CN113448085A

CN113448085A - Near-to-eye display device and glasses

Info

Publication number: CN113448085A
Application number: CN202010213415.2A
Authority: CN
Inventors: 陈志东; 李宁; 张�杰
Original assignee: Shenzhen Pencil Vision Technology Co ltd
Current assignee: Shenzhen Pencil Vision Technology Co ltd
Priority date: 2020-03-24
Filing date: 2020-03-24
Publication date: 2021-09-28

Abstract

The embodiment of the invention provides a near-eye display device and glasses. Wherein the near-eye display device comprises: a waveguide sheet that totally reflects incident light through the inside thereof; a transparent scattering film for scattering the light totally reflected by the waveguide sheet; and the reflective volume holographic element selectively reflects or transmits the light scattered by the transparent scattering film. The embodiment of the invention increases the propagation distance of light rays and realizes the folding of an optical path by arranging the waveguide sheet, and is matched with the transparent scattering film, thereby being beneficial to increasing the imaging range of images and further being beneficial to increasing the visual angle and the exit pupil; in addition, the reflective volume hologram element adopted by the embodiment of the invention is of a film-shaped structure, which is beneficial to reducing the volume of the near-eye display device, enabling the near-eye display device to be thinner and lighter, and further being beneficial to improving the user experience.

Description

Near-to-eye display device and glasses

Technical Field

The embodiment of the invention relates to the field of optical instruments, in particular to a near-to-eye display device and glasses.

Background

Near-eye Display technology originated in Head Mount Display (HMD), which was proposed in the 80 s, mainly for military applications, incorporating computer technology including computer vision. With the maturity of semiconductor technology and optical technology, it starts to develop electronic technology, digital image processing technology and precision optical manufacturing technology in commercial aspects, and the near-to-eye display technology gradually enters people's daily life from the military field.

Near-eye Display devices (Near-eye Display devices) are considered to be a fifth generation emerging Display media from movies, television, computers, mobile phones, and beyond. It builds a display right in front of the user's field of vision, on which various data contents can be shown, including images, photographs, web pages, e-mails, digital maps, etc. Compared with a smart phone, a smart tablet computer, a notebook computer and a desktop computer, the near-eye display device can use a very small display screen in combination with an optical projection technology to project a larger-sized screen in front of the eyes of a user to provide picture information with a larger viewing angle.

However, the use sensitivity of the near-eye display device is still to be improved

Disclosure of Invention

The embodiment of the invention provides a near-eye display device and glasses, which are beneficial to enabling the near-eye display device to be thinner and lighter and increasing the field angle, so that the user experience is improved.

To solve the above problem, an embodiment of the present invention provides a near-eye display device, including: a waveguide sheet that totally reflects incident light through the inside thereof; a transparent scattering film for scattering the light totally reflected by the waveguide sheet; and the reflective volume holographic element selectively reflects or transmits the light scattered by the transparent scattering film.

Optionally, the waveguide sheet has a first inner wall and a second inner wall opposite to each other, a first outer surface opposite to the first inner wall, and a second outer surface opposite to the second inner wall, and the incident light is totally reflected on the second inner wall of the waveguide sheet to form reflected light projected onto the first inner wall.

Optionally, the transparent scattering film is disposed on the first outer surface of the waveguide sheet.

Optionally, the reflective volume hologram element is disposed in non-contact with the second outer surface of the waveguide sheet.

Optionally, the near-eye display device further includes: and the projection module is used for generating incident light.

Optionally, the projection module is a short-focus projection module.

Optionally, the thickness of the waveguide sheet is 0.5mm to 6 mm.

Optionally, the thickness of the reflective volume hologram element is less than or equal to 200 μm.

Optionally, the material of the reflective volume hologram element comprises a silver salt material, a photorefractive polymer or dichromated gelatin.

Optionally, the reflective volume hologram element transmits light scattered by the transparent scattering film; the near-eye display device further includes: a phase retardation device for rotating a polarization direction of light transmitted by the reflective volume hologram element; the polarization direction of the polarization reflection device is different from the polarization direction of light emitted by the phase delay device for the first time, and when the polarization direction of the light emitted by the phase delay device is the same as the polarization direction of the polarization reflection device, the polarization reflection device transmits the light emitted by the phase delay device; when the polarization direction of the light emitted by the phase delay device is different from the polarization direction of the polarized reflection device, the polarized reflection device reflects the light emitted by the phase delay device.

Optionally, the reflective volume hologram element transmits light scattered by the transparent scattering film; the near-eye display device further includes: a phase retardation device for rotating a polarization direction of light transmitted by the reflective volume hologram element; and the partial transmission and partial reflection device is used for performing partial transmission and partial reflection on light emitted by the phase delay device.

Optionally, the reflective volume hologram element reflects light scattered by the transparent scattering film; the near-eye display device further includes: a phase retardation device for rotating a polarization direction of the light reflected by the reflective volume hologram element; a polarization reflection device, the polarization direction of which is different from the polarization direction of the light emitted by the phase retardation device for the first time, and the polarization reflection device transmits the light reflected by the reflective volume hologram element when the polarization direction of the light reflected by the reflective volume hologram element is the same as the polarization direction of the polarization reflection device; and when the polarization direction of the light reflected by the reflective volume hologram element is different from the polarization direction of the polarization reflection device, the polarization reflection device reflects the light reflected by the reflective volume hologram element.

Optionally, the reflective volume hologram element reflects light scattered by the transparent scattering film; the near-eye display device further includes: a phase retardation device for rotating a polarization direction of the light reflected by the reflective volume hologram element; and the partial transmission and partial reflection device is used for performing partial transmission and partial reflection on light emitted by the phase delay device.

Optionally, the phase delay device is a (1/4+ n pi) phase delay device; wherein n is an integer.

Optionally, the near-eye display device further includes: and the polarization film transmits the light emitted by the polarized reflection device when the polarization direction of the light emitted by the polarized reflection device is the same as the polarization direction of the polarization film.

Optionally, the near-eye display device further includes: a polarizing film having a polarization direction different from that of the first light emitted from the phase retarder, and transmitting the partially transmissive partially reflective device transmitted light when the polarization direction of the partially transmissive partially reflective device transmitted light is the same as that of the polarizing film.

Optionally, the reflective volume hologram element transmits light scattered by the transparent scattering film; the near-eye display device further includes: and the shading element covers the transparent scattering film.

Optionally, the reflective volume hologram element reflects light scattered by the transparent scattering film; the near-eye display device further includes: and the shading element covers the surface of the reflection type volume holographic element back to the waveguide sheet.

Correspondingly, the embodiment of the invention also provides a pair of glasses, which comprises: the embodiment of the invention provides a near-eye display device.

Compared with the prior art, the technical scheme of the embodiment of the invention has the following advantages:

the near-eye display device provided by the embodiment of the invention comprises: a waveguide sheet that totally reflects incident light through the inside thereof; a transparent scattering film for scattering the light totally reflected by the waveguide sheet; the reflective volume holographic element selectively reflects or transmits the light scattered by the transparent scattering film, so that emergent light is formed and enters pupils of human eyes, and the emergent light can be captured by the human eyes to realize near-to-eye display; the invention increases the propagation distance of light rays and realizes the folding of an optical path by arranging the waveguide sheet, and is matched with the transparent scattering film, thereby being beneficial to enlarging the imaging range of images and further being beneficial to enlarging the visual angle and the exit pupil; moreover, the reflective volume hologram element is generally a film-shaped structure, which is beneficial to reducing the volume of the near-to-eye display device, so that the near-to-eye display device is thinner and lighter, and the two aspects are beneficial to improving the user experience.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings 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 embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the provided drawings without creative efforts.

FIG. 1 is a schematic diagram of a near-eye display device according to an embodiment of the present invention;

FIG. 2 is a schematic diagram of a near-eye display device according to another embodiment of the present invention;

FIG. 3 is a schematic diagram of a light propagation path of the near-eye display device shown in FIG. 2;

fig. 4 is a schematic diagram of the change in the polarization state of light in the light propagation path shown in fig. 3.

Detailed Description

As is known from the background art, the use sensitivity of the near-eye display device still needs to be improved.

In particular, in some near-eye display device implementations, a near-eye display device (such as a head-mounted display) may include various optical components disposed within the device, for example: microdisplays, lens assemblies, and/or other optical elements, etc. These optical components (e.g., lens components) are generally bulky, taking up a lot of space, which in turn tends to result in a bulky and heavy near-eye display device; also, near-eye display devices will typically be configured as eyewear worn by a user, such as: AR (Augmented Reality) glasses, a large volume and weight of a near-eye display device easily result in poor user experience and use experience.

In order to solve the technical problem, an embodiment of the present invention provides a near-eye display device, including: a waveguide sheet that totally reflects incident light through the inside thereof; a transparent scattering film for scattering the light totally reflected by the waveguide sheet; and the reflective volume holographic element selectively reflects or transmits the light scattered by the transparent scattering film.

In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in detail below.

Referring to fig. 1, a schematic structural diagram of a near-eye display device according to an embodiment of the present invention is shown.

As shown in fig. 1, the near-eye display device includes: a waveguide sheet 2 for totally reflecting incident light through the inside thereof; a transparent scattering film 3 for scattering the light totally reflected by the waveguide sheet 2; and a reflective volume hologram element 5 for selectively reflecting or transmitting the light scattered by the transparent scattering film 3.

The waveguide sheet 2 is used for totally reflecting incident light through the inside thereof, thereby realizing transverse transmission of light, increasing the propagation distance of light, and further realizing folding of a light path. Specifically, when incident light enters the waveguide sheet 2 and is incident on the inner wall of the waveguide sheet 2, Total Internal Reflection (TIR) occurs, so that the incident light is confined to propagate in the waveguide sheet 2.

In this embodiment, the waveguide sheet 2 is a planar dielectric optical waveguide, and the material of the waveguide sheet 2 may include silicon oxide, silicon, and other materials. In other embodiments, the waveguide sheet may also be an optical waveguide of other types and structures, and the material of the waveguide sheet may accordingly also be other suitable materials.

In this embodiment, the waveguide sheet 2 has a first inner wall 21 and a second inner wall 22 opposite to each other, and a first outer surface (not labeled) opposite to the first inner wall 21 and a second outer surface (not labeled) opposite to the second inner wall 22, and the incident light is totally reflected on the second inner wall 22 of the waveguide sheet 2 to form reflected light projected onto the first inner wall 21.

In this embodiment, by transversely transmitting light in the waveguide sheet 2, the size occupied by the near-eye display device is small while a large light propagation distance is achieved.

Therefore, the thickness of the waveguide sheet 2 should not be too small, otherwise, the effect of increasing the propagation distance of the incident light by the waveguide sheet 2 is not obvious; however, the thickness of the waveguide sheet 2 is not necessarily too large, and the volume and weight of the near-eye display device are likely to increase, and it is difficult to make the near-eye display device thinner. For this reason, in the present embodiment, the thickness of the waveguide sheet 2 is 0.5mm to 6 mm.

In this embodiment, the near-eye display device further includes: the projection module 1 is used for generating incident light.

The projection module 1 is used for converting a virtual picture into a projected image, so that the image can be projected into the waveguide sheet 2 by means of projection, and the incident light generated by the picture propagates in the waveguide sheet 2.

The farther the distance that the image that projection module 1 projected propagated is, the bigger the projected image size is also, compare with directly with the picture projection to on the transparent diffusion barrier 3, this embodiment is through making the incident light that projection module 1 produced project to in the waveguide piece 2, the rethread waveguide piece 2 transmits to on the transparent diffusion barrier 3, be favorable to increasing the propagation distance of light, and then be favorable to increasing the picture size that finally enters into people's eyes, the corresponding user experience that is favorable to improving.

In particular, the projection module 1 may generally comprise a laser, a lens system, a microdisplay, or the like.

It should be noted that, in order to ensure that the incident light generated by the projection module 1 can be propagated in the waveguide sheet 2 in a total reflection manner, the position relationship between the projection module 1 and the waveguide sheet 2 needs to be set reasonably, so that the coupling angle of the incident light generated by the projection module 1 can satisfy the condition that the light is totally reflected on the second inner wall 22 of the waveguide sheet 2.

In this embodiment, the projection module 1 is a short-focus projection module. Short focus projection modules typically include a short focus projector having a very short throw ratio, where the throw ratio refers to the ratio of the distance between the projector and the screen to the screen size, and can project a larger size picture in a shorter distance, for example: the throw ratio of a short focus projection module is typically less than 1 and may even be less than 0.6.

In the embodiment, the short-focus projection module is adopted as the projection module 1, so that a picture with a larger size can be projected within a shorter distance, and finally the picture entering human eyes through the reflective volume hologram element 5 has a larger size, which is beneficial to increasing the field angle of the near-to-eye display device and correspondingly improving the use sensitivity; moreover, compared with the scheme of using the microdisplay to display a picture with a larger size, the microdisplay generally needs to make the microdisplay larger in size, which is easy to increase the size and volume of the near-eye display device.

The transparent scattering film 3 is used for scattering the light totally reflected by the waveguide sheet 2. In this embodiment, the transparent scattering film 3 scatters the light totally reflected by the waveguide 2, so as to form a real image on the transparent scattering film 3, and convert the image formed by the incident light into a light coaxial with the reflective volume hologram 5, so as to reflect or transmit the image to human eyes through the reflective volume hologram 5, and in addition, the transparent scattering film 3 can also diffuse the incident light, so as to increase the optical path and accordingly increase the exit pupil.

In this embodiment, the transparent scattering film 3 is disposed on the first outer surface of the waveguide sheet 2. In this embodiment, the incident light is totally reflected on the second inner wall 22 of the waveguide sheet 2 to form totally reflected light projected onto the first inner wall 21, and therefore, the totally reflected light projected onto the first inner wall 21 is scattered by the transparent scattering film 3.

In this embodiment, the transparent scattering film 3 having a specific scattering efficiency range may be selected, so that the light energy utilization rate of the transparent scattering film 3 is not too small, and thus, light rays finally entering human eyes are more, which is correspondingly beneficial to the imaging quality and the user experience.

It should be noted that the refractive index of the material of the transparent scattering film 3 needs to be close to or the same as the refractive index of the waveguide sheet 2, so that when the totally reflected light projected onto the first inner wall 21 of the waveguide sheet 2 hits the first inner wall 21, the totally reflected light projected onto the first inner wall 21 is transmitted onto the transparent scattering film 3 without being totally reflected on the first inner wall 21, and the transparent scattering film 3 can scatter the totally reflected light projected onto the first inner wall 21.

In the present embodiment, the transparent scattering film 3 and the waveguide sheet 2 are disposed in a contact manner as an example. In other embodiments, the transparent scattering film and the waveguide sheet may not be in direct contact, and other dielectric layers (not shown) may be disposed between the transparent scattering film and the waveguide sheet, for example: and the bonding layer is used for fixing and protecting the transparent scattering film, so that the stability and the reliability of the near-eye display device are improved. Accordingly, in order to ensure that light can be transmitted to the transparent diffusion film 3, the refractive index of the adhesive layer is equal to or the same as that of the waveguide sheet 2 and that of the transparent diffusion film 3.

In this embodiment, the near-to-eye display device is used for realizing near-to-eye display of Augmented Reality (Augmented Reality), and the transparent scattering film 3 is made of a light-transmitting material, so that external light can enter pupils of human eyes, and perspective (see-through) of an external environment is correspondingly realized, thereby realizing superposition of real world and virtual information.

Therefore, in the present embodiment, the transparent scattering film 3 with a specific light transmittance can be selected to improve the perspective effect to the external environment, such as: the occurrence of the phenomenon that the external light entering the pupils of the human eyes is too dark is prevented. The present embodiment does not limit the light transmittance of the transparent diffusion film 3.

In this embodiment, the transparent scattering film 3 is a film-like structure, and the thickness of the transparent scattering film 3 is generally small, which is beneficial to reducing the volume of the near-eye display device and further beneficial to optimizing the user experience.

In this embodiment, the transparent scattering film 3 may be a volume holographic element or a micro-nano structure scattering film.

The reflective volume holographic element 5 is used for selectively transmitting or reflecting the light scattered out of the transparent scattering film 3, so that the light transmitted or reflected by the reflective volume holographic element 5 is emitted into the pupil of the human eye, and near-to-eye display is realized; moreover, the reflective volume hologram element 5 is generally a film-shaped structure, which is not only beneficial to reducing the volume of the near-to-eye display device and making the near-to-eye display device thinner and lighter, and further beneficial to improving the user experience, but also beneficial to being integrated with a multi-layer film structure, and is easy to realize the assembly and manufacture of the near-to-eye display device.

Specifically, the reflective volume hologram element 5 has an angle selectivity with respect to light according to a volume Bragg effect (Bragg Diffraction), and when an angle of light projected onto the reflective volume hologram element 5 satisfies a Bragg matching condition, the reflective volume hologram element 5 reflects the light and enlarges an image into a virtual image; when the angle of the light projected onto the reflective volume hologram element 5 does not satisfy the bragg matching condition, the reflective volume hologram element 5 transmits the light.

The light scattered out of the transparent scattering film 3 has a plurality of directions. As an example, in the present embodiment, the reflective volume hologram element 5 reflects the scattered light satisfying the angle selection condition, and the reflective volume hologram element 5 enlarges the real image formed on the transparent scattering film 3 into a virtual image at a far distance, so that the virtual image can be positioned in a range observed by human eyes, thereby realizing near-eye display. Specifically, in this embodiment, the reverse extension lines of the light beams reflected by the reflective volume hologram element 5 converge in front of the eyes of the user to form image points of a virtual image, and the image points are collected to form a picture observed by the eyes of the user.

In this embodiment, the reflective volume hologram element 5 is manufactured by a holographic interference method, and the reflective volume hologram element 5 may be a reflective volume hologram lens.

In the present embodiment, the material of the reflective volume hologram element 5 may include silver salt material, photorefractive polymer, dichromated gelatin, or the like.

The greater the thickness of the reflective volume hologram element 5, the smaller the angular sensitivity of the reflective volume hologram element 5, that is, the narrower the angular range of the light that can be reflected by the reflective volume hologram element 5, and the more easily the imaging quality is degraded. For this reason, in the present embodiment, the thickness of the reflective volume hologram element 5 is less than or equal to 200 μm.

In this embodiment, the reflective volume hologram element 5 and the second outer surface of the waveguide sheet 2 are provided in a non-contact manner. By disposing the reflective volume hologram element 5 in non-contact with the second outer surface of the waveguide sheet 2, it is possible to cause the incident light to be totally reflected on the second inner wall 22 of the waveguide sheet 2 when the incident light enters the inside of the waveguide sheet 2 by disposing an optical medium layer between the reflective volume hologram element 5 and the second outer surface of the waveguide sheet 2.

Specifically, in the present embodiment, a space gap 8 is provided between the reflective volume hologram element 5 and the second outer surface of the waveguide sheet 2. The refractive index of air is very low, and the provision of the space gap 8 is advantageous for ensuring that the incident light can be totally reflected at the second inner wall 22. In other embodiments, another optical medium layer with a lower refractive index may be disposed between the reflective volume hologram element 5 and the second outer surface of the waveguide sheet 2, so that the incident light can be totally reflected on the second inner wall of the waveguide sheet.

It should be noted that, in order to ensure that the reflective volume hologram element 5 can receive the light scattered by the transparent scattering film 3, so as to selectively transmit or reflect the light scattered by the transparent scattering film 3, in this embodiment, the thickness of the waveguide sheet 2 and the distance between the reflective volume hologram element 5 and the second outer surface of the waveguide sheet 2 need to be set reasonably, so that the transparent scattering film 3 can be located within the focal length range of the reflective volume hologram element 5. Specifically, in this embodiment, the transparent scattering film 3 is located within the focal plane of the reflective volume hologram element 5.

Wherein the transparent scattering film 3 is located in the focal plane range of the reflective volume hologram element 5, which means that: the transparent scattering film 3 is located on the focal plane of the reflective volume hologram element 5, or the distance between the transparent scattering film 3 and the reflective volume hologram element 5 is smaller than the distance of the focal plane of the reflective volume hologram element 5.

In this embodiment, the near-eye display device further includes: and light-transmitting base layers 4 provided on the upper and lower surfaces of the reflective volume hologram element 5.

The reflective volume hologram element 5 is a film-like structure, the reflective volume hologram element 5 is thin, and the light-transmitting substrate layer 4 is provided on the upper surface and the lower surface of the reflective volume hologram element 5, so that the light-transmitting substrate layer 4 can fix and support the reflective volume hologram element 5, and the light-transmitting substrate layer 4 can protect the reflective volume hologram element 5, thereby being beneficial to reducing the influence of the external environment on the reflective volume hologram element 5.

The light-transmitting substrate layer 4 is a light-transmitting material, thereby preventing influence on the transmission of light. In this embodiment, the material of the light-transmitting substrate layer 4 may be a light-transmitting material such as glass or optical resin.

In this embodiment, the reflective volume hologram element 5 reflects light scattered by the transparent scattering film 3; the near-eye display device further includes: and a light shielding element (not shown) covering the surface of the reflective volume hologram element 5 opposite to the waveguide plate 2.

In this embodiment, the reflective volume hologram 5 reflects the scattered light, so that when a user uses the near-eye display device, the human eye is located on a side of the transparent scattering film 3 facing away from the waveguide 2, external light is transmitted from a side of the reflective volume hologram 5 facing away from the waveguide 2 and enters the human eye, and the light shielding element is disposed on a surface of the reflective volume hologram 5 facing away from the waveguide 2, so as to block the external light, thereby realizing switching between augmented reality and Virtual Reality (VR).

Specifically, the shading element may be an electronic valve or a mask.

Fig. 2 is a schematic structural diagram of another embodiment of a near-eye display device according to the present invention. The same parts of the embodiments of the present invention as those of the previous embodiments are not described herein again, and the differences between the embodiments of the present invention and the previous embodiments are:

the reflective volume hologram 51 transmits light scattered by the transparent scattering film 31.

Specifically, the reflective volume hologram element 51 has an angle selectivity with respect to light, and is capable of transmitting light that does not satisfy the bragg matching condition, that is, the reflective volume hologram element 51 projects light that does not satisfy the bragg matching condition among the light scattered by the transparent scattering film 31, so that the light is emitted from a side of the reflective volume hologram element 51 facing away from the waveguide sheet 21 and enters the human eye.

Accordingly, external light is transmitted from the side of the transparent diffusion film 31 facing away from the waveguide sheet 21.

Therefore, by utilizing the characteristic of the reflective volume hologram 51 of selectively reflecting or transmitting the light scattered by the transparent scattering film 31, the relative position of the near-eye display device and the external environment can be flexibly adjusted as needed in practical applications.

The near-eye display device further includes: a phase retarder 6 for rotating the polarization direction of the light transmitted by the reflective volume hologram 51; the polarization reflecting device 7, the polarization direction of the polarization reflecting device 7 is different from the polarization direction of the light emitted by the phase retarding device 6 for the first time, and when the polarization direction of the light emitted by the phase retarding device 6 is the same as the polarization direction of the polarization reflecting device 7, the polarization reflecting device 7 transmits the light emitted by the phase retarding device 6; when the polarization direction of the light emitted by the phase retarder 6 is different from the polarization direction of the polarization reflection device 7, the polarization reflection device 7 reflects the light emitted by the phase retarder 6.

The phase retarding device 6 rotates the polarization direction of the light transmitted by the reflective volume hologram 51, so that after the light transmitted by the reflective volume hologram 51 is emitted after passing through the phase retarding device 6 for the first time, the polarization direction of the light emitted by the phase retarding device 6 is different from the polarization direction of the polarization reflecting device 7 through the phase retarding device 6, and accordingly the polarization reflecting device 7 reflects the light emitted by the phase retarding device 6; then, after passing through the phase retarder 6, the polarization direction of the light reflected by the polarization reflection device 7 is rotated, and then the light emitted by the phase retarder 6 is reflected by the reflective volume hologram 51, and after passing through the phase retarder 6 again, the polarization direction of the light emitted by the phase retarder 6 may be the same as the polarization direction of the polarization reflection device 7, so that the light is transmitted through the polarization reflection device 7.

Therefore, in this embodiment, by providing the phase retarder 6 and the polarization reflector 7, the path of light propagation is increased, and the light path is folded, so that the focal length of the volume hologram lens is increased under the condition that the near-to-eye display device is thin, and further the effective aperture is increased, and accordingly the field of view (FOV) is increased and the imaging quality is improved, and meanwhile, the thicknesses of the phase retarder 6 and the polarization reflector 7 are both small, so that the size and the weight of the near-to-eye display device are also reduced, and further the use sensitivity is improved.

As an example, in the present embodiment, the thickness of the phase delay device 6 is less than 500 micrometers; the thickness of the polarization reflection device 7 is less than 500 micrometers; the thicknesses of the phase retarding device 6 and the polarization reflecting device 7 are both small.

In the present embodiment, the phase delay device 6 is a (1/4+ n π) phase delay device; wherein n is an integer.

As an example, in the present embodiment, the phase delay device 6 is a quarter phase delay device, such as: a quarter-wave plate. The quarter-phase delay device can realize the conversion of circularly polarized light and linearly polarized light.

As an example, in the present embodiment, the polarization reflective device 7 transmits P-polarized light and reflects S-polarized light.

As an example, fig. 3 shows a schematic diagram of a propagation path of light in the present embodiment, and fig. 4 is a schematic diagram of a change in polarization state in the propagation path of light shown in fig. 3. The following describes the propagation path of the light and the change of the polarization state of the light in this embodiment with reference to fig. 3 and 4.

As an example, specifically, light is scattered by the transparent scattering film 31, and then the reflective volume hologram 51 transmits the light scattered by the transparent scattering film 31, in this case, the reflective volume hologram 51 transmits the light as left-handed circularly polarized light; then, after the transmitted light of the reflective volume hologram 51 passes through the phase retardation device 6 for the first time (as shown by I in fig. 4), the left-handed circularly polarized light becomes S polarized light; the phase delay device 6 emits light for the first time as S-polarized light, so that the S-polarized light is reflected by the polarization reflection device 7; the light reflected by the polarization reflection device 7 passes through the phase delay device 7 (shown as II in fig. 4) for the second time, and then becomes left circularly polarized light; the phase delay device 6 reflects the light emitted for the second time by the reflective volume hologram 5, and accordingly, the rotating direction of the left-handed circularly polarized light is changed after the left-handed circularly polarized light is reflected, and the left-handed circularly polarized light is changed into right-handed circularly polarized light; after the right-handed circularly polarized light formed by reflection of the reflective volume hologram element 5 passes through for the third time (as shown in III in fig. 4), the right-handed circularly polarized light is converted into P-polarized light; the polarization direction of the light emitted from the phase retarder 6 for the third time is the same as the polarization direction of the polarization reflection device 7, so that the light is transmitted by the polarization reflection device 7.

It should be noted that the above description of the change of the polarization state of the light in the present embodiment is only an example. In other embodiments, the phase retarding device and the polarization reflecting device can be integrally rotated, and the effect of increasing the optical path length can also be achieved.

In the present embodiment, the polarization reflection device 7 and the phase retardation device 6 are provided as a contact as an example. In other embodiments, other dielectric layers (e.g., adhesive layers) may be disposed between the polarization reflective device and the phase retardation device, and in this embodiment, the refractive indexes of any two film layers in contact are equal or identical in order to reduce the influence on the optical path.

In this embodiment, a light-transmitting substrate layer 41 is also disposed on a surface of the polarization reflection device 7 facing away from the phase retardation device 6, and the light-transmitting substrate layer 41 is used to protect the polarization reflection device 7.

In this embodiment, the near-eye display device further includes: the polarizing film 9 transmits the light emitted from the polarization reflection device 7 when the polarization direction of the light emitted from the polarization reflection device 7 is the same as the polarization direction of the polarizing film 9.

Through setting up the polarization membrane 9 to filter out the light that is different with the polarization direction of polarized reflection device 7, and then be favorable to reducing stray light and interference light.

Specifically, in this embodiment, the polarizing film 9 is a P-polarizing film.

In this embodiment, the reflective volume hologram 51 transmits light scattered by the transparent scattering film 31; the near-eye display device further includes: and a light shielding element 10 covering the transparent scattering film 31.

The reflective volume hologram 51 transmits light scattered by the transparent scattering film 31, so that, in this embodiment, when a user uses the near-eye display device, a human eye is located on a side of the reflective volume hologram 51 facing away from the waveguide 21, external light is transmitted from the side of the transparent scattering film 31 facing away from the waveguide 21 and enters the human eye, and the light shielding element 10 is disposed on the transparent scattering film 31, so that blocking of the external light is realized, and switching between augmented reality and Virtual Reality (VR) is realized.

In particular, the shading element can be an electronic valve or a shade.

As an example, in the present embodiment, the entire thickness of the near-eye display device is 3mm to 20mm, the thickness of the near-eye display device is small, and the near-eye display device is thin and light.

In other embodiments, the overall thickness of the near-eye display device may also be within other value ranges, and the embodiment is not limited herein.

Accordingly, the present invention further provides a near-eye display device according to an embodiment, and the same points of the embodiment of the present invention as those of the previous embodiment are not described herein again, but the present embodiment differs from the previous embodiment in that:

the reflective volume holographic element transmits the light scattered by the transparent scattering film; the near-eye display device further includes: a phase retardation device for rotating a polarization direction of light transmitted by the reflective volume hologram element; and the partial transmission and partial reflection device is used for performing partial transmission and partial reflection on light emitted by the phase delay device.

In this embodiment, by providing the phase delay device and the partial transmission partial reflection device, the partial transmission partial reflection device can perform multiple reflections on light emitted by the phase delay device, which is beneficial to increasing the propagation path of the light, correspondingly beneficial to increasing the effective aperture, and further beneficial to increasing the field angle.

In this embodiment, the near-eye display device further includes: a polarizing film having a polarization direction different from that of the first light emitted from the phase retarder, and transmitting the partially transmissive partially reflective device transmitted light when the polarization direction of the partially transmissive partially reflective device transmitted light is the same as that of the polarizing film.

The polarizing film is used for filtering out light with a polarization direction different from that of the polarizing film, thereby being beneficial to reducing interference light and stray light. In this embodiment, the polarization direction of the polarization film is different from the polarization direction of the light emitted by the phase retarder for the first time, and the partially transmissive partially reflective device does not change the polarization direction of the light, so that the polarization direction of the polarization film is different from the polarization direction of the light emitted by the partially transmissive partially reflective device for the first time, so that the light emitted by the partially transmissive partially reflective device for the first time can be filtered, and stray light and interference light can be reduced.

In this embodiment, the polarizing film is a P-polarizing film.

the reflective volume holographic element reflects the light scattered by the transparent scattering film; the near-eye display device further includes: a phase retardation device for rotating a polarization direction of the light reflected by the reflective volume hologram element; a polarization reflection device, the polarization direction of which is different from the polarization direction of the light emitted by the phase retardation device for the first time, and the polarization reflection device transmits the light reflected by the reflective volume hologram element when the polarization direction of the light reflected by the reflective volume hologram element is the same as the polarization direction of the polarization reflection device; and when the polarization direction of the light reflected by the reflective volume hologram element is different from the polarization direction of the polarization reflection device, the polarization reflection device reflects the light reflected by the reflective volume hologram element.

When the reflective volume holographic element reflects the light scattered by the transparent scattering film, the phase delay device and the polarization reflection device are arranged, so that the folding of the light path and the increase of the optical path are correspondingly facilitated, the effective aperture is increased, and the field angle is increased.

For specific description of the phase retardation device and the polarization reflection device, reference may be made to the corresponding description of the foregoing embodiments, and the description of the present embodiment is not repeated here.

In this embodiment, the near-eye display device further includes: and the polarization film transmits the light emitted by the polarized reflection device when the polarization direction of the light emitted by the polarized reflection device is the same as that of the polarization film.

This embodiment is through setting up the polarization film, be favorable to reducing stray light and interference light, and then improve the image quality.

For the specific description of the polarizer film, reference may be made to the corresponding description of the foregoing embodiments, which are not repeated herein.

the reflective volume holographic element reflects the light scattered by the transparent scattering film; the near-eye display device further includes: a phase retardation device for rotating a polarization direction of the light reflected by the reflective volume hologram element; and the partial transmission and partial reflection device is used for performing partial transmission and partial reflection on light emitted by the phase delay device.

The polarizing film is used for filtering out light with a polarization direction different from that of the polarizing film, thereby being beneficial to reducing interference light and stray light.

In this embodiment, the polarizing film is a P-polarizing film.

For specific description of the embodiments of the present invention, reference may be made to the related description of the foregoing embodiments, and the description of the embodiments is not repeated herein.

As can be seen from the foregoing embodiments, the near-eye display device provided in the embodiments of the present invention is beneficial to increasing the viewing angle and the exit pupil, and the near-eye display device provided in the embodiments of the present invention has a smaller volume and weight, and is lighter and thinner.

Specifically, in this embodiment, the glasses may be AR glasses or VR glasses.

The eyeglasses may also include frame, temple bars, and the like.

Although the present invention is disclosed above, the present invention is not limited thereto. Various changes and modifications may be effected therein by one skilled in the art without departing from the spirit and scope of the invention as defined in the appended claims.

Claims

1. A near-eye display device, comprising:

a waveguide sheet that totally reflects incident light through the inside thereof;

a transparent scattering film for scattering the light totally reflected by the waveguide sheet;

and the reflective volume holographic element selectively reflects or transmits the light scattered by the transparent scattering film.

2. The near-eye display device of claim 1, wherein the waveguide sheet has a first inner wall and a second inner wall opposite to each other, and a first outer surface opposite to the first inner wall and a second outer surface opposite to the second inner wall, and wherein the incident light is totally reflected on the second inner wall of the waveguide sheet to form reflected light projected onto the first inner wall.

3. The near-eye display device of claim 2, wherein the transparent scattering film is disposed on the first outer surface of the waveguide sheet.

4. The near-eye display device of claim 2, wherein the reflective volume hologram element is disposed in non-contact with the second outer surface of the waveguide sheet.

5. The near-eye display device of claim 1, further comprising: and the projection module is used for generating incident light.

6. The near-eye display device of claim 5, wherein the projection module is a short focus projection module.

7. The near-eye display device of claim 1, wherein the waveguide sheet has a thickness of 0.5mm to 6 mm.

8. The near-eye display device of claim 1, wherein the reflective volume holographic element has a thickness of less than or equal to 200 μ ι η.

9. The near-eye display device of claim 1, wherein the material of the reflective volume hologram element comprises a silver salt material, a photorefractive polymer, or dichromated gelatin.

10. The near-eye display device of claim 1, wherein the reflective volume hologram element transmits light scattered out of the transparent scattering film;

the near-eye display device further includes: a phase retardation device for rotating a polarization direction of light transmitted by the reflective volume hologram element; the polarization direction of the polarization reflection device is different from the polarization direction of light emitted by the phase delay device for the first time, and when the polarization direction of the light emitted by the phase delay device is the same as the polarization direction of the polarization reflection device, the polarization reflection device transmits the light emitted by the phase delay device; when the polarization direction of the light emitted by the phase delay device is different from the polarization direction of the polarized reflection device, the polarized reflection device reflects the light emitted by the phase delay device.

11. The near-eye display device of claim 1, wherein the reflective volume hologram element transmits light scattered out of the transparent scattering film;

the near-eye display device further includes: a phase retardation device for rotating a polarization direction of light transmitted by the reflective volume hologram element; and the partial transmission and partial reflection device is used for performing partial transmission and partial reflection on light emitted by the phase delay device.

12. The near-eye display device of claim 1, wherein the reflective volume hologram element reflects light scattered out of the transparent scattering film;

the near-eye display device further includes: a phase retardation device for rotating a polarization direction of the light reflected by the reflective volume hologram element; a polarization reflection device, the polarization direction of which is different from the polarization direction of the light emitted by the phase retardation device for the first time, and the polarization reflection device transmits the light reflected by the reflective volume hologram element when the polarization direction of the light reflected by the reflective volume hologram element is the same as the polarization direction of the polarization reflection device; and when the polarization direction of the light reflected by the reflective volume hologram element is different from the polarization direction of the polarization reflection device, the polarization reflection device reflects the light reflected by the reflective volume hologram element.

13. The near-eye display device of claim 1, wherein the reflective volume hologram element reflects light scattered out of the transparent scattering film;

the near-eye display device further includes: a phase retardation device for rotating a polarization direction of the light reflected by the reflective volume hologram element; and the partial transmission and partial reflection device is used for performing partial transmission and partial reflection on light emitted by the phase delay device.

14. The near-eye display device of any one of claims 10-13, wherein the phase retarding device is a (1/4+ n pi) phase retarding device; wherein n is an integer.

15. The near-eye display device of claim 10 or 12, further comprising: and the polarization film transmits the light emitted by the polarized reflection device when the polarization direction of the light emitted by the polarized reflection device is the same as the polarization direction of the polarization film.

16. The near-eye display device of claim 11 or 13, further comprising: a polarizing film having a polarization direction different from that of the first light emitted from the phase retarder, and transmitting the partially transmissive partially reflective device transmitted light when the polarization direction of the partially transmissive partially reflective device transmitted light is the same as that of the polarizing film.

17. The near-eye display device of claim 2, wherein the reflective volume hologram element transmits light scattered out of the transparent scattering film; the near-eye display device further includes: and the shading element covers the transparent scattering film.

18. The near-eye display device of claim 3, wherein the reflective volume hologram element reflects light scattered out of the transparent scattering film; the near-eye display device further includes: and the shading element covers the surface of the reflection type volume holographic element back to the waveguide sheet.

19. An eyeglass, comprising: the near-eye display device of any one of claims 1-18.