A dual-lens split-screen light splitting optical path and optical device

Abstract

The invention relates to a dual-lens split-screen light-splitting optical path, comprising a chip, a prism, a transfer lens, a main lens, a split-screen reflector, a steering reflector and a secondary lens; a transfer lens is added at the light outlet of the prism to image the effective display area of ​​the chip in the air on the other side of the transfer lens, a reflector is used near the real image position to reflect a part of the real image into the second lens light path, thereby playing a split-screen role, and the remaining light passes through the first imaging lens along the original light path. The chip only needs to display the respective content in the corresponding area to realize the overlap of two scenes on the screen, which is beneficial to improving the final projection brightness and reducing the cost of optical and electronic components. At the same time, the polarization modulation optical path is cancelled, the volume is small, and it is easy to mass produce.

Description

Technical Field

[0001] The present invention relates to the technical field of dual-lens split-screen light splitting, and more specifically, to a dual-lens split-screen light splitting optical path and optical equipment. Background Art

[0002] In displays similar to AR HUD and 3D projection, two different lenses are generally required to project different scene contents respectively, which are finally overlapped to produce a virtual reality effect.

[0003] The current solution in AR HUD is to use two display chips, one is DMD or LCOS, and the other is LCD. The two chips share part of the optical path to project scenes at different object distances. Similar patents include: CN109471262A. The LCD display chip is directly used as a light source, and the divergence angle is large. Most of the light cannot be collected by the imaging system, resulting in a huge loss of brightness. At the same time, the use of two chips also increases the complexity of the circuit, resulting in a decrease in reliability, and the cost is relatively expensive.

[0004] In the field of 3D display, polarization is commonly used. Through timing control, light of different polarization states enters two lenses respectively, and finally the light overlaps at the screen to form a 3D effect. Due to the use of polarizers and liquid crystal modulators, its brightness will be lost by at least half. Similar patents such as: CN206193432U require three modulation chips to be modulated separately, plus a complex modulation prism, which is costly, large in size, and complex in mass production process.

[0005] A dual-lens beam splitting solution is needed that can effectively improve brightness, reduce costs, reduce size, and be easy to mass produce. Summary of the invention

[0006] The technical problem to be solved by the present invention is to provide a dual-lens split-screen light splitting optical path and an optical device containing the dual-lens split-screen light splitting optical path in view of the above-mentioned defects of the prior art.

[0007] The technical solution adopted by the present invention to solve its technical problem is:

[0008] A dual-lens split-screen light path is constructed, which includes a chip, a prism, a transfer lens, a main lens, a split-screen reflector, a steering reflector and a sub-lens; the prism is used to separate the illumination light path and the imaging light path in the chip output light beam; the transfer lens is an imaging lens, which is used to convert the entity chip display area into a real image plane of a light path in the air; the main lens is used to receive part of the real image plane for re-imaging; the split-screen reflector is used to separate part of the real image plane and enter the sub-lens after passing through the steering reflector.

[0009] The dual-lens split-screen beam splitting optical path described in the present invention, wherein the image transfer lens includes a first negative optical focal length lens group, a first positive optical focal length lens group, a second negative optical focal length lens group, a second positive optical focal length lens group and a third negative optical focal length lens group which are sequentially arranged along the optical path direction; the first negative optical focal length lens group is used to diverge the light beam so as to increase the light beam aperture; the first positive optical focal length lens group is used to converge the light beam, and the converged light beam has the smallest aperture in the second negative optical focal length lens group after being transmitted over a certain distance; the second negative optical focal length lens group is used to correct the chromatic aberration of the light beam, and the second positive optical focal length lens group is used to converge the corrected divergent light beam; the third negative optical focal length lens group is used as a field lens to correct the field curvature again.

[0010] The dual-lens split-screen beam splitting optical path described in the present invention, wherein the first negative optical focal length lens group is a double concave negative lens, the optical focal length is controlled between -0.03 and -0.02, and the refractive index is between 1.5 and 1.7.

[0011] The dual-lens split-screen beam-splitting optical path described in the present invention, wherein the first positive optical focal length lens group includes two first plano-convex lenses, and the convex sides of the two first plano-convex lenses are arranged opposite to each other; the optical focal length of the two first plano-convex lenses is between 0.02-0.03, and the refractive index is between 1.8-1.9.

[0012] The dual-lens split-screen beam splitting optical path described in the present invention, wherein the second negative optical focal length lens group includes a triplet lens consisting of two positive lenses and a negative lens between the two positive lenses; the overall optical focal length of the triplet lens is between -0.02 and -0.01.

[0013] The dual-lens split-screen beam splitting optical path described in the present invention, wherein the refractive index of the negative lens is between 1.8 and 1.9, and the refractive index of the negative lens is greater than that of the two positive lenses; and the relative dispersion coefficient of the negative lens is between 0.01 and 0.02.

[0014] The dual-lens split-screen beam-splitting optical path described in the present invention, wherein the second positive optical focal length lens group includes a second plano-convex lens, a third plano-convex lens and a meniscus lens arranged in sequence; the second plano-convex lens is arranged opposite to the convex side of the third plano-convex lens, and the convex of the meniscus lens is arranged toward the third plano-convex lens; the optical focal length range of the second plano-convex lens is 0.01-0.02, the optical focal length range of the third plano-convex lens is 0.025-0.03, and the optical focal length range of the meniscus lens is 0.02-0.028; the refractive index range of the third plano-convex lens and the meniscus lens is both in the range of 1.8-1.85.

[0015] In the dual-lens split-screen beam splitting optical path described in the present invention, the third negative optical power lens group includes a plano-concave negative lens, the plano-concave negative lens has a refractive index of 1.6-1.7 and an optical power of -0.08 to -0.06.

[0016] The dual-lens split-screen beam splitting optical path described in the present invention, wherein a flat glass assembly is provided at the front end of the image transfer lens, and the flat glass assembly includes an optical mechanical prism equivalent flat glass and an adjustable flat glass; the adjustable flat glass can adjust the corresponding material, thickness and front and rear air gap according to different prism materials and thicknesses.

[0017] An optical device, according to the above-mentioned dual-lens split-screen light splitting optical path, wherein the dual-lens split-screen light splitting optical path is arranged on the optical device.

[0018] The beneficial effects of the present invention are as follows: an image transfer lens is added at the light outlet of the prism to image the effective display area of ​​the chip in the air on the other side of the transfer lens, a reflector is used near the real image position to reflect part of the real image into the light path of the second lens, thereby playing a screen splitting role, and the remaining light passes through the first imaging lens along the original light path. The chips only need to display their respective contents in the corresponding areas to achieve the overlap of the two scenes on the screen, which is beneficial to improving the final projection brightness and reducing the cost of optical and electronic components. At the same time, the polarization modulation light path is eliminated, the volume is small, and it is easy to mass produce. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the present invention will be further described below in conjunction with the accompanying drawings and embodiments. The drawings described below are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative work:

[0020] Figure 1 This is a schematic diagram of the dual-lens split-screen light splitting optical path structure of a preferred embodiment of the present invention;

[0021] Figure 2 It is a schematic diagram of the structure of a dual-lens split-screen beam splitting optical path image transfer lens of a preferred embodiment of the present invention;

[0022] Figure 3 This is a schematic diagram of the imaging principle of a dual-lens split-screen beam splitting optical path image transfer lens of a preferred embodiment of the present invention;

[0023] Figure 4 It is the lens surface data of the dual-lens split-screen light-splitting optical path image transfer lens of the preferred embodiment of the present invention;

[0024] Figure 5 The dual-lens split screen light splitting path corresponding to the preferred embodiment of the present invention Figure 4Schematic diagram of lens numbers. DETAILED DESCRIPTION

[0025] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the following will be described clearly and completely in combination with the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are partial embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work belong to the protection scope of the present invention.

[0026] The dual-lens split-screen light splitting path of the preferred embodiment of the present invention is as follows: Figure 1 See also Figure 2-5 , including a chip 1, a prism 2, a transfer lens 3, a main lens 4, a split screen reflector 5, a steering reflector 6 and a secondary lens 7; the prism 2 is used to separate the illumination light path and the imaging light path in the outgoing light beam of the chip 1; the transfer lens 3 is an imaging lens, which is used to convert the display area of ​​the physical chip 1 into a real image plane of a light path in the air; the main lens 4 is used to receive a part of the real image plane (the main real image plane 8) for re-imaging; the split screen reflector 5 is used to separate a part of the real image plane (the secondary real image plane 9) and enter the secondary lens 7 after passing through the steering reflector 6;

[0027] At the light outlet of the prism 2, a transfer lens 3 is added to image the effective display area of ​​the chip 1 in the air on the other side of the transfer lens. A reflector is used near the real image position to reflect part of the real image into the optical path of the second lens, which plays a role of splitting the screen. The remaining light passes through the first imaging lens along the original optical path. The chips only need to display their own content in the corresponding area to achieve the overlap of the two scenes on the screen, which is beneficial to improve the final projection brightness and reduce the cost of optical and electronic components. At the same time, the polarization modulation optical path is eliminated, the volume is small, and it is easy to mass produce.

[0028] Preferably, the chip 1 may be a display chip such as DMD or LCOS. The prism 2 may be TIR / RTIR or PBS, and its main function is to separate the illumination light path and the imaging light path so that they do not interfere with each other in space.

[0029] After the light comes out of the prism, it passes through the image relay lens 3, which is an imaging lens that converts the physical display area of ​​the chip 1 into an optical real image plane in the air, making it convenient to use a split-screen reflector to achieve physical segmentation.

[0030] The main real image plane 8 and the secondary real image plane 9 are both part of the real image plane of the image transfer lens; the main real image plane 8 is re-imaged by the main lens 4 and projected onto the screen.

[0031] The split screen reflector 5 separates a secondary real image plane 9 from the entire real image plane. After passing through the steering reflector 6, the secondary real image plane 9 enters the secondary lens 7 and is also projected on the screen, and together with the main real image plane, creates an AR scene or a 3D scene. If the outgoing light of the steering reflector 6 is extended in the reverse direction, a virtual image 10 of the secondary real image plane can be obtained on the right side of the steering reflector;

[0032] Preferably, the position, tilt and size of the split-screen reflector can be adjusted according to actual needs; for example, if the size of the secondary imaging surface is desired to be smaller, the split-screen reflector can be moved downward; if the secondary imaging surface is desired to be an inclined image surface after passing through the secondary lens, the split-screen reflector or the steering reflector can be rotated by a certain angle; the inclined image surface is widely used in HUD;

[0033] Preferably, the magnification of the image-shifting lens can be customized or made into a zoom, so that the size of the real image plane can be controlled manually; when the volume is required to be relatively small, the real image plane is made smaller, and if the proportion of the transition area between the main real image plane and the secondary real image plane is expected to be relatively small, then the real image plane can be made larger; the flexibility of the image-shifting lens is very high;

[0034] Figure 2 In the figure, reference numeral 11 is a chip protection glass, and reference numeral 12 is an imaging surface;

[0035] Preferably, the image transfer lens 3 comprises a first negative power lens group 30, a first positive power lens group 31, a second negative power lens group 32, a second positive power lens group 33 and a third negative power lens group 34 which are sequentially arranged along the optical path direction; the first negative power lens group 30 is used to diverge the light beam so as to increase the light beam aperture; the first positive power lens group 31 is used to converge the light beam, and the converged light beam has the smallest aperture in the second negative power lens group 32 after being transmitted over a certain distance; the second negative power lens group 32 is used to correct the chromatic aberration of the light beam, and the second positive power lens group 33 is used to converge the corrected divergent light beam; the third negative power lens group 34 is used as a field lens to correct the field curvature again;

[0036] The image-relay lens scheme of the present invention can be used not only for other display chips including LCOS, but also for optical machine bodies with different prisms, and has low cost and good mass production performance. Of course, other existing image-relay lens schemes can also be used to achieve the invention purpose of the present application, and such simple replacement methods all fall within the protection scope of the present application.

[0037] Specifically, for a system with a large field of view and conjugated object and image, in order to obtain better image quality, various aberrations need to be corrected, among which chromatic aberration and field curvature are important aberrations; the correction of field curvature requires separation of positive and negative optical powers, and a high light height at the positive optical power and a low light height at the negative optical power; therefore, a "waist and belly" structure will appear in the light beam in the lens, with negative optical power at the "waist" where the light beam is tightened and positive optical power at the "belly" where the light beam is expanded; this light height distribution on the positive and negative optical powers effectively corrects the field curvature; the correction of chromatic aberration requires a cemented lens, and the overall optical power of the cemented lens is weak; therefore, the cemented lens is very suitable for being placed near the aperture of the system;

[0038] According to the above theory, the distribution of optical power of the object-image conjugate system with a large field of view is a symmetrical distribution of "negative-positive-negative-positive-negative". Of course, since the object and image are not completely symmetrical (there is a prism on the object side but not on the image side), the specific lens contours or materials are not completely symmetrical. The negative optical power at both ends of the system actually acts as a field lens, effectively correcting the field curvature and introducing fewer other aberrations. The curvature, thickness, material and air spacing of all lenses are used to correct other aberrations.

[0039] Preferably, the first negative optical power lens group 30 is a double concave negative lens, the optical power is controlled between -0.03 and -0.02, and the refractive index is between 1.5 and 1.7; it can quickly increase the beam aperture within a short distance.

[0040] Preferably, the first positive optical focal length lens group 31 includes two first plano-convex lenses 310, and the convex sides of the two first plano-convex lenses 310 are arranged opposite to each other; the optical focal length of the two first plano-convex lenses 310 is between 0.02-0.03, and the refractive index is between 1.8-1.9; the strong positive optical focal length is shared by the two first plano-convex lenses 310 to reduce high-order aberrations; in order to avoid high-order aberrations caused by excessive light angles, the optical focal length is controlled between 0.02 and 0.03, and the refractive index is between 1.8 and 1.9. The use of high refractive index materials is beneficial to improving the light deflection ability of the lens.

[0041] Preferably, the second negative power lens group 32 includes a triplet lens consisting of two positive lenses 320 and a negative lens 321 between the two positive lenses; the overall focal length of the triplet lens is between -0.02 and -0.01; preferably, the refractive index of the negative lens 321 is between 1.8 and 1.9, and the refractive index of the negative lens 321 is greater than that of the two positive lenses; the relative dispersion coefficient of the negative lens 321 is between 0.01 and 0.02;

[0042] Here, chromatic aberration correction can also be achieved by using a combination of double-cemented lenses and single lenses.

[0043] Preferably, the second positive power lens group 33 includes a second plano-convex lens 330, a third plano-convex lens 331 and a meniscus lens 332 which are arranged in sequence; the second plano-convex lens 330 is arranged opposite to the convex side of the third plano-convex lens 331, and the convex of the meniscus lens 332 is arranged toward the third plano-convex lens 331; the focal power range of the second plano-convex lens is 0.01-0.02, the focal power range of the third plano-convex lens is 0.025-0.03, and the focal power range of the meniscus lens is 0.02-0.028; the refractive index range of the third plano-convex lens and the meniscus lens is both 1.8-1.85; in order to share the strong positive power, three positive lenses are used here to share the burden, so as to reduce high-order aberrations;

[0044] The second positive power lens group 33 has one more positive lens than the first positive power lens group 31 , because it is closer to the imaging surface and needs a stronger light deflection capability;

[0045] The third plano-convex lens 331 and the meniscus lens 332 are lenses that bear the main optical power, and the second plano-convex lens 330 is made of a low refractive index and low dispersion material to reduce chromatic aberration;

[0046] Preferably, the third negative optical focal length lens group 34 includes a plano-concave negative lens with a refractive index of 1.6-1.7 and an optical focal length of -0.08 to -0.06. It acts as a field lens to reduce field curvature and ensure image telecentricity, and its outgoing light beam is projected onto the imaging surface to form a clear light spot.

[0047] Preferably, a flat glass assembly 35 is provided at the front end of the image transfer lens 3, and the flat glass assembly 35 includes an optical mechanical prism equivalent flat glass 350 and an adjustable flat glass 351; the adjustable flat glass 12 can adjust the appropriate material, thickness and front and rear air gap according to different prism materials and thicknesses.

[0048] An optical device, according to the above-mentioned dual-lens split-screen light splitting optical path, wherein the optical device is provided with a dual-lens split-screen light splitting optical path; the optical device can be a photo taking device, a video recording device, etc.

[0049] It should be understood that those skilled in the art can make improvements or changes based on the above description, and all these improvements and changes should fall within the scope of protection of the appended claims of the present invention.

Claims

1. A dual-lens split-screen light splitting path, characterized in that: It includes a chip, a prism, a transfer lens, a main lens, a split screen reflector, a steering reflector and a sub-lens; the prism is used to separate the illumination light path and the imaging light path in the chip output light beam; the transfer lens is an imaging lens, which is used to convert the physical chip display area into a real image plane of a light path in the air; the main lens is used to receive part of the real image plane for re-imaging; the split screen reflector is used to separate part of the real image plane and enter the sub-lens after passing through the steering reflector; The image relay lens comprises a first negative power lens group, a first positive power lens group, a second negative power lens group, a second positive power lens group and a third negative power lens group which are sequentially arranged along the optical path direction; the first negative power lens group is used to diverge the light beam so as to increase the light beam aperture; the first positive power lens group is used to converge the light beam, and the converged light beam has the smallest aperture in the second negative power lens group after being transmitted over a certain distance; the second negative power lens group is used to correct the chromatic aberration of the light beam, and the second positive power lens group is used to converge the divergent light beam after correction; the third negative power lens group is used as a field lens to correct the field curvature again.

2. The dual-lens split-screen light splitting optical path according to claim 1, characterized in that: The first negative optical power lens group is a double concave negative lens, the optical power is controlled between -0.03 and -0.02, and the refractive index is between 1.5 and 1.

7.

3. The dual-lens split-screen light splitting optical path according to claim 2, characterized in that: The first positive power lens group includes two first plano-convex lenses, and the convex sides of the two first plano-convex lenses are arranged opposite to each other; the optical power of the two first plano-convex lenses is between 0.02-0.03, and the refractive index is between 1.8-1.

9.

4. The dual-lens split-screen beam splitting optical path according to claim 1, characterized in that: The second negative optical power lens group includes a triplet lens consisting of two positive lenses and a negative lens between the two positive lenses; the overall optical power of the triplet lens is between -0.02 and -0.

01.

5. The dual-lens split-screen light splitting optical path according to claim 4, characterized in that: The refractive index of the negative lens is between 1.8 and 1.9, and the refractive index of the negative lens is greater than that of the two positive lenses; the relative dispersion coefficient of the negative lens is between 0.01 and 0.

02.

6. The dual-lens split-screen light splitting optical path according to claim 1, characterized in that: The second positive optical focal length lens group includes a second plano-convex lens, a third plano-convex lens and a meniscus lens which are arranged in sequence; the second plano-convex lens is arranged opposite to the convex side of the third plano-convex lens, and the convex portion of the meniscus lens is arranged toward the third plano-convex lens; the optical focal length range of the second plano-convex lens is 0.01-0.02, the optical focal length range of the third plano-convex lens is 0.025-0.03, and the optical focal length range of the meniscus lens is 0.02-0.028; the refractive index ranges of the third plano-convex lens and the meniscus lens are both in the range of 1.8-1.

85.

7. The dual-lens split-screen beam splitting optical path according to claim 1, characterized in that: The third negative optical power lens group includes a plano-concave negative lens, the refractive index of the plano-concave negative lens is 1.6-1.7, and the optical power is -0.08 to -0.

06.

8. The dual-lens split-screen light splitting optical path according to claim 1, characterized in that: A flat glass assembly is disposed at the front end of the image transfer lens, and the flat glass assembly includes an optical mechanical prism equivalent flat glass and an adjustable flat glass; the adjustable flat glass can adjust the material, thickness and front and rear air gaps according to different prism materials and thicknesses.

9. An optical device, according to any one of claims 1 to 8, wherein: The dual-lens split-screen light splitting optical path is arranged on the optical device.

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