Light leakage adjustable near-to-eye display device

Abstract

The utility model discloses a light leakage adjustable near-to-eye display device which comprises a waveguide, an optical machine, a first electro-liquid crystal layer, a first 1 / 4 wave plate, a second 1 / 4 wave plate and a second electro-liquid crystal layer, and the optical machine, the first electro-liquid crystal layer, the first 1 / 4 wave plate, the second 1 / 4 wave plate and the second electro-liquid crystal layer are all located on the same side of the waveguide. Light reflected by the waveguide is coupled to the outside through the first 1 / 4 wave plate, the second 1 / 4 wave plate and the second electrogenerated liquid crystal layer in sequence, and light transmitted by the waveguide is coupled into human eyes. The device can be switched to a bright mode or a privacy mode, and meets the use requirements of different scenes.

Description

Technical Field

[0001] This utility model belongs to the field of near-eye display technology, specifically relating to a near-eye display device with adjustable light leakage. Background Technology

[0002] In recent years, Augmented Reality (AR) technology has been applied and rapidly developed in smart wearable devices. Smart wearable devices have high requirements for thinness and lightness, making waveguide solutions the preferred choice for lightweight AR glasses. However, waveguide solutions suffer from severe frontal light leakage, a problem that cannot be solved through waveguide design alone. That is, all existing waveguide solutions exhibit frontal light leakage, posing a risk of information leakage. This is because, during the finite element time-domain differential design of waveguides, diffracted light exists at different levels. For example, if +1st-order diffraction is required, there will be a -1st-order diffraction with similar energy. The two diffractions propagate in opposite directions; one enters the human eye, and the other propagates to the outside world.

[0003] Therefore, on the one hand, light leakage from the front of the waveguide in head-mounted displays is one of the main defects in wearable smart device display technology, especially common in diffractive waveguide solutions. Light leakage can lead to privacy breaches, as the virtual image inside the glasses may be leaked into the external environment, allowing observers to see the content displayed on the user's glasses screen, such as during indoor face-to-face conversations or teleprompters. External light entering the glasses can also reduce the contrast of the virtual image, affecting user privacy, visual experience, and operational accuracy. On the other hand, some scenarios do not require information security, and transmittance can be more lenient, such as outdoor navigation. In summary, current technology lacks an adjustable solution for switching between these two scenarios on the same pair of glasses. Utility Model Content

[0004] The purpose of this invention is to address the above-mentioned problems by proposing a near-eye display device with adjustable light leakage, which can be switched between bright mode and privacy mode to meet the needs of different scenarios.

[0005] To achieve the above objectives, the technical solution adopted by this utility model is as follows:

[0006] The present invention proposes a near-eye display device with adjustable light leakage, comprising a waveguide, an optomechanical system, a first electroluminescent liquid crystal layer, a first quarter-wave plate, a second quarter-wave plate, and a second electroluminescent liquid crystal layer, all located on the same side of the waveguide. Light emitted from the optomechanical system enters the waveguide through the first electroluminescent liquid crystal layer, and light reflected from the waveguide is coupled out to the outside world through the first quarter-wave plate, the second quarter-wave plate, and the second electroluminescent liquid crystal layer in sequence. Light transmitted through the waveguide is coupled into the human eye.

[0007] Preferably, the thickness of the first electroluminescent liquid crystal layer and the second electroluminescent liquid crystal layer is 20μm to 500μm, and the response wavelength is 380nm to 780nm.

[0008] Preferably, the first quarter-wave plate is used to convert linearly polarized light into circularly polarized light, and the second quarter-wave plate is used to convert circularly polarized light into linearly polarized light.

[0009] Preferably, the thickness of the first quarter waveplate and the second quarter waveplate is 10 μm to 100 μm, and the response wavelength is 380 nm to 780 nm.

[0010] Preferably, the first electroluminescent liquid crystal layer is attached to the light-emitting side of the optomechanical system.

[0011] Preferably, the waveguide is further provided with a protective shell, with the first quarter waveplate and the second quarter waveplate located on both sides of the protective shell, respectively.

[0012] Preferably, both the first quarter-wave plate and the second quarter-wave plate are attached to the protective shell, and the second electroluminescent liquid crystal layer is attached to the second quarter-wave plate.

[0013] Preferably, the waveguide is a surface relief waveguide, a volume holographic waveguide, or an array waveguide.

[0014] Preferably, the optical engine is one of a DLP display, an LCOS display, a Micro OLED display, a Micro LED display, an LBS display, and an FSD display.

[0015] Compared with the prior art, the beneficial effects of this utility model are as follows:

[0016] This near-eye display device with adjustable light leakage has two adjustable modes: a bright mode and a privacy mode. Specifically, the device includes a waveguide, an optomechanical system, a first electroluminescent liquid crystal layer, a first quarter-wave plate, a second quarter-wave plate, and a second electroluminescent liquid crystal layer, all located on the same side of the waveguide. The first electroluminescent liquid crystal layer is disposed on the light-emitting side of the optomechanical system, and the first quarter-wave plate, second quarter-wave plate, and second electroluminescent liquid crystal layer are arranged sequentially away from the waveguide. When the electroluminescent liquid crystal layers are not in operation, it functions like a regular waveguide, offering high transmittance (100%) for the bright mode. When the electroluminescent liquid crystal layers are in operation, the transmittance is 50%, and the light leakage rate is <1%, achieving the privacy mode, thus meeting the needs of different usage scenarios. Attached Figure Description

[0017] Figure 1 This is a structural schematic diagram of the light leakage adjustable near-eye display device of this utility model in one application scenario;

[0018] Figure 2 This is a structural schematic diagram of the near-eye display device with adjustable light leakage in a second application scenario.

[0019] Figure 3 This is a schematic diagram illustrating the light conversion principle of the adjustable light leakage near-eye display device of this utility model.

[0020] Explanation of reference numerals in the attached drawings: 1. Optomechanical; 2. First electroluminescent liquid crystal layer; 3. First quarter-wave plate; 4. Second quarter-wave plate; 5. Second electroluminescent liquid crystal layer; 6. Waveguide; 7. Protective shell. Detailed Implementation

[0021] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0022] It should be noted that when a component is referred to as being "connected" to another component, it can be directly connected to the other component or there may be an intervening component. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of the application.

[0023] like Figure 1-3 As shown, a near-eye display device with adjustable light leakage includes a waveguide 6, an optomechanical system 1, a first electro-liquid crystal layer 2, a first quarter-wave plate 3, a second quarter-wave plate 4, and a second electro-liquid crystal layer 5, all located on the same side of the waveguide 6. Light emitted from the optomechanical system 1 enters the waveguide 6 through the first electro-liquid crystal layer 2. Light reflected from the waveguide 6 is coupled out to the outside through the first quarter-wave plate 3, the second quarter-wave plate 4, and the second electro-liquid crystal layer 5 in sequence. Light transmitted through the waveguide 6 is coupled into the human eye.

[0024] The near-eye display device with adjustable light leakage employs a liquid crystal polarization architecture. Specifically, a first electroluminescent liquid crystal layer 2 is disposed on the light-emitting side of the optical engine 1. The optical engine 1, the first electroluminescent liquid crystal layer 2, the first quarter-wave plate 3, the second quarter-wave plate 4, and the second electroluminescent liquid crystal layer 5 are all located on the same side of the waveguide 6. The first quarter-wave plate 3, the second quarter-wave plate 4, and the second electroluminescent liquid crystal layer 5 are arranged sequentially in a direction away from the waveguide 6. The optical engine 1 can be positioned at any angle relative to the waveguide 6, but is preferably perpendicular to the waveguide 6. The operation of the electroluminescent liquid crystal layer mainly relies on the rotational characteristics of liquid crystal molecules and the selective light transmission capability of the polarizing film. Under the influence of an electric field, the liquid crystal molecules rotate, allowing light from a specific direction to pass through while blocking light from other directions, thus converting natural light into linearly polarized light. This technology is well-known to those skilled in the art and will not be described in detail here.

[0025] Specifically, when the electrochromic liquid crystal layer is not subjected to voltage, it is in a transparent state, meaning it is inactive. The optomechanical system 1 emits natural light, which passes through a quarter-wave plate without any change in polarization. Since the quarter-wave plate is transparent, each quarter-wave plate is also inactive, resulting in a state equivalent to the original waveguide, thus producing light leakage for information display. When the electrochromic liquid crystal layer is subjected to voltage, it begins to function. The light from the optomechanical system 1 passes through the first electrochromic liquid crystal layer 2, becoming vertically polarized light with 50% transmittance. This light then passes sequentially through the first quarter-wave plate 3 and the second quarter-wave plate 4, becoming horizontally polarized light, which is absorbed by the second electrochromic liquid crystal layer 5. The light leakage rate is less than 1%, achieving information privacy while maintaining 50% transmittance for external observation. Figure 3 As shown, the optomechanical system 1 generates 0° linearly polarized light (L1) through the first electro-liquid layer 2 in its operating state. The 0° linearly polarized light passes through the first quarter-wave plate 3 and becomes left-handed circularly polarized light (L2). The left-handed circularly polarized light then passes through the second quarter-wave plate 4 and becomes 90° linearly polarized light (L3). The 90° linearly polarized light (L3) can be absorbed by the second electro-liquid layer 5. The light paths in each figure are for illustrative purposes only.

[0026] This near-eye display device with adjustable light leakage adopts a liquid crystal polarization architecture to achieve adjustable privacy mode and bright mode. The privacy mode has a transmittance of 50% and a light leakage rate of <1%; the bright mode has a transmittance of 100%. Both the light leakage rate in privacy mode and the transmittance in bright mode are excellent.

[0027] In one embodiment, the thickness of the first electroluminescent liquid crystal layer 2 and the second electroluminescent liquid crystal layer 5 is 20 μm to 500 μm, and the response wavelength is 380 nm to 780 nm. This allows for complete coverage of visible light, meeting the needs of human vision and facilitating processing and assembly.

[0028] In one embodiment, a first quarter-wave plate 3 is used to convert linearly polarized light into circularly polarized light, and a second quarter-wave plate 4 is used to convert circularly polarized light into linearly polarized light.

[0029] In one embodiment, the thickness of the first quarter-wave plate 3 and the second quarter-wave plate 4 is 10 μm to 100 μm, and the response wavelength is 380 nm to 780 nm. This allows for complete coverage of visible light, meeting the needs of human vision and facilitating processing and assembly.

[0030] In one embodiment, the first electroluminescent liquid crystal layer 2 is attached to the light-emitting side of the optomechanical system 1. This facilitates installation.

[0031] In one embodiment, the waveguide 6 is further provided with a protective shell 7, with the first quarter waveplate 3 and the second quarter waveplate 4 located on opposite sides of the protective shell 7. The protective shell 7 protects the working surface of the waveguide 6, which helps to extend its service life, and can also be used to fix the first quarter waveplate 3 and the second quarter waveplate 4, etc.

[0032] In one embodiment, both the first quarter-wave plate 3 and the second quarter-wave plate 4 are attached to the protective shell 7, and the second electroluminescent liquid crystal layer 5 is attached to the second quarter-wave plate 4. This attachment method is convenient for processing.

[0033] In one embodiment, waveguide 6 is a surface relief waveguide, a volume holographic waveguide, or an array waveguide. The specific waveguide type can be selected according to actual needs.

[0034] In one embodiment, the optical engine 1 is one of a DLP display, an LCOS display, a Micro OLED display, a Micro LED display, an LBS display, and an FSD display.

[0035] Among them, the optical engine 1, as the core component of near-eye display technology, directly affects the final display effect, size, and user experience. For example, a Micro OLED display or a Micro LED display is preferred, as it has high brightness and high contrast characteristics, and the resolution can be improved by reducing the pixel size while reducing power consumption, thus meeting the lightweight requirements of AR / VR devices. It is easy to understand that those skilled in the art are not limited to the display types listed above, and can also select the model according to actual needs.

[0036] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0037] The embodiments described above are merely specific and detailed examples of the embodiments described in this application, and should not be construed as limiting the scope of the application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these modifications and improvements all fall within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the appended claims.

Claims

1. A near-eye display device with adjustable light leakage, characterized in that: The light leakage adjustable near-eye display device includes a waveguide (6), an optomechanical system (1), a first electro-liquid crystal layer (2), a first quarter wave plate (3), a second quarter wave plate (4), and a second electro-liquid crystal layer (5), all located on the same side of the waveguide (6). The light emitted by the optomechanical system (1) enters the waveguide (6) through the first electro-liquid crystal layer (2). The light reflected by the waveguide (6) is coupled out to the outside through the first quarter wave plate (3), the second quarter wave plate (4), and the second electro-liquid crystal layer (5) in sequence. The light transmitted by the waveguide (6) is coupled into the human eye.

2. The near-eye display device with adjustable light leakage as described in claim 1, characterized in that: The thickness of the first electro-liquid layer (2) and the second electro-liquid layer (5) is 20μm to 500μm, and the response wavelength is 380nm to 780nm.

3. The near-eye display device with adjustable light leakage as described in claim 1, characterized in that: The first quarter-wave plate (3) is used to convert linearly polarized light into circularly polarized light, and the second quarter-wave plate (4) is used to convert circularly polarized light into linearly polarized light.

4. The near-eye display device with adjustable light leakage as described in claim 1, characterized in that: The thickness of the first quarter wave plate (3) and the second quarter wave plate (4) is 10 μm to 100 μm, and the response band is 380 nm to 780 nm.

5. The near-eye display device with adjustable light leakage as described in claim 1, characterized in that: The first electroluminescent liquid crystal layer (2) is attached to the light-emitting side of the optomechanical system (1).

6. The near-eye display device with adjustable light leakage as described in claim 1, characterized in that: The waveguide (6) is also provided with a protective shell (7), and the first quarter wave plate (3) and the second quarter wave plate (4) are located on both sides of the protective shell (7).

7. The near-eye display device with adjustable light leakage as described in claim 6, characterized in that: The first quarter-wave plate (3) and the second quarter-wave plate (4) are both attached to the protective shell (7), and the second electro-liquid layer (5) is attached to the second quarter-wave plate (4).

8. The near-eye display device with adjustable light leakage as described in claim 1, characterized in that: The waveguide (6) can be a surface relief waveguide, a volume holographic waveguide, or an array waveguide.

9. The near-eye display device with adjustable light leakage as described in claim 1, characterized in that: The optical engine (1) is one of the following: DLP display, LCOS display, Micro OLED display, Micro LED display, LBS display and FSD display.

Images