A dual-lens time-sharing and light-sharing optical path and optical device

Abstract

The invention relates to a dual-lens time-sharing and light-splitting optical path, comprising a chip, a prism, a transfer lens, a first lens, a beam splitter reflector, a steering reflector, a second lens and a time-sharing switching device; the prism is used to separate the illumination optical path and the imaging optical 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 first lens is used to re-image the real image plane; the beam splitter reflector is used to reflect the real image plane to form a beam splitting real image plane symmetrical about the reflection plane, and the beam splitting real image plane enters the second lens after passing through the steering reflector; the time-sharing switching device is used to move the beam splitter reflector to switch the imaging on the first lens and the second lens; through this time-sharing alternating display, the overlap of two scenes is realized at the screen, an AR scene or a 3D scene is created, the final projection brightness can be improved, a single chip is used to reduce the cost of optical and electronic components, 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 field of AR technology, and more specifically to a dual-lens time-sharing and light-sharing 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 such as: CN109471262A, the LCD display chip is directly used as the light source, 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 the use of 3 modulation chips for modulation respectively, plus a complex modulation prism, which has a high cost, large volume, and complex mass production process.

[0005] This requires a dual-lens beam splitting solution 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 time-sharing and light-sharing optical path and an optical device 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 time-sharing and light-splitting optical path is constructed, which includes a chip, a prism, a transfer lens, a first lens, a beam splitter reflector, a steering reflector, a second lens and a time-sharing switching device; the prism is used to separate the illumination optical path and the imaging optical 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 first lens is used to re-image the real image plane; the beam splitter reflector is used to reflect the real image plane to form a beam splitting real image plane symmetrical about the reflection plane, and the beam splitting real image plane enters the second lens after passing through the steering reflector; the time-sharing switching device is used to move the beam splitter reflector to switch the imaging on the first lens and the second lens.

[0009] The dual-lens time-sharing and light-splitting optical path described in the present invention, wherein the image transfer 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 corrected divergent light beam; the third negative power lens group is used as a field lens to correct the field curvature again.

[0010] In the dual-lens time-sharing and light-splitting optical path described in the present invention, 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.

[0011] The dual-lens time-sharing and light-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 time-sharing and light-splitting optical path of the present invention, wherein the second negative optical focal length lens group comprises 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 time-sharing and light-splitting optical path of 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 time-sharing and light-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 time-sharing and light-splitting optical path described in the present invention, 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.

[0016] The dual-lens time-sharing and light-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 time-sharing and light-splitting optical path, wherein the dual-lens time-sharing and 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 time-sharing switching device is used near the real image position; when the image needs to pass through the first lens, the time-sharing switching device is used to move the beam splitter reflector away, leaving the air, and the image is projected along the original path; when it needs to pass through the second lens, the time-sharing switching device moves the beam splitter reflector back, and the image is reflected into another lens and also projected on the screen; through this time-sharing alternating display, the overlap of the two scenes is achieved on the screen to create an AR scene or a 3D scene, which can improve the final projection brightness, use a single chip to reduce the cost of optical and electronic components, eliminate the polarization modulation optical path, and has a small size and 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 1This is a schematic diagram of the dual-lens time-sharing and light-sharing optical path structure of a preferred embodiment of the present invention;

[0021] Figure 2 It is a switching schematic diagram of a dual-lens time-sharing light-splitting optical path lens time-sharing switching device of a preferred embodiment of the present invention;

[0022] Figure 3 It is a schematic diagram of the structure of a dual-lens time-sharing and light-splitting optical path image transfer lens of a preferred embodiment of the present invention;

[0023] Figure 4 This is a schematic diagram of the imaging principle of a dual-lens time-sharing and light-splitting optical path transfer lens of a preferred embodiment of the present invention;

[0024] Figure 5 It is the lens surface data of the dual-lens time-sharing and light-splitting optical path image transfer lens of the preferred embodiment of the present invention;

[0025] Figure 6 The dual-lens time-sharing and light-sharing optical path corresponding to the preferred embodiment of the present invention Figure 5 Schematic diagram of lens numbers. DETAILED DESCRIPTION

[0026] 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.

[0027] The dual-lens time-sharing and light-sharing optical path of the preferred embodiment of the present invention is as follows: Figure 1 See also Figure 2-6 , including a chip 1, a prism 2, a relay lens 3, a first lens 4, a beam splitter reflector 5, a steering reflector 6, a second lens 7 and a time-sharing switching device; 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 relay lens 3 is an imaging lens, which is used to convert the physical chip display area into a real image plane 8 of a light path in the air; the first lens 4 is used to re-image the real image plane; the beam splitter reflector 5 is used to reflect the real image plane to form a beam splitting real image plane 9 symmetrical about the reflection plane, and the beam splitting real image plane 9 enters the second lens 7 after passing through the steering reflector 6; the time-sharing switching device is used to move the beam splitter reflector 5 to switch the imaging on the first lens 4 and the second lens 7;

[0028] After the light comes out of the prism 2, it passes through the image transfer lens 3, which is an imaging lens. It converts the display area of ​​the physical chip 1 into an optical real image plane 8 in the air. A reflector is used to realize the turning of the light path. A time-sharing switching device is used near the real image position. When the image needs to pass through the first lens, the time-sharing switching device is used to remove the beam splitter reflector 5, leaving the air, and the image is projected along the original path. When it needs to pass through the second lens, the time-sharing switching device moves the beam splitter reflector 5 back, and the image is reflected into another lens and also projected on the screen. Through this time-sharing alternating display, the overlap of two scenes is realized at the screen to create an AR scene or a 3D scene, which can improve the final projection brightness, use a single chip to reduce the cost of optical and electronic components, cancel the polarization modulation light path, small size, and easy mass production;

[0029] More specifically, using DMD non-polarized components can more than double the brightness compared to LCOS in polarized mode; using DMD, LCOS, or LCD chips, through image transfer lenses and beam splitting mirrors, the chip display content is displayed in time-sharing mode, replacing multiple display chips and reducing the use of chips and related components; DLP mode does not require complex and bloated modulation circuits and optical paths, the volume can be made smaller, and has more advantages in reliability and production;

[0030] The time-sharing switching device may be an IR-CUT or an existing device similar to the IR-CUT. The general principle of the IR-CUT is as follows: Figure 2 As shown, the IR-CUT outer frame 10 provides support and position limiting for the beam splitter reflector 5, and the beam splitter reflector moves left and right in a timing synchronized with the chip under the control of a motor or other electromagnetic device;

[0031] 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 without interfering in space.

[0032] Preferably, the beam splitter reflector can be switched according to the timing; the positions and inclinations of the beam splitter reflector and the steering reflector can be adjusted according to actual needs; for example, if it is desired that the beam splitting real image plane can be formed into an inclined image plane after passing through the second lens, the beam splitter reflector and the steering reflector can be rotated by a certain angle. Inclined image planes are widely used in HUDs.

[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 3 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, an AR device, a 3D projection 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 time-sharing and light-sharing optical path, characterized in that: The invention comprises a chip, a prism, a transfer lens, a first lens, a beam splitter reflector, a steering reflector, a second lens and a time-sharing switching device; 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 first lens is used to re-image the real image plane; the beam splitter reflector is used to reflect the real image plane to form a beam splitting real image plane symmetrical about the reflection plane, and the beam splitting real image plane enters the second lens after passing through the steering reflector; the time-sharing switching device is used to move the beam splitter reflector to switch the imaging on the first lens and the second lens; The image transfer 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 time-sharing and light-sharing 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 time-sharing and light-sharing 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 time-sharing and light-sharing 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 time-sharing and light-sharing 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 time-sharing and light-sharing 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 time-sharing and light-sharing 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 time-sharing and light-sharing 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, characterized in that: The optical device is provided with the dual-lens time-sharing and light-sharing optical path.

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