WO2020187204A1 - 激光投影设备 - Google Patents

激光投影设备 Download PDF

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Publication number
WO2020187204A1
WO2020187204A1 PCT/CN2020/079702 CN2020079702W WO2020187204A1 WO 2020187204 A1 WO2020187204 A1 WO 2020187204A1 CN 2020079702 W CN2020079702 W CN 2020079702W WO 2020187204 A1 WO2020187204 A1 WO 2020187204A1
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Prior art keywords
lens
group
projection
lens group
projection device
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PCT/CN2020/079702
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English (en)
French (fr)
Inventor
阴亮
李晓平
Original Assignee
青岛海信激光显示股份有限公司
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Priority claimed from CN201910691196.6A external-priority patent/CN112305700B/zh
Application filed by 青岛海信激光显示股份有限公司 filed Critical 青岛海信激光显示股份有限公司
Publication of WO2020187204A1 publication Critical patent/WO2020187204A1/zh

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    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B7/00—Mountings, adjusting means, or light-tight connections, for optical elements
    • G02B7/02—Mountings, adjusting means, or light-tight connections, for optical elements for lenses
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B7/00—Mountings, adjusting means, or light-tight connections, for optical elements
    • G02B7/18—Mountings, adjusting means, or light-tight connections, for optical elements for prisms; for mirrors
    • G02B7/182—Mountings, adjusting means, or light-tight connections, for optical elements for prisms; for mirrors for mirrors
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03B—APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR
    • G03B21/00—Projectors or projection-type viewers; Accessories therefor
    • G03B21/14—Details
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03B—APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR
    • G03B21/00—Projectors or projection-type viewers; Accessories therefor
    • G03B21/14—Details
    • G03B21/28—Reflectors in projection beam

Definitions

  • This application relates to the field of optical equipment, in particular to a laser projection equipment.
  • the projection lens needs to be designed in conjunction with the lighting system.
  • the lighting system is divided into a telecentric lighting system and a non-telecentric lighting system.
  • the projection lens is also correspondingly designed as a telecentric projection lens and a non-telecentric projection lens.
  • Ability is also different.
  • the improvement of the resolution capability of the projection lens increases the number of lenses used, and the design of the lens surface is more difficult.
  • the combination of lenses in a projection lens is usually more complicated.
  • the overall structure of the projection lens is more complicated, which is not conducive to the reduction of the lens volume.
  • the volume of the projection lens accounts for more than one-third of the optical engine of the projection equipment. This will also make the volume of the entire laser projection equipment difficult to shrink, making The equipment is cumbersome.
  • the embodiment of the present application provides a laser projection device, which facilitates the simplification of the optical structure and the compression of the device volume.
  • the technical solutions adopted are as follows:
  • a laser projection device including a light source, a light valve and a projection lens,
  • the light source is used to provide a laser beam to the light valve;
  • the light valve is used to modulate the laser beam provided by the light source and then emitted to the projection lens;
  • the projection lens is used to image the laser beam provided by the light valve to the projection screen;
  • the offset of the light valve pixel surface relative to the optical axis of the projection lens is 135% to 150%
  • the projection lens includes a refracting lens group and a reflecting mirror group.
  • the refracting lens group is provided with a first aspheric lens near the light valve, and a second aspheric lens is provided near the reflecting mirror group; the lenses in the remaining refracting lens group are all spherical lens;
  • the refractive lens group is further provided with a triple cemented lens, at least one single lens, a double cemented lens, and three single lenses in sequence;
  • the refractive lens group and the reflecting mirror group satisfy: 0.2 ⁇ L2/L1 ⁇ 0.5, where L1 is the length of the refractive lens group, and L2 is the distance between the refractive mirror group and the reflecting mirror group.
  • the projection lens includes a refraction lens group and a reflection mirror group.
  • an aspheric lens is provided at the front and rear of the lens group respectively, and a triplet lens is also provided between the aspheric lenses.
  • an aspheric lens is arranged at the rear of the refracting lens group close to the mirror group, which is farther from the diaphragm and has a larger field of view. It can better cooperate with the mirror group to correct the distortion of the system imaging, which is also conducive to Reduce the number of lenses.
  • the projection lens in the above-mentioned laser projection equipment compared with the related technology, under the same premise of realizing high-resolution ultra-short throw projection, the number of lenses is small, and the lens composition is efficient, so that the projection lens part can be obtained from the volume. Compression, the design of the lens group is simple, and the complexity is reduced. The number of aspheric lenses used in the above-mentioned projection lens is small, which is also conducive to the reduction of the cost of the projection lens and the improvement of the yield.
  • the laser projection device itself also has the above-mentioned beneficial effects.
  • Figure 1-1 is a schematic diagram of a projection imaging process of a projection lens provided by an embodiment of the present application
  • Figure 1-2 is a schematic diagram of the optical engine structure of a laser projection device provided by an embodiment of the present application.
  • Fig. 2 is a schematic diagram of a laser projection device provided by an embodiment of the present application.
  • Figure 3-1 is an optical schematic diagram of a laser projection device provided by an embodiment of the present application.
  • Figure 3-2 is another optical schematic diagram of a laser projection device provided by an embodiment of the present application.
  • Figure 3-3 is another optical schematic diagram of a laser projection device provided by an embodiment of the present application.
  • FIG. 4 is a schematic diagram of aberrations of the projection lens provided by the embodiment of the present application.
  • FIG. 5 is a schematic diagram of aberrations of the projection lens provided by the embodiment of the present application.
  • FIG. 6 is a schematic diagram of aberrations of the projection lens provided by the embodiment of the present application.
  • FIG. 7 is a schematic diagram of an optical path of a projection lens in the laser projection device shown in FIG. 2;
  • FIG. 8 is a schematic structural diagram of a projection lens in the laser projection equipment shown in FIG. 2.
  • FIG. 1-1 is a schematic diagram of a projection imaging process of a projection lens provided by an embodiment of the present application.
  • the implementation environment may include a projection screen 10 and a projection lens 20.
  • the projection lens 20 can project an image beam to the projection screen 10, and the image beam can form an image on the screen 10.
  • the current development trend is to reduce the projection ratio of the projection lens 20 (the projection ratio is the ratio of the projection distance s to the diagonal length of the screen h, and the projection distance s is the lateral distance between the projection lens 20 and the projection screen 10).
  • the laser projection device can be set closer to the wall (the plane where the projection screen is located), instead of having to reserve enough distance for imaging like a telephoto lens, and the projection lens 20 can be within a short projection distance
  • the projection device host and the screen tend to be an integrated device.
  • the above-mentioned projection lens with relatively small projection can be referred to as a short-focus or ultra-short-focus projection lens.
  • a projection lens with a relatively small projection will have various aberrations such as distortion (English: Distortion), astigmatism (English: Astigmatism), field curvature (English: Field Curvature), and coma (English: Coma).
  • distortion English: Distortion
  • astigmatism English: Astigmatism
  • field curvature English: Field Curvature
  • coma International: Coma
  • the projection lens in the related technology has a large number of lenses (usually more than 16 or about 20) and various types, which in turn makes the system structure complex, the length of the system is not easy to shrink, the manufacturability is low, and the cost is low. hard to control.
  • the embodiments of the present application provide a projection lens and a laser projection device, which can solve the above-mentioned problems in the related art.
  • Figure 1-2 provides a schematic diagram of the optical engine structure of a laser projection device, including a light source 100, an optical engine 200, and a lens 300, which are connected in sequence to form the core optical system of the laser projection device.
  • the light source 100 currently uses a laser light source to provide an illuminating light beam.
  • the illuminating light beam can be white light or three-primary light with sequential output.
  • the core component in the optical engine 200 is a light valve, which is a light modulation device.
  • the types of light valves are also different.
  • the light valve is a liquid crystal light valve
  • the light valve is a DMD digital micro-mirror array.
  • the embodiments all use the DLP projection architecture as an example for description, in which the light valve component is a DMD digital micromirror array chip.
  • the size of the light valve is small, and the illuminating light beam usually needs to be reshaped by the illuminating light path before irradiating the light valve to meet the requirements of the light valve surface for the incident angle and shape of the light beam.
  • the driving signal corresponding to the image display signal the light valve completes the modulation of the illumination beam by controlling the luminous flux, and then forms a colorful picture after imaging and magnification. It can be seen that the light valve is also the core component of the entire projection system, and the resolution of the light valve can determine the resolution of the projection screen.
  • DMD projects the modulated light beam into the projection lens.
  • the central vertical line of the light reflection surface (also the light incident surface) of the DMD is the light that is oblique to the projection lens. Shaft. This offset setting also finally ensures that the projected image beam is also projected on the projection screen in an oblique manner after passing through the projection lens, as shown in Figure 1-1.
  • the projection lens 300 is an ultra-short throw projection lens, which makes the light beam propagate forward along the main optical axis of the lens, and is finally reflected and projected on the projection screen in an oblique upward direction.
  • the direction of beam propagation has been turned less than 90 degrees.
  • an embodiment of the present application also provides a laser projection device, including a light source 40, a light valve 30, a screen 10, and the projection lens 20 provided in the above embodiment;
  • the light source 40 is used to provide a laser beam to the light valve 30;
  • the light valve 30 is used for modulating the laser beam provided by the light source 40 and then emitted to the projection lens 20;
  • the projection lens 20 is used for imaging the laser beam provided by the light valve 30 and then emitted to the screen 10.
  • the above-mentioned laser projection device is an ultra-short throw laser projection device, and the offset of the pixel plane of the light valve relative to the optical axis of the projection lens is 135% to 150%.
  • the above-mentioned projection lens is an ultra-short throw projection lens.
  • Fig. 7 shows a schematic diagram of the internal optical path of a projection lens in the above-mentioned laser projection equipment. It can be seen from the figure that the projection lens includes a refraction lens group and a reflection mirror group, wherein a first aspheric lens is arranged in the refraction lens group close to the light valve, and a second aspheric lens is arranged close to the reflection mirror group, thereby A piece of aspherical lens is respectively arranged at the front part and the rear part of the refracting lens group, and the lenses in the remaining refracting lens group are all spherical lenses.
  • a triplet lens at least one single lens, a double doublet lens, and three single lenses are arranged in sequence before the first aspheric lens and the second aspheric lens. Two single lenses can be set between the lenses.
  • the refractive lens group and the mirror group satisfy: 0.2 ⁇ L2/L1 ⁇ 0.5, where L1 is the length of the refractive lens group, and the L2 is the distance between the refractive lens group and the mirror group
  • L1 is the length of the refractive lens group
  • L2 is the distance between the refractive lens group and the mirror group
  • the refracting lens group 21 of the above-mentioned ultra-short throw projection lens includes 13 lens lenses, among which the second lens 1b arranged in the light emitting direction is an aspheric lens, and the third lens 1c and the fifth lens 1e are respectively Laminated on both sides of the fourth lens 1d to form a triplet lens.
  • the 8th lens 1h and the 9th lens 1j are bonded to each other to form a doublet lens.
  • the thirteenth lens 3c is an aspheric lens, and the rest are spherical lenses. Aspheric lens can be used to correct the astigmatism and coma of the system
  • the quotient of the dispersion coefficients of the first lens and the third lens satisfies [0.6, 1.5].
  • the quotient of the dispersion coefficients of the first lens and the second lens satisfies [0.85, 1.2].
  • a single-lens lens between the triplet lens and the doublet lens specifically, the sixth lens 1f has a refractive index greater than or equal to 1.75 and a dispersion coefficient less than or equal to 25.
  • the diaphragm is arranged between the triplet and doublet lens so as to be located in the front position of the refractive lens group.
  • the above-mentioned ultra-short throw projection lens includes a refracting lens group and a reflecting mirror group.
  • an aspheric lens is respectively arranged at the front and rear of the lens group, and a triplet lens and a single lens are also arranged between the aspheric lenses.
  • the rear part of the refractor group is close to the mirror group with aspherical lenses, which is farther from the diaphragm and has a larger field of view.
  • the mirror group of the above-mentioned ultra-short focal lens is a concave aspheric mirror, which cooperates with the aforementioned refracting mirror group to realize ultra-short focal projection imaging.
  • Figure 3-1 is an optical schematic diagram of a projection lens provided by an embodiment of the present application.
  • the projection lens receives the light beam emitted by the light valve, and is sequentially provided with a refraction lens group 21 and a reflection mirror 22 along the light exit direction.
  • the refracting lens group 21 is divided into a first lens group 211, a second lens group 212, and a third lens group 213 that are sequentially arranged along the light exit direction 5.
  • the first lens group 211 is the front group lens group of the projection lens, and the front group lens group first receives the modulated light beam and corrects the primary aberrations other than astigmatism and distortion of the modulated light beam.
  • the first lens group 211 includes an aspheric lens, a triplet lens, and a double cemented lens.
  • the triplet lens and the double cemented lens also include at least one single lens. In specific implementations, it may be two single lenses. Lens lens. And, the aspheric lenses are all located before the triplet lens and the doublet lens. The large positions of the triplet lens and doublet lens can be exchanged according to design needs.
  • the quotient of the dispersion coefficients of the first lens and the third lens satisfies [0.6, 1.5].
  • the quotient of the dispersion coefficients of the first lens and the second lens satisfies [0.85, 1.2].
  • a single-lens lens located between the triplet lens and the doublet lens and close to the triplet lens has a refractive index greater than or equal to 1.75, and a dispersion coefficient less than or equal to 25.
  • the first lens group 211 may include a second lens 1b, a third lens 1c, a fourth lens 1d, a fifth lens 1e, a sixth lens 1f,
  • the seventh lens 1g, the eighth lens 1h, and the ninth lens 1j, and the second lens 1b are aspherical lenses, which can be used to correct the astigmatism and coma of the system.
  • the third lens 1c and the fifth lens 1e are attached to both surfaces of the fourth lens 1d, respectively.
  • the eighth lens 1h and the ninth lens 1j are attached to each other (such a structure is shown in Figs. 3-1). That is, the third lens 1c, the fourth lens 1d, and the fifth lens 1e constitute a triplet lens, and the eighth lens 1h and the ninth lens 1j constitute a double cemented lens.
  • the triplet lens can correct aberrations such as spherical aberration, field curvature, and chromatic aberration of the system. It is adjacent to the aspheric lens 1b, and can control the aberration of the system to a large extent.
  • the double cemented lens can be used to correct the spherical aberration and chromatic aberration of the system, and can be made of materials with small dispersion coefficients to compensate for the chromatic aberration caused by the sixth lens and the seventh lens.
  • the dispersion coefficient is also called Abbe number (English: Abbe) is a physical quantity used to measure the degree of light dispersion of the medium. The greater the refractive index of the material, the stronger the dispersion and the smaller the Abbe number.
  • the ratio of the dispersion coefficient of the eighth lens 1h to the dispersion coefficient of the ninth lens 1j satisfies [0.85, 1.2].
  • the lenses in the above-mentioned first lens group 211 are all glass lenses, which can withstand high temperatures when irradiated by high-energy modulated beams for a long time, and are not prone to surface changes, so that the optical confinement ability is more stable, and the imaging stability is also ensured .
  • the refractive powers of the first lens, the second lens, the third lens, the sixth lens, and the seventh lens are positive, and the fourth lens, the fifth lens, and the eighth lens And the refractive power of the 9th lens is negative.
  • the diaphragm of the projection lens is provided between the 8th lens and the 5th lens.
  • the second lens group 212 includes a spherical lens, which is mainly used to adjust the projection size of the projection lens. In a specific implementation, for example, a size enlargement change of 80 to 100 inches is realized.
  • the refractive power of the spherical lens is positive.
  • the third lens group 213 is mainly used for correcting distortion and astigmatism in cooperation with the mirror 22, and includes at least one aspheric lens, and the aspheric lens can be made of plastic.
  • the projection lens further includes a reflector group, specifically a reflector 22, located at the rear end of the optical axis of the projection lens, used to angle the beam of the refracting lens group while imaging, and the reflector may be a free-form surface reflection Mirror or concave aspheric mirror.
  • the projection lens provided by the embodiments of the present application includes a refracting lens group and a reflecting mirror.
  • the first lens group in the refracting lens group includes an aspheric lens, a triplet lens, two single lenses, and a doublet lens.
  • the aspheric lens is arranged before the triplet lens and the doublet lens.
  • the refracting lens group 21 and the reflecting mirror 22 satisfy the first formula, and the first formula is: 0.2 ⁇ L2/L1 ⁇ 0.5, L1 is the length of the refracting lens group 21, and L2 is The distance between the refracting mirror group 21 and the reflecting mirror 22.
  • the first mirror group 211, the second mirror group 212, and the third mirror group 213 satisfy the second formula, and the second formula is:
  • 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 212
  • FT is the equivalent focal length of the third lens group 213
  • FM is the equivalent focal length of the mirror 22.
  • the diaphragm is located in the first lens group, and the beams on both sides of the diaphragm position are basically symmetrical, which can help control the system aperture and shorten the length of the lens.
  • the light valve 30 is a digital micromirror device (English: Digital Micromirror Device; abbreviated as DMD), and the DMD can be 2K resolution or 3K resolution.
  • the light valve 30 includes a mirror array and a control circuit. When the light valve 30 receives light, the control circuit controls the mirror array to reflect the light beam emitted by the light source system to generate an image beam. How the light valve 30 specifically generates the image beam is related technology, and will not be repeated here.
  • Figure 3-2 shows a schematic diagram of a laser projection device provided by an embodiment of the present application.
  • a light valve 30, a total reflection prism 25, and a projection lens are included.
  • the projection lens includes a refraction lens group 21 and a reflection mirror 22.
  • the first lens group 211, the second lens group 212, the third lens group 213, and the reflecting mirror 22 in the above-mentioned projection lens are located on the same optical axis 6.
  • the mirror 22 is a free-form surface mirror or a concave aspheric mirror.
  • the projection lens can be a rotationally symmetric system, which can reduce the processing difficulty of the lens, and is easy to realize generalization and reduce costs.
  • the light valve 30 is a DMD digital micro-mirror chip, and a total reflection prism 25 is also provided between the light valve 30 and the first mirror group 211.
  • the total reflection prism 25 is a TIR total reflection prism, including two cemented total reflection prisms, namely a first total reflection prism (not shown in the figure) and a second total reflection prism (not shown in the figure).
  • the light beam directed to the surface of the light valve 30 first strikes a side surface of the first total reflection prism, and is totally reflected on a hypotenuse surface of the first total reflection prism, and the totally reflected light beam is directed to the light valve.
  • the light valve 30 When the totally reflected light beam is directed to the light valve 30, the light valve 30 reflects the light beam and generates an image light beam, and then the generated image light beam is directed from the light valve 30 to the second total reflection prism, the image light beam does not undergo total reflection, and It directly projects the image beam output to the projection lens.
  • a total reflection prism can be used to reflect the light beam to the light valve 30, which eliminates the need for multiple reflections through multiple ordinary mirrors, thereby reducing The number of ordinary mirrors used has greatly reduced the volume of the projection lens; in addition, the total reflection prism 25 makes the light beam passing through it become a uniform light beam parallel to the optical axis 6, thus meeting the needs of the telecentric optical path. The image beam generated by the valve 30 becomes uniform, thereby also improving the quality of the projected image.
  • the aspheric lens provided in the first lens group 211 functions to first perform astigmatism and coma on the light beam.
  • the first lens of the first lens group 211 is the closest to the light valve 30 and is a sensitive position. It mainly collects light and is usually not set as an aspheric lens, but as a spherical lens.
  • the first lens group 211 includes a first lens 1a, a second lens 1b, a third lens 1c, a fourth lens 1d, a fifth lens 1e, a sixth lens 1f and a
  • the seventh lens 1g, the eighth lens 1h, the ninth lens 1j, and the second lens 1b are aspherical lenses that can be used to correct the astigmatism and coma of the system. All lenses in the first lens group 211 except for the second lens 1b are spherical lenses. In this way, the number of aspheric lenses can be minimized, and the cost and manufacturing difficulty can be reduced.
  • the first lens group 211 can be used to correct aberrations other than astigmatism and distortion.
  • the second lens 1b uses a material with a lower refractive index and a low melting point, such as L-BSL7, D-K59, L-BAL42 (L-BSL7, D-K59, and L-BAL42 are the three optical materials Model), to achieve lower cost non-curved surface processing and manufacturing.
  • a material with a lower refractive index and a low melting point such as L-BSL7, D-K59, L-BAL42 (L-BSL7, D-K59, and L-BAL42 are the three optical materials Model), to achieve lower cost non-curved surface processing and manufacturing.
  • the doublet lens formed by the eighth lens 1h and the ninth lens 1j may cooperate with the triplet formed by the third lens 1c, the fourth lens 1d and the fifth lens 1e to correct the chromatic aberration of the system.
  • the position of the triplet lens can be interchanged with the position of the doublet lens, that is, the seventh lens and the ninth lens are attached to both sides of the eighth lens, and the third lens and the fourth lens are attached to each other .
  • the refractive powers of the first lens, the second lens, the third lens, the sixth lens, and the seventh lens are positive, and the refractive powers of the fourth lens, the fifth lens, the eighth lens, and the ninth lens are negative.
  • the projection lens further includes a diaphragm 23, which is arranged between the eighth lens 1h and the fifth lens 1e. This can facilitate the correction of aberrations and control the system aperture.
  • the first lens group 211 can move along the light emitting direction or the opposite direction of the light emitting direction. That is, the first lens group can move back and forth along the optical axis 6 to adjust the imaging quality of the system to compensate for system tolerances and ensure the imaging quality of the system.
  • the first lens group 211 as a whole may be sliding movement, or may be screw rotation movement. And because the system adopts a rotationally symmetric system, it is also convenient to realize the thread rotation movement without affecting the imaging quality.
  • the material of the lenses in the first lens group 211 may be glass to improve the ability of the first lens group 211 to resist thermal deformation and avoid the problem of deterioration of image quality due to thermal deformation.
  • the second lens group 212 includes a tenth lens 2a, and the tenth lens 2a is a spherical lens.
  • the tenth lens 2a can move along the light emitting direction 5 or the opposite direction of the light emitting direction 5.
  • the third lens group 213 includes an 11th lens 3a, a 12th lens 3b, and a 13th lens 3c, the 11th lens 3a and the 12th lens 3b are spherical lenses, and the 13th lens 3c is an aspheric lens.
  • the thirteenth lens 3c can be made of plastic to reduce the manufacturing difficulty.
  • the 13th lens 3c is farther from the diaphragm 23 and has a larger field of view. Setting it as an aspheric lens can better correct the distortion of the system imaging and has a better correction effect on astigmatism.
  • the reflector 22 may be a concave aspheric reflector or a free-form surface reflector.
  • the distance between the mirror 22 and the last lens of the third lens group 213 (that is, the 13th lens 3c) is L2.
  • L2 is a fixed value.
  • L2 also changes slightly. Compensation to achieve clear imaging with different projection sizes, and the range of L2 variation satisfies
  • the light valve 30 adopts a telecentric illumination system, and the projection lens is also a telecentric lens.
  • the advantage of using telecentricity in the system is that the light beam from the light valve 30 is incident on the projection lens as a parallel beam, and the uniformity of the parallel beam is good, which is also beneficial to ensure the brightness uniformity of the projection image.
  • the laser projection device in this example is compared with the example in Figure 3-2, and a vibrating lens is also provided between the light valve 30 and the projection lens. twenty four.
  • the vibrating lens is arranged between the light valve 30 and the refractive lens group 21.
  • the vibrating lens 24 is a flat plate structure that is driven to vibrate at a high frequency.
  • the light beam output by the total reflection prism 25 first passes through the vibrating lens 24 and then is directed to the projection lens.
  • the vibration of the vibrating lens 24 makes the image light beams corresponding to two adjacent frames of projected images passing through the vibrating lens not completely overlap, and the image light beams corresponding to the two adjacent frames of projection images are directed to the refracting lens group in turn, and the projected image is the image light beam passing through the projection lens After the image presented on the projection screen.
  • the vibrating lens 24 is flat glass.
  • the vibrating lens 24 can vibrate.
  • the vibration of the vibrating lens 24 makes the image beams corresponding to two adjacent frames of the projected image passing through the vibrating lens 24 not completely overlap, so that the image beams directed to the same pixel increase, thereby improving the imaging resolution, and due to vibration
  • the vibration of the lens 24 makes the image beams corresponding to the two adjacent frames of projected images slightly staggered, thereby making the transition between pixels smoother, thereby increasing the details of the picture, visually improving the clarity of the picture, and improving the image quality.
  • the effect of the persistence of human vision, as far as the user is concerned, the resolution of the picture he is watching has been improved, which has the effect of "doubled" the resolution.
  • the two sub-pictures are displayed in a misaligned superposition.
  • the four sub-pictures are superimposed and displayed in a dislocation. Achieve a double or quadruple increase in the resolution of visual effects.
  • the back focus of the first lens group 211 is within the preset range, and the back focus refers to the distance between the light exit surface of the light valve and the first lens of the projection lens (that is, the first lens of the first lens group).
  • the physical distance from the light valve 30 to the first lens 1a is the back focal length (English: Back Focus Length; abbreviated as BFL), and the BFL satisfies 18mm ⁇ BFL ⁇ 33mm.
  • the laser projection equipment shown in FIGS. 3-2 and 3-3 adopts a secondary imaging architecture. After the image beam of the light valve 30 passes through the refraction lens group 21, the first step is performed between the mirror 22 and the refraction lens group 21. Secondary imaging, after the first imaging is reflected by the mirror 22, a secondary distortion-free image is formed on the screen; the projection lens provided by the embodiment of the application is compact as a whole, and the diaphragm is set on the aspheric lens and the mirror pair is large. The correction of the field of view aberration improves the resolution capability of the projection lens, thereby achieving high-resolution imaging quality.
  • the effective focal length (English: Effective Focal Length) of the projection lens shown in Figure 3-2 and Figure 3-3 is -2.09 millimeters (mm), and the offset (the offset is the distance between the light valve pixel surface and the optical axis Offset, English: offset) is 135% to 150%, the projection range is 60 to 100 inches, the throw ratio is less than 0.25, the focal length is between 1.8 and 2.3, and the telecentricity is ⁇ 1°.
  • the resolution capacity can reach 93lp/mm (lp/mm is line pair/mm, which is a resolution unit).
  • the distance between the different lenses and lens groups involved in some embodiments of the present application is the distance on the optical axis 6.
  • the first lens group 211 of the projection lens is a non-fixed lens group, that is, the rear group lens group can be a dynamic group, specifically, it can move in the light emitting direction or the opposite of the light emitting direction. , Used to compensate system tolerances.
  • the second lens group 212 can move in the light-emitting direction or the opposite direction of the light-emitting direction to adjust the projection size of the projection lens to ensure that the image is still clear under different projection sizes. Therefore, the second lens group 212 is also It can be a dynamic group, and the middle group mirror group is a dynamic group.
  • the third lens group 213 is usually set as a fixed group, and the last lens of the third lens group 213 is usually fixed relative to the mirror 22.
  • the third mirror group 213 is used to cooperate with the mirror 22 to correct the distortion of the system and the astigmatism of the system.
  • the distance between the mirror 22 and the last lens of the third lens group 213 is L2.
  • L2 is a fixed value.
  • L2 can also be changed within a preset range to match the second lens group 212 Compensation to achieve clear imaging with different projection sizes, and the range of L2 variation satisfies
  • the effective focal length of the above-mentioned reflecting mirror 22 and the effective focal length of the refractive lens group satisfy: 5 ⁇
  • FIG. 8 is a schematic structural diagram of a cross-section (the cross-section may be a surface determined by the optical axis z) of another projection lens provided by an embodiment of the present application.
  • the projection lens is adjusted on the basis of the projection lens shown in FIG. 2.
  • the lens barrel 221 includes a main lens barrel A and a third lens barrel B, the main lens barrel A is fixedly connected to the base 21, and the third lens barrel B is fixedly connected to the base 21.
  • the first lens group 222 is movably connected with the main lens barrel A
  • the second lens group 223 is movably connected with the main lens barrel A
  • the third lens group 224 is fixedly connected with the third lens barrel B.
  • the lens barrel 221 further includes a curved tube C, a first lens barrel D, and at least one first adjustment mechanism (not shown in FIG. 8), and the first lens group 222 is located in the first lens barrel D.
  • the curved tube C is sleeved outside the main lens barrel A, the main lens tube A is sleeved outside the first lens barrel D, and the axes of the curved tube C, the main lens barrel A and the first lens barrel D are parallel to each other.
  • the lens barrel 221 includes a second lens barrel E and at least one second adjustment mechanism (not shown in FIG. 8), the main lens barrel A is sleeved outside the second lens barrel E, and the second lens barrel E The axis is parallel to the axis of the main barrel A.
  • the mirror group 23 is movably connected to the base 21 and can move along the length direction of the optical axis z.
  • the third lens barrel B is fixedly connected to the main lens barrel A.
  • FIG. 8 shows a specific structure of each lens in a projection lens, but the embodiment of the present application does not limit this.
  • adjusting the first lens group 222 along the length of the optical axis z can adjust the back focus (that is, the distance between the first lens group and the light valve), and the function of this adjustment may include adjusting the resolution of the entire picture.
  • the function of adjusting the second lens group 223 along the length of the optical axis z may include adjusting the resolution of the left and right upper corners of the picture, and slightly adjusting the overall distortion of the picture, such as adjusting a barrel-shaped picture into a rectangular picture.
  • the function of adjusting the mirror group 223 along the length of the optical axis z may include adjusting the overall distortion and resolution of the picture. Among them, move forward (make the reflector move in the direction close to the refracting lens group).
  • the reflector group can compensate the screen resolution of the projection lens when the projected screen size is 70-100 inches, and move backward (make the reflector move away from the refracting lens group).
  • the mirror group can compensate the screen resolution of the projection lens when the projection screen size is 60-100 inches.
  • the mirror group is pre-adjusted to the theoretical design position, the frame of the picture is straight, and there is no cylindrical and pillow-shaped distortion, and then the first mirror group and the second mirror group are adjusted.
  • the light source, the light valve, and the projection lens are the core optical imaging system, and the projection lens can achieve a higher display effect.
  • FIG. 4 it is a schematic diagram of aberrations of red light, blue light, and green light at the 0.16 field of view of the projection lens provided by the embodiment of the application.
  • Py is the meridian direction of the pupil
  • Px is the sagittal direction of the pupil
  • ex is the aberration in the sagittal direction
  • ey is the aberration in the tangential direction.
  • FIG. 5 which is the red light of the projection lens provided by the embodiment of the application at 0.7 field of view
  • FIG. 5 Schematic diagram of aberrations of blue light and green light. The meanings of other marks in Fig.
  • FIG. 6 it is a schematic diagram of aberrations of red light, blue light, and green light at the 1.0 field of view of the projection lens provided by the embodiment of the application. The meaning of other marks in FIG. 6 can be referred to FIG. 4, which will not be repeated here.
  • the laser projection equipment provided in the above embodiments adopts a telecentric system, and the light valve projects a parallel beam into the projection lens.
  • the projection lens has a sufficient back focus length to accommodate a total reflection prism, or a total reflection prism and a vibrating lens, to achieve Good accommodation and cooperation of the light valve.
  • the above-mentioned projection lens can also realize the optimization of the number of lenses through the combination of mirrors, which greatly reduces the number of lenses.
  • the refractive lens group is provided with an aspheric lens at the front and rear of the lens group, and a combination of three cemented lenses, single lens lenses, and double cemented lenses is also set between the aspheric lenses, so that the refractive lens group
  • the front-end part assumes the ability to correct primary aberrations, which can reduce the design difficulty and number of rear-end lenses, and reduce the number of lenses in the overall projection lens.
  • the refractive lens group is provided with an aspheric lens at the front and rear of the lens group, and a combination of a triplet lens, a single lens lens, and a doublet lens is also provided between the aspheric lenses.
  • the front part of the refractor group assumes the ability to correct primary aberrations, which can reduce the design difficulty and number of rear lenses, and reduce the number of lenses of the overall projection lens. Setting the diaphragm between the two cemented lens groups of the refracting lens group, close to the front end of the refracting lens group, can better control the system aperture and also facilitate the simplification of the number of lenses.
  • the rear part of the refractor group is close to the mirror group with aspherical lenses, which is farther from the diaphragm and has a larger field of view. It can better cooperate with the mirror group to correct the distortion of the system imaging and also help reduce the lens. quantity.
  • the first lens group and the second lens group are set as movable groups, and the distance between the mirror and the third lens group is fine-tuned to achieve ultra-short focus and high definition.
  • the adjustment of the projection size under the requirements of high-degree projection is applicable to a wider range of projection requirements.
  • the laser projection equipment provided in this application can meet the high-resolution requirements and achieve the reduction in the number of projection lens lenses.
  • the length of the lens is shortened, which can promote the optimization of the optical system arrangement, and the volume of the laser projection equipment itself is also conducive to compression Realize miniaturization and have high product application value.

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Abstract

本申请公开了一种激光投影设备，投影镜头具有较少的镜片数量，且能够实现高解析度要求，利于实现产品体积的小型化。

Description

激光投影设备
本申请要求于2019年3月20日提交中国专利局、申请号为201910212856.8，申请名称为“投影镜头及激光投影装置”的中国专利申请的优先权，以及，要求于2019年7月29日提交中国专利局、申请号为201910691196.6，申请名称为“投影镜头及激光投影装置”的中国专利申请的优先权，其全部内容通过引用结合在本申请中。
技术领域
本申请涉及光学设备领域，特别涉及一种激光投影设备。
背景技术
随着科学技术的提高，随着家用投影设备的应用，比如激光超短焦投影设备，能够在贴墙状态下为用户呈现大尺寸，高清晰度、高色域范围和亮度的画面，其中，呈现上述高品质的画面不仅因为应用了激光作为光源，具有高解析能力的超短焦镜头也是激光投影设备的重要组成部分。投影镜头解析能力越高，用户观影体验越高。
在镜头设计过程中，需要兼顾多方面的需求。比如投影镜头需要配合照明系统来设计，照明系统分为远心照明系统和非远心照明系统，则投影镜头也分别对应设计成远心投影镜头和非远心投影镜头，在光束的接收和约束能力也具有不同。
以及，通常投影镜头解析能力的提高使得镜片的使用数量增加，镜片面型的设计难度较大。
即为了能实现较高的分辨率以及较短的焦距，投影镜头中透镜的组合通常 较为复杂。进而导致投影镜头整体结构较为复杂，而不利于镜头体积的缩小，而投影镜头的体积约占到投影设备光学引擎的三分之一以上，这也会使得整个激光投影设备的体积难以缩小，使设备显得笨重。
发明内容
本申请实施例提供了一种激光投影设备，利于实现光学结构的简化和设备体积的压缩。为实现上述技术目的，采用的技术方案如下：
提供了一种激光投影设备，包括光源，光阀和投影镜头，
其中，光源用于向光阀提供激光光束；光阀用于将光源提供的激光光束调制后出射至投影镜头；投影镜头用于将光阀提供的激光光束成像后出射至投影屏幕；
其中，光阀像素面相对投影镜头光轴的偏移量为135％至150％，
投影镜头包括折射镜组和反射镜组，折射镜组中靠近光阀设置有第一非球面透镜，以及，靠近反射镜组设置有第二非球面透镜；其余折射镜组中的透镜均为球面透镜；
折射镜组中在第一非球面透镜和第二非球面透镜之前还依次设置有一三胶合透镜、至少一片单透镜、一双胶合透镜、三片单透镜；
折射镜组和反射镜组满足：0.2≤L2/L1≤0.5，其中，L1为折射镜组的长度，L2为折射镜组和反射镜组之间的间距。
本申请实施例提供的技术方案带来的有益效果至少包括：
上述激光投影设备中，投影镜头包括折射镜组和反射镜组，折射镜组中分别在镜组的前部和后部各设置了一片非球面透镜，在非球面透镜之间还设置有 三胶合透镜、单透镜镜片、双胶合透镜的组合，从而一方面折射镜组前端部分承担了对初级像差的校正能力，能够降低后端镜片的设计难度和数量，整体投影镜头的镜片数量减少。以及，另一方面，折射镜组的后部靠近反射镜组设置非球面镜片，与光阑距离较远，视场较大，能够更好的配合反射镜组进行矫正系统成像的畸变，也利于减少镜片的数量。
从而，上述激光投影设备中的投影镜头，相比于相关技术中，实现高解析度超短焦投影的相同前提下，其镜片数量少，镜组分工高效，使得投影镜头部分可以从体积上得到压缩，并且镜组设计简洁，复杂度降低，上述投影镜头采用的非球面透镜数量少，也利于投影镜头成本的下降以及良率的提升，激光投影设备本身也相应具有上述的有益效果。
附图说明
为了更清楚地说明本申请实施例中的技术方案，下面将对实施例描述中所需要使用的附图作简单地介绍，显而易见地，下面描述中的附图仅仅是本申请的一些实施例，对于本领域普通技术人员来讲，在不付出创造性劳动的前提下，还可以根据这些附图获得其他的附图。
图1‐1是本申请实施例所提供的一种投影镜头投影成像过程的示意图；
图1‐2是本申请实施例提供的一种激光投影设备光学引擎结构示意图；
图2是本申请实施例提供的一种激光投影设备示意图。
图3‐1是本申请实施例提供的一种激光投影设备光学示意图；
图3‐2是本申请实施例提供的又一种激光投影设备光学示意图；
图3‐3是本申请实施例提供的再一种激光投影设备光学示意图；
图4是本申请实施例提供的投影镜头的一种像差示意图；
图5是本申请实施例提供的投影镜头的一种像差示意图；
图6是本申请实施例提供的投影镜头的一种像差示意图；
图7是图2所示的激光投影设备中一种投影镜头的光路示意图；
图8是图2所示的激光投影设备中一种投影镜头的结构示意图。
通过上述附图，已示出本申请明确的实施例，后文中将有更详细的描述。这些附图和文字描述并不是为了通过任何方式限制本申请构思的范围，而是通过参考特定实施例为本领域技术人员说明本申请的概念。
具体实施方式
为使本申请的目的、技术方案和优点更加清楚，下面将结合附图对本申请实施方式作进一步地详细描述。
图1‐1是本申请实施例所提供的一种投影镜头投影成像过程的的示意图，实施环境可以包括投影屏幕10和投影镜头20。
投影镜头20可以向投影屏幕10投射影像光束，该影像光束能够在屏幕10上形成图像。目前的发展趋势是降低投影镜头20的投射比(投射比是投影距离s和画面对角线长度h的比值，投影距离s为投影镜头20和投影屏幕10之间的横向距离)，投射比越小，激光投影设备就可以更近靠近墙体(投影屏幕所在的平面)设置，而不必像长焦镜头一样，必须预留足够的距离才能成像，而投影镜头20能够在很短的投影距离内就投射出较大尺寸的画面，投影设备主机和屏幕也更倾向于是一体的设备。上述投射比较小的投影镜头可以称为短焦或超短焦的投影镜头。
但是，投射比较小的投影镜头会出现如畸变(英文：Distortion)、像散(英文：Astigmatism)、场曲(英文：Field Curvature)、慧差(英文：Coma)等各种像差。为了克服这些像差，相关技术中的投影镜头的透镜数量多(通常在16个以上，20个左右)、种类多，进而使得系统结构复杂，系统的长度也不易缩小，可制造性低，成本难以控制。
本申请实施例提供了一种投影镜头及激光投影设备，能够解决上述相关技术中存在的问题。
图1‐2提供了一种激光投影设备的光学引擎结构示意图，包括光源100，光机200，镜头300，三者依次连接，构成激光投影设备核心的光学系统。其中，光源100目前采用激光光源，用于提供照明光束，照明光束可以是白光，也可以是时序输出的三基色光，光机200中的核心部件为光阀，光阀是一种光调制器件，根据投影架构的不同，光阀的种类也不同，比如在LCOS投影架构中，光阀为液晶光阀，在DLP投影架构中，光阀为DMD数字微镜阵列，以下本申请提供的多个实施例均采用DLP投影架构为例进行说明，其中的光阀部件为DMD数字微镜阵列芯片。光阀的尺寸较小，照明光束在照射到光阀之前通常还需要经过照明光路的整形，以符合光阀表面对光束的入射角度和形状的要求。光阀根据图像显示信号对应的驱动信号，通过对光通量的控制来完成对照明光束的调制，进而经过成像放大后形成彩色的画面。可见，光阀也是整个投影系统的核心部件，光阀的分辨率可以决定投影画面的分辨率。
DMD作为一种反射式光阀，其将调制后的光束投射入投影镜头，在超短焦投影系统中，DMD的光反射面(也是光入射面)的中心垂线是偏执于投影镜头的光轴的。这种偏置设置也最终保证了投影影像光束经过投影镜头后也是以斜 向上的方式投影到投影屏幕上，如图1‐1所示。
投影镜头300为超短焦投影镜头，这使得光束沿着镜头的主光轴向前传播，而最终被反射，呈斜向上方向投射到投影屏幕上。光束传播方向发生了小于90度的转折。
如图2所示，本申请实施例还提供一种激光投影设备，包括光源40、光阀30、屏幕10以及上述实施例提供的投影镜头20；光源40用于向光阀30提供激光光束；光阀30用于将光源40提供的激光光束调制后出射至投影镜头20；投影镜头20用于将光阀30提供的激光光束成像后出射至屏幕10。
上述激光投影设备为超短焦激光投影设备，所述光阀像素面相对所述投影镜头光轴的偏移量为135％至150％。
上述投影镜头为超短焦投影镜头。图7示出了上述激光投影设备中一种投影镜头的内部光路示意图。从图中可知，投影镜头包括折射镜组和反射镜组，其中，折射镜组中靠近所述光阀设置有第一非球面透镜，以及，靠近反射镜组设置有第二非球面透镜，从而在折射镜组的前部和后部分别设置有一片非球面透镜，而其余折射镜组中的透镜均为球面透镜。
以及，折射镜组中在第一非球面透镜和第二非球面透镜之前还依次设置有一三胶合透镜、至少一片单透镜、一双胶合透镜、三片单透镜，其中，三胶合透镜和双胶合透镜之间可以设置两片单透镜。
上述超短焦投影镜头中，折射镜组和反射镜组满足：0.2≤L2/L1≤0.5，其中，L1为所述折射镜组的长度，所述L2为折射镜组和反射镜组之间的间距，上述超短焦投影镜头中折射镜组的透镜数量少，折射镜组和反射镜组构成的投影镜头的长度较短。
如图7所示，上述超短焦投影镜头的折射镜组21包括13片透镜镜片，其中，其中出光方向依次设置的第2透镜1b为非球面透镜，第3透镜1c和第5透镜1e分别贴合在第4透镜1d的两面，组成三胶合透镜，第8透镜1h、第9透镜1j互相贴合组成双胶合透镜，第13片透镜3c为非球面透镜，其余均为球面镜片。非球面透镜可以用于矫正系统的像散和彗差
其中，三胶合透镜中，第一片透镜与第三片透镜的色散系数的商满足[0.6，1.5]。
上述双胶合透镜中，第一片透镜与第二片透镜的色散系数的商满足[0.85，1.2]。
以及，三胶合透镜和双胶合透镜之间的一单透镜镜片，具体地，是第6透镜1f的折射率大于或等于1.75，色散系数小于或等于25。
以及，上述超短焦投影镜头中，光阑设置在三胶合和双胶合透镜之间，从而位于折射镜组靠前的位置中。
上述超短焦投影镜头包括折射镜组和反射镜组，折射镜组中分别在镜组的前部和后部各设置了一片非球面透镜，在非球面透镜之间还设置有三胶合透镜、单透镜镜片、双胶合透镜的组合，从而折射镜组前端部分承担了对初级像差的校正能力，能够降低后端镜片的设计难度和数量，整体投影镜头的镜片数量减少。以及，折射镜组的后部靠近反射镜组设置非球面镜片，与光阑距离较远，视场较大，能够更好的配合反射镜组进行矫正系统成像的畸变，也利于减少镜片的数量。上述超短焦镜头的反射镜组为一片凹面非球面反射镜，与前述折射镜组配合实现超短焦投影成像。
图3‐1是本申请实施例提供的一种投影镜头的光学示意图，该投影镜头接收 光阀出射的光束，沿着出光方向依次设置有折射镜组21和反射镜22。
为了便于理解，将折射镜组21划分为沿出光方向5依次设置的第一镜组211、第二镜组212和第三镜组213。
其中，第一镜组211为投影镜头的前群镜组，前群镜组最先接收到调制光束，并对调制光束进行矫正除像散、畸变之外的初级像差。
第一镜组211中包括一非球面透镜，一三胶合透镜，一双胶合透镜，其中三胶合透镜和双胶合透镜之间还包括至少一单透镜镜片，在具体实施中，可以为两片单片透镜镜片。以及，非球面透镜均位于三胶合透镜、双胶合透镜之前。三胶合透镜和双胶合透镜大的位置可以根据设计需要调换。
以及，在上述的三胶合透镜中，第一片透镜与第三片透镜的色散系数的商满足[0.6，1.5]。
上述的双胶合透镜中，第一片透镜与第二片透镜的色散系数的商满足[0.85，1.2]。
以及，位于三胶合透镜和双胶合透镜之间的、且靠近三胶合透镜的一单透镜镜片的折射率大于或等于1.75，色散系数小于或等于25。
具体地，请见图3‐1中，第一镜组211可以包括沿出光方向5依次设置的第2透镜1b、第3透镜1c、第4透镜1d、第5透镜1e、第6透镜1f、第7透镜1g、第8透镜1h和第9透镜1j，第2透镜1b为非球面透镜，可以用于矫正系统的像散和彗差。
第3透镜1c和第5透镜1e分别贴合在第4透镜1d的两面。第8透镜1h和第9透镜1j互相贴合(图3‐1示出的是此种结构)。也即是第3透镜1c、第4透镜1d和第5透镜1e构成了一个三胶合透镜，第8透镜1h和第9透镜1j构成 了一个双胶合透镜。该三胶合透镜可以对系统的球差、场曲、色差等像差进行校正，其与非球面透镜1b相邻，可以很大程度的控制系统的像差。双胶合透镜可以用于矫正系统的球差和色差，可以由色散系数差异较小的材料构成，以补偿第6透镜和第7透镜产生的色差。
第3透镜1c的色散系数与第5透镜1e的色散系数的商满足[0.6，1.5]，第6透镜1f的折射率大于或等于1.75，色散系数小于或等于25。其中，色散系数又称阿贝数(英文：Abbe)是用来衡量介质的光线色散程度的物理量。材料的折射率越大，色散越强，阿贝数越小。
第8透镜1h镜片的色散系数与第9透镜1j的色散系数的比值满足[0.85，1.2]。
上述第一镜组211中的镜片均为玻璃镜片，在长时间接收高能量调制光束的照射时能够耐高温，不易发生面型的改变，从而光学约束能力更为稳定，也保证了成像的稳定。
以及，上述第一镜组211中的9片透镜中，第1透镜、第2透镜、第3透镜、第6透镜和第7透镜的屈光度为正，第4透镜、第5透镜、第8透镜和第9透镜的屈光度为负。
以及，投影镜头的光阑设置在第8透镜和第5透镜之间。
第二镜组212包括一片球面镜片，主要用于调整投影镜头的投影尺寸，在具体实施中，比如实现80～100寸的尺寸放大变化。该球面镜片的光焦度为正。
第三镜组213主要用于与反射镜22配合校正畸变和像散，至少包括一片非球面镜片，非球面镜片可以采用塑胶材质。
以及，投影镜头还包括反射镜组，具体地为反射镜22，位于投影镜头的光轴后端，用于将折射镜组的光束进行角度转折的同时进行成像，上述反射镜可 以为自由曲面反射镜或者凹面非球面反射镜。
综上，本申请实施例提供的投影镜头，包括折射镜组和反射镜，折射镜组中的第一镜组包括了一个非球面镜、一个三胶合透镜、两个单透镜和一个双胶合透镜，且非球面镜设置于三胶合透镜和双胶合透镜之前。通过设置上述透镜组合，第一镜组能够对光束进行初级像差的校正，减轻了后端镜片的校正负担，利于降低镜片的设计难度，在实现超短焦高解析度画质投影的前提下，能够简化投影镜头的镜片数量和组合，利于投影镜头体积的压缩，并且也利于投影镜头生产的良率。
在一种投影镜头的示例中，可选地，折射镜组21和反射镜22满足第一公式，第一公式为：0.2≤L2/L1≤0.5，L1为折射镜组21的长度，L2为折射镜组21和反射镜22之间的间距。
第一镜组211、第二镜组212和第三镜213组满足第二公式，第二公式为：
Figure PCTCN2020079702-appb-000001
其中，F为折射镜组21的等效焦距，FB为第一镜组21的等效焦距，FS为第二镜组212的等效焦距，FT为第三镜组213的等效焦距，FM为反射镜22的等效焦距。
以及，在一种投影镜头的示例中，光阑位于第一镜组中，光束在光阑位置两侧的光束基本呈对称走向，可利于控制系统口径，并便于缩短镜头的长度。
以及，本示例中，光阀30是数字微镜元件(英文：Digital Micromirror Device；简称：DMD)，DMD可以是2K分辨率或3K分辨率。另外，光阀30包括反射镜 阵列和控制电路，当光阀30受到光照时，控制电路控制反射镜阵列反射光源系统发射出的光束，产生影像光束。有关光阀30如何具体产生影像光束为相关技术，在此不再赘述。
请参考图3‐2，其示出了本申请实施例提供的一种激光投影设备的示意图。在该图示中，包括光阀30，全反射棱镜25，以及投影镜头，投影镜头包括折射镜组21和反射镜22。
示例性地，上述投影镜头中的第一镜组211、第二镜组212、第三镜组213和反射镜22位于同一光轴6上。反射镜22为自由曲面反射镜或凹面非球面反射镜。
该投影镜头可以为旋转对称系统，可以降低镜片的加工难度，易于实现通用化和降低成本。
光阀30为DMD数字微镜芯片，在光阀30和第一镜组211之间还设置有全反射棱镜25。该全反射棱镜25为TIR全反射棱镜，包括两个胶合的全反射棱镜，分别为第一全反射棱镜(图中未示出)和第二全反射棱镜(图中未示出)。射向光阀30表面的光束，首先射向第一全反射棱镜的一个侧表面，并在第一全反射棱镜的一个斜边表面发生全反射，发生全反射后的光束射向光阀。当发生全反射后的光束射向光阀30时，光阀30反射光束并产生影像光束，然后将产生的影像光束从光阀30射向第二全反射棱镜，影像光束不发生全反射，而是直接将影像光束输出向投影镜头投射。
由于第一全反射棱镜使得射向其自身的光束发生全反射，因此使用一个全反射棱镜就可以将光束反射到光阀30上，从而不需要通过多个普通反射镜进行多次反射，进而减少了普通反射镜的使用数量，大大缩小了投影镜头的体积； 另外，全反射棱镜25使得通过其中的光束变为平行于光轴6均匀光束，因此，满足了远心光路的需求，由于使得光阀30产生的影像光束变得均匀，从而也提高投影图像的质量。
由于第一镜组211最靠近光阀30，当调制光束最先入射至第一镜组211中的镜片时，第一镜组211中设置的非球面透镜起到了首先对光束进行像散和彗差校正的作用。而第一透镜组211的第一片透镜距离光阀30最近，为敏感位置，其主要进行收光，通常不设置为非球面透镜，而设置为球面透镜。
因此，可选地，第一镜组211包括沿出光方向5依次设置的第1透镜1a、第2透镜1b、第3透镜1c、第4透镜1d、第5透镜1e、第6透镜1f、第7透镜1g、第8透镜1h和第9透镜1j，第2透镜1b为非球面透镜，可以用于矫正系统的像散和彗差。第一镜组211中除第2透镜1b外的透镜均为球面透镜。如此可以尽量减少非球面透镜的数量，降低成本和制造难度。第一镜组211可以用于矫正除像散、畸变之外的像差。
可选地，第2透镜1b使用折射率较低，且低熔点的材料，如L‐BSL7，D‐K59，L‐BAL42(L‐BSL7，D‐K59，L‐BAL42为三种光学材料的型号)，实现更低成本的非曲面面加工和制造。
可选地，第8透镜1h和第9透镜1j构成的双胶合透镜可以与第3透镜1c、第4透镜1d和第5透镜1e构成的三胶合透镜配合校正系统的色差。
可选地，三胶合透镜的位置还可以与双胶合透镜的位置互换，也即是第7透镜和第9透镜分别贴合在第8透镜的两面，第3透镜和第4透镜互相贴合。
可选地，第1透镜、第2透镜、第3透镜、第6透镜和第7透镜的屈光度为正，第4透镜、第5透镜、第8透镜和第9透镜的屈光度为负。
可选地，投影镜头还包括光阑23，光阑23设置在第8透镜1h与第5透镜1e之间。如此可以便于像差的校正，并控制系统口径。
以及，在一具体实施中，第一镜组211能够沿出光方向或出光方向的反方向移动。即第一镜组可以沿光轴6可以前后移动，实现对系统成像质量的调整，以补偿系统的公差保证系统成像质量。在具体实现调节移动时，第一镜组211作为整体可以为滑动移动，也可以为螺纹旋转移动。而由于系统采用旋转对称系统，也便于实现螺纹旋转移动，而不影响成像品质。
可选地，第一镜组211中镜片的材料可以均为玻璃，以提高第一镜组211抵抗热形变的能力，避免由于热形变导致的成像质量变差的问题。
以及，可选地，第二镜组212包括第10透镜2a，第10透镜2a为球面透镜。
可选地，第10透镜2a能够沿出光方向5或出光方向5的反方向移动。
可选地，第三镜组213包括第11透镜3a、第12透镜3b和第13透镜3c，第11透镜3a和第12透镜3b为球面透镜，第13透镜3c为非球面透镜。第13透镜3c可以由塑胶制成，以降低其制造难度。第13透镜3c与光阑23距离较远，视场较大，将其设置为非球面透镜能够更好的矫正系统成像的畸变，且对像散有较好的校正效果。
可选的，反射镜22可以为凹面非球面反射镜或自由曲面反射镜。反射镜22与第三镜组213最后一片透镜(即第13透镜3c)的间距为L2，固定投影尺寸下L2为固定值，投影尺寸变动时L2也随之轻微变动，与第二镜组212补偿，实现不同投影尺寸的清晰成像，L2变化范围满足|△L2|≤1mm。
上述激光投影设备中，光阀30采用远心照明系统，投影镜头也为远心镜头。系统中采用远心的优势在于，光阀30的出光光束是以平行光束入射至投影镜头 中，平行光束的均匀性佳，也利于保证投影画面的亮度均匀性。
在本申请提供的另一实施例中，如图3‐3所示，本示例中的激光投影设备与图3‐2中示例相比，在光阀30与投影镜头之间还设置了振动镜片24。振动镜片设置在光阀30和折射镜组21之间。
在本示例中，振动镜片24是一种受驱进行高频振动的平片结构。经全反射棱镜25输出的光束会先经过振动镜片24，再射向投影镜头。
振动镜片24振动使得经过振动镜片的相邻两帧投影图像对应的影像光束不完全重叠，并将相邻两帧投影图像对应的影像光束依次射向折射镜组，投影图像为影像光束经过投影镜头后在投影屏幕上呈现的图像。
比如振动镜片24为平板玻璃。振动镜片24能够振动，振动镜片24振动使得经过振动镜片24的相邻两帧投影图像对应的影像光束不完全重叠，使得射向同一像素的影像光束增加，进而提高成像的分辨率，而且由于振动镜片24的振动使得相邻两帧投影图像对应的影像光束略微错开，进而使得像素之间的过度更加平滑，从而增加画面的细节，从视觉上提高了画面的清晰度，进而提高成像质量，利用人眼视觉暂留的效应，对用户而言，其观看的画面实现了分辨率的提升，具有分辨率“倍增”的效果。
当振动镜片24在两个位置之间频繁振动时，是将两幅子画面进行错位叠加显示，当振动镜片24在四个位置之间频繁振动时，是将四幅子画面进行错位叠加显示，以实现视觉效果上的分辨率的二倍提升或四倍提升。
无论在图3‐2还是图3‐3所示的激光投影设备中，在光阀30和投影镜头的第一镜组之间均设置有光学元件。因此，第一镜组211的后焦在预设范围内， 后焦是指光阀的出光面与投影镜头第一片镜片(也即第一镜组的第一片镜片)之间的距离，以保证可以容纳全反射棱镜25，或者全反射棱镜25和振动镜片24。在本示例中，光阀30到第一透镜1a的物理距离为后焦距(英文：Back Focus Length；简称：BFL)，BFL满足18mm≤BFL≤33mm。
图3‐2和图3‐3所示的激光投影设备中采用为二次成像架构，光阀30的影像光束通过折射镜组21后，在反射镜22和折射镜组21之间进行第一次成像，第一次成像经反射镜22反射后，在屏幕上形成二次无畸变的图像；本申请实施例提供的投影镜头整体紧凑，通过光阑设置在、非球面透镜、反射镜对大视场像差的矫正，提高了投影镜头的解像能力，从而实现了高分辨率的成像质量。
图3‐2和图3‐3中所示的投影镜头的有效焦距(英文：Effective Focal Length)为‐2.09毫米(mm)，偏移量(该偏移量为光阀像素面相对光轴的偏移量，英文：offset)为135％至150％，投影范围为60至100寸，投射比小于0.25，焦距在1.8至2.3之间，远心度≤1°。解析能力可以达到93lp/mm(lp/mm为线对/毫米，是一种分辨率单位)。
需要说明的是，本申请一些实施例中所涉及不同透镜、镜组之间距离为在光轴6上的距离。
以及，在上述激光投影设备一示例中，投影镜头的第一镜组211为非固定镜组，即后群镜组可以为动组，具体地，可以沿出光方向或出光方向的反向进行移动，用于补偿系统公差。
以及，第二镜组212能够沿出光方向或出光方向的反方向移动，用于调整投影镜头的投影尺寸，保证在不同的投影尺寸下其成像仍然是清晰的，因此， 第二镜组212也可以为动组，及中群镜组为动组。
以及，第三镜组213通常设置为定组，第三镜组213的最后一片镜片通常相对于反射镜22固定。当第一镜组211和第二镜组212移动时，第三镜组213用以配合反射镜22矫正系统的畸变和系统的像散。
反射镜22与第三镜组213最后一片镜片的间距为L2，固定投影尺寸下L2为固定值，而当投影尺寸变动时L2也可以进行预设范围内的变动，以与第二镜组212补偿，实现不同投影尺寸的清晰成像，L2变化范围满足|△L2|≤1mm。上述反射镜22的有效焦距与折射镜组的有效焦距满足：5≤|FM/F|≤8，0.2≤|L2/L1|≤0.5。
具体地，图8是本申请实施例提供的另一种投影镜头的剖面(剖面可以为由光轴z确定的一个面)结构示意图。该投影镜头在图2所示的投影镜头的基础上进行了一些调整。
可选地，镜筒221包括主镜筒A和第三镜筒B，主镜筒A与底座21固定连接，第三镜筒B与底座21固定连接。
第一镜组222与主镜筒A可动连接，第二镜组223与主镜筒A可动连接，第三镜组224与第三镜筒B固定连接。
可选地，镜筒221还包括曲线筒C、第一镜筒D和至少一个第一调节机构(图8中未标出)，第一镜组222位于第一镜筒D中。
曲线筒C套在主镜筒A的外部，主镜筒A套在第一镜筒D外部，曲线筒C、主镜筒A以及第一镜筒D的轴线互相平行。
可选地，镜筒221包括第二镜筒E和至少一个个第二调节机构(图8中未标出)，主镜筒A套在第二镜筒E的外部，第二镜筒E的轴线与主镜筒A的轴线 平行。
可选地，反射镜组23与底座21可动连接，能够沿光轴z的长度方向移动。
可选地，第三镜筒B与主镜筒A固定连接。
图8示出了一种投影镜头中各个镜片的具体结构，但本申请实施例对此并不进行限制。其中，沿光轴z的长度方向调节第一镜组222可以调节后焦距(即第一镜组与光阀之间的距离)，该调节的作用可以包括调节整个画面的解析度。
沿光轴z的长度方向调节第二镜组223的作用可以包括调节画面的左右上角的解析度，并且微量调节画面的整体畸变，比如将桶形的画面调节成矩形的画面。
沿光轴z的长度方向调节反射镜组223的作用可以包括调节画面的整体畸变以及解析度。其中，前移(使反射镜沿靠近折射镜组的方向移动)反射镜组可以补偿投影镜头在投影画面尺寸为70‐100寸时的画面解析度，后移(使反射镜沿远离折射镜组的方向移动)反射镜组可以补偿投影镜头在投影画面尺寸为60‐100寸时的画面解析度。
一种调节方式中，反射镜组是预先调节到理论设计位置，画面边框正，无筒型和枕型畸变，之后调节第一镜组和第二镜组。
在上述一个或多个实施例提供的激光投影设备中，光源，光阀和投影镜头是核心的光学成像系统，上述投影镜头能够达到较高的显示效果。
如图4所示，其为本申请实施例提供的投影镜头在0.16视场处的红色光、蓝色光和绿色光的像差示意图。其中，Py表示为光瞳的子午方向，Px表示为光瞳的弧矢方向。ex为弧矢方向的像差，ey为子午方向的像差。(ex/ey值越小， 成像质量越高；ex/ey值越大，成像质量越差)，如图5所示，其为本申请实施例提供的投影镜头在0.7视场处的红色光、蓝色光和绿色光的像差示意图。图5中其他标记的含义可以参考图4，在此不再赘述。如图6所示，其为本申请实施例提供的投影镜头在1.0视场处的红色光、蓝色光和绿色光的像差示意图。图6中其他标记的含义可以参考图4，在此不再赘述。
由图4至图6可以看出，本申请实施例提供的投影镜头在图像各个位置的像差均能够达到较高的水平。
上述实施例中提供的激光投影设备采用远心系统，光阀以平行光束投射进入投影镜头，投影镜头具有足够的后焦长度，用于容纳全反射棱镜，或全反射棱镜和振动镜片，实现与光阀的良好容纳配合。以及，上述投影镜头还能够通过镜组合理搭配实现镜片数量的优化，大大减小了透镜的数量。其中，折射镜组中分别在镜组的前部和后部各设置了一片非球面透镜，在非球面透镜之间还设置有三胶合透镜、单透镜镜片、双胶合透镜的组合，从而折射镜组前端部分承担了对初级像差的校正能力，能够降低后端镜片的设计难度和数量，整体投影镜头的镜片数量减少。其中，折射镜组中分别在镜组的前部和后部各设置了一片非球面透镜，在非球面透镜之间还设置有三胶合透镜、单透镜镜片、双胶合透镜的组合，从而一方面，折射镜组前端部分承担了对初级像差的校正能力，能够降低后端镜片的设计难度和数量，整体投影镜头的镜片数量减少。将光阑设置于折射镜组的两个胶合透镜组之间，靠近折射镜组的前端，可以较好的控制系统口径，也利于镜片数量的简化。另一方面，折射镜组的后部靠近反射镜组设置非球面镜片，与光阑距离较远，视场较大，能够更好的配合反射镜组进 行矫正系统成像的畸变，也利于减少镜片的数量。
以及，在上述多个实例中，通过将第一镜组，第二镜组设置为可动组，以及，辅助以反射镜与第三镜组之间的距离微调方式，实现超短焦高清晰度投影要求下投影尺寸的调整，适用更广泛的投影要求。
综上，本申请提供激光投影设备能够达到高解析度的要求，并实现投影镜头镜片数量的减少，镜头长度得到了缩短，可以促进光学系统排布的优化，激光投影设备本身的体积也利于压缩实现小型化，具有较高的产品应用价值。
在本申请中，术语“第一”、“第二”、“第三”仅用于描述目的，而不能理解为指示或暗示相对重要性。术语“多个”指两个或两个以上，除非另有明确的限定。
以上仅为本申请的可选实施例，并不用以限制本申请，凡在本申请的精神和原则之内，所作的任何修改、等同替换、改进等，均应包含在本申请的保护范围之内。

Claims (18)

  1. 一种激光投影设备，其特征在于，包括光源，光阀和投影镜头，
    所述光源用于向所述光阀提供激光光束；
    所述光阀用于将所述光源提供的激光光束调制后出射至所述投影镜头；
    所述投影镜头用于将所述光阀提供的激光光束成像后出射至投影屏幕；
    其中，所述光阀像素面相对所述投影镜头光轴的偏移量为135％至150％，
    所述投影镜头包括折射镜组和反射镜组，所述折射镜组中靠近所述光阀设置有第一非球面透镜，以及，靠近所述反射镜组设置有第二非球面透镜；其余所述折射镜组中的透镜均为球面透镜；
    所述折射镜组中在所述第一非球面透镜和第二非球面透镜之前还依次设置有一三胶合透镜、至少一片单透镜、一双胶合透镜、三片单透镜；
    所述折射镜组和所述反射镜组满足：0.2≤L2/L1≤0.5，其中，L1为所述折射镜组的长度，所述L2为所述折射镜组和所述反射镜组之间的间距。
  2. 根据权利要求1所述的激光投影设备，其特征在于，
    所述折射镜组包括13片透镜，其中出光方向依次设置的第2透镜为非球面透镜，第3透镜、第4透镜、第5透镜组成三胶合透镜，第8透镜、第9透镜组成双胶合透镜，第13片透镜为非球面透镜。
  3. 根据权利要求1所述的激光投影设备，其特征在于，所述三胶合透镜中，第一片透镜与第三片透镜的色散系数的商满足[0.6，1.5]。
  4. 根据权利要求1所述的激光投影设备，其特征在于，所述双胶合透镜中，第一片透镜与第二片透镜的色散系数的商满足[0.85，1.2]。
  5. 根据权利要求1所述的激光投影设备，其特征在于，所述三胶合透镜和所述双胶合透镜之间的一单透镜镜片的折射率大于或等于1.75，色散系数小于或等于25。
  6. 根据权利要求2所述的激光投影设备，其特征在于，所述第1透镜、第2透镜、第3透镜、第6透镜和第7透镜的屈光度为正，所述第4透镜、第5透镜、第8透镜和第9透镜的屈光度为负。
  7. 根据权利要求1所述的激光投影设备，其特征在于，所述投影镜头还包括光阑，所述光阑设置在所述三胶合和双胶合透镜之间。
  8. 根据权利要求1‐7任一所述的激光投影设备，其特征在于，
    所述折射镜组包括沿光轴方向依次设置的第一镜组、第二镜组和第三镜组，所述第一镜组、所述第二镜组和所述第三镜组满足：
    Figure PCTCN2020079702-appb-100001
    其中，所述F为所述折射镜组的等效焦距，所述FB为所述第一镜组的等效焦距，所述FS为所述第二镜组的等效焦距，所述FT为所述第三镜组的等效焦距， 所述FM为所述反射镜组的等效焦距。
  9. 根据权利要求8所述的激光投影设备，其特征在于，所述第一镜组包括前9片透镜，所述第二镜组包括第10透镜，所述第三镜组包括后3片透镜。
  10. 根据权利要求8所述的激光投影设备，其特征在于，所述第一镜组可沿所述光轴方向前后移动。
  11. 根据权利要求8所述的激光投影设备，其特征在于，所述第二镜组可沿所述光轴方向前后移动。
  12. 根据权利要求8所述的激光投影设备，其特征在于，所述第三镜组为固定镜组，所述反射镜组可相对于所述第三镜组沿着所述光轴方向前后移动。
  13. 根据权利要求8所述的投影镜激光投影设备头，其特征在于，L2变化范围满足|△L2|≤1mm。
  14. 根据权利要求2所述的激光投影设备，其特征在于，前9片透镜均为玻璃镜片。
  15. 根据权利要求1或2所述的激光投影设备，其特征在于，所述第二片非球面透镜为塑胶镜片。
  16. 根据权利要求1所述的激光投影设备，其特征在于，所述投影镜头的后焦BFL满足：18mm≤BFL≤33mm，在所述光阀和所述投影镜头的折射镜组之间还设置有全反射棱镜和振镜，所述光阀出射的光经由所述全反射棱镜射出，所述振镜将所述全反射棱镜出射的光束偏移后入射所述投影镜头的折射镜组。
  17. 根据权利要求1所述的激光投影设备，其特征在于，所述投影镜头的投射比小于0.25，焦距在1.8至2.3之间。
  18. 根据权利要求8所述的激光投影设备，其特征在于，所述反射镜组包括一片自由曲面反射镜或凹面非球面反射镜。
PCT/CN2020/079702 2019-03-20 2020-03-17 激光投影设备 WO2020187204A1 (zh)

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CN203786377U (zh) * 2013-04-12 2014-08-20 富士胶片株式会社 投影镜头和投影显示设备
CN204241753U (zh) * 2013-06-12 2015-04-01 富士胶片株式会社 投射用变焦透镜及投射型显示装置
CN205608279U (zh) * 2015-04-01 2016-09-28 富士胶片株式会社 投射用变焦透镜以及投射型显示装置
CN108027498A (zh) * 2016-03-30 2018-05-11 松下知识产权经营株式会社 投射光学系统以及图像投射装置

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CN203786377U (zh) * 2013-04-12 2014-08-20 富士胶片株式会社 投影镜头和投影显示设备
CN204241753U (zh) * 2013-06-12 2015-04-01 富士胶片株式会社 投射用变焦透镜及投射型显示装置
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