CN112540502A

CN112540502A - Projection display equipment and projection optical machine thereof

Info

Publication number: CN112540502A
Application number: CN202011540741.0A
Authority: CN
Inventors: 魏一振; 陈淑丹; 张卓鹏
Original assignee: Hangzhou Guangli Technology Co ltd
Current assignee: Hangzhou Guangli Technology Co ltd
Priority date: 2020-12-23
Filing date: 2020-12-23
Publication date: 2021-03-23

Abstract

The invention discloses a projection optical machine of projection display equipment, which comprises a light source part, an optical waveguide, an image source chip and a projection lens, wherein the light source part is arranged on the light waveguide; the optical waveguide is of a plate-shaped structure, the surface of the first end of the optical waveguide is provided with a coupling-in element, and the surface of the second end of the optical waveguide is provided with a coupling-out element; the optical waveguide is used for coupling light output by the light source component into the optical waveguide through the coupling-in element, the light is transmitted to the second end of the optical waveguide and is coupled out through the coupling-out element and enters the image source chip, so that the image source chip reflects and emits projection light to the second end of the optical waveguide, and the projection light is transmitted through the second end of the optical waveguide, enters the projection lens and is output. In the projection display equipment's of this application, the optical waveguide that adopts the flat structure replaces polarization beam splitter for projection display equipment overall structure is the flattening, is favorable to installation and use in equipment such as AR glasses. The application also provides a projection display device with the beneficial effects.

Description

Projection display equipment and projection optical machine thereof

Technical Field

The present invention relates to the field of optical systems, and in particular, to a projection optical machine of a projection display device and a projection display device.

Background

The projection optical machine is one of the important components of projection display equipment, mainly comprises an illumination light source, an image source and a projection lens, wherein light rays output by the illumination light source are projected onto the image source, projection light rays with a projection image are reflected and emitted from the image source, and the projection light rays are output by the projection lens.

With the development of projection display technology and the increasingly wide application of projection display equipment, people have higher requirements on the convenience of carrying and using the display equipment, and therefore, how to reasonably set the shape and structure of the projection display equipment in various different application equipment is one of the problems of the projection display technology industry needing research.

Disclosure of Invention

The invention aims to provide a projection optical machine of projection display equipment and the projection display equipment, which are beneficial to the application of the projection display equipment in various different environments.

In order to solve the technical problem, the invention provides a projection optical machine of projection display equipment, which comprises a light source part, an optical waveguide, an image source chip and a projection lens, wherein the first end of the optical waveguide is arranged on an output light path of the light source part;

the optical waveguide is of a plate-shaped structure, a coupling-in element is arranged on the surface of a first end of the optical waveguide, and a coupling-out element is arranged on the surface of a second end of the optical waveguide;

the optical waveguide is used for coupling light output by the light source component into the optical waveguide through the coupling-in element, the light is transmitted to the second end of the optical waveguide and coupled out and emitted to the image source chip through the coupling-out element, so that the image source chip reflects and emits projection light to the second end of the optical waveguide, and the projection light is transmitted through the second end of the optical waveguide, enters the projection lens and is output.

Optionally, the light source component comprises a light source and a light wave modulation device arranged on an output light path of the light source; the light wave modulation device is used for modulating the light output by the light source into first circularly polarized light;

a light modulation device is arranged between the image source chip and the coupling-out element; the light adjusting device is used for modulating the projection light emitted from the image source chip into second circularly polarized light;

the rotating directions of the first circularly polarized light and the second circularly polarized light are opposite, and the coupling-out element is a polarization holographic grating which reflects and diffracts the first circularly polarized light and transmits the second circularly polarized light.

Optionally, the image source chip is an LCOS chip; the dimming device is a first 1/4 wave plate.

Optionally, the light wave modulation device includes a polarizer and a second 1/4 wave plate, and an included angle between a fast axis of the second 1/4 wave plate and a polarization direction of the polarizer is 45 degrees.

Optionally, the light source is a laser light source, and a speckle removing device is further arranged on an output light path of the laser light source;

the spot-eliminating device is an electric control polaroid device and comprises a spot-eliminating polaroid and a TN (twisted nematic) liquid crystal box, and the spot-eliminating polaroid is arranged on the surface of the TN liquid crystal box;

or the speckle removing device is an electric control PDLC panel.

Optionally, the PDLC panel is disposed adjacent to or embedded within the first end of the optical waveguide.

Optionally, a beam expanding and collimating device is further disposed between the light source and the light wave modulation device.

Optionally, the coupling-in element is any one of a surface relief grating, a holographic grating, and a PVG grating.

A projection display device comprising a light engine of the projection display device as defined in any of the above.

Optionally, the projection display device is AR glasses.

The invention provides a projection optical machine of projection display equipment, which comprises a light source part, an optical waveguide, an image source chip and a projection lens, wherein the first end of the optical waveguide is arranged on an output light path of the light source part; the optical waveguide is of a plate-shaped structure, a coupling-in element is arranged on the surface of the first end of the optical waveguide, and a coupling-out element is arranged on the surface of the second end of the optical waveguide; the optical waveguide is used for coupling light output by the light source component into the optical waveguide through the coupling-in element, the light is transmitted to the second end of the optical waveguide and is coupled out through the coupling-out element and enters the image source chip, so that the image source chip reflects and emits projection light to the second end of the optical waveguide, and the projection light is transmitted through the second end of the optical waveguide, enters the projection lens and is output.

In the projection display device's of this application projection ray apparatus, light source part and image source chip set up the first end and the second end at the optical waveguide respectively, make the illumination light of light source part output couple out input to the image source chip after the second end of conducting to the optical waveguide through total reflection in the optical waveguide, for the structure that adopts square and the great optical element of volume such as polarization beam splitter to conduct the light beam of light source part output to image source chip surface among the prior art usually, plate structure's optical waveguide is littleer for the thickness of polarization beam splitter, be favorable to reducing the whole volume of projection ray apparatus, and make projection ray apparatus overall structure flattening, be favorable to installation and use in equipment such as AR glasses.

The application also provides a projection display device with the beneficial effects.

Drawings

In order to more clearly illustrate the embodiments or technical solutions of the present invention, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art that other drawings can be obtained based on these drawings without creative efforts.

FIG. 1 is a schematic diagram of an optical path structure of a projection optical engine in the prior art;

fig. 2 is a schematic view of an optical path structure of a projection optical machine of a projection display device according to an embodiment of the present application.

Detailed Description

As shown in fig. 1, a projection optical machine of a conventional projection display device generally needs to be provided with a polarization beam splitter 02 on an output optical path of an illumination system 01, and an illumination light is guided to the surface of an image source 03 through the polarization beam splitter 02 and then is transmitted to a lens 04 through the polarization beam splitter 02 to be output to the display device.

The polarizing beam splitter 02 is a cube structure formed by splicing two triangular prisms, occupies a large space and a large volume, so that the structural volume of the whole projection light machine is large, and the projection light machine is difficult to adjust in appearance due to the fact that the projection light machine is suitable for installation of various display devices.

For example, when the projection optical engine is applied to the AR glasses, the projection optical engine is generally disposed in the temple of the glasses, and the polarization beam splitter 02 is of a cube structure, which may result in a larger thickness dimension of the whole projection optical engine, and further results in a larger thickness of the temple, so that the temple of the projection optical engine is too wide or too thick, which brings uncomfortable use experience to the user.

Of course, optical elements such as prisms and beam splitters are used instead of the polarization beam splitter in the prior art, but the spatial volume occupied by the optical elements is similar to that of the polarization beam splitter, and the optical elements cannot substantially affect the overall structure of the projection light engine.

Therefore, the projection optical machine of the projection display equipment can reduce the whole thickness of the projection optical machine to a certain extent to realize the flattening of the projection optical machine, and is favorable for adapting to the application of the projection optical machine in various different display equipment.

In order that those skilled in the art will better understand the disclosure, the invention will be described in further detail with reference to the accompanying drawings and specific embodiments. It is to be understood that the described embodiments are merely exemplary of the invention, and not restrictive of the full scope of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

As shown in fig. 2, fig. 2 is a schematic structural diagram of a projection optical engine of a projection display device provided in the embodiment of the present application, where the projection optical engine may include:

a light source unit 1; based on the projection requirement of the projection display device, the general light source part 1 adopts a part capable of outputting white light, red, green and blue light sources can be configured in the light source part 1, and white light rays are obtained by uniformly mixing the three light sources.

An optical waveguide 2 having a first end disposed on an output optical path of the light source section 1; the image source chip 3 and the projection lens 4 are respectively arranged on two opposite sides of the second end of the optical waveguide 2;

the optical waveguide 2 is a plate-shaped structure, the surface of the first end of the optical waveguide 2 is provided with a coupling-in element 21, and the surface of the second end of the optical waveguide 2 is provided with a coupling-out element 22;

the optical waveguide 2 may be a light-transmitting plate having a plate-like structure or other structures with a refractive index larger than that of air. For example, a light-transmitting glass plate is possible, without excluding a light-transmitting plastic plate, as long as the light can be conducted in the light guide 2 by total reflection. The coupling-in element 21 may be any one of a surface relief grating, a holographic grating, and a PVG grating, and similarly the coupling-out element 22 may also adopt a grating structure. Of course, it is also conceivable that the coupling-out element 22 and the coupling-in element 21 are provided at the end of the optical waveguide 2 by bonding with an alternative prism or the like.

The optical waveguide 2 is used for coupling the light output by the light source component 1 into the optical waveguide 2 through the coupling-in element 21, conducting the light to the second end of the optical waveguide 2 through total reflection, and coupling and exiting the light from the optical waveguide 2 to the surface of the image source chip 3 through the coupling-out element 22, so that the light incident on the surface of the image source chip 3 forms projection light, and transmits the projection light to the projection lens 4 through the second end of the optical waveguide 2 and outputs the projection light.

As shown in fig. 2, the optical waveguide 2 has a generally plate-like structure, and specifically, a strip-like plate-like structure may be adopted, which is smaller in thickness than the polarization beam splitter. The light source part 1 is arranged at a first end of the optical waveguide 2, light output by the light source part 1 is incident from the first end of the optical waveguide 2, the first end of the optical waveguide 2 is provided with a coupling-in element 21, the light output by the light source part 1 is coupled into the optical waveguide 2 from the first end of the optical waveguide 2, the light is transmitted in the optical waveguide 2 in a total reflection manner, when the light is transmitted to a second end of the optical waveguide 2 in the total reflection manner in the optical waveguide 2, the light is coupled out from the second end of the optical waveguide 2 through a coupling-out element 22 at the second end of the optical waveguide 2, an image source chip 3 is arranged on the coupling-out path, the coupling-out light is incident to the surface of the image source chip 3 to form projection light reflected and emitted from the surface of the image source chip 3, and the projection light is transmitted to a projection.

Based on fig. 1, it can be determined that, in comparison with a conventional projection optical engine using a polarization beam splitter, the projection optical engine provided in the present application uses the optical waveguide 2 of a flat structure to replace the polarization beam splitter, thereby reducing the overall thickness of the projection optical engine to a certain extent, realizing the flat structure of the projection optical engine, enabling the projection optical engine to be well adapted to long and narrow installation environments similar to glasses legs, and being beneficial to the wide application of projection display equipment.

Further, as shown in fig. 1, the image source chip 3 and the projection lens 4 are respectively disposed at two sides of the second end of the optical waveguide 2, and the projection light emitted from the image source chip 3 can be incident to the projection light only after passing through the transmission optical waveguide 2. The coupling-out element 22 at the second end of the optical waveguide 2 inevitably affects the transmittance of the projection light when the projection light is transmitted through the second end of the optical waveguide 2, so that only part of the projection light can be incident on the projection lens 4, and the brightness of the projection image formed by the projection light output by the projection lens 4 is reduced, which affects the imaging effect of the projection display device.

To this end, in an alternative embodiment of the present application, the light source component 1 includes a light source 10 and a light wave modulation device 12 disposed on an output light path of the light source 10;

the light wave modulation device 12 is used for modulating the light output by the light source 10 into first circularly polarized light;

a light modulation device 5 is arranged between the image source chip 3 and the coupling-out element 22; the light adjusting device 5 is used for modulating the projection light emitted from the image source chip 3 into second circularly polarized light;

the coupling-out element is a polarization holographic grating which reflects and diffracts the first circularly polarized light and transmits the second circularly polarized light.

For example, the image source chip 3 may be an LCOS chip, and the dimming device 5 disposed between the image source chip 3 and the coupling-out element 22 is a first 1/4 wave plate with adjustable angle;

the first 1/4 wave plate is used for converting the first circularly polarized light coupled out from the optical waveguide 2 into linearly polarized light to be incident on the image source chip 3, and converting the linearly polarized light reflected and emergent from the surface of the image source chip 3 into second circularly polarized light;

as shown in fig. 2, the light wave modulation device 12 is used for modulating the light output by the light source 10 into a first circularly polarized light; the first circularly polarized light is coupled into the optical waveguide 2 by the coupling-in element 21 and is transmitted to the second end of the optical waveguide 2, because the coupling-out element 22 is a polarization holographic grating, the first circularly polarized light is reflected and diffracted by the first polarized light, so that the first circularly polarized light is coupled out of the optical waveguide 2 and enters the first 1/4 wave plate, the first circularly polarized light can form linearly polarized light after passing through the first 1/4 wave plate and enters the surface of the image source chip 3, because the image source chip 3 is an LCOS chip, the surface of the image source chip can reflect and emit projection light, the projection light is also linearly polarized light, the projection light passes through the first 1/4 wave plate here to form second circularly polarized light, and the rotation direction of the second circularly polarized light is opposite to the rotation direction of the first circularly polarized light by reasonably arranging the first 1/4 wave plate and the optical wave modulation device 12. The polarization holographic grating used in this embodiment reflects and diffracts the first circularly polarized light and transmits the second circularly polarized light, so that when the second circularly polarized light is incident on the optical waveguide 2 and is incident on the polarization holographic grating, the second circularly polarized light can be efficiently transmitted from the polarization holographic grating and is incident on the projection lens.

In this embodiment, the rotation directions of the first circularly polarized light and the second circularly polarized light refer to whether the two circularly polarized lights are left circularly polarized light or right circularly polarized light, and the first circularly polarized light and the second circularly polarized light are left circularly polarized light or right circularly polarized light, which is determined by the optical wave modulation device 12 and the first 1/4 wave plate; the rotation direction of the second circularly polarized light is opposite to that of the first circularly polarized light, namely, when the first circularly polarized light is left-circularly polarized light, the second circularly polarized light is right-circularly polarized light; on the contrary, when the first circularly polarized light is right circularly polarized light, the second circularly polarized light is left circularly polarized light. No matter which of the first circularly polarized light and the second circularly polarized light is left circularly polarized light and which is right circularly polarized light, it is only required to ensure that the coupling-out element 22, i.e. the polarization holographic grating, reflects and diffracts the first circularly polarized light and transmits the second circularly polarized light.

It should be noted that, in practical applications, the conversion of the projection light output from the image source chip 3 into the second circularly polarized light is not limited to be implemented by using the dimming device 5 such as the first 1/4 wave plate, for example, if the image source chip 3 uses an LCOS chip having a 1/2 wave plate function, the LCOS chip just satisfies that the phase difference between the reflected image light and the incident light is pi or an odd multiple thereof, the dimming device 5 is not required, and the projection light output by the LCOS chip itself is the second circularly polarized light.

The polarizer 121 and the second 1/4 wave plate 122 may be used for the light wave modulation device 12, and the included angle between the fast axis and the slow axis of the second 1/4 wave plate 122 and the polarization direction of the polarizer 121 is 45 degrees. Of course, this application does not exclude the use of other optical wave modulation means.

Therefore, through the light wave modulation device 12, the first 1/4 wave plate and the mutual cooperation between the polarization holographic grating of the second end of the optical waveguide 2, the separation of the effective projection light can be completed, and when the projection light is transmitted and emitted to the projection lens 4 through the second end of the optical waveguide 2 is avoided to a great extent, the coupling-out element 22 absorbs and reflects the projection light, the transmissivity of the coupling-out element 22 to the projection light is improved, the brightness of the projection light output by the projection light machine is further improved, and the display effect of the projection display device is ensured.

Further, the light source 10 of the projector light machine may generally adopt a laser light source or an LED light source. Light Emitting Diodes (LEDs) and laser light sources are primary color light sources, and have advantages of small optical expansion and good stability, in addition to color advantages, which greatly reduces the complexity of the subsequent illumination system of the light source 20, thereby achieving high integration and reducing the volume of the system, and being very suitable for being used as a light source of a micro projection display system.

However, when a laser light source is used, laser speckle exists in the light spot output by the light source 10, which may affect the imaging effect of the output projection light to some extent. For this purpose, in an alternative embodiment of the present application, a spot-eliminating device is further provided.

There are many different arrangements of the speckle removing device. For example, the speckle removing device can be an electrically controlled polarizer, and can comprise a TN liquid crystal cell and a speckle removing polarizer arranged on the surface of the TN liquid crystal cell, wherein the polarizer and the TN liquid crystal cell jointly form the electrically controlled polarizer.

When no external electric field is applied to the TN liquid crystal cell, the polarization direction of incident light is deflected by 90 degrees along with the twist direction of liquid crystal molecules in the process of passing through the liquid crystal layer; after a voltage is applied to the liquid crystal box and reaches a certain value, the long axes of the liquid crystal molecules are deflected along the direction of the electric field, and the polarization direction of the emergent light is not deflected. The polarizer can be controlled by a circuit to make random and rapid changes according to the Hadamard matrix arrangement rule. The polarization direction of the transmitted light is changed along with the change of the voltage applied on the liquid crystal box, the patterns at each moment meet Hadamard matrix distribution, Hadamard matrixes with the same size are orthogonal, and the coherence of the transmitted light at any moment approaches zero; the frequency of the electric field needs to exceed the resolution limit of human eyes by 60Hz, so that the human eyes cannot distinguish the change of the light field, and the effect of inhibiting or eliminating laser speckles can be achieved.

The speckle reduction polarizing plate in the speckle reduction device may be the same polarizing plate as the polarizing plate in the optical wave modulation device, or may be two different polarizing plates.

Optionally, the speckle removing device can also adopt an electric control PDLC panel. The PDLC panel is controlled by a circuit to make random and rapid changes according to the Hadamard matrix arrangement rule. The polarization direction of the transmitted light is changed along with the change of the voltage, patterns at each moment meet Hadamard matrix distribution, Hadamard matrixes with the same size are orthogonal, and the coherence of the transmitted light at any moment approaches zero; the frequency of the electric field needs to exceed the resolution limit of human eyes by 60Hz, so that the human eyes cannot distinguish the change of the light field, and the effect of inhibiting or eliminating laser speckles can be achieved.

The electrically controlled PDLC panel may be embedded in the first end of the optical waveguide 2, or the first end surface of the optical waveguide 2 may be disposed, so that the light beam output by the light source 10 is modulated into circularly polarized light by the light wave modulation device 12, and then coupled into the optical waveguide 2 through the electrically controlled PDLC panel.

In order to further improve the imaging effect of the projection light emitted by the projector, a beam expanding and collimating device 11 may be further disposed on the output light path of the light source 10. The beam expanding and collimating device 11 is disposed between the light source 10 and the light wave modulation device 12, and may include a beam expanding lens and a collimating lens. The light output from the light source 10 passes through the beam expanding lens and the collimating lens to form parallel light beams, and the parallel light beams are incident on the light wave modulation device 12.

The application also provides an embodiment of a projection display device, which comprises the projection light machine of the projection display device as described in any one of the above embodiments. The display equipment is arranged on the output light path of the projection light machine, and projection light output by the projection light machine is input into the display equipment, so that a user can watch the projection picture displayed on the display equipment.

For example, the projection display device may be AR display glasses with the projector engine disposed in the temple of the AR glasses. Because the appearance structure of projection ray apparatus more tends to the platyzing structure in this application, be favorable to adapting to the installation setting in the long and narrow mirror foot structure, avoid the too big user experience poor problem that leads to of mirror foot of AR glasses.

Of course, the projection display device in the present application does not exclude other kinds of projection display devices, and any projection display device including the projection light engine as described in any one of the above should be included in the protection scope of the present application.

It is noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Furthermore, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include elements inherent in the list. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element. In addition, parts of the above technical solutions provided in the embodiments of the present application, which are consistent with the implementation principles of corresponding technical solutions in the prior art, are not described in detail so as to avoid redundant description.

The above description of the embodiments is only intended to facilitate the understanding of the method of the invention and its core idea. It should be noted that, for those skilled in the art, it is possible to make various improvements and modifications to the present invention without departing from the principle of the present invention, and those improvements and modifications also fall within the scope of the claims of the present invention.

Claims

1. A projection optical machine of projection display equipment is characterized by comprising a light source part, an optical waveguide, an image source chip and a projection lens, wherein the first end of the optical waveguide is arranged on an output light path of the light source part;

2. The light engine for a projection display device according to claim 1, wherein the light source unit comprises a light source and a light wave modulation device disposed in an output light path of the light source;

the light wave modulation device is used for modulating the light output by the light source into first circularly polarized light;

3. The light engine of claim 2, wherein the image source chip is an LCOS chip; the dimming device is a first 1/4 wave plate.

4. The light engine of claim 2, wherein the light wave modulation device comprises a polarizer and a second 1/4 wave plate, and the fast and slow axes of the second 1/4 wave plate form an angle of 45 degrees with the polarization direction of the polarizer.

5. The projection optical engine of the projection display device according to claim 2, wherein the light source is a laser light source, and a speckle removing device is further disposed on an output optical path of the laser light source;

or the speckle removing device is an electric control PDLC panel.

6. The light engine of claim 5, wherein the PDLC panel is disposed adjacent to or embedded within the first end of the light guide.

7. The light engine of claim 2, wherein a beam expanding and collimating device is disposed between the light source and the light wave modulator.

8. The light engine for a projection display device of claim 2, wherein the coupling-in element is any one of a surface relief grating, a holographic grating, and a PVG grating.

9. A projection display device, characterized by a projection light engine comprising a projection display device according to any one of claims 1 to 8.

10. The projection display device of claim 9, wherein the projection display device is AR glasses.