CN116804814A

CN116804814A - Projection display device, optical system and manufacturing method thereof

Info

Publication number: CN116804814A
Application number: CN202210258125.9A
Authority: CN
Inventors: 郎海涛; 景桂芬; 徐亚辉; 王志超; 袁迪; 张鹤腾; 顾菲
Original assignee: Ningbo Sunny Automotive Optech Co Ltd
Current assignee: Ningbo Sunny Automotive Optech Co Ltd
Priority date: 2022-03-16
Filing date: 2022-03-16
Publication date: 2023-09-26

Abstract

The application provides a projection display device, an optical system and a manufacturing method thereof. The projection display device comprises a polarization splitting element, at least one image generating element and an optical compensation element. Wherein the polarization splitting element is configured to polarize an incident light beam incident to the polarization splitting element into at least two outgoing light beams of different directions. The image generating element is located on a propagation path of at least one outgoing light beam, and is configured to modulate the outgoing light beam into information light based on image information. The optical compensation element is positioned between the polarization splitting element and the image generating element, and at least part of the emergent beam and the information light pass through the optical compensation element. In this way, by arranging the optical compensation element for allowing at least part of the outgoing light beam and the information light to pass through, multi-screen display at different projection distances can be realized, and the multi-screen display device has a simple structure and low cost. In addition, by arranging the optical compensation element, dark stray light can be reduced, and the overall contrast of the bright and dark areas of the projection display device is improved.

Description

Projection display device, optical system and manufacturing method thereof

Technical Field

The present application relates to the field of display technology, and more particularly, to a projection display device, an optical system, and a method of manufacturing the same.

Background

With the development of 3D Display technology, the application of the 3D Display technology in the automotive field is also becoming more and more widespread, such as vehicle Head Up Display (HUD for short).

Currently, the Liquid Crystal On Silicon (LCOS) technology (Liquid Crystal On Silicon, abbreviated as LCOS) has advantages of high light utilization, smooth pixels, natural images, and the like, and is commonly used in AR HUDs. LCOS imaging effect is better than dot matrix liquid crystal display technology (Liquid Crystal Display, LCD for short), and the technical monopoly problem of DMD chip in digital light processing (Digital Light Processing, DLP for short) scheme can be broken simultaneously, realizing autonomous and controllable technology. But also has the following problems:

1. at present, the vehicle-mounted HUD needs a complex multi-system structure to realize the effect of multi-screen image surfaces under different projection distances, and has the advantages of larger volume and higher cost;

2. under the condition of the dark state of LCOS, the S light incident on the LCOS chip is not changed in polarization state after LCOS modulation, and is still S polarized light, but phase deviation occurs, so that the S light is impure in polarization state, and part of light can enter into the dark state stray light on the image surface through the PBS prism;

3. the contrast of the whole machine is lower due to the influence of stray light.

Disclosure of Invention

The present application provides a projection display device, an optical system, and a method of manufacturing the same that at least partially solve the above-described problems of the related art.

In one aspect, the present application provides a projection display device including a polarizing beam splitting element, at least one image generating element, and an optical compensation element. Wherein the polarization splitting element is configured to polarize an incident light beam incident to the polarization splitting element into at least two outgoing light beams of different directions. The image generating element is located on a propagation path of at least one outgoing light beam, and is configured to modulate the outgoing light beam into information light based on image information. The optical compensation element is positioned between the polarization splitting element and the image generating element, and at least part of the emergent beam and the information light pass through the optical compensation element.

In some embodiments, the projection of the optical compensation element in the direction of the outgoing light beam covers at least part of the image generating element.

In some embodiments, the projection of the optical compensation element in the direction of the outgoing light beam does not exceed one half of the image generating element.

In some embodiments, the thickness of the optical compensation element is less than or equal to 2mm.

In some embodiments, the optical compensation element has a plurality of different thickness dimensions in the direction of the outgoing light beam.

In some embodiments, the side of the optical compensation element facing the polarizing beam splitter element is a stepped surface and the side of the optical compensation element facing the image generating element is a planar surface.

In some embodiments, the maximum thickness of the optical compensation element is less than or equal to 2mm.

In some embodiments, the optical compensation element has a wavelength of 400nm or greater and 700nm or less; and the refractive index of the optical compensation element is more than or equal to 1.4 and less than or equal to 1.8.

In some embodiments, the fast axis rotation angle of the optical compensation element is equal to or greater than-20 ° and equal to or less than 20 °.

In some embodiments, the image-generating element is a reflective liquid crystal display chip.

In some embodiments, the projection display device further comprises: and the light source assembly is arranged on the incident light path of the polarization beam splitting element and forms an incident light beam.

In some embodiments, the light source assembly is an LD light source system or an LED light source system.

Another aspect of the present application provides an optical system including the projection display device as above and an imaging lens configured to project information light carrying image information output from the projection display device onto at least two imaging surfaces.

In some embodiments, the distance between the at least two imaging surfaces ranges from 20mm or more to 50mm or less.

In some embodiments, the ratio between the focal length value of the imaging lens and the thickness of the optical compensation element is greater than or equal to 10 and less than or equal to 100.

In some embodiments, the ratio between the lens length of the imaging lens and the focal length value of the imaging lens is 4.9 or less.

In some embodiments, the ratio between the optical back focal length of the imaging lens and the lens length of the imaging lens is greater than or equal to 0.3.

Another aspect of the present application provides a method of manufacturing an optical system, including: arranging a polarization splitting element in the propagation direction of the incident light beam, the polarization splitting element being configured to polarize the incident light beam into at least two outgoing light beams of different directions; disposing at least one image generating element on a propagation path of the outgoing light beam, the image generating element being configured to modulate the outgoing light beam into information light based on the image information; disposing an optical compensation element between the polarization splitting element and the image generating element, the optical compensation element configured to pass at least a portion of the outgoing light beam and the information light; and disposing an imaging lens in a propagation direction of the information light, the imaging lens being configured to project the information light onto at least two imaging planes.

In some embodiments, disposing an optical compensation element between the polarization splitting element and the image generating element comprises: an optical compensation element, which projects in the direction of the outgoing light beam so as to cover at least a part of the image generation element, is provided between the polarization splitting element and the image generation element.

In some embodiments, disposing an optical compensation element between the polarization splitting element and the image generating element comprises: an optical compensation element having a plurality of different thickness dimensions in the direction of the outgoing light beam is disposed between the polarization splitting element and the image generating element.

In some embodiments, the side of the optical compensation element facing the polarizing beam splitting element is provided as a stepped surface; and a side of the optical compensation element facing the image generating element is provided as a plane.

In some embodiments, the method of manufacturing further comprises: the light source assembly is disposed on an incident light path of the polarization beam splitter, and is configured to emit an incident light beam.

In some embodiments, disposing a light source assembly on an incident light path of a polarizing beam splitter element includes: an LD light source system or an LED light source system is provided on the incident light path of the polarization beam splitter.

In the projection display device provided by at least one embodiment of the application, the optical compensation element which enables at least part of emergent light beams and information light to pass through is arranged, so that multi-screen display under different projection distances can be realized, the structure is simple, and the cost is low. In addition, by arranging the optical compensation element, dark stray light can be reduced, and the overall contrast of the bright and dark areas of the projection display device is improved.

Drawings

Other features, objects and advantages of the present application will become more apparent upon reading of the detailed description of non-limiting embodiments, made with reference to the following drawings. Wherein:

fig. 1 is a schematic configuration diagram of an optical system 100 according to a first embodiment of the present application;

fig. 2 is a schematic structural view of an optical system 200 according to a second embodiment of the present application;

fig. 3 is a schematic structural view of an optical system 300 according to a third embodiment of the present application; and

fig. 4 is a flow chart illustrating a method of manufacturing an optical system according to an embodiment of the present application.

Detailed Description

For a better understanding of the application, various aspects of the application will be described in more detail with reference to the accompanying drawings. It should be understood that the detailed description is merely illustrative of exemplary embodiments of the application and is not intended to limit the scope of the application in any way. Like reference numerals refer to like elements throughout the specification. The expression "and/or" includes any and all combinations of one or more of the associated listed items.

It should be noted that in this specification, the expressions first, second, third, etc. are used only to separate one feature from another feature region, and do not denote any limitation of features, particularly do not denote any order of precedence. Thus, a first portion discussed in this disclosure may also be referred to as a second portion, and vice versa, without departing from the teachings of the present disclosure.

In the drawings, the thickness, size, and shape of the components have been slightly adjusted for convenience of description. The figures are merely examples and are not drawn to scale. As used herein, the terms "about," "approximately," and the like are used as terms of a table approximation, not as terms of a table degree, and are intended to account for inherent deviations in measured or calculated values that will be recognized by one of ordinary skill in the art.

It will be further understood that terms such as "comprises," "comprising," "includes," "including," "having," "containing," "includes" and/or "including" are open-ended, rather than closed-ended, terms that specify the presence of the stated features, elements, and/or components, but do not preclude the presence or addition of one or more other features, elements, components, and/or groups thereof. Furthermore, when describing embodiments of the application, use of "may" means "one or more embodiments of the application. Also, the term "exemplary" is intended to refer to an example or illustration.

Unless otherwise defined, all terms (including engineering and technical terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present application pertains. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

It should be noted that, without conflict, the embodiments of the present application and features of the embodiments may be combined with each other. In addition, unless explicitly defined or contradicted by context, the particular steps included in the methods described herein need not be limited to the order described, but may be performed in any order or in parallel. The application will be described in detail below with reference to the drawings in connection with embodiments.

The embodiment of the application provides a projection display device, which comprises a polarization beam splitting element, at least one image generating element and an optical compensation element. Wherein the polarization splitting element is configured to polarize an incident light beam incident to the polarization splitting element into at least two outgoing light beams of different directions. The image generating element is located on a propagation path of at least one outgoing light beam, and is configured to modulate the outgoing light beam into information light based on image information. The optical compensation element is positioned between the polarization splitting element and the image generating element, and at least part of the emergent beam and the information light pass through the optical compensation element. In this way, by arranging the optical compensation element for allowing at least part of the outgoing light beam and the information light to pass through, multi-screen display at different projection distances can be realized, and the multi-screen display device has a simple structure and low cost. In addition, by arranging the optical compensation element, dark stray light can be reduced, and the overall contrast of the bright and dark areas of the projection display device is improved.

Fig. 1 shows a schematic configuration of an optical system 100 according to a first embodiment of the present application.

As shown in fig. 1, the optical system 100 includes a projection display device 110 and an imaging lens 150. The projection display device 110 includes a polarization beam splitter 111, an image generator 112, and an optical compensation element 113. The imaging lens 150 is configured to project light carrying the image information output from the projection display device 110 onto at least two imaging planes.

In some embodiments, the polarizing beam splitting element 111 is configured to polarize an incident light beam incident on the polarizing beam splitting element 111 into at least two outgoing light beams of different directions. The polarization splitting element 111 is illustratively a PBS prism. The image generating element 112 is located on the propagation path of at least one outgoing light beam, which is configured to modulate the outgoing light beam into information light based on image information. The optical compensation element 113 is located between the polarization beam splitter 111 and the image generation element 112, and the projection of the optical compensation element 113 in the direction of the outgoing light beam covers part of the image generation element 112, as shown with reference to fig. 1.

In detail, as shown in fig. 1, the incident light beam to the polarization beam splitter 111 includes P-polarized light and S-polarized light. The P polarized light comprises a large part of P light and a small amount of stray light, and the S polarized light comprises a large part of S light and a small amount of stray light. The polarization beam splitter 111 has a characteristic of transmitting P-polarized light and reflecting S-polarized light. Therefore, after the P-polarized light and the S-polarized light are simultaneously incident on the polarization beam splitter 111, the S-polarized light is reflected as an outgoing beam of the S-polarized light when passing through the polarization beam splitter 111.

The S-polarized light exit beam of the first portion enters the image generating element 112 after passing through the optical compensation element 113. The optical compensation element 113 can improve the purity of the portion of the S-polarized light, reduce parasitic light, and does not affect the polarization state of the P-polarized light. Alternatively, the image generating element 112 is a reflective image generating element 112. When the image generating element 112 is in a bright state, the S-polarized light of the first portion may be modulated into P-polarized light and reflected, and the reflected P-polarized light of the first portion may be incident on the polarization beam splitter 111 after passing through the optical compensation element 113. Since the optical compensation element 113 does not affect the polarization state of the P-polarized light, and the polarization beam splitter 111 has a property of transmitting the P-polarized light, the P-polarized light of the first portion is transmitted through the polarization beam splitter 111, then enters the imaging lens 150, and is projected onto the first imaging plane 151.

The second portion of the S polarized light outgoing beam does not pass through the optical compensation element 113, but directly enters the image generating element 112, the image generating element 112 modulates the S polarized light of the second portion into P polarized light and reflects the P polarized light, and the reflected P polarized light of the second portion passes through the polarization splitting element 111, is transmitted into the imaging lens 150, and is projected onto the second imaging plane 152.

In the above-described scheme, since only a part of the outgoing beam of the S-polarized light passes through the optical compensation element 113, the optical compensation element 113 reduces only the stray light in the part of the S-polarized light. Moreover, the material of the optical compensation element 113 has a corresponding refractive index, so that the P-polarized light carrying the image information reflected by the image generating element 112 can be displayed on the first imaging plane 151 and the second imaging plane 152 at different positions, forming a dual-screen system, which has a simple structure and low cost.

In addition, in the case where the image generating element 112 is in the dark state, the S-polarized light incident on the image generating element 112 does not change the polarization state, and the light modulated by the image generating element 112 is still the S-polarized light, but the angle is deflected, and a part of the light directly enters the imaging plane to form dark-state stray light. The optical compensation element 113 of the present application can shift the phase of the modulated S-polarized light in the dark state to inhibit the angular deviation of the polarization axis caused by the direction of the S-polarized light irradiated onto the polarization beam splitter 111, and can effectively improve the polarization purity of the S-polarized light in the dark state, so that the S-polarized light can be totally reflected as much as possible when passing through the polarization beam splitter 111, and the light is prevented from being transmitted to the imaging lens 150 to form dark-state stray light, thereby improving the contrast ratio of the whole optical system 100.

In some embodiments, the fast axis rotation angle θ of the optical compensation element 113 may be adjusted by rotating the optical compensation element 113. For example, the fast axis rotation angle θ of the optical compensation element 113 is adjusted between-20 ° and 20 ° to find the lowest value of the dark state, and the dark state S-polarized light has the highest purity, so that the phase shift of the S-polarized light modulated by the image generating element 112 in the dark state can be suppressed.

Illustratively, the optical compensation element 113 operates at a wavelength in the range of 400nm to 700nm, and the refractive index n of the optical compensation element 113 ranges from 1.4 or more to 1.8 or less. When the optical compensation element 113 is manufactured, a plurality of wave plates can be overlapped, the optical axes intersect each other at an angle, and different phase retardation effects can be achieved.

Further, P-polarized light in the incident light passes through the polarization beam splitter 111 in the incident direction when passing through the polarization beam splitter 111. Optionally, another image generating element (not shown) may be provided on the outgoing light path of the P-polarized light.

In some embodiments, the projection of the optical compensation element 113 in the direction of the outgoing light beam covers approximately one half of the image generating element 112.

In some embodiments, the thickness of the optical compensation element 113 is less than or equal to 2mm, so as to reduce the difficulty of adjusting the optical compensation element 113. For example, if the thickness of the optical compensation element 113 is too thick, this may result in an increase in the back focus of the imaging lens 150, and the pressure of the imaging lens 150 is large.

In some embodiments, the distance between the first imaging plane 151 and the second imaging plane 152 satisfies the following relationship:

where Δl is the distance between the first imaging plane 151 and the second imaging plane 152, Δl=l ₂ -L ₁ ，L ₂ L is the distance between the first imaging surface 151 and the imaging lens 150 ₁ L is the distance between the second imaging plane 152 and the imaging lens 150 ₁ It can also be understood that the distance L between the imaging surface closer to the imaging lens 150 and the imaging lens 150 ₂ It can also be understood that the distance between the imaging surface farther from the imaging lens 150 and the imaging lens 150 (refer to fig. 1), d is the thickness of the optical compensation element 113, n is the refractive index of the optical compensation element 113, and f' is the focal length value of the imaging lens 150.

In some embodiments, the ratio between the focal length f' of the imaging lens 150 and the thickness d of the optical compensation element 113 is greater than or equal to 10 and less than or equal to 100. Optionally, the imaging lens 150 is a combination of multiple lenses, and the focal length f' of the imaging lens 150 is the focal length of the whole set.

Illustratively, ΔL ranges from approximately 20mm or more to 50mm or less.

In the above scheme, controlling the distance between imaging surfaces and the thickness of the optical compensation element 113 can ensure the size of the whole machine and the full utilization of the optical compensation element 113. Moreover, when the optical system 100 of the present application is applied to a vehicle-mounted HUD, the overall size of the HUD is controlled, while ensuring the comfort of human eyes.

In some embodiments, the ratio between the lens length TL of the imaging lens 150 and the focal length f' of the imaging lens 150 is less than or equal to 4.9.

It can be understood that when the imaging lens 150 is a combination of a plurality of lenses, the lens length TL of the imaging lens 150 is the distance from the center of the front end face of the first lens to the center of the rear end face of the last lens.

In the scheme, the lens group is short in length and compact in structure, so that miniaturization of the imaging lens 150 is facilitated, the sensitivity of the lens is reduced, the production yield is improved, and the production cost is reduced.

In some embodiments, the ratio between the optical back focal length BFL of the imaging lens 150 and the lens length TL of the imaging lens 150 is greater than or equal to 0.3.

The optical back focal length BFL of the imaging lens 150 is the distance from the back end surface of the last lens of the imaging lens 150 to the imaging surface.

The technical scheme can realize miniaturization, and is beneficial to the assembly of lighting elements such as prisms and the like.

In some embodiments, image-generating element 112 is a reflective liquid crystal display chip (LCOS chip). The resolution of the LCOS chip is high, so that the definition is not affected even in the case of forming a dual-screen system.

In some embodiments, the projection display device 110 further includes a light source assembly 114, and the light source assembly 114 is disposed on an incident light path of the polarization beam splitter 111 and forms an incident light beam.

In some embodiments, the light source assembly 114 is an LD light source 1141 system. Optionally, the LD light source 1141 system includes an LD light source 1141, a beam expanding system 1142, a compound eye 1143, and a relay system 1144. The light beam emitted by the LD light source 1141 needs to be expanded by the beam expanding system 1142 and is uniformly transmitted by the compound eye 1143, and then the light beam is formed into an incident light beam (P polarized light and S polarized light) by the relay system 1144, and the incident light beam is incident on the polarization beam splitter 111.

Fig. 2 shows a schematic configuration of an optical system 200 according to a second embodiment of the present application.

As shown in fig. 2, the optical system 200 includes a projection display device 210 and an imaging lens 250. The projection display device 210 includes a polarization splitting element 211, an image generating element 212, and an optical compensation element 213. The imaging lens 250 is configured to project light carrying the image information output from the projection display device 210 to at least two imaging planes (a first imaging plane 251 and a second imaging plane 252).

In some embodiments, polarizing beam-splitting element 211 is configured to polarize an incident light beam incident on polarizing beam-splitting element 211 into at least two differently directed outgoing light beams. The image generating element 212 is located in the propagation path of at least one outgoing light beam, which is configured to modulate the outgoing light beam into information light based on image information. The optical compensation element 213 is located between the polarization beam splitting element 211 and the image generating element 212, and the projection of the optical compensation element 213 in the direction of the outgoing light beam covers at least part of the image generating element 212.

Unlike the first embodiment shown in fig. 1, the light source assembly 214 in this embodiment is an LED light source system. Optionally, as shown in fig. 2, the LED light source system includes an LED light source 2141, a collimating and beam combining system 2142, a compound eye 2143, and a relay system 2144. The divergent light beam emitted by the LED light source 2141 needs to be collimated by the collimating and beam-combining system 2142, and then is uniformly transmitted by the compound eye 2143, and then is transmitted by the relay system 2144 to form an incident light beam (P polarized light and S polarized light) to be incident on the polarization beam-splitting element 211.

In the case of no conflict, the other features of the present embodiment may refer to the features of the first embodiment shown in fig. 1, and the disclosure is not repeated here.

Fig. 3 shows a schematic configuration of an optical system 300 according to a third embodiment of the present application.

As shown in fig. 3, the optical system 300 includes a projection display device 310 and an imaging lens 350. The projection display device 310 includes a polarization beam splitter 311, an image generator 312, and an optical compensator 313. The imaging lens 350 is configured to project light carrying the image information output from the projection display device 310 onto at least two imaging planes.

In some embodiments, the polarization beam splitting element 311 is configured to polarize an incident light beam incident on the polarization beam splitting element 311 into at least two outgoing light beams of different directions. The image generating element 312 is located in the propagation path of at least one outgoing light beam, which is configured to modulate the outgoing light beam into information light based on image information. The optical compensation element 313 is located between the polarization beam splitting element 311 and the image generating element 312, and the optical compensation element 313 has a plurality of different thickness dimensions in the direction of the outgoing light beam. Illustratively, the optical compensation element 313 has sequentially increasing first, second, and third thicknesses in the direction of the outgoing light beam, as shown in fig. 3. The optical compensation element 313 includes a first portion 3131 having a first thickness, a second portion 3132 having a second thickness, and a third portion 3133 having a third thickness.

In detail, as shown in fig. 3, the incident light beam incident on the polarization splitting element 311 includes P-polarized light and S-polarized light. The P polarized light comprises a large part of P light and a small amount of stray light, and the S polarized light comprises a large part of S light and a small amount of stray light. The polarization beam splitter 311 has a characteristic of transmitting P-polarized light and reflecting S-polarized light. Therefore, after the P-polarized light and the S-polarized light are simultaneously incident on the polarization splitting element 311, the S-polarized light is reflected as an outgoing beam of the S-polarized light when passing through the polarization splitting element 311.

The S-polarized light exit beam of the first portion enters the image generating element 312 through the first portion optical compensation element 3131 having the first thickness. The optical compensation element 3131 can improve the purity of the portion of S polarized light, reduce parasitic light, and does not affect the polarization state of P polarized light. Alternatively, image-generating element 312 is a reflective image-generating element 312. When the image generating element 312 is in the bright state, the S-polarized light of the first portion may be modulated into P-polarized light and reflected, and the reflected P-polarized light of the first portion may be incident on the polarization beam splitter 311 after passing through the optical compensation element 3131 of the first portion. Since the optical compensation element 3131 does not affect the polarization state of the P-polarized light, and the polarization splitting element 311 has a property of transmitting the P-polarized light, the P-polarized light of the first portion is transmitted into the imaging lens 350 through the polarization splitting element 311 and is projected onto the first imaging plane 351.

Similarly, the second portion of the S-polarized light exit beam passes through the second portion of the optical compensation element 3132 having the second thickness and enters the image generation element 312. The optical compensation element 3132 may improve the purity of the portion of S polarized light, reduce parasitic light, and not affect the polarization state of P polarized light. When the image generating element 312 is in the bright state, the second portion of S polarized light may be modulated into P polarized light and reflected, and the reflected second portion of P polarized light may be incident on the polarization beam splitter 311 after passing through the optical compensation element 3132 of the second portion. Since the optical compensation element 3132 does not affect the polarization state of the P-polarized light, and the polarization splitting element 311 has a property of transmitting the P-polarized light, the second portion of the P-polarized light passes through the polarization splitting element 311, is transmitted into the imaging lens 350, and is projected onto the second imaging plane 352.

Similarly, the third portion of the S-polarized light exit beam passes through the third portion of the optical compensation element 3133 having the third thickness and enters the image generation element 312. The optical compensation element 3133 may improve the purity of the portion of S polarized light, reduce parasitic light, and not affect the polarization state of P polarized light. When the image generating element 312 is in the bright state, the S-polarized light of the third portion may be modulated into P-polarized light and reflected, and the reflected P-polarized light of the third portion may be incident on the polarization beam splitter 311 after passing through the optical compensation element 3133 of the third portion. Since the optical compensation element 3133 does not affect the polarization state of the P-polarized light, and the polarization splitting element 311 has a property of transmitting the P-polarized light, the P-polarized light of the third portion is transmitted into the imaging lens 350 through the polarization splitting element 311 and is projected onto the third imaging surface 353.

In the above-mentioned scheme, since the optical compensation element 313 has the first thickness, the second thickness and the third thickness that are sequentially increased, the materials of the optical compensation element 313 with different thicknesses cause the optical compensation element 313 with different refractive indexes in different portions, so that the P polarized light carrying the image information reflected by the image generating element 312 can be displayed on the first imaging plane 351, the second imaging plane 352 and the third imaging plane 353 at different positions, so as to form a three-screen system, which has a simple structure and low cost.

It will be appreciated that the present application is described by way of example only in the case where the optical compensation element 313 has three different thicknesses, and that the optical compensation element 313 may be provided to have four different thicknesses or more depending on the actual situation, thereby implementing a four-screen system or a multi-screen system, without limiting the present application.

In addition, in the case that the image generating element 312 is in the dark state, the S-polarized light incident on the image generating element 312 does not change the polarization state, the light modulated by the image generating element 312 is still S-polarized light, but the angle is deflected, and the optical compensating element 313 can shift the phase of the modulated S-polarized light in the dark state so as to inhibit the angular deviation of the polarization axis caused by the direction in which the S-polarized light irradiates the polarization splitting element 311, so that the polarization purity of the S-polarized light in the dark state can be effectively improved, and thus the S-polarized light can be totally reflected as much as possible when passing through the polarization splitting element 311, and part of the light is prevented from being transmitted to the imaging lens 350 to form dark-state stray light, thereby improving the contrast of the whole optical system 300.

In some embodiments, the side of the optical compensation element 313 facing the polarization splitting element 311 is a stepped surface, and the side of the optical compensation element 313 facing the image generating element 312 is a plane. The optical compensation element 313 has a plurality of different thicknesses by the arrangement of the stepped surface, and the processing process is simple and feasible. Illustratively, as shown in fig. 3, the side of the optical compensation element 313 facing the polarization splitting element 311 includes a first step surface, a second step surface, and a third step surface.

In some embodiments, the relative distance between the first imaging surface 351 and the second imaging surface 352 and the third imaging surface 353 ranges from approximately 20mm or more to 50mm or less. In the above scheme, controlling the distance between imaging planes and the position of the optical compensation element 313 can ensure the size of the whole machine and the full utilization of the optical compensation element 313.

In the case of no conflict, the other features in this embodiment may refer to the features of the first embodiment shown in fig. 1 or the second embodiment shown in fig. 2, and the disclosure is not repeated here.

Fig. 4 shows a flow diagram of a method 400 of manufacturing an optical system according to an embodiment of the application. As shown in fig. 4, the manufacturing method 400 of the optical system includes the steps of:

s420, arranging a polarization beam splitting element in the propagation direction of an incident light beam, wherein the polarization beam splitting element is configured to polarize the incident light beam into at least two emergent light beams in different directions;

s440, disposing at least one image generating element on a propagation path of the outgoing light beam, the image generating element being configured to modulate the outgoing light beam into information light based on the image information;

S460, arranging an optical compensation element between the polarization splitting element and the image generating element, wherein the optical compensation element is configured to enable at least part of emergent light beams and information light to pass through; and

s480, an imaging lens is disposed in a propagation direction of the information light, the imaging lens being configured to project the information light onto at least two imaging planes.

It should be understood that the steps shown in the method of manufacture 400 are not exclusive and that other steps may be performed before, after, or between any of the steps shown. Furthermore, some of the steps may be performed simultaneously or may be performed in a different order than shown in fig. 4.

In some embodiments, disposing an optical compensation element between the polarization splitting element and the image generating element in step S460 includes: an optical compensation element, which projects in the direction of the outgoing light beam so as to cover at least a part of the image generation element, is provided between the polarization splitting element and the image generation element.

Specifically, as shown in fig. 1, an optical system 100 manufactured using the manufacturing method shown in fig. 4 includes a projection display device 110 and an imaging lens 150. The projection display device 110 includes a polarization beam splitter 111, an image generator 112, and an optical compensation element 113. The imaging lens 150 is configured to project light carrying the image information output from the projection display device 110 onto at least two imaging planes.

The polarization beam splitter 111 is configured to polarize an incident light beam incident on the polarization beam splitter 111 into at least two outgoing light beams of different directions. The polarization splitting element 111 is illustratively a PBS prism. The image generating element 112 is located on the propagation path of at least one outgoing light beam, which is configured to modulate the outgoing light beam into information light based on image information. The optical compensation element 113 is located between the polarization beam splitter 111 and the image generation element 112, and the projection of the optical compensation element 113 in the direction of the outgoing light beam covers part of the image generation element 112, as shown with reference to fig. 1.

Illustratively, ΔL ranges from approximately 20mm or more to 50mm or less.

Alternatively, as shown in FIG. 1, the light source assembly 114 is an LD light source 1141 system. Optionally, the LD light source 1141 system includes an LD light source 1141, a beam expanding system 1142, a compound eye 1143, and a relay system 1144. The light beam emitted by the LD light source 1141 needs to be expanded by the beam expanding system 1142 and is uniformly transmitted by the compound eye 1143, and then the light beam is formed into an incident light beam (P polarized light and S polarized light) by the relay system 1144, and the incident light beam is incident on the polarization beam splitter 111.

Alternatively, as shown in FIG. 2, the light source assembly 214 is an LED light source system. The LED light source system includes an LED light source 2141, a collimating and beam combining system 2142, a compound eye 2143, and a relay system 2144. The divergent light beam emitted by the LED light source 2141 needs to be collimated by the collimating and beam-combining system 2142, and then is uniformly transmitted by the compound eye 2143, and then is transmitted by the relay system 2144 to form an incident light beam (P polarized light and S polarized light) to be incident on the polarization beam-splitting element 211.

In some embodiments, disposing an optical compensation element between the polarization splitting element and the image generating element in step S460 includes: an optical compensation element having a plurality of different thickness dimensions in the direction of the outgoing light beam is disposed between the polarization splitting element and the image generating element.

Specifically, as shown in fig. 3, an optical system 300 manufactured using the manufacturing method shown in fig. 4 includes a projection display device 310 and an imaging lens 350. The projection display device 310 includes a polarization beam splitter 311, an image generator 312, and an optical compensator 313. The imaging lens 350 is configured to project light carrying the image information output from the projection display device 310 onto at least two imaging planes.

In the case of no conflict, the other features in the present embodiment may refer to the optical system 100 shown in fig. 1 or the optical system 200 shown in fig. 2, and the disclosure is not repeated here.

The above description is only illustrative of the embodiments of the application and of the technical principles applied. It will be appreciated by those skilled in the art that the scope of the application is not limited to the specific combination of the above technical features, but also encompasses other technical solutions which may be formed by any combination of the above technical features or their equivalents without departing from the technical concept. Such as the above-mentioned features and the technical features disclosed in the present application (but not limited to) having similar functions are replaced with each other.

Claims

1. A projection display device, comprising:

a polarization beam splitting element configured to polarize an incident light beam incident to the polarization beam splitting element into at least two outgoing light beams in different directions;

at least one image generating element located on a propagation path of the outgoing light beam, configured to modulate the outgoing light beam into information light based on image information; and

and an optical compensation element, which is positioned between the polarization splitting element and the image generating element, and passes at least part of the emergent beam and the information light.

2. The projection display device of claim 1, wherein the projection display device comprises,

the projection of the optical compensation element in the direction of the outgoing light beam covers at least part of the image generating element.

3. The projection display device of claim 2, wherein,

the projection of the optical compensation element in the direction of the outgoing light beam does not exceed one half of the image generating element.

4. The projection display device of claim 2, wherein,

the thickness of the optical compensation element is less than or equal to 2mm.

5. The projection display device of claim 1, wherein the projection display device comprises,

The optical compensation element has a plurality of different thickness dimensions in the direction of the outgoing light beam.

6. The projection display device of claim 5, wherein the display device further comprises a display unit,

the side surface of the optical compensation element facing the polarization splitting element is a stepped surface; and

the side of the optical compensation element facing the image generating element is planar.

7. The projection display device of claim 5, wherein the display device further comprises a display unit,

the maximum thickness of the optical compensation element is less than or equal to 2mm.

8. The projection display device of any of claims 1-7, wherein,

the wavelength of the optical compensation element is more than or equal to 400nm and less than or equal to 700nm; and

the refractive index of the optical compensation element is more than or equal to 1.4 and less than or equal to 1.8.

9. An optical system, comprising:

the projection display device of any one of claims 1 to 8; and

and the imaging lens is configured to project the information light carrying the image information, which is output by the projection display device, onto at least two imaging surfaces.

10. A method of manufacturing an optical system, comprising:

disposing a polarizing beam splitting element in a propagation direction of an incident light beam, the polarizing beam splitting element configured to polarize the incident light beam into at least two differently directed outgoing light beams;

Disposing at least one image generating element on a propagation path of the outgoing light beam, the image generating element being configured to modulate the outgoing light beam into information light based on image information;

disposing an optical compensation element between the polarization splitting element and the image generating element, the optical compensation element configured to pass at least a portion of the outgoing light beam and the information light; and

an imaging lens is disposed in a propagation direction of the information light, the imaging lens being configured to project the information light onto at least two imaging surfaces.