Light guide display system and display method thereof

Abstract

The present application discloses a light guide display system and a display method thereof. The light guide display system includes: a light guide member, the light guide member including an incoupling region and an outcoupling region; a liquid crystal polarization grating, the liquid crystal polarization grating disposed on one side of the outcoupling region; a phase retarder, the phase retarder disposed between the outcoupling region and the liquid crystal polarization grating; and a polarizer, the polarizer disposed between the outcoupling region and the phase retarder. The light guide display system of the present application, by disposing a liquid crystal polarization grating in the outcoupling region of the light guide member, modulates the outcoupling light of the light guide member, thereby greatly expanding the field of view of the light guide member.

Description

Technical Field

[0001] The present application relates to the field of light guide display technology, and more specifically, to a light guide display system and a display method of the light guide display system. Background Art

[0002] In existing technologies, increasing the waveguide's field of view (FOV) is typically achieved by increasing the refractive index of the waveguide material. However, due to limitations in the waveguide's inherent material, further increasing the refractive index is difficult. Consequently, further increasing the waveguide's theoretical FOV is also difficult. Summary of the Invention

[0003] One purpose of the present application is to provide a new technical solution for a light guide display system, which can at least solve the problem of limited expansion of the field of view angle of the light waveguide in the prior art.

[0004] According to a first aspect of the present application, a light guide display system is provided, comprising: a light guide member, the light guide member comprising an incoupling region and an outcoupling region; a liquid crystal polarization grating, the liquid crystal polarization grating being arranged on one side of the outcoupling region; a phase retarder, the phase retarder being arranged between the outcoupling region and the liquid crystal polarization grating; and a polarizer, the polarizer being arranged between the outcoupling region and the phase retarder.

[0005] Optionally, the light guide display system further includes a display, the display being configured to emit light, and the display being disposed on one side of the coupling-in area.

[0006] Optionally, the refresh frequency of the display matches the modulation frequency of the liquid crystal polarization grating.

[0007] Optionally, the liquid crystal polarization grating includes a first transparent substrate, a first conductive film, a liquid crystal layer, a second conductive film and a second transparent substrate arranged in sequence. When no driving voltage is applied to the liquid crystal polarization grating, the liquid crystal polarization grating is in a first state; when a driving voltage is applied to the liquid crystal polarization grating, the liquid crystal polarization grating is in a second state.

[0008] Optionally, when no driving voltage is applied to the liquid crystal polarization grating, the transmission direction of the light does not change; when a driving voltage is applied to the liquid crystal polarization grating, the transmission direction of the light is deflected.

[0009] Optionally, the phase retarder is a quarter-wave plate.

[0010] Optionally, the coupling-in region and the coupling-out region are arranged on the same side or on different sides of the light guide.

[0011] Optionally, the coupling-in region is provided with a coupling-in grating, the coupling-out region is provided with a coupling-out grating, and the coupling-out grating, the polarizer, the phase retarder and the liquid crystal polarization grating are sequentially attached or spaced apart.

[0012] Optionally, when the liquid crystal polarization grating is in the first state, a first sub-field of view is formed; when the liquid crystal polarization grating is in the second state, a second sub-field of view is formed; the first sub-field of view and the second sub-field of view are combined to form a total field of view.

[0013] According to a second aspect of the present application, a display method of a light guide display system is provided, which is applied to the light guide display system described in the above embodiment, and the display method comprises the following steps:

[0014] coupling light into the coupling-in region of the light guide and coupling light out from the coupling-out region of the light guide;

[0015] The light coupled out of the light guide passes through a polarizer, a phase retarder and a liquid crystal polarization grating in sequence;

[0016] The liquid crystal polarization grating is controlled to switch between a first state and a second state; wherein, when the liquid crystal polarization grating is in the first state, the light transmission direction remains unchanged and a first sub-field of view is formed; and when the liquid crystal polarization grating is in the second state, the light transmission direction is deflected and a second sub-field of view is formed, and the first sub-field of view and the second sub-field of view are combined to form a total field of view.

[0017] According to the light guide display system of the embodiment of the present invention, a liquid crystal polarization grating is provided in the outcoupling region of the light guide to modulate the outcoupling light of the light guide, thereby greatly expanding the field of view of the light guide.

[0018] Other features and advantages of the present application will become apparent from the following detailed description of exemplary embodiments of the present application with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the application and, together with the description, serve to explain the principles of the application.

[0020] Figure 1 is a display schematic diagram of the light guide display system of the present invention in a first state;

[0021] Figure 2 is a display schematic diagram of the light guide display system of the present invention in the second state;

[0022] Figure 3 is a schematic structural diagram of the liquid crystal polarization grating of the present invention in the first state;

[0023] Figure 4 It is a schematic structural diagram of the liquid crystal polarization grating of the present invention in the second state.

[0024] Reference numerals:

[0025] Light guide 10;

[0026] Liquid crystal polarization grating 20; first transparent substrate 21; first conductive film 22; liquid crystal layer 23; second conductive film 24; second transparent substrate 25;

[0027] Phase retarder 30;

[0028] Polarizer 40;

[0029] Display 50;

[0030] Incoupling grating 61; outcoupling grating 62. DETAILED DESCRIPTION

[0031] Various exemplary embodiments of the present application will now be described in detail with reference to the accompanying drawings. It should be noted that unless otherwise specifically stated, the relative arrangements of components and steps, numerical expressions and numerical values ​​set forth in these embodiments do not limit the scope of the present application.

[0032] The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the present disclosure, its application, or uses.

[0033] Technologies, methods, and equipment known to ordinary technicians in the relevant art may not be discussed in detail, but where appropriate, the technologies, methods, and equipment should be considered part of the specification.

[0034] In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not limiting. Therefore, other examples of the exemplary embodiments may have different values.

[0035] It should be noted that like reference numerals and letters refer to like items in the following figures, and therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0036] The light guide display system according to an embodiment of the present invention will be described in detail below with reference to the accompanying drawings.

[0037] like Figures 1 to 4 As shown, the light guide display system according to an embodiment of the present invention includes a light guide member 10 , a liquid crystal polarization grating 20 , a phase retarder 30 and a polarizer 40 .

[0038] Specifically, the light guide 10 includes an incoupling region and an outcoupling region, and is thus an optical waveguide. A liquid crystal polarization grating 20 is disposed on one side of the outcoupling region. A phase retarder 30 is disposed between the outcoupling region and the liquid crystal polarization grating 20. A polarizer 40 is disposed between the outcoupling region and the phase retarder 30.

[0039] In other words, see Figure 1 and Figure 2 According to an embodiment of the present invention, the light guide display system mainly comprises a light guide 10, a liquid crystal polarization grating 20, a phase retarder 30 and a polarizer 40. The light guide 10 has an incoupling region and an outcoupling region. The light guide 10 can be an optical element that can be used for light guiding, such as a waveguide, an optical waveguide or a waveguide plate. In the following embodiments of the present application, the light guide 10 can be specifically described as an optical waveguide. The incoupling region of the light guide 10 can couple the imaging light beam into the light guide 10. The outcoupling region can couple the imaging light beam in the light guide 10 out of the light guide 10. The liquid crystal polarization grating 20 is arranged on one side of the outcoupling region. The phase retarder 30 is arranged between the outcoupling region and the liquid crystal polarization grating 20. The polarizer 40 is arranged between the outcoupling region and the phase retarder 30. The light coupled out through the outcoupling region passes through the polarizer 40, the phase retarder 30 and the liquid crystal polarization grating 20 in sequence. After passing through the polarizer 40, the light forms linearly polarized light. After passing through the phase retarder 30, the linearly polarized light is converted into first circularly polarized light having a first circular polarization state. The liquid crystal polarization grating 20 can adjust the first circularly polarized light, so that the light emitted after passing through the liquid crystal polarization grating 20 can switch between the first circularly polarized light and the second circularly polarized light, thereby expanding the field of view of the light guide 10.

[0040] In the present application, the first circularly polarized light may be right-handed circularly polarized light having a right circular polarization state (RCP: Right circular polarization), and the first circularly polarized light may also be left-handed circularly polarized light having a left-handed circular polarization state (LCP: Left circular polarization). Taking the right-handed circularly polarized light having a right circular polarization state as an example, see Figure 3 and Figure 4 After passing through the liquid crystal polarization grating 20, the emitted light can switch between right-handed circularly polarized light and left-handed circularly polarized light, presenting two different viewing positions, and can double the viewing angle of the light guide 10. This application achieves an increase in viewing angle without changing the refractive index of the material of the light guide 10 (e.g., the optical waveguide), effectively solving the problem in the prior art of limited viewing angle expansion of the optical waveguide due to the refractive index limit of the optical waveguide material.

[0041] Therefore, the light guide display system according to the embodiment of the present invention provides a liquid crystal polarization grating 20 in the outcoupling region of the light guide 10 to modulate the outcoupling light of the light guide 10 , thereby greatly expanding the field of view of the light guide 10 .

[0042] According to an embodiment of the present invention, the light guide display system further includes a display 50, which is configured to emit light and is disposed on one side of the coupling region.

[0043] That is to say, if Figure 1 and Figure 2 As shown, the light guide display system further includes a display 50, which can be used to emit an imaging light beam. The display 50 can be disposed on one side of the coupling-in region of the light guide 10. The display 50 can be spaced apart and arranged opposite to the coupling-in region of the light guide 10. The imaging light beam generated by the display 50 is coupled into the light guide 10 through the coupling-in region. The light within the light guide 10 is then coupled out to the polarizer 40 through the outcoupling region after undergoing total internal reflection. Finally, it is emitted after passing through the phase retarder 30 and the liquid crystal polarization grating 20. The liquid crystal polarization grating 20 modulates the outcoupled light from the light guide 10, greatly expanding the field of view of the light guide 10.

[0044] In some embodiments of the present invention, the refresh rate of the display 50 matches the modulation frequency of the liquid crystal polarization grating 20 .

[0045] In other words, the outcoupled light can present two circularly polarized lights with different polarization states after being modulated by the liquid crystal polarization grating 20, thereby presenting two fields of view at different positions ( Figure 1 Showing the right half of the flower, Figure 2 At the same time, when the refresh rate of the display 50 and the modulation frequency of the liquid crystal polarization grating 20 match each other, the effect of expanding the field of view of the light waveguide is achieved.

[0046] According to one embodiment of the present invention, a liquid crystal polarization grating 20 includes a first transparent substrate 21, a first conductive film 22, a liquid crystal layer 23, a second conductive film 24, and a second transparent substrate 25, which are arranged in sequence. When no driving voltage is applied to the liquid crystal polarization grating 20, the liquid crystal polarization grating 20 is in a first state. When a driving voltage is applied to the liquid crystal polarization grating 20, the liquid crystal polarization grating 20 is in a second state.

[0047] That is, see Figure 3 and Figure 4The liquid crystal polarization grating 20 is mainly composed of a first transparent substrate 21, a first conductive film 22, a liquid crystal layer 23, a second conductive film 24 and a second transparent substrate 25, wherein the first conductive film 22 and the second conductive film 24 can be made of ITO (Indium Tin Oxide) films respectively. The liquid crystal molecules in the liquid crystal layer 23 can be controlled by an electric field. The first conductive film 22 and the second conductive film 24 are switched between different states of the liquid crystal polarization grating 20 by applying an external voltage. When no external driving voltage is applied to the liquid crystal polarization grating 20, such as Figure 3 As shown in FIG. 1 , the liquid crystal polarization grating 20 is in the first state. When a driving voltage is applied to the liquid crystal polarization grating 20, as shown in FIG. Figure 4 As shown, the liquid crystal polarization grating 20 is in the second state. By applying an external driving voltage to modulate the switching of the liquid crystal polarization grating 20 between the first state and the second state, the outcoupled light of the light guide 10 is modulated, which greatly expands the field of view of the light guide 10.

[0048] According to an embodiment of the present invention, when no driving voltage is applied to the liquid crystal polarization grating 20 , the transmission direction of the light does not change. When a driving voltage is applied to the liquid crystal polarization grating 20 , the transmission direction of the light deflects.

[0049] In other words, see Figure 1 and Figure 3 When no driving voltage is applied to the liquid crystal polarization grating 20, the light coupled out of the outcoupling region of the light guide 10 passes through the polarizer 40 and the phase retarder 30 and then enters the liquid crystal polarization grating 20. At this time, the light maintains the first circular polarization state, the transmission direction of the light does not change, and the light can directly exit the liquid crystal polarization grating 20. When a driving voltage is applied to the liquid crystal polarization grating 20, as shown in FIG. Figure 2 and Figure 4 As shown, the light coupled out of the outcoupling region of the light guide 10 passes through the polarizer 40 and the phase retarder 30 and then enters the liquid crystal polarization grating 20. At this point, the first source polarized light having a first circular polarization state is converted into the second circular polarization light having a second circular polarization state, and the propagation direction of the light is deflected. By controlling the switching of the liquid crystal polarization grating 20 between the pressurized state and the unpressurized state, the liquid crystal polarization grating 20 switches between the first state and the second state, ensuring that after modulation by the liquid crystal polarization grating 20, circularly polarized light with two different polarization states can be presented, thereby presenting two different fields of view. At the same time, when the refresh rate of the display 50 and the modulation frequency of the liquid crystal polarization grating 20 match each other, the field of view of the optical waveguide can be doubled.

[0050] Taking the light after passing through the phase retarder 30 as right-handed circularly polarized light as an example, when no external driving voltage is applied to the liquid crystal polarization grating 20, as shown in FIG. Figure 3As shown in FIG, after the right-handed circularly polarized light (RCP) passes through the liquid crystal polarization grating 20, the polarization state remains unchanged, the transmission direction of the right-handed circularly polarized light does not change, and the light directly exits the liquid crystal polarization grating 20 along the original transmission direction. When a driving voltage is applied to the liquid crystal polarization grating 20, as shown in FIG. Figure 4 As shown, after right-handed circularly polarized light (RCP) passes through the liquid crystal polarization grating 20, its polarization state changes to left-handed circularly polarized light (LCP). The propagation direction of the light does not change, but the light is deflected after passing through the liquid crystal polarization grating 20. By switching the liquid crystal polarization grating 20 between the first and second states, two different viewing positions can be presented, greatly improving the viewing field of the optical waveguide.

[0051] In some specific embodiments of the present invention, the phase retarder 30 may be a quarter wave plate, which can convert linearly polarized light after passing through the polarizer 40 into circularly polarized light, thus meeting the application requirements of the light guide display system.

[0052] According to one embodiment of the present invention, the coupling-in region and the coupling-out region are arranged on the same side or on different sides of the light guide 10 .

[0053] That is, see Figure 1 The light guide 10 may have an incoupling region and an outcoupling region on the same side. Incoupling regions and outcoupling regions may also be provided on opposite sides of the light guide 10. Any design that can ensure that light coupled in through the incoupling region can be coupled out through the outcoupling region is within the scope of protection of this application and will not be described in detail in this application.

[0054] According to one embodiment of the present invention, a coupling-in grating 61 is provided in the coupling-in region, and a coupling-out grating 62 is provided in the coupling-out region. The coupling-out grating 62, the polarizer 40, the phase retarder 30 and the liquid crystal polarization grating 20 are sequentially attached or spaced apart.

[0055] In other words, if Figure 1 and Figure 2 As shown, the coupling-in region of the light guide 10 is provided with a coupling-in grating 61, which can couple the light generated by the display 50 into the light guide 10. The coupling-out region of the light guide 10 is provided with a coupling-out grating 62, which can couple the light that has undergone total reflection in the light guide 10 out of the light guide 10. The coupling-out grating 62, the polarizer 40, the phase retarder 30 and the liquid crystal polarization grating 20 can be arranged in sequence to shorten the transmission path of the light and reduce the overall space occupied by the light guide display system. Of course, the coupling-out grating 62, the polarizer 40, the phase retarder 30 and the liquid crystal polarization grating 20 can also be arranged in sequence and spaced apart, which will not be described in detail in this application.

[0056] According to one embodiment of the present invention, when the liquid crystal polarization grating 20 is in the first state, a first sub-field of view is formed. When the liquid crystal polarization grating 20 is in the second state, a second sub-field of view is formed. The first sub-field of view and the second sub-field of view are combined to form the total field of view.

[0057] That is, when no external driving voltage is applied to the liquid crystal polarization grating 20, Figure 1 and Figure 3 The light coupled out of the outcoupling region of the light guide 10 passes through the polarizer 40 and the phase retarder 30 and then enters the liquid crystal polarization grating 20. The liquid crystal polarization grating 20 is in the first state. At this time, the light maintains the first circular polarization state, and the transmission direction of the light does not change. The light can directly exit the liquid crystal polarization grating 20 to form a first sub-field of view (display Figure 1 When a driving voltage is applied to the liquid crystal polarization grating 20, see Figure 2 and Figure 4 , the liquid crystal polarization grating 20 is in the second state, and the light coupled out of the coupling region of the light guide 10 passes through the polarizer 40 and the phase retarder 30 and then enters the liquid crystal polarization grating 20. At this time, the first source polarized light with the first circular polarization state is converted into the second circular polarization light with the second circular polarization state, and the transmission direction of the light is deflected, forming a second sub-field of view (display Figure 2 The first and second sub-fields of view combine to form the total field of view, doubling the field of view of the optical waveguide.

[0058] In summary, according to the light guide display system of an embodiment of the present invention, by setting a liquid crystal polarization grating 20 in the outcoupling area of ​​the light guide 10 and controlling the switching of different states of the liquid crystal polarization grating 20, the outcoupling light of the light guide 10 is modulated, thereby greatly expanding the field of view of the light guide 10.

[0059] According to a second aspect of the present application, a display method of a light guide display system is provided, which is applied to the light guide display system in the above embodiment. The display method includes the following steps:

[0060] Couple light into the coupling-in region of the light guide 10 and couple light out from the coupling-out region of the light guide 10;

[0061] The light out of the light guide 10 passes through the polarizer 40, the phase retarder 30 and the liquid crystal polarization grating 20 in sequence;

[0062] The liquid crystal polarization grating 20 is controlled to switch between a first state and a second state; wherein, when the liquid crystal polarization grating 20 is in the first state, the light transmission direction remains unchanged and a first sub-field of view is formed; when the liquid crystal polarization grating 20 is in the second state, the light transmission direction is deflected and a second sub-field of view is formed. The first sub-field of view and the second sub-field of view are combined to form a total field of view.

[0063] That is, see Figures 1 to 4 In the display method of the light guide display system according to the embodiment of the present invention, first, Figure 1 and Figure 2 As shown, light can be coupled into the coupling-in region of the light guide 10, and the light is coupled out from the coupling-out region of the light guide 10 after being totally reflected by the light guide 10. The light can be an imaging light beam generated by the display 50. Then, the light coupled out of the light guide 10 can pass through the polarizer 40, the phase retarder 30, and the liquid crystal polarization grating 20 in sequence. The light coupled out through the coupling-out region passes through the polarizer 40, the phase retarder 30, and the liquid crystal polarization grating 20 in sequence. After passing through the polarizer 40, the light forms linearly polarized light, and after passing through the phase retarder 30, the linearly polarized light is converted into first circularly polarized light having a first circular polarization state.

[0064] Finally, the liquid crystal polarization grating 20 is controlled to switch between the first state and the second state. Figure 1 and Figure 3 , no external driving voltage is applied to the liquid crystal polarization grating 20. Light coupled out of the outcoupling region of the light guide 10 passes through the polarizer 40 and the phase retarder 30 before entering the liquid crystal polarization grating 20. At this point, the light maintains the first circular polarization state, and the propagation direction of the light remains unchanged, allowing the light to directly exit the liquid crystal polarization grating 20. The light propagation direction remains unchanged, forming a first sub-field of view.

[0065] When the liquid crystal polarization grating 20 is in the second state, see Figure 2 and Figure 4 , a driving voltage is applied to the liquid crystal polarization grating 20, and the light coupled out of the outcoupling region of the light guide 10 passes through the polarizer 40 and the phase retarder 30 and then enters the liquid crystal polarization grating 20. At this time, the first source polarized light with a first circular polarization state is converted into the second circular plate polarized light with a second circular polarization state, and the propagation direction of the light is deflected. The propagation direction of the light is deflected, and a second sub-field of view is formed. The first sub-field of view and the second sub-field of view are combined to form the total field of view. By controlling the switching of the liquid crystal polarization grating 20 between the first state and the second state, it is ensured that after being modulated by the liquid crystal polarization grating 20, two circularly polarized lights with two different polarization states can be presented, thereby presenting two fields of view at different positions, thereby expanding the field of view of the optical waveguide.

[0066] Of course, for those skilled in the art, other structures and working principles of the light guide display system are understandable and achievable, and will not be described in detail in this application.

[0067] Although some specific embodiments of the present application have been described in detail by way of examples, it should be understood by those skilled in the art that the above examples are for illustration only and are not intended to limit the scope of the present application. It should be understood by those skilled in the art that the above embodiments may be modified without departing from the scope and spirit of the present application. The scope of the present application is defined by the appended claims.

Claims

1. A light guide display system, characterized in that: include: a light guide, the light guide comprising an incoupling region and an outcoupling region; a liquid crystal polarization grating, the liquid crystal polarization grating being arranged on one side of the outcoupling region; a phase retarder, the phase retarder being arranged between the outcoupling region and the liquid crystal polarization grating; a polarizer, the polarizer being arranged between the outcoupling region and the phase retarder; When no driving voltage is applied to the liquid crystal polarization grating, the liquid crystal polarization grating is in a first state, and the transmission direction of the light does not change; when a driving voltage is applied to the liquid crystal polarization grating, the liquid crystal polarization grating is in a second state, and the transmission direction of the light is deflected; When the liquid crystal polarization grating is in the first state, a first sub-field of view is formed. When the liquid crystal polarization grating is in the second state, a second sub-field of view is formed. The first sub-field of view and the second sub-field of view are combined to form a total field of view.

2. The light guide display system according to claim 1, wherein: Also includes: A display is used to emit light and is arranged on one side of the coupling region.

3. The light guide display system according to claim 2, wherein: The refresh rate of the display matches the modulation frequency of the liquid crystal polarization grating.

4. The light guide display system according to claim 1, wherein: The liquid crystal polarization grating includes a first transparent substrate, a first conductive film, a liquid crystal layer, a second conductive film and a second transparent substrate which are arranged in sequence.

5. The light guide display system according to claim 1, wherein: The phase retarder is a quarter wave plate.

6. The light guide display system according to claim 1, wherein: The coupling-in region and the coupling-out region are arranged on the same side or on different sides of the light guide member.

7. The light guide display system according to claim 6, wherein: The coupling-in region is provided with a coupling-in grating, the coupling-out region is provided with a coupling-out grating, and the coupling-out grating, the polarizer, the phase retarder and the liquid crystal polarization grating are sequentially attached or spaced apart.

8. A display method of a light guide display system, applied to the light guide display system according to any one of claims 1 to 7, characterized in that: The following steps are involved: coupling light into the coupling-in region of the light guide and coupling light out from the coupling-out region of the light guide; The light coupled out of the light guide passes through a polarizer, a phase retarder and a liquid crystal polarization grating in sequence; The liquid crystal polarization grating is controlled to switch between a first state and a second state; wherein, when the liquid crystal polarization grating is in the first state, the light transmission direction remains unchanged and a first sub-field of view is formed; and when the liquid crystal polarization grating is in the second state, the light transmission direction is deflected and a second sub-field of view is formed, and the first sub-field of view and the second sub-field of view are combined to form a total field of view.

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