CN219302777U - Apparatus for manufacturing cholesteric liquid crystal device and near-eye display device - Google Patents

Abstract

The present utility model relates to an apparatus for manufacturing a cholesteric liquid crystal device and a near-to-eye display device, which can improve the light energy utilization rate, greatly improve the practicality of an AR device, and facilitate popularization and promotion. The near-eye display device includes: an image projector for projecting first circularly polarized light; a cholesteric liquid crystal device disposed at a projection side of the image projector, for reflecting first circularly polarized light from the image projector and transmitting second circularly polarized light, wherein a rotation direction of the second circularly polarized light is opposite to a rotation direction of the first circularly polarized light; and a see-through reflecting element provided on a reflecting side of the cholesteric liquid crystal device for reflecting the first circularly polarized light reflected via the cholesteric liquid crystal device into the second circularly polarized light to return to the cholesteric liquid crystal device to pass through the cholesteric liquid crystal device.

Description

Apparatus for manufacturing cholesteric liquid crystal device and near-eye display device

Technical Field

The utility model relates to the technical field of near-eye display, in particular to a device for manufacturing a cholesteric liquid crystal device and near-eye display equipment.

Background

In recent years, the advent of micro display chip technology has made possible miniaturized and high resolution projection displays. With the continuous development of projection display technology and market demand, wearable micro-lens systems are receiving more and more attention, especially in the fields of today's augmented reality (Augmented reality, AR) of heat and fire, near-eye display (NED), and the like.

Currently, there are a plurality of AR optical system schemes on the market, but there are still a lot of disadvantages of near-eye display devices that can be really oriented to consumers, such as low brightness, small angle of view, large size, high cost, or heavy devices. Although the reflective Birdbath optical architecture (BB optical architecture for short) based on the self-luminous display chip as the image display source has a certain advantage in terms of control cost, volume reduction and difficulty reduction, the near-to-eye display scheme based on the architecture has a problem of low light efficiency.

As shown in fig. 1, a conventional catadioptric optical system 1P is generally composed of an image display 10P, an imaging lens 20P, a concave mirror 30P (a coating spectral ratio r=60%, t=40%) and a planar half mirror 40P (a coating spectral ratio r=50%, t=50%). Thus, the image light emitted via the image display 10P passes through the imaging lens 20P: first, half (50%) of the light is reflected by the plane half mirror 40P to propagate to the concave mirror 30P, and the other half (50%) of the light is lost through the plane half mirror 40P; then, a part (60%) of the light is reflected by the concave mirror 30P to be transmitted to the plane half mirror 40P again, and another part (40%) of the light is lost through the concave mirror 30P; finally, a portion (50%) of the light passes through the half mirror 40P to reach the human eye, and another portion (50%) of the light is reflected by the half mirror 40P and lost. At the same time, ambient light can partially pass through concave mirror 30P and planar half mirror 40P to the human eye in sequence, so that the user obtains an AR experience.

However, the conventional refractive-reflective optical system 1P has a light energy utilization rate of about 15% (50%. Times.60%. Times.50%) only, which is very low, and seriously affects the practicality of the AR device.

Disclosure of Invention

An advantage of the present utility model is to provide an apparatus for manufacturing a cholesteric liquid crystal device and a near-to-eye display device that can improve light energy utilization, greatly improve the practicality of an AR device, and facilitate popularization and promotion.

Another advantage of the present utility model is to provide an apparatus for manufacturing a cholesteric liquid crystal device and a near-eye display device, wherein in one embodiment of the present utility model, the near-eye display device can use a cholesteric liquid crystal device to replace a planar half mirror in an existing BB optical architecture, so as to greatly improve the light energy utilization of an optical system.

Another advantage of the present utility model is to provide an apparatus for manufacturing a cholesteric liquid crystal device and a near-eye display device, in which in one embodiment of the present utility model, the near-eye display device can use a holographic optical element to replace a concave mirror in an existing BB optical architecture, cannot further improve light energy utilization, and can also avoid image leakage, protecting the user's privacy of use.

Another advantage of the present utility model is to provide an apparatus for manufacturing a cholesteric liquid crystal device and a near-eye display device in which expensive materials or complex structures are not required in the present utility model in order to achieve the above object. The present utility model thus successfully and efficiently provides a solution that not only provides a simple apparatus for manufacturing a cholesteric liquid crystal device and a near-eye display device, but also increases the practicality and reliability of the apparatus for manufacturing a cholesteric liquid crystal device and the near-eye display device.

To achieve at least one of the above or other advantages and objects of the utility model, the present utility model provides a near-eye display device including:

an image projector for projecting first circularly polarized light;

a cholesteric liquid crystal device disposed at a projection side of the image projector, for reflecting first circularly polarized light from the image projector and transmitting second circularly polarized light, wherein a rotation direction of the second circularly polarized light is opposite to a rotation direction of the first circularly polarized light; and

and a see-through reflecting element provided on a reflecting side of the cholesteric liquid crystal device for reflecting the first circularly polarized light reflected via the cholesteric liquid crystal device into the second circularly polarized light to return to the cholesteric liquid crystal device and to pass through the cholesteric liquid crystal device.

According to one embodiment of the present application, the image projector comprises an image source for emitting image light, an imaging lens for modulating the light, and a circularly polarizing device in an optical path between the image source and the imaging lens, the imaging lens being in an optical path between the circularly polarizing device and the cholesteric liquid crystal device.

According to one embodiment of the application, the image source is a polarization display element for emitting linearly polarized image light; the circularly polarizing element is a quarter wave plate attached to a display surface of the polarizing display element for converting linearly polarized image light from the polarizing display element into the first circularly polarized light.

According to one embodiment of the application, the image source is a non-polarizing display element for emitting natural image light; the circular polarizer comprises a quarter wave plate and a polarizing element positioned in the light path between the unpolarized display element and the quarter wave plate; the polarizing element is used for converting natural image light from the polarization display element into linear polarization image light to be transmitted to the quarter wave plate; the quarter wave plate is used for converting the linear polarized image light from the polarizing element into the first circular polarized light.

According to one embodiment of the present application, the see-through reflective element is a concave mirror or fresnel lens.

According to an embodiment of the present application, the see-through reflective element is a volume holographic optical element for reflecting all of the first circularly polarized light reflected via the cholesteric liquid crystal device into the second circularly polarized light for returning to the cholesteric liquid crystal device.

According to one embodiment of the present application, the cholesteric liquid crystal device includes a light-transmitting substrate, an alignment layer stacked on the light-transmitting substrate, and a liquid crystal layer stacked on the alignment layer; the alignment layer is positioned between the light-transmitting substrate and the liquid crystal layer, and is used for enabling liquid crystal molecules in the liquid crystal layer to be arranged according to a preset alignment so as to reflect first circularly polarized light incident along a preset angle.

According to one embodiment of the present application, the alignment layer of the cholesteric liquid crystal device is prepared using a rubbing alignment technique or a polarized light alignment technique.

According to another aspect of the present application, there is further provided an apparatus for manufacturing a cholesteric liquid crystal device, comprising:

a light source projector for projecting parallel light;

a parallel light beam splitter disposed at a projection side of the light source projector, for splitting one path of parallel light from the light source projector into reference light propagating along a reference light path and object light propagating along an object light path;

the reference light system is arranged on a reference light path of the parallel light beam splitter and used for modulating the reference light from the parallel light beam splitter so as to form reference light with a first circular polarization state to be incident on the surface of the orientation layer substrate; and

the object light system is arranged on an object light path of the parallel light beam splitter and used for modulating object light from the parallel light beam splitter to form object light with a second circular polarization state to be incident on the surface of the orientation layer substrate, wherein the rotation direction of the second circular polarization state is opposite to that of the first circular polarization state, so that the reference light and the object light perform polarization interference recording at the orientation layer substrate to form a cholesteric liquid crystal device after liquid crystal is spin-coated on the surface of the orientation layer substrate.

According to one embodiment of the present application, the object light system includes an object light phase retarder, an object light mirror, and an object light imaging lens sequentially arranged along an object light path of the parallel light beam splitter; the object light phase delay piece is used for modulating the object light from the parallel light beam splitter to form the object light with a first circular polarization state and transmitting the object light to the object light reflecting mirror; the object light reflector is used for reflecting the object light with the first circular polarization state to form the object light with the second circular polarization state to be transmitted to the object light imaging lens; the object light imaging lens is used for modulating object light with a second circular polarization state to be incident on the surface of the orientation layer substrate after forming an object light intermediate real image.

According to one embodiment of the present application, the reference light system includes a reference light phase retarder, a reference light mirror, and a reference light imaging lens sequentially arranged along a reference light path of the parallel light beam splitter; the reference light phase delay element is used for modulating the reference light from the parallel light beam splitter to form reference light with a second circular polarization state and transmitting the reference light to the reference light reflecting mirror; the reference light reflector is used for reflecting the reference light with the second circular polarization state to form the reference light with the first circular polarization state to propagate to the reference light imaging lens; the reference light imaging lens is used for modulating the reference light with a first circular polarization state to be incident on the surface of the orientation layer substrate after forming the reference light intermediate real image.

According to one embodiment of the present application, the light source projector includes a laser, a pinhole filter located in an optical path between the laser and the parallel beam splitter, and a collimator mirror located between the pinhole filter and the parallel beam splitter.

Drawings

FIG. 1 is a schematic diagram of a conventional catadioptric optical system;

FIG. 2 is a block diagram schematic of a near-eye display device according to one embodiment of the utility model;

fig. 3 shows a first example of a near-eye display device according to the above-described embodiment of the present utility model;

fig. 4 shows a second example of a near-eye display device according to the above-described embodiment of the present utility model;

fig. 5 shows a third example of a near-eye display device according to the above-described embodiment of the present utility model;

fig. 6 shows a fourth example of a near-eye display device according to the above-described embodiment of the present utility model;

fig. 7 shows an enlarged schematic view of a cholesteric liquid crystal device in a near-eye display device according to the above embodiment of the utility model;

fig. 8 is a block diagram schematic of an apparatus for manufacturing a cholesteric liquid crystal device in accordance with an embodiment of the utility model;

fig. 9 shows an example of an apparatus for manufacturing a cholesteric liquid crystal device according to the above-described embodiment of the utility model;

fig. 10 shows another example of an apparatus for manufacturing a cholesteric liquid crystal device according to the above-described embodiment of the utility model;

fig. 11 is a flow chart of a method for manufacturing a cholesteric liquid crystal device in accordance with an embodiment of the utility model.

Description of main reference numerals: 1. a near-eye display device; 10. an image projector; 11. an image source; 111. a polarization display element; 112. a non-polarizing display element; 12. an imaging lens; 13. a circularly polarizing device; 131. a quarter wave plate; 132. a polarizing element; 20. cholesteric liquid crystal devices; 200. an orientation layer substrate; 21. a light-transmitting substrate; 22. an orientation layer; 23. a liquid crystal layer; 30. a perspective reflective element; 31. a concave mirror; 32. a Fresnel lens; 33. a volume hologram optical element; 50. apparatus for manufacturing a cholesteric liquid crystal device; 51. a light source projector; 511. a laser; 5111. a line bias laser; 5112. a non-polarized laser; 512. a pinhole filter; 513. a collimator lens; 514. a line bias device; 52. a parallel beam splitter; 520. a PBS beam splitting prism; 53. a reference light system; 531. a reference light phase retarder; 532. a reference light mirror; 533. a reference light imaging lens; 54. an object light system; 541. an object light phase delay member; 542. an object light reflecting mirror; 543. an object light imaging lens.

The foregoing general description of the utility model will be described in further detail with reference to the drawings and detailed description.

Detailed Description

The following description of the embodiments of the present utility model will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present utility model, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the utility model without making any inventive effort, are intended to be within the scope of the utility model.

It is noted that when an element is referred to as being "mounted to" another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "disposed on" another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "secured to" another element, it can be directly secured to the other element or intervening elements may also be present.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this utility model belongs. The terminology used herein in the description of the utility model is for the purpose of describing particular embodiments only and is not intended to be limiting of the utility model. The term "or/and" as used herein includes any and all combinations of one or more of the associated listed items.

Considering that the existing catadioptric optical system has light energy utilization rate of about 15%, the utilization rate is extremely low, and the practicability of the AR equipment is seriously affected. The application provides a device for manufacturing a cholesteric liquid crystal device and near-to-eye display equipment, which can adopt the cholesteric liquid crystal (English: cholesteric liquid crystal, abbreviated as CLC) device to replace a plane half mirror in the existing BB optical architecture, so as to greatly improve the light energy utilization rate of an optical system.

Specifically, referring to fig. 2, an embodiment of the present utility model provides a near-eye display device 1, which may include an image projector 10 for projecting first circularly polarized light, a cholesteric liquid crystal device 20 for reflecting the first circularly polarized light and transmitting second circularly polarized light, and a see-through reflecting element 30 for reflecting the first circularly polarized light into the second circularly polarized light. The rotation direction of the first circularly polarized light is opposite to the rotation direction of the second circularly polarized light. The cholesteric liquid crystal device 20 is disposed at a projection side of the image projector 10 for reflecting the first circularly polarized light projected via the image projector 10; the see-through reflective element 30 is disposed on the reflective side of the cholesteric liquid crystal device 20 for reflecting the first circularly polarized light reflected via the cholesteric liquid crystal device 20 into the second circularly polarized light to return to the cholesteric liquid crystal device 20 and further to penetrate the cholesteric liquid crystal device 20 to enter human eye for imaging. At the same time, ambient light will sequentially pass through the see-through reflective element 30 and the cholesteric liquid crystal device 20 to enter the human eye for imaging, so that the user can view the virtual image and the real environment at the same time to obtain an AR experience.

It is understood that the first circularly polarized light and the second circularly polarized light mentioned in the present application are implemented as image light having a first circular polarization state and a second circular polarization state, respectively, and the directions of rotation of the first circular polarization state and the second circular polarization state are opposite; for example, as shown in fig. 3 to 6, when the first circularly polarized light is implemented as Left circularly polarized light (LCP for short), the second circularly polarized light is implemented as Right circularly polarized light (RCP for short) (Right-handed circularly polarized for short); in contrast, only the cholesteric liquid crystal device 20 needs to be correspondingly aligned, which is not described in detail in the present application.

It is noted that, since the cholesteric liquid crystal device mentioned in the present application has strong polarization selectivity, it is capable of totally reflecting at an angle satisfying the bragg law for circularly polarized light of a certain rotation direction (i.e., first circularly polarized light) and totally transmitting for circularly polarized light of another rotation direction (i.e., second circularly polarized light); therefore, the first circularly polarized light projected by the image projector 10 is reflected by the cholesteric liquid crystal device 20 (approximately 100%) to be transmitted to the perspective reflective element 30, and then is reflected by the perspective reflective element 30 to be the second circularly polarized light, and then is transmitted through the cholesteric liquid crystal device 20 (approximately 100%) to enter the human eye to be imaged, so that the image light is only lost at the perspective reflective element 30, the light energy utilization rate of the optical system is ensured to be greatly improved, the practicality of the near-to-eye display device (such as AR glasses) is greatly improved, and the popularization and the promotion are facilitated.

More specifically, as shown in fig. 2 to 6, the image projector 10 may include an image source 11 for emitting image light, an imaging lens 12 for modulating the light, and a circular polarization device 13 between the image source 11 and the imaging lens 12, the imaging lens 12 being located in an optical path between the circular polarization device 13 and the cholesteric liquid crystal device 20. The circularly polarizing means 13 is for modulating the image light from the image source 11 into the first circularly polarized light to propagate to the imaging lens 12; the imaging lens 12 is used to modulate the first circularly polarized light from the circularly polarizing device 13 to propagate to the cholesteric liquid crystal device 20.

Alternatively, the imaging lens 12 may be implemented to consist of one or more lenses, but is not limited to. Notably, the imaging lens 12 referred to herein may include one or more of a geometric lens, a fresnel lens, and a holographic lens; in addition, the lens surface shape of the imaging lens 12 may be, but not limited to, one or more of a standard spherical surface, an aspherical surface, a free-form surface, and a diffraction surface, which will not be described in detail herein.

Illustratively, as shown in fig. 3, in a first example of the present application, the image source 11 may be implemented as a polarization display element 111 for emitting linearly polarized image light. For example, the polarized display element 111 may be implemented as, but is not limited to, an LCD display element.

Correspondingly, in the above-described first example of the present application, as shown in fig. 3, the circularly polarizing device 13 is implemented as a quarter wave plate 131 for converting linearly polarized image light from the polarizing display element 111 into the first circularly polarized light to propagate to the imaging lens 12. Optionally, the quarter wave plate 131 may be attached to the display surface of the polarization display element 111 to form an image source with a specific integrated structure, so as to facilitate assembly of the optical system.

It is noted that the optical properties of the cholesteric liquid crystal device referred to herein are determined by the alignment layer, and based on the particular alignment layer design and exposure, the cholesteric liquid crystal device can have a lens-like optical power while having polarization selectivity. In other words, the cholesteric liquid crystal device 20 of the present application, while acting as a planar optical element, may have a lens-like optical power to cooperate with the imaging lens 12 for modulated imaging, helping to reduce the number of lenses of the imaging lens 12, facilitating a reduction in the overall volume and weight of the device.

Further, as shown in fig. 3, the cholesteric liquid crystal device 20 and the see-through reflecting element 30 are arranged along the viewing axis L of the near-eye display apparatus 1, and an angle between the surface of the cholesteric liquid crystal device 20 and the viewing axis L is between 50 ° and 70 °, so that a human eye views a virtual image and a real environment along the viewing axis L.

Alternatively, in the above-described first example of the present application, as shown in fig. 3, the perspective reflecting element 30 may be implemented as a concave reflecting mirror 31, wherein the concave reflecting mirror 31 has a predetermined spectral ratio structure for reflecting a portion of light and transmitting another portion of light. For example, the spectral ratio of the coating film of the concave mirror 31 is implemented as reflectance r=60% and transmittance t=40%; that is, the concave mirror 31 can reflect 60% of the first circularly polarized light reflected by the cholesteric liquid crystal device 20 into the second circularly polarized light to propagate back to the cholesteric liquid crystal device 20, and at this time, the light energy utilization rate of the near-to-eye display device 1 is increased to 60%, which is much greater than 15% of the existing catadioptric optical system.

It is worth mentioning that fig. 4 shows a second example of a near-eye display device according to the above-described embodiments of the present application. The near-eye display device 1 according to the second example of the present application is different from the above-described first example according to the present application in that: the image source 11 may be implemented as a non-polarizing display element 112 for emitting natural image light. For example, the non-polarizing display element 112 may be implemented as, but is not limited to, one of an OLED display element, a Micro LED display element, and an LCOS display element.

Correspondingly, in the above second example of the present application, as shown in fig. 4, the circularly polarizing device 13 includes a quarter-wave plate 131 and a polarizing element 132 located in the optical path between the unpolarized display element 112 and the quarter-wave plate 131; the polarizer 132 converts natural image light from the polarization display 111 into linearly polarized light to propagate to the quarter wave plate 131; the quarter wave plate 131 is used to convert the linearly polarized light from the polarizing element 132 into the first circularly polarized light to propagate to the imaging lens 12.

Alternatively, the polarizing element 132 may be implemented as, but not limited to, a polarizing film, wherein the polarizing film may be attached to the surface of the quarter wave plate 131 or the display surface of the non-polarizing display element 112, so long as the natural image light can be converted into the first circularly polarized light, which is not described herein. It can be understood that, although the light efficiency loss of the polarizer 132 is 50% when converting the natural image light into the first circularly polarized light, the light efficiency of the near-eye display device 1 can still reach 30% (i.e. 60% by 50%) and still be greater than 15% of the conventional refractive-reflective optical system.

It is noted that although in the above-described first example and the above-described second example of the present application, the near-eye display device 1 employs the concave mirror 31 as the perspective reflecting element 30 to allow a part of ambient light to pass therethrough while reflecting a part of image light to realize an augmented reality experience of virtual-real fusion; but the concave mirror 31 has a large sagittal height, which results in a large overall volume and a heavy overall weight of the near-eye display device. In order to reduce the overall volume and weight of the device, fig. 5 shows a third example of a near-eye display device according to the above-described embodiments of the present application. The near-eye display device 1 according to the third example of the present application is different from the above-described first example according to the present application in that: the see-through reflective element 30 may be implemented as a fresnel lens 32 to take advantage of the thin nature of the fresnel lens in combination with the coating to address the greater bulk weight.

However, the saw-tooth structure of the fresnel lens 32 generally affects the perspective effect of the real scene, and the fresnel lens 32 still uses a semi-transparent and semi-reflective film to implement the perspective reflection function, which has the problem of image leakage, as in the concave mirror 31 in the first and second examples, that part of the image light is viewed by others through the concave mirror 31 and the fresnel lens 32, severely affecting the privacy of the user.

In order to solve the privacy disclosure problem, fig. 6 shows a fourth example of a near-eye display device according to the above-described embodiment of the present application. The near-eye display device 1 according to the fourth example of the present application is different from the above-described third example of the present application in that: the see-through reflective element 30 may be implemented as a volume holographic optical element 33 to address the problem of image leakage using the angle-selective features of the volume Holographic Optical Element (HOE).

It should be noted that the volume hologram optical element 33 mentioned in the present application is a planar optical element which is manufactured on a photosensitive film material recording medium such as photopolymer, silver halide emulsion, dichromated gelatin, etc. by using optical interference hologram technology and has a phase modulation function similar to that of a glass lens, wherein the theoretical diffraction efficiency of the volume hologram optical element 33 when the bragg condition is satisfied can reach 100%, and the volume hologram optical element 33 has no modulation effect on the polarization state of light, i.e. the first circularly polarized light reflected by the cholesteric liquid crystal device 20 forms second circularly polarized light after being reflected by the volume hologram optical element 33 to be reflected back to the cholesteric liquid crystal device 20; at this time, the second circularly polarized light will not be subjected to the phase modulation of the cholesteric liquid crystal device 20, so as to be completely transmitted into human eyes to form amplified virtual images, and no additional loss of light efficiency exists in the whole process. In other words, the volume hologram optical element 33 of the present application can reflect almost all the first circularly polarized light reflected by the cholesteric liquid crystal device 20 into the second circularly polarized light to propagate back to the cholesteric liquid crystal device 20 to prevent leakage of image light, and at this time, the light energy utilization rate of the near-to-eye display device 1 can approach 100%, which is far greater than 15% of the existing refractive-reflective optical system. Meanwhile, the volume hologram optical element 33 of the present application is a planar optical element, which is also light and thin, and is more beneficial to the design of a light and thin near-to-eye display system.

It will be appreciated that in this example of the present application, since the volume hologram optical element 33 and the cholesteric liquid crystal device 20 each have extremely high transmittance, ambient light can directly enter the human eye through the volume hologram optical element 33 and the cholesteric liquid crystal device 20 without causing obstruction to the real scene and loss of light efficiency. In addition, the specific structure and manufacturing method of the volume hologram optical element 33 of the present application may refer to chinese patent application No. 2022109072391, which is filed by the applicant of the present application, for a device and method for manufacturing a hologram optical element and a near-eye display device, and the present application will not be repeated herein.

It is noted that the alignment technique of liquid crystal can realize the orderly arrangement of liquid crystal molecules relative to the surface of the substrate according to the design requirement, which is a necessary condition for the normal operation of the liquid crystal optical element. At present, the common liquid crystal alignment technology comprises two types of rubbing alignment and photo alignment, wherein the rubbing alignment technology is to rub flannelette on an alignment film to one direction so as to form an alignment layer, and liquid crystal molecules at the alignment layer are arranged in parallel according to the rubbing direction; in the photo-alignment technique, an alignment layer is formed by changing an alignment material by photo-crosslinking or photo-degradation by using a method such as polarization interference or mask exposure.

Alternatively, in the above-described embodiment of the present application, as shown in fig. 7, the cholesteric liquid crystal device 20 may include a light-transmitting substrate 21, an alignment layer 22 stacked on the light-transmitting substrate 21, and a liquid crystal layer 23 stacked on the alignment layer 22; the alignment layer 22 is located between the light-transmitting substrate 21 and the liquid crystal layer 23, and is configured to align liquid crystal molecules in the liquid crystal layer 23 according to a predetermined orientation to reflect first circularly polarized light incident along a predetermined angle. It is understood that the alignment layer 22 of the present application may be prepared using rubbing alignment techniques, polarized light alignment techniques, laser direct writing techniques, spatial light modulator techniques, and mask exposure techniques.

It should be noted that, since the near-eye display device 1 of the present application can greatly improve the light energy utilization rate, mainly because the cholesteric liquid crystal device 20 specially made in the present application can totally reflect the first circularly polarized light to the perspective reflective element 30 and allow the second circularly polarized light from the perspective reflective element 30 to totally transmit; therefore, how to manufacture the cholesteric liquid crystal device 20 satisfying the above conditions is another key point of the present application.

In particular, fig. 8-10 illustrate an apparatus 50 for manufacturing a cholesteric liquid crystal device according to one embodiment of the present application for producing the above-described cholesteric liquid crystal device 20 using a polarized light alignment technique. The apparatus 50 for manufacturing a cholesteric liquid crystal device may include a light source projector 51 for projecting parallel light, a parallel light beam splitter 52 provided at a projection side of the light source projector 51, a reference light system 53, and an object light system 54. The parallel beam splitter 52 is configured to split one path of parallel light from the light source projector 51 into reference light propagating along a reference light path and object light propagating along an object light path. The reference light system 53 is disposed on the reference light path of the parallel beam splitter 52, and is used for modulating the reference light from the parallel beam splitter 52 to form the reference light with the first circular polarization state to be incident on the surface of the alignment layer substrate 200; the object light system 54 is disposed on the object light path of the parallel beam splitter 52, and is configured to modulate the object light from the parallel beam splitter 52 to form the object light with a second circular polarization state incident on the surface of the alignment layer substrate 200, wherein the second circular polarization state has a rotation direction opposite to that of the first circular polarization state, so that the reference light and the object light perform polarization interference recording on the surface of the alignment layer substrate 200, and the cholesteric liquid crystal device 20 is formed after the liquid crystal is spin-coated on the surface of the alignment layer substrate 200. It is understood that the object light incident on the surface of the alignment layer substrate 200 mentioned in the present application has the same angle as the incident light beam in the near-eye display device 1; in other words, the spatial angular distribution of the object light incident on the surface of the alignment layer substrate 200 and the spatial angular distribution of the image light reflected to the cholesteric liquid crystal device 20 by the perspective reflective element 30 in the near-eye display device 1 are consistent, so as to ensure that the cholesteric liquid crystal device 20 meets the requirement of the near-eye display device 1.

More specifically, as shown in fig. 9 and 10, the light source projector 51 may include a laser 511, a pinhole filter 512 located in an optical path between the laser 511 and the parallel beam splitter 52, and a collimator lens 513 located in an optical path between the pinhole filter 512 and the parallel beam splitter 52. Thus, the laser beam emitted by the laser 511 is filtered by the pinhole filter 512, collimated by the collimator 513, and then split into the reference beam and the object beam perpendicular to each other by the parallel beam splitter 52.

Alternatively, as shown in fig. 9 and 10, the object light system 54 may include an object light phase retarder 541, an object light mirror 542, and an object light imaging lens 543 sequentially arranged along an object light path of the parallel light beam splitter 52. The object light phase retarder 541 is configured to modulate the object light from the parallel beam splitter 52 to form an object light with a first circular polarization state and transmit the object light to the object light reflector 542; the object light reflector 542 is configured to reflect the object light having the first circular polarization state to form the object light having the second circular polarization state for propagating to the object light imaging lens 543; the object-light imaging lens 543 is configured to modulate the object light having the second circular polarization state to be incident on the surface of the alignment layer substrate 200 after forming the object-light intermediate real image.

Optionally, as shown in fig. 9 and 10, the parallel beam splitter 52 may be implemented as a PBS beam splitter prism 520, for reflecting the second polarized light in the parallel light to form a reference light and transmitting the first polarized light in the parallel light to form an object light, so as to improve the light energy utilization of the object light and simultaneously achieve the manufacturing requirement of the cholesteric liquid crystal device 20, which is not repeated herein.

According to the above-described embodiment of the present application, as shown in fig. 9 and 10, the reference light system 53 may include a reference light phase retarder 531, a reference light mirror 532, and a reference light imaging lens 533 sequentially arranged along the reference light path of the parallel light beam splitter 52. The reference light phase retarder 531 is configured to modulate the reference light from the parallel beam splitter 52 to form reference light having a second circular polarization state and propagate the reference light to the reference light mirror 532; the reference light reflector 532 is configured to reflect the reference light having the second circular polarization state to form the object light having the first circular polarization state for propagation to the reference light imaging lens 533; the reference light imaging lens 533 is used for modulating the reference light having the first circular polarization state to be incident on the surface of the alignment layer substrate 200 after forming the reference light intermediate real image.

Illustratively, the object light phase retarder 541 and the reference light phase retarder 531 may each be implemented as a 1/4 wave plate for modulating linearly polarized light into circularly polarized light.

Notably, in one example of the present application, as shown in fig. 9, the laser 511 of the light source projector 51 may be implemented as a linear polarization laser 5111 for directly emitting laser light having a linear polarization state; at this time, the reference light and the object light split by the parallel beam splitter 52 are both linearly polarized light to be modulated into desired circularly polarized light by the corresponding 1/4 wave plate. Of course, in another example of the present application, as shown in fig. 10, the laser 511 may also be implemented as an unpolarized laser 5112 for directly emitting unpolarized laser light; at this time, the light source projector 51 may further include a linear polarization device 514 located in an optical path between the unpolarized laser 5112 and the pinhole filter 512 for modulating the unpolarized laser light emitted via the unpolarized laser 5112 into laser light having a linear polarization state such that it can still be modulated into desired circularly polarized light by the corresponding 1/4 wave plate.

In addition, the alignment layer base 200 may include a light-transmitting substrate 21 and an alignment film (not shown in the drawings) provided to the light-transmitting substrate 21; the surface of the alignment layer substrate 200 is provided with the alignment film such that both the reference light modulated by the reference light system 53 and the object light modulated by the object light system 54 are directly incident on the alignment film. Thus, the reference light having the first circular polarization state and the object light having the second circular polarization state interfere at the alignment film to be recorded by the alignment film exposure, and the cholesteric liquid crystal device 20 is formed after spin-coating the liquid crystal. It is understood that the material of the alignment film may be, but is not limited to, an alignment material that is implemented to be capable of undergoing a change of photocrosslinking, photodegradation, or the like; the material of the light-transmitting substrate 21 may be, but is not limited to, implemented as transparent glass.

It should be noted that fig. 11 illustrates a manufacturing method for a cholesteric liquid crystal device according to an embodiment of the present application, which may include the steps of:

s100: splitting a beam of parallel light into a path of reference light and a path of object light;

s200: modulating the reference light into reference light with a first circular polarization state to be incident on the surface of the orientation layer substrate;

s200: modulating the object light into object light with a second circular polarization state to be incident on the surface of the orientation layer substrate, wherein the rotation direction of the second circular polarization state is opposite to that of the first circular polarization state;

s400: recording information of polarization interference between the reference light with the first circular polarization state and the object light with the second circular polarization state through the orientation layer substrate; and

s500: and spin-coating liquid crystal on the surface of the alignment layer substrate to form a cholesteric liquid crystal device.

It is noted that the order between step S200 and step S200 in the method for manufacturing a hologram optical element of the present application is performed in parallel regardless of the order.

The technical features of the above embodiments may be arbitrarily combined, and all possible combinations of the technical features in the above embodiments are not described for brevity of description, however, as long as there is no contradiction between the combinations of the technical features, they should be considered as the scope of the description.

The foregoing examples illustrate only a few embodiments of the utility model, which are described in detail and are not to be construed as limiting the scope of the utility model. It should be noted that it will be apparent to those skilled in the art that several variations and modifications can be made without departing from the spirit of the utility model, which are all within the scope of the utility model. Accordingly, the scope of protection of the present utility model is to be determined by the appended claims.

Claims (12)

1. A near-eye display device, comprising:

an image projector for projecting first circularly polarized light;

a cholesteric liquid crystal device disposed at a projection side of the image projector, for reflecting first circularly polarized light from the image projector and transmitting second circularly polarized light, wherein a rotation direction of the second circularly polarized light is opposite to a rotation direction of the first circularly polarized light; and

and a see-through reflecting element provided on a reflecting side of the cholesteric liquid crystal device for reflecting the first circularly polarized light reflected via the cholesteric liquid crystal device into the second circularly polarized light to return to the cholesteric liquid crystal device and to pass through the cholesteric liquid crystal device.

2. A near-eye display device as claimed in claim 1, characterized in that the image projector comprises an image source for emitting image light, an imaging lens for modulating the light, and a circularly polarizing means in the optical path between the image source and the imaging lens, the imaging lens being in the optical path between the circularly polarizing means and the cholesteric liquid crystal means.

3. The near-eye display device of claim 2, wherein the image source is a polarized display element for emitting linearly polarized image light; the circularly polarizing element is a quarter wave plate attached to a display surface of the polarizing display element for converting linearly polarized image light from the polarizing display element into the first circularly polarized light.

4. A near-eye display device as claimed in claim 2, characterized in that the image source is a non-polarizing display element for emitting natural image light; the circular polarizer comprises a quarter wave plate and a polarizing element positioned in the light path between the unpolarized display element and the quarter wave plate; the polarizing element is used for converting natural image light from the polarization display element into linear polarization image light to be transmitted to the quarter wave plate; the quarter wave plate is used for converting the linear polarized image light from the polarizing element into the first circular polarized light.

5. A near-eye display device as claimed in any one of claims 1 to 4, characterized in that the see-through reflecting element is a concave mirror or a fresnel lens.

6. A near-eye display device as claimed in any one of claims 1 to 4, characterized in that the see-through reflecting element is a volume holographic optical element for totally reflecting the first circularly polarized light reflected via the cholesteric liquid crystal device into the second circularly polarized light for return to the cholesteric liquid crystal device.

7. The near-eye display device of any one of claims 1 to 4, wherein the cholesteric liquid crystal device comprises a light-transmitting substrate, an alignment layer stacked on the light-transmitting substrate, and a liquid crystal layer stacked on the alignment layer; the alignment layer is positioned between the light-transmitting substrate and the liquid crystal layer, and is used for enabling liquid crystal molecules in the liquid crystal layer to be arranged according to a preset alignment so as to reflect first circularly polarized light incident along a preset angle.

8. A near-eye display device as claimed in claim 7, characterized in that the alignment layer of the cholesteric liquid crystal device is prepared using a rubbing alignment technique or a polarized light alignment technique.

9. An apparatus for manufacturing a cholesteric liquid crystal device, comprising:

a light source projector for projecting parallel light;

a parallel light beam splitter disposed at a projection side of the light source projector, for splitting one path of parallel light from the light source projector into reference light propagating along a reference light path and object light propagating along an object light path;

the reference light system is arranged on a reference light path of the parallel light beam splitter and used for modulating the reference light from the parallel light beam splitter so as to form reference light with a first circular polarization state to be incident on the surface of the orientation layer substrate; and

the object light system is arranged on an object light path of the parallel light beam splitter and used for modulating object light from the parallel light beam splitter to form object light with a second circular polarization state to be incident on the surface of the orientation layer substrate, wherein the rotation direction of the second circular polarization state is opposite to that of the first circular polarization state, so that the reference light and the object light perform polarization interference recording at the orientation layer substrate to form a cholesteric liquid crystal device after liquid crystal is spin-coated on the surface of the orientation layer substrate.

10. The apparatus for manufacturing a cholesteric liquid crystal device according to claim 9, wherein the object light system includes an object light phase retarder, an object light mirror, and an object light imaging lens arranged in this order along an object light path of the parallel beam splitter; the object light phase delay piece is used for modulating the object light from the parallel light beam splitter to form the object light with a first circular polarization state and transmitting the object light to the object light reflecting mirror; the object light reflector is used for reflecting the object light with the first circular polarization state to form the object light with the second circular polarization state to be transmitted to the object light imaging lens; the object light imaging lens is used for modulating object light with a second circular polarization state to be incident on the surface of the orientation layer substrate after forming an object light intermediate real image.

11. The apparatus for manufacturing a cholesteric liquid crystal device according to claim 9, wherein the reference light system includes a reference light phase retarder, a reference light mirror, and a reference light imaging lens sequentially arranged along a reference light path of the parallel light beam splitter; the reference light phase delay element is used for modulating the reference light from the parallel light beam splitter to form reference light with a second circular polarization state and transmitting the reference light to the reference light reflecting mirror; the reference light reflector is used for reflecting the reference light with the second circular polarization state to form the reference light with the first circular polarization state to propagate to the reference light imaging lens; the reference light imaging lens is used for modulating the reference light with a first circular polarization state to be incident on the surface of the orientation layer substrate after forming the reference light intermediate real image.

12. An apparatus for manufacturing a cholesteric liquid crystal device according to any one of claims 9 to 11, wherein the light source projector comprises a laser, a pinhole filter in an optical path between the laser and the parallel beam splitter, and a collimator lens between the pinhole filter and the parallel beam splitter.

Images