Liquid crystal optical waveguide coupling input device and augmented reality display device
By using a double-layer structure of polarizing plate and liquid crystal grating in the liquid crystal waveguide coupling input device, the polarization state of the light beam is changed, solving the problem of coupled light beam caused by the rotation direction conversion of the light beam, and realizing the application of large-area liquid crystal waveguide coupling input device.
Patent Information
- Application Number
- CN202423197748.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-24
- Publication Date
- 2025-10-31
- Estimated Expiration
- 2034-12-24
AI Technical Summary
Existing liquid crystal coupled input devices, when in use, cause the beam to be coupled out after the beam rotation is reversed, which limits the device area and prevents large-area application.
The liquid crystal waveguide coupling input device with a dual-layer structure changes the polarization state of the light beam by combining a polarizing plate and a liquid crystal grating, so that the polarization state of the light beam is the same each time it enters the liquid crystal grating, thus avoiding the coupling out of the light beam and realizing large-area coupling input.
This invention achieves a sufficiently large area for the light beam coupling input in the liquid crystal waveguide, meeting the requirements for large-area coupling input, with a simple structure and low processing cost.
Smart Images
Figure CN223501271U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of augmented reality display technology, and in particular to a liquid crystal waveguide coupled input device and an augmented reality display apparatus. Background Technology
[0002] Polymer liquid crystal gratings are commonly used liquid crystal coupled input devices. By introducing a longitudinal period, they enable the device to have good diffraction efficiency and have the advantage of being thin and light, which can effectively reduce the size and weight of the entire optical system when used as a diffractive optical element. At the same time, they have polarization selectivity, which only works on the original polarized light in one direction and has no effect on the circularly polarized light in the other direction, thus allowing real-world objects to enter the human eye with high transmittance.
[0003] However, in existing liquid crystal coupled-in-the-loop (LCD) devices, assuming the light beam emitted from the phase source is left-handed circularly polarized, it will be converted to right-handed circular polarization after being deflected by the liquid crystal grating. This right-handed circularly polarized light, after total internal reflection at the glass-air interface, will couple out as left-handed circularly polarized light if it re-enters the liquid crystal grating. This characteristic limits the area of the LCD device. Figure 1 and Figure 2 As shown, Figure 1 This shows the optical path diagram when the area of the liquid crystal coupled input device is small. Figure 2 The diagram shows the optical path when the area of the liquid crystal coupling input device is large. It can be seen that once the area of the liquid crystal coupling input device is too large, it will couple out after entering the liquid crystal grating for the second time, which will affect its performance and will also prevent the area of the phase source from being large. Utility Model Content
[0004] In order to overcome the shortcomings of the prior art, the purpose of this utility model is to provide a liquid crystal waveguide coupled input device and an augmented reality display device, which has the advantage of realizing large-area liquid crystal grating coupled input.
[0005] The objective of this utility model is achieved through the following technical solution:
[0006] According to a first aspect of the present disclosure, a liquid crystal waveguide coupled input device is provided, comprising:
[0007] A polarizing plate is used to attach to the waveguide substrate to change the polarization state of a light beam.
[0008] A liquid crystal grating supported on the polarizing waveplate is used to reflect the light beam back to the polarizing waveplate and change the polarization state of the light beam;
[0009] After the light beam is emitted from the phase source, it passes through the waveguide substrate and enters the polarizing plate with an initial polarization state. It then enters the liquid crystal grating and is reflected back to the polarizing plate by the liquid crystal grating, where its polarization state changes once. After being reflected again by the waveguide substrate, it enters the polarizing plate again, causing a second polarization state change. This ensures that the polarization state of the light beam when it enters the liquid crystal grating is the same as its initial state, until it finally leaves the liquid crystal waveguide coupling input device and continues to propagate along the waveguide substrate.
[0010] To achieve the above technical solution, a dual-layer coupling input device is used. After the light beam is emitted from the phase source, it passes through the polarization waveplate and enters the liquid crystal grating in either a left-handed or right-handed circularly polarized state. The liquid crystal grating reflects the light beam and changes its polarization state. The light beam re-enters the polarization waveplate and is reflected by the waveguide substrate layer, passing through the polarization waveplate again and entering the liquid crystal grating. At this time, the polarization state of the light beam entering the liquid crystal grating changes back to the initial state, thus preventing coupling out when entering the liquid crystal grating. The light beam can be reflected again by the liquid crystal grating and enter the waveguide substrate layer for transmission until it finally detaches from the liquid crystal waveguide coupling input device and continues to propagate in the waveguide substrate layer. It can be seen that the state of the light beam is the same each time it enters the polarization waveplate. Therefore, the area of the liquid crystal waveguide coupling input device can be set large enough to meet the requirements of large-area coupling input.
[0011] In some exemplary embodiments, after the light beam passes through the polarizing plate and is reflected back to the liquid crystal grating by the waveguide substrate, it can be converted from left-handed circularly polarized light to right-handed circularly polarized light, or from right-handed circularly polarized light to left-handed circularly polarized light.
[0012] In some exemplary embodiments, the liquid crystal grating is capable of converting right-handed circularly polarized light into left-handed circularly polarized light, or converting left-handed circularly polarized light into right-handed circularly polarized light, and the conversion direction of the liquid crystal grating is opposite to that of the polarizing waveplate.
[0013] According to a second aspect of the present disclosure, an augmented reality display device is provided, comprising:
[0014] A waveguide substrate layer is used to propagate the light beam generated by the phase source;
[0015] As described in the first aspect, the liquid crystal waveguide coupled input device is disposed on a first side of the waveguide substrate layer;
[0016] A coupling output device is disposed on the second side of the waveguide substrate layer and is used to couple and output a light beam.
[0017] After being emitted from the phase source, the light beam passes through the waveguide substrate and enters the liquid crystal waveguide coupling input device for coupling input processing. It then propagates from the waveguide substrate to the coupling output device, and after being coupled output by the coupling output device, it is transmitted to the human eye.
[0018] In some exemplary embodiments, the waveguide substrate is a car windshield or an AR glasses lens.
[0019] In some exemplary embodiments, the reflection angle of the light beam as it propagates in the waveguide substrate is greater than the total reflection angle to achieve full transmission in the waveguide substrate.
[0020] In summary, compared with the prior art, this utility model has the following beneficial effects:
[0021] This utility model provides a liquid crystal waveguide coupled input device and an augmented reality display device. The liquid crystal waveguide coupled input device includes: a polarizing waveplate for attaching to a waveguide substrate to change the polarization state of a light beam; and a liquid crystal grating supported on the polarizing waveplate for reflecting the light beam back to the polarizing waveplate and changing the polarization state of the light beam. After the light beam is emitted from the phase source, it passes through the waveguide substrate and enters the polarizing waveplate with an initial polarization state. It is then reflected back to the polarizing waveplate by the liquid crystal grating and undergoes a first polarization state change. After being reflected again by the waveguide substrate, it re-enters the polarizing waveplate to undergo a second polarization state change, so that the polarization state of the light beam when entering the liquid crystal grating is the same as the initial state, until it finally leaves the liquid crystal waveguide coupled input device and continues to propagate along the waveguide substrate. By setting a dual-layer coupling input device, the light beam emitted from the phase source passes through the polarizing waveplate and enters the liquid crystal grating in either left-handed or right-handed circularly polarized state. The liquid crystal grating reflects the light beam and changes its polarization state. After the light beam re-enters the polarizing waveplate, it is reflected by the waveguide substrate and re-enters the liquid crystal grating. At this time, the polarization state of the light beam entering the liquid crystal grating changes back to the initial state, thus preventing coupling out when entering the liquid crystal grating. The light beam can be reflected again by the liquid crystal grating and enter the waveguide substrate for transmission until it finally detaches from the liquid crystal waveguide coupling input device and continues to propagate in the waveguide substrate. It can be seen that the state of the light beam is the same each time it enters the polarizing waveplate. Therefore, the area of the liquid crystal waveguide coupling input device can be set large enough to meet the requirements of large-area coupling input. Attached Figure Description
[0022] Figure 1 This is an optical path diagram in the background art when the area of the liquid crystal coupled input device is small.
[0023] Figure 2 This is the optical path diagram in the background art when the area of the liquid crystal coupled input device is large.
[0024] Figure 3 This is a schematic diagram of the structure of the liquid crystal waveguide coupled input device in the embodiment of this utility model.
[0025] Figure 4 This is a schematic diagram of the augmented reality display device in an embodiment of the present invention.
[0026] The numbers and letters in the diagram represent the names of the corresponding components:
[0027] 100 Waveguide substrate; 200 Coupled input device; 201 Polarizing waveplate; 202 Liquid crystal grating; 300 Phase source; 400 Coupled output device. Detailed Implementation
[0028] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.
[0029] like Figure 3 As shown, a first aspect of this utility model provides a liquid crystal waveguide coupling input device 200, comprising: a polarizing waveplate 201 for bonding with a waveguide substrate 100 to change the polarization state of a light beam; and a liquid crystal grating 202 supported on the polarizing waveplate 201 for reflecting the light beam back to the polarizing waveplate 201 and changing the polarization state of the light beam. The light beam, emitted from a phase source 300, passes through the waveguide substrate 100 and enters the polarizing waveplate 201 with an initial polarization state. It then enters the liquid crystal grating 202, is reflected back to the polarizing waveplate 201 by the liquid crystal grating 202, undergoes a first polarization state change, and is reflected again by the waveguide substrate 100 to re-enter the polarizing waveplate 201, causing a second polarization state change. This ensures that the polarization state of the light beam entering the liquid crystal grating 202 is the same as the initial state, until it finally detaches from the liquid crystal waveguide coupling input device 200 and continues to propagate along the waveguide substrate 100.
[0030] Among them, the polarizing waveplate 201 needs to be able to completely change the polarization state of the light beam. Specifically, after the light beam passes through the polarizing waveplate 201 and is reflected back to the liquid crystal grating 202 by the waveguide substrate 100, it can be converted from left-hand circularly polarized light to right-hand circularly polarized light, or from right-hand circularly polarized light to left-hand circularly polarized light. The liquid crystal grating 202 can convert right-hand circularly polarized light to left-hand circularly polarized light, or convert left-hand circularly polarized light to right-hand circularly polarized light. Moreover, the conversion direction of the liquid crystal grating 202 is opposite to that of the polarizing waveplate 201. The selection of the polarizing waveplate 201 and the liquid crystal grating 202 can be specifically determined according to the characteristics of the phase source 300. The polarizing waveplate 201 and the liquid crystal grating 202, and the polarizing waveplate 201 and the waveguide substrate 100 can be fixed by photoresist.
[0031] like Figure 3 As shown, when the light beam emitted by the phase source 300 passes through the waveguide substrate 100 and the polarizing plate 201 and enters the liquid crystal grating 202 from point A as left-handed circularly polarized light, the liquid crystal grating 202 deflects and reflects the light beam, converting it into right-handed circularly polarized light. This right-handed circularly polarized light is reflected again from point B into the polarizing plate 201, and after being reflected again by the polarizing plate 201 and the waveguide substrate 100, it is converted into left-handed circularly polarized light. It then enters the liquid crystal grating 202 again from point C, and is deflected and reflected again by the liquid crystal grating 202, converting it into right-handed circularly polarized light. It is then reflected again from point D into the polarizing plate 201. This process is repeated until the light beam is removed from the liquid crystal waveguide coupling input device 200 and continues to propagate in the waveguide substrate 100.
[0032] Conversely, when the light beam emitted from the phase source 300 passes through the waveguide substrate 100 and the polarizing plate 201 and enters the liquid crystal grating 202 at point A as right-handed circularly polarized light, the liquid crystal grating 202 deflects and reflects the light beam, converting it into left-handed circularly polarized light. This left-handed circularly polarized light is reflected again from point B into the polarizing plate 201, and after being reflected again by the polarizing plate 201 and the waveguide substrate 100, it is converted into right-handed circularly polarized light. It then enters the liquid crystal grating 202 again from point C, where the liquid crystal grating 202 deflects and reflects the light beam again, converting it into left-handed circularly polarized light. This light is then reflected again from point D into the polarizing plate 201. This process repeats until the light beam leaves the liquid crystal waveguide coupling input device 200 and continues to propagate in the waveguide substrate 100. Thus, large-area coupling input can be achieved by utilizing the polarization of light. The overall structure is simple and the manufacturing cost is low.
[0033] By setting a dual-layer coupling input device 200, the light beam emitted from the phase source 300 passes through the polarizing waveplate 201 and enters the liquid crystal grating 202 in either left-handed or right-handed circularly polarized state. The liquid crystal grating 202 reflects the light beam and changes its polarization state. The light beam re-enters the polarizing waveplate 201 and is reflected by the waveguide substrate 100, passing through the polarizing waveplate 201 again before entering the liquid crystal grating 202. At this time, the polarization state of the light beam entering the liquid crystal grating 202 changes back to the initial state, thus preventing coupling out when entering the liquid crystal grating 202. The light beam can be reflected again by the liquid crystal grating 202 and enter the waveguide substrate 100 for transmission until it finally leaves the liquid crystal waveguide coupling input device 200 and continues to transmit in the waveguide substrate 100. It can be seen that the state of the light beam is the same each time it enters the polarizing waveplate 201. Therefore, the area of the liquid crystal waveguide coupling input device 200 can be set large enough to meet the requirements of large-area coupling input.
[0034] A second aspect of this utility model provides an augmented reality display device, such as... Figure 4 As shown, it includes: a waveguide substrate 100 for propagating the light beam generated by the phase source 300; a liquid crystal waveguide coupling input device 200 as described in the first aspect, the liquid crystal waveguide coupling input device 200 being disposed on a first side of the waveguide substrate 100; and a coupling output device 400 disposed on a second side of the waveguide substrate 100 for coupling and outputting the light beam; the light beam is emitted from the phase source 300, passes through the waveguide substrate 100, enters the liquid crystal waveguide coupling input device 200 for coupling input processing, propagates from the waveguide substrate 100 to the coupling output device 400, and then undergoes coupling output processing by the coupling output device 400 before being transmitted to the human eye.
[0035] The augmented reality display device can be, for example, an in-vehicle head-up display or AR glasses. When the augmented reality display device is an in-vehicle head-up display, the waveguide substrate 100 is the windshield of the car. When the augmented reality display device is AR glasses, the waveguide substrate 100 is the lens of the AR glasses. The reflection angle of the light beam when it propagates in the waveguide substrate 100 is greater than the total reflection angle so that it is transmitted by total reflection in the waveguide substrate 100.
[0036] The above embodiments only illustrate several implementation methods of this utility model, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the utility model patent. It should be noted that for those skilled in the art, several modifications and improvements can be made without departing from the concept of this utility model. These are all equivalent modifications and improvements made to the above embodiments based on the essential technology of this utility model, and all of these fall within the protection scope of this utility model.
Claims
1. A liquid crystal waveguide coupled input device, characterized in that, include: A polarizing plate is used to attach to the waveguide substrate to change the polarization state of a light beam. A liquid crystal grating supported on the polarizing waveplate is used to reflect the light beam back to the polarizing waveplate and change the polarization state of the light beam; After the light beam is emitted from the phase source, it passes through the waveguide substrate and enters the polarizing plate with an initial polarization state. It then enters the liquid crystal grating and is reflected back to the polarizing plate by the liquid crystal grating, where its polarization state changes once. After being reflected again by the waveguide substrate, it enters the polarizing plate again, causing a second polarization state change. This ensures that the polarization state of the light beam when it enters the liquid crystal grating is the same as its initial state, until it finally leaves the liquid crystal waveguide coupling input device and continues to propagate along the waveguide substrate.
2. The liquid crystal waveguide coupled input device according to claim 1, characterized in that, After passing through the polarizing plate and being reflected back to the liquid crystal grating by the waveguide substrate, the light beam can be converted from left-handed circularly polarized light to right-handed circularly polarized light, or from right-handed circularly polarized light to left-handed circularly polarized light.
3. The liquid crystal waveguide coupled input device according to claim 2, characterized in that, The liquid crystal grating can convert right-hand circularly polarized light into left-hand circularly polarized light, or vice versa, and the conversion direction of the liquid crystal grating is opposite to that of the polarizing plate.
4. An augmented reality display device, characterized in that, include: A waveguide substrate layer is used to propagate the light beam generated by the phase source; The liquid crystal waveguide coupled input device as described in any one of claims 1-3, wherein the liquid crystal waveguide coupled input device is disposed on the first side of the waveguide substrate layer; A coupling output device is disposed on the second side of the waveguide substrate layer and is used to couple and output the light beam. After being emitted from the phase source, the light beam passes through the waveguide substrate and enters the liquid crystal waveguide coupling input device for coupling input processing. It then propagates from the waveguide substrate to the coupling output device, and after being coupled output by the coupling output device, it is transmitted to the human eye.
5. The augmented reality display device according to claim 4, characterized in that, The waveguide substrate is a car windshield or an AR glasses lens.
6. The augmented reality display device according to claim 5, characterized in that, The reflection angle of the light beam as it propagates in the waveguide substrate is greater than the total reflection angle to achieve full transmission in the waveguide substrate.