters and exits extending in the first direction, thereby expanding the eye box for the virtual image light in the first direction.

The second optical means 10 is a means for transmitting real object image light emitted from real objects existing in the real world to the pupil 40 of the user's eye. In addition, the second optical means 10 also serves as a waveguide through which virtual image light transmitted from the first optical element 60 travels through its interior.

The second optical means 10 may also be made of transparent resin or glass.

The second optical means 10 has a first surface 11 through which virtual image image light and real object image light are emitted toward the user's pupil 40, and the second optical means 10 faces the first surface 11 and provides real object image light. It has a second surface 12 on which the incident occurs and a third surface 13 on which the first optical means 50 is disposed.

The virtual image image light transmitted to the second optical means 10 through the image emitting unit 30 and the first optical element 60 passes through the first surface 11 of the second optical means 10 to the pupil 40. ), and since the real object image light passes through the second surface 12 and the first surface 11 of the second optical means 10 and is transmitted to the pupil 40, the user Real object image light can be provided at the same time, thereby providing augmented reality services.

The plurality of second optical elements 20 are embedded inside the second optical means 10 and direct the virtual image light traveling through the inside of the second optical means 10 into the pupil 40 of the user's eye. It is a means of providing virtual images to users by transmitting them.

The plurality of second optical elements 20 are arranged at intervals in the second direction, and actual object image light is transmitted to the pupil 40 through the space provided by the gap between the second optical elements 20.

Here, as described above, the second direction may be a direction that is not parallel to the first direction. Additionally, the second direction is preferably perpendicular to the first direction.

In addition, as shown in FIGS. 5 to 7, the second direction is a virtual plane composed of the first direction and the second direction when the optical device 300 is placed in front of the user's pupil 40. The direction may be such that it becomes a two-dimensional plane that can be observed from the user's pupil 40.

In addition, when the optical device 300 is placed in front of the pupil 40, if the first direction is a direction parallel to any one of the line segments included in the plane perpendicular to the straight line in the front direction from the pupil 40, The second direction may be a direction parallel to any one of the line segments perpendicular to the first direction among the line segments included in the plane perpendicular to the straight line in the frontal direction in the pupil 40.

For example, in the embodiments of FIGS. 5 to 7, the first direction is the x-axis direction, so the second direction is perpendicular to the x-axis and is included in a plane perpendicular to the z-axis, which is a straight line in the frontal direction from the pupil 40. It corresponds to the y-axis perpendicular to the first direction among the line segments. Accordingly, the virtual plane formed by the first direction (x-axis direction) and the second direction (y-axis direction) becomes a two-dimensional x-y plane perpendicular to the z-axis.

This two-dimensional plane is not necessarily perpendicular to the z-axis, and may be slightly rotated about the x- or y-axis as long as it can be observed from the user's pupil 40.

In addition, the meaning that the plurality of second optical elements 20 are “arranged at intervals in the second direction” means that it is sufficient for the plurality of second optical elements 20 to be arranged at intervals from each other in the second direction. It should be noted that this does not necessarily mean that they must be arranged side by side on a straight line parallel to the second direction.

FIG. 8 is a diagram for explaining the arrangement structure of the second optical element 20.

Figure 8 is a side view viewed from the side when the optical device 300 is placed in front of the pupil 40, showing only the second direction and the second optical element 20.

Referring to (a) of FIG. 8, the plurality of second optical elements 20 have their respective centers in the second direction (y-axis direction) when viewed from the side with the optical device 300 in front of the pupil 40. They may be spaced apart and aligned side by side along a parallel straight line.

In addition, as shown in (b) of FIG. 8, when the optical device 300 is placed in front of the pupil 40 and viewed from the side, the plurality of second optical elements 20 each have their centers aligned in the second direction (y-axis). They may be spaced apart so that they are aligned side by side along a straight line having an inclination angle with respect to the direction.

In addition, as shown in (c) of FIG. 8, the plurality of second optical elements 20 each have a gentle “C” shape when viewed from the side with the optical device 300 in front of the pupil 40. They may be spaced apart so as to be located on the curve of . This is the same as shown in FIG. 7.

Here, only some of the plurality of second optical elements 20 may have this arrangement structure.

In addition to this arrangement structure, the relative positional relationship, tilt angle, total reflection, etc. of the image emitting unit 30, the first optical means 50, the first optical element 60, the second optical means 10, and the pupil 40 Of course, it can be arranged differently depending on various conditions.

Additionally, the spacing of the plurality of second optical elements 20 may all be the same, but of course, the spacing of at least some of the plurality of second optical elements 20 may be different.

Meanwhile, as shown, the plurality of second optical elements 20 may be formed as thin plates extending in the first direction, that is, the x-axis direction.

In addition, each of the plurality of second optical elements 20 is inclined inside the second optical means 10 so as to transmit the virtual image light traveling through the inside of the second optical means 10 to the pupil 40. can be placed. In this case, the plurality of second optical elements 20 have an appropriate inclination angle in consideration of the relative positions of the first optical means 50, the first optical element 60, and the pupil 40, and the second optical means 10 ) can be placed inside.

5 to 7, the virtual image light transmitted from the first optical element 60 is totally reflected on the second surface 12 of the second optical means 10 and is formed into a plurality of second optical elements 20. ) is transmitted. Accordingly, each of the plurality of second optical elements 20 can transmit the virtual image light transmitted by total reflection from the second surface 12 of the second optical means 10 to the pupil 40 in consideration of this optical path. It may be disposed at an inclination angle inside the second optical means 10 so that

In this case, each of the plurality of second optical elements 20 is shown in FIG. 8 so as not to block the virtual image light emitted from the first optical elements 60 and transmitted to the other second optical elements 20. As shown in b) or (c), the further away from the first optical element 60, the closer to the second surface 12 of the second optical means 10.

Meanwhile, as shown in FIG. 6, the plurality of second optical elements 20 may be formed so that the height when viewed from the front is smaller than the average human pupil size, that is, 8 mm or less, preferably It can be formed to be less than 4mm.

As a result, the depth of field for light entering the pupil 40 can be greatly deepened, and therefore, even if the user changes the focal distance to the real world while gazing at the real world, the virtual image remains in focus regardless of this. can achieve a pinhole effect that always recognizes it as correct.

However, if the height is too small, the diffraction phenomenon increases, so it is preferable to set it larger than 0.3 mm, for example.

Additionally, it is preferable that the plurality of second optical elements 20 are reflection means that reflect incident light.

In addition, it is preferable that the plurality of second optical elements 20 have a reflectance of 100% or a high value close to it, such as full mirrors made of metal, for example, but they may also be half mirrors that transmit part of the incident light and reflect part of it.

Additionally, the plurality of second optical elements 20 may be any one of a refractive element, a diffractive optical element, and a holographic optical element, or may be configured by a combination thereof.

Meanwhile, in the optical device 300 of FIGS. 5 to 7 , a holographic optical element (HOE) may be used as the first optical element 20 instead of a diffractive optical element. This also applies to all embodiments described later.

Next, the principle of expanding the eyebox by the optical device 300 will be described with reference to FIGS. 9 and 10 .

FIG. 9 is a diagram for explaining the eye box in the first direction (x-axis direction) in the conventional optical device 200 of FIGS. 2 to 4, where the optical device 200 is placed in front of the pupil 40. This is the front view.

Referring to the optical device 200 in Figure 9 (a), the virtual image image light emitted from one point of the display unit 31 is emitted to the optical means 10 through the light conversion unit 32, and is reflected. It is reflected by the unit 20 and transmitted to the pupil 40. At this time, the eyebox in the x-axis direction, that is, in the first direction, is determined by the length of the light conversion unit 32 in the first direction.

In the optical device 200 of FIG. 9(b), all other conditions are the same, but the length of the light conversion unit 32 in the first direction is longer than that of FIG. 9(a). Accordingly, corresponding to the length of the light conversion unit 32, the reflector 20 is also arranged more along the x-axis direction (first direction), whereby the eye box in the first direction is shown in (a) of FIG. 9 It can be seen that it is wider than .

In this way, in the conventional optical device 200 as shown in FIGS. 2 to 4, the eye box in the first direction (x-axis direction) is equal to the length of the light conversion unit 32 included in the image emitting unit 30. You can see that it depends. However, increasing the length of the light conversion unit 32 increases the form factor, complicates the design, and also complicates the manufacturing process.

Meanwhile, in FIG. 9, the eye box in the y-axis direction, which is the vertical axis, is determined by the number of reflectors 20 arranged in the y-axis direction.

FIG. 10 is a diagram for explaining the eyebox in the first direction in the optical device 300 of FIGS. 5 to 7 when viewed in the direction indicated by A in FIG. 7 .

Referring to FIG. 10, the virtual image light emitted from one point of the image emitting unit 30 is totally reflected by the upper surface 51 and the lower surface 52 of the first optical means 50 and is transmitted to the first optical element 60. is passed on. Thereafter, the first optical element 60 emits virtual image light toward the second surface 12 of the second optical means 10.

That is, the virtual image light emitted from the image emitting unit 30 is transmitted to the first optical element 60 while being totally reflected by the upper surface 51 and the lower surface 52 of the first optical means 50. It can be seen that the virtual image light is copied in the first direction (x-axis direction) and thus the eyebox in the first direction, that is, the x-axis direction, is expanded.

Also in FIG. 10, the eyebox in the y-axis direction, which is the vertical axis, is determined by the number of second optical elements 20 arranged in the y-axis direction. Therefore, while maintaining the same eyebox in the vertical y-axis direction, the eyebox in the horizontal x-axis direction, that is, in the first direction, is larger in the optical device 300 of FIG. 10 than the optical device 200 in FIG. 9. You can see that it is wide.

FIGS. 11 to 13 are diagrams for explaining an optical device 400 according to another embodiment of the present invention. FIG. 11 is a perspective view, FIG. 12 is a front view, and FIG. 13 is a side view.

The optical device 400 of FIGS. 11 to 13 has the same basic principle as the optical device 300 of FIGS. 5 to 7, but the first optical element 60 is embedded within the first optical means 50. The difference is in how they are arranged.

Except for this, other configurations of the optical device 400 are the same as those of the optical device 300 described above, so detailed description will be omitted.

FIGS. 14 to 16 are diagrams for explaining an optical device 500 according to another embodiment of the present invention. FIG. 14 is a perspective view, FIG. 15 is a front view, and FIG. 16 is a side view.

The optical device 500 of FIGS. 14 to 16 is the same as the optical device 300 of FIGS. 5 to 7, except that the first optical element 60 is located inside the lower surface 52 of the first optical means 50. There is a difference in that it is placed in . Here, of course, the first optical element 60 may be disposed on the lower outer surface of the lower surface 52 of the first optical means 50.

Except for this, other configurations of the optical device 500 are the same as those of the optical device 300 described above, so detailed description will be omitted.

FIGS. 17 to 19 are diagrams for explaining an optical device 600 according to another embodiment of the present invention. FIG. 17 is a perspective view, FIG. 18 is a front view, and FIG. 19 is a side view.

The optical device 600 of FIGS. 17 to 19 is the same as the optical device 300 of FIGS. 5 to 7, except that the plurality of second optical elements 20 each include a plurality of optical modules 21 in a pinpoint shape. There is a difference in that it is composed of .

That is, in the optical device 600, each of the plurality of second optical elements 20 is spaced apart from each other and appears in an array form when the optical device 400 is viewed from the front of the pupil 40, as shown. It consists of a plurality of optical modules 21 arranged so as to

Each of the plurality of optical modules 21 may be formed to have a size smaller than the size of a human pupil, that is, 8 mm or less, and preferably 4 mm or less, to obtain a pinhole effect by increasing the depth of field.

The size of the plurality of optical modules 21 is defined to mean the maximum length between any two points on the edge border of each optical module 21.

In addition, the size of each optical module 21 is determined by projecting each optical module 21 on a plane that includes the center of the pupil 40 and is perpendicular to the straight line between the pupil 40 and the optical module 21. It can be the maximum length between any two points on the edge border of the orthographic projection.

However, if the size is too small, the diffraction phenomenon increases, so it is preferable to make it larger than 0.3 mm, for example.

Additionally, each of the plurality of optical modules 21 may have a circular shape.

Additionally, the optical modules 21 may be formed in an oval shape so that they appear circular when viewed from the pupil 40.

Except for this, other configurations of the optical device 600 are the same as those of the optical device 300 described above, so detailed description will be omitted.

Meanwhile, although not shown, it goes without saying that in the optical devices 400 and 500 of FIGS. 11 to 16, a plurality of second optical elements 20 may be configured as a plurality of pinpoint-shaped optical modules 21.

In the above, the present invention has been described with reference to preferred embodiments of the present invention, but these are illustrative and all changes within the equivalent scope understood by the appended claims and drawings are included in the scope of the present invention. It should be noted that

For example, in the above embodiments, the first optical means 50 and the second optical means 10 may be formed integrally.

In addition, in the above embodiments, it has been described that the virtual image image light inside the second optical means 10 is transmitted to the second optical element 20 through total reflection, but the virtual image light is transmitted to the second optical element 20 without total reflection or through total reflection two or more times. Of course, it can also be transmitted to the optical element 20.

100, 200...conventional optical devices for augmented reality
300, 400, 500, 600...Optical device for eyebox expandable augmented reality using diffractive optical elements
10...second optical means
20...Second optical element
30...Image projection unit
40...pupil
50...First optical means
60...First optical element

Claims (20)

An eyebox expandable augmented reality optical device using a diffractive optical element,
a first optical means through which virtual image image light emitted from the image emitting unit travels;
a first optical element disposed in the first optical means and emitting virtual image light traveling through the inside of the first optical means to the second optical means;
a second optical means for transmitting real object image light emitted from a real object to the pupil of the user's eye, and through which virtual image image light emitted from the first optical element travels; and
A plurality of second optical elements embedded in the second optical means and providing a virtual image to the user by transmitting virtual image light traveling through the second optical means to the pupil of the user's eye.
Including,
The first optical element is a diffractive optical element or a holographic optical element,
The first optical element extends in a first direction and is disposed in the first optical means,
An optical device for augmented reality, wherein the plurality of second optical elements are arranged at intervals in a second direction within the second optical means. In claim 1,
In claim 1,
The first direction is a direction parallel to any one of line segments included in a plane perpendicular to a straight line in the frontal direction from the pupil. In claim 1,
The optical device for augmented reality, characterized in that the second direction is a direction that is not parallel to the first direction. In claim 1,
The optical device for augmented reality, wherein the second direction is perpendicular to the first direction. In claim 1,
Augmented reality, wherein the virtual plane formed by the first direction and the second direction is a two-dimensional plane that can be observed from the user's pupil when the augmented reality optical device is placed in front of the user's pupil. optical device. In claim 5,
The second direction is a direction parallel to any one of line segments perpendicular to the first direction among line segments included in a plane perpendicular to a straight line in the frontal direction from the pupil. In claim 1,
An optical device for augmented reality, wherein an image emitting unit is disposed at one end of the first optical means in the first direction. In claim 1,
The first optical element is an optical device for augmented reality, characterized in that disposed on the upper surface, lower surface, or inside the first optical means. In claim 1,
The first optical element is an optical device for augmented reality, characterized in that it is disposed in the first optical means so as to have an inclination angle with respect to the second direction when viewed from the side with the optical device for augmented reality in front of the pupil. In claim 1,
An optical device for augmented reality, wherein each of the plurality of second optical elements is arranged to be inclined inside the second optical means so as to transmit virtual image light traveling through the inside of the second optical means to the pupil. . In claim 10,
The second optical means has a first surface on which virtual image light and real object image light are emitted toward the user's pupil, and a second surface opposite the first surface and on which real object image light is incident,
The virtual image light emitted from the first optical element is totally reflected by the second surface of the second optical means and is transmitted to a plurality of second optical elements,
The plurality of second optical elements are arranged at an inclination angle inside the second optical means to transmit virtual image light transmitted by total reflection from the second surface of the second optical means to the pupil. Optics for reality. In claim 1,
The optical device for augmented reality, wherein the plurality of second optical elements have a plate shape extending in the first direction. In claim 12,
An optical device for augmented reality, wherein the plurality of second optical elements have a height of 4 mm or less when viewed from the front. In claim 1,
An optical device for augmented reality, wherein each of the plurality of second optical elements is composed of a plurality of optical modules. In claim 14,
Each of the plurality of second optical elements is an optical device for augmented reality, characterized in that it is composed of a plurality of optical modules arranged to be spaced apart from each other and appear in an array form when the optical device for augmented reality is viewed from the front. In claim 14,
An optical device for augmented reality, wherein the size of the plurality of optical modules is 4 mm or less. In claim 1,
An optical device for augmented reality, wherein the plurality of second optical elements are reflection means that reflect incident light. In claim 1,
An optical device for augmented reality, wherein the plurality of second optical elements are half mirrors that transmit part of the incident light and reflect part of the incident light. In claim 1,
An optical device for augmented reality, wherein the plurality of second optical elements are one of a refractive element, a diffractive element, and a holographic optical element, or a combination thereof. In claim 1,
An optical device for augmented reality, wherein the first optical means and the second optical means are integrally formed.

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