Liquid crystal optical waveguide coupling output device and augmented reality display device
By using a combination structure of polarizing waveplate and liquid crystal grating in the liquid crystal coupled output device, the problem of energy uniformity was solved, and uniform output of beam energy at different positions was achieved, simplifying the processing and reducing costs.
Patent Information
- Application Number
- CN202423197742.6
- 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 output devices have problems with energy uniformity. The energy of the light beam gradually decreases during propagation, resulting in different brightness levels of the pattern observed by the observer at different positions. Existing solutions require the device to be processed in multiple regions, which increases the difficulty and cost.
By employing a structure in which a first polarizing waveplate and a second polarizing waveplate are sequentially bonded to a liquid crystal grating, the proportion of the light beam entering the liquid crystal grating in the first polarized state is increased through polarization state transition, thereby improving diffraction efficiency and ensuring uniformity of coupled output energy at different positions.
It achieves uniformity of beam energy without partitioning, simplifies the processing, and reduces costs.
Smart Images
Figure CN223501270U_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 output 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] Currently, liquid crystal coupled output devices (LCDs) face the problem of energy uniformity. Specifically, the energy of a light beam gradually decreases as it propagates within the LCD. Assuming that 10% of the energy is coupled out each time, the energy that continues to propagate after the first coupling out accounts for 90% of the total energy, the energy coupled out the second time is only 9%, the energy that continues to propagate after the second coupling out accounts for 81% of the total energy, and the energy coupled out the third time is only 8.1%. As the number of coupling outs increases, the coupled energy gradually decreases. The different coupled energy each time causes the observer to observe different levels of brightness of the pattern at different positions.
[0004] Existing solutions typically involve etching the liquid crystal grating to adjust its thickness at various locations, thereby altering the diffraction efficiency at different positions and ensuring that the coupled energy is nearly identical. For example... Figure 1 As shown, the more reflections, the less energy remains, and the greater the thickness of the corresponding position on the liquid crystal grating, resulting in higher diffraction efficiency at different positions. The coupled energy equals the remaining energy multiplied by the diffraction efficiency, thus ensuring that the coupled energy at different positions on the liquid crystal grating is essentially the same. However, this approach requires dividing the coupling output device into several regions, each requiring different processing methods, making the overall processing more difficult and costly. Utility Model Content
[0005] In order to overcome the shortcomings of the prior art, the purpose of this utility model is to provide a liquid crystal optical waveguide coupling output device and an augmented reality display device, which has the advantages of making the coupled energy more uniform and the implementation method simpler.
[0006] The objective of this utility model is achieved through the following technical solution:
[0007] According to a first aspect of the present disclosure, a liquid crystal waveguide coupled output device is provided, comprising a first polarizing waveplate, a second polarizing waveplate, and a liquid crystal grating sequentially bonded together. The first polarizing waveplate is bonded to a waveguide substrate layer, and the liquid crystal grating is used to diffract and couple a first polarized beam. The first polarizing waveplate is bonded to the waveguide substrate layer, and the first and second polarizing waveplates are used to perform polarization state conversion on a second polarized beam transmitted from the waveguide substrate layer, so as to increase the proportion of the first polarized beam incident on the liquid crystal grating after each passage through the first and second polarizing waveplates, thereby improving diffraction efficiency. The first polarization state is opposite to the second polarization state.
[0008] To achieve the above technical solution, the light beam is transmitted to the coupling output device via the waveguide substrate. Initially, the light beam is in a second polarization state, while the liquid crystal grating only affects the first polarization state. The second polarization state light beam sequentially enters the first polarization waveplate and the second polarization waveplate, which transform the polarization state of the second polarization state light beam, increasing the proportion of the first polarization state light beam when it enters the liquid crystal grating. Then, the liquid crystal grating performs diffraction coupling and outputs the beam. After passing through the second polarization waveplate, the first polarization waveplate, and the waveguide substrate in sequence, the beam enters the human eye. Simultaneously, the light beam continues to propagate forward along the waveguide substrate. During the propagation process, the first polarization waveplate and the second polarization waveplate again increase the proportion of the first polarization state light beam until it finally leaves the coupling output device. As the remaining energy of the light beam in the coupling output device gradually decreases, but the proportion of the first polarization state light beam increases, the diffraction efficiency gradually increases. The coupled output energy equals the remaining energy multiplied by the diffraction efficiency, thus ensuring that the coupled output energy at different positions remains consistent, thereby guaranteeing the uniformity of the emitted energy. This achieves uniform coupled output without partitioning, making the implementation simpler and more convenient.
[0009] In some exemplary embodiments, the first polarization beam is left-handed or right-handed circularly polarized light, and the second polarization beam is right-handed or left-handed circularly polarized light with the polarization state opposite to that of the first polarization beam.
[0010] In some exemplary embodiments, when the first polarizing plate and the second polarizing plate perform polarization state conversion on the light beam, the product of the diffraction efficiency corresponding to the proportion of the generated first polarized light beam and the residual energy coupled out by the liquid crystal grating is kept within a predetermined deviation range.
[0011] According to a second aspect of the present disclosure, an augmented reality display device is provided, comprising:
[0012] A waveguide substrate layer is used to propagate the light beam generated by the phase source;
[0013] A coupling input device is disposed on the first side of the waveguide substrate layer and is used to perform coupling input processing on the beam input from the phase source;
[0014] The liquid crystal waveguide coupled output device as described in the first aspect is disposed on the second side of the waveguide substrate layer and is used to couple and output a light beam.
[0015] After the light beam is emitted from the phase source, it passes through the waveguide substrate and enters the coupling input device for coupling input processing. It then propagates from the waveguide substrate to the liquid crystal waveguide coupling output device, where it undergoes coupling output processing to ensure that the energy of each coupling output is kept within a predetermined deviation range before being transmitted to the human eye.
[0016] In some exemplary embodiments, the waveguide substrate is a car windshield or an AR glasses lens.
[0017] 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.
[0018] In summary, compared with the prior art, this utility model has the following beneficial effects:
[0019] This invention provides a liquid crystal waveguide coupling output device and an augmented reality display device. A light beam is transmitted to the coupling output device via a waveguide substrate. Initially, the beam is in a second polarization state, while the liquid crystal grating only affects the first polarization state beam. The second polarization state beam sequentially enters a first polarizing waveplate and a second polarizing waveplate, which perform polarization state transformation on the second polarization state beam, increasing the proportion of the first polarization state beam entering the liquid crystal grating. The liquid crystal grating then performs diffraction coupling output, and the beam sequentially passes through the second polarizing waveplate, the first polarizing waveplate, and the waveguide substrate before entering the human eye. The beam continues to propagate forward along the waveguide substrate. During this propagation, the proportion of the first polarized beam is further increased by the first and second polarization waveplates until it eventually detaches from the coupling output device. As the remaining energy of the beam in the coupling output device gradually decreases, but the proportion of the first polarized beam increases, the diffraction efficiency gradually increases. The coupled output energy equals the remaining energy multiplied by the diffraction efficiency, thus ensuring that the coupled output energy at different locations remains consistent. This guarantees the uniformity of the emitted energy and achieves uniform coupled output without partitioning, making the implementation simpler and more convenient. Attached Figure Description
[0020] Figure 1 This is a schematic diagram of the structure of a liquid crystal coupled output device in the background art.
[0021] Figure 2This is a schematic diagram of the structure of the liquid crystal waveguide coupled output device in the embodiment of this utility model.
[0022] Figure 3 This is a schematic diagram of the augmented reality display device in an embodiment of the present invention.
[0023] The numbers and letters in the diagram represent the names of the corresponding components:
[0024] 100 Waveguide substrate; 200 Coupled input device; 300 Phase source; 400 Coupled output device; 401 First polarizing waveplate; 402 Second polarizing waveplate; 403 Liquid crystal grating. Detailed Implementation
[0025] 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.
[0026] like Figure 2 As shown, a first aspect of this utility model provides a liquid crystal waveguide coupling output device 400, including a first polarizing waveplate 401, a second polarizing waveplate 402, and a liquid crystal grating 403 sequentially bonded together. The first polarizing waveplate 401 is bonded to a waveguide substrate 100, and the liquid crystal grating 403 is used to diffract and couple a first polarized beam. The first polarizing waveplate 401 is bonded to the waveguide substrate 100, and the first polarizing waveplate 401 and the second polarizing waveplate 402 are used to perform polarization state conversion on a second polarized beam transmitted from the waveguide substrate 100, so as to increase the proportion of the first polarized beam entering the liquid crystal grating 403 after each passage through the first polarizing waveplate 401 and the second polarizing waveplate 402, thereby improving diffraction efficiency. The first polarization state is opposite to the second polarization state.
[0027] The orientation and phase delay of the first polarizing waveplate 401 and the second polarizing waveplate 402 can be obtained by optimizing the fiber optic trajectory using appropriate software. The dimensions of the first polarizing waveplate 401, the second polarizing waveplate 402, and the liquid crystal grating 403 are determined in combination with the thickness of the waveguide substrate 100 to be applied. The first polarized beam is either left-handed or right-handed circularly polarized light, and the second polarized beam is either right-handed or left-handed circularly polarized light with the opposite polarization state to the first polarized beam. When the first polarizing waveplate 401 and the second polarizing waveplate 402 convert the polarization state of the beam, the product of the diffraction efficiency corresponding to the proportion of the generated first polarized beam and the residual energy coupled out by the liquid crystal grating 403 is kept within a predetermined deviation range. The waveguide substrate 100, the first polarizing waveplate 401, the second polarizing waveplate 402, and the liquid crystal grating 403 can all be fixed together by optical adhesive.
[0028] When the liquid crystal grating 403 only works on left-handed circularly polarized light, the light beam initially transmitted from the waveguide substrate 100 is controlled to be right-handed circularly polarized light. At this time, the polarization state of the light beam changes each time it passes through the waveplate layer composed of the first polarizing waveplate 401 and the second polarizing waveplate 402. Through the design of the waveplate layer, the proportion of left-handed circularly polarized light can be gradually increased each time it enters the polarization grating. When the number of coupling out is small, the remaining energy of the light beam is large, but the proportion of left-handed circularly polarized light is small, resulting in low diffraction efficiency. Conversely, if the number of coupling out is large, the remaining energy of the light beam is small, but the proportion of left-handed circularly polarized light is large, resulting in high diffraction efficiency. Since the coupled energy is equal to the remaining energy multiplied by the diffraction efficiency, no matter how many times it is coupled out, the final coupled energy will remain basically equal, that is, within the predetermined deviation range, so that the emitted energy can remain uniform.
[0029] Conversely, when the liquid crystal grating 403 only acts on right-hand circularly polarized light, the beam initially transmitted from the waveguide substrate 100 is controlled to be left-hand circularly polarized light. At this time, the polarization state of the beam changes each time it passes through the waveplate layer composed of the first polarizing waveplate 401 and the second polarizing waveplate 402. Through the design of the waveplate layer, the proportion of right-hand circularly polarized light can be gradually increased each time it enters the polarization grating. When the number of couplings is small, the beam has more remaining energy, but the proportion of right-hand circularly polarized light is small, resulting in lower diffraction efficiency. Conversely, if the number of couplings is large, the beam has less remaining energy, but the proportion of right-hand circularly polarized light is large, resulting in higher diffraction efficiency. Since the coupled energy is equal to the remaining energy multiplied by the diffraction efficiency, no matter how many couplings there are, the final coupled energy will remain basically equal, that is, within the predetermined deviation range, thereby ensuring that the emitted energy remains uniform.
[0030] Therefore, in this invention, the light beam is transmitted to the coupling output device 400 via the waveguide substrate 100. Initially, the light beam is in a second polarization state, while the liquid crystal grating 403 only affects the first polarization state light beam. The second polarization state light beam sequentially enters the first polarization plate 401 and the second polarization plate 402. The first polarization plate 401 and the second polarization plate 402 perform polarization state transformation on the second polarization state light beam, increasing the proportion of the first polarization state light beam when it enters the liquid crystal grating 403. Then, the liquid crystal grating 403 performs diffraction coupling and outputs the light beam. After passing through the second polarization plate 402, the first polarization plate 401, and the waveguide substrate 100 in sequence, the light beam enters the human eye. The beam will continue to propagate forward along the waveguide substrate 100. During the propagation process, the proportion of the first polarized beam will be increased by the first polarization plate 401 and the second polarization plate 402 until it finally detaches from the coupling output device 400. As the remaining energy of the beam in the coupling output device 400 gradually decreases, but the proportion of the first polarized beam increases, the diffraction efficiency gradually increases. The coupled output energy is equal to the remaining energy multiplied by the diffraction efficiency, which ensures that the coupled output energy at different positions remains consistent, thereby ensuring the uniformity of the emitted energy. This achieves uniform coupled output without partitioning, making the implementation simpler and more convenient.
[0031] A second aspect of this utility model provides an augmented reality display device, such as... Figure 3 As shown, it includes: a waveguide substrate 100 for propagating the light beam generated by the phase source 300; a coupling input device 200 disposed on a first side of the waveguide substrate 100 for coupling input processing of the light beam input from the phase source 300; and a liquid crystal waveguide coupling output device 400 as described in the first aspect, disposed on a second side of the waveguide substrate 100 for coupling output of the light beam; the light beam is emitted from the phase source 300, passes through the waveguide substrate 100, enters the coupling input device 200 for coupling input processing, propagates from the waveguide substrate 100 to the liquid crystal waveguide coupling output device 400, and is coupled output by the liquid crystal waveguide coupling output device 400 so that the energy of each coupled output is kept within a predetermined deviation range before being transmitted to the human eye.
[0032] 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 can be transmitted by total reflection in the waveguide substrate 100.
[0033] 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 output device, characterized in that, The device includes a first polarizing waveplate, a second polarizing waveplate, and a liquid crystal grating, which are sequentially bonded together. The first polarizing waveplate is bonded to the waveguide substrate, and the liquid crystal grating is used to diffract and couple a first polarized beam into the output. The first polarizing waveplate is bonded to the waveguide substrate, and the first and second polarizing waveplates are used to perform polarization state transformation on a second polarized beam transmitted from the waveguide substrate, so as to increase the proportion of the first polarized beam entering the liquid crystal grating after each passage through the first and second polarizing waveplates, thereby improving diffraction efficiency. The first polarization state is opposite to the second polarization state.
2. The liquid crystal waveguide coupled output device according to claim 1, characterized in that, The first polarization beam is either left-handed or right-handed circularly polarized light, and the second polarization beam is either right-handed or left-handed circularly polarized light with the opposite polarization state to the first polarization beam.
3. The liquid crystal waveguide coupled output device according to claim 2, characterized in that, When the first polarizing plate and the second polarizing plate perform polarization state conversion on the light beam, the product of the diffraction efficiency corresponding to the proportion of the generated first polarized light beam and the residual energy coupled out by the liquid crystal grating is kept within a predetermined deviation range.
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; A coupling input device is disposed on the first side of the waveguide substrate layer and is used to perform coupling input processing on the beam input from the phase source; The liquid crystal waveguide coupled output device as described in any one of claims 1-3 is disposed on the second side of the waveguide substrate layer and is used to couple and output a light beam; After the light beam is emitted from the phase source, it passes through the waveguide substrate and enters the coupling input device for coupling input processing. It then propagates from the waveguide substrate to the liquid crystal waveguide coupling output device, where it undergoes coupling output processing to ensure that the energy of each coupling output is kept within a predetermined deviation range before being 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.