CN218240562U - Optical system and near-to-eye display equipment - Google Patents

Abstract

The utility model provides an optical system and near-to-eye display device, including reflective display element, lighting unit, polarization beam splitter prism, quarter wave plate, reflection unit, linear polarization piece and light modulation spare. The illumination unit, the linear polarizer, the polarization splitting prism and the light modulation part are sequentially arranged along a first optical axis, and the reflective display unit, the polarization splitting prism, the quarter-wave plate and the reflection unit are sequentially arranged along a second optical axis. The illumination light that the illumination unit sent is through the transmission of line polaroid, polarization beam splitting prism reflection to reflective display element, and reflective display element sends image light to polarization beam splitting prism, and image light passes through polarization beam splitting prism, quarter wave plate transmission, reflection unit reflection, passes through quarter wave plate transmission again, finally passes through polarization beam splitting prism reflection and light modulation spare transmission, and this optical system utilizes polarization beam splitting prism and reflection unit folding light path, reduces optical system's volume and weight.

Description

Optical system and near-to-eye display equipment

Technical Field

The embodiment of the utility model provides an relate to optics technical field, in particular to optical system and near-to-eye display device.

Background

In recent years, as near-eye display technology becomes mature and develops, various types of small wearable display devices begin to enter the visual field of consumers, and the near-eye display devices are applied in various scenes, and the development prospect is expected.

However, in the optical system of the existing near-eye display apparatus, the system is complicated, the entire volume is large, and the mass is heavy.

SUMMERY OF THE UTILITY MODEL

The embodiment of the utility model provides a main technical problem who solves provides an optical system and near-to-eye display device, has reduced the volume and the weight of whole system.

The utility model discloses a technical scheme that embodiment adopted is: provided is an optical system including: the display device comprises a reflective display unit, an illumination unit, a polarization beam splitter prism, a quarter wave plate, a reflection unit, a linear polarizer and a light modulation piece. The lighting unit the linear polarizer the polarization beam splitter prism with the light modulation piece sets up along first optical axis in proper order, reflective display element the polarization beam splitter prism quarter wave plate with the reflection unit sets up along the second optical axis in proper order. The lighting unit is used for providing lighting rays; the linear polarizer, the light modulation piece and the quarter-wave plate are all used for changing the polarization state of light; the polarization beam splitter prism is used for reflecting the illumination light rays transmitted by the linear polarizer to the reflective display unit; the reflective display unit is used for receiving the illumination light and sending image light with image information to the polarization beam splitter prism, and the polarization states of the illumination light and the image light are different; the polarization beam splitter prism is also used for transmitting the image light to the quarter-wave plate; the reflection unit is used for reflecting the image light rays transmitted by the quarter wave plate to the quarter wave plate; the polarization beam splitter prism is also used for reflecting the image light transmitted by the quarter-wave plate to the light modulation part after being reflected by the reflection unit.

In some embodiments, the first surface of the polarization splitting prism is attached to the linear polarizer, the second surface of the polarization splitting prism is attached to the first surface of the quarter-wave plate, the third surface of the polarization splitting prism is attached to the light modulation member, the fourth surface of the polarization splitting prism is adjacent to the reflective display unit, and the second surface of the quarter-wave plate is attached to the transmission surface of the reflection unit.

In some embodiments, the polarization splitting prism includes a first triangular prism and a second triangular prism. The cross section of the first triangular prism and the cross section of the second triangular prism are both isosceles right triangles. The inclined plane of first prism with the inclined plane laminating of second prism forms the veneer face, the first right angle face subsides of second prism are located linear polarization piece, the first right angle face subsides of first prism are located the first face of quarter wave plate, the second right angle face subsides of first prism are located the finished piece is adjusted to light, the second right angle face of second prism is close to the reflective display unit sets up.

In some embodiments, the polarization splitting prism includes a first four-prism and a second four-prism. The cross section of the first quadrangular prism and the cross section of the second quadrangular prism are both quadrangular. The first surface of the first four-prism and the first surface of the second four-prism are attached to form an adhesive surface, the second surface of the first four-prism is attached to the linear polarizer, the second surface of the second four-prism is attached to the first surface of the quarter-wave plate, the third surface of the second four-prism is attached to the light modulation part, and the third surface of the first four-prism is adjacent to the reflective display unit; the fourth surface of the first quadrangular prism is connected to the first surface of the first quadrangular prism and the second surface of the first quadrangular prism, respectively, and the fourth surface of the second quadrangular prism is connected to the first surface of the second quadrangular prism and the third surface of the second quadrangular prism, respectively.

In some embodiments, the polarization splitting prism comprises a third four prism and a third three prism; the cross section of the third four-prism is quadrilateral, and the cross section of the third triangular prism is triangular; the first surface of the third quadrangular prism and the first surface of the third triangular prism are attached to form an adhesive surface, the second surface of the third quadrangular prism is attached to the linear polarizer, the second surface of the third triangular prism is attached to the first surface of the quarter wave plate, the third surface of the third triangular prism is attached to the light modulation part, and the third surface of the third quadrangular prism is arranged close to the display unit; and the fourth surface of the third four-prism is respectively connected with the first surface of the third four-prism and the second surface of the third four-prism, and the included angle between the third surface of the third four-prism and the third surface of the third triple prism is an obtuse angle.

In some embodiments, the lighting unit comprises a light source and a light homogenizing module. The light source, the dodging module, the linear polarizer, the polarization beam splitter prism and the light modulation part are arranged along the first optical axis in sequence.

In some embodiments, the light unifying module includes a condensing lens, a light diffusing element, and a light guiding element.

In some embodiments, the light directing element is a prismoid light directing element.

In some embodiments, the reflective display unit comprises LCOS.

In a second aspect, embodiments of the present invention provide a near-eye display device comprising an optical waveguide and an optical system as described in any one of the first aspects; the optical waveguide is configured to receive the image light transmitted through the light modulating member.

The utility model discloses embodiment's beneficial effect is: be different from prior art's condition, the embodiment of the utility model provides an optical system and near-to-eye display device, including reflective display element, lighting element, polarization beam splitter prism, quarter wave plate, reflection element, linear polarization piece and light modulation spare. The lighting unit, the linear polarizer, the polarization splitting prism and the light modulation part are sequentially arranged along a first optical axis, and the reflective display unit, the polarization splitting prism, the quarter wave plate and the reflection unit are sequentially arranged along a second optical axis. The illumination light that the illumination unit sent is reflected to reflective display element by polarization beam splitter prism after the transmission of warp polaroid, reflective display element receives illumination light after, sends image light to polarization beam splitter prism, this image light is after polarization beam splitter prism and quarter wave plate transmission, reflect through the reflection unit, again through quarter wave plate transmission, finally reflect through polarization beam splitter prism and light modulation spare and transmit away, this optical system utilizes polarization beam splitter prism and reflection element folding light path, reduce optical system's volume and weight when guaranteeing the light-emitting quality.

Drawings

One or more embodiments are illustrated by the accompanying figures in the drawings that correspond thereto and are not to be construed as limiting the embodiments, wherein elements/modules and steps having the same reference numerals are represented by like elements/modules and steps, unless otherwise specified, and the drawings are not to scale.

Fig. 1 is a structural diagram of an optical system provided by an embodiment of the present invention;

FIG. 2 is a schematic diagram of the optical path of FIG. 1;

fig. 3 is a schematic structural diagram of another optical system provided in the embodiment of the present invention;

FIG. 4 is a schematic diagram of the optical path of FIG. 3;

fig. 5 is a schematic structural diagram of another optical system provided by an embodiment of the present invention;

FIG. 6 is a schematic diagram of the optical path of FIG. 5;

FIG. 7 is a schematic view of an image of FIG. 3;

FIG. 8 is a schematic view of an image of FIG. 5;

fig. 9 is a schematic structural diagram of another optical system provided in the embodiment of the present invention;

FIG. 10 is a schematic illustration of the optical path of FIG. 9;

fig. 11 is a schematic structural diagram of an optical waveguide according to an embodiment of the present invention.

Description of reference numerals: 10. a reflective display unit; 20. a lighting unit; 21. a light source; 22. a light uniformizing module; 221. a light pipe; 222. a diffusion sheet; 223. a first Fresnel lens; 224. a second Fresnel lens; 30. a polarization splitting prism; 31. a first triangular prism; 32. a second triangular prism; 33. a first four-prism; 34. a second four-prism; 35. a third prism; 36. a third four-prism; 40. a quarter wave plate; 50. a reflection unit; 61. a linear polarizer; 62. a light modulating member; l1, lighting rays; l2, image light; s1, a first right-angle surface of a first triangular prism; s2, a second right-angle surface of the first triangular prism; s3, an inclined plane of the first triangular prism; s4, the inclined plane of the second triangular prism; s5, a first right-angle surface of a second triangular prism; s6, a second right-angle surface of the second triangular prism; x1, a first surface of a first four-prism; x2, a second surface of the first four-prism; x3, a third face of the first quad-prism; x4, a fourth face of the first quad prism; x5, a first surface of a second four-prism; x6, a second face of a second four-prism; x7, a third face of a second quad prism; x8, a fourth face of the second tetraprism; p1, a first surface of a third four-prism; p2, a second surface of a third four-prism;

p3, a third face of a third quad prism; p4, a fourth face of the third quadrangular prism; p5, a first face of a third prism; p6, a second face of the third triangular prism; p7, the third face of the third triangular prism.

Detailed Description

The present invention will be described in detail with reference to the following embodiments. The following examples will assist those skilled in the art in further understanding the present invention, but are not intended to limit the invention in any way. It should be noted that various changes and modifications can be made by one skilled in the art without departing from the spirit of the invention. All of which belong to the protection scope of the present invention.

To facilitate an understanding of the present application, the present application is described in more detail below with reference to the figures and the detailed description. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in the description of the present application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

It should be noted that, if not conflicting, various features of the embodiments of the present invention may be combined with each other and all are within the scope of protection of the present application. In addition, although the functional blocks are divided in the device diagram, in some cases, the blocks may be divided differently from those in the device. Further, the terms "first," "second," and the like, as used herein, do not limit the data and the execution order, but merely distinguish the same items or similar items having substantially the same functions and actions.

In a first aspect, an embodiment of the present invention provides an optical system, please refer to fig. 1, which includes: a reflective display unit 10, an illumination unit 20, a polarization splitting prism 30, a quarter wave plate 40, a reflection unit 50, a linear polarizer 61, and a light modulation element 62.

The illumination unit 20, the linear polarizer 61, the polarization splitting prism 30, and the light modulation member 62 are sequentially disposed along a first optical axis, and the reflective display unit 10, the polarization splitting prism 30, the quarter wave plate 40, and the reflection unit 50 are sequentially disposed along a second optical axis.

Referring to fig. 2, the illumination unit 20 is used for providing illumination light L1. Both the linear polarizer 61 and the quarter-wave plate 40 serve to change the polarization state of the light. The polarization splitting prism 30 serves to reflect the illumination light L1 transmitted through the linear polarizer 61 to the reflective display unit 10. The light modulation element 62 is used to modulate the image light to be emitted. The reflective display unit 10 is configured to receive the illumination light L1 and emit an image light L2 with image information to the polarization beam splitter prism 30, where the polarization states of the illumination light L1 and the image light L2 are different. The polarization splitting prism 30 also serves to transmit the image light L2 to the quarter wave plate 40. The reflection unit 50 is used for reflecting the image light L2 transmitted through the quarter wave plate 40 to the quarter wave plate 40. The polarization splitting prism 30 is further configured to reflect the image light L2 reflected by the reflection unit 50 and transmitted through the quarter-wave plate 40 to the light modulation element 62.

Specifically, the reflective display unit 10 in this embodiment is a spatial light modulator, which can receive the illumination light L1 and then emit the image light L2 with image information, and change the polarization state of the light, so that the polarization states of the illumination light L1 and the image light L2 are different. For example, the reflective display unit 10 can emit the image light L2 with the second polarization state after receiving the illumination light L1 with the first polarization state. The reflective display unit 10 may comprise an LCOS or other spatial light modulator.

The polarization splitting prism 30 has a polarization splitting surface having polarization splitting characteristics, and is used for reflecting the light of the first polarization state and transmitting the light of the second polarization state. The linear polarizer 61 is capable of converting light to a first polarization state. The first optical axis and the second optical axis are not parallel to each other, e.g. the first optical axis and the second optical axis may be perpendicular to each other. In the following description, the S polarization state is used as the first polarization state, and the P polarization state is used as the second polarization state, and in practical applications, the first polarization state may be the P polarization state, and the second polarization state may be the S polarization state.

The light modulation element 62 is a device having a beam-altering effect, and may be a linear polarizer disposed perpendicular to the optical axis, the linear polarizer being capable of converting image light into a first polarization state, or may be a 1/4 polarizer disposed at 45 ° to the optical axis, and may be a 1/2 polarizer disposed at 45 ° to the optical axis for producing circularly polarized light, or may be a 1/2 polarizer disposed at 45 ° to the optical axis for producing polarized light perpendicular to the original polarization state. The optical modulator can be a polarizing plate, an optical rotator, a compensating plate, a diffraction element and a coating element which rotate at any angle so as to meet the modulation function of the output image light.

In the optical system, referring to fig. 2, an illumination light L1 emitted by the illumination unit 20 passes through the linear polarizer 61 and is converted into an illumination light L1 in the S-polarization state, and the illumination light L1 in the S-polarization state is reflected to the reflective display unit 10 by the polarization splitting surface of the polarization splitting prism 30; the reflective display unit 10 receives the S-polarized illumination light L1, modulates the S-polarized illumination light L1, and emits P-polarized image light L2 to the polarization beam splitter prism 30, and then the P-polarized image light L2 is transmitted to the reflective unit 50 through the polarization beam splitter prism 30 and the quarter-wave plate 40; the reflection unit 50 reflects the image light L2, and the image light L2 is transmitted to the polarization beam splitter prism 30 through the quarter-wave plate 40 again; at this time, since the image light L2 passes through the quarter-wave plate 40 twice, the polarization state of the image light L2 is first converted from the P-polarization state to the circular polarization state, and then is converted from the circular polarization state to the S-polarization state, so that the image light L2 in the S-polarization state is reflected to the optical modulation element 62 by the polarization splitting prism 30 and is transmitted through the optical modulation element 62.

In the above embodiment, in the optical system, the imaging structure is formed by one reflection unit 50 and the polarization splitting prism 30, and the illumination unit 20 is used as an illumination structure, so that the volume and the weight of the whole optical system are reduced, the complexity of the whole optical system is reduced, and the light design of the near-eye display device is facilitated.

In some embodiments, the light modulation element 62 is a linear polarizer, and the polarization directions of the light modulation element 62 and the linear polarizer 61 are the same, so that stray light can be filtered out, and the image display quality can be improved.

In some embodiments, referring to fig. 1, a first surface of the polarization splitting prism 30 is attached to the linear polarizer 61, a second surface of the polarization splitting prism 30 is attached to a first surface of the quarter-wave plate 40, a third surface of the polarization splitting prism 30 is attached to the light modulation member 62, a fourth surface of the polarization splitting prism 30 is disposed adjacent to the reflective display unit 10, and a second surface of the quarter-wave plate 40 is attached to the transmission surface of the reflective unit 50. Through the arrangement, the compactness of the optical system can be improved, and the volume of the optical system can be further reduced.

In one specific embodiment, the reflection unit 50 includes a reflection lens having a transmission surface and a reflection surface, wherein the transmission surface of the reflection lens is bonded to the second surface of the quarter-wave plate. Specifically, the reflecting surface of the reflecting lens may be a spherical surface or an aspherical surface, and specific parameters of the spherical surface and the aspherical surface may be freely set according to actual conditions, which is not limited herein.

In some embodiments, referring to fig. 3, the illumination unit 20 includes a light source 21 and a light uniformizing module 22. The light source 21, the light uniformizing module 22, the linear polarizer 61, the polarization splitting prism 30, and the light modulation element 62 are sequentially disposed along the first optical axis. The light source 21 may be a three-color or four-color integrated LED, or other devices capable of emitting the illumination light L1. The dodging module 22 is used for collimating and dodging the illumination light L1. In this embodiment, the whole system is disposed along the first optical axis and is in a shape of a long strip, which is subsequently beneficial to disposing the optical system at the position of the temple.

In some of these embodiments, the light uniformizing module 22 includes a condenser lens, a light diffusing element, and a light guiding element. The light collecting lens can collect and collimate the light, the light diffusion element can improve the color uniformity and homogenize the light intensity and angle distribution of the light, and the light guide element can collect and homogenize the light. The condensing lens may include at least one of a cemented lens, a spherical lens, an aspherical lens, and a fresnel lens. The light diffusing element may include a micro-array lens, a diffuser sheet, or a diffuser sheet. The light guide element may comprise a light pipe, a light reflecting cup or a light guide rod. In one embodiment, the condensing lens is a fresnel lens and the light guide element is a prismoid-shaped light guide element. The frustum-shaped light guide element may be a frustum-shaped light guide tube (e.g., a frustum-shaped prism). The side of the frustum pyramid light guide element is inclined, namely the frustum pyramid light guide element has taper, and the divergence angle of the illumination light emitted by the light source can be adjusted, so that the divergence angle of the illumination light is reduced, and the collimation effect of the illumination light finally entering the polarization splitting prism is facilitated.

In one embodiment, referring to fig. 3, the light guide element is a truncated-pyramid-shaped light guide 221, the light diffusing element is a diffusion sheet 222, and the light condensing lenses are a first fresnel lens 223 and a second fresnel lens 224, so that the illumination light L1 emitted from the light source 21 can be collected and homogenized by the truncated-pyramid-shaped light guide 221, reduce the angle of the divergence angle, further homogenize the light intensity angular distribution by the diffusion sheet 222, and then be collected and collimated by the first fresnel lens 223 and the second fresnel lens 224. In practical applications, the light homogenizing module can be disposed according to actual requirements, and the limitation in the embodiment is not required.

The structure of the polarization splitting prism provided by the present invention is described in detail with reference to specific embodiments.

In one embodiment, referring to fig. 3, the polarization splitting prism 30 includes a first triangular prism 31 and a second triangular prism 32. The cross section of the first triangular prism 31 and the cross section of the second triangular prism 32 are both isosceles right triangles. The inclined plane S3 of first triple prism 31 and the inclined plane S4 laminating of second triple prism 32 form the cemented surface, and the first right-angle face S5 subsides of second triple prism 32 are located linear polarizer 61, and the first right-angle face S1 subsides of first triple prism 31 are located the first face of quarter wave plate 40, and the second right-angle face S2 subsides of first triple prism 31 are located light modulation spare 62, and the second right-angle face S6 of second triple prism 32 is close to reflective display element 10 and sets up.

In the polarization splitting prism 30, a film may be coated or a wire grid may be disposed on the bonding surface to make it have polarization splitting characteristics, and it may be used to reflect light in the first polarization state and transmit light in the second polarization state, or may be used to reflect light in the second polarization state and transmit light in the first polarization state, and may be specifically implemented according to a design of the polarization splitting film or the wire grid.

In the embodiment shown in fig. 3, referring to fig. 4, the illumination light L1 emitted from the light source 21 is collimated and homogenized by the light guide 221, the diffusion sheet 222, the first fresnel lens 223 and the second fresnel lens 224, and then is converted into the illumination light L1 in S-polarization state by the linear polarizer 61; then, after the illumination light L1 in the S polarization state enters the second prism 32, the illumination light L is reflected by the bonding surface and transmitted to the surface of the LCOS through the second prism 32, after the LCOS modulates the light, the light polarization state is converted into the P polarization state, and the LCOS reflects the image light L2 with the image information to the second prism 32; then, the image light L2 in the P polarization state is transmitted to the reflective lens through the adhesive surface, the first triple prism 31, and the quarter wave plate 40, and at this time, the image light L2 passes through the quarter wave plate 40 and then is converted from the P polarization state to the circular polarization state; then, the image light L2 is reflected by the reflection surface of the reflection lens, and then transmitted to the bonding surface through the quarter-wave plate 40 and the first triple prism 31, and at this time, the image light L2 passes through the quarter-wave plate 40 again and is converted from the circular polarization state to the S polarization state; finally, the S-polarization image light L2 is reflected to the light modulation element 62 through the adhesive surface and is transmitted by the light modulation element 62.

It can be seen that, in the optical system, the light is folded by the first triangular prism 31, the second triangular prism 32 and the reflecting lens, so that the overall volume of the system can be reduced; and the curvature of the reflecting surface of the reflecting lens can be used for shaping the light rays, so that the number of optical elements is effectively reduced, and the volume and the weight of the optical system are reduced.

In order to improve the display quality of the optical system, in another embodiment, referring to fig. 5, the polarization splitting prism 30 includes a first quadrangular prism 33 and a second quadrangular prism 34. The cross-section of the first quadrangular prism 33 and the cross-section of the second quadrangular prism 34 are quadrangular. The first surface X1 of the first four-prism 33 and the first surface X5 of the second four-prism 34 are attached to form an adhesive surface, the second surface X2 of the first four-prism 33 is attached to the linear polarizer 61, the second surface X6 of the second four-prism 34 is attached to the first surface of the quarter-wave plate 40, the third surface X7 of the second four-prism 34 is attached to the optical modulation member 62, and the third surface X3 of the first four-prism 33 is disposed adjacent to the reflective display unit 10. The fourth surface X4 of the first fourth prism 33 is in contact with the first surface X1 of the first fourth prism 33 and the second surface X2 of the first fourth prism 33, respectively, and the fourth surface X8 of the second fourth prism 34 is in contact with the first surface X5 of the second fourth prism 34 and the third surface X7 of the second fourth prism 34, respectively.

In the polarization splitting prism 30, a film may be coated or a wire grid may be disposed on the bonding surface to provide polarization splitting characteristics, which may be used to reflect light of a first polarization state and transmit light of a second polarization state. Specifically, referring to fig. 5, the cross section of the first fourth prism 33 and the cross section of the second fourth prism 34 are both right trapezoid, the fourth surface X4 of the first fourth prism 33 is parallel to the fourth surface X4 of the first fourth prism 33, an included angle between the second surface X2 of the first fourth prism 33 and the third surface X3 of the first fourth prism 33 is a right angle, the fourth surface X8 of the second fourth prism 34 is parallel to the second surface X6 of the second fourth prism 34, and an included angle between the third surface X7 of the second fourth prism 34 and the second surface X6 of the second fourth prism 34 is a right angle.

In the embodiment shown in fig. 5, referring to fig. 6, the illumination light L1 emitted from the light source 21 is collimated and homogenized by the light guide 221, the diffusion sheet 222, the first fresnel lens 223 and the second fresnel lens 224, and then converted into the illumination light L1 in the S-polarization state by the linear polarizer 61; then, after the illumination light L1 in the S polarization state enters the first four-prism 33, the illumination light L is reflected by the bonding surface and transmitted to the surface of the LCOS through the first four-prism 33, after the LCOS modulates the light, the light polarization state is converted into the P polarization state, and the LCOS reflects the image light L2 with the image information to the first four-prism 33; then, the image light L2 in the P polarization state is transmitted to the reflective lens through the adhesive surface, the second four-prism 34, and the quarter-wave plate 40, and at this time, the image light L2 passes through the quarter-wave plate 40 and then is converted from the P polarization state to the circular polarization state; then, the image light L2 is reflected by the reflection surface of the reflection lens, and then transmitted to the bonding surface through the quarter-wave plate 40 and the second four-prism 34, and at this time, the image light L2 passes through the quarter-wave plate 40 again and is converted from the circular polarization state to the S polarization state; finally, the S-polarization image light L2 is reflected to the light modulation element 62 through the adhesive surface and is transmitted by the light modulation element 62.

Similarly, in the optical system, the light is folded through the first and second quadrangular prisms 32 and 34 and the reflection lens, so that the light path can be folded, the complexity of the system can be reduced, and the light can be shaped by using the curvature of the reflection surface of the reflection lens, so that the number of optical elements can be effectively reduced, and the volume and the weight of the optical system can be reduced.

In addition, the present embodiment can also improve the display quality of an image as compared with the embodiment shown in fig. 3. Referring to fig. 7, it can be seen from fig. 7 that symmetric stray light may exist when the vertical field angle is ± 45 °, and through ray tracing analysis, in the embodiment shown in fig. 3, since the illumination light incident on the reflective display unit 10 not only irradiates the image output position but also irradiates the components around the image output position, the light is reflected by the components around the image output position and enters the prism, and is totally reflected on the second right-angle surface S2 of the first triangular prism 31 and the first right-angle surface S5 of the second triangular prism 32, thereby causing stray light to appear during image display. In this embodiment, by providing the first fourth prism 33 and the second fourth prism 34, the light reflected by the components around the image output position and the light totally reflected by the second surface X2 of the first fourth prism 33 and the third surface X7 of the second fourth prism 34 can be transmitted by the fourth surface X4 of the first fourth prism 33 and the fourth surface X8 of the second fourth prism 34, so as to prevent the light from entering the subsequent optical device, reduce the light entering the subsequent optical path after the light totally reflected by the second surface X2 of the first fourth prism 33 and the third surface X7 of the second fourth prism 34, and improve the image display quality, and as can be seen from fig. 8, there is no symmetric stray light when the vertical field angle is ± 45 ° in the image display process in this embodiment, and it is verified that the structure provided in this embodiment can improve the image display quality.

In still another embodiment, referring to fig. 9, the polarization splitting prism 30 includes a fourth prism 36 and a third prism 35. The cross section of the third four prism 36 is a quadrangle, and the cross section of the third three prism 35 is a triangle. A first surface P1 of the third quadrangular prism 36 and a first surface P5 of the third triangular prism 35 are attached to form a gluing surface, a second surface P2 of the third quadrangular prism 36 is attached to the linear polarizer 61, a second surface P6 of the third triangular prism 35 is attached to the first surface of the quarter wave plate 40, a third surface P7 of the third triangular prism 35 is attached to the optical modulation part 62, and a third surface P3 of the third quadrangular prism 36 is arranged adjacent to the display unit 10; the fourth surface P4 of the third four-prism 36 is connected to the first surface P1 of the third four-prism 36 and the second surface P2 of the third four-prism 36, respectively, and the included angle between the third surface P3 of the third four-prism 36 and the third surface P7 of the third three-prism 35 is an obtuse angle.

In the polarization splitting prism 30, a film may be coated or a wire grid may be disposed on the bonding surface to provide polarization splitting characteristics, which may be used to reflect light of a first polarization state and transmit light of a second polarization state. Specifically, in this optical system, third face P7 of third triangular prism 35 and second face P6 of third triangular prism 35 are not perpendicular, and third face P7 of third triangular prism 35 and third face P3 of third rectangular prism 36 are not perpendicular. The cross section of the third four-prism 36 is a right trapezoid, the third face P3 of the third four-prism 36 is parallel to the fourth face P4 of the third four-prism 36, and the included angle between the third face P3 of the third four-prism 36 and the second face P2 of the third four-prism 36 is a right angle.

In the embodiment shown in fig. 9, referring to fig. 10, the illumination light L1 emitted from the light source 21 is collimated and homogenized by the light guide 221, the diffusion sheet 222, the first fresnel lens 223 and the second fresnel lens 224, and then converted into the illumination light L1 in the S-polarization state by the linear polarizer 61; then, after entering the third four-prism 36, the illumination light L1 in the S-polarization state is reflected by the bonding surface and transmitted to the surface of the LCOS through the third four-prism 36, after the LCOS modulates light, the polarization state of the light is converted into the P-polarization state, and the LCOS reflects the image light L2 with image information to the third four-prism 36; then, the image light L2 in the P polarization state is transmitted to the reflective lens through the adhesive surface, the third triple prism 35, and the quarter wave plate 40, and at this time, the image light L2 passes through the quarter wave plate 40 and then is converted from the P polarization state to the circular polarization state; then, the image light L2 is reflected by the reflection surface of the reflection lens, and then transmitted to the bonding surface through the quarter-wave plate 40 and the third triple prism 35, and at this time, the image light L2 passes through the quarter-wave plate 40 again, and is converted from the circular polarization state to the S polarization state; finally, the S-polarization image light L2 is reflected to the light modulation element 62 through the adhesive surface and is transmitted by the light modulation element 62.

Similarly, in the optical system, the light can be folded through the third triple prism 35, the third quadruple prism 36 and the reflection lens, the complexity of the system is reduced, and the light can be shaped by using the curvature of the reflection surface of the reflection lens, so that the number of optical elements is effectively reduced, and the volume and the weight of the optical system are reduced.

In addition, the present embodiment can also improve the display quality of an image as compared with the embodiment shown in fig. 3. In this embodiment, the third face P7 of the third triangular prism 35 is not perpendicular to the second face P6 of the third triangular prism 35, and the third face P7 of the third triangular prism 35 is not perpendicular to the third face P3 of the third fourth prism 36, so that the light of the stray light cannot be totally reflected on the third face P7 of the third triangular prism 35; in addition, the fourth surface P4 of the third four-prism 36 can transmit the light totally reflected by the fourth surface P4 of the third four-prism 36, so that the light is prevented from entering a subsequent optical device, the light entering a subsequent optical path after totally reflecting by the second surface P2 of the third four-prism 36 is reduced, and the image display quality is improved. In summary, the structure provided by the embodiment can improve the display quality of the image.

Further, the third triangular prism 35 may be used to couple image light into the waveguide substrate. For example, by design, an included angle between the third face P7 of the third triangular prism 35 and the first face P5 of the third triangular prism 35 satisfies the design of the coupling-in prism in the geometric optical waveguide, and then the optical system is applied to the near-eye display device, so that the third triangular prism 35 can directly serve as the coupling-in region of the waveguide substrate without the coupling-in region, and the waveguide substrate without the coupling-in region is used as the near-eye display device, so that the coupling-in prism does not need to be additionally arranged in the near-eye display device, the number of optical elements is effectively reduced, and the volume and the weight of the system are further reduced.

In a second aspect, embodiments of the present invention provide a near-eye display device comprising an optical waveguide and an optical system as in any one of the embodiments of the first aspect; the optical waveguide is for receiving the image light transmitted through the light modulating member. The optical waveguide may be a geometric array optical waveguide or a grating optical waveguide. In this embodiment, the optical system has the structure and function as described in any one of the embodiments of the first aspect, and details are not repeated herein.

In some embodiments, the optical waveguide comprises a waveguide substrate, an incoupling region and an outcoupling region, or the optical waveguide comprises a waveguide substrate, an incoupling region, a turning region and an outcoupling region. In the near-eye display device, the coupling-in region of the optical waveguide is disposed adjacent to the light modulating member. In one embodiment, a coupling prism is further disposed between the coupling-in region of the optical waveguide and the light modulation element, and the coupling prism is used for adjusting an incident angle of the image light entering the optical waveguide. Thus, after being transmitted by the light modulation part, the image light can be coupled into the waveguide substrate through the coupling-in prism and the coupling-in area, and then is totally reflected and propagated to the coupling-out area in the waveguide substrate and is coupled out to human eyes through the coupling-out area, or after being transmitted by the light modulation part, the image light can be coupled into the waveguide substrate through the coupling-in area, and then is totally reflected and propagated to the turning area in the waveguide substrate, and then is expanded and propagated to the coupling-out area through the turning area, and finally is coupled out to human eyes through the coupling-out area. In another embodiment, no coupling-in prism may be provided between the coupling-in region of the light guide and the light modulating element. Specifically, in the near-eye display device, referring to fig. 11, the light guide 70 is disposed adjacent to the light modulation member 62, and the polarization splitting prism 30 includes a third quadrangular prism 36 and a third triangular prism 35, wherein the third triangular prism 35 is further configured to couple the image light L2 into the interior of the waveguide substrate. In the near-eye display device, by using the third and fourth prisms 36 as the coupling-in prism, the coupling-in prism can be omitted, and the overall volume and weight can be reduced compared to the previous embodiment. If the optical waveguide is a diffractive light waveguide, the near-eye display device may employ the optical system of any of the embodiments described above, and a coupling-in prism may or may not be provided between the coupling-in region of the optical waveguide and the light modulation element.

It should be noted that the above-described device embodiments are merely illustrative, where the units described as separate parts may or may not be physically separate, and the parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit it; within the idea of the invention, also technical features in the above embodiments or in different embodiments can be combined, steps can be implemented in any order, and there are many other variations of the different aspects of the invention as described above, which are not provided in detail for the sake of brevity; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art will understand that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; such modifications or substitutions do not depart from the scope of the invention in its corresponding aspects.

Claims (10)

1. An optical system, comprising: the device comprises a reflective display unit, a lighting unit, a polarization beam splitter prism, a quarter wave plate, a reflection unit, a linear polarizer and a light modulation piece;

the illumination unit, the linear polarizer, the polarization splitting prism and the light modulation piece are sequentially arranged along a first optical axis, and the reflective display unit, the polarization splitting prism, the quarter wave plate and the reflection unit are sequentially arranged along a second optical axis;

the lighting unit is used for providing lighting rays; the linear polarizer, the light modulation piece and the quarter-wave plate are all used for changing the polarization state of light; the polarization beam splitter prism is used for reflecting the illumination light rays transmitted by the linear polarizer to the reflective display unit; the reflective display unit is used for receiving the illumination light and sending image light with image information to the polarization beam splitter prism, and the polarization states of the illumination light and the image light are different; the polarization beam splitter prism is also used for transmitting the image light to the quarter-wave plate; the reflection unit is used for reflecting the image light rays transmitted by the quarter-wave plate to the quarter-wave plate; the polarization beam splitter prism is also used for reflecting the image light transmitted by the quarter-wave plate to the light modulation part after being reflected by the reflection unit.

2. The optical system of claim 1, wherein the first surface of the polarization beam splitter is attached to the linear polarizer, the second surface of the polarization beam splitter is attached to the first surface of the quarter-wave plate, the third surface of the polarization beam splitter is attached to the optical modulation element, the fourth surface of the polarization beam splitter is disposed adjacent to the reflective display unit, and the second surface of the quarter-wave plate is attached to the transmissive surface of the reflective display unit.

3. The optical system of claim 2, wherein the polarization splitting prism comprises a first triangular prism and a second triangular prism;

the cross section of the first triangular prism and the cross section of the second triangular prism are both isosceles right triangles;

the inclined plane of first prism with the inclined plane laminating of second prism forms the veneer face, the first right angle face subsides of second prism are located linear polarization piece, the first right angle face subsides of first prism are located the first face of quarter wave plate, the second right angle face subsides of first prism are located the finished piece is adjusted to light, the second right angle face of second prism is close to the reflective display unit sets up.

4. The optical system of claim 2, wherein the polarization splitting prism comprises a first quad prism and a second quad prism;

the cross section of the first quadrangular prism and the cross section of the second quadrangular prism are both quadrangles;

the first surface of the first four-prism and the first surface of the second four-prism are attached to form an adhesive surface, the second surface of the first four-prism is attached to the linear polarizer, the second surface of the second four-prism is attached to the first surface of the quarter-wave plate, the third surface of the second four-prism is attached to the light modulation part, and the third surface of the first four-prism is adjacent to the reflective display unit;

the fourth surface of the first four-prism is respectively connected with the first surface of the first four-prism and the second surface of the first four-prism, and the fourth surface of the second four-prism is respectively connected with the first surface of the second four-prism and the third surface of the second four-prism.

5. The optical system of claim 2, wherein the polarization splitting prism comprises a third four prism and a third three prism;

the cross section of the third four-prism is quadrilateral, and the cross section of the third triangular prism is triangular;

the first surface of the third quadrangular prism and the first surface of the third triangular prism are attached to form an adhesive surface, the second surface of the third quadrangular prism is attached to the linear polarizer, the second surface of the third triangular prism is attached to the first surface of the quarter wave plate, the third surface of the third triangular prism is attached to the light modulation part, and the third surface of the third quadrangular prism is arranged close to the display unit;

and the fourth surface of the third four-prism is respectively connected with the first surface of the third four-prism and the second surface of the third four-prism, and the included angle between the third surface of the third four-prism and the third surface of the third triple prism is an obtuse angle.

6. The optical system according to any one of claims 1 to 5, wherein the illumination unit comprises a light source and a light homogenizing module;

the light source, the dodging module, the linear polarizer, the polarization beam splitter prism and the light modulation part are arranged along the first optical axis in sequence.

7. The optical system of claim 6, wherein the dodging module comprises a condensing lens, a light diffusing element, and a light guiding element.

8. The optical system of claim 7, wherein the light directing element is a prismoid light directing element.

9. The optical system according to any of claims 1-5, wherein the reflective display unit comprises LCOS.

10. A near-eye display device comprising an optical waveguide, and an optical system according to any one of claims 1 to 9;

the optical waveguide is configured to receive the image light transmitted through the light modulation element.

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