Augmented reality head-mounted display system

Abstract

The invention discloses an augmented reality head-mounted display system, which comprises an image source, a coupling-in lens group, an optical fiber, a coupling-out lens group and a grating, wherein the image source emits parallel light, and the parallel light is coupled into the lens group, focused and transmitted in the optical fiber; the optical fiber propagates in the optical fiber in a total reflection manner, is emitted from the output end of the optical fiber, forms parallel light through the coupling-out lens group, enters the grating and is emitted through the grating, so that augmented reality display of an image source image is realized, the optical fiber is arranged around the head, the output end of the optical fiber is arranged above or on two sides of an eye, and the grating is arranged in front of the eye. And the lens group is used for horizontally emitting the parallel light emitted by the coupled-out lens group into human eyes, so that augmented reality display of an image is realized. The augmented reality head-mounted display system only comprises the image source, the coupling-in lens group, the optical fiber, the coupling-out lens group and the grating, the structure is compact, light and thin, and the setting position of the image source can be moved downwards based on the extended optical fiber, so that the power of the image source and the size of a power supply are improved, and the display brightness and time of the system are improved; meanwhile, the display effect is improved by adopting multiple groups of gratings, and the use feeling is further improved.

Description

Technical Field

[0001] The present invention belongs to the field of augmented reality, and in particular relates to an augmented reality head mounted display system. Background Art

[0002] Augmented reality (AR) technology is leading a new round of information technology revolution. It seamlessly integrates virtual information into the real world through images, videos and 3D models, becoming the next detonation point in the information age. In AR technology, optical display solutions play a core role. Currently, the more mature optical display solutions in AR technology are mainly divided into Birdbath (free-form surface) solutions, curved surface reflector solutions, free-form surface prism solutions, geometric array optical waveguide solutions, surface relief grating optical waveguide solutions and volume holographic optical waveguide solutions.

[0003] Combination Figure 1 , Birdbath design in the light ( Figure 1 The blue line in the middle of the image is directed from the display source (the black rectangle perpendicular to the forehead) to a beam splitter at a 45-degree angle. The reflection value (R) and transmission value (T) of this lens (beam splitter) reflect the light at a percentage of R and transmit the rest at the value of T. Both R and T allow the user to see the real world in areas outside the digital image produced by the display. The light from the beam splitter is reflected to the beam combiner, which is a concave mirror that redirects the light to the position of the glasses (the red dotted line in the picture);

[0004] But in a 50 / 50 beam splitter, 50% of the light is lost on the first reflection, and additional light is lost when the light hits the beam combiner. To compensate for the large loss of light, the lenses are usually very dark, similar to wearing sunglasses indoors. The display source is located on the head, and increasing the display brightness will increase power consumption, causing heat and discomfort in the head. When the light source reflects from the inside and outside of the beam combiner, it may cause unwanted images, commonly known as ghosting. The entire display module is too large, and the structure is neither compact nor thin, which will cause a sense of oppression when worn on the head for a long time.

[0005] Combination Figure 2 , the curved reflector solution uses an LCD display source and a curved mirror with reflection / transmission (R / T) values, which is used as a mirror and beam combiner. The light from the display directly hits the concave mirror / combiner and then reflects back to the eye; but because the light only propagates through a single combiner / lens, the light loss is limited to a "single pass" and is much lower than the Birdbath design. The display source is located on the head, and increasing the display brightness will increase power consumption, causing heat and discomfort in the head. The entire display module is too large, and the structure is neither compact nor thin, which will cause a sense of oppression when worn on the head for a long time.

[0006] Combination Figure 3, the free-form prism solution has the light from the display directed to the concave mirror / combiner and reflected back into the eye. The ideal position for the display source is centered and parallel to the mirror. Technically, the ideal position is for the display source to cover the user's eyes, so most designs move the display "off-axis" and place it above the forehead. Off-axis displays on concave mirrors have distortion that needs to be corrected on the software / display side.

[0007] However, in terms of transmittance, the free-form prism solution increases transmittance by 60%, which is higher than the 20% transmittance of the Birdbath solution. The display source is located on the head, and increasing the display brightness will increase power consumption, causing heat and discomfort to the head. The free-form prism is too large and heavy, and the structure is neither compact nor thin. Wearing it on the head for a long time will cause a sense of oppression.

[0008] Combination Figure 4 The geometric array optical waveguide realizes the output of the image and the expansion of the eye box through the stacking of array reflectors, which can achieve a high level of image quality including color and contrast. The light emitted by the image source enters the optical waveguide, and is totally reflected and propagates forward in the optical waveguide. When it encounters the first surface of the array, part of the light is reflected and coupled out from the optical waveguide, and part of the light is transmitted and continues to propagate by total reflection. Until it encounters the second surface of the array, part of the light is reflected and coupled out from the optical waveguide, and part of the light is transmitted and continues to propagate by total reflection, and so on, where the brightness of the light reflected from each array surface is the same.

[0009] The geometric array optical waveguide is thin and light, but has low light efficiency and brightness. The display source is located on the head, and increasing the display brightness will increase power consumption, causing heat and discomfort to the head.

[0010] Combination Figure 5 The surface relief grating optical waveguide solution uses the relief grating to achieve image output and eye box expansion, which can achieve a high level of image quality including color and contrast. The light emitted by the image source is coupled into the optical waveguide through the relief grating, and is totally reflected in the optical waveguide and propagates forward. When encountering the relief grating, the light is coupled out from the relief grating and enters the human eye.

[0011] The surface-embossed grating optical waveguide is thin and light, but has low light efficiency and brightness. The display source is located on the head, and increasing the display brightness will increase power consumption, causing heat and discomfort to the head.

[0012] Combination Figure 6 The volume holographic waveguide uses the volume holographic grating to achieve image output and eye box expansion, which can achieve a high level of image quality including color and contrast. The light emitted by the image source is coupled into the waveguide through the volume holographic grating, and is totally reflected in the waveguide and propagates forward. When encountering the volume holographic grating, the light is coupled out from the volume holographic grating and enters the human eye.

[0013] The volume holographic optical waveguide is thin and light, but has low light efficiency and brightness. The display source is located on the head, and increasing the display brightness will increase power consumption, causing heat and discomfort to the head.

[0014] In summary, the current augmented reality head-mounted display solutions cannot simultaneously take into account the advantages of being light, compact, high brightness, and not feeling oppressive when worn for a long time on the head. Summary of the invention

[0015] In view of the above problems, an object of the present invention is to provide an augmented reality head-mounted display system.

[0016] The specific technical solution for achieving the purpose of the present invention is:

[0017] An augmented reality head mounted display system comprises an image source, an incoupling lens group, an optical fiber, an outcoupling lens group and a grating;

[0018] The image source emits parallel light, which is focused by a coupling lens group and transmitted into the optical fiber;

[0019] The optical fiber propagates by total reflection inside the optical fiber and is emitted from the output end of the optical fiber. After passing through the outcoupling lens group, parallel light is formed and incident on the grating, and then emitted through the grating, realizing the augmented reality display of the image source image.

[0020] Further, the optical fiber is arranged around the head, and its output end is arranged above or on both sides of the eyes;

[0021] The grating is arranged in front of the eye and is used to horizontally incident the parallel light emitted by the outcoupling lens group into the human eye, thereby realizing augmented reality display of the image.

[0022] Furthermore, the grating is a blazed grating or a holographic grating;

[0023] The blazed gratings include multiple groups, each used to reflect light of different wavelengths, and the grating pitch is set according to the wavelength λ of the required reflected light;

[0024] The holographic grating includes multiple groups, each of which is used to reflect light of different wavelengths, and the grating period is set according to the wavelength λ of the required reflected light.

[0025] Furthermore, the inclination angle of the blazed grating to the vertical direction is set to α, and the pitch of the grating is set according to the inclination angle to the vertical direction and the wavelength λ of the required reflected light:

[0026] 2dsinα=λ.

[0027] Furthermore, the pitch of the holographic grating is set according to the incident angle of the incident light beam and the wavelength λ of the desired reflected light:

[0028]

[0029] β out =0

[0030] in, is the angle between the grating vector K of the holographic grating and the vertical direction, β in represents the incident angle of the optical fiber onto the holographic grating, and n represents the refractive index of the grating.

[0031] Furthermore, the focusing angle of the parallel light emitted by the image source is limited to θ max Within:

[0032]

[0033] Wherein, n1 and n2 are the refractive indices of the core and cladding of the optical fiber, respectively, and NA represents the numerical aperture of the optical fiber.

[0034] Furthermore, the coupling lens group includes a plurality of convex lenses and a plurality of concave lenses;

[0035] The multiple convex lenses and the multiple concave lenses are arranged at a certain distance to focus the parallel light emitted by the image source, and spherical or aspherical lenses are used;

[0036] The outcoupling lens group includes a plurality of convex lenses and a plurality of concave lenses;

[0037] The multiple convex lenses and the multiple concave lenses are arranged at a certain distance to adjust the light beam emitted from the output end of the optical fiber into parallel light, and spherical or aspherical lenses are used.

[0038] Furthermore, the light source used by the image source is a three-color laser light source;

[0039] The blazed gratings are provided in three groups, respectively used to reflect red light, green light and blue light;

[0040] The holographic gratings are arranged in three groups, which are used to reflect red light, green light and blue light respectively.

[0041] Furthermore, the optical fiber is arranged around the top of the head, and the output end of the optical fiber is arranged above the human eye.

[0042] Furthermore, the optical fiber is arranged around the side of the head, and the output ends of the optical fiber are arranged on the left and right sides of the human eye.

[0043] Compared with the prior art, the present invention has the following beneficial effects:

[0044] (1) The augmented reality head-mounted display system of the present invention only contains an image source, an input lens group, an optical fiber, an output lens group and a grating. The head display part only contains a blazed grating group or a volume holographic grating group, and does not have an image generation module. The structure is compact and thin, and long-term wearing will not cause pressure on the head and cause discomfort. The image source is large in size and heavy in weight, and long-term wearing around the waist will not cause discomfort. The head-mounted display solution is thin and light, with a compact structure, and long-term wearing of the head will not cause pressure on the head;

[0045] (2) The augmented reality head-mounted display system of the present invention is based on extended optical fibers, and can move the image source from the traditional head to any part of the body, such as the waist. Compared with the traditional head-mounted display solution, the image source of the traditional solution is located at the temple of the glasses, which requires a compact structure, while the image source located at the waist is not limited by the volume, and the brightness of the image source can be improved. Compared with the traditional head-mounted display solution, the maximum eye brightness of the traditional solution is 1000nits, which is sufficient for indoor use. However, on a sunny day with sufficient sunshine, the eye brightness needs to be around 5000nits. Therefore, this brightness can be achieved by increasing the brightness of the image source; in addition, since its volume can be larger, the heat generated by the increased power consumption will not cause discomfort to the head, and a fan can be introduced into the image source to achieve active heat dissipation, which has a better heat dissipation effect, and the fan noise will not affect the discomfort of the head;

[0046] (3) The grating of the augmented reality head-mounted display system of the present invention adopts a blazed grating group or a volume holographic grating group, and adopts a three-layer design for three-color light. Each layer of grating is optimized for one wavelength, which effectively eliminates chromatic aberration and has a good display effect;

[0047] (4) Since the augmented reality head-mounted display system of the present invention can set the image source anywhere on the body, the problem of shortened battery life due to increased brightness can be solved by increasing the battery capacity to further improve the usability.

[0048] The present invention is further described below in conjunction with specific implementation modes. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 It is a schematic diagram of the optical path of the Birdbath solution in the background technology of the present invention.

[0050] Figure 2 It is a schematic diagram of the optical path of the arc-shaped curved reflector solution in the background technology of the present invention.

[0051] Figure 3 It is a schematic diagram of the optical path of the free-form surface prism solution in the background technology of the present invention.

[0052] Figure 4 It is a schematic diagram of the optical path of the geometric array optical waveguide solution in the background technology of the present invention.

[0053] Figure 5 It is a schematic diagram of the optical path of the surface relief grating optical waveguide solution in the background technology of the present invention.

[0054] Figure 6 It is a schematic diagram of the optical path of the volume holographic optical waveguide solution in the background technology of the present invention.

[0055] Figure 7 Schematic diagram of the augmented reality head mounted display system in Example 1 of the present invention.

[0056] Figure 8 This is a top view of the augmented reality head mounted display system solution in Example 1 of the present invention.

[0057] Fig. 9 Schematic diagram of the coupling lens assembly in Example 1 of the present invention.

[0058] Fig.10 Schematic diagram of internal transmission of optical fiber in Example 1 of the present invention.

[0059] Fig.11 Schematic diagram of the outcoupling lens group in Example 1 of the present invention.

[0060] Fig.12 The blazed grating principle used in Example 1 of the present invention Figure 1 .

[0061] Fig.13 The blazed grating principle used in Example 1 of the present invention Figure 2 .

[0062] Fig.14 Schematic diagram of the working state of the blazed grating used in Example 1 of the present invention.

[0063] Fig.15 This is a top view of the augmented reality head mounted display system solution in Example 2 of the present invention.

[0064] Fig.16 It is a side view of the augmented reality head mounted display system solution in Example 2 of the present invention.

[0065] Fig.17 This is a side view of the augmented reality head mounted display system solution in Example 3 of the present invention.

[0066] Fig.18 This is a top view of the augmented reality head mounted display system solution in Example 3 of the present invention.

[0067] Fig.19 This is a schematic diagram of the reflective holographic grating used in Example 4 of the present invention.

[0068] Fig. 20Schematic diagram of the working state of the reflective holographic grating used in Example 4 of the present invention.

[0069] Fig.21 This is a top view of the augmented reality head mounted display system solution in Example 4 of the present invention.

[0070] Fig. 22 This is a side view of the augmented reality head mounted display system solution in Example 4 of the present invention. DETAILED DESCRIPTION

[0071] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the accompanying drawings in the embodiments of the present invention. The described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0072] As shown in this application and claims, unless the context clearly indicates an exception, the words "a", "an", "an kind" and / or "the" do not refer to the singular and may also include the plural. Generally speaking, the terms "include" and "comprise" only indicate the inclusion of the steps and elements that have been clearly identified, and these steps and elements do not constitute an exclusive list. The method or device may also include other steps or elements.

[0073] Unless otherwise specifically stated, the relative arrangement, numerical expressions and numerical values ​​of the parts and steps set forth in these embodiments do not limit the scope of the present application. At the same time, it should be understood that, for ease of description, the sizes of the various parts shown in the accompanying drawings are not drawn according to the actual proportional relationship. The technology, method and equipment known to those of ordinary skill in the relevant field may not be discussed in detail, but in appropriate cases, the technology, method and equipment should be considered as a part of the authorization specification. In all examples shown and discussed here, any specific value should be interpreted as being merely exemplary, rather than as a limitation. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters represent similar items in the following drawings, so that once a certain item is defined in an accompanying drawing, it does not need to be further discussed in subsequent drawings.

[0074] Example 1

[0075] like Figure 7 The side view of the embodiment is shown in FIG. Figure 8 Shown is a top view of the embodiment;

[0076] The parallel light emitted by the image source passes through Fig. 9The coupling lens group shown is focused and propagated into the optical fiber. In this embodiment, the light source used for the image source is a three-color laser light source, because the advantages of the three-color laser light source are good coherence, higher brightness, and wider color gamut.

[0077] The coupling lens group is composed of multiple convex lenses and concave lenses, which are matched at a certain distance. The curvature of the convex and concave surfaces of the convex and concave lenses is determined by design and can be spherical or aspherical. The lens material is a combination of crown glass lens and flint glass lens. The refractive index of crown glass is usually less than 1.6, and the dispersion coefficient (also known as Abbe number, the larger the value, the smaller the dispersion) is greater than 50. The opposite is true for flint glass. By using crown glass lens and flint glass lens together, the imaging quality can be improved and chromatic aberration can be eliminated. The coupling lens group can also be composed of aspherical lenses made of plastic materials (such as acrylic), which can also improve the imaging quality and eliminate chromatic aberration.

[0078] In this embodiment, a coupling lens group consisting of 6 lenses is used. In actual use, 3 to more lenses can be used according to design requirements while ensuring imaging quality;

[0079] The focusing angle of the parallel light lens coupled into the lens group needs to meet the numerical aperture angle of the optical fiber. The schematic diagram of the light beam propagation inside the optical fiber is as follows Fig.10 As shown;

[0080] Optical fiber is composed of two homogeneous media, the inner one is called the core, and the outer one surrounding the core is called the cladding. The function of the cladding is to reduce loss and protect the core. Their refractive indices are n1 and n2, respectively, and n1>n2;

[0081] The light beam is transmitted in the fiber core. The light is emitted from the fiber core to the interface of the cladding. The incident angle is greater than the critical angle θ. c =arcsin(n2 / n1) total reflection occurs, so the light is confined in the core and propagates forward along the broken line. When light is injected into the optical fiber, in order to reduce coupling loss, the core should receive as much incident light as possible. The parameter that determines the core coupling efficiency is the numerical aperture NA of the optical fiber. The numerical aperture NA describes the end face of the optical fiber. Only light within a certain taper range can enter the core, and light outside the taper range is absorbed by the cladding. This type of light is lost because it is all refracted toward the cladding after reaching the core / cladding interface, and is not reflected back to the core. The difference between the refractive index n1 of the optical fiber core and the refractive index n2 of the cladding determines the maximum receiving angle of the optical fiber to light, which also determines the numerical aperture NA of the optical fiber. Therefore, the half-angle of the focusing angle of the parallel light emitted by the image source after the coupling lens group is less than θ max , that is, limited to θ max Within:

[0082]

[0083] The light from the image source is totally reflected and propagated in the optical fiber. In this embodiment, the optical fiber is wound around the top of the head, and the output end of the optical fiber is above the human eye. The light is emitted from the output end of the optical fiber at a numerical aperture angle θ and becomes parallel light after passing through the coupling lens group.

[0084] The outcoupling lens assembly of this embodiment is as follows: Fig.11 As shown, its design is opposite to that of the coupling-in lens group. The coupling-out lens group is also composed of multiple convex lenses and concave lenses arranged at a certain distance. The curvatures of the convex and concave surfaces of the convex and concave lenses are determined by design and can be spherical or aspherical. The lens material is a combination of crown glass lens and flint glass lens. The coupling-out lens group can also be composed of aspherical lenses made of plastic material (such as acrylic). In this embodiment, a coupling-out lens group composed of 6 lenses is used. In actual use, 3 to more lenses can be used according to design requirements while ensuring imaging quality.

[0085] The parallel light emitted from the lens group is incident on the blazed grating. The working principle of the blazed grating is as follows: Fig.12 and 13 As shown in the figure, when the grating is engraved into a sawtooth groove section, the light energy of the grating is concentrated in a predetermined direction, that is, on a certain spectral level. When detecting from this direction, the intensity of the spectrum is the largest. This phenomenon is called blazing, and this grating is called a blazed grating; one illumination method of a blazed grating is that when parallel light is incident perpendicular to the groove surface, the optical path difference condition of the maximum inter-slit interference is satisfied in the direction of the zero-order extreme intensity of the unit diffraction. At this time, the zero-order maximum direction of the unit diffraction is along the direction perpendicular to the groove surface, and the first-order spectrum near the wavelength λ that satisfies the following condition is blazed.

[0086] 2dsinα=λ

[0087] Applications of this blazed grating include Fig.13 As shown, the blazed grating needs to form a certain inclination angle with the vertical direction, the inclination angle is α, so that the direction of the outgoing light is horizontal and enters the human eye. The human eye believes that the light is propagated in a straight line, so the human eye looks against the light and can see the virtual image in front of it. The virtual image can be integrated with the surrounding environment, thereby achieving the effect of augmented reality display.

[0088] The blazed grating of this embodiment comprises three layers, the first blazed grating acts on red light and transmits green light and blue light, the second blazed grating acts on green light and transmits blue light, and the third blazed grating acts on blue light. The wavelength λ of each blazed grating is different, but the angles of the incident light and the outgoing light are the same, so the grating pitch d is also different. The blazed grating group can make light of different wavelengths incident and emitted in the same direction, thereby solving the dispersion problem of the three-color light.

[0089] Example 2

[0090] like Fig.15 FIG. 1 is a top view of the embodiment of the present invention. Fig.16 The figure shows a side view of the scheme of this embodiment. Different from the first embodiment, the optical fiber of this scheme is arranged around the side of the head, and the output end of the optical fiber is on the left and right sides of the human eye. The light is emitted from the output end of the optical fiber at a numerical aperture angle θ max The light is emitted and becomes parallel light after passing through the outcoupling lens group.

[0091] Example 3

[0092] like Fig.17 The side view of the embodiment is shown in FIG. Fig.18 The figure shows a top view of the scheme of this embodiment; similar to the embodiment 1, the optical fiber in this embodiment is wound around the top of the head, and the output end of the optical fiber is above the human eye;

[0093] The difference between this embodiment and embodiment 1 is that the grating used in this embodiment is a reflective volume holographic grating:

[0094] The parallel light emitted from the lens group is incident on the reflective volume holographic grating. The working principle of the reflective volume holographic grating is as follows: Fig.19 As shown in the figure, its diffraction characteristic is that the incident light and the diffracted light are on the same side of the grating. In the preparation of the reflective volume holographic grating, the object light and the reference light are respectively incident from the two sides of the recording medium to interfere. In terms of diffraction characteristics, the reflective volume holographic grating can eliminate the remaining diffraction orders except the +1 order under a specific combination of incident angle, wavelength, grating period, and grating inclination angle, that is, the diffraction energy is almost entirely concentrated in the +1 order. Assuming that the equivalent refractive index of the recording medium is n, the optical expression of the reflective volume holographic grating can be expressed as:

[0095]

[0096] Based on the characteristics of reflective volume holographic grating and satisfying

[0097]

[0098] Where n is the grating refractive index, is the angle between the grating vector K and the y-axis. Based on the angle positive and negative rule, we stipulate With the incident angle θ in The same sign is on the same side of the y-axis, and the opposite sign is on the opposite side; the grating period is d, where λ is the wavelength of the incident light beam in air;

[0099] The geometric relationship between the incident light and the +1-order diffracted light can be regarded as a mirror reflection on the grating plane with the grating vector K as the normal. This geometric relationship can be used to easily determine the angular relationship between the incident light and the diffracted light. We need the outgoing light direction β outThe reflective volume holographic grating is 0. Compared with the blazed grating, the reflective volume holographic grating is vertical. It does not need to form a certain inclination angle, so that the direction of the emitted light is horizontal to enter the human eye. The human eye believes that the light propagates in a straight line, so the human eye can see the virtual image in front of it when looking against the light. The virtual image can be integrated with the surrounding environment, thereby achieving the effect of augmented reality display.

[0100] The working state of the reflective volume holographic grating group used in this embodiment is as follows: Fig. 22 As shown, the reflective volume holographic grating group includes three layers of reflective volume holographic gratings, the first layer of reflective volume holographic grating acts on red light and transmits green light and blue light, the second layer of reflective volume holographic grating acts on green light and transmits blue light, and the third layer of reflective volume holographic grating acts on blue light. The wavelength λ of each layer of reflective volume holographic grating is different, but the angles of incident light and outgoing light are the same, so the grating period d is different. The reflective volume holographic grating group can make light of different wavelengths incident and emitted in the same direction, thereby solving the dispersion problem of three-color light.

[0101] Example 4

[0102] like Fig.21 FIG. 1 is a top view of the embodiment of the present invention. Fig. 22 The figure shows a side view of the embodiment.

[0103] Similar to Example 3, the grating used in this embodiment is a reflective volume holographic grating, but different from Example 3, in this embodiment, the optical fiber is wound around the side of the head, and the output ends of the optical fiber are on the left and right sides of the human eye.

[0104] Through the introduction of the above embodiments, it can be seen that the solution of the present invention has a simple structure. Compared with the traditional solution, the display component of the head is only a coupling lens group and a grating, and the optical fiber can be arranged in the head in a variety of ways, which is flexible to use.

[0105] In addition, based on the extended optical fiber, this solution can move the image source from the traditional head to any part of the body, such as the waist. Compared with the traditional head-mounted display solution, the image source of the traditional solution is located at the temple of the glasses, which requires a compact structure, while being located at the waist is not restricted by volume. The brightness of the image source can be improved, and the volume restriction is reduced, thereby increasing the power setting of the image source and solving the resulting power supply problem. Similarly, the heat dissipation problem can also be solved by adding an additional fan.

[0106] In summary, compared with traditional solutions, the solution of the present invention has a simple structure, a light and thin display solution, a compact structure, and no pressure on the head when worn for a long time. At the same time, it has a good display effect and a longer battery life. The user experience is greatly improved compared to the existing solutions, and it has a very high application prospect.

[0107] The above-mentioned embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application shall be subject to the attached claims.

Claims

1. An augmented reality head mounted display system, characterized in that: It includes an image source, a coupling lens group, an optical fiber, a coupling lens group and a grating; The image source emits parallel light, which is focused by a coupling lens group and transmitted into the optical fiber; The optical fiber propagates by total reflection inside the optical fiber and is emitted from the output end of the optical fiber. After passing through the outcoupling lens group, parallel light is formed and incident on the grating, and then emitted through the grating, realizing the augmented reality display of the image source image.

2. The augmented reality head mounted display system according to claim 1, characterized in that: The optical fiber is arranged around the head, and the output end thereof is arranged above or on both sides of the eye; The grating is arranged in front of the eye and is used to horizontally incident the parallel light emitted by the outcoupling lens group into the human eye, thereby realizing augmented reality display of the image.

3. The augmented reality head mounted display system according to claim 2, characterized in that: The grating is a blazed grating or a holographic grating; The blazed gratings include multiple groups, each used to reflect light of different wavelengths, and the grating pitch is set according to the wavelength λ of the required reflected light; The holographic grating includes multiple groups, each of which is used to reflect light of different wavelengths, and the grating period is set according to the wavelength λ of the required reflected light.

4. The augmented reality head mounted display system according to claim 3, characterized in that: The inclination angle of the blazed grating with respect to the vertical direction is set to α, and the pitch of the grating is set according to the inclination angle with respect to the vertical direction and the wavelength λ of the required reflected light: 2dsinα=λ.

5. The augmented reality head mounted display system according to claim 3, characterized in that: The grating pitch of the holographic grating is set according to the incident angle of the incident light beam and the wavelength λ of the desired reflected light: β out ＝0 in, is the angle between the grating vector K of the holographic grating and the vertical direction, β in represents the incident angle of the optical fiber onto the holographic grating, and n represents the refractive index of the grating.

6. The augmented reality head mounted display system according to claim 2, characterized in that: The parallel light emitted by the image source is limited to a focusing angle of θ after being coupled into the lens group. max Within: Wherein, n1 and n2 are the refractive indices of the core and cladding of the optical fiber, respectively, and NA represents the numerical aperture of the optical fiber.

7. The augmented reality head mounted display system according to claim 1, characterized in that: The coupling lens group includes a plurality of convex lenses and a plurality of concave lenses; The multiple convex lenses and the multiple concave lenses are arranged at a certain distance to focus the parallel light emitted by the image source, and spherical or aspherical lenses are used; The outcoupling lens group includes a plurality of convex lenses and a plurality of concave lenses; The multiple convex lenses and the multiple concave lenses are arranged at a certain distance to adjust the light beam emitted from the output end of the optical fiber into parallel light, and spherical or aspherical lenses are used.

8. The augmented reality head mounted display system according to claim 3, characterized in that: The light source used by the image source is a three-color laser light source; The blazed gratings are provided in three groups, respectively used to reflect red light, green light and blue light; The holographic gratings are arranged in three groups, which are used to reflect red light, green light and blue light respectively.

9. The augmented reality head mounted display system according to claim 2, characterized in that: The optical fiber is arranged around the top of the head, and the output end of the optical fiber is arranged above the human eye.

10. The augmented reality head mounted display system according to claim 2, characterized in that: The optical fiber is arranged around the side of the head, and the output ends of the optical fiber are arranged on the left and right sides of the human eye.

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