WO2020228755A1

WO2020228755A1 - Laser projection apparatus

Info

Publication number: WO2020228755A1
Application number: PCT/CN2020/090129
Authority: WO
Inventors: 李晓平; 钟强; 阴亮
Original assignee: 青岛海信激光显示股份有限公司
Priority date: 2019-05-14
Filing date: 2020-05-14
Publication date: 2020-11-19
Also published as: CN111948886A

Abstract

A projection imaging apparatus, which relates to the technical field of imaging. The projection imaging apparatus comprises a light valve and a projection lens. The projection lens comprises a planar mirror group, a refractive lens group, and a curved mirror group. The planar mirror group comprises at least one mirror, and the planar mirror group is disposed between a portion of lenses of the refractive lens group and the curved mirror group. An image beam emitted by the light valve is transmitted through at least a portion of lenses of the refractive lens group, is then incident to the planar mirror group, is reflected at least once by the planar mirror group, and is then incident to the curved mirror group. The curved mirror group is used to reflect and image the image beam onto a screen. The projection imaging apparatus reflects light emitted by a light source by means of the mirrors and then changes the light path, and the optical axes of two mirror groups are not located on the same straight line, which reduces the length of the projection lens and solves the problem in the prior art of the length of projection devices being relatively long, thereby achieving the effect of reducing the length of the projection devices.

Description

Laser projection device

This application is required to be submitted to the Chinese Patent Office on May 14, 2019, with the application number of 201910398141.6, and the application name is "Projection Lens and Projection Imaging System", and on March 13, 2020, to the China Patent Office with the application number: 202010177890.9, The priority of the Chinese patent application named "Projection Lens and Projection Equipment", the entire content of which is incorporated in this application by reference.

Technical field

This application relates to the field of imaging technology, and in particular to a projection imaging device.

Background technique

A projection imaging device is a device that can project an image onto a screen.

At present, the projection imaging device usually includes: a light source, an optical machine, and a projection lens. The light source is used to provide illumination for the opto-mechanical part. The light source can be a monochromatic laser light source to excite the fluorescent wheel to generate three-color light, or it can be a three-color laser light source. The core component of the opto-mechanical part is a light valve, which is a light modulation element, and the light source emits The light beam passes through the illuminating light path of the light engine to form a beam conforming to the predetermined incident angle and shape, and then illuminates the surface of the light valve. In the DLP projection system, the light valve is a DMD digital micro-mirror array, and the DMD is a reflective light valve element. The light beam reflected by the DMD light valve is incident on the projection lens for imaging.

In the traditional telephoto projection system, the projection lens has a large volume. In the ultra-short-throw projection equipment, the projection lens is also an ultra-short-throw projection lens. Due to its small projection ratio, the ultra-short-throw projection lens has a relatively small beam confinement ability. Strong. When meeting the requirements of high resolution, the number of lenses is large and the volume is difficult to compress.

Limited by the resolution of the DMD, in order to achieve an effect higher than the resolution of the DMD itself, a galvanometer element is added to the optical path. The galvanometer is a flat piece of glass. Through high-frequency vibration, the beam can be dislocated and transmitted. Usually, the galvanometer It is set between the light valve and the projection lens, which requires the projection lens to have a sufficiently long back focus, which refers to the distance from the light exit surface of the DMD to the first lens of the projection lens to accommodate the lower galvanometer. The long back focus of the lens will increase the total length of the projection imaging device, and the lens must be able to accommodate light beams with different offset angles. The size reduction of the lens is very effective.

In the related art, the compression of the projection lens and the projection imaging device is very limited, and cannot meet the requirements of miniaturization and small volume.

Summary of the invention

The embodiment of the application provides a projection imaging device. The technical solution is as follows:

According to an aspect of the present application, there is provided a projection imaging device, the projection imaging device including a light valve and a projection lens, the projection lens including:

A plane mirror group, a refracting mirror group and a curved mirror group, the plane reflecting mirror group includes at least one reflecting mirror; the plane reflecting mirror group is arranged between a part of the refraction mirror group and the curved mirror group between,

The image light beam emitted by the light valve is transmitted through at least part of the lenses of the refracting mirror group, then enters the flat mirror group, and is reflected by the flat mirror group at least once, and then enters the curved mirror group; The curved mirror group is used to reflect and image the image beam on the screen.

Optionally, the plane mirror group includes a first mirror, the refraction mirror group includes a first refraction mirror group and a second refraction mirror group, the first refraction mirror group, the first mirror and the The second refracting lens group is arranged in sequence along the optical path direction of the projection lens.

Optionally, the flat mirror group includes a second mirror, and the second mirror is located between the refracting mirror group and the curved mirror group.

Optionally, the plane mirror group includes a first mirror and a second mirror, and the refraction mirror group includes a first refraction mirror group and a second refraction mirror group;

The first mirror is located between the first refraction mirror group and the second refraction mirror group, and the second mirror is located between the second refraction mirror group and the curved mirror group.

Optionally, the direction of the image beam emitted to the first reflector is parallel to the direction of the image beam emitted from the second reflector.

Optionally, the first reflector is a reflective galvanometer.

Optionally, the second reflector is a reflective galvanometer.

Optionally, the second reflector is located on the imaging surface of the refractive lens group.

Optionally, the projection imaging device further includes a transmissive galvanometer, and the transmissive galvanometer is located in the refractive lens group.

Optionally, the transmissive galvanometer includes an optical lens and a driving component;

The driving component is used to drive the optical lens to swing at a specified angle according to a target frequency.

Optionally, the specified angle is negatively related to the incident angle of the image beam on the light incident surface of the optical lens.

Optionally, the incident angle is less than 16°.

Optionally, the projection lens further includes a galvanometer, the galvanometer is located on the side of the first refraction lens group away from the first reflector, and is used to receive the light emitted by the light valve and transfer the light Directed toward the first refracting lens group.

The beneficial effects brought by the technical solutions provided by the embodiments of the present application include at least:

A projection imaging device is provided, including a light valve and a projection lens. The projection lens includes a flat mirror group, a refracting mirror group, and a curved mirror group. The flat mirror group is arranged on part of the refractive mirror group and the curved mirror group. Among them, the plane mirror group includes at least one mirror, the image beam emitted by the light valve is transmitted through at least part of the refractive lens group, and then enters the plane mirror group, and the curved mirror group reflects the image light beam and forms an image on the screen. on. In the present application, a reflecting mirror is arranged between the mirror groups, and the light source route is changed after reflecting the light source, so that the optical axes of the two mirror groups are not on the same straight line, so that the length of the projection lens along the main optical axis direction can be shortened. The problem of long length of the projection imaging device in the related art is solved, and the effect of reducing the length of the projection imaging device is achieved. At the same time, the distance from the light valve to the lens can be shortened, and the light collection requirement of the first lens element of the lens is reduced, which also helps reduce the difficulty of lens design.

Description of the drawings

In order to more clearly describe the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings needed in the description of the embodiments. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained from these drawings without creative work.

FIG. 1 is a schematic structural diagram of a projection imaging device in related technologies provided by an embodiment of the present application;

2 is a schematic structural diagram of a projection imaging device provided by an embodiment of the present application;

FIG. 3 is a schematic structural diagram of a projection imaging device provided by an embodiment of the present application;

4 is a schematic structural diagram of another projection imaging device provided by an embodiment of the present application;

5 is a schematic structural diagram of another projection imaging device provided by an embodiment of the present application;

FIG. 6 is a schematic diagram of a specific structure of the projection lens in FIG. 5;

7 is a schematic diagram of the structure of a reflective galvanometer in an embodiment of the application;

8 is a schematic diagram of the three-dimensional structure of the reflective galvanometer shown in FIG. 7;

9 is a schematic structural diagram of another projection imaging device provided by an embodiment of the application;

FIG. 10 is a schematic structural diagram of a lens group in a projection lens provided by an embodiment of the application;

11 is a schematic structural diagram of a projection imaging device provided by an embodiment of the application;

Fig. 12 is a modulation transfer function diagram of the projection device shown in Fig. 11;

Fig. 13 is a system field curvature and distortion diagram of the projection device shown in Fig. 11;

14 is a schematic diagram of a scene in which a transmissive galvanometer performs offset processing on an image beam according to an embodiment of the present application;

FIG. 15 is a schematic diagram of a scene in which another transmission galvanometer performs offset processing on an image beam according to an embodiment of the present application;

FIG. 16 is a schematic diagram of a scene in which another transmission galvanometer performs offset processing on an image beam according to an embodiment of the present application;

FIG. 17 is a schematic structural diagram of another projection imaging device provided by an embodiment of the present application;

FIG. 18 is a schematic structural diagram of another projection imaging device provided by an embodiment of the present application;

19 is a schematic structural diagram of a projection imaging device provided by an embodiment of the present application;

FIG. 20 is a schematic structural diagram of another projection imaging device provided by an embodiment of the present application.

Through the above drawings, the specific embodiments of the present application have been shown, which will be described in more detail below. These drawings and text description are not intended to limit the scope of the concept of the present application in any way, but to explain the concept of the present application to those skilled in the art by referring to specific embodiments.

Detailed ways

In order to make the objectives, technical solutions, and advantages of the present application clearer, the following will further describe the embodiments of the present application in detail with reference to the accompanying drawings.

FIG. 1 is a schematic structural diagram of a projection imaging device in the related art. The projection imaging device 10 includes a light valve 11, a total reflection prism 12, a galvanometer 13, a refractive lens group 14 and a reflecting mirror group 15. The refracting lens group 14 includes a first lens group 141, a second lens group 142, and a third lens group 143 arranged in sequence along the length direction 10 of the optical axis. The light emitted by the light source passes through the light valve 11 and the total reflection prism 12 and then is directed to the galvanometer 13, the light transmitted through the galvanometer 13 is directed to the refracting lens group 14 through the vibration of the galvanometer 13, and the light source passes through the first mirror group 141 in turn , The second mirror group 142 and the third mirror group 143 are then directed by the mirror group 15 to the outside screen to form an imaging picture.

However, since the first lens group 141, the second lens group 142, and the third lens group 143 in the projection imaging device are arranged in order along the length of the optical axis, the design difficulty of the projection imaging device is increased.

FIG. 2 is a schematic structural diagram of a projection imaging device shown in an embodiment of the present application. The projection imaging device 30 may include a light valve 31 and a projection lens 20. The projection lens 20 may include a flat mirror group 22, a refracting mirror group 21, and a curved mirror group 23. The flat mirror group 22 includes at least one mirror; The mirror group 22 is arranged between a part of the refractive lens group 21 and the curved mirror group 23,

The image light beam 40 emitted by the light valve 31 is transmitted through at least part of the lenses of the refracting mirror group 21, and then enters the plane mirror group 22, and is reflected by the plane mirror group 22 at least once, and then enters the curved mirror group 23. 23 is used to reflect and image the image beam 40 on the screen 32.

In summary, an embodiment of the present application provides a projection imaging device, including a light valve and a projection lens. The projection lens includes a flat mirror group, a refracting mirror group, and a curved mirror group. The flat mirror group is arranged in the refraction mirror group. Between the part of the mirror and the curved mirror group, the flat mirror group includes at least one mirror. The image light beam emitted by the light valve is transmitted by at least part of the refraction mirror group and enters the flat mirror group, and then the curved mirror group The image beam is reflected and imaged on the screen. In the present application, a reflecting mirror is arranged between the mirror groups, and the light source route is changed after reflecting the light source, so that the optical axes of the two mirror groups are not on the same straight line, so that the length of the projection lens along the main optical axis direction can be shortened. The problem of long length of the projection imaging device in the related art is solved, and the effect of reducing the length of the projection imaging device is achieved. At the same time, the distance from the light valve to the lens can be shortened, and the light collection requirement of the first lens element of the lens is reduced, which also helps reduce the difficulty of lens design.

Please refer to FIG. 3, which shows a schematic structural diagram of another projection imaging device provided by an embodiment of the present application.

Optionally, the plane mirror group includes a first mirror 221, the refraction mirror group includes a first refraction mirror group 211 and a second refraction mirror group 212, the first refraction mirror group 211, the first mirror 221, and the second refraction mirror The groups 212 are sequentially arranged along the optical path direction of the projection lens.

Fig. 4 shows a schematic structural diagram of another projection lens provided by an embodiment of the present application.

Optionally, the plane mirror group includes a second mirror 222, and the second mirror 222 is located between the refracting mirror group and the curved mirror group 23.

FIG. 5 shows a schematic structural diagram of another projection lens provided by an embodiment of the present application.

Optionally, the plane mirror group includes a first mirror 221 and a second mirror 222, and the refraction mirror group includes a first refraction mirror group 211 and a second refraction mirror group 212;

The first reflecting mirror 221 is located between the first refracting lens group 211 and the second refracting lens group 212, and the second reflecting mirror 222 is located between the second refracting lens group 212 and the curved mirror group 23. FIG. 6 is a schematic diagram of a specific structure of the projection lens in FIG. 5. The refractive lens group may include a plurality of lenses.

Optionally, the direction of the image beam 40 emitted to the first mirror 221 is parallel to the direction of the image beam emitted from the second mirror 222.

Optionally, the first reflecting mirror 221 is a reflective galvanometer. When the first reflecting mirror 221 is a reflective galvanometer, the function of improving the resolution of the galvanometer can be achieved while changing the optical path, which can replace the above-mentioned related technology, as shown in FIG. 1 in the total reflection prism 12 and the first The plate glass galvanometer 13 between the lens groups 141 can therefore eliminate the plate glass galvanometer lens provided between the light valve and the first lens group, thereby shortening the length of the projection lens along the optical axis and reducing the cost of the projection device Design difficulty.

Optionally, the second reflector 222 is a reflective galvanometer. The second reflecting mirror 222 may also be a reflecting galvanometer. The reflector in the projection lens can have a variety of configurations. For example, the first configuration is that the first reflector 221 and the second reflector 222 can both be reflective galvanometers; for 2k to 4k, it needs to be rotated around two Two rotating shafts can rotate, and two galvanometers can be rotated around one rotating shaft respectively, but for 3k to 4k, only one rotating shaft needs to be rotated, so only one galvanometer is needed. The second configuration is that the first mirror 221 is a reflective galvanometer and the second mirror 222 is a plane mirror; the third configuration is that the first mirror 221 is a plane mirror, and the second mirror 222 is a reflective mirror. Galvanometer. The specific configuration method is not limited herein in the embodiment of the application.

Optionally, the second reflector is located on the imaging surface of the refractive lens group. When the reflecting mirror is located on the imaging surface of the refracting lens group, the reflecting mirror will not affect the imaging of the refracting lens group, thereby not affecting the imaging effect.

FIG. 7 is a schematic diagram of the structure of a reflective galvanometer in an embodiment of the application, and the description is made by taking the first reflective mirror 221 as a reflective galvanometer in FIG. 5 as an example.

Optionally, the reflective galvanometer 221 includes a vibrator base 2211, a mirror 2212, a metal supporting plate 2213, and at least one vibrating component 2214 on the vibrator base 2211, and each vibrating component 2214 includes an abutting portion 2215 , Vibrator 2216 and spring sheet 2217; the reflector 2212 is located on the metal bearing plate 2213, the metal bearing plate 2213 is connected to the spring plate 2217, and the spring plate 2217 is installed on the vibrator base 2211 and abuts against the abutment portion 2215 Above, the leaf spring 2217 has a target load.

The vibrator 2216 can provide a power source for the reflective galvanometer 222. After the vibrator 2216 is turned on, the vibrator 2216 moves up and down to generate power, which drives the spring sheet 2217 connected to the vibrator 2216 to load it. The spring sheet 2217 and the vibrator base The gap between the seats 2211 sets the load by bending the spring sheet 2217 in place. Since the abutting portion 2215 is connected to the spring sheet 2217, the load of the spring sheet 2217 makes the metal bearing plate 2213 abut against the vibrator base 2211, Thus, the rotation shaft abutting portion 2215 is formed. The vibrator 2216 is connected to the metal supporting plate 2213 to provide a force to tilt the reflector 2212. Therefore, when the supporting portion 2215 rotates, the metal supporting plate 2213 is driven to rotate, and the reflector 2212 occurs according to the rotation of the metal supporting plate 2213. Offset to achieve the deflection of the light source to achieve the function of a galvanometer, and the reflector 2212 can reflect light, refract the light source from the original optical axis route, thereby changing the path of the light source, so that the second refraction mirror group 212 can follow The position of the reflected light source is fixed and does not need to be arranged in sequence along the length of the optical axis, which reduces the length of the projection lens in the length direction of the optical axis of the first lens group. The vibrator 2216 may include coils, piezoelectric ceramics, etc., or may be other vibrators, which are not limited in the embodiment of the present application.

FIG. 8 is a schematic diagram of the three-dimensional structure of the reflective galvanometer shown in FIG. 7. One end of the metal supporting plate 2213 is connected to the vibrator base 2211, and the other end of the metal supporting plate 2213 is connected to the reflector 2212. The metal supporting plate 2213 can drive the supporting portion 2215 while supporting and fixing the reflector 2212. The rotation of is transmitted to the reflecting mirror 2212, so that the reflecting mirror 2212 can be deflected according to the rotation of the abutting portion 2215.

In addition, the time required for the mirror 2212 to deflect once can be set according to the requirements for imaging pixels in the projection device. For example, when the configuration of the projection device requires 3K pixel resolution plus a galvanometer, the mirror deflects once. The time required is 2 times the frame rate of the input image. When the configuration of the projection device requires a 3K pixel resolution plus a galvanometer, the time required for the mirror to deflect once is 4 times the frame rate of the input image. The specific position of the reflective galvanometer can meet the conditions: the magnification of the subsequent light path of the mirror to the screen remains the same in each field of view, and the angle of incidence of each field of view on the mirror approaches the same.

Optionally, the flatness of the reflector is less than 3 fringes, and the irregularity is less than 1/2 fringe. Flatness refers to the deviation of the height of the macroscopic unevenness of the substrate from the ideal plane. Compare the measured actual surface with the ideal plane, the line value distance between the two is the flatness error value; or by measuring the relative height difference of several points on the actual surface, and then convert the flatness error value expressed by the line value . The method for measuring the flatness error can refer to related technologies, and the embodiments of the present application are not limited herein. The flatness of the mirror used in this application is less than 3 stripes, and the irregularity is less than 1/2 stripes. The specific flatness is not limited in the embodiment of the present application.

Optionally, the reflective galvanometer includes two vibration components, and the abutting parts of the two vibration components are vertical. Exemplarily, the direction of rotation of the abutment portion of one of the vibration components is left and right rotation with the optical axis as the axis, and the rotation direction of the abutment portion of the other vibration component is rotation up and down with the optical axis as the axis, because the abutment portion can drive The vibrator base 2211 rotates, the vibrator base 2211 can drive the metal bearing plate 2213 to rotate, and the metal bearing plate 2213 can drive the reflector 2212 to deflect. Therefore, when the abutment portion rotates left and right, the vibrator base 2211 drives the metal bearing The supporting plate 2213 rotates left and right, the metal supporting plate 2213 drives the mirror 2212 to deflect left and right. When the supporting part rotates up and down, the vibrator base 2211 drives the metal supporting plate 2213 to rotate up and down, and the metal supporting plate 2213 drives the reflecting mirror 2212 up and down. Deflection, that is, when the rotation directions of the abutting parts of the two vibrating components are perpendicular, the deflecting direction of the reflector 2212 can be increased, thereby increasing the direction of pixel shifting, and achieving the effect of improving resolution.

FIG. 9 is a schematic structural diagram of another projection lens provided by an embodiment of the application.

Optionally, the projection lens further includes a galvanometer 26, which is located on the side of the first refraction lens group 211 away from the first reflector 221, and is used to receive the light emitted by the light valve and direct the light toward the first refraction mirror. Group 211. The galvanometer 26 vibrates at a fixed angle and a fixed direction through a vibrating circuit to realize the offset of the imaging beam, thereby improving the resolution of the projection device. The light source emitted by the light valve enters the galvanometer 26, and the galvanometer 26 projects the light source offset by the galvanometer into the first mirror group 211. At this time, the first mirror 221 and the second mirror 222 may be flat mirrors. Used to fold the light path. In the embodiment of the present application, the galvanometer 26 is flat glass.

Optionally, the first refracting lens group 211 can move along the optical axis of the first refracting lens group 211. FIG. 10 is a schematic structural diagram of a lens group in a projection lens provided by an embodiment of the application. FIG. 10 includes a first refracting lens group 211, a second refracting lens group 212, and a curved mirror group 23. The first refracting lens group 211, the second refracting lens group 212 and the curved mirror group 23 are all located on different planes. The first refracting lens group 211 in FIG. 10 includes a first lens group and a second lens group. The first lens group includes 6 lenses, including 1 aspherical lens a2, 1 triplet lens a3, and 1 double lens group. Glue lens a6 and 3 spherical lenses a1, a4, a4. The second lens group includes a spherical lens a7. Among them, the triple cemented lens a3 includes lenses a31, a32 and a33, and the double cemented lens a6 includes a61 and a62. Among them, the refractive powers of a1, a2, a31, a4, and a5 are all positive, and the refractive powers of a32, a33, a61, and a62 are negative.

The a2 lens is an aspheric lens, used to correct the astigmatism and coma of the imaging system, and can reduce the pressure of aberration correction of the subsequent lens. A2 lenses can be made of materials with lower refractive index and low melting point, such as L-BSL7, D-K59, L-BAL42 (L-BSL7, D-K59, and L-BAL42 are three types of optical materials) to achieve Lower cost non-curved surface processing and manufacturing. The specific model selection is not limited in the embodiment of this application.

The a3 lens is a triple cemented lens, which is used to correct the primary aberrations of the system such as spherical aberration, field curvature, and chromatic aberration. The a3 lens is immediately after the aspheric lens a2, which can control the aberration of the system to the greatest extent. The a3 lens can be matched with materials with a large difference in Abbe number. The Abbe number or dispersion coefficient Vd of the middle lens can be selected to be less than 35, and the refractive index can be higher. Usually nd>1.8, the lenses on both sides can be selected For materials with small refractive index and large Abbe number, the nd value should be around 1.45 to 1.60, and the Abbe number or dispersion coefficient should be between 65 and 95.

The a4 and a5 lenses bear greater power, and the diaphragm is located in the a4 lens, which is beneficial to correct aberrations and control the system aperture. The a5 lens is more sensitive than the a4 lens. The a6 lens is a double cemented lens, used to correct spherical aberration and chromatic aberration, and the a6 lens can choose glass with a small difference in Abbe number to compensate for the chromatic aberration produced by the a4 and a5 lenses.

The lenses in the first refracting lens group 211 are all glass lenses, which can prevent the problem of deterioration of image quality caused by thermal deformation, and the lenses in the first refracting lens group are all positive. The movement of the first mirror group along the optical axis of the first refractor group can first compensate the imaging system tolerance to ensure the imaging quality of the system; the second mirror group moves along the optical axis of the first refractor group and moves in accordance with the position of the mirror The image quality can be adjusted in different sizes.

The second refracting lens group 212 may include 3 lenses, a8 lens and a9 lens are glass spherical lenses, a10 is a plastic aspheric lens, a8 lens has a positive refractive power, and a9 and a10 lens has a negative refractive power. Since the a10 lens is farther from the diaphragm and has a larger field of view, adding aspherical surface can greatly reduce system distortion and better correct astigmatism, so the second refractor group can cooperate with the mirror to correct the distortion. In addition, the curved mirror group 23 may include a curved mirror a11, and the curved mirror a11 may be a concave even-order aspheric mirror. That is, the concave surface of the curved mirror in the embodiment of the present application adopts an even aspheric design, or it may be a free-form curved reflector, which is not limited in the embodiment of the present application.

Optionally, the included angle between the optical axis of the first refracting lens group 211 and the optical axis of the second refracting lens group 212 is between 70 degrees and 110 degrees. The included angle includes two parts, a fixed turning angle and a vibration angle. The first part is a fixed turning angle to realize the turning of the light path. Its size is related to the requirements of the turning direction of the light path. The second part is the vibration angle, which is used to improve the resolution of the system. Its size is related to the magnification of the second lens group and the size of the pixel movement. It is characterized by high-frequency rotation, and the angle is generally small. The rotation frequency is related to the image frame rate. Related, the rotation in one direction is 2 times the image frame rate, and the rotation in two directions is 4 times the image frame rate. The vibration angle requirement is that the two indicators of the incident angle of each field of view on the first reflector 221 and the magnification of the optical system between the reflector and the screen cooperate with each other, and the pixel deviation of each field of view point does not exceed 10% of the reference value. It can meet the requirements of the pixel deflection tolerance at the screen end without affecting the display effect. In the embodiment of the present application, the angle between the optical axis of the first refracting lens group 211 and the optical axis of the second refracting lens group 212 is 90 degrees. The specific number of angles can be slightly adjusted according to the design of the projection lens, which is not limited in the embodiment of the present application.

FIG. 11 is a schematic structural diagram of a projection device provided by an embodiment of the application.

Optionally, an embodiment of the present application further provides a projection device 30, which includes a light valve 31 and the projection lens 20 in the foregoing embodiment. The light valve 31 can provide a light source for the projection lens 20. The light valve (English: digital micromirror device, DMD for short) is a digital micromirror element. The light valve can be 2K resolution or 3K resolution. The 2K resolution light valve can also reach 4K when used with the galvanometer. Resolution. The reflective galvanometer needs to rotate around two rotation axes. The 3k resolution light valve can also be used in conjunction with the galvanometer to achieve 4k resolution. At this time, it needs to rotate around a rotation axis. The light valve is controlled by the control circuit to reflect the light source incident on the light valve to the projection lens 20. An imaging beam is generated, and the image projected on the screen by the imaging beam is the final image.

Optionally, the projection device 30 further includes a total reflection prism 33, which may be located between the light valve 31 and the first refraction lens group 211 of the projection lens 20, or when the projection device includes a flat galvanometer 26, the total reflection The prism 33 may be located between the light valve 31 and the flat galvanometer 26. The total reflection prism 33 includes two cemented total reflection prisms with a cementing gap of 3-8 microns. When the total reflection prism 33 is used for illumination, the total reflection function is realized in the illumination light path, and the light incident on the prism The light is totally reflected to the light valve; when the total reflection prism 33 is used in an ultra-short focal lens system, the total reflection prism 33 can be used as a flat glass to well control the influence of dust on the imaging quality of the system. The total reflection prism reduces the number of ordinary mirrors used and can reduce the system volume.

Fig. 12 is a modulation transfer function diagram of the projection device shown in Fig. 11, the ordinate in Fig. 12 is the modulation transfer function value, the abscissa is the spatial frequency (unit: millimeter), and TS represents the meridian and sagittal directions respectively.

Fig. 13 is a system field curvature and distortion diagram of the projection device shown in Fig. 11, the left picture in Fig. 13 is a system field curvature diagram, and the abscissa is the field curvature (unit: mm). The picture on the right is the system distortion diagram, and the abscissa is the deformation rate (%).

It can be seen from the above drawings that the projection lens and the optical system in the projection device in the embodiments of the present application meet the following conditions: the system is a rotationally symmetric system. Back focus length: the physical distance from the light valve to the last lens of the lens is 29.203mm. Throw ratio is 0.25, relative aperture F# is 2.0, system total length is 202.7mm, telecentricity is 0.284°, |FB/F|=1.687, |FS/F|=6.58, |FT/F|=5.39, |FM /F|=1.99, where F is the equivalent focal length of the refractive lens group, FB is the equivalent focal length of the first lens group, FS is the equivalent focal length of the second lens group, and FT is the equivalent focal length of the third lens group, FM is the equivalent focal length of the mirror. |L2/L1|≤0.385, where L1 is the length of the refracting lens group (between the first refracting lens group and the second reflecting mirror), and the L2 is (between the first refracting lens group and the second reflecting mirror) and The spacing between the curved mirror groups. Entrance pupil diameter |d|≤0.192, L2 variation range meets |△L2|≤0.8mm, the offset of the light valve pixel surface of the ultra-short focal lens system relative to the optical axis (the offset is the light valve pixel surface relative to the light axis Axis offset, English: offset) satisfies the relational expression: 142%<offset<148%. The projection range is 60 to 100 inches.

In the embodiment of this application, when the image beam incident on the galvanometer is a parallel beam (that is, the incident angle of each light in the image beam is the same), after the optical lens in the galvanometer swings from one position to another, The displacement distance of each pixel of the projection image corresponding to the image beam is equal, so that the offset of each field of view in the projection lens to the projection screen is consistent, which can ensure the high-resolution display of the visual image. Among them, the offset of the field of view refers to the actual displacement distance of the field of view. In the embodiment of the present application, since the galvanometer is placed in the projection lens, the angles of the image beams incident on the galvanometer in each field of view are different, so that the offset of each field of view to the projection screen is different. The position of the galvanometer in the projection lens can be set so that the incident angle of the image beam on the light incident surface of the optical lens is smaller than the specified angle threshold, so that when the optical lens swings, the difference between different pixels in the projected image corresponding to the image beam The deviation of the shift distance is small, and the offset of each field of view in the projection lens is within the tolerance range, which meets the high-resolution display requirements of the visual image.

In the embodiment of the present application, the specified angle of the swing of the optical lens of the galvanometer is also related to the magnification of the part of the projection lens between the galvanometer and the light valve, that is, it is related to the position of the galvanometer in the projection lens.

In the embodiment of the present application, the process of determining the specified angle of the swing of the optical lens in the galvanometer and the setting position of the galvanometer in the projection lens includes: setting the galvanometer in the projection lens where the image beam is close to the parallel beam ; Calculate the specified angle of the optical lens swing in the galvanometer based on the specific light in the image beam; calculate the predicted displacement distance of the pixels of the projection image corresponding to the image beam according to the specified angle; when the absolute value of the predicted displacement distance is in the target When the shift distance is within the shift tolerance range, it is determined that the position can be used to set the galvanometer. Wherein, the above-mentioned specific light may be the chief light of the near-center field of view (referring to the field of view transmitted along the optical axis), and the target displacement distance is determined by the pixel size of the light valve.

Illustratively, FIGS. 14 and 15 are respectively schematic diagrams of scenes in which a transmissive galvanometer provided in an embodiment of the present application performs offset processing on an image beam. As shown in Figure 14 and Figure 15, the specified angle of the optical lens swing in the galvanometer is θ, and the thickness of the optical lens is D. Assuming that the refractive index of the optical lens is n, the magnification of the part of the projection lens between the galvanometer and the projection screen is β, the magnification of the projection lens is β0, and the transmission direction of the specific light incident on the optical lens is the same as that of the projection lens. The included angle of the optical axis direction is γ as an example, and the process of determining the specified angle of the swing of the optical lens in the galvanometer and the setting position of the galvanometer in the projection lens will be described.

The first step is to calculate the specified angle of swing of the optical lens in the galvanometer according to the specific light in the image beam.

When the optical lens swings to the first position (the position indicated by the solid line in Figure 14), the incident angle of the specific light on the optical lens is γ, and the refraction angle

The displacement of the specific light after passing through the optical lens is h0=D×tan I0. When the optical lens swings to the second position (the position indicated by the dotted line in Figure 14), the incident angle of the specific light on the optical lens is γ+θ, and the refraction angle

Correspondingly, the displacement of the specific light after passing through the optical lens

Wherein, the displacement of the specific light ray refers to the distance between the incident position of the specific light ray on the optical lens and the exit position of the specific light ray on the optical lens on a plane perpendicular to the optical axis of the projection lens.

Therefore, when the optical lens swings from the first position to the second position, the actual displacement distance h0-h1 of the specific light beam on the optical lens. Since the image beam emitted from the optical lens is enlarged by β times and then enters the projection screen, the actual displacement distance of the pixel corresponding to the specific light in the image beam at the screen end (that is, on the projection screen) is (h0 -h1)×β. Assuming that the pixel size of the light valve is 5.4μm, and the target displacement distance of the pixel of the projected image at the light valve end is 2.7μm, the actual displacement distance of the pixel at the screen end meets the target displacement distance, that is, (h0-h1 )×β=2.7×10 ^-3 ×β0mm. Since the refractive index n of the optical lens in the galvanometer, the thickness D of the optical lens, the magnification β of the part of the projection lens between the galvanometer and the projection screen, and the magnification β0 of the projection lens are all known values, it can be based on the above The formula calculates the specified angle θ of the optical lens swing.

The second step is to calculate the predicted displacement distance of the pixel of the projected image corresponding to the image beam according to the specified angle.

For example, suppose that the maximum incident angle of the light in the image beam on the optical lens is q. When the optical lens swings to the first position (the position indicated by the solid line in Figure 15), the refraction angle of the light beam with the largest incident angle q in the image beam incident on the optical lens on the optical lens

After the light passes through the optical lens, its displacement h2=D×tan Q. When the optical lens swings to the second position (the dotted line in Figure 15 indicates the position), the incident angle of the light on the optical lens q1=q+θ, the angle of refraction

Correspondingly, the displacement of the light after passing through the optical lens

Therefore, when the optical lens swings from the first position to the second position, the predicted displacement distance of the light on the optical lens is h4=h2-h3. Since the image beam emitted from the optical lens is enlarged by β times and then enters the projection screen, Therefore, the predicted displacement distance of the pixel corresponding to the light in the image beam at the screen end is h4×β.

Since the optical lens has a deflection angle tolerance when it swings, the deflection angle tolerance will cause the actual displacement distance of the light to be greater than the predicted displacement distance. Therefore, in practical applications, it is necessary to consider the influence of the deflection angle tolerance of the optical lens on the displacement distance of the light. FIG. 16 is a schematic diagram of a scene in which another galvanometer performs offset processing on an image beam according to an embodiment of the present application. As shown in Figure 16, the deflection angle tolerance of the optical lens in the galvanometer is α. For example, |α|≤0.05°, for example, α=0.03°.

Considering the tolerance of the deflection angle of the optical lens, when the optical lens swings to the second position (schematic position A in Fig. 16), the incident angle of the light corresponding to the maximum incident angle on the optical lens in the image beam is q2 =q+θ+α, refraction angle

Therefore, when the optical lens swings from the first position (the position indicated by the solid line in Figure 16) to the second position, the predicted displacement distance of the light beam on the optical lens is h6=h3-h5, because the image beam emitted from the optical lens is After being enlarged by β times, it is incident on the projection screen. Therefore, the predicted displacement distance of the pixel corresponding to the light in the image beam at the screen end is h6×β.

In the third step, when the absolute value of the predicted displacement distance is within the displacement tolerance range of the target displacement distance, it is determined that the position can be used to set the galvanometer.

After the predicted shift distance of the pixel at the screen end is calculated, the relationship between the absolute value of the predicted shift distance and the shift tolerance range of the target shift distance can be determined. When the absolute value of the predicted shift distance is within the shift tolerance range of the target shift distance, determine the position can be used to set the galvanometer, when the absolute value of the predicted shift distance is not within the shift tolerance range of the target shift distance , Change the setting position of the galvanometer and repeat the above steps until the position that can be used to set the galvanometer is determined.

For example, when the shift tolerance range of the target shift distance is (2.7×10 ^-3 ×β0)-g to (2.7×10 ^-3 ×β0)+g, considering the deflection angle tolerance of the optical lens, when 2.7× When 10 ^-3 ×β0≤|h4×β+h6×β|≤(2.7×10 ^-3 ×β0)+g, confirm that the position can be used to set the galvanometer; when 2.7×10 ^-3 ×β0＜|h4× β+h6×β|, or |h4×β+h6×β|>(2.7×10 ^-3 ×β0)+g, change the setting position of the galvanometer and repeat the above steps.

In the embodiment of this application, after determining the position that can be used to set the galvanometer, you can continue to determine other positions where the galvanometer can be set by the above method, and compare the predicted displacement distance corresponding to all the positions where the galvanometer can be set with the target displacement The difference of the distance, the position with the smallest difference is determined as the setting position of the galvanometer.

Optionally, in the embodiment of the present application, an optical lens with a certain thickness may be selected according to the position of the galvanometer in the projection lens. Usually the thickness of the optical lens is D≤3mm. The transmittance of the optical lens is ≥97%.

It can be seen from the above displacement distance formula that when the incident light of the optical lens in the galvanometer is constant, the greater the deflection angle θ, the greater the predicted displacement distance of the light on the optical lens, and the corresponding pixel corresponding to the light The greater the shift distance of the screen end. Optionally, the incident angle of the image beam in the projection lens on the light incident surface of the optical lens of the galvanometer lens may be less than 16°. In this way, affected by the tolerance of the deflection angle, when the actual maximum deflection angle of the optical lens is slightly larger than the theoretical maximum deflection angle, and the image beam output from the optical lens tends to be parallel, the shift distance of the pixel at the end of the screen is at the target shift Within the tolerance range of the bit distance.

Optionally, FIG. 17 is a schematic structural diagram of another projection imaging device 30 provided by an embodiment of the present application. As shown in FIG. 17, the light valve 31 shoots the image beam toward the refracting lens group 202. The refracting lens group 202 includes a first lens group 2021, a relay lens group 2022, and a second lens group 2021, which are sequentially arranged along the direction in which the image beam is incident and transmitted. Lens group 2023. The plane mirror group includes a first mirror 2041 and a second mirror 2042. The first mirror is located between the relay lens group 2022 and the second lens group 2023, and the second mirror 2042 is located between the second lens group 2023 and the curved reflector. Between the mirror groups, the transmissive galvanometer 201 is located between the first reflecting mirror 2041 and the second lens group 2023.

It should be noted that in the refraction lens group of the conventionally designed projection lens, there is a gap between the relay lens group and the second lens group, and the galvanometer lens is arranged in the gap without changing the relative positional relationship of each lens in the projection lens. , That is, there is no need to redesign the structure of the projection lens, which is highly feasible.

For example, referring to FIG. 17, when the transmissive galvanometer is located between the relay lens group 2022 and the second lens group 2023, the specified angle of the optical lens in the galvanometer 201 is 1°.

It should be noted that in the optical design of a lens, a unit composed of multiple lenses is usually regarded as a group, which can be intuitively moved as a unit as a whole. For example, there are a total of 10 lenses in the lens, and 5 lenses. The group is divided into two groups. Each of these two groups as a small whole can be displaced relative to each other. The displacement here can be the tolerance adjustment during assembly, or it can be matched with the lens zoom to achieve the difference between the groups. The distance changes while changing the focal length of the lens. The relative position of the lenses within each group does not change, and each group has its own focal length parameter.

Illustratively, the first lens group, the relay lens group, and the second lens group can be divided into three groups. According to the positions of the three groups in the projection lens, the first lens group can be called the rear group group, the relay lens group is called the middle group group, and the second lens group is called the front group group. Alternatively, the relay lens group and the second lens group may be divided into one group, and the embodiment of the present application does not limit the group division manner of the lens group.

Optionally, the first lens group may include: a plurality of lenses sequentially arranged along the direction in which the image light beam is incident and transmitted. For example, referring to FIG. 17, the first lens group 2021 may include nine lenses arranged in sequence along the direction in which the image beam is incident and transmitted, including: a first lens c1, a second lens c2, a third lens c3, and a fourth lens c4. , Fifth lens c5, sixth lens c6, seventh lens c7, eighth lens c8 and ninth lens c9.

Optionally, the relay lens group may include one or more relay lenses. The relay lens has the characteristics of a positive lens, that is, it has the ability to condense light. For example, the relay lens may be a positive power lens.

Optionally, the second lens group may include: a plurality of lenses sequentially arranged along the direction in which the image light beam is incident and transmitted. For example, referring to FIG. 17, the second lens group 2023 may include three lenses arranged in sequence along the direction in which the image beam is incident and transmitted, including: a tenth lens b1, an eleventh lens b2, and a twelfth lens b3. The second lens group can be used to correct the distortion of the projection lens.

Optionally, please continue to refer to FIG. 17, the refractive lens group 202 further includes a diaphragm 2024, and the diaphragm 2024 is located in the first lens group 2021. For example, the stop 2024 may be located between the fifth lens c5 and the sixth lens c6.

It should be noted that by disposing the galvanometer between the relay lens group and the second lens group, and disposing the diaphragm in the first lens group, the galvanometer can be arranged away from the diaphragm. When the incident angle of the image incident on the light incident surface of the optical lens is large, after the galvanometer performs the offset processing on the image beam, it will cause the shift distance deviation between the different pixels of the projected image corresponding to the image beam Larger, affect the projection imaging effect of the projection lens. The divergence angle of the image beam near the diaphragm is usually larger. Therefore, the galvanometer is usually set far away from the diaphragm, so that the shift distance between different pixels of the projection image corresponding to the image beam after the galvanometer shift processing is relatively large. Small, to ensure the projection imaging effect of the projection lens, and then realize the high-resolution display of the visual image.

Optionally, the galvanometer can also be arranged at other positions far away from the aperture. For example, the transmissive galvanometer 201 can also be arranged between the curved mirror group 203 and the refractor group 202, or, FIG. 18 is an example of the present application. For a schematic structural diagram of another projection lens, please refer to FIG. 18. The transmissive galvanometer 201 may also be disposed in the second lens group 2023, which is not limited in the embodiment of the present application.

In summary, in the projection lens provided by the embodiments of the present application, since the galvanometer is arranged in the projection lens, compared with related technologies, the distance from the light valve to the projection lens in the projection imaging device can be shortened, thereby reducing the projection imaging The volume of the device simplifies the structure of the projection imaging device, which is beneficial to the miniaturization of the projection imaging device.

In addition, since the galvanometer is placed between the TIR prism and the projection lens in the related art, the temperature of the galvanometer is relatively high, and the galvanometer is a heating element, which will cause the temperature of the rear group of the projection lens to be too high, thereby affecting Projection lens analysis. If the galvanometer is placed in the projection lens, heat dissipation is easier, and a heat source is reduced at the rear group of the projection lens, which reduces the temperature at the rear group of the projection lens, which is beneficial to the analysis of the projection lens. Compared with the galvanometer placed between the TIR prism and the projection lens in the related art, the galvanometer proposed in the embodiment of this application is placed in the projection lens, which avoids the temperature affecting the normal operation of the galvanometer and the projection lens, and reduces The design difficulty of the projection lens.

The embodiment of the application provides a projection imaging device, because the projection lens can be a telecentric design structure (that is, the optical path of the projection lens is a telecentric optical path) or a non-telescopic design structure (that is, the optical path of the projection lens is It is a non-telecentric optical path). Therefore, the projection imaging device can also be divided into a telecentric architecture and a non-telecentric architecture with lenses of different structures. FIG. 19 is a schematic structural diagram of a projection imaging device provided by an embodiment of the present application. When the projection imaging device is a non-telecentric architecture, as shown in FIG. 19, the projection imaging device 30 includes: a light valve 31 and any projection lens 20 provided in the foregoing embodiments. Wherein, the light valve 21 is used to generate an image beam when illuminated. For example, the light valve may be a DMD, and the projection lens is a 4K ultra-short throw projection lens.

It should be noted that in the projection imaging device of the embodiment of the present application, the resolution of the DMD is less than the resolution of the image to be projected. When the resolution of the image to be projected is 4K, the resolution of the DMD is less than 4K. The resolution is higher, such as 8K, the same DMD resolution is also less than 8K, which requires the use of galvanometer to achieve high-definition image display through image superposition. At this time, the resolution ability of the ultra-short throw projection lens is also corresponding Can achieve higher resolution display.

Optionally, FIG. 20 is a schematic structural diagram of another projection imaging device provided by an embodiment of the present application. When the projection imaging device has a telecentric architecture, as shown in FIG. 20, the projection imaging device 2 further includes a TIR prism 34, and the TIR prism 23 is located between the light valve 21 and the projection lens 20. The TIR prism 23 is used to reflect the image beam to the projection lens. For example, the TIR prism may be a total reflection prism. In the projection lens of the telecentric design structure, the image beam emitted from the same point on the light valve does not change with the change of the light valve position, which avoids the projection parallax caused by the inaccurate focus of the projection lens or the existence of the depth of field. The non-telecentric design structure of the projection lens has better image quality and higher uniformity of the projected image. Therefore, in practical applications, the projection lens mostly adopts the telecentric design structure, and the projection imaging device also adopts the telecentric structure.

In summary, in the projection imaging device provided by the embodiments of the present application, since the galvanometer is arranged in the projection lens, compared with the related art, the distance from the light valve to the projection lens in the projection imaging device can be shortened, thereby reducing the projection The volume of the imaging device simplifies the structure of the projection imaging device, which is beneficial to realize the miniaturization of the projection imaging device.

The above are only optional embodiments of this application and are not intended to limit this application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of this application shall be included in the protection of this application Within range.

Claims

A projection imaging device, characterized in that the projection imaging device includes a light valve and a projection lens, the projection lens includes a flat mirror group, a refractive mirror group, and a curved mirror group, and the flat mirror group includes at least one A reflecting mirror, the plane reflecting mirror group is arranged between a part of the refractive lens group and the curved reflecting mirror group;

The image light beam emitted by the light valve is transmitted through at least part of the lenses of the refracting mirror group, then enters the flat mirror group, and is reflected by the flat mirror group at least once, and then enters the curved mirror group; The curved mirror group is used to reflect and image the image beam on the screen.
The projection imaging device according to claim 1, wherein the plane mirror group includes a first mirror, the refraction mirror group includes a first refraction mirror group and a second refraction mirror group, and the first refraction mirror group The mirror group, the first reflecting mirror and the second refraction mirror group are arranged in order along the optical path direction of the projection lens.
The projection imaging device according to claim 1, wherein the flat mirror group comprises a second mirror, and the second mirror is located between the refracting mirror group and the curved mirror group.
The projection imaging device according to claim 1, wherein the plane mirror group includes a first mirror and a second mirror, and the refraction mirror group includes a first refraction mirror group and a second refraction mirror group;

The first mirror is located between the first refraction mirror group and the second refraction mirror group, and the second mirror is located between the second refraction mirror group and the curved mirror group.
4. The projection imaging device of claim 4, wherein the direction of the image light beam emitted to the first mirror is parallel to the direction of the image light beam emitted from the second mirror.
The projection imaging device according to claim 2 or 4, wherein the first reflecting mirror is a reflecting galvanometer.
The projection imaging device according to claim 3 or 4, wherein the second reflecting mirror is a reflecting galvanometer.
8. The projection imaging device according to claim 7, wherein the second reflecting mirror is located on the imaging surface of the refractive lens group.
The projection imaging device according to claim 1, wherein the projection imaging device further comprises a transmission type galvanometer, and the transmission type galvanometer is located in the refraction lens group.
9. The projection imaging device according to claim 9, wherein the transmissive galvanometer includes an optical lens and a driving component;

The driving component is used to drive the optical lens to swing at a specified angle according to a target frequency.
11. The projection imaging device according to claim 10, wherein the specified angle is negatively related to the incident angle of the image beam on the light incident surface of the optical lens.
The projection imaging device according to claim 11, wherein the incident angle is less than 16°.
The projection imaging device according to claim 1, wherein the projection lens further comprises a galvanometer, and the galvanometer is located on a side of the first refracting lens group away from the first reflecting mirror for receiving The light emitted by the light valve directs the light toward the first refracting lens group.