CN213715607U - Display optical system for reducing ghost and head-mounted display device - Google Patents

Abstract

The utility model discloses a reduce display optical system and head mounted display device of ghost, wherein, reduce display optical system of ghost, including display screen, polarization beam splitting component, first polarization conversion component, partial transmission part reflection element, second polarization conversion component and the polarization piece that sets gradually; the display optical system further includes a lens disposed on a side of the partially transmissive partially reflective element facing the display screen; the lens is attached to the first polarization conversion element, and/or the lens is attached to the polarization beam splitting element; the first polarization conversion element and the polarization light splitting element are arranged at intervals, the surface of the first polarization conversion element exposed in the air is provided with a substrate, and the substrate is provided with an antireflection film. The utility model discloses technical scheme can reduce the interface that different components in the folding light path and expose the ghost that produces fresnel reflection and cause in the air to improve display optical system's image quality, and have lightweight characteristics.

Description

Display optical system for reducing ghost and head-mounted display device

Technical Field

The utility model relates to an optical display technical field, in particular to reduce display optical system and wear display device of ghost.

Background

In near eye display (ned) or head mounted display (hmd) optical systems, optical films (optical films) are becoming more and more widely used because of their functionality and cost performance, such as polarizers and compensators of polarization control elements, playing an important role in folded optical paths (pancakes). However, exposure of these elements to air can cause fresnel reflection (a phenomenon in which a portion of light is reflected when the light is incident on an interface between two media having different refractive indices), which in turn causes ghost images that affect image quality.

There are three main approaches to solve this problem. The first is to coat an AR (Anti-Reflection) layer on the surface of the polarization control element or to compound an optical Film with AR function, but these materials can only have low reflectivity (such as < 0.7%, DNP LR Film) around 589nm, and cannot keep good uniform performance in the whole visible light range. The second approach, in which a Quarter Wave Plate (QWP) is combined with a Polarizing Beam Splitter (PBS) and then attached to a substrate, reduces one optical reflection surface, but the reflection from the remaining optical surface is still significant and the corresponding ghosting plays a major role in imaging. The third is to combine the QWP and the PBS, and attach the QWP to the rear surface of the lens, or attach the QWP to the two lenses, so as to reduce the corresponding reflection, but in order to meet the requirements of diopter and image quality, the solution has disadvantages of thicker lens, increased weight, and the like, and thus the application of the QWP in the product is limited.

SUMMERY OF THE UTILITY MODEL

The utility model aims at providing a reduce display optical system of ghost, aim at reducing the ghost that different components's interface exposes in the air and produces fresnel reflection and cause in folding light path, improve display optical system's image quality to have lightweight characteristics.

In order to achieve the above object, the present invention provides a display optical system for reducing ghost, which includes a display screen, a polarization splitting element, a first polarization conversion element, a partial transmission partial reflection element, a second polarization conversion element and a polarization element, which are sequentially disposed; the display optical system further includes a lens disposed on a side of the partially transmissive partially reflective element facing the display screen; the lens is attached to the first polarization conversion element, and/or the lens is attached to the polarization beam splitting element; the first polarization conversion element and the polarization light splitting element are arranged at intervals, the surface of the first polarization conversion element exposed in the air is provided with a substrate, and the substrate is provided with an antireflection film.

Optionally, the lens is disposed between the partially transmissive partially reflective element and the first polarization conversion element, the lens is simultaneously disposed in contact with the partially transmissive partially reflective element and the first polarization conversion element, an air space exists between the first polarization conversion element and the polarization splitting element, and a substrate and an antireflection film are disposed on a surface of the first polarization conversion element facing the polarization splitting element and a surface of the polarization splitting element facing the first polarization conversion element.

Alternatively, the curvature of the surface of the substrate facing the first polarization conversion element and the curvature of the surface of the substrate facing the polarization splitting element are the same.

Alternatively, the curvature of the surface of the substrate facing the first polarization conversion element is the same as the curvature of the surface of the lens facing the first polarization conversion element.

Optionally, a surface of the substrate facing the first polarization conversion element is planar.

Optionally, the substrate has a dispersion characteristic opposite to that of the lens.

Optionally, an optical glue is filled between the lens and the first polarization conversion element.

Optionally, an optical adhesive is filled between the first polarization conversion element and the substrate.

Optionally, the optical cement is made of an index matching material.

In order to achieve the above object, the utility model discloses still provide a reduce head mounted display device of ghost, include: a head-mounted body; and the display optical system for reducing the ghost is arranged in the head-mounted main body.

The utility model discloses technical scheme adopts display screen, polarization beam splitting component, first polarization converting element, partial transmission partial reflection component, second polarization converting element and polarization piece to set up according to the preface, and lens set up in one side of partial transmission partial reflection component towards the display screen, can realize the folding of polarization light path. The first polarization conversion element is attached to the lens, and/or the lens is attached to the polarization beam splitting element, so that the lens is directly contacted with one or two adjacent elements, namely, no air isolation exists between the lens and the adjacent elements attached to the lens, and therefore ghost images caused by Fresnel reflection of corresponding interfaces can be reduced; simultaneously, be provided with the substrate and be located the antireflection coating on the substrate through the surface that exposes in the air at first polarization conversion element, the substrate can make surface reflectivity show the reduction to make the antireflection coating have higher reliability, the ghost phenomenon that the antireflection coating can further reduce fei nieer reflection and produce, consequently, the utility model discloses can reduce the ghost phenomenon because of fei nieer reflection produces in the folding light path by a wide margin, thereby improve display optical system's image quality. Moreover, because the distance between the lens and the polarization beam splitting element can be adjusted according to actual requirements to meet the requirements of diopter and image quality of optical design, adverse factors such as thicker lens and increased weight can be avoided, so that the display optical system for reducing ghost has the characteristic of light weight, can meet the requirements of a head-mounted display device on weight, and is convenient to popularize and apply in products.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the structures shown in the drawings without creative efforts.

FIG. 1 is a schematic diagram of a basic folded optical path (the direction indicated by the arrow in the figure is the direction of the main image optical path);

fig. 2 is a schematic structural view of an embodiment of a display optical system for reducing ghosting according to the present invention (the direction indicated by the arrow in the figure is the direction of the remaining ghost optical path);

FIG. 3 is a schematic structural diagram of another embodiment of a display optical system for reducing ghosting according to the present invention (the direction indicated by the arrow in the figure is the direction of the remaining ghost optical path);

FIG. 4 is a schematic view of the display optical system for reducing ghosting in FIG. 3 in which a lens is attached to a first polarization conversion element;

FIG. 5 is a schematic view of a lens, a first polarization conversion element and a substrate in the display optical system for reducing ghost image in FIG. 3;

fig. 6 is a schematic structural diagram of a lens, a first polarization conversion element and a substrate in another embodiment of the display optical system for reducing ghosting according to the present invention.

The reference numbers illustrate:

the objects, features and advantages of the present invention will be further described with reference to the accompanying drawings.

Detailed Description

The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative efforts belong to the protection scope of the present invention.

It should be noted that, if directional indications (such as upper, lower, left, right, front and rear … …) are involved in the embodiment of the present invention, the directional indications are only used to explain the relative position relationship between the components, the motion situation, etc. in a specific posture (as shown in the drawings), and if the specific posture is changed, the directional indications are changed accordingly.

In addition, if there is a description relating to "first", "second", etc. in the embodiments of the present invention, the description of "first", "second", etc. is for descriptive purposes only and is not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In addition, the technical solutions in the embodiments may be combined with each other, but it must be based on the realization of those skilled in the art, and when the technical solutions are contradictory or cannot be realized, the combination of the technical solutions should not be considered to exist, and is not within the protection scope of the present invention.

The utility model provides a reduce display optical system 100 of ghost.

As an embodiment of the present invention, please refer to fig. 2 to 5, the display optical system for reducing ghost includes a display screen 10, a polarization beam splitter 60, a first polarization conversion element 30, a partially transmissive partially reflective element 90, a second polarization conversion element 50, and a polarizer 20, which are sequentially disposed; the display optical system further includes a lens 40 disposed on a side of the partially transmissive partially reflective element 90 facing the display screen; the lens 40 is attached to the first polarization conversion element 30, and/or the lens 40 is attached to the polarization beam splitter element 60; the first polarization conversion element 30 and the polarization beam splitting element 60 are arranged at an interval, a substrate 70 is arranged on the surface of the first polarization conversion element 30 exposed to the air, and an antireflection film 71 is arranged on the substrate 70.

Referring to fig. 1, fig. 1 is a schematic diagram illustrating a basic structure of a folded optical path (the direction indicated by an arrow in the figure is the direction of a main image optical path). The basic folded optical path structure includes a display screen 10, a polarization splitting element 60, a first polarization conversion element 30, a lens 40, a partially transmissive partially reflective element 90, a second polarization conversion element 50, and a polarizer 20, which are sequentially disposed.

The polarization beam splitter 60 (PBS) may be a bragg-type reflective polarizer or a wire grid-type reflective polarizer. The first polarization conversion element 30 is specifically a Quarter Wave Plate (QWP) capable of imparting a retardation of a quarter wavelength between the fast and slow axis components to the incident polarized light, and the azimuth angle of the optical axis of the quarter wave plate to the transmission axis of the polarization beam splitter 60 is usually 40 ° to 50 °, and further 44 ° to 46 °. The lens 40 has a certain refractive power and may be a plano-convex lens, a biconvex lens or a meniscus lens with a positive focal length, and for better aberration control, the lens 40 is preferably biconvex, i.e. the surface of the lens 40 facing the first polarization conversion element 30 and the surface of the lens 40 facing the second polarization conversion element 50 are both convex. The partially transmissive and partially reflective element 90 (e.g., a light splitting film, typically a transflective film) may be disposed separately from the lens 40, or may be attached to a surface of the lens 40 facing away from the screen, preferably attached to a surface of the lens facing away from the screen, and has a transmittance of 30% to 70%, further 40% to 60%. The second polarization conversion element 50 is specifically a Quarter Wave Plate (QWP), and the material of the second polarization conversion element 50 may be the same as or different from that of the first polarization conversion element 30, and is preferably the same as that of the first polarization conversion element 30. The optical axis direction of the second polarization conversion element 50 is generally two, one is parallel to the first polarization conversion element 30, and the other is perpendicular to the first polarization conversion element 30. When the first scheme is adopted, the transmission axis of the polarizing member 20 is parallel to the polarization splitting element 60, and when the second scheme is adopted, the transmission axis of the polarizing member 20 is perpendicular to the polarization splitting element 60. The polarizer 20 is preferably an absorptive polarizer such as a PVA (polyvinyl alcohol) polarizer commonly used in the display industry. With this configuration, the polarizer 20 can absorb the polarized light of the straight light path and transmit the polarized light of the folded light path, thereby achieving the effect of correctly displaying the folded main image of the light path.

In the above folded light path structure, the specific directions of the light rays are as follows: the light of the picture element on the display screen 10 is polarized into linear polarization by the polarization light splitting element 60, and is changed into circular polarization after passing through the first polarization conversion element 30, and is reflected when reaching the partial transmission partial reflection element 90, and passes through the first polarization conversion element 30 for the second time, because of the half-wave loss caused by reflection, the chirality of the circular polarization is reversed, when the reflected light reaches the polarization light splitting element 60, the polarization direction is parallel to the reflection axis of the polarization light splitting element 60 and is reflected, when the light passes through the first polarization element 30 for the third time, the chirality is opposite to that of the first pass, the light continues to pass through the second polarization conversion element 50 and is changed into linear polarization again, at the moment, the polarization direction is parallel to the transmission axis of the polarization piece 20, and therefore, the main image can be formed by.

On the basis of the basic folded light path, the display optical system for reducing ghost image of the present invention is specifically described, in the embodiment of the present invention, the lens 40 is disposed on one side of the partially transmissive partially reflective element 90 facing the display screen; the lens 40 is attached to the first polarization conversion element 30, and/or the lens 40 is attached to the polarization beam splitter element 60; the first polarization conversion element 30 and the polarization beam splitting element 60 are arranged at an interval, a substrate 70 is arranged on the surface of the first polarization conversion element 30 exposed to the air, and an antireflection film 71 is arranged on the substrate 70.

Specifically, the above structure includes at least four cases:

first, the lens 40 is disposed between the partially transmissive partially reflective element 90 and the first polarization conversion element 30, the lens 40 is attached to the second polarization conversion element 50, and the surface of the first polarization conversion element 30 facing the polarization splitting element 60 is provided with the substrate 70 and the antireflection film 71.

Secondly, the lens 40 is disposed between the first polarization conversion element 30 and the polarization beam splitter 60, the lens 40 is attached to the first polarization conversion element 30, the lens 40 is disposed at a distance from the polarization beam splitter 60, and the surface of the first polarization conversion element 30 facing the first polarization conversion element 30 is provided with the substrate 70 and the antireflection film 71.

Thirdly, the lens 40 is disposed between the first polarization conversion element 30 and the polarization beam splitter 60, the lens 40 is simultaneously attached to the first polarization conversion element 30 and the polarization beam splitter 60, and the surface of the first polarization conversion element 30 facing the first polarization conversion element 30 is provided with a substrate 70 and an antireflection film 71.

Fourthly, the lens 40 is arranged on one side of the polarization beam splitting element 60 departing from the first polarization conversion element 30, and the lens 40 and the polarization beam splitting element 60 are attached; when the first polarization conversion element 30 is attached to the partially transmissive and partially reflective element 90, the substrate 70 and the antireflection film 71 are disposed on the surface of the first polarization conversion element 30 facing the polarization splitting element 60; when the first polarization conversion element 30 and the polarization splitting element 60 are attached to each other, the substrate 70 and the antireflection film 71 are disposed on the surface of the first polarization conversion element 30 facing the first polarization conversion element 30.

The first polarization conversion element 30 and the polarization splitting element 60 may be spaced apart from each other by the lens 40 or may be spaced apart from each other by air. When the lens 40 is attached to the first polarization conversion element 30 or the lens 40 is attached to the polarization splitting element 60, an air space is provided between the first polarization conversion element 30 and the polarization splitting element 60. When the lens 40 is attached to the first polarization conversion element 30 and the polarization splitting element 60 at the same time, the first polarization conversion element 30 and the polarization splitting element 60 are spaced apart from each other by the lens 40.

It is understood that the lens 40 is disposed adjacent to the first polarization conversion element 30, or the lens 40 is disposed adjacent to the polarization splitting element 60, or the lens 40 is disposed adjacent to both the first polarization conversion element 30 and the polarization splitting element 60, that is, the lens 40 is in direct contact with one or both of the adjacent elements, and there is no air separation between the lens 40 and the adjacent element adjacent thereto, so that the ghost image caused by the fresnel reflection at the corresponding interface can be reduced. Meanwhile, a substrate 70 and an antireflection film 71 disposed on the substrate 70 are disposed on the surface of the first polarization conversion element 30 exposed to air, and the antireflection film 71, also called an antireflection film, has the main functions of reducing the reflected light from the optical surface and increasing the light transmittance, so as to further reduce the ghost phenomenon caused by fresnel reflection. In summary, the lens 40 is attached to the first polarization conversion element 30, and/or the polarization beam splitter 60 is attached to the substrate 70 and the antireflection film 71 are disposed on the surface of the first polarization conversion element 30 exposed to air, so that the ghost phenomenon caused by fresnel reflection can be greatly reduced, and the image quality of the display optical system can be improved.

In practice, if an anti-reflection (AR) film is directly plated on the surface of the first polarization conversion element 30 facing the polarization beam splitter 60, the surface reflection is usually between 0.5% and 1%, and the dispersion performance is poor, so that an obvious color cast phenomenon is easily generated, and high reliability cannot be obtained. In this embodiment, the substrate 70 is additionally disposed on the surface of the first polarization conversion element 30 facing the polarization beam splitting element 60, and then an anti-reflection (AR) film is plated on the surface of the substrate 70 facing the polarization beam splitting element 60, so that the surface reflectivity can be significantly reduced, for example, 0.3%, and the reliability is higher. Therefore, compared with directly plating the antireflection film 71 on the surface of the first polarization conversion element 30, in the embodiment, the ghost can be further reduced by 50% to 70%, and the effect of reducing the ghost is more obvious.

It should be noted that the present invention does not limit the distance between any two elements of the display screen 10, the polarization splitting element 60, the first polarization conversion element 30, the partially transmissive partially reflective element 90, the lens 40, and the polarizer 20, and can be set according to actual requirements. For example, the pitch of the lens 40 and the polarization splitting element 60 may be determined according to the optical design of the main image. Therefore, the technical scheme can meet the requirements of diopter adjustment and imaging quality of optical design, avoids the adverse factors of thicker lens 40, increased weight and the like, and is suitable for popularization and application in products. Therefore, the display optical system 100 for reducing ghosting also has a characteristic of light weight, and can satisfy the requirement of a Head Mounted Display (HMD) device for weight.

In an embodiment of the present invention, referring to fig. 3 to 5, the lens 40 is disposed between the partial transmission partial reflection element 90 and the first polarization conversion element 30, the lens 40 is disposed in contact with the partial transmission partial reflection element 90 and the first polarization conversion element 30, an air gap exists between the first polarization conversion element 30 and the polarization splitting element 60, and the surface of the first polarization conversion element 30 facing the polarization splitting element 60 and the surface of the polarization splitting element 60 facing the first polarization conversion element 30 are both provided with the substrate 70 and the antireflection film 71.

Wherein the remaining ghost beam path formed by the interface reflection at the front surface of the substrate 70 (i.e., toward the polarization splitting element 60) is shown in FIG. 2 at RR relative to the principal image_pcos²δ, where R is the reflectance of the partially transmissive partially reflective element 90, Rp is the reflectance of the polarization splitting element 60 in the transmission axis direction, and cos δ is the light leakage caused by the retardation of the first polarization conversion element 30 deviating from the quarter optical path.

In this embodiment, the lens 40 is in direct contact with the partially transmissive partially reflective element 90, and the lens 40 is in direct contact with the first polarization conversion element 30, so that there is no air isolation between the lens 40 and the partially transmissive partially reflective element 90, and between the lens 40 and the first polarization conversion element 30, and therefore, the ghost image caused by the fresnel reflection at the corresponding interface can be reduced. Meanwhile, the surface of the first polarization conversion element 30 exposed in the air (i.e., the surface facing the polarization splitting element 60) and the surface of the polarization splitting element 60 exposed in the air (i.e., the surface facing the first polarization conversion element 30) are both provided with the substrate 70 and the antireflection film 71, the substrate 70 can significantly reduce the surface reflectivity, and the antireflection film 71 has higher reliability, and the antireflection film 71 can further reduce the ghost phenomenon generated by fresnel reflection, thereby improving the image quality of the display optical system. In addition, the distance between the lens 40 and the polarization beam splitter 60 can be determined according to the optical design of the main image to meet the diopter adjustment and the requirements of the optical design for the image quality.

Further, referring to fig. 4 to 5, the curvature of the surface of the substrate 70 facing the first polarization conversion element 30 is the same as the curvature of the surface of the substrate 70 facing the polarization splitting element 60.

In this embodiment, the substrate 70 has no focal power, that is, the curvatures of the front and back surfaces of the substrate 70 are the same, so that the direction of light in the original optical path structure is not affected, thereby ensuring the normal operation of the original optical path structure and ensuring the optical performance of the original optical path structure.

Further, referring to fig. 4 to 5, the curvature of the surface of the substrate 70 facing the first polarization conversion element 30 is the same as the curvature of the surface of the lens 40 facing the first polarization conversion element 30.

Specifically, the first polarization conversion element 30 (for example, a quarter-wave plate) may be formed by crystal, polymer stretching, liquid crystal coating, or the like, and preferably has a thin film form such as polymer stretching and liquid crystal coating, so as to be easily attached to curved surfaces of lenses having different curvature radii. When the first polarization conversion element 30 is attached to the surface of the lens 40, the first polarization conversion element 30 can be adapted to the shape of the lens 40. Moreover, in the present embodiment, the curvature of the front and back surfaces of the substrate 70 is also the same as the curvature of the back surface of the lens 40 (i.e. the surface facing the first polarization conversion element 30), so that the substrate 70 can be well glued together with the first polarization conversion element 30 on the back surface of the lens 40, and the light direction in the original light path structure is not affected, thereby ensuring the imaging quality.

In another embodiment of the present invention, referring to fig. 6, the surface of the substrate 70 facing the first polarization conversion element 30 is a plane.

In the case where the front surface of the lens 40 (i.e., the surface facing the first polarization conversion element 30) is nearly planar, for example, R >500mm, the substrate 70 may be considered to be a planar element, i.e., the front and back surfaces of the substrate 70 (i.e., the surfaces facing the first polarization conversion element 30 and the polarization splitting element 60) are both planar, and when the diameter reaches 40mm, the edge gap is less than 0.5mm, so as to facilitate filling and curing of the optical cement, the optical cement is preferably an index matching material, and the filled combined lens is equivalent to a lens formed by an index matching material and is cemented with the lens 40. Thus, the effect of reducing the ghost image can be realized, the process difficulty and the manufacturing cost can be reduced by the structure, but the influence brought by the cemented lens needs to be considered in the imaging design.

Optionally, the substrate 70 has a dispersion characteristic opposite to that of the lens 40.

By selecting proper materials, the chromatic aberration of the system can be additionally corrected on the premise of not influencing the prior optical performance. Specifically, the substrate 70, which is flat or without diopter (i.e., the curvatures of the front and rear surfaces are the same), has a positive positional chromatic aberration, which is related to the refractive index, the thickness and the abbe number, and the convex lens 40 has a negative positional chromatic aberration, so that an appropriate material and thickness can be selected based on a corresponding chromatic aberration calculation formula, such as a primary seidel aberration and a high-order chromatic aberration, so that the display optical system has a more ideal chromatic aberration expression. In the present embodiment, chromatic aberration of the lens 40 is compensated by the substrate 70 having the opposite dispersion characteristic to that of the lens 40, and chromatic aberration can be effectively eliminated.

Further, an optical paste 80 is filled between the lens 40 and the first polarization conversion element 30.

In this embodiment, the lens 40 and the second polarization conversion element are bonded together by an optical adhesive 80. The optical adhesive 80 (adhesive for bonding optical parts) is a special adhesive for bonding transparent optical parts, and is required to be colorless and transparent, have a light transmittance of 90% or more, have good bonding strength, be curable at room temperature or at intermediate temperature, and have the characteristics of small curing shrinkage and the like. Adhesives such as silicone, acrylic, unsaturated polyester, polyurethane, epoxy and the like can be used to bond the optical parts. The optical adhesive 80 is a polymer having optical properties similar to those of optical parts and excellent adhesive properties. The optical adhesive 80 may be selectively coated on the rear surface of the lens 40 (i.e., the surface facing the first polarization conversion element 30), or may be selectively coated on the front surface of the first polarization conversion element 30 (i.e., the surface facing the lens 40), preferably on the first polarization conversion element 30, because the first polarization conversion element 30 (e.g., the quarter-wave plate) is soft as a whole, the first polarization conversion element 30 may be in a planar state before the first polarization conversion element 30 is attached to the lens 40, and after the optical adhesive 80 is coated on the front surface of the first polarization conversion element 30, the first polarization conversion element 30 is attached to the rear surface of the lens 40 and adapted to the convex shape of the lens 40, so that better uniformity and flatness can be achieved. Meanwhile, a bubble removing machine is required to perform vacuum bubble removing operation to prevent the bubble residue in the gap between the first polarization conversion element 30 and the lens 40 from scattering the imaging light when the first polarization conversion element and the lens 40 are glued.

Further, an optical paste 80 is filled between the first polarization conversion element 30 and the substrate 70.

In this embodiment, the first polarization conversion element 30 and the substrate 70 are also bonded together by the optical adhesive 80. The optical adhesive 80 may be selectively coated on the front surface of the substrate 70 (i.e., the surface facing the first polarization conversion element 30), or may be selectively coated on the rear surface of the first polarization conversion element 30 (i.e., the surface facing the polarization splitting element 60), preferably on the rear surface of the first polarization conversion element 30, because the first polarization conversion element 30 (e.g., the quarter-wave plate) is soft as a whole, the first polarization conversion element 30 may be in a planar state before the first polarization conversion element 30 is attached to the lens 40, after the optical adhesive 80 is coated on the front and rear surfaces of the first polarization conversion element 30, the first polarization conversion element 30 is attached to the rear surface of the lens 40 and adapted to the convex shape of the lens 40, and finally, the substrate 70 is attached to the rear surface of the first polarization conversion element 30, which can achieve better uniformity and flatness. Meanwhile, a bubble removing machine is required to perform vacuum bubble removing operation to prevent the bubble residue in the gap between the first polarization conversion element 30 and the substrate 70 from scattering the imaging light when the first polarization conversion element and the substrate are bonded.

Specifically, the optical cement 80 employs an index matching material.

Matching here means that the difference in refractive index between the materials at the two sides of the interface is reduced, thereby minimizing the loss of reflected light. Index matching is an important optical means, and aims to make the refractive index of a contact substance conform to a certain rule so as to reduce the reflection of light or increase the transmission of light. Interface reflection inside the optical system can be reduced by selecting the refractive index matching material, so that ghost is reduced, and imaging quality is improved.

Alternatively, the substrate 70 may be made of glass, resin, or an optical film.

In this embodiment, the material of the substrate 70 is preferably glass. As can be seen from the coating process, a better coating effect can be generally achieved at a high temperature, because the substrate is pretreated, the substrate is firstly activated, the chemical bond between the substrate and the coating material is increased, the bonding force between the coating and the substrate is improved, and the absorption of the substrate impurity gas and the high refractive index coating material is reduced, in addition, some low-refraction materials such as magnesium fluoride (MgF2) used as the anti-reflection film 71 are only suitable for high-temperature deposition, and glass generally has a better high-temperature resistance characteristic, so that compared with resin and optical films, the substrate 70 is made of glass, and can achieve lower interface reflection and better reliability of the coating material.

The utility model provides a reduce display device that wears of ghost still, this reduce display device that wears of ghost includes that the main part is worn to the head and the display optical system 100 that reduces the ghost, and the above-mentioned embodiment is referred to the concrete structure of the display optical system 100 that should reduce the ghost, because this reduce display device that wears of ghost has adopted all technical scheme of above-mentioned all embodiments, consequently has all beneficial effects that the technical scheme of above-mentioned embodiment brought at least, does not give unnecessary detail here one by one again.

Wherein, wear the main part and can include the frame that is suitable for wearing at user's head, be used for adjusting the elasticity adjusting device of frame constraint degree to and be connected with the display optical system in order to carry out the control system etc. that controls display screen 10, wear the specific structure and the setting of main part and can adopt prior art, no longer describe here.

The above only be the preferred embodiment of the utility model discloses a not consequently restriction the utility model discloses a patent range, all are in the utility model discloses a conceive, utilize the equivalent structure transform of what the content was done in the description and the attached drawing, or direct/indirect application all is included in other relevant technical field the utility model discloses a patent protection within range.

Claims (11)

1. A display optical system for reducing ghost is characterized by comprising a display screen, a polarization beam splitting element, a first polarization conversion element, a partial transmission partial reflection element, a second polarization conversion element and a polarization piece which are sequentially arranged;

the display optical system further includes a lens disposed on a side of the partially transmissive partially reflective element facing the display screen; the lens is attached to the first polarization conversion element, and/or the lens is attached to the polarization splitting element; the first polarization conversion element and the polarization light splitting element are arranged at intervals, a substrate is arranged on the surface, exposed to the air, of the first polarization conversion element, and an antireflection film is arranged on the substrate.

2. The display optical system according to claim 1, wherein the lens is disposed between the partially transmissive partially reflective element and the first polarization conversion element, the lens is disposed in contact with the partially transmissive partially reflective element and the first polarization conversion element, an air gap is present between the first polarization conversion element and the polarization splitting element, and the substrate and the antireflection film are disposed on a surface of the first polarization conversion element facing the polarization splitting element and a surface of the polarization splitting element facing the first polarization conversion element.

3. The ghost-reducing display optical system according to claim 1, wherein a curvature of a surface of the substrate facing the first polarization conversion element is the same as a curvature of a surface of the substrate facing the polarization beam splitting element.

4. The ghost-reducing display optical system according to claim 3, wherein a curvature of a surface of the substrate facing the first polarization conversion element is the same as a curvature of a surface of the lens facing the first polarization conversion element.

5. The ghost-reducing display optical system according to claim 3, wherein a surface of the substrate facing the first polarization conversion element is a flat surface.

6. The ghost-reducing display optical system of claim 3, wherein the substrate has a dispersion characteristic opposite to that of the lens.

7. The ghost-reducing display optical system according to any one of claims 2 to 6, wherein an optical glue is filled between the lens and the first polarization conversion element.

8. The ghost-reducing display optical system according to any one of claims 2 to 6, wherein an optical paste is filled between the first polarization conversion element and the substrate.

9. The ghost-reducing display optical system according to claim 7, wherein the optical paste is made of an index matching material.

10. The ghost-reducing display optical system according to claim 8, wherein the optical paste is made of an index matching material.

11. A head-mounted display device with reduced ghosting, comprising:

a head-mounted body; and

the ghost-reducing display optical system according to any one of claims 1 to 10, the ghost-reducing display optical system being provided within the head-mounted body.

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