CN116520626A

CN116520626A - Optical projection system and electronic device

Info

Publication number: CN116520626A
Application number: CN202310332354.5A
Authority: CN
Inventors: 鲁公涛; 赵云
Original assignee: Goertek Optical Technology Co Ltd
Current assignee: Goertek Optical Technology Co Ltd
Priority date: 2023-03-28
Filing date: 2023-03-28
Publication date: 2023-08-01

Abstract

The embodiment of the application discloses an optical projection system and electronic equipment; wherein the optical projection system comprises: the device comprises a light source module, a brightening device, a first light guide device and an imaging module; the light source module is used for generating projection light; the brightness enhancement device is positioned on the light path transmission path of the light source module and can convert the projection light into target light for projection imaging; the first light guide device is positioned on the transmission path of the target light; the imaging module is positioned on the coupled light transmission path of the first light guide device, the light coupled by the first light guide device directly enters the imaging module, and the light is emitted after being reflected for many times in the imaging module to form the light with image information. The scheme provided by the embodiment of the application can realize the small-volume and high-brightness design of the optical projection system.

Description

Optical projection system and electronic device

Technical Field

The application belongs to the technical field of optical projection, and particularly relates to an optical projection system and electronic equipment.

Background

In recent years, smart wearable devices are becoming more and more interesting and favored by consumers as a large class of electronic devices. Currently, smart wearable devices include augmented reality devices (AR, augmented ReaHity), virtual reality devices (VR), and Mediated reality devices (MR), XR devices, and the like. Taking an AR device as an example, the existing LCOS light engine used in the AR field generally has the defects of large volume and low light efficiency, so that the LCOS light engine cannot be used outdoors.

Disclosure of Invention

The present application is directed to an optical projection system and a new technical solution for an electronic device, which at least solves the problems of the existing optical projection system that the volume is large and the light efficiency is low.

According to a first aspect of the present application, an optical projection system is provided. The optical projection system includes:

the light source module is used for generating projection light;

the brightness enhancement device is positioned on the light path transmission path of the light source module and can convert the projection light into target light for projection imaging;

the first light guide device is positioned on the transmission path of the target light; the method comprises the steps of,

the imaging module is positioned on the coupled light transmission path of the first light guide device, light coupled by the first light guide device directly enters the imaging module, and the light is emitted after being reflected for many times in the imaging module to form light with image information.

Optionally, the optical projection system further comprises a brightness adjuster, the brightness adjuster being a linear polarizer;

the brightness regulator is positioned on the light-emitting path of the imaging module, light emitted by the imaging module can enter the brightness regulator, and the brightness regulator can regulate the light intensity according to the brightness of the external environment.

Optionally, the brightness enhancement device includes a light splitting element, a reflecting element and a first phase retarder, where the projection light impinges on the light splitting element, the light splitting element can reflect S light in the projection light and transmit P light, the P light propagates to the reflecting element, is reflected by the reflecting element to the first phase retarder, and emits S light after passing through the first phase retarder, so that the projection light is totally converted into S light and then enters the imaging module; wherein the S light is the target light.

Optionally, the first phase retarder is a half-wave plate.

Optionally, the optical projection system further includes a second light guide device, where the second light guide device is located at a side of the brightness adjuster away from the imaging module;

the second light guide device is an imaging waveguide sheet and is used for transmitting the light rays with the image information emitted by the imaging module and forming a projection image after the light rays are emitted.

Optionally, the first light guiding device includes a waveguide substrate, and a coupling-in region and a coupling-out region disposed on the waveguide substrate, where the projection light can be incident into the waveguide substrate through the coupling-in region, and propagated to the coupling-out region by total reflection, and then exit from the coupling-out region at the same angle as the incident angle;

The coupling-in area and the brightening device are adjacent and are arranged at intervals, and a light homogenizing element is arranged between the coupling-in area and the brightening device;

the coupling-out area is positioned on the light-in path of the imaging module.

Optionally, the dodging element and the coupling-in area are disposed opposite to each other; the dodging element comprises a compound spectacle lens.

Optionally, the imaging module comprises a polarizing element, a light splitting device, an LCOS chip and a lens group;

the polarizing element is positioned on the light incident path of the imaging module;

the light splitting device is positioned in the light path of the lens group;

the LCOS chip is positioned on one side of the light splitting device and can convert the polarization state of light to generate an image source.

Optionally, the light splitting device is a light splitting prism, the light splitting prism comprises two prisms connected with each other, and a light splitting film is arranged between the two prisms;

the beam-splitting prism comprises a light incident surface, an emergent surface, a first light-transmitting surface and a second light-transmitting surface;

the polarization element and the light incident surface are adjacently arranged, and the light splitting prism is provided with three surfaces and the lens group are adjacently arranged.

Optionally, the lens group includes a first lens located at one side of the exit surface, a second lens located at the first light-transmitting surface, and a gluing lens group located at one side of the second light-transmitting surface, and the gluing lens group is located between the second light-transmitting surface and the LCOS chip;

The second lens is a reflecting mirror, and a second phase retarder is arranged between the second lens and the first light-transmitting surface;

the gluing lens group comprises a third lens and a fourth lens which are glued with each other, the third lens is close to the second lens surface, the fourth lens is close to the LCOS chip, the third lens is a positive lens, and the fourth lens is a negative lens.

Optionally, the light splitting device is a light splitting sheet obliquely arranged at 45 degrees, and the light splitting sheet comprises a glass substrate and a light splitting film material arranged on the glass substrate.

Optionally, the brightness enhancement device and the imaging lens group are located on the same side of the first light guide device.

Optionally, the light source module comprises a light source, wherein the light source comprises a plurality of different light emitting chips and can emit light with different wave bands;

a collimation device and a light combining device are sequentially arranged on the light path transmission path of the light emitting chip;

wherein, the light combining device is an optical filter or a prism.

Optionally, the light source comprises a red light chip, a green light chip and a blue light chip which are sequentially arranged;

a first collimating device and a first optical filter are sequentially arranged on the optical path transmission path of the red light chip, a second collimating device and a second optical filter are sequentially arranged on the optical path transmission path of the green light chip, and a third collimating device and a third optical filter are sequentially arranged on the optical path transmission path of the blue light chip;

The first optical filter can reflect red light and transmit blue light and green light; the second optical filter can reflect green light and simultaneously transmit blue light; the third optical filter can reflect blue light; the first optical filter, the second optical filter and the third optical filter can combine three different wave bands into one beam of light.

a first collimating device and a prism A are sequentially arranged on the optical path transmission path of the red light chip, a second collimating device and a prism B are sequentially arranged on the optical path transmission path of the green light chip, a third collimating device and a prism C are sequentially arranged on the optical path transmission path of the blue light chip, the prism A, the prism B and the prism C are sequentially glued to form a glued prism, a blue-reflecting and red-transmitting film is arranged on the glued surface of the prism A and the prism B, and a green-reflecting and red-transmitting film is arranged on the glued surface of the prism B and the prism C; the gluing prism can combine three different wave bands into one beam of light.

According to a second aspect of the present application, there is also provided an electronic device. The electronic device includes:

A housing; and

the optical projection system of the first aspect.

The beneficial effects of this application lie in:

the embodiment of the application provides an optical projection system, which is an LCOS projection optical framework with small volume, and by introducing a brightening device and a light guide device between an illumination light path and an imaging light path, the illumination and imaging can share the light path, so that the original complex and large-volume relay part design between the illumination light path and the imaging light path is omitted, and under the condition of ensuring small volume, the light efficiency of the optical projection system can be greatly improved due to higher luminous flux under rated power consumption. The optical framework provided by the embodiment of the application can improve the optical performance while having a small volume, is beneficial to improving the use experience of a user, and provides a development direction for the miniaturization and high-brightness design of AR equipment.

Other features of the present application and its advantages will become apparent from the following detailed description of exemplary embodiments of the present application, which proceeds with reference to the accompanying drawings.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the application and together with the description, serve to explain the principles of the application.

FIG. 1 is a schematic diagram of an optical projection system according to an embodiment of the present disclosure;

FIG. 2 is a schematic diagram of a brightness enhancement device of an optical projection system according to an embodiment of the present disclosure;

FIG. 3 is a block diagram of a first light guide device of an optical projection system according to an embodiment of the present disclosure;

FIG. 4 is a schematic diagram of a light combining structure of an optical projection system according to an embodiment of the present disclosure;

fig. 5 is a schematic structural diagram of an imaging module of an optical projection system according to an embodiment of the present application.

Reference numerals illustrate:

1. a light source module; 101. a red light chip; 102. a green light chip; 103. a blue light chip; 104. a first alignment device; 105. a second collimating device; 106. a third collimating device; 107. a first optical filter; 108. a second optical filter; 109. a third filter; 110. a prism A; 111. a prism B; 112. a prism C; 2. a brightening device; 201. a first prism; 202. a second prism; 203. a third prism; 204. a spectroscopic element; 205. a reflective element; 206. a first phase retarder; 3. a first light guide device; 301. a waveguide substrate; 302. a coupling-in region; 303. a coupling-out region; 4. a brightness adjuster; 5. a second light guide device; 6. a light homogenizing element; 7. a polarizing element; 8. a spectroscopic device; 801. a light incident surface; 802. an exit surface; 803. a first light-transmitting surface; 804. a second light-transmitting surface; 9. LCOS chip; 10. a first lens; 11. a second lens; 12. a third lens; 13. a fourth lens; 14. a second phase retarder; 15. and a light-splitting film.

Detailed Description

Various exemplary embodiments of the present application will now be described in detail with reference to the accompanying drawings. It should be noted that: the relative arrangement of the components and steps, numerical expressions and numerical values set forth in these embodiments do not limit the scope of the present application unless it is specifically stated otherwise.

The following description of at least one exemplary embodiment is merely exemplary in nature and is in no way intended to limit the application, its application, or uses.

Techniques, methods, and apparatus known to one of ordinary skill in the relevant art may not be discussed in detail, but are intended to be part of the specification where appropriate.

In all examples shown and discussed herein, any specific values should be construed as merely illustrative, and not a limitation. Thus, other examples of exemplary embodiments may have different values.

It should be noted that: like reference numerals and letters denote like items in the following figures, and thus once an item is defined in one figure, no further discussion thereof is necessary in subsequent figures.

The optical projection system and the electronic device provided in the embodiments of the present application are described in detail below with reference to fig. 1 to 5.

The optical projection system provided by the embodiment of the application can be applied to an AR device, for example.

Referring to fig. 1, an optical projection system provided in an embodiment of the present application includes: the device comprises a light source module 1, a brightening device 2, a first light guide device 3 and an imaging module. The light source module 1 is used for generating projection light. The brightness enhancement device 2 is located on the optical path transmission path of the light source module 1, and can convert the projection light into target light for projection imaging. The first light guide device 3 is located on the transmission path of the target light. The imaging module is located on the coupled light transmission path of the first light guide device 3, the light coupled by the first light guide device 3 directly enters the imaging module, and the light is emitted after being reflected for many times in the imaging module to form the light with image information.

The optical projection system provided according to the above embodiments of the present application may be applied to an AR device, for example, to form an optical engine. In the optical projection system, the brightness enhancement device 2 and the first light guide device 3 are introduced between the light source module 1 for illumination and the imaging module for projection imaging, so that a large-size relay part (comprising a plurality of lenses) in a traditional optical architecture is omitted, and the effect of small size and high brightness of the optical projection system can be realized by the design.

The light source module is used as an illumination part of the whole optical framework, the emitted projection light is natural light, specifically, 50% of P light and 50% of S light are contained in the light source module, and in practice, the imaging part can only perform projection imaging by using one of the S light or the P light. Based on this, the light efficiency utilization is only 50% in theory, and the light efficiency is low.

In the optical projection system provided in the foregoing embodiment of the present application, the brightness enhancement device 2 is introduced between the light source module 1 and the imaging module, referring to fig. 1, the brightness enhancement device 2 can fully convert natural light (projection light) into S light (S light here is the target light mentioned in the foregoing embodiment), and this design can greatly improve the light efficiency of the entire optical projection system.

The optical projection system provided in the above embodiment of the present application further introduces an illumination optical waveguide between the light source module 1 and the imaging module, that is, the first light guide device 3 described above. The design allows the illumination section and the imaging section to share a common optical path. The first light guide device 3 has a thin-sheet structure, and optical devices such as a conventional relay lens group (an optical device which needs to be applied in a conventional projection optical system is a lens type steering system, and the volume and the weight of the optical device are larger than those of the first light guide device 3) are directly omitted after the optical device is introduced, so that the volume and the weight of the optical projection system are reduced.

The first light guide device 3 is introduced between the light source module 1 and the imaging module, so that the projection light (natural light) emitted by the light source module 1 can be introduced into the first light guide device 3. Furthermore, based on the nature of the light guide device, the projection light will exit from the first light guide device 3 and enter the imaging module at the same angle as when it is incident. That is, the first light guide device 3 can be used to collect the projection light into the imaging module, and the application of the light guide device is beneficial to improving the light efficiency.

According to the optical projection system provided in the above embodiment of the present application, the main optical path transmission path is: the light source module 1 can emit projection light, the projection light can be transmitted to the imaging module through the first light guide device 3, and the imaging module is used for projecting and imaging the received light.

According to the optical projection system provided by the embodiment of the application, the LCOS projection optical framework is small in size, and the brightening device 2 and the light guide device are introduced between the illumination light path and the imaging light path, so that the illumination and imaging can share the light path, the original complex and large-volume relay part design between the illumination light path and the imaging light path is omitted, and under the condition of ensuring small volume, the LCOS projection optical framework can have higher luminous flux under rated power consumption, and the light efficiency of the optical projection system can be greatly improved.

The optical framework provided by the embodiment of the application can improve the optical performance while being small in volume, is favorable for improving the use experience of a user, and provides a development direction for the miniaturization and high-brightness design of AR equipment.

According to the optical framework provided by the embodiment of the application, according to arrangement and selection of internal devices, the volume can be compressed, the weight can be reduced, the optical framework has higher luminous flux, and the aim of outdoor use of a user can be achieved.

According to the optical projection system provided by the embodiment, the optical performance can be improved while the volume miniaturization and the light weight design are realized. The method is very suitable for being applied to electronic equipment such as AR head-mounted equipment, and wearing comfort and immersive experience of a user can be improved.

In some examples of the present application, referring to fig. 1, the optical projection system further comprises a brightness adjuster 4, the brightness adjuster 4 being, for example, a linear polarizer. The brightness adjuster 4 is located on the light-emitting path of the imaging module. The light emitted by the imaging module can enter the brightness regulator 4, and the brightness regulator 4 can regulate the light intensity according to the brightness of the external environment.

According to the above example, the optical projection system provided by the present application introduces a brightness adjuster 4 on one side of the imaging module (e.g. on the side of the exit face 802 shown in fig. 1). Specifically, the brightness adjuster 4 is, for example, a linear polarizer, and can automatically adjust the light intensity according to the brightness of the external environment. Since the brightness adjuster 4 is of a sheet structure, it does not occupy a large space.

For example, the luminance adjuster 4 is a linear polarizer. The light output is highest when the polarization axis of the linear polarizer is parallel to the polarization axis of the polarizing element 7 in the imaging module. And when the polarization axis of the linear polarizer is perpendicular to the polarization axis of the polarizing element 7 in the imaging module, the light output amount is zero.

Of course, the luminance adjuster 4 may be a glass sheet on which the linear polarization film material is disposed. The glass material can improve the temperature resistance of the brightness adjuster 4 and reduce the production cost.

In some examples of the present application, referring to fig. 2, the brightness enhancement device includes a light splitting element 204, a reflecting element 205 and a first phase retarder 206, the projection light is incident on the light splitting element 204, the light splitting element 204 can reflect S light in the projection light and transmit P light, the P light propagates to the reflecting element 205, is reflected to the first phase retarder 206 by the reflecting element 205, and emits S light after passing through the first phase retarder 206, so that the projection light is totally converted into S light and then enters the imaging module; wherein the S light is the target light.

In the brightness enhancement device, in order to simplify the assembly of the light splitting element 204, the reflecting element 205 and the first phase retarder 206 in the light path frame, a plurality of prisms, for example, three prisms, may be introduced, and the three prisms may be designed to be sequentially glued together.

In one example, referring to fig. 2, the brightness enhancement device 2 includes a first prism 201, a second prism 202, and a third prism 203 that are glued in sequence, where the first prism 201 is located at a side close to the light source module 1, and the third prism 203 is located at a side close to the first light guide device 3. The first prism 201, the second prism 202 and the third prism 203 are all 45-degree triangular prisms; the hypotenuse of the first prism 201 and the hypotenuse of the second prism 202 are glued with each other, and a light splitting element 204 is arranged on the glued surface of the hypotenuse and the hypotenuse; one right-angle side of the second prism 202 and one right-angle side of the third prism 203 are glued to each other, a reflecting element 205 is disposed on the hypotenuse of the third prism 203, and the other right-angle side of the third prism 203 is adjacent to and spaced from the first light guiding device 3 and is provided with a first phase retarder 206.

That is, in the embodiment of the present application, the brightness enhancement device 2 may include a glued prism group, which includes, for example, the three sequentially glued prisms described above. The whole structure is simple in design and does not increase the process complexity. The brightness enhancement device 2 can fully convert natural light (projection light emitted from the light source module 1) into, for example, S light, which greatly improves the light efficiency of the optical projection system.

According to the direction shown in fig. 2, the projection light is natural light (e.g. RGB three-color light), which is emitted from the light source module 1, and the light source module 1 is located on the right side. Natural light enters the brightness enhancement device 2 from the first prism 201 located on the right side, and the light impinges on the light splitting element 204 (for example, PBS film). The S light in the natural light can be reflected and spread upwards, and the P light is transmitted and spread leftwards. The P-light is reflected by the reflective element 205 (reflective film) and propagates upward through the first retarder 206 (e.g., half-wave plate HWP).

It should be noted that, the prism in the brightness enhancement device may be replaced by another light-transmitting element to support the above-mentioned light-splitting element 204, the reflecting element 205, the first phase retarder 206, and the like.

Optionally, the first retarder 206 is a half-wave plate (HWP film).

The first phase retarder 206 may be, for example, coated or glued on the right-angle side of the third prism 203 near the first light guide 3.

Specifically, the half wave plate (HWP film) itself has a polarization axis, when an angle exists between the polarization axis and the polarization axis of the incident lightWhen the polarization axis of the outgoing light is rotated + >Therefore, when the polarization axis of the half-wave plate (HWP film) and the polarization axis of the P-ray are at an angle of 45 °, the emitted light from the half-wave plate (HWP film) becomes S light. At this time, all the natural light energy incident from the right side of the brightness enhancement device 2 is converted into S light, and then enters the imaging module.

In some examples of the present application, referring to fig. 1, the optical projection system further includes a second light guiding device 5, where the second light guiding device 5 is located on a side of the brightness adjuster 4 facing away from the imaging module; the second light guide device 5 is an imaging waveguide sheet, and is configured to transmit the light with the image information emitted by the imaging module, and form a projection image after the light is emitted.

According to the above example, in the optical projection system provided in this embodiment of the present application, an imaging waveguide, that is, the above second light guide device 5 is disposed on a side of the brightness adjuster 4 facing away from the imaging module, and the second light guide device 5 is used to transmit the light beam with the image information exiting from the imaging module to the human eye for projection imaging, which is different from the first light guide device 3. The light received by the second light guide device 5 is light with image information.

Alternatively, the second light guiding device 5 may be a diffractive optical waveguide, or may be a geometric optical waveguide. Can be adjusted according to actual needs, and is not limited in this embodiment of the present application.

It should be noted that, the coupling-in area of the second light guiding device 5 is opposite to the brightness adjuster 4, and both are located at the light emitting side of the imaging module.

In some examples of the present application, referring to fig. 1 and 3, the first light guiding device 3 includes a waveguide substrate 301, and a coupling-in region 302 and a coupling-out region 303 disposed on the waveguide substrate 301, where the projection light may enter the waveguide substrate 301 through the coupling-in region 302, propagate to the coupling-out region 303 through total reflection, and exit from the coupling-out region 303 at the same angle as the incident angle; the coupling-in area 302 is adjacent to and spaced from the brightness enhancement device 2, and a light homogenizing element 6 is disposed between the coupling-in area 302 and the brightness enhancement device 2; the coupling-out region 303 is located on the light-in path of the imaging module.

According to the above example, the first light guiding device 3 provided in the embodiment of the present application is an optical waveguide structure, which includes a waveguide substrate 301, an in-coupling region 302, and an out-coupling region 303. For example, the in-coupling region 302 and the out-coupling region 303 may be located on the same side of the waveguide substrate 301. After entering the waveguide substrate 301 from the coupling-in region 302, the light is totally reflected in the propagation region, propagates to the coupling-out region 303, and exits from the coupling-out region 303 to the imaging module.

It should be noted that, diffractive optical elements may be disposed in the coupling-in region 302 and the coupling-out region 303, or geometrical optical elements may be disposed. That is, the first light guide device 3 may be a diffractive light waveguide, a geometric light waveguide, or the like, which is not limited in the embodiment of the present application.

The first light guide device 3 is made of plastic, and has a refractive index of 1.55-1.65 and a thickness of 0.4-0.6 mm. The size of the coupling-in region 302 is for example between 3.3mm and 3.7mm, and the size of the coupling-out region 303 is for example between 1.5mm and 2mm. The first light guide device 3 is lighter and thinner, and compared with the traditional relay lens group, the volume and weight of the optical projection system can be obviously reduced.

In addition, it should be noted that, when the projection light is coupled into the interior of the waveguide substrate 301 through the coupling-in region 302 at a first angle, and propagates to the coupling-out region 303 through total reflection in the waveguide substrate 301, the projection light exits through the coupling-out region 303 at a first angle (the angle when the projection light enters the coupling-in region 302). This is the performance of the diffractive optical waveguide itself, which is beneficial to improving the light efficiency.

Optionally, the dodging element 6 and the coupling-in area 302 are disposed opposite to each other; the light homogenizing element 6 comprises a compound spectacle lens.

As the dodging element 6, the compound spectacle lens has a certain dodging and shaping function. For example, the circular light spot can be shaped into a rectangular light spot, and the brightness uniformity of the imaging light spot can be improved.

In addition, the fly-eye lens can be made of plastic materials, is thinner and lighter, and is beneficial to reducing the volume and weight of the whole optical projection system.

It should be noted that, in the conventional AR ray apparatus, a larger air gap between the compound lens and the imaging lens group is generally required to achieve higher optical efficiency. In the embodiment of the present application, by introducing the first light guiding device 3, which is used as an illumination light waveguide, the light propagates in, for example, the waveguide, and the propagation manner is multiple reflections, so that the space required for passing through the same optical path is smaller, which is beneficial to reducing the volume of the optical projection system.

In some examples of the present application, referring to fig. 1, the imaging module includes a polarizing element 7, a spectroscopic device 8, an LCOS chip 9, and a lens group. The polarization element 7 is located on the light incident path of the imaging module. The beam splitter 8 is located in the optical path of the lens group. The LCOS chip 9 is located at one side of the light splitting device 8, and the LCOS chip 9 can convert the polarization state of light to generate an image source.

The polarizing element 7 is, for example, a polarizer, which is located at one side of the coupling-out region 303 of the first light guide device 3, i.e. on the light incident path of the imaging module. Since the brightness enhancement device 2 cannot convert natural light into S light in percentage, the rest P light can directly exit through the light splitting device 8, resulting in a decrease in contrast. The polarizer 7 absorbs the remaining P light and retains the S light.

The lens group includes a plurality of lenses surrounding three sides of the light splitting device 8, as shown in fig. 1 and 5, and is used for amplifying and projecting the light with image information output by the LCOS chip 9 into the second light guiding device 5.

The LCOS chip 9 may convert the polarization state of the incident light to S light by adjusting the voltage of the pixel, so as to generate an image source.

It should be noted that, the light splitting device 8 may be a light splitting prism or a light splitting sheet, so that the design of the whole imaging module is flexible and higher.

For example, the spectroscopic device 8 is a spectroscopic prism.

Specifically, referring to fig. 1, the light splitting device 8 is a light splitting prism, the light splitting prism includes two prisms connected to each other, a fourth prism and a fifth prism, and a light splitting film 15 is disposed between the fourth prism and the fifth prism. The light splitting prism includes a light incident surface 801, an emergent surface 802, a first light transmitting surface 803 and a second light transmitting surface 804. The polarizing element 7 is disposed adjacent to the light incident surface 801, and the dichroic prism has three surfaces disposed adjacent to the lens group.

Optionally, the lens group includes a first lens 10 located at the exit surface 802 side, a second lens 11 located at the first light-transmitting surface 803, and a gluing lens group located at the second light-transmitting surface 804 side, and the gluing lens group is located between the second light-transmitting surface 804 and the LCOS chip 9. The second lens 11 is a reflecting mirror, and a second phase retarder 14 is disposed between the second lens 11 and the first light-transmitting surface 803. The cemented lens assembly comprises a third lens 12 and a fourth lens 13 cemented with each other, wherein the third lens 12 is close to the second lens surface 804, the fourth lens 13 is close to the LCOS chip 9, the third lens 12 is a positive lens, and the fourth lens 13 is a negative lens.

Referring to fig. 1, the light splitting device is, for example, a light splitting prism, where the light splitting prism is formed by gluing two triangular prisms with an angle of 45 ° and the glue layer is a piece of PBS film (i.e., the light splitting film 15 described above), and the PBS film can reflect S light and transmit P light.

Specifically, referring to fig. 1, the lens on the right side of the beam splitter prism is, for example, a second lens 11, and referring to the optical path shown in fig. 1, it is known that the second lens 11 is, for example, a mirror. A second phase retarder 14 is arranged between the mirror and the splitting prism, for example. A cemented lens group is disposed between the beam splitter prism and the LCOS chip 9, and includes, for example, the two lenses, wherein the side close to the beam splitter prism is a positive lens, and the side close to the LCOS chip 9 is a negative lens.

The refractive index of the positive lens is, for example, 1.6 to 1.65, and the refractive index of the negative lens is, for example, 1.93 to 1.98. Under the refractive index, the processing difficulty of the lens is not increased, and the imaging requirement of human eyes can be completely met.

Wherein the second phase retarder 14 is for example a quarter wave plate.

Of course, the form of the beam splitter 8 in the imaging module is not limited to the beam splitter prism in the above example, and may be a beam splitter disposed obliquely, as shown in fig. 5.

In one example, referring to fig. 5, the light splitting device 8 is a light splitting sheet disposed at an angle of 45 °, and the light splitting sheet includes a glass substrate and a light splitting film material disposed on the glass substrate.

That is, the light-splitting sheet in the above example may be used instead of the light-splitting prism. Specifically, the light-splitting sheet is made of glass, the thickness of the light-splitting sheet is 0.3 mm-0.5 mm, the refractive index of the light-splitting sheet is 1.5-1.55, and a layer of PBS film is attached to the surface of the glass to realize polarization light-splitting effect.

The solution of the present example has the advantage of being lighter in weight than the design of the beam splitting prism, which is advantageous for the light weight of the optical projection system. However, since the light-splitting sheet is inclined by 45 ° and is made of a glass material, the assembly difficulty is slightly greater than that of the light-splitting prism.

The scheme of taking the beam splitter prism as the beam splitter of the imaging module has the advantages that the definition of the imaging module is very good, and the MTF is reduced.

In some examples of the present application, referring to fig. 1, the brightness enhancement device 2 and the imaging lens group are located on the same side of the first light guide device 3.

In the above example, the arrangement manner of the brightness enhancement device 2 and the imaging lens group is that the brightness enhancement device and the imaging lens group are located on the same side of the first light guide device 3, so that the arrangement manner of each device in the whole optical projection system is more compact, and the size is reduced.

In some examples of the present application, referring to fig. 1 and 4, the light source module 1 includes a light source, where the light source includes a plurality of different light emitting chips, and can emit light in different wavelength bands; a collimation device and a light combining device are sequentially arranged on the light path transmission path of the light emitting chip; wherein, the light combining device is an optical filter or a prism.

Wherein each of the light emitting chips is, for example, an LED. Different light emitting chips can emit light rays of different wave bands. On the basis of this, the light source can emit light of different wavebands, for example forming an RGB light source.

For example, the light source module 1 can emit red light, green light and blue light (i.e. RGB three-color light), and the structure of the waveguide substrate 301 of the first light guide device 3 can be designed into a three-layer stacked structure, i.e. a red light substrate, a green light substrate and a blue light substrate, so as to respectively perform diffraction transmission on the RGB three-color light.

In order to achieve the light and thin and miniaturized design of the whole optical projection system, the thickness of the first light guide device 3 is not easy to be excessively large. For example, the thickness may range from 0.5mm to 0.8mm.

The red light R, the green light G and the blue light B are all visible light, and the three have different wave bands respectively. For example, the red light R has a wavelength band of 590nm to 640nm, the green light G has a wavelength band of 510nm to 560nm, and the blue light B has a wavelength band of 440nm to 490nm.

The optical projection system provided according to the above embodiment of the present application includes a light source module 1, where the light source module 1 is an illumination light path design, and belongs to an illumination light path portion of the optical projection system.

The light source module 1 is, for example, a multicolor light source. The light source module 1 can emit projection light for projection, and the projection light can include light in a plurality of different wave bands, such as green light, red light, blue light, and the like. Of course, the light source module 1 in the embodiment of the present application includes, but is not limited to, light capable of emitting light of three colors, and light of other colors may be emitted as long as visible light can be emitted.

It should be emphasized that the light source of the light source module 1 is responsible for emitting divergent projection light, and the light needs to be collimated into parallel light by, for example, a collimating device, and then the light beams with different wavebands are combined into a beam of light by the light combining device and then are incident to the brightening device 2 and the first light guiding device 3.

The light combining device may, for example, include a filter as shown in fig. 1, or may be a prism as shown in fig. 4, which is not limited in this application.

Optionally, the form of the collimating device comprises a collimating lens group or a single super surface lens.

Fig. 1 and 4 show the form of a collimator lens set. The collimating lens group comprises a first collimating lens and a second collimating lens which are arranged along the same optical axis at intervals.

Taking the red light chip 101 as an example, the red light emitted by the red light chip 101 can sequentially pass through the first collimating lens and the second collimating lens, so that 0-degree parallel light can be formed to emit, and the collimating effect on the red light is realized. Note that, the principle of collimation of the green light and the blue light is the same as that of the red light, and the description thereof will not be repeated here.

For a collimating lens group, it is designed to include two collimating lenses. The design allows for a smaller curvature for each collimating optic, and thus a smaller thickness for the collimating optic. Compared with the design of a single collimating lens, the design of the combination of the two collimating lenses is actually smaller than the thickness of the design of the single collimating lens, which is beneficial to reducing the size of the whole light source module along the thickness direction and simultaneously reducing the manufacturing difficulty of the collimating lens.

Of course, the collimating device may also employ a single super-surface lens. The super-surface lens is lighter and thinner, but may increase production cost, and the super-surface lens may be considered without considering production cost.

In one example, referring to fig. 1, the light source includes a red light chip 101, a green light chip 102, and a blue light chip 103, which are sequentially disposed. The first collimating device 104 and the first optical filter 107 are sequentially arranged on the optical path transmission path of the red light chip 101, the second collimating device 105 and the second optical filter 108 are sequentially arranged on the optical path transmission path of the green light chip 102, and the third collimating device 106 and the third optical filter 109 are sequentially arranged on the optical path transmission path of the blue light chip 103. Wherein the first filter 107 can reflect red light and transmit blue light and green light; the second filter 108 can reflect green light and transmit blue light; the third filter 109 can reflect blue light; the first filter 107, the second filter 108, and the third filter 109 can combine three different wavelength bands into one beam of light.

The first collimating device 104 is a blue collimating lens group, and is configured to shrink a divergence angle of blue light, and collimate the blue light into parallel light. The second collimating device 105 is a green collimating lens group, and is used for shrinking the divergence angle of the green light and collimating the green light into parallel light. The third collimating device 106 is a red collimating lens group, and is configured to shrink the divergence angle of red light, and collimate the red light into parallel light.

In one example, referring to fig. 4, the light source includes a red light chip 101, a green light chip 102, and a blue light chip 103, which are sequentially disposed. A first collimating device 104 and a prism a110 are sequentially arranged on the optical path transmission path of the red light chip 101, a second collimating device 105 and a prism B111 are sequentially arranged on the optical path transmission path of the green light chip 102, a third collimating device 106 and a prism C112 are sequentially arranged on the optical path transmission path of the blue light chip 103, the prism a110, the prism B111 and the prism C112 are sequentially glued to form a glued prism, a blue-reflecting red-transmitting film is arranged on the glued surface of the prism a110 and the prism B111, and a green-reflecting red-transmitting blue film is arranged on the glued surface of the prism B111 and the prism C112; the gluing prism can combine three different wave bands into one beam of light.

Referring to fig. 4, a bonding prism formed by bonding the prism a110, the prism B111 and the prism C112 is a combined light path, and functions to combine the RGB three-color light into one beam. In the above example, referring to fig. 4, the bonding surfaces of the bonding prisms are respectively attached with films reflecting/transmitting different wave bands, so that three-color light can be combined into one beam. The refractive index of the cemented prism is, for example, 1.85 to 1.95.

Regarding the light combining device shown in the above two examples, the light combining device in the form of the optical filter has the characteristic of lighter weight, which is beneficial to realizing the light weight of the optical projection module. And the prism-shaped light combining device can well shrink the LED light emitting angle. Can be flexibly selected according to actual conditions in application.

According to the optical projection system provided by the embodiment of the application, a light guide device and a brightness enhancement device are introduced between the light source module 1 and the imaging module. The brightness enhancement device can increase the brightness of the LCOS optical engine by one time so as to meet the outdoor use requirement of a user. The light guide device is an illumination light waveguide, so that the space required by the relay part is greatly shortened on the premise of ensuring the optical path of the relay part, and the volume of the optical projection system is reduced.

In yet another aspect, an embodiment of the present application further provides an electronic device. The electronic device comprises a housing and an optical projection system as described above.

The electronic device is, for example, a wearable device, and the wearable device is, for example, AR smart glasses or AR smart helmets.

The specific implementation manner of the electronic device in the embodiment of the present application may refer to the embodiment of the optical projection system, so at least the technical solution of the embodiment has all the beneficial effects, which are not described in detail herein.

Although specific embodiments of the present application have been described in detail by way of example, it will be appreciated by those skilled in the art that the above examples are for illustration only and are not intended to limit the scope of the present application. It will be appreciated by those skilled in the art that modifications may be made to the above embodiments without departing from the scope and spirit of the present application. The scope of the application is defined by the appended claims.

Claims

1. An optical projection system, comprising:

the light source module (1), the said light source module (1) is used for producing the projection light;

the brightness enhancement device (2) is positioned on the light path transmission path of the light source module (1) and can convert the projection light into target light for projection imaging;

A first light guide device (3), wherein the first light guide device (3) is positioned on the transmission path of the target light; the method comprises the steps of,

the imaging module is positioned on the coupled light transmission path of the first light guide device (3), light coupled by the first light guide device (3) directly enters the imaging module, and the light is emitted after being reflected for many times in the imaging module to form light with image information.

2. An optical projection system according to claim 1, characterized in that the optical projection system further comprises a brightness adjuster (4), the brightness adjuster (4) being a linear polarizer;

the brightness adjuster (4) is located on the light-emitting path of the imaging module, light emitted by the imaging module can enter the brightness adjuster (4), and the brightness adjuster (4) can adjust light intensity according to the brightness of external environment.

3. The optical projection system according to claim 1, wherein the brightness enhancement device (2) comprises a light splitting element (204), a reflecting element (205) and a first phase retarder (206), the projection light rays strike the light splitting element (204), the light splitting element (204) can reflect S light in the projection light rays and transmit P light, the P light propagates to the reflecting element (205), is reflected to the first phase retarder (206) by the reflecting element (205), and emits S light after passing through the first phase retarder (206) so as to convert the projection light rays into S light all and enter the imaging module; wherein the S light is the target light.

4. An optical projection system according to claim 3, characterized in that the first phase retarder (206) is a half-wave plate.

5. An optical projection system according to claim 2, characterized in that the optical projection system further comprises a second light guide device (5), the second light guide device (5) being located on the side of the brightness adjuster (4) facing away from the imaging module;

the second light guide device (5) is an imaging waveguide sheet and is used for transmitting the light rays with the image information emitted by the imaging module and forming a projection image after the light rays are emitted.

6. The optical projection system according to claim 1, wherein the first light guiding device (3) comprises a waveguide substrate (301), and a coupling-in region (302) and a coupling-out region (303) provided on the waveguide substrate (301), wherein the projection light can enter the waveguide substrate (301) via the coupling-in region (302) and propagate through total reflection to the coupling-out region (303) and exit the coupling-out region (303) at the same angle as the incident angle;

the coupling-in area (302) and the brightening device (2) are adjacent and are arranged at intervals, and a light homogenizing element (6) is arranged between the coupling-in area (302) and the brightening device (2);

The coupling-out region (303) is located on the light-in path of the imaging module.

7. The optical projection system according to claim 6, wherein the light homogenizing element (6) is arranged opposite the coupling-in region (302); the dodging element (6) comprises a compound spectacle lens.

8. The optical projection system according to claim 1, wherein the imaging module comprises a polarizing element (7), a light splitting device (8), an LCOS chip (9) and a lens group;

the polarizing element (7) is positioned on the light entering path of the imaging module;

the light splitting device (8) is positioned in the light path of the lens group;

the LCOS chip (9) is positioned on one side of the light splitting device (8), and the LCOS chip (9) can convert the polarization state of light rays to generate an image source.

9. An optical projection system according to claim 8, characterized in that the light-splitting device (8) is a light-splitting prism, which light-splitting prism comprises two prisms connected to each other, and a light-splitting film (15) is arranged between the two prisms;

the light splitting prism comprises a light incident surface (801), an emergent surface (802), a first light transmitting surface (803) and a second light transmitting surface (804);

the polarization element (7) and the light incident surface (801) are adjacently arranged, and the light splitting prism is provided with three surfaces and the lens group are adjacently arranged.

10. The optical projection system of claim 9, wherein the lens group comprises a first lens (10) located on the exit face (802) side, a second lens (11) located on the first light-transmitting face (803) side, and a cemented lens group located on the second light-transmitting face (804) side, and the cemented lens group is located between the second light-transmitting face (804) and the LCOS chip (9);

the second lens (11) is a reflecting mirror, and a second phase retarder (14) is arranged between the second lens (11) and the first light-transmitting surface (803);

the gluing lens group comprises a third lens (12) and a fourth lens (13) which are glued with each other, wherein the third lens (12) is close to the second light-transmitting surface (804), the fourth lens (13) is close to the LCOS chip (9), the third lens (12) is a positive lens, and the fourth lens (13) is a negative lens.

11. An optical projection system according to claim 8, characterized in that the light-splitting device (8) is a light-splitting sheet arranged at an angle of 45 °, the light-splitting sheet comprising a glass substrate and a light-splitting film material arranged on the glass substrate.

12. An optical projection system according to claim 1, characterized in that the brightness enhancement means (2) and the imaging lens group are located on the same side of the first light guide (3).

13. An optical projection system according to claim 1, characterized in that the light source module (1) comprises a light source comprising a plurality of different light emitting chips capable of emitting light of different wavelength bands;

wherein, the light combining device is an optical filter or a prism.

14. The optical projection system of claim 13, wherein the light source comprises a red light chip (101), a green light chip (102) and a blue light chip (103) arranged in this order;

a first collimating device (104) and a first optical filter (107) are sequentially arranged on the optical path transmission path of the red light chip (101), a second collimating device (105) and a second optical filter (108) are sequentially arranged on the optical path transmission path of the green light chip (102), and a third collimating device (106) and a third optical filter (109) are sequentially arranged on the optical path transmission path of the blue light chip (103);

wherein the first filter (107) is capable of reflecting red light and transmitting blue light and green light; the second optical filter (108) can reflect green light and transmit blue light; the third filter (109) can reflect blue light; the first optical filter (107), the second optical filter (108) and the third optical filter (109) can combine light rays of three different wave bands into one beam.

15. The optical projection system of claim 13, wherein the light source comprises a red light chip (101), a green light chip (102) and a blue light chip (103) arranged in this order;

a first collimating device (104) and a prism A (110) are sequentially arranged on a light path transmission path of the red light chip (101), a second collimating device (105) and a prism B (111) are sequentially arranged on a light path transmission path of the green light chip (102), a third collimating device (106) and a prism C (112) are sequentially arranged on a light path transmission path of the blue light chip (103), the prism A (110), the prism B (111) and the prism C (112) are sequentially glued to form a glued prism, a blue-reflection red-transmission film is arranged on a gluing surface of the prism A (110) and the prism B (111), and a green-reflection red-transmission film is arranged on a gluing surface of the prism B (111) and the prism C (112); the gluing prism can combine three different wave bands into one beam of light.

16. An electronic device, comprising:

a housing; and

the optical projection system of any of claims 1-15.