WO2020119421A1

WO2020119421A1 - Projection imaging system and laser projection device

Info

Publication number: WO2020119421A1
Application number: PCT/CN2019/120143
Authority: WO
Inventors: 阴亮; 罗超; 马铭晨
Original assignee: 青岛海信激光显示股份有限公司
Priority date: 2018-12-10
Filing date: 2019-11-22
Publication date: 2020-06-18
Also published as: CN111290101A

Abstract

A projection imaging system and a laser projection device. The projection imaging system comprises a light valve (10) and a projection lens (40). The light valve (10) is used to modulate a light beam so as to generate an image beam, and to output the image beam to the projection lens (40). The projection lens (40) comprises a first lens group (411), a relay lens (412), and a second lens group (413). The first lens set (411) comprises, in a transmission direction of an incident image beam, a first non-spherical lens (4114), a cemented-lens group consisting of a triple cemented lens (4111) and a double cemented lens (4112), and a second non-spherical lens (4118) located between the triple cemented lens (4111) and the double cemented lens (4112). The relay lens (412) comprises n lenses, where 1 ≤ n ≤ 2. The second lens group (413) comprises N lenses, where 2 < N < 5. The invention enables miniaturization of projection imaging systems and devices.

Description

Projection imaging system and laser projection equipment

This application requires the priority of the Chinese patent application submitted to the Chinese Patent Office on December 10, 2018, with the application number 201811506490.7 and the application name "projection imaging system and laser projection equipment", the entire contents of which are incorporated by reference in this application .

Technical field

The present application relates to the field of laser projection, in particular to a projection imaging system and laser projection equipment.

Background technique

Laser display projection technology is a new type of projection display technology currently on the market. For laser projectors applying this technology, especially for ultra-short throw projection equipment, on the one hand, the pursuit of short-focus projection at a short distance has become a trend. With the widespread use of commercial education at home, the miniaturization of projection equipment has become a new demand.

In the imaging system, the projection lens is one of the core components of the laser projector. The projection lens is very important from design to processing.

In order to achieve higher image quality (such as 4K image quality), current projection lenses need to have a higher resolution. Especially for ultra-short throw lenses, the projection ratio is small and the lens design complexity is higher. The number of lenses required is also very large. For example, the number of lenses for ultra-short throw lenses currently on the market is generally around 20 lenses. However, a larger number of lenses not only has higher processing and assembly complexity, but also makes the projection lens larger in size, which is not conducive to the miniaturization of projection equipment.

Summary of the invention

The embodiments of the present application provide a projection lens and a projection imaging system, which can solve the problem of a large projection lens volume. The technical solution is as follows:

In a first aspect, a projection imaging system is provided, including: a light valve for modulating a received illumination beam to generate an image beam, and outputting the image beam to a projection lens;

Projection lens, used to image the image beam, including:

Arrange the refraction system and reflection system in sequence along the direction of image beam incident transmission,

The refraction system is used to refract the image beam entering the refraction system into the reflection system;

The reflection system is used to reflect and image the image beam output by the refraction system onto the projection medium;

The refraction system includes a first lens group, a relay lens, a second lens group,

Along the direction in which the image beam is incident and transmitted, the first lens group includes a first aspheric lens, a cemented lens group composed of a triple cemented lens and a double cemented lens, and a second lens located between the triple cemented lens and the double cemented lens Aspherical lens;

Relay lenses include n lenses, 1≤n≤2;

The second lens group includes N lenses, 2<N<5.

In a second aspect, a laser projection device is provided, including: a laser light source and the above-mentioned projection imaging system.

The technical solutions provided by the embodiments of the present application may include the following beneficial effects:

In the projection imaging system provided by the embodiment of the present application, the first lens group of the refraction system of the projection lens includes a triplet lens and a doublet lens, and a combination of two aspherical lenses. Both the triplet lens and the doublet lens It has high chromatic aberration correction ability, and the triplet lens and doublet lens cooperate with aspherical lens, which can correct five kinds of monochromatic aberration better, so that the projection lens can have higher chromatic aberration at the same time. The ability to correct aberrations and aberrations can greatly reduce the number of conventional lenses and lens combinations used, so that the projection lens has a higher resolution and the number of overall lenses of the projection lens is correspondingly reduced. At the same time, the projection lens is divided into the first lens Group, relay lens, and second lens group, through the above first lens group to effectively correct chromatic aberration and aberration, can greatly reduce the correction burden of the relay lens and the second lens group on imaging, so that the relay lens and the first lens group The two-lens group can use a smaller number of lenses, and the total number of lenses can be controlled within 20. The lens composition of the above projection lens can effectively shorten the length of the projection lens, which is conducive to achieving a compact size projection lens, which is conducive to achieving a compact projection Imaging system.

The laser projection device provided by the present application includes a laser light source and the projection imaging system of the above embodiment, which is beneficial to realize miniaturization of the laser projection device.

BRIEF DESCRIPTION

In order to more clearly explain the embodiments of the present application, the following will briefly introduce the drawings used in the description of the embodiments. Obviously, the drawings in the following description are only some embodiments of the present application. Ordinary technicians can obtain other drawings based on these drawings without creative work.

FIG. 1-1 is a schematic diagram of the optical principle of a projection imaging system according to an embodiment of the present application.

[Corrected according to Rule 91 06.12.2019]
Figure 1-2 is a schematic diagram of a projection imaging system based on Figure 1-1.

FIG. 2 is a schematic diagram of another projection imaging system involved in an embodiment of the present application.

3 is a schematic structural diagram of a projection lens provided by an exemplary embodiment of the present application.

4 is a schematic structural diagram of a projection lens provided by an exemplary embodiment of the present application.

5 is a schematic structural diagram of a projection lens provided by an exemplary embodiment of the present application.

6 is a schematic structural diagram of a projection lens provided by an exemplary embodiment of the present application.

7 is a schematic diagram of an imaging contrast simulation interface of a projection lens according to an exemplary embodiment of the present application.

8 is a schematic diagram of spot light spot imaging of a projection lens provided by an exemplary embodiment of the present application.

9 is an optical characteristic curve diagram of a projection lens provided by an exemplary embodiment of the present application.

10 is an optical characteristic curve diagram of a projection lens provided by an exemplary embodiment of the present application.

11 is an optical characteristic curve diagram of a projection lens provided by an exemplary embodiment of the present application.

12 is an optical characteristic curve diagram of a projection lens provided by an exemplary embodiment of the present application.

13 is an optical characteristic curve diagram of a projection lens provided by an exemplary embodiment of the present application.

14 is an optical characteristic curve diagram of a projection lens provided by an exemplary embodiment of the present application.

15 is an optical characteristic curve diagram of a projection lens provided by an exemplary embodiment of the present application.

16 is an optical characteristic curve diagram of a projection lens provided by an exemplary embodiment of the present application.

17 is an optical characteristic curve diagram of a projection lens provided by an exemplary embodiment of the present application.

18 is an optical characteristic curve diagram of a projection lens provided by an exemplary embodiment of the present application.

19 is a schematic diagram of the principle of a system imaging optical path of a projection imaging system according to an exemplary embodiment of the present application.

FIG. 20 is a schematic diagram of the image beam direction in the projection imaging system according to an exemplary embodiment of the present application.

21 is a schematic structural diagram of a laser projection device according to an exemplary embodiment of the present application.

22 is a schematic diagram of the optical principle of a laser projection device according to an exemplary embodiment of the present application.

The drawings herein are incorporated into the specification and constitute a part of the specification, show embodiments consistent with the application, and are used together with the specification to explain the principles of the application.

detailed description

In order to make the purpose, technical solutions and advantages of the present application more clear, the present application will be described in further detail below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present application, but not all the embodiments. Based on the embodiments in this application, all other embodiments obtained by a person of ordinary skill in the art without creative work fall within the protection scope of this application.

Please refer to FIG. 1-1, which shows a schematic diagram of the optical principle of the projection imaging system provided in some embodiments of the present application. Specifically, the projection imaging system includes a light valve 10 and an illumination light path part before the light beam enters the light valve 10. The illumination light path part is usually composed of a plurality of lenses. The illumination light path part is used to receive the light beam and homogenize the light beam. Magnification, or also including optical path turning, to meet the angle requirements of the light valve 10 on the incident light beam and the size of the incident light spot.

In the example of FIG. 1-1, a schematic diagram of a DLP optical system is provided, and the light valve 10 is a reflective light modulation device. The surface close to the light valve 10 is also provided with a prism 20 for reflecting the illumination light beam into the surface of the light valve 10 and guiding the light beam reflected by the light valve 10 into the projection lens 40. The prism 20 may be a total internal reflection TIR prism (English: Total INterNal Reflection, abbreviated as: TIR), or a RTIR (Reverse Total INterNal Reflection, abbreviated as: RTIR) prism. In the example of FIG. 1-1, the prism 20 is a TIR prism.

Specifically, please refer to FIG. 1-2, which shows a schematic diagram of the projection imaging system architecture provided in FIG. 1-1. The projection imaging system may include: a light valve 10, a TIR prism 20, and a projection lens 40. The light valve 10 and the TIR prism 20 are sequentially arranged in a direction close to the projection lens 40. The light valve is used to generate an image beam when exposed to light. For example, in a DLP projection optical architecture, the light valve may be a digital micromirror device (English: Digital Micromirror Device, DMD for short), and the DMD chip is A reflective light modulation component that receives an illumination light beam and is driven by an image processing signal to invert at different angles, modulates the illumination light beam, and projects it into the lens. The resolution of the device can be 2K, 3K or 4K resolution, the 2K resolution refers to the pixel value of each line of the device reaching or close to 2000, usually refers to the 2560×1440 resolution; the 3K resolution refers to The pixel value of each line of the device is at or close to 3000, usually referring to the resolution of 3200×1800; the 4K resolution refers to the pixel value of each line of the device reaching or close to 4096, usually referring to the resolution of 4096×2160 The TIR prism is used to project the image beam to the projection lens to improve the brightness and contrast of the image beam entering the lens.

Optionally, please refer to FIG. 2, which illustrates a schematic diagram of another projection imaging system involved in the projection lens provided in some embodiments of the present application. The projection imaging system involved in the projection lens may further include: an image shift mirror group 30 located on the side of the TIR prism 20 close to the projection lens 40, the image shift mirror group used to reflect the TIR prism After the image beam is shifted, the shifted image beam is transferred to the projection lens. Specifically, the image shift mirror group vibrates so that the image beams corresponding to the two adjacent projected images passing through the image shift mirror group do not completely overlap, and the image beams corresponding to the two adjacent projected images are sequentially directed toward the projection lens . For example, the image shift mirror group may be a plate-shaped transparent device, such as a flat transparent glass. The functions and positions of other devices in FIG. 2 can be referred to those of FIG. 1. This embodiment of the present application will not repeat them here.

In the embodiment of the present application, a projection lens 40 is also provided, which can be applied to the implementation environment shown in FIG. 1-2 or FIG. 2. As shown in FIG. 3, the projection lens 40 includes:

Refraction system 41 and reflection system 42. The refraction system 41 and the reflection system 42 are sequentially arranged along the direction in which the image beam is incident and transmitted (ie, the X direction shown in FIG. 3) and share the optical axis L. The refraction system 41 is used to refract the image beam entering the refraction system into the reflection system. The refraction system is specifically used to perform aberration correction and chromatic aberration correction on the image beam entering the refraction system, and refract the image beam into the reflection system. The reflection system 42 is used to reflect the image beam output by the refraction system to the projection screen. The reflection system is specifically used to correct the distortion of the image beam output by the refraction system and reflect the image beam to the projection screen.

The refractive system 41 includes a triplet lens 4111 and a doublet lens 4112.

In summary, the first lens group of the refraction system of the projection lens and the projection lens in the projection imaging system provided by the embodiments of the present application includes a triplet lens and a doublet lens, and a combination of two aspheric lenses. Both the cemented lens and the double cemented lens have a high chromatic aberration correction capability, and the three cemented lens and the double cemented lens cooperate with the aspherical lens to better correct five kinds of monochromatic aberrations, so that the projection can be made The lens has a high chromatic aberration and aberration correction capability, which can greatly reduce the number of conventional lenses and lens combinations used, so that while the projection lens has a higher resolution, the number of overall lenses of the projection lens is correspondingly reduced. The projection lens is divided into a first lens group, a relay lens, and a second lens group. The above-mentioned first lens group effectively corrects chromatic aberration and aberration, which can greatly reduce the imaging correction burden of the relay lens and the second lens group Therefore, a smaller number of lenses can be used for the relay lens and the second lens group. The lens composition of the above-mentioned projection lens can effectively shorten the length of the projection lens, which is beneficial to realize the miniaturization of the projection lens and the projection imaging system.

Optionally, as shown in FIG. 4, the above-mentioned refraction system 41 includes a first lens group 411, a relay lens 412, and a second lens that are sequentially arranged along the direction in which the image beam is incident and transmitted (ie, the X direction shown in FIG. 4) Group 413, the first lens group 411 includes a triplet lens 4111 and a doublet lens 4112.

It should be noted that in the lens optical design, a unit composed of multiple lenses is usually regarded as a group, and it can be intuitively moved as a unit as a whole. For example, there are 10 lenses in the lens and 5 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 adjustment of tolerance during assembly, or it can be implemented in conjunction with the lens zoom to achieve the group The distance changes while changing the focal length of the lens. The relative position of the lens between each group does not change, and each group has its own focal length parameter.

In the embodiment of the present application, the first lens group 411, the relay lens 412, and the second lens group 413 may be referred to as a rear group, a middle group, and a front group. In this case, after having a higher aberration and chromatic aberration Under the premise of correction capability, the lens can have a large depth of field and a large tolerance range, that is, it can allow the movement of the focal plane and can also achieve the projection quality within the visual reception range. For example, at 100 inches, the projection quality The effect is the best, but at 90 inches or 120 inches, the position of the focal plane is changed by moving the group and the middle group (distortion correction must be performed at the same time through the movement of the two groups), although the 100 inch is not the best Resolution ability, but still meet the visual viewing requirements, that is, have a certain range of projection size adjustment, and at this time you need to have three groups of division, the rear group, the middle group move independently, that is, the first lens group 411 The relay lenses 412 each serve as a unit of adjustment, so that each is regarded as a group. But if the projection lens determines to achieve a 100-inch projection size, at this time, in order to meet the small design tolerance adjustment, assembly and other reasons, the above lenses can be divided into two groups, that is, the first lens group 411 is the rear group, The relay lens 412 and the second lens group 413 are the front group, so that only the first lens group 411 is slightly displaced with respect to the remaining lens group, and is mounted as a whole when assembled. At this time, the relay lens 412 maintains its relative position with respect to the second lens group 413.

In the following embodiments of the specification, in order to conveniently introduce the processing procedure of the projection lens on the beam in sequence, the projection lens is exemplarily divided into three groups. This can be used to divide the beams of different groups in the case of a finer group division. And the contribution of each group to beam imaging, but this does not limit the division of the projection lens of this embodiment. As described above, the relay lens may also be divided into the second lens group, so that the projection lens of this embodiment has two groups.

Optionally, the projection lens 40 may be an object-side telecentric design structure, that is, the optical path of the projection lens is an object-side telecentric optical path, and in the projection lens of the object-side telecentric design structure, the light valve emits at the same point The imaging beam does not change with the position of the light valve, which avoids the projection parallax caused by the inaccurate focus of the projection lens or the depth of field. The image quality is better than the projection lens of the non-object telecentric design structure.

Optionally, in the projection lens, the range of the ratio of the second focal length to the first focal length is 2-12, the first focal length is the equivalent focal length of the projection lens, and the second focal length is the equivalent focal length of the first lens group; The range of the ratio of the third focal length to the first focal length is 20-30, the third focal length is the equivalent focal length of the relay lens; the range of the ratio of the fourth focal length to the first focal length is 25-35, the fourth focal length is The equivalent focal length of the second lens group; the ratio of the fifth focal length to the first focal length is in the range of 5-10, and this fifth focal length is the equivalent focal length of the reflection system. The equivalent focal length is the focal length of the lens corresponding to the same imaging angle of view on the 135 camera converted from the angle of view of the imaging elements of different sizes.

Alternatively, the reflection system 42 may be a concave aspheric mirror.

Optionally, please refer to FIG. 4, the first lens group 411 (may be referred to as a rear group group) may include three cemented spherical lenses 4111 arranged in sequence along the direction of incidence and transmission of the image beam, and the third lens of positive power The two aspherical lens 4118 and the double cemented spherical surface 4112.

Alternatively, please refer to FIG. 5, the first lens group 411 may include a first aspheric lens 4114 with positive power, a triple cemented spherical lens 4111, and a second with positive power, which are sequentially arranged along the direction of incidence and transmission of the image beam An aspheric lens 4118 and a double cemented spherical lens 4112.

Optionally, as shown in FIG. 6, the first lens group 411 may further include other lenses. For example, the first lens group 411 may include m lenses, where m is a positive integer, and 6<m<16. For example, the first lens group 411 includes 11 lenses, and the 11 lenses include 2 aspherical mirrors and 9 spherical mirrors. The first lens group includes a first spherical lens 4113 of positive power, a first aspheric lens 4114 of positive power, a triple-glue spherical lens 4111, a negative power, and a negative power The second spherical lens 4115, the third spherical lens 4116 of positive power, the fourth spherical lens 4117 of negative power, the second aspheric lens 4118 of positive power, and the double-coated spherical lens 4112.

It should be noted that in the projection lens, F/# is a parameter that reflects the system's ability to collect or collect light, F/# = f/d, where f is the focal length, d is the aperture of the diaphragm, and / indicates division number. The smaller the value of F/#, the stronger the system's ability to receive or collect light.

As mentioned above, in order to ensure better image quality, the projection lens adopts the telecentric design structure of the object side, but the projection lens under the telecentric design structure of the object side is compared with the projection lens of the telecentric design structure of the non-object side The difference is larger, so a larger aberration needs to be eliminated. In order to eliminate this larger aberration and meet the design requirements of the lens lens F/# smaller value, a lens close to the light valve can be used to undertake the main aberration correction function of the projection lens.

Please continue to refer to FIG. 6, the first spherical lens 4113 is the first lens of the first lens group (also called the rear group). Since the first spherical lens 4113 is close to the light valve, the first spherical lens 4113 can play a role The projection lens has a large aberration correction effect. Therefore, it is necessary to select a material with a large refractive index. The larger the refractive index, the stronger the ability to correct aberration. For example, the range of the refractive index of the material may be greater than 1.62. .

Because the first spherical lens has a large aberration correction function, that is, its aberration correction ability is strong, therefore, within the range of the overall aberration tolerance of the projection lens system, the correction aberration ability can be selected according to the situation A slightly lower aspheric lens is used as the first aspheric lens 4117 to perform aberration correction. The higher the refractive index of the material, the greater the chromatic aberration it produces. In the case where the refractive index of the material of the first spherical lens is high, in order to control the chromatic aberration range of the projection lens, the first aspherical lens chooses a lower refractive index s material. For example, the first aspherical lens may be made of glass material with a model number of L-BSL7, D-K59 or L-BAL42. The value of the refractive index of the material may be about 1.5. The first aspheric mirror mainly corrects the astigmatism, coma and field curvature of the projection lens.

It should be noted that the first spherical lens and the first aspheric lens can be replaced by the first lens, that is, the first lens group includes the first optical power of the positive power arranged in sequence along the direction of the image beam incidence and transmission One lens, triplet spherical lens, second spherical lens with negative power, third spherical lens with positive power, fourth spherical lens with negative power, second aspheric lens with positive power, double cemented spherical surface Lens, thereby further reducing the volume of the projection lens and reducing costs. For example, the first lens may be a spherical lens.

Optionally, the triplet spherical lens 4111 includes: a fifth spherical lens c of positive power, a sixth spherical lens b of negative power, and a third of positive power, which are sequentially arranged along the direction of incidence and transmission of the image beam Seven spherical lens a. The three-glue spherical lens 4111 is mainly for correcting the chromatic aberration of the projection lens, and at the same time has a certain correction capability for the aberration of the projection lens. In order for the triple-glue spherical lens to correct the chromatic aberration of the projection lens, the three lenses in the triple-glue lens should be matched with materials whose Abbe number (also called dispersion coefficient) difference is greater than the first specified threshold. The specified threshold may be determined in combination with other configuration conditions of the projection lens. For example, the range of the first specified threshold may be 30-80. Therefore, after selecting the Abbe number of the sixth spherical lens b as small as possible, the Abbe numbers of the fifth spherical lens c and the seventh spherical lens a are larger within the first specified threshold range. For example, the sixth spherical lens b The value range of the Abbe number of b may be less than 35, for example, 31.3. The value range of the Abbe number of the fifth spherical lens c and the seventh spherical lens a may be 65-95, for example, the fifth spherical lens c The Abbe number can be 70 or 90.

The Abbe number above is used to indicate the dispersion capacity of a transparent medium. Generally speaking, the greater the refractive index of the medium, the greater the dispersion, and the smaller the Abbe number; conversely, the smaller the refractive index of the medium, the less obvious the dispersion, and the larger the Abbe number.

However, since the smaller the Abbe number of the material, the larger the refractive index, and the larger the refractive index, the higher the absorption rate of the blue wavelength band. In order to reduce the absorption rate of the sixth spherical lens to the blue wavelength band, the The six spherical lens selects a negative power lens to make the image beam pass through the thinner area of the sixth spherical lens, thereby improving the geometric optical transmission efficiency of the sixth spherical lens, that is, the sixth spherical lens transmits the image beam effectiveness. Exemplarily, the value range of the refractive index of the sixth spherical lens may be greater than 1.8, and the value range of the refractive index of the fifth spherical lens may be 1.45-1.55.

The second spherical lens 4115 is a meniscus spherical lens, the third spherical lens 4116 is a biconvex spherical lens, the fourth spherical lens 4117 is a double concave spherical lens, and the second aspheric lens 4118 is a positive-focus aspheric lens. The second aspheric mirror 4118 is mainly used to correct the spherical aberration and curvature of field of the projection lens.

Optionally, the double-glued spherical lens 4112 includes: an eighth spherical lens e of negative power and a ninth spherical lens d of positive power, which are sequentially arranged along the direction of incidence and transmission of the image beam. The double-glued spherical lens 4112 is mainly used for correcting the chromatic aberration of the projection lens, and at the same time has a certain correction capability for the aberration of the projection lens. Among them, since the image beam passes through the triple-glue spherical lens 4111, the residual chromatic aberration of the image beam of the projection lens of the image beam is relatively small, and the double-glue spherical lens 4112 has less chromatic aberration correction ability than the triple-glue spherical lens 4111. Therefore, the double cemented spherical lens 4112 can be used to accurately correct the remaining small chromatic aberration. The eighth spherical lens e and the ninth spherical lens d in the double cemented spherical lens 4112 are selected from materials whose Abbe number difference is less than the second specified threshold. Collocation, the second specified threshold can be determined in combination with other configuration conditions of the projection lens. For example, the ratio of the Abbe number of the eighth spherical lens e to the ninth spherical lens d may be 0.5-2, for example 1.65; the Abbe number of the eighth spherical lens e and the ninth spherical lens d The values of can be 40.76 and 25.68, in this case, the ratio of the Abbe number of the eighth spherical lens e to the ninth spherical lens d is about 1.59. At the same time, the power of the eighth spherical lens e may be negative, and the power of the ninth spherical lens d may be positive, and then the positive chromatic aberration generated by the image beam passing through the eighth spherical lens e and passing through the ninth The negative chromatic aberration generated by the spherical lens d cooperates with each other, so that the eighth spherical lens e and the ninth spherical lens d can correct the chromatic aberration of the image beam to zero.

It should be noted that the order of the positions of the triplet lens and the doublet lens in the lens group can be changed.

Optionally, the relay lens 412 may be a single lens or a combination of two lenses. Preferably, in this embodiment, it is a single lens and a spherical lens. For example, the lens may be a positive power spherical lens . The relay lens 412 has a positive lens characteristic, that is, has the ability to condense light, and is used to reduce the normalized height of the image beam output by the first lens group 411 on each lens in the second lens group 412. The normalized height refers to the ratio of the effective aperture of the lens (that is, the maximum height corresponding to the beam range of the image beam) and the lens aperture (that is, the maximum diameter of the lens, that is, the height of the lens) when the image beam passes through a lens (The maximum height is parallel to the direction of the lens height), which is to reduce the longitudinal height of the image beam. By reducing the propagation height of the image beam, the size of each lens aperture in the second lens group 413 and the first lens group 411 can be reduced, which is beneficial to reducing the volume of the projection lens and reducing costs. For example, the surface shape of the one relay lens may be a plano-convex type or a biconvex type.

Optionally, the second lens group (may be referred to as a front group) 413 includes N lenses, where N is a positive integer and 2<N<5. For example, the second lens group 413 includes 3 lenses, and the 3 lenses include 1 aspherical mirror and 2 spherical mirrors. The second lens group 413 includes: a tenth spherical lens with positive power 4131, an eleventh spherical lens with negative power 4132, and a third aspheric surface with negative power, which are sequentially arranged along the direction in which the image beam is incident and transmitted Lens 4133. The second lens group 413 is used to correct the distortion of the projection lens. Among them, the third aspheric lens 4133 is mainly used to correct astigmatism, curvature of field and distortion. Exemplarily, the tenth spherical lens 4131 may have a biconvex shape with a refractive index of about 1.7, for example, 1.72, and a dispersion coefficient of 54.6. The surface shape of the eleventh spherical lens 4132 may be a double-concave type, with a middle thickness of 3-3.5 mm, so that when the image beam passes through the eleventh spherical lens, the middle thickness can effectively reduce the image For the light loss of the light beam, the value range of the dispersion coefficient of the eleventh spherical lens may be greater than 50. The refractive index of the third aspheric surface 4133 is about 1.5.

Optionally, due to the regular shape of the symmetric aspheric lens, it is easy to process and manufacture, especially the rotationally symmetric aspheric lens, which is easier to process and manufacture. Therefore, when the aspheric lens in the projection lens, such as the first aspheric lens, the first When both the second aspherical lens and the third aspherical lens adopt a rotationally symmetric structure, the processing method of the aspherical lens can be simplified, which further simplifies the processing of the projection lens and reduces the production cost.

It should be noted that the lens of the projection lens is usually made of glass material, but the price of the glass material is relatively high, and for the aspheric lens, the processing of the aspheric lens of the glass material is more difficult, and the third aspheric lens and the light valve The distance is longer, the diameter is larger, and it is more consumable. Therefore, the material of the third aspheric lens can be plastic, such as 480R, the price of the plastic material is lower, and for aspheric lens, the processing of the aspheric lens of plastic material Easier.

Optionally, the projection lens further includes: an aperture stop, which is located in the first lens group. For example, both sides of the aperture stop are spherical lenses, specifically, located in the second lens group Between the spherical lens and the third spherical lens, an aperture stop is used to limit the entrance pupil diameter. Since the two sides of the aperture stop are spherical lenses, compared with the case where aspheric lenses are distributed on both sides, the design difficulty of the lens can be reduced and the cost can be reduced.

It should be noted that since the aperture stop is used to limit the entrance pupil diameter, the energy density distribution around it is high, and the temperature near the aperture stop is high. Therefore, in order to reduce the influence of the temperature near the aperture stop on the lens, the lens near the aperture stop needs to select a material with a small expansion coefficient. For example, the lens can be made of glass materials with model numbers L-TIM28, L-AM69HE and L-LALB. The material with a smaller expansion coefficient can reduce the lens profile caused by the temperature change of the lens material ( That is, the R value, that is, the change of the radius of curvature of the lens, so as to reduce the influence of temperature drift on the projection lens.

Further, the range of the effective focal length of the projection lens provided in the embodiment of the present application may be 1.964-3.273 mm (millimeters). For example, the effective focal length of the projection lens provided in this embodiment is 2.348 mm, which is an ultra-short throw projection lens. The effective focal length is the distance from the main image plane to the paraxial image plane after the projection lens. In the embodiment of the present application, when the projection screen of the projection lens is 100 inches, the projection ratio of the projection lens ≤ 0.24, the projection ratio refers to the linear relationship between the linear distance between the mirror and the screen and the length of the projection screen, that is, the projection distance/screen length The size and projection ratio reflect the ultra-short throw characteristics of the lens. In another optional embodiment, the size of the projection screen of the projection lens may be 90-120 inches, and the projection ratio is 0.23-0.25. Compared with the traditional non-ultra-short throw projector, the ultra-short throw projection lens has a smaller projection (less than 1). Therefore, the projection lens can be placed close to the projection screen, saving a lot of space. It avoids the blocking of the image beam when it needs to be close to the projection screen.

In an embodiment of the present application, when the size of the projection screen of the projection lens is adjustable, preferably, the distance between the second lens group and the reflector is relatively fixed, and by moving the first lens group, the relay lens is relatively second The distance of the lens group can realize the adjustment of the projection size. In order to improve the adjustment efficiency, the distance between the second lens group and the reflection mirror may be finely adjusted, and the adjustment distance range is within plus or minus 1 mm.

When the projection screen size of the projection lens is fixed, the distance between the second lens group and the reflector is relatively fixed, for example, 69.66971912 mm or 71 mm.

In the embodiment of the projection lens of the present application, a triple cemented lens, a double cemented lens, and three aspherical lenses are used in conjunction with other lenses to have strong aberration and chromatic aberration correction capabilities. The embodiments of the present application provide The resolution of a projection lens can usually be 93lp/mm (that is, the resolution required by 4K resolution), then the projection lens can parse an image of 4K resolution, so that the projection screen can present a higher-definition image, improving the user experience.

In the projection lens provided by the embodiment of the present application, the total length of the refraction system is L1 (ie, the distance from the edge surface of the first spherical lens close to the light valve to the edge surface of the third aspheric lens close to the reflection system), The distance between the refraction system and the reflection system is L2, where 1.4<L1/L2<1.6. Since the thickness of the lens in the reflection system is negligible, the L2 can be the total length of the projection lens minus L1.

Due to the reduction in the number of lenses used, in the projection lenses provided in the embodiments of the present application, the number of lenses used is less than 16, so that the length of the projection lens is in the range of 197-203mm, and the length of the conventional projection lens is at least 210mm. The number is also about 20 pieces. The maximum value of the length of the projection lens is smaller than the minimum value of the length of the conventional projection lens, the length is smaller than the length of the conventional projection lens, and the maximum aperture of the lens in the projection lens is 52mm. The maximum aperture of the lens in a conventional projection lens is 60 mm, and the maximum aperture is also smaller than the maximum aperture of a conventional projection lens. Therefore, the overall volume of the projection lens is small.

In an embodiment of the present application, when the projection lens includes: a first spherical lens, a first aspheric lens, a fifth spherical lens, a sixth spherical lens, a first Seven spherical lens, second spherical lens, third spherical lens, fourth spherical lens, second aspheric lens, eighth spherical lens, ninth spherical lens, relay lens, tenth spherical lens, eleventh spherical lens, When the third aspheric lens and the reflection system are used, the thickness of each lens (except the reflection system) of the projection lens along the direction of the image beam incident transmission is: 7.79925152mm, 7.02mm, 5.03mm, 1.5mm, 4.32mm , 3.5mm, 4.27622172mm, 1.8mm, 4.47553268mm, 1.5mm, 4.58mm, 6.11544835mm, 14.7mm, 3.5mm and 3.45mm. The successive distances between the lenses of the projection lens along the direction of the image beam incidence transmission are: 0.249mm, 0.249mm, 0mm, 0mm, 0.93mm, 0.5mm, 0.3mm, 1.133mm, 0.6946996mm, 0mm, 7.42962132mm, 11.88678689mm, 2.63083486mm, 3.76248103mm and 69.66971912mm.

Please refer to FIG. 7, which is a schematic diagram of an imaging contrast simulation interface of a projection lens according to an embodiment of the present application, and is also a distortion analysis diagram of a projection imaging system. As shown in FIG. 7, the cross line (+) in FIG. 7 is pre-imaging For the position, the cross (x) is the imaging position of the actual projection lens. The higher the overlap rate of the cross line and the cross, the lower the distortion value of the image and the lower the distortion of the image. Assuming that the projection lens is 100 inches (2214×1245mm2) in the projection screen, the wavelength of the image beam is 0.5500μm, and the zoom ratio is 1, as can be seen from FIG. 7, the pre-imaging position and the actual projection lens have a higher coincidence rate. The maximum distortion value simulated in the simulation interface is 0.3841%. Therefore, the distortion of the imaging of the projection lens is low.

Please refer to FIG. 8. FIG. 8 is a schematic diagram of a point array simulation interface of a projection lens provided by an embodiment of the present application, which is also called a schematic diagram of spot light imaging. In Fig. 8, light rays with wavelengths of 0.4550um, 0.5500um and 0.6200um are drawn respectively. Under 10 different field of view conditions, the spot light spots on the projection screen are imaged after passing through the projection lens, and the 10 fields of view are respectively labeled 1-10 logo. Among them, "+" indicates spot imaging of light with a wavelength of 0.4550um, "×" indicates spot imaging of light with a wavelength of 0.5500um, and "□" indicates spot imaging of light with a wavelength of 0.6200um. The closer the size of the spot spot image (also called the diameter of the entire diffuse spot, that is, the geometric radius, marked by GEO in Figure 8) to the diffraction limit of 1.392um, the higher the image quality contrast of the projection lens. The scale bar in FIG. 8 (the SCALE BAR logo is used in FIG. 8) is 40, that is, the size ratio of the image shown in FIG. 8 to the real image is 1:40, and the dotted line A in FIG. 8 records the label (FIB is used in FIG. 8 -O logo) in the field of view of 1-10 respectively, the simulated root mean square radius values (using the RMS and RADIUS logo in Figure 8) are 1.744, 1.497, 1.546, 1.906, 2.222, 2.356, 2.492, 3.245, 3.848 and 3.532, the geometric radii are 3.430, 3.765, 2.755, 4.492, 5.680, 5.986, 5.880, 9.316, 11.737 and 10.903, then the image size of the spot light spot on the projection screen is ≤11.737um, which is close to the diffraction limit of 1.392um, therefore, the The image quality of the projection lens has a high contrast.

Please refer to FIGS. 9 to 18, which are normalized optical characteristic curves of the 10 different fields of view labeled 1-10 shown in FIG. 9 of the projection lens provided in the embodiment of the present application shown in FIG. 9 The optical characteristic curve is also called the ray fan diagram (English: ray faN). The optical characteristic curve in each of FIGS. 9 to 18 is used to indicate that three wavelengths of light are relative to The difference between the dominant wavelength light (that is, the light passing through the light emitting point and the center point of the diaphragm) on the image plane. The wavelengths of the three types of light are 0.4550um, 0.5500um and 0.6200um, respectively. As shown in Figures 9 to 18, each optical characteristic curve includes the image synthesis error map M on the sagittal fan surface and the image synthesis error on the meridional fan surface. Figure N. In the coordinate system of the comprehensive error map M of the image on the sagittal fan surface, the horizontal axis PX is used to represent the normalized height of the light intake pupil on the sagittal fan, which passes through the pupil X The beam profile of the axis, EX is used to indicate the difference between the height of the image plane and the height of the chief ray of the current field of view on the image plane when the light passing through the specified pupil in the sagittal fan is incident on the image plane ; In the coordinate system of the integrated error map N of the image on the meridian fan, the horizontal axis PY is used to represent the normalized height of the light intake pupil on the meridian fan, which is the beam passing through the Y axis of the pupil The cross-section and the vertical axis EY are used to represent the difference between the height of the image plane and the height of the chief ray of the field of view on the image plane when the light passing through the designated pupil in the meridional light fan is incident on the image plane. In each graph, the higher the coincidence rate of multiple curves in the coordinate axis plane where EY and PY are located and the coordinate axis plane where EX and PX are, the smaller the chromatic aberration of the projection lens, when the curve is closer to the PY axis Or PX axis, the smaller the aberration of the projection lens. As can be seen from Figures 9 to 18, in the image comprehensive error graph on the sagittal fan surface and the image comprehensive error graph on the meridional fan surface under each field of view, the coincidence rates of multiple curves are higher and tend to be more Near the PY axis or PX axis, therefore, the chromatic aberration and aberration of the projection lens are small.

Further, for aspheric lenses, plastic materials are easier to process and have lower prices. Therefore, the material of the third aspheric lens can be plastic, which is beneficial to reduce the cost of the projection lens and reduce the difficulty of processing the projection lens.

As shown in FIG. 1, an embodiment of the present application provides a projection imaging system. The projection imaging system includes a light valve 10, a total internal reflection TIR prism 20, and a projection lens 40. The projection lens 40 is any projection lens provided by the embodiments of the present application. The light valve 10 and the TIR prism 20 are sequentially arranged in a direction close to the first lens group, and share an optical axis. The light valve is used to generate an image beam when exposed to light. For example, the light valve may be a digital micromirror device (English: Digital Micromirror Device, DMD for short), and the resolution of the DMD may be 2K, 3K Or 4K resolution. Exemplarily, the TIR prism may be 2 total reflection prisms, or 2N total reflection prisms, and N is an integer greater than 1.

Optionally, as shown in FIG. 2, the projection imaging system further includes an image shift mirror group 30 that is located on the side of the TIR prism 20 near the projection lens 40. The image shift mirror group is used to shift the image beam reflected by the TIR prism, and then transfer the shifted image beam to the projection lens. Specifically, the image shift mirror group 30 vibrates to sequentially pass the image shift The image beams corresponding to the two adjacent projection images of the mirror group 30 do not completely overlap, and the image beams corresponding to the two adjacent projection images are sequentially directed to the projection lens 40. For example, the image shift mirror group may be a plate-shaped transparent device, such as a flat transparent glass. When the image shift mirror group works, the image shift mirror group may be driven by a motor or other equipment to perform high-frequency vibration, thereby achieving the The offset of the image beam, through the misalignment of the beams of the two consecutive projection screens, causes the projection screen to be misaligned and superimposed. The temporary effect is used visually to obtain the clarity of the projection screen perceived by the human eye, thereby improving the projection display Resolution.

In the projection imaging system provided by the embodiment of the present application, the distance from the light valve to the first spherical lens of the first lens group is the back working distance of the lens, due to the back working distance and back focal length (English: Back Focal LeNgth, abbreviation: BFL ) Are approximately equal, therefore, the back working distance is also commonly referred to as BFL, the distance L2 between the refraction system and the reflection system in the projection lens, where 0.3<BFL/L2<0.55.

In the projection imaging system provided by the embodiment of the present application, the total length of the refraction system is L1 (ie, the distance from the edge surface of the first spherical lens close to the light valve to the edge surface of the third aspheric lens close to the reflection system ), the distance between the refraction system and the reflection system is L2, where BFL satisfies: 0.05<BFL/(L1+L2)<0.25 to meet the ultra-short throw characteristics of the lens, that is, the characteristics of the ultra-short throw lens.

In the projection imaging system provided by the embodiment of the present application, the offset of the light valve pixel plane relative to the optical axis satisfies the relationship: 132%<offset<150%, the light valve pixel plane refers to the light valve reflecting the image beam flat.

And, in the projection imaging system provided by the embodiment of the present application, in order to cooperate with the miniaturization of the projection lens, the light valve DMD also adopts a small size model accordingly, so that the optical aperture exiting from the light valve is reduced, and the optical aperture of the projection lens lens It can also be smaller, which is conducive to the miniaturization of the projection lens volume. Specifically, the light valve uses a DMD of 0.47 inches.

Please refer to FIG. 19, which is a schematic diagram of the principle of the system imaging optical path of the projection imaging system according to the embodiment of the present application. As shown in FIG. 19, when the light valve is illuminated, the light valve outputs an image beam. The image beam is reflected by the TIR prism to the image shift mirror group, and then passed to the refraction system 41. The image beam passes through the After the refraction system 41, it is aggregated to a certain extent for the first imaging. After the imaged image beam enters the reflection system, the reflection system 42 reflects the image beam out and performs the second imaging on the projection screen. The screen displays the large-sized image obtained by the second imaging.

Please refer to FIG. 20, which is a schematic diagram of an image beam direction in a projection imaging system according to an embodiment of the present application. As shown in FIG. 20, after passing through the projection lens 40, the image beam is reflected onto the projection screen 50, and a large-sized image is displayed on the projection screen 50.

In summary, the first lens group of the refraction system of the projection lens and the projection lens in the projection imaging system provided by the embodiments of the present application includes a triplet lens and a doublet lens, and a combination of two aspheric lenses. Both the cemented lens and the double cemented lens have a high chromatic aberration correction capability, and the three cemented lens and the double cemented lens cooperate with the aspherical lens to better correct five kinds of monochromatic aberrations, so that the projection can be made The lens has a high chromatic aberration and aberration correction capability, which can greatly reduce the number of conventional lenses and lens combinations used, so that while the projection lens has a higher resolution, the number of overall lenses of the projection lens is correspondingly reduced. The projection lens is divided into a first lens group, a relay lens, and a second lens group. The above-mentioned first lens group effectively corrects chromatic aberration and aberration, which can greatly reduce the imaging correction burden of the relay lens and the second lens group Therefore, the relay lens and the second lens group can use a smaller number of lenses, and the total number of lenses can be controlled within 20. The lens composition of the above-mentioned projection lens can effectively shorten the length of the projection lens, which is conducive to achieving a miniaturized projection lens , Conducive to miniaturization of the projection imaging system.

At the same time, the light valve component uses a small-sized DMD chip, which is conducive to reducing the optical aperture entering the projection lens, can reduce the size of the lens, and is also conducive to the miniaturization of the projection lens volume.

And, the embodiments of the present application also provide a laser projection device. Specifically, as shown in FIG. 21, it is a schematic structural diagram of a laser projection device. The laser projection device may be a laser theater or a laser TV, or other laser projections. instrument. Fig. 22 shows a schematic diagram of the optical principle of a laser projection device.

As shown in FIG. 21, it includes a laser light source unit 01, an optomechanical unit 02, and a lens unit 03. Among them, the laser light source section 01, the optical machine section 02, and the lens section 03 can all be combined into an optical engine according to optical functions. The laser light source section 01 is used to provide an illumination beam, and the core component in the optomechanical section 02, a light valve, is used to modulate the image signal of the illumination beam to form an image beam, and project the image beam into the lens section 03. The lens section 03 includes a housing and a projection lens. The projection lens includes a plurality of lens groups for correcting, magnifying and imaging the modulated image light beam, and projecting onto a projection medium to form a projection screen. In the structure shown in FIG. 21, the various optical functional parts are connected in sequence along the beam propagation direction, and are wrapped by a housing that supports the optical components and enables each optical part to meet certain sealing or airtight requirements.

In a specific implementation, the laser light source section 01 may include a laser assembly and a fluorescence conversion system. The laser assembly includes at least a blue laser assembly and emits blue laser light. The fluorescence conversion system may be specifically a fluorescent wheel. Among them, the blue laser component is used as the excitation light source to excite the fluorescent wheel to emit primary color light other than blue, and the blue laser light emitted by the blue laser as the blue primary color light and the fluorescent color generated by the fluorescent wheel are used together for image display Three-color illumination beam. Alternatively, the laser light source section 01 may also be a pure three-color laser light source, including a blue laser component, a red laser component, and a green laser component, which emit blue laser light, red laser light, and green laser light respectively, and the three color lasers combine light to form an illumination beam .

The three-color illumination beam enters the optomechanical unit 02. The optomechanical unit 02 includes the core light modulation component-the light valve. The light valve reverses the positive and negative angles of the surface micro-mirror according to the drive signal corresponding to the image signal to complete Modulation of the illumination beam.

The modulated illumination light beam is projected into the optical part of the projection lens in the lens section 03 by the light valve, and is corrected, enlarged and imaged by a plurality of lens groups of the projection lens.

Among them, the optical portion in the optomechanical portion 02 and the optical portion in the lens portion 03 constitute the projection imaging system in the foregoing embodiment. Referring to the schematic diagram of the optical architecture of the laser projection device shown in FIG. 22, the light source 01 provides an illumination beam to the illumination optical path portion in the optical machine, and outputs it to the light valve 10, where the light valve 10 modulates the illumination beam and projects it into the projection lens 40 for imaging .

In the optical principle architecture shown in FIG. 22, a laser light source, a light valve, and a projection lens are the core components of laser projection imaging. For the projection imaging system composed of the light valve and the projection lens, please refer to the foregoing embodiments. The composition and working principle of the projection lens can also refer to the foregoing embodiments of the projection lens.

The above laser projection equipment is used for a projection imaging system that uses a miniaturized type. The laser light source can also be used. A miniaturized laser array, such as an MCL laser array, can output high brightness while the volume of the light source is still small. Laser projection equipment can also be miniaturized.

After considering the description and practicing the invention disclosed herein, those skilled in the art will easily think of other embodiments of the present application. This application is intended to cover any variations, uses, or adaptations of this application, which follow the general principles of this application and include common general knowledge or customary technical means in the technical field not disclosed in this application . The description and examples are only to be regarded as exemplary, and the true scope and spirit of this application are pointed out by the claims.

It should be understood that the present application is not limited to the precise structure that has been described above and shown in the drawings, and various modifications and changes can be made without departing from the scope thereof. The scope of this application is limited only by the appended claims.

Claims

A projection imaging system, characterized in that it includes:

The light valve is used to modulate the received illumination beam to generate an image beam, and output the image beam to the projection lens;

A projection lens is used to image the image beam. The projection lens includes:

Arrange the refraction system and the reflection system in sequence along the direction of the incident transmission of the image beam,

The refraction system is used to refract the image beam entering the refraction system into the reflection system;

The reflection system is used for reflecting and imaging the image beam output by the refraction system onto the projection medium;

The refraction system includes a first lens group, a relay lens, and a second lens group,

Along the direction in which the image beam is incident and transmitted, the first lens group includes a first aspheric lens, a cemented lens group composed of a triple cemented lens and a double cemented lens, and located on the triple cemented lens and double cemented The second aspherical lens between the lenses;

The relay lens includes n lenses, 1≤n≤2;

The second lens group includes N lenses, 2<N<5.
The projection imaging system according to claim 1, wherein:

The relay lens is used to reduce the normalized height of the image beam output by the first lens group on each lens in the second lens group.
The projection imaging system according to claim 1, wherein the relay lens is a spherical lens.
The projection imaging system according to claim 1, wherein:

The first lens group further includes a plurality of spherical lenses, the refractive system further includes an aperture stop, the aperture stop is located in the first lens group, and both sides of the aperture stop are spherical lenses .
The projection imaging system according to claim 4, wherein:

The first lens group includes m lenses, 6<m<16.
The projection imaging system according to claim 1, wherein:

The second lens group includes: a tenth spherical lens with positive power, an eleventh spherical lens with negative power, and a third non-spherical lens that are sequentially arranged along the direction of incidence and transmission of the image beam Spherical lens.
The projection imaging system according to claim 1, wherein:

The triple-glue spherical lens includes: a fifth spherical lens of positive power, a sixth spherical lens of negative power, and a seventh spherical lens of positive power, which are sequentially arranged along the direction of incidence and transmission of the image beam; The double-glued spherical lens includes: an eighth spherical lens of negative power and a ninth spherical lens of positive power, which are sequentially arranged along the direction of incidence and transmission of the image beam.
The projection imaging system according to claim 1, wherein the light valve is a 0.47 inch DMD chip.
The projection imaging system according to claim 4, wherein:

Along the direction in which the image beam is incident and transmitted, the first lens of the first lens group is a spherical lens.
The projection imaging system according to any one of claims 1 to 9, wherein

An image shift mirror group is further provided between the light valve and the projection lens, and the image shift mirror group vibrates so that the image beams corresponding to the two adjacent projected images of the image shift mirror group sequentially pass by Incomplete overlap, and the image beams corresponding to the two adjacent projected images are sequentially directed to the projection lens.
The projection imaging system according to any one of claims 1 to 9, wherein the projection lens is a telecentric object,

And, the projection imaging system further includes a TIR prism,

The TIR prism is used to project the image beam modulated by the light valve to the projection lens.
A laser projection device, characterized by comprising a laser light source, and the projection imaging system according to any one of claims 1 to 11;

The laser light source provides an illumination beam for the projection imaging system.