阅读说明：本技术 菲涅尔透镜、菲涅尔透镜组件及虚拟现实显示装置 (Fresnel lens, Fresnel lens assembly and virtual reality display device ) 是由 黄海涛 韩娜 董瑞君 白家荣 武玉龙 栗可 王晨如 崔钊 井丽娜 马占山 陈丽莉 于 2021-09-06 设计创作，主要内容包括：本公开提供一种菲涅尔透镜、菲涅尔透镜组件及虚拟现实显示装置,属于显示技术领域,其可解决现有的菲涅尔透镜中容易形成杂散光,对正常光线造成干扰,降低显示效果的问题。本公开的菲涅尔透镜的至少一面具有多个锯齿状结构,锯齿状结构包括：入光面、侧面、及连接入光面和侧面的圆角；菲涅尔透镜还包括：杂散光消除结构；杂散光消除结构被配置为将经过侧面和圆角的光线进行遮挡或吸收。(The utility model provides a fresnel lens, fresnel lens subassembly and virtual reality display device belongs to and shows technical field, and it can solve and form stray light easily among the current fresnel lens, causes the interference to normal light, reduces display effect's problem. At least one side of the fresnel lens of the present disclosure has a plurality of sawtooth-shaped structures, and the sawtooth-shaped structures include: the light source comprises a light incident surface, a side surface and a fillet connecting the light incident surface and the side surface; the fresnel lens further includes: a stray light eliminating structure; the stray light elimination structure is configured to block or absorb light passing through the side surface and the rounded corner.)

1. A fresnel lens, wherein at least one side of the fresnel lens has a plurality of sawtooth-shaped structures, the sawtooth-shaped structures comprising: the light source comprises a light incident surface, a side surface and a round angle connecting the light incident surface and the side surface; the fresnel lens further includes: a stray light eliminating structure;

the stray light elimination structure is configured to block or absorb light passing through the side surface and the round corner.

2. The fresnel lens according to claim 1, wherein the sawtooth-shaped structure further comprises: the light emergent surface is opposite to the light incident surface;

the stray light eliminating structure is positioned on one side of the light emitting surface and is arranged on a light path of light passing through the side surface and the round angle.

3. The fresnel lens according to claim 2, wherein the stray light removal structure is embedded in the light exit surface.

4. The fresnel lens according to claim 1, wherein the stray light elimination structure comprises: a first wedge and a second wedge;

the first wedge covers the side of the sawtooth-like structure;

the second wedge covers the rounded corner of the sawtooth-like structure.

5. The Fresnel lens according to claim 4, wherein the first wedge portion and the second wedge portion are of an integrally formed construction.

6. The Fresnel lens according to claim 4, wherein the stray light eliminating structure further comprises: a transparent substrate;

the first wedge-shaped part and the second wedge-shaped part are both positioned on one side, close to the light incident surface, of the transparent substrate.

7. The fresnel lens according to claim 1, wherein the stray light elimination structure comprises: and a black matrix.

8. A fresnel lens assembly, characterized in that it comprises a plurality of fresnel lenses according to any one of claims 1 to 7;

centers of the Fresnel lenses are positioned on the same straight line.

9. The fresnel lens assembly of claim 8, wherein an air gap is provided between some adjacent ones of the plurality of fresnel lenses.

10. A virtual reality display apparatus, comprising a fresnel lens assembly according to any one of claims 8 to 9.

Technical Field

The utility model belongs to the technical field of show, concretely relates to fresnel lens, fresnel lens subassembly and virtual reality display device.

Background

In the Virtual Reality (VR) display technology, a display image displayed on a display panel is generally imaged to a position 25 mm to 50 mm in front of human eyes or closer by using a lens, and different images are respectively seen by left and right eyes of a person, so that a stereoscopic impression is generated after brain processing, and a user has an immersive feeling.

The prior virtual reality display device can adopt a straight-through type aspheric lens component and a return type aspheric lens component to realize the convergence of light rays, wherein the straight-through type aspheric lens component has high luminous efficiency which can reach more than 80 percent, but has thicker thickness which is generally more than 35 mm; the thickness of the folding lens component is thin and can reach below 25 mm, but the light efficiency is low and is generally less than 25%. In order to achieve the effects of high light efficiency and thin thickness, a fresnel lens assembly is often adopted, however, in the fresnel lens, an invalid surface exists, and light rays easily generate stray light after passing through the invalid surface, so that the display effect is affected, and the use experience of a user is reduced.

Disclosure of Invention

The present disclosure is directed to at least one of the technical problems in the prior art, and provides a fresnel lens, a fresnel lens assembly and a virtual reality display apparatus.

In a first aspect, an embodiment of the present disclosure provides a fresnel lens, where at least one surface of the fresnel lens has a plurality of sawtooth structures, where the sawtooth structures include: the light source comprises a light incident surface, a side surface and a round angle connecting the light incident surface and the side surface; the fresnel lens further includes: a stray light eliminating structure;

the stray light elimination structure is configured to block or absorb light passing through the side surface and the round corner.

Optionally, the saw-toothed structure further comprises: the light emergent surface is opposite to the light incident surface;

the stray light eliminating structure is positioned on one side of the light emitting surface and is arranged on a light path of light passing through the side surface and the round angle.

Optionally, the stray light eliminating structure is embedded in the light exit surface.

Optionally, the stray light eliminating structure includes: a first wedge and a second wedge;

the first wedge covers the side of the sawtooth-like structure;

the second wedge covers the rounded corner of the sawtooth-like structure.

Optionally, the first wedge portion and the second wedge portion are of an integrally formed structure.

Optionally, the stray light eliminating structure further includes: a transparent substrate;

the first wedge-shaped part and the second wedge-shaped part are both positioned on one side, close to the light incident surface, of the transparent substrate.

Optionally, the stray light eliminating structure includes: and a black matrix.

In a second aspect, embodiments of the present disclosure provide a fresnel lens assembly comprising a plurality of fresnel lenses as provided above;

centers of the Fresnel lenses are positioned on the same straight line.

Optionally, an air gap is provided between some adjacent fresnel lenses in the plurality of fresnel lenses.

In a third aspect, embodiments of the present disclosure provide a virtual reality display apparatus, which includes the fresnel lens assembly provided as described above.

Drawings

FIG. 1 is a schematic diagram of an exemplary Fresnel lens configuration;

FIG. 2 is a schematic cross-sectional view of the Fresnel lens shown in FIG. 1 along the direction A-A';

FIG. 3 is a light path diagram of the Fresnel lens shown in FIG. 2;

fig. 4 is a schematic structural diagram of a fresnel lens provided in an embodiment of the present disclosure;

fig. 5 is a schematic structural diagram of another fresnel lens provided in the embodiment of the present disclosure;

fig. 6 is a schematic structural diagram of another fresnel lens provided in the embodiment of the present disclosure;

fig. 7 is a schematic structural diagram of a fresnel lens assembly provided in an embodiment of the present disclosure;

FIG. 8 is a graph of a modulation transfer function of the Fresnel lens assembly shown in FIG. 7;

fig. 9 is a schematic structural diagram of another fresnel lens assembly provided in the embodiments of the present disclosure;

fig. 10 is a graph of the modulation transfer function of the fresnel lens assembly shown in fig. 9.

Detailed Description

For a better understanding of the technical aspects of the present disclosure, reference is made to the following detailed description taken in conjunction with the accompanying drawings.

Unless otherwise defined, technical or scientific terms used herein shall have the ordinary meaning as understood by one of ordinary skill in the art to which this disclosure belongs. The use of "first," "second," and similar terms in this disclosure is not intended to indicate any order, quantity, or importance, but rather is used to distinguish one element from another. Also, the use of the terms "a," "an," or "the" and similar referents do not denote a limitation of quantity, but rather denote the presence of at least one. The word "comprising" or "comprises", and the like, means that the element or item listed before the word covers the element or item listed after the word and its equivalents, but does not exclude other elements or items. The terms "connected" or "coupled" and the like are not restricted to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "upper", "lower", "left", "right", and the like are used merely to indicate relative positional relationships, and when the absolute position of the object being described is changed, the relative positional relationships may also be changed accordingly.

Fig. 1 is a schematic structural diagram of an exemplary fresnel lens, and as shown in fig. 1, the fresnel lens is formed by removing excess optical material in a common lens by using an etching process based on the common lens, only preserving curvature of a part of a surface thereof, and forming a plurality of concentric rings from small to large by etching, wherein the plurality of concentric rings can form the fresnel lens, and the total weight and thickness of the lens can be reduced. Fig. 2 is a schematic cross-sectional structure view of the fresnel lens shown in fig. 1 along a direction a-a', and as shown in fig. 2, at least one surface of the fresnel lens has a plurality of sawtooth structures 101, and in the embodiment of the present disclosure, one surface of the fresnel lens has a plurality of sawtooth structures 101, and the other surface of the fresnel lens may be a spherical surface or an aspheric surface. The zigzag structure includes: the light source includes a light incident surface 1011, a side surface 1012, a rounded corner 1013 connecting the light incident surface 1011 and the side surface 1012, and a light emitting surface 1014 disposed opposite the light incident surface 1011. In practical applications, the width of each sawtooth-shaped structure 101 may be equal to form an equally spaced fresnel lens structure, or the height of each sawtooth-shaped structure 101 may be equal to form an equally toothed fresnel lens structure. The size of the sawtooth-shaped structure 101 in the fresnel lens can be set reasonably according to actual needs, and is not limited herein.

Fig. 3 is an optical path diagram of the fresnel lens shown in fig. 2, and as shown in fig. 3, when light rays enter from the light incident surface 1011, the light rays can be refracted once inside the saw-toothed structure 101 after passing through the light incident surface 1011, and exit from the light exiting surface 1014, so as to achieve the light converging effect. When a light ray enters from the position of the rounded corner 1013, the light ray can be refracted once inside the zigzag structure 101 after passing through the rounded corner 1013, and the light ray can exit from the side 1012 and enter the light incident surface 1011 of the adjacent zigzag structure 101 again, and is refracted once again, and finally exits from the light exiting surface 1014 of the adjacent zigzag structure 101.

It can be seen that the light incident from the light incident surface 1011 is refracted only once inside the sawtooth-shaped structure 101, but the light incident from the position of the rounded corner 1013 is refracted twice inside the sawtooth-shaped structure 101. In practical applications, most of light rays are incident from the light incident surface 1011 of the sawtooth-shaped structure 101, the light incident surface 1011 of the sawtooth-shaped structure 101 can be defined as an effective surface, and the positions of the side surface 1012 and the rounded corner 1013 of the sawtooth-shaped structure 101 can be defined as an ineffective surface, because the light rays incident from the effective surface and the ineffective surface have different refraction times in the sawtooth-shaped structure 101, the light rays incident from the ineffective surface of the sawtooth-shaped structure 101 have different light paths, and are easy to form stray light, which affects the display effect, thereby reducing the user experience.

In order to solve at least one of the above technical problems, embodiments of the present disclosure provide a fresnel lens, a fresnel lens assembly, and a virtual reality display apparatus, and the fresnel lens, the fresnel lens assembly, and the virtual reality display apparatus provided in embodiments of the present disclosure will be described in further detail with reference to the accompanying drawings and specific embodiments.

Fig. 4 is a schematic structural diagram of a fresnel lens provided in an embodiment of the present disclosure, and as shown in fig. 4, at least one surface of the fresnel lens has a plurality of sawtooth structures 101, in the embodiment of the present disclosure, a surface of the fresnel lens has a plurality of sawtooth structures 101 as an example, and another surface of the fresnel lens may be a spherical surface or an aspheric surface. The serration structure 101 includes: a light incident surface 1011, a side surface 1012, and a rounded corner 1013 connecting the light incident surface 1011 and the side surface 1012; the fresnel lens further includes: a stray light eliminating structure 102; the stray light elimination structure 102 is configured to block or absorb light passing through the side 1012 and the rounded corner 1013.

For example, the serrated structure 101 may be made of a material with high transparency, such as glass and acrylic, so that light can be effectively transmitted in the serrated structure 101 in a polar manner, blocking of the serrated structure 101 to light is reduced, and the light efficiency of the fresnel lens is improved. The stray light elimination structure 102 may be made of black or other dark light-shielding materials to effectively shield or absorb light, so as to prevent stray light from being formed, and further prevent the stray light from interfering with normal light.

In the fresnel lens provided by the embodiment of the present disclosure, after light passes through the light incident surface 1011, the light can be refracted once inside the saw-toothed structure 101, so as to realize the light convergence effect; after the light passes through the side surface 1012 and the round corner 1013, the light may be refracted twice inside the saw-toothed structure 101, so as to form stray light having a different optical path from the light passing through the light incident surface 1011. The stray light eliminating structure 102 can shield or absorb light passing through the side surface 1012 and the round corner 1013, that is, the stray light passing through the invalid surface is shielded or absorbed, so that the stray light is prevented from being emitted from the fresnel lens to enter the field of view of a user, and therefore the interference of the stray light on normal light can be avoided, the display effect can be improved, and the user experience can be improved.

It can be understood that the fresnel lens provided in the embodiment of the present disclosure may also have a plurality of sawtooth structures 101 on both sides, and a corresponding stray light elimination structure 102 is provided, and the implementation principle thereof is the same as that of the fresnel lens described above, and is not described herein again. In practical applications, the type of the fresnel lens can be reasonably selected according to practical needs, and is not limited herein. The dimensions such as the curvature of the light incident surface 101 and the angle of the rounded corner 1013 of the sawtooth structure 101 may be set as required, and are not limited here.

In some embodiments, as shown in fig. 4, the serration structure 101 further comprises: a light emitting surface 1014 disposed opposite to the light incident surface 1011; the stray light removing structure 102 is located on one side of the light emitting surface 1014, and is disposed on the light path of the light passing through the side surface 1012 and the rounded corner 1013.

In practical application, light passes through the side 1012 and the fillet 1013 of the sawtooth-shaped structure 101 to form stray light, the stray light elimination structure 102 can be arranged on one side of the light emitting surface 1014 and arranged on the light path of the stray light, so that the stray light elimination structure 102 can shield or absorb the stray light, the stray light is prevented from being emitted from the light emitting surface 1014 of the sawtooth-shaped structure 101 to enter the visual field of a user, the interference of the stray light on normal light can be avoided, the display effect can be improved, and the user experience can be improved.

In some embodiments, fig. 5 is a schematic structural diagram of another fresnel lens provided in the embodiments of the present disclosure, and as shown in fig. 5, the stray light eliminating structure 102 is embedded in the light emitting surface 1014.

The fresnel lens shown in fig. 5 is different from the fresnel lens shown in fig. 4 in that, in the process of manufacturing the fresnel lens shown in fig. 4, the stray light eliminating structure 102 can be directly formed on one side of the light emitting surface 1014 of the sawtooth-shaped structure 101, the manufacturing process is simple, and the manufacturing cost can be saved; in the fresnel lens shown in fig. 5, the stray light eliminating structure 102 may be embedded in the light emitting surface 1014 of the sawtooth-shaped structure 101, and in the manufacturing process, corresponding grooves may be formed on the light emitting surface 1014 of the sawtooth-shaped structure 101 at first, and then the stray light eliminating structure 102 is formed in each groove, so that the stray light eliminating structure 102 is embedded in the groove, and thus the stray light eliminating structure 102 and the light emitting surface 1014 of the sawtooth-shaped structure 101 are on the same plane, which may prevent the stray light eliminating structure 102 from increasing the overall thickness of the fresnel lens, thereby facilitating the thinning of the fresnel lens.

In some embodiments, fig. 6 is a schematic structural diagram of another fresnel lens provided in the embodiments of the present disclosure, and as shown in fig. 6, the stray light eliminating structure 102 includes: a first wedge 1021 and a second wedge 1022; the first wedge 1021 covers the side 1012 of the sawtooth-like structure 101; the second wedge 1022 covers the rounded corner 1013 of the sawtooth-like structure 101.

In the embodiment of the present disclosure, the first wedge 1021 may cover the side 1012 of the sawtooth-shaped structure 101, and the second wedge 1022 may cover the position of the circular bead 1013 of the sawtooth-shaped structure 101, wherein the first wedge 1021 and the second wedge 1022 may block or absorb light, the first wedge 1021 may block light from entering the side 1012 of the sawtooth-shaped structure 101, and the second wedge 1022 may block light from entering the position of the circular bead 1013 of the sawtooth-shaped structure 101, so that light may be prevented from propagating inside the sawtooth-shaped structure 101 and being refracted multiple times to form stray light, thereby avoiding interference of the stray light on normal light, so as to improve a display effect, and further improving user experience.

In some embodiments, the first wedge 1021 and the second wedge 1022 are a unitary structure.

In practical applications, the first wedge part 1021 and the second wedge part 1022 may be made of the same material and manufactured by the same process, so that the number of process steps may be reduced, the process difficulty may be reduced, and the manufacturing cost may be saved. On the other hand, the first wedge part 1021 and the second wedge part 1022 are integrally formed, so that the overall strength of the stray light elimination structure 102 can be effectively increased, and a gap is prevented from being generated between the first wedge part 1021 and the second wedge part 1022, and stray light is prevented from being formed due to light leakage. Also, the curvature of the surface of the first wedge 1021 is the same as the curvature of the side 1012 of the sawtooth-like structure 102 to ensure that the first wedge 1021 fits snugly against the side 1012. Similarly, the curvature of the surface of the second wedge 1022 is the same as the curvature of the rounded corner 1023 of the saw-tooth structure 102 to ensure that the second wedge 1022 fits snugly with the rounded corner.

In some embodiments, as shown in fig. 6, the stray light elimination structure 102 further includes: a transparent substrate 1023; the first wedge 1021 and the second wedge 1022 are both located on a side of the transparent substrate 1023 near the light incident surface 1011.

The transparent substrate 1023 can be made of a material with high rigidity and transparency, such as glass and acrylic, and the transparent substrate 1023 can improve the carrying capacity of the first wedge 1021 and the second wedge 1022 on the transparent substrate 1023 while ensuring light transmission. In the preparation process, the first wedge part 1021 and the second wedge part 1022 are formed on the transparent substrate 1023, and then the transparent substrate 1023 with the first wedge part 1021 and the second wedge part 1022 is attached to a plurality of sawtooth-shaped structures 101 in a box-to-box mode, so that the first wedge part 1021 can cover the side 1012 of the sawtooth-shaped structures 101, and the second wedge part 1022 can cover the positions of the round corners 1013 of the sawtooth-shaped structures 101, and thus, light can be prevented from being transmitted inside the sawtooth-shaped structures 101 and refracted for multiple times to form stray light, and the interference of the stray light on normal light can be avoided, so that the display effect is improved, and the use experience of a user can be improved. On the other hand, the first wedge part 1021 and the second wedge part 1022 are firstly formed on the transparent substrate 1023, and then the transparent substrate 1023 formed with the first wedge part 1021 and the second wedge part 1022 is attached to a plurality of sawtooth-shaped structures 101, so that damage to the sawtooth-shaped structures 101 in the etching process for forming the first wedge part 1021 and the second wedge part 1022 can be prevented, and the product yield of the fresnel lens can be improved to save the manufacturing cost.

In some embodiments, the stray light elimination structure 102 includes: and a black matrix.

The stray light elimination structure 102 may be formed by using a black matrix commonly used in the display field, so that it is not necessary to develop a new material for shielding or absorbing light, thereby reducing the manufacturing cost.

The embodiment of the present disclosure further provides a fresnel lens assembly, which includes a plurality of non-fresnel lenses provided in any of the above embodiments; the centers of the Fresnel lenses are located on the same straight line.

The light converging effect of the fresnel lens provided by the embodiment of the present disclosure will be further described in detail with reference to specific examples.

Example one: fig. 7 is a schematic structural diagram of a fresnel lens assembly provided in an embodiment of the present disclosure, and as shown in fig. 7, three fresnel lenses are provided in the fresnel lens assembly, and a plurality of sawtooth structures are provided on both sides of each fresnel lens. Fig. 8 is a graph of the modulation transfer function of the fresnel lens assembly shown in fig. 7. as shown in fig. 7 and 8, the three-piece fresnel lens assembly can achieve the effects of a focal length of 21 mm, an overall length of the assembly of 20 mm, a field angle of 90 °, and an Eye box of 8 mm by 8 mm.

Example two: fig. 9 is a schematic structural diagram of another fresnel lens assembly provided in the embodiment of the present disclosure, and as shown in fig. 9, five fresnel lenses are provided in the fresnel lens assembly, and a plurality of sawtooth structures are provided on both sides of each fresnel lens. Fig. 10 is a graph of the modulation transfer function of the fresnel lens assembly shown in fig. 9. as shown in fig. 9 and 10, the three-piece fresnel lens assembly can achieve the effects of a focal length of 16.9 mm, an overall length of the assembly of 20 mm, a field angle of 65 °, and an Eye box of 9 mm × 9 mm.

As can be seen from the two examples, the fresnel lens assembly provided by the embodiments of the present disclosure can effectively reduce the thickness of the lens assembly (the thickness is less than or equal to 20 mm), and can achieve a higher luminous efficacy (the luminous efficacy is greater than or equal to 80%). In addition, according to the fresnel lens assembly provided by the embodiment of the disclosure, after light passes through the light incident surface of the sawtooth-shaped structure, the light can be refracted once inside the sawtooth-shaped structure, so that the light convergence effect is realized; after the light passes through the round angle position on the side surface, the light can be refracted twice in the sawtooth structure to form stray light different from a light path of the light passing through the light incident surface. Wherein, stray light elimination structure can shelter from or absorb the light through side and fillet position, shelters from or absorbs the stray light that forms through the invalid face promptly to prevent stray light from getting into user's field of vision by fresnel lens outgoing, consequently can avoid stray light to the interference of normal light, thereby can improve display effect, and then can improve user and use experience.

In some embodiments, as shown in fig. 7 and 9, an air gap is provided between some adjacent fresnel lenses in the plurality of fresnel lenses.

Some air gaps are arranged between the adjacent Fresnel lenses, the specific width of the air gaps can be adjusted, the focal length and the thickness of the Fresnel lens assembly are adjusted, clear display images are formed in the visual field of a user, the display effect is improved, and the use experience of the user is improved.

The embodiment of the present disclosure further provides a virtual reality display apparatus, where the virtual reality display apparatus includes the fresnel lens assembly provided in any of the above embodiments, and the implementation principle and the technical effect of the virtual reality display apparatus are the same as those of the fresnel lens and the fresnel lens assembly, and are not described herein again. It can be understood that the fresnel lens assembly provided in the embodiments of the present disclosure may be applied to a virtual reality display device, and may also be applied to an augmented reality display device, and other near-eye display devices such as a pair of dimming glasses, which are not listed here.

It is to be understood that the above embodiments are merely exemplary embodiments that are employed to illustrate the principles of the present disclosure, and that the present disclosure is not limited thereto. It will be apparent to those skilled in the art that various changes and modifications can be made therein without departing from the spirit and scope of the disclosure, and these are to be considered as the scope of the disclosure.