Binocular fusion color waveguide display system and smart wearable device

Abstract

This invention proposes a binocular fusion-based color waveguide display system, relating to the field of smart wearable device technology. The system includes a first display system and a second display system. The first display system includes a first transmission channel; the second display system includes a second transmission channel. Light of different wavelengths is transmitted through the first and second transmission channels, ultimately synthesizing a color image at the human eye. The brightness, hue, and virtual image depth information of the images transmitted by the first and second transmission channels differ. This invention utilizes left and right eye waveguide display systems to transmit multiple colors through separate channels. Under certain binocular brightness difference stimulation, binocular virtual image depth information difference, and binocular hue difference stimulation, virtual images of different colors reaching the human eye through total internal reflection in the waveguide are superimposed, thereby achieving a color display effect.

Description

Technical Field

[0001] This invention relates to the field of smart wearable device technology, and in particular to a binocular fusion color waveguide display system and a smart wearable device. Background Technology

[0002] In recent years, with the development of AR and VR technologies, AR / VR glasses have begun to be used in industrial fields. Many researchers have been studying a holographic waveguide structure. For image transmission using a planar waveguide, certain conditions must be met. When the input light source has a certain angle, the light rays at the left edge need to satisfy the total internal reflection condition, and the light rays at the right edge need to enter the waveguide. Furthermore, for imaging performance, the exit pupil continuity constraint must be met.

[0003] For a holographic optical waveguide, the horizontal field of view (FOV) can be derived from the first-order grating equation:

[0004]

[0005] Among them, Λ x It is the transverse period of a polarizing volume holographic grating (PVG), θ i It is the angle of incidence in the incident medium, θ d The diffraction angle of the exit medium, n i It is the refractive index of the incident medium, which in this case refers to air, n g λ is the refractive index of the exit medium, specifically the waveguide refractive index, and λ is the wavelength in vacuum. Combining the formula above, to prevent dispersion, gratings within the same glass layer need to maintain the same transverse period. Furthermore, different wavelengths of light have different diffraction angles, resulting in different FOVs for different wavelengths of light.

[0006] To better and more intuitively analyze the horizontal field of view limit, we can use... Figure 1 K-space analysis. If a single-layer waveguide is used to achieve colorization (multiple gratings can be superimposed on the single-layer waveguide), the K-vector diagram shows that the left half of the field of view for blue light is limited by total internal reflection of the waveguide, and the right half of the field of view for red light is limited by continuity. Therefore, the observable color field of view (FOV) is very small (RGB), and there is severe chromatic dispersion. Therefore, the best method is to use three-layer waveguides to transmit all three colors, which can achieve the FOV of green light as shown in the figure. However, this method involves a relatively large thickness.

[0007] In summary, while existing holographic waveguide display solutions can expand the field of view for colorization by employing multi-layer waveguide transmission optical paths, this inevitably increases the size and weight of the waveguide system. Furthermore, the theoretical limit of the colorization FOV for a single-layer waveguide still cannot meet the requirements for a large field of view, and it suffers from severe chromatic dispersion problems, which require further solutions. Summary of the Invention

[0008] To address the aforementioned technical problems, this invention proposes a binocular fusion-based color waveguide display system.

[0009] The first aspect of this invention discloses a binocular fusion-based colorized waveguide display system. The colorized waveguide display system includes: a first display system and a second display system;

[0010] The first display system includes a first transmission channel; the second display system includes a second transmission channel;

[0011] Light of different wavelengths is transmitted through the first and second transmission channels, and finally a color image is synthesized at the human eye; however, the brightness, hue, and virtual image depth information of the images transmitted by the first and second transmission channels differ.

[0012] Optionally, the first display system includes a first waveguide substrate, at least one first coupling grating, and a corresponding number of first coupling gratings; the second display system includes a second waveguide substrate, at least two second coupling gratings, and a corresponding number of second coupling gratings; one coupling grating and one corresponding coupling grating are responsible for diffracting light of a single wavelength;

[0013] At least one first coupling grating and a corresponding number of first coupling gratings are fixedly disposed on the first waveguide substrate. After a virtual image with a certain FOV enters the first waveguide substrate, it is diffracted by at least one first coupling grating and enters the first waveguide substrate for total internal reflection. After reaching the first coupling grating, the beam with a certain FOV is transmitted to the human eye.

[0014] At least two second coupling gratings and a corresponding number of second coupling gratings are fixedly disposed on the second waveguide substrate. After a virtual image with a certain FOV enters the second waveguide substrate, it is diffracted by at least two second coupling gratings and enters the second waveguide substrate for total internal reflection. After reaching the corresponding second coupling grating, the beam with a certain FOV is transmitted to the human eye.

[0015] Optionally, the first display system and the second display system share a third waveguide substrate; the first display system further includes at least one first coupling grating and a corresponding number of first coupling gratings; the second display system further includes at least two second coupling gratings and a corresponding number of second coupling gratings; one coupling grating and one corresponding coupling grating are responsible for diffracting light of a single wavelength;

[0016] At least one first coupling grating and a corresponding number of first coupling gratings are fixedly disposed on the third waveguide substrate. After a virtual image with a certain FOV enters the third waveguide substrate, it is diffracted by at least one first coupling grating and enters the third waveguide substrate for total internal reflection. After reaching the first coupling grating, the beam with a certain FOV is transmitted to the human eye.

[0017] At least two second coupling gratings and a corresponding number of second coupling gratings are fixedly disposed on the third waveguide substrate. After a virtual image with a certain FOV enters the third waveguide substrate, it is diffracted by at least two second coupling gratings and enters the third waveguide substrate for total internal reflection. After reaching the corresponding second coupling grating, the beam with a certain FOV is transmitted to the human eye.

[0018] Optionally, the number of first coupling gratings is one, two, or three; the number of second coupling gratings is two or three.

[0019] Optionally, when there are two first coupling gratings and two second coupling gratings, one first coupling grating and one first coupling grating are responsible for the field of view (FOV) of the first wavelength light, and the other first coupling grating and the other first coupling grating are responsible for the complete field of view (FOV) of the second wavelength light.

[0020] A second input grating and a second output grating are responsible for the negative field of view (FOV) of diffracting the first wavelength light, while another second input grating and another second output grating are responsible for the complete FOV of diffracting the third wavelength light.

[0021] Optionally, at least one first coupling-in grating and a corresponding number of first coupling-out gratings have the same transverse period Λ. x1 At least two second-coupled gratings and a corresponding number of second-coupled-out gratings have the same transverse period Λ. x2 .

[0022] Optionally, the coupling grating and the coupling grating are one of the following: surface relief grating, volume holographic grating, or liquid crystal polarizer grating.

[0023] Optionally, the coupling grating and the coupling grating are reflective liquid crystal polarizer gratings or transmissive liquid crystal polarizer gratings.

[0024] Optionally, the difference in display brightness between the first display system and the second display system is less than 20%, and the difference in transmission wavelength between the first display system and the second display system is within 100nm.

[0025] A second aspect of the present invention discloses a smart wearable device, including the binocular fusion color waveguide display system described in any of the preceding claims.

[0026] In summary, the solution proposed in this invention has the following technical effects: Compared with existing methods, this invention transmits multiple colors through separate channels using a waveguide display system for both left and right eyes. Under certain conditions of binocular brightness difference stimulation, binocular virtual image depth information difference, and binocular hue difference stimulation, virtual images of different colors that reach the human eye through total internal reflection of the waveguide are superimposed to achieve a color display effect. Attached Figure Description

[0027] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0028] Figure 1 K-vector diagram of a scheme for colorizing a single-layer waveguide provided by existing technology;

[0029] Figure 2 This is a structural diagram of the binocular fusion color waveguide display system according to Embodiment 1 of the present invention;

[0030] Figure 3 A schematic diagram of the grating structure and diffraction characteristics of a liquid crystal polarizer grating;

[0031] Figure 4 This is the k-space diagram corresponding to the waveguide display system of Embodiment 1 of the present invention;

[0032] Figure 5 This is a structural diagram of the binocular fusion color waveguide display system according to Embodiment 2 of the present invention;

[0033] Figure 6 This is a structural diagram of the binocular fusion color waveguide display system of Embodiment 3 of the present invention.

[0034] Explanation of icon numbers in the instruction manual

[0035] 100 - First optical engine; 101 - Second optical engine; 102 - First waveguide substrate; 103 - Second waveguide substrate; 104 - Human eye; 105 - First coupling grating; 106 - Second coupling grating; 107 - First coupling grating; 108 - Second coupling grating; 109 - Third coupling grating; 110 - Fourth coupling grating; 111 - Third coupling grating; 112 - Fourth coupling grating;

[0036] 200 - Third optical engine; 201 - Third waveguide substrate; 202 / 301 - Left eye first coupling grating; 203 / 302 - Left eye second coupling grating; 204 / 303 - Right eye first coupling grating; 205 - Right eye second coupling grating; 206 / 304 - Left eye first output grating; 207 / 305 - Left eye second output grating; 208 / 306 - Right eye first output grating; 209 - Right eye second output grating; 210 - Left eye; 211 - Right eye. Detailed Implementation

[0037] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0038] Because it is difficult to achieve a large color field of view (FOV) with a single-layer waveguide. RGB At the same time, achieve a large FOV RGB The need for multi-layered waveguide transmission substrates makes it impossible to simultaneously achieve both thinness and color performance, thus requiring optimized solutions to expand the color field of view (FOV). This invention proposes a method to enhance the color FOV by fusing different color channels using binocular vision, achieving a large field of view color FOV for binocular vision with only one layer.

[0039] The first aspect of this invention discloses a binocular fusion-based colorized waveguide display system. The colorized waveguide display system includes: a first display system and a second display system.

[0040] The first display system includes a first transmission channel; the second display system includes a second transmission channel. Light of different wavelengths is transmitted through the first and second transmission channels, and a color image is finally synthesized at the human eye; wherein, the brightness, hue, and virtual image depth information of the images transmitted by the first and second transmission channels differ.

[0041] Optionally, the first display system includes a first waveguide substrate, at least one first coupling grating, and a corresponding number of first coupling gratings; the second display system includes a second waveguide substrate, at least two second coupling gratings, and a corresponding number of second coupling gratings; one coupling grating and one corresponding coupling grating are responsible for diffracting light of a single wavelength;

[0042] At least one first coupling grating and a corresponding number of first coupling gratings are fixedly disposed on the first waveguide substrate. After a virtual image with a certain FOV enters the first waveguide substrate, it is diffracted by at least one first coupling grating and enters the first waveguide substrate for total internal reflection. After reaching the first coupling grating, the beam with a certain FOV is transmitted to the human eye.

[0043] At least two second coupling gratings and a corresponding number of second coupling gratings are fixedly disposed on the second waveguide substrate. After a virtual image with a certain FOV enters the second waveguide substrate, it is diffracted by at least two second coupling gratings and enters the second waveguide substrate for total internal reflection. After reaching the corresponding second coupling grating, the beam with a certain FOV is transmitted to the human eye.

[0044] Optionally, the number of first coupling gratings is one, two, or three; the number of second coupling gratings is two or three.

[0045] Optionally, when there are two first coupling gratings and two second coupling gratings, one first coupling grating and one first coupling grating are responsible for the field of view (FOV) of the first wavelength light, and the other first coupling grating and the other first coupling grating are responsible for the complete field of view (FOV) of the second wavelength light.

[0046] A second input grating and a second output grating are responsible for the negative field of view (FOV) of diffracting the first wavelength light, while another second input grating and another second output grating are responsible for the complete FOV of diffracting the third wavelength light.

[0047] Optionally, at least one first coupling-in grating and a corresponding number of first coupling-out gratings have the same transverse period Λ. x1 At least two second-coupled gratings and a corresponding number of second-coupled-out gratings have the same transverse period Λ. x2 .

[0048] Optionally, the coupling grating and the coupling grating are one of the following: surface relief grating, volume holographic grating, or liquid crystal polarizer grating.

[0049] Optionally, the coupling grating and the coupling grating are reflective liquid crystal polarizer gratings or transmissive liquid crystal polarizer gratings.

[0050] Optionally, the difference in display brightness between the first display system and the second display system is less than 20%, and the difference in transmission wavelength between the first display system and the second display system is within 100nm.

[0051] Example 1:

[0052] This invention proposes a method for binocular fusion to amplify FOVRGB. Figure 2The structure of the system is shown. For the left eye, a virtual image with a certain field of view (FOV) is emitted by the first light engine 100 and enters the first waveguide substrate 102. It is then diffracted into the waveguide by the first coupling grating 105 and the second coupling grating 106 for total internal reflection. After reaching the first coupling grating 107 and the second coupling grating 108, the beam of light with a certain FOV is transmitted to the human eye 104, allowing the human eye to see the virtual image clearly at a certain distance. Among them, the first coupling grating 105 and the first coupling grating 107 are responsible for the FOV of the front field of view of the green light, and the second coupling grating 106 and the second coupling grating 108 are responsible for the complete FOV of the red light. For the right eye, a virtual image with a certain field of view (FOV) is emitted by the second light engine 101 and enters the planar waveguide substrate 103. It is then diffracted into the waveguide by the third coupling grating 111 and the fourth coupling grating 112 for total internal reflection. After reaching the third coupling grating 109 and the fourth coupling grating 110, the beam with a certain FOV is transmitted to the human eye 104, allowing the human eye to see the virtual image clearly at a certain distance. Specifically, the third coupling grating 111 and the third coupling grating 109 are responsible for the negative field of view (FOV) of the green light diffracted, while the fourth coupling grating 112 and the fourth coupling grating 110 are responsible for the complete FOV of the blue light diffracted.

[0053] Furthermore, the first light engine 100 and the second light engine 101 can be micro-display projection optical engines such as LCoS, Micro-LED, Micro-OLED, and DLP. The coupling gratings and coupling gratings used can be reflective or transmissive gratings and are attached to the surfaces of the first waveguide substrate 102 and the planar waveguide substrate 103. The gratings can be surface relief gratings, volume holographic gratings, or liquid crystal polarizer gratings (PVG). In this embodiment, a liquid crystal polarizer grating is used, and its grating structure and diffraction characteristics are as follows... Figure 3 (a) PVG utilizes the periodic change in refractive index caused by the variation of the optical axis of LC (liquid crystal) in three-dimensional space. Here, Λx is the period of sinusoidal rotation of the liquid crystal molecules in the x-direction, Λy represents the spacing between isotropic surfaces in the y-direction, P represents the spacing of the liquid crystal molecules rotating 360° along their optical axis, Λb is the Bragg period of PVG, which is half the size of P, and φ is the tilt angle of the Bragg plane. Their relationships can be derived from each other using trigonometric functions. Due to the helical chirality of CLC, PVG exhibits polarization-selective diffraction characteristics. Specifically, for incident light with different polarization states, PVG can selectively diffract, and the polarization state of the diffracted beam will change accordingly. For example... Figure 3 As shown in (b), a right-handed reflective PVG will reflect right-handed circularly polarized light (RCP), while left-handed circularly polarized light will pass through (LCP); a left-handed transmissive PVG will diffract LCP and convert the polarization state to RCP, and the incident RCP will pass through directly. In this embodiment, the gratings all use left-handed PVGs.

[0054] Light of different wavelengths is transmitted through the left and right eye channels, ultimately resulting in a synthesized color image observed by the human eye. Regarding the quality of the color image, color competition can easily occur, leading to a non-color image; color perception is related to visual stimulation. After multiple adjustments, good color effects were achieved when the binocular brightness difference was below 20%, the depth information difference was small, and the binocular wavelength difference was within 100nm. The binocular brightness difference can be controlled by adjusting the light output of the optical engine or the diffraction efficiency of the grating through simulation design; the same applies to the binocular wavelength difference. Furthermore, in K-space, the achievable color FOV range is as follows... Figure 4 As shown. In k-space, all possible light propagation directions form a circular region, and the grating performs a certain vector displacement on the light rays in k-space. For example... Figure 4 As shown, the refractive index of air is 1, is the radius of the inner circle in k-space, the refractive index of the waveguide is , and is the radius of the outer circle in k-space. The yellow area of ​​the ring represents the field of view that the waveguide can transmit, and and represent the x and y components of the normalized wave vector. Typically, the incident field of view is centrally symmetric, and the horizontal FOV can be expressed as follows through a series of vector calculations:

[0055]

[0056] The designed grating period can be defined by the grating vector shift as follows:

[0057]

[0058] To prevent chromatic aberration and facilitate binocular image convergence, in Embodiment 1, the first insertion grating 105, the second insertion grating 106, the first output grating 107, and the second output grating 108 of the left eye must maintain a consistent lateral period Λx1. Similarly, the third insertion grating 111, the fourth insertion grating 112, the third output grating 109, and the fourth output grating 110 of the right eye must maintain a consistent lateral period Λx2. The lateral period Λx1 of the left eye can be obtained by substituting red light into equation (2), and the lateral period Λx2 of the right eye can be obtained by substituting blue light into equation (2).

[0059] Optionally, the first display system and the second display system share a third waveguide substrate; the first display system further includes at least one first coupling grating and a corresponding number of first coupling gratings; the second display system further includes at least two second coupling gratings and a corresponding number of second coupling gratings; one coupling grating and one corresponding coupling grating are responsible for diffracting light of a single wavelength;

[0060] At least one first coupling grating and a corresponding number of first coupling gratings are fixedly disposed on the third waveguide substrate. After a virtual image with a certain FOV enters the third waveguide substrate, it is diffracted by at least one first coupling grating and enters the third waveguide substrate for total internal reflection. After reaching the first coupling grating, the beam with a certain FOV is transmitted to the human eye.

[0061] At least two second coupling gratings and a corresponding number of second coupling gratings are fixedly disposed on the third waveguide substrate. After a virtual image with a certain FOV enters the third waveguide substrate, it is diffracted by at least two second coupling gratings and enters the third waveguide substrate for total internal reflection. After reaching the corresponding second coupling grating, the beam with a certain FOV is transmitted to the human eye.

[0062] Example 2:

[0063] The difference from Example 1 is that, as Figure 5 As shown, a binocular color waveguide display system is achieved by using only a single optical engine (third optical engine 200) and utilizing the polarization selectivity of PVG. Specifically, the left eye first coupling grating 202, the left eye second coupling grating 203, the right eye first coupling grating 204, and the right eye second coupling grating 205 are stacked on the third waveguide substrate 201, and the lateral period of the left eye first coupling grating 202 and the left eye second coupling grating 203 is different from that of the right eye first coupling grating 204 and the right eye second coupling grating 205. Linearly polarized light with a certain field of view (FOV) of RGB colors emitted by the third light engine 200 enters the waveguide substrate 201. The left eye's first coupling grating 202 and second coupling grating 203 transmit the complete field of view for diffracting red light and the positive portion of the field of view for diffracting green light into the third waveguide substrate 201 for total internal reflection. The right eye's first coupling grating 204 and second coupling grating 205 transmit the complete field of view for diffracting blue light and the negative portion of the field of view for diffracting green light into the waveguide substrate 201 for total internal reflection. The left eye's first output grating 206 and second output grating 207 transmit the complete field of view of red light and the positive portion of the field of view of green light to the left eye 210, and the right eye's first output grating 208 and second output grating 209 transmit the complete field of view of blue light and the negative portion of the field of view of green light to the right eye 211. Regarding the polarization selectivity of the gratings, in this embodiment, a PVG responsive to LCP is used to respond to the left target grating, and a PVG responsive to RCP is used to respond to the right target grating. The achievable color FOV is in k-space with... Figure 4 Same as above.

[0064] Example 3:

[0065] The difference from Example 2 is that, as Figure 6As shown, the right eye channel transmits one color (e.g., green), and the left eye channel transmits two other colors (e.g., red and blue). Specifically, the left eye first coupling grating 301, the left eye second coupling grating 302, and the right eye first coupling grating 303 are stacked on the third waveguide substrate 201, and the lateral period of the left eye first coupling grating 301 and the left eye second coupling grating 302 is different from the lateral period of the right eye first coupling grating 3035. After the linearly polarized light with a certain FOV of RGB emitted by the third light engine 200 enters the waveguide substrate 201, the left eye first coupling grating 301 and the left eye second coupling grating 302 bring the complete field of view of red light and the complete field of view of blue light, which are responsible for diffracting red light, into the third waveguide substrate 201 for total internal reflection, while the right eye first coupling grating 303 brings the complete field of view of green light, which is responsible for diffracting green light, into the waveguide substrate 201 for total internal reflection. The left eye's first output grating 304 and second output grating 305 transmit the complete field of view of red light and blue light to the left eye 210, respectively, while the right eye's first output grating 306 transmits the complete field of view of green light to the right eye 211. Regarding the polarization selectivity of the gratings, in this embodiment, the grating responding to the left eye uses a PVG responsive to LCP, and the grating responding to the right eye uses a PVG responsive to RCP. The achievable color FOV in k-space is... Figure 4 Same as above.

[0066] It should be noted that binocular fusion can be achieved using either a single-beam engine or a multi-beam engine. A dual-beam engine can be used with one waveguide substrate for each eye, while a single-beam engine can be used at the center of the human eye or at the edge of a single eye. Furthermore, the grating used is a polarization-selective device.

[0067] The colors of the images transmitted by the left and right eyes can be freely combined. The displayed color FOV and color fusion effect are related to the combination method, and are not limited to the left eye transmitting red and green light and the right eye transmitting blue and green light.

[0068] A second aspect of the present invention discloses a smart wearable device, including the binocular fusion color waveguide display system described in any of the preceding claims.

[0069] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein, and such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A binocular fusion-based color waveguide display system, characterized in that, The colorized waveguide display system includes: a first display system and a second display system; The first display system includes a first transmission channel; the second display system includes a second transmission channel; Light of different wavelengths is transmitted through the first and second transmission channels, and finally a color image is synthesized at the human eye; however, the tonal information of the images transmitted by the first and second transmission channels differs. By adjusting the light output of the light engine and / or the diffraction efficiency of the grating, the difference in display brightness between the first display system and the second display system is less than 20%. The grating period used in the first display system is determined according to the first wavelength, and the grating period used in the second display system is determined according to the second wavelength. The first wavelength and the second wavelength are different, so that the difference in transmission wavelength between the first display system and the second display system is within 100nm. The first display system includes a first waveguide substrate, at least one first coupling grating, and a corresponding number of first coupling gratings; the second display system includes a second waveguide substrate, at least two second coupling gratings, and a corresponding number of second coupling gratings; one coupling grating and one corresponding coupling grating are responsible for diffracting light of a single wavelength; At least one first coupling grating and a corresponding number of first coupling gratings are fixedly disposed on the first waveguide substrate. After a virtual image with a certain FOV enters the first waveguide substrate, it is diffracted by at least one first coupling grating and enters the first waveguide substrate for total internal reflection. After reaching the first coupling grating, the beam with a certain FOV is transmitted to the human eye. At least two second coupling gratings and a corresponding number of second coupling gratings are fixedly disposed on the second waveguide substrate. After a virtual image with a certain FOV enters the second waveguide substrate, it is diffracted by at least two second coupling gratings and enters the second waveguide substrate for total internal reflection. After reaching the corresponding second coupling grating, the beam with a certain FOV is transmitted to the human eye. The first display system and the second display system share a third waveguide substrate; the first display system further includes at least one first coupling grating and a corresponding number of first coupling gratings; the second display system further includes at least two second coupling gratings and a corresponding number of second coupling gratings; one coupling grating and one corresponding coupling grating are responsible for diffracting light of a single wavelength; At least one first coupling grating and a corresponding number of first coupling gratings are fixedly disposed on the third waveguide substrate. After a virtual image with a certain FOV enters the third waveguide substrate, it is diffracted by at least one first coupling grating and enters the third waveguide substrate for total internal reflection. After reaching the first coupling grating, the beam with a certain FOV is transmitted to the human eye. At least two second coupling gratings and a corresponding number of second coupling gratings are fixedly disposed on the third waveguide substrate. After a virtual image with a certain FOV enters the third waveguide substrate, it is diffracted by at least two second coupling gratings and enters the third waveguide substrate for total internal reflection. After reaching the corresponding second coupling grating, the beam with a certain FOV is transmitted to the human eye. At least one first coupling grating and a corresponding number of first coupling gratings have the same transverse period Λx1; at least two second coupling gratings and a corresponding number of second coupling gratings have the same transverse period Λx2.

2. The colorized waveguide display system according to claim 1, characterized in that, The number of first coupling gratings is one, two, or three; the number of second coupling gratings is two or three.

3. The colorized waveguide display system according to claim 2, characterized in that, When there are two first-coupled-in gratings and two second-coupled-in gratings, one first-coupled-in grating and one first-coupled-out grating are responsible for the field of view (FOV) of the first wavelength light, and the other first-coupled-in grating and the other first-coupled-out grating are responsible for the complete field of view (FOV) of the second wavelength light. A second input grating and a second output grating are responsible for the negative field of view (FOV) of diffracting the first wavelength light, while another second input grating and another second output grating are responsible for the complete FOV of diffracting the third wavelength light.

4. The colorized waveguide display system according to claim 1, characterized in that, The coupling grating and the coupling grating are one of the following: surface relief grating, volume holographic grating, or liquid crystal polarizer grating.

5. The colorized waveguide display system according to claim 4, characterized in that, The coupling-in grating and coupling-out grating are either reflective liquid crystal polarizer gratings or transmissive liquid crystal polarizer gratings.

6. The colorized waveguide display system according to claim 1, characterized in that, The difference in display brightness between the first display system and the second display system is less than 20%, and the difference in transmission wavelength between the first display system and the second display system is within 100nm.

7. A smart wearable device, characterized in that, The binocular fusion color waveguide display system includes any one of claims 1-6.

Images