An attitude recognition device based on a liquid crystal functional film and application thereof

Abstract

This invention relates to the field of G06F3 / 01, and more particularly to a posture recognition device based on a liquid crystal functional film and its application. The posture recognition device based on a liquid crystal functional film comprises an encoding layer group, an infrared emitting group, and at least one infrared receiving group; the encoding layer group includes a reflective layer and an encoding layer having at least two different optical anisotropy regions; the infrared emitting group includes an infrared emitter and a polarizing layer; the infrared receiving group includes an infrared receiver and a polarizing layer. The posture recognition device of this invention has excellent human-computer interaction posture recognition performance, effectively increases the recognition distance, reduces interference with the image, and can simultaneously recognize position and rotation information, thus achieving posture recognition and possessing broad development prospects.

Description

Technical Field

[0001] This invention relates to the field of G06F3 / 01, and more particularly to a posture recognition device based on a liquid crystal functional film and its application. Background Technology

[0002] Human-computer interaction research, as the name suggests, studies the interaction between humans and machine systems. The machine can often be represented by computerized systems and software, while humans are the users of these systems and software. Human-computer interaction can effectively enhance the function of the systems and software.

[0003] In today's era of the Internet of Things, especially with the emergence of the "metaverse" concept, the importance of human-computer interaction has been further enhanced. Generally, human-computer interaction primarily utilizes commonly used devices such as mice, keyboards, touchscreens, and microphones. With the development of related disciplines, interaction methods based on voice, touch, eye tracking, gestures, and body sensing have emerged in recent years. However, regardless of the evolution of human-computer interaction methods, sensors are essential for capturing and tracking signals, and the transmission and reception of light through optical paths is a typical sensing method. Existing technology (CN100462900C) provides a simple recognition device where an image receiver directly detects the position of a light-emitting device held by the operator, thereby driving the screen to respond and complete the interaction. This device can only enable close-range interaction and can only provide positional information within a plane.

[0004] Existing technology (CN102879938A) provides a position encoding detection device for use on a display. This device includes a position recognition pattern layer that emits a second wavelength of light when excited by a first wavelength, a transmitter that emits the first wavelength of light, and an image recognizer that receives the second wavelength of light. It also includes a polarizing film assembly for filtering the display's light emission and a color filter for filtering the first wavelength of light. The device operates by emitting the first wavelength of light to the position recognition pattern layer, causing the illuminated area to emit a patterned second wavelength of light. The recognizer analyzes the position based on the received second wavelength pattern, thereby providing feedback on the transmitter's pointing position. However, this device is only suitable for providing feedback on the transmitter's pointing position and cannot provide feedback on the transmitter's axial rotation angle.

[0005] As can be seen from the above, the existing technology can only provide feedback on the pointing position of the transmitter, but cannot provide feedback on the rotation angle of the transmitter. That is, it is a planar position sensor, which limits the application of the identification device.

[0006] Therefore, there is an urgent need for a multi-degree-of-freedom attitude recognition device and method that can realize planar position recognition and rotation angle recognition. Summary of the Invention

[0007] To address the aforementioned problems, the first aspect of this invention provides a posture recognition device based on a liquid crystal functional film, the structure of which includes an encoding layer group, an infrared emitting group, and at least one infrared receiving group; the encoding layer group includes a reflective layer and an encoding layer having at least two different optical anisotropy regions; the infrared emitting group includes an infrared emitter and a polarizing layer; and the infrared receiving group includes an infrared receiver and a polarizing layer.

[0008] As a preferred embodiment, the two different optical anisotropic regions in the coding layer are optical anisotropic regions with the same horizontal phase delay and different optical axis angles.

[0009] As a more preferred embodiment, the horizontal phase delay of the two different optically anisotropic regions in the coding layer is 1 / 4 of the center output wavelength of the infrared emitter.

[0010] As a more preferred embodiment, the optical axis angle of the anisotropic region in the coding layer is ±45°.

[0011] As a preferred embodiment, the optically anisotropic regions in the coding layer constitute a resolvable pattern, and the pattern is evenly distributed; the resolvable pattern has a one-to-one corresponding positional relationship.

[0012] As a preferred embodiment, the graphic is at least one of numbers, letters, characters, shapes, and symbols.

[0013] For information on the raw materials and methods for preparing the coding layer, please refer to patent CN1054439C.

[0014] As a preferred embodiment, the thickness of the coding layer is 1.5 to 3 micrometers.

[0015] As a preferred embodiment, the reflective layer is a single infrared light reflective layer; the reflective efficiency of the reflective layer is 60-100%.

[0016] As a preferred embodiment, the reflective layer is a cholesteric liquid crystal reflective layer.

[0017] As a preferred embodiment, the reflective layer is a superposition of a levorotatory cholesteric liquid crystal reflective layer composed of a levorotatory chiral agent and a polymerizable liquid crystal, and a dextrorotatory cholesteric liquid crystal reflective layer composed of a dextrorotatory chiral agent and a polymerizable liquid crystal.

[0018] As a preferred embodiment, the thickness of both the L-cholesterol liquid crystal reflective layer and the D-cholesterol liquid crystal reflective layer of the reflective layer is 2–4 micrometers.

[0019] As a preferred embodiment, the reflective layer is a single-axis cholesteric liquid crystal reflective layer composed of two single-axis chiral agents and polymerizable liquid crystals, and a half-wave plate layer disposed therebetween.

[0020] For information on the raw materials and methods for preparing the reflective layer, please refer to patent CN107346084B.

[0021] As a preferred embodiment, the infrared emitter is a wearable infrared emitting device with adjustable position and rotatable angle.

[0022] As a preferred embodiment, the wearable infrared light-emitting device includes an infrared light-emitting diode made of a semiconductor material having a bandgap in the infrared range.

[0023] As a preferred embodiment, the semiconductor material having a bandgap in the infrared range is gallium arsenide or gallium aluminum arsenide.

[0024] As a preferred embodiment, the light emission angle of the infrared photodiode is 15–30°.

[0025] The light emission angle of the infrared LED can be adjusted by an additional lens group, including a lens group with adjustable focal length; the size of the angle can be adjusted according to the specific application scenario.

[0026] As a preferred embodiment, the wavelength of the infrared light-emitting diode is 850–980 nm.

[0027] As a preferred embodiment, the wavelength of the infrared light-emitting diode is any one of 880nm, 940nm, and 980nm.

[0028] This application does not impose any special limitation on the luminous power of the infrared LED. The luminous power of the LED can be adjusted according to the evaluation of the test environment by those skilled in the art. For example, preferably, it can be 1 to 50 mW in the near field environment; preferably, it can be 50 to 100 mW in the far field environment.

[0029] As a preferred embodiment, the polarizing layer in the infrared emitting group is at least one of a linear polarizer and a circular polarizer.

[0030] As a more preferred embodiment, the polarizing layer in the infrared emitting group is a linear polarizer.

[0031] As a more preferred embodiment, the polarizing layer and the infrared emitter in the infrared emitting group have a fixed relative position.

[0032] As a more preferred embodiment, the linear polarizer is at least one of the following: a stretched full-spectrum absorption linear polarizer, a stretched infrared absorption linear polarizer, and a coated infrared absorption linear polarizer.

[0033] Stretched full-spectrum absorption linear polarizer: Any suitable polarizer can be selected as the polarizer according to the purpose. The suitable polarizer is a dichroic substance adsorbed on a hydrophilic polymer film. Preferably, the stretched full-spectrum absorption linear polarizer is a polyvinyl alcohol film with iodine adsorbed on its surface, stretched by a single pull, with a thickness of 20-80 micrometers. Stretched polarizer products can be purchased from companies such as Sumitomo, Nitto, Suginami, and Shengbo.

[0034] Stretched infrared absorption linear polarizer: A visible-light transparent infrared polarizing layer can be used. The specific preparation method and thickness are consistent with those of the stretched full-spectrum absorption linear polarizer, except that the adsorbent material on the polyvinyl alcohol-based film surface is replaced with an infrared dichroic dye. Preferably, the infrared dichroic dye is at least one of the following: cyanine dichroic dyes DLS 880B, DLS-905A, DLS-908B, DLS-910B, DLS-911A, DLS-912C, DLS-963B, DLS-1001A, and DLS-1003A sold by Crystal-Lyn Chemicals; and dithioene nickel-based dichroic dyes Epo3116, Epo3138, Epo3072, and dithioene palladium-based dichroic dye Epo4105 sold by Epolin Chemicals.

[0035] Coated infrared absorption linear polarizer: The thickness of the coated infrared absorption linear polarizer is 0.5 to 5 micrometers, and more preferably 1 to 3.5 micrometers.

[0036] As a preferred embodiment, the method for preparing the coating-type infrared absorption linear polarizer includes: a step of coating a composition comprising a non-coloring polymerizable liquid crystal compound and a dichroic compound onto the surface of a substrate, an alignment film, or a protective layer to form a coating film; and a step of polymerizing the aforementioned non-coloring polymerizable liquid crystal compound.

[0037] Preferably, the non-coloring polymerizable liquid crystal compound is polymerized in an oriented state, particularly in a horizontal orientation relative to the protective layer. Furthermore, when the above-mentioned composition for forming an infrared-absorbing linear polarizer using the coating method contains a solvent, a step of drying the coating film may be included as needed; examples of drying methods include natural drying, ventilation drying, heating drying, and reduced pressure drying.

[0038] Circular polarizer: The circular polarizer is prepared by adding a 1 / 4 wave plate with an optical axis angle of ±45° to the stretching full-spectrum absorption linear polarizer, stretching infrared absorption linear polarizer, and coating infrared absorption linear polarizer described above.

[0039] The method for preparing the waveplate can be found in patents CN1022276578, CN102257412A, US20080291389, and CN100406928C.

[0040] As a preferred embodiment, the infrared receiving group and the infrared emitting group are independent of each other.

[0041] As a preferred embodiment, the infrared receiver of the infrared receiver group is preferably an infrared CCD camera receiver; the infrared CCD camera receiver includes an indium gallium arsenide or mercury cadmium telluride detector; the infrared CCD camera receiver also includes a light filter that filters out light wavelengths other than infrared wavelengths in this application.

[0042] As a preferred embodiment, the polarizing layer of the infrared receiving group is the same as the polarizing layer of the infrared emitting group.

[0043] A second aspect of the present invention provides an application of the above-mentioned posture recognition device based on liquid crystal functional film, including the application of the posture recognition device in posture recognition in human-computer interaction.

[0044] As a preferred option, this includes the application of the posture recognition device in human-computer interaction with a display.

[0045] As a preferred option, this includes the application of the posture recognition device in human-computer interaction of AR devices.

[0046] The attitude recognition system based on a liquid crystal functional film provided in this application has excellent information feedback performance, and is not limited to position information. The applicant believes that, as indicated in the appendix to the specification… Figure 1For example, in the coding layer, the horizontal phase delay of the background and pattern B3 is 1 / 4 of the center output wavelength of the infrared emitter, with optical axis directions of 0° and 45° respectively. Because the coding layer and reflective layer are transparent under visible light, the coded information cannot be recognized by the naked eye regardless of whether it is illuminated by infrared light, nor will it interfere with the observation of information located behind the coding layer and reflective layer. Linearly polarized light emitted from the infrared emitter at an angle of θ passes through the coding layer, is reflected by the reflective layer, and then passes through the coding layer again, its polarization angle changing to -θ and 90°-θ. The reflected light continues to pass through the polarization layer of the infrared receiver group, generating contrast and being recognized by the infrared receiver. When the infrared emitter group rotates (θ changes), the contrast of the pattern received by the infrared receiver will change, and the contrast is a function of θ, thus allowing the determination of the angle of the infrared emitter group. When the infrared emitter group changes position, the pattern received by the infrared receiver will change, thus allowing the determination of the position of the infrared emitter group.

[0047] Beneficial effects:

[0048] 1. The posture recognition device provided in this application can test the liquid crystal functional film by receiving and recognizing the polarized light converted from the reflection of infrared light. It effectively realizes the position and rotation information of the positioning code at a long distance, realizes the dual feedback of the position and rotation information of the light emitter, and can judge the overall state of the light emitter in multiple dimensions, thereby performing effective posture recognition.

[0049] 2. The posture recognition device provided in this application can significantly reduce the thickness of each layer. The overall coding layer group can be made thinner and can be effectively applied to flexible panels, further expanding the applicability of the posture recognition device. On the other hand, the high transparency of the coding layer group can not affect the appearance of the object being attached, and will not affect the normal use of the object being attached.

[0050] 3. The posture recognition device provided in this application of the present invention has a coding layer group in which the reflective layer and the coding layer do not absorb or reflect visible light, thus having excellent visible light transmittance and not losing the overall visible brightness of the loaded display or screen.

[0051] 4. The posture recognition device provided in this invention application has a receiver that is independent of the emitter, so that rotation information can be recorded; otherwise, if the receiver rotates with the emitter, it cannot be recognized. Furthermore, multiple receivers can be set up and placed in different positions to enhance recognition accuracy. Attached Figure Description

[0052] Figure 1 This is a schematic diagram illustrating the working principle of the posture recognition device of this application.

[0053] Figure 2This is a schematic diagram of the working structure of the posture recognition device of this application.

[0054] Figure 3 This is a schematic diagram of the application structure described in Embodiment 3 of this application.

[0055] In the diagram: 1-Infrared emitter, 2-Infrared light, 3-Polarizing layer, 4-Encoding layer, 5-Reflective layer, 6-Polarized light, 7-Infrared receiver, 8-Display module, 9-Static screen. Detailed Implementation

[0056] Example 1

[0057] Example 1 provides a first aspect of a posture recognition device based on a liquid crystal functional film, the structure of which includes an encoding layer group, an infrared emitting group, and an infrared receiving group; the encoding layer group includes a reflective layer and an encoding layer having two different optical anisotropy regions; the infrared emitting group includes an infrared emitter and a polarizing layer; the infrared receiving group includes an infrared receiver and a polarizing layer.

[0058] The coding layer consists of two regions with the same horizontal phase delay but different optical axis angles. The horizontal phase delay is 1 / 4 of the center output wavelength (940nm) of the infrared emitter, i.e., 235nm; the optical axis angle between them is 45°. The two regions in the coding layer form a recognizable pattern, which is uniformly distributed. The recognizable pattern has a one-to-one positional relationship; the pattern consists of Arabic numerals and letters, and the thickness of the coding layer is 2 micrometers.

[0059] The coding layer is a coding layer product sold by Shanghai Xianhuan High-Tech New Materials Co., Ltd.

[0060] The reflective layer is a superposition of a levorotatory cholesteric liquid crystal reflective layer composed of a levorotatory chiral agent and a polymerizable liquid crystal, and a dextrorotatory cholesteric liquid crystal reflective layer composed of a dextrorotatory chiral agent and a polymerizable liquid crystal.

[0061] The reflective layer is a single infrared light reflective layer with a reflectivity of 90%; the thickness of both the L-cholesterol liquid crystal reflective layer and the D-cholesterol liquid crystal reflective layer is 3 micrometers.

[0062] The reflective layer is a cholesteric liquid crystal reflective layer product sold by Shanghai Xianhuan High-Tech New Materials Co., Ltd.

[0063] With the direction of infrared light projection as the fixed direction, the structural order in the coding layer group is coding layer and reflective layer.

[0064] Infrared emitters are wearable infrared emitting devices that can be positioned and rotated.

[0065] The wearable infrared light-emitting device includes an infrared light-emitting diode made of a semiconductor material with a band gap in the infrared range; the semiconductor material is gallium arsenide; the light emission angle of the infrared light-emitting diode is 22°; the wavelength of the infrared light-emitting diode is 940nm; and the luminous power is 60mW.

[0066] The infrared emitting group polarizing layer is a 0° linear polarizer with full-spectrum absorption by stretching method. It is a 0° stretched polarizer product sold by Sumitomo Corporation of Japan, with a thickness of 30 micrometers.

[0067] An infrared receiver is an infrared CCD camera receiver; the infrared CCD camera receiver includes an indium gallium arsenide detector; the infrared CCD camera receiver also includes a light filter that filters out infrared light other than 940nm wavelength.

[0068] The infrared receiving group polarizing layer is a stretched full-spectrum absorption 0° linear polarizer, a 0° stretched polarizer product sold by Sumitomo Corporation of Japan, with a thickness of 30 micrometers.

[0069] In this embodiment, the polarization angle of the infrared emitting group's polarization layer is initially set to 0°. The coding layer is a graphic composed of two different optical axis regions, 0° and 45°. The graphic formed by the combination of letters and numbers represents the anisotropic region with the optical axis at 0°, while the background represents the anisotropic region with the optical axis at 45°. The table below shows the contrast and simulation effect of the image recognized by the infrared receiving group under different rotation angles (taking the recognition of region B3 as an example).

[0070]

[0071]

[0072]

[0073] Example 2

[0074] Based on Example 1, the number of anisotropic regions in the coding layer is increased to four, and the optical axis angles of the four anisotropic regions are set to 0°, 45°, 90°, and 135°, respectively. The table below shows the contrast and simulation effect of the image recognized by the infrared receiving group under different rotation angles (taking the recognition of region B3 as an example). With this setting, each position contains two sets of contrast information and two sets of image and text information, which is more conducive to accurately determining the pointing position and rotation angle of the infrared emitting group.

[0075]

[0076]

[0077] Example 3

[0078] This embodiment provides an application of the posture recognition device of this application. The encoding layer group of Embodiment 1 is placed on a static screen, and the infrared emitting group and infrared receiving group are placed on AR glasses. The transceiver can then obtain the location of the person's point of interest and notify the display module to retrieve a pre-stored image based on the pointing location, projecting it in front of the person's eyes to achieve augmented reality. This application can be used in advertising, art appreciation, and exploration scenarios, as shown in the appendix to the specification. Figure 3 As shown.

[0079] Through Examples 1-3 and Figures 1-2 It can be seen that the posture recognition device based on liquid crystal functional film and its application provided by the present invention have good human-computer interaction posture recognition effect, and effectively increase the recognition distance and reduce the interference effect on the main body screen. It is suitable for promotion in the field of human-computer interaction and has broad development prospects.

Claims

1. A posture recognition device based on a liquid crystal functional film, characterized in that: The structure includes a coding layer group, an infrared emission group, and at least one infrared receiving group; the coding layer group includes a reflective layer and a coding layer having at least two different optical anisotropy regions; the infrared emission group includes an infrared emitter and a polarizing layer; the infrared receiving group includes an infrared receiver and a polarizing layer. The two different optical anisotropic regions in the coding layer are optical anisotropic regions with the same horizontal phase delay and different optical axis angles; The horizontal phase delay of the two different optical anisotropic regions in the coding layer is 1 / 4 of the center output wavelength of the infrared emitter, and the optical axis angle between the anisotropic regions is ±45°. Because the encoding layer and reflective layer are transparent under visible light, the encoded information cannot be recognized by the naked eye regardless of whether it is illuminated by infrared light, nor will it interfere with the observation of information located behind the encoding layer and reflective layer. Linearly polarized light with an angle of θ emitted from the infrared emitting group passes through the encoding layer, is reflected by the reflective layer, and passes through the encoding layer again, after which its polarization angle changes to -θ and 90°-θ. The reflected light continues to pass through the polarization layer of the infrared receiving group, producing contrast and being recognized by the infrared receiver. When the infrared emitting group rotates, the contrast of the pattern received by the infrared receiver will change, and the contrast is a function of θ, so the angle of the infrared emitting group can be determined. When the infrared emitting group changes position, the pattern received by the infrared receiver will change, so the position of the infrared emitting group can be determined.

2. The attitude recognition device based on a liquid crystal functional film according to claim 1, characterized in that: The reflective layer is a cholesteric liquid crystal reflective layer.

3. The attitude recognition device based on a liquid crystal functional film according to claim 1, characterized in that: The infrared emitter is a wearable infrared emitting device that can change position and rotate angle.

4. The attitude recognition device based on a liquid crystal functional film according to claim 1, characterized in that: The infrared receiver is an infrared light receiving device located at a fixed receiving position.

5. The attitude recognition device based on a liquid crystal functional film according to claim 1, characterized in that: The polarizing layer in the infrared emitting group is at least one of a linear polarizer and a circular polarizer.

6. An application of the attitude recognition device based on a liquid crystal functional film according to any one of claims 1 to 5, characterized in that: This includes the application of this posture recognition device in posture recognition in human-computer interaction.

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