Holographic optical waveguide color display system

Abstract

A holographic optical waveguide color display system. By means of time-division multiplexing combined with the modulation effect of holographic volume gratings on different polarization states, holographic optical waveguide full-color display is realized; and the problems in respect of crosstalk and low diffraction efficiency caused by the response of different gratings to other wavelengths are effectively avoided, and the differences in propagation step lengths caused by different wavelengths responding with different diffraction angles can also be mitigated, thereby further improving the uniformity of color image display in optical waveguides.

Description

Holographic optical waveguide color display system

[0001] Cross-references to related documents

[0002] This application claims priority to the Chinese patent application No. 2024108972522, filed on July 5, 2024, and entitled “Holographic optical waveguide color display system”, the entire content of which is incorporated herein by reference. TECHNICAL FIELD

[0003] Embodiments of the present application belong to the technical field of optical waveguide display, and in particular relate to a holographic optical waveguide color display system. BACKGROUND

[0004] Diffractive optical waveguide display technology is an important development direction in the field of augmented reality (AR), which enables users to see virtual images provided by the device while seeing the real world, i.e., superimposing virtual information in the real world, thereby providing the user with an “enhanced” display effect. At present, most optical waveguide AR display devices on the market are single green display, and there are very few optical waveguide AR products for color display, especially single-layer optical waveguide AR for color display. Due to the dispersion characteristics of the diffraction grating itself, the corresponding diffraction angles of incident light of different wavelengths are different under the same diffraction order, i.e., the angles of transmission of image light of different colors in the waveguide are different, thereby resulting in a smaller field of view angle that can be achieved when a single-layer optical waveguide displays full color. Under the action of the same diffraction grating, there is a large difference in the corresponding diffraction efficiency of different wavelengths, resulting in poor color uniformity of the image. TECHNICAL SOLUTION

[0005] In order to alleviate or solve the above-mentioned technical problems, the present application provides a holographic optical waveguide color display system, which can realize optical waveguide full-color display.

[0006] The present application specifically includes a polarized image light source, a first optical waveguide and a second optical waveguide.

[0007] The polarized image light source output end is provided with a first phase delay device;

[0008] The first optical waveguide and the second optical waveguide are spaced apart by a first grating and a second grating;

[0009] The second optical waveguide is spaced apart by a first polarization state image light processing device and a second polarization state image light processing device on the side away from the first optical waveguide, and the first polarization state image light processing device and the second polarization state image light processing device are respectively arranged in regions corresponding to the positions of the first grating and the second grating;

[0010] The first polarization state image light processing device comprises a second phase delay device, a third grating and a fourth grating;

[0011] The second polarization state image light processing device comprises a third phase delay device, a fifth grating and a sixth grating;

[0012] When the first phase delay device has a phase delay of 0, after the polarization image light source emits first polarization light and second polarization light, the first polarization light or the second polarization light is diffracted in the first grating after passing through the first phase delay device and the first optical waveguide in turn, and continues to be reflected in the first optical waveguide, and finally is output to the human eye to form an image after passing through the second grating and the first optical waveguide in turn;

[0013] When the first phase delay device has a phase delay of Pi, the first polarization light or the second polarization light is diffracted in the first grating after passing through the first phase delay device and the first optical waveguide in turn, the first polarization light or the second polarization light diffracted out of the first grating passes through the second optical waveguide, the second phase delay device, the third grating or the fourth grating, the second phase delay device in turn, continues to be reflected in the second optical waveguide, then passes through the third phase delay device, the fifth grating or the sixth grating, and the third phase delay device in turn, is transmitted to the second grating through the second optical waveguide, and finally is transmitted to the human eye through the first optical waveguide;

[0014] When the polarization image light source emits first polarization light, the first polarization light is diffracted by the third grating in the first polarization state image light processing device and the fifth grating in the second polarization state image light processing device;

[0015] When the polarization image light source emits second polarization light, the first polarization light is diffracted by the fourth grating in the first polarization state image light processing device and the sixth grating in the second polarization state image light processing device.

[0016] As a preferred embodiment of the present application, the first phase delay device is an electrically controlled 1 / 2 wave plate, and the second phase delay device and the third phase delay device are electrically controlled 1 / 4 wave plates.

[0017] As a preferred embodiment of the present application, the first optical waveguide comprises a first optical waveguide unit and a second optical waveguide unit;

[0018] The first optical waveguide unit is arranged on a side surface close to the second optical waveguide, and the second optical waveguide unit is arranged on a side surface of the first optical waveguide unit away from the second optical waveguide;

[0019] The first grating and the second grating are respectively arranged between the first optical waveguide unit and the second optical waveguide unit, and the second phase delay device and the third phase delay device are respectively arranged between the first optical waveguide unit and the second optical waveguide unit; and the second phase delay device and the third phase delay device are respectively arranged in regions corresponding to positions of the first grating and the second grating.

[0020] As a preferred embodiment of the present application, the first polarized light is P light, and the second polarized light is S light.

[0021] The third grating and the fifth grating are left-handed circularly polarized light responsive polarization volume holographic gratings, and the fourth grating and the sixth grating are right-handed circularly polarized light responsive polarization volume holographic gratings.

[0022] As a preferred embodiment of the present application, the first grating and the second grating are both holographic polymer dispersed liquid crystal gratings.

[0023] As a preferred embodiment of the present application, the first grating and the second grating are of a transmission type or a reflection type, and the third grating, the fourth grating, the fifth grating and the sixth grating are all of a reflection type. Advantages

[0024] The present application provides a holographic optical waveguide color display system, which realizes holographic optical waveguide full-color display through time division multiplexing and the modulation of different polarization states by holographic volume gratings, effectively avoids the problems of crosstalk and low diffraction efficiency caused by the response of different gratings to other wavelengths, and also alleviates the transmission step difference caused by different diffraction angles of different wavelength responses, further improves the uniformity of optical waveguide color image display, and has the advantages of small size, thinness, simple preparation, low cost and the like compared with other solutions. BRIEF DESCRIPTION OF DRAWINGS

[0025] The accompanying drawings, which are included to provide a further understanding of the present application and are incorporated in and constitute a part of this application, illustrate certain non-limiting embodiments of the present application and serve to explain the principles of the present application, and do not limit the present application. Some specific embodiments of the present application will be described in detail hereinafter with reference to the accompanying drawings. In the drawings, the same reference numerals indicate the same or similar components or parts, and it should be understood by those skilled in the art that the drawings are not necessarily drawn to scale, and in the drawings:

[0026] FIG. 1 is a light path principle diagram of a holographic optical waveguide color display system according to an embodiment of the present application;

[0027] FIG. 2 is a polarization conversion principle diagram of a first polarization state image light processing device at t2;

[0028] Figure 3 is a schematic diagram of the polarization conversion principle of the second polarization state image light processing device at time t2;

[0029] Figure 4 is a schematic diagram of the polarization conversion principle of the first polarization state image light processing device at time t3;

[0030] Figure 5 is a schematic diagram of the polarization conversion principle of the second polarization state image light processing device at time t3;

[0031] Figure 6 is a schematic diagram of the light path principle of a holographic optical waveguide color display system according to an embodiment of the present application. Best Mode for Carrying Out the Invention

[0032] In order to enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work should fall within the scope of protection of the present application.

[0033] The present application provides a holographic optical waveguide color display system, which mainly comprises a polarized image light source (consisting of a micro display and a collimating lens assembly), a first phase delay device, a first optical waveguide, a second phase delay device, a third phase delay device, a coupling-in grating, and a coupling-out grating. The image light output by the micro display is linearly polarized light, and R, G, and B images are cyclically output at different times. The first phase delay device can adjust the polarization state of the image light entering the first optical waveguide in real time. The second phase delay device and the third phase delay device are synchronized to cooperate with the polarized image light source and the first phase delay device to adjust the polarization state. The coupling-in grating and the coupling-out grating each comprise a first grating, a third grating, a fourth grating, a fifth grating, and a sixth grating. The first grating and the second grating are both holographic polymer dispersed liquid crystal gratings, and the third grating, the fourth grating, the fifth grating, and the sixth grating are all polarization volume holographic gratings. The first grating and the second grating are of a transmission type or a reflection type, and the third grating, the fourth grating, the fifth grating, and the sixth grating are all of a reflection type.

[0034] The technical solutions of the present application will be described in detail below with the first grating, the second grating, the third grating, the fourth grating, the fifth grating, and the sixth grating all being of a reflection type. Embodiment

[0035] As shown in Figures 1, 2, 3, 4, and 5, the present application provides a holographic optical waveguide color display system, which comprises a polarized image light source 1, a first optical waveguide 2, and a second optical waveguide 3.

[0036] The polarization image light source 1 is provided with a first phase delay device 9 at the output end;

[0037] The first optical waveguide 2 and the second optical waveguide 3 are provided with a first grating 4 and a second grating 7 at intervals;

[0038] The second optical waveguide 3 is provided with a first polarization state image light processing device 5 and a second polarization state image light processing device 6 at intervals on the side away from the first optical waveguide 2, and the first polarization state image light processing device 5 and the second polarization state image light processing device 6 are arranged in regions corresponding to the positions of the first grating 4 and the second grating 7 respectively;

[0039] The first polarization state image light processing device 5 comprises a second phase delay device 51, a third grating 52 and a fourth grating 53;

[0040] The second polarization state image light processing device 6 comprises a third phase delay device 61, a fifth grating 62 and a sixth grating 63;

[0041] When the phase delay of the first phase delay device 9 is 0, after the polarization image light source 1 emits first polarized light and second polarized light, the first polarized light or the second polarized light is diffracted in the first grating 4 after passing through the first phase delay device 9 and the first optical waveguide 2 in turn, continues to reflect in the first optical waveguide 2, and is finally output to the human eye 8 for imaging after passing through the second grating 7 and the first optical waveguide 2 in turn;

[0042] When the phase delay of the first phase delay device 9 is Pi, the first polarized light or the second polarized light is diffracted in the first grating 4 after passing through the first phase delay device 9 and the first optical waveguide 2 in turn, the first polarized light or the second polarized light diffracted out of the first grating 4 passes through the second optical waveguide 3, the second phase delay device 51, the third grating 52 or the fourth grating 53, the second phase delay device 51 in turn, continues to reflect in the second optical waveguide 3, then passes through the third phase delay device 61, the fifth grating 62 or the sixth grating 63, and the third phase delay device 61 in turn, is transmitted to the second grating 7 through the second optical waveguide 3, and is finally transmitted to the human eye 8 through the first optical waveguide 2;

[0043] When the polarization image light source 1 emits first polarized light, the first polarized light is diffracted by the third grating 52 in the first polarization state image light processing device 5 and by the fifth grating 62 in the second polarization state image light processing device 6;

[0044] When the polarized image light source 1 emits second polarized light, the first polarized light is diffracted by the fourth grating 53 in the first polarization state image light processing device 5 and the sixth grating 63 in the second polarization state image light processing device 6.

[0045] In the embodiment of the present application, the first phase delay device 9 is an electrically controlled 1 / 2 wave plate, and the second phase delay device 51 and the third phase delay device 61 are electrically controlled 1 / 4 wave plates.

[0046] The polarized image light source 1 (P light is taken as an example, LCD, OLED, LCOS, etc. polarized display light source) in the present application is selected.

[0047] At t1 (the wavelength of the image light source is green light G), the first phase delay device 9 is set to be in a 0 phase modulation state, the P light is propagated in the first optical waveguide 2 in the form of total reflection after the action of the first grating 4, reaches the second grating 7, is diffracted and coupled out of the first optical waveguide 2 into the human eye 8 for imaging;

[0048] At t2 (the wavelength of the image light source is red light R), the first phase delay device 9 is set to be in a pi phase delay (45° angle with the optical axis), so that the P light is converted into S light, directly transmits the first grating 4 in the middle of the first optical waveguide 2, is modulated into left circularly polarized light, is diffracted by the third grating 52 and the second phase delay device 51, is reconverted into S light, is transmitted in the second optical waveguide 3 in the form of total reflection to the third phase delay device 61, is reconverted into left circularly polarized light, and is reconverted into S light under the action of the fifth grating 62 and the third phase delay device 61, and directly transmits the second grating 7 in the first optical waveguide 2 into the human eye 8 for imaging.

[0049] At t3 (the wavelength of the image light source is blue light B), the first phase delay device 9 is set to be in a pi phase delay (45° angle with the optical axis), so that the P light is converted into S light, directly transmits the first grating 4 in the middle of the first optical waveguide 2, is modulated into right circularly polarized light, is diffracted by the fourth grating 53 and the second phase delay device 51, is reconverted into S light, is transmitted in the second optical waveguide 3 in the form of total reflection to the second phase delay device 51, is reconverted into right circularly polarized light, and is reconverted into S light under the action of the sixth grating 63 and the second phase delay device 51, and directly transmits the second grating 7 in the first optical waveguide 2 into the human eye 8 for imaging. Embodiment

[0050] On the basis of the embodiment one, as shown in FIG. 2, FIG. 3, FIG. 4, FIG. 5 and FIG. 6, the first optical waveguide 2 comprises a first optical waveguide unit 21 and a second optical waveguide unit 22;

[0051] The first optical waveguide unit 21 is arranged on the side close to the second optical waveguide 3, and the second optical waveguide unit 22 is arranged on the side away from the second optical waveguide 3 of the first optical waveguide unit 21;

[0052] The first grating 4 and the second grating 7 are respectively arranged between the first optical waveguide unit 21 and the second optical waveguide unit 22, and the second phase delay device 51 and the third phase delay device 61 are respectively arranged between the first optical waveguide unit 21 and the second optical waveguide 3; and the second phase delay device 51 and the third phase delay device 61 are respectively arranged in the regions corresponding to the positions of the first grating 4 and the second grating 7.

[0053] In the embodiment of the present application, the first polarized light is P light, and the second polarized light is S light.

[0054] The third grating 52 and the fifth grating 62 are left-handed circularly polarized light response polarization volume holographic gratings, and the fourth grating 53 and the sixth grating 63 are right-handed circularly polarized light response polarization volume holographic gratings.

[0055] As a preferred embodiment of the present application, the first grating 4 and the second grating 7 are of transmission or reflection type, and the third grating 52, the fourth grating 53, the fifth grating 62 and the sixth grating 63 are all of reflection type.

[0056] The present application selects a polarized image light source 1 (P light is taken as an example, LCD, OLED, LCOS and other polarized display light sources).

[0057] At t1, the first phase delay device 9 is set to 0 phase modulation state, and the P light propagates in the first optical waveguide 2 in the form of total reflection after the action of the first grating 4, and is diffracted and coupled out of the first optical waveguide 2 at the second grating 7 to enter the human eye 8 to form an image;

[0058] At t2, the first phase delay device 9 is set to pi phase delay (45° angle with the optical axis), so that the P light is converted into S light, and directly transmits through the first grating 4 between the first optical waveguide unit 21 and the second optical waveguide unit 22 to the second phase delay device 51, and is modulated into left-handed circularly polarized light into the second optical waveguide 3; then, after the action of the third grating 52, the left-handed circularly polarized light is converted into S light again in the form of total reflection through the second optical waveguide 3 to the fifth grating 62, and is diffracted out of the second optical waveguide 3 again and modulated by the third phase delay device 61, so that the left-handed circularly polarized light is converted into S light again, and directly transmits through the second grating 7 between the first optical waveguide unit 21 and the second optical waveguide unit 22 to the human eye 8 to form an image.

[0059] At t3, the first phase delay device 9 remains unchanged and is set to pi phase delay (45° angle with the optical axis), so that the P light is converted into S light, and directly transmits through the first grating 4 between the first optical waveguide unit 21 and the second optical waveguide unit 22 to the second phase delay device 51, and at this time, the S light is modulated into right-handed circularly polarized light into the second optical waveguide 3; then, after the action of the fourth grating 53, the right-handed circularly polarized light is converted into S light again in the form of total reflection through the second optical waveguide 3 to the sixth grating 63, and is diffracted out of the second optical waveguide 3 again and modulated by the third phase delay device 61, so that the right-handed circularly polarized light is converted into S light again, and directly transmits through the second grating 7 between the first optical waveguide unit 21 and the second optical waveguide unit 22 to the human eye 8 to form an image.

[0060] The present application only needs to control the red, green and blue three-color image source to display images with different polarization states, and ensure that the t1, t2 and t3 time periods are within the human eye visual persistence range, so that the human eye can see a colorful display screen. The present application can solve the problem of uneven color display, has high diffraction efficiency, is light and thin, and is very suitable for wearable near-eye display devices; at the same time, it has higher image resolution (3 times higher) under the same size of display screen, further improving the imaging display effect of the holographic optical waveguide AR display device.

[0061] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, but not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A holographic lightguide color display system, characterized by, The polarization image light source, the first light waveguide and the second light waveguide are included; The first phase delay device is arranged on the output end of the polarization image light source; The first grating and the second grating are arranged between the first light waveguide and the second light waveguide; The first polarization state image light processing device and the second polarization state image light processing device are arranged on the side of the second light waveguide away from the first light waveguide; The first polarization state image light processing device includes the second phase delay device, the third grating and the fourth grating; The second polarization state image light processing device includes the third phase delay device, the fifth grating and the sixth grating; When the phase delay of the first phase delay device is 0, the first polarization light and the second polarization light are emitted by the polarization image light source, then the first polarization light or the second polarization light is diffracted in the first grating after passing through the first phase delay device and the first light waveguide in turn, and is reflected in the first light waveguide, and finally is output to the human eye to form an image after passing through the second grating and the first light waveguide in turn; When the phase delay of the first phase delay device is Pi, the first polarization light or the second polarization light is diffracted in the first grating after passing through the first phase delay device and the first light waveguide in turn, and the first polarization light or the second polarization light diffracted out of the first grating passes through the second light waveguide, the second phase delay device, the third grating or the fourth grating, the second phase delay device, the third phase delay device, the fifth grating or the sixth grating in turn, and then is transmitted to the second grating through the second light waveguide, and finally is transmitted to the human eye through the first light waveguide; When the polarization image light source emits the first polarization light, the first polarization light is diffracted by the third grating in the first polarization state image light processing device and the fifth grating in the second polarization state image light processing device; When the polarization image light source emits the second polarization light, the first polarization light is diffracted by the fourth grating in the first polarization state image light processing device and the sixth grating in the second polarization state image light processing device.

2. A holographic lightguide color display system according to claim 1, wherein, The first phase delay device is an electrically controlled 1 / 2 wave plate, and the second phase delay device and the third phase delay device are electrically controlled 1 / 4 wave plates.

3. A holographic lightguide color display system according to claim 1, wherein, The first light waveguide includes a first light waveguide unit and a second light waveguide unit; The first light waveguide unit is arranged on the side close to the second light waveguide, and the second light waveguide unit is arranged on the side of the first light waveguide unit away from the second light waveguide. The first grating and the second grating are respectively arranged between the first optical waveguide unit and the second optical waveguide unit, and the second phase delay device and the third phase delay device are respectively arranged between the first optical waveguide unit and the second optical waveguide unit; and the second phase delay device and the third phase delay device are respectively arranged in regions corresponding to positions of the first grating and the second grating.

4. A holographic lightguide color display system according to claim 1, wherein, The first polarized light is P light, and the second polarized light is S light. The third grating and the fifth grating are left-handed circularly polarized light responsive polarization volume holographic gratings, and the fourth grating and the sixth grating are right-handed circularly polarized light responsive polarization volume holographic gratings.

5. A holographic lightguide color display system according to claim 1, wherein, The first grating and the second grating are both holographic polymer dispersed liquid crystal volume gratings.

6. A holographic lightguide color display system according to claim 1, wherein, The first grating and the second grating are of a transmission type or a reflection type, and the third grating, the fourth grating, the fifth grating and the sixth grating are all of a reflection type.

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