CN112526762A - Double-lens time-sharing light splitting optical path and optical equipment - Google Patents

Abstract

The invention relates to a double-lens time-sharing light-splitting light path which comprises a chip, a prism, an image rotating lens, a first lens, a light-splitting reflector, a steering reflector, a second lens and a time-sharing switching device, wherein the image rotating lens is arranged on the chip; the prism is used for separating an illumination light path and an imaging light path in an emergent light beam of the chip; the image conversion lens is an imaging lens and is used for converting a chip display area of an entity into a real image surface of a light path in the air; the first lens is used for imaging the real image surface again; the beam splitting reflector is used for reflecting the real image surface to form a beam splitting real image surface which is symmetrical about the reflecting surface, and the beam splitting real image surface enters the second lens after passing through the steering reflector; the time-sharing switching device is used for moving the time-sharing reflector to switch imaging on the first lens and the second lens; through the time-sharing alternate display, the two scenes are overlapped at the screen, an AR scene or a 3D scene is created, the final projection brightness can be improved, the cost of optics and electronic components is reduced by using a single chip, a polarization modulation light path is cancelled, the size is small, and the mass production is easy.

Description

Double-lens time-sharing light splitting optical path and optical equipment

Technical Field

The invention relates to the technical field of AR (augmented reality), in particular to a double-lens time-sharing light splitting optical path and optical equipment.

Background

In AR HUD and 3D-like projection displays, two different lenses are typically required, projecting different scene content separately, and finally overlapping to create a virtual reality effect.

At present, the existing scheme in the AR HUD is to use two display chips, one is a DMD or LCOS, and the other is an LCD, and the two chips share part of the optical path to project scenes with different object distances; similar specializations are as follows: CN109471262A, the LCD display chip is directly used as a light source, the divergence angle is very large, most of light rays can not be collected to an imaging system, and the great loss of brightness is caused; meanwhile, the use of two chips also increases the complexity of the circuit, which leads to a decrease in reliability and is relatively expensive.

In the field of 3D display, a polarization mode is generally adopted, light rays with different polarization states respectively enter two lenses through time sequence control, and finally the light rays are overlapped at a screen to form a 3D effect; because of using polarizing and liquid crystal modulator, its luminance will lose more than half at least; similar specializations are as follows: CN206193432U patent requires 3 modulation chips for modulation respectively, and adds a complex modulation prism, which is high in cost, large in volume, and complex in mass production process.

There is a need for a dual-lens light splitting scheme that can effectively improve brightness, reduce cost, reduce volume, and facilitate mass production.

Disclosure of Invention

The present invention provides a dual-lens time-sharing optical splitting path and an optical device, aiming at the above-mentioned defects in the prior art.

The technical scheme adopted by the invention for solving the technical problems is as follows:

the double-lens time-sharing light-splitting optical path is constructed and comprises a chip, a prism, an image rotating lens, a first lens, a light-splitting reflector, a steering reflector, a second lens and a time-sharing switching device; the prism is used for separating an illumination light path and an imaging light path in an emergent light beam of the chip; the image conversion lens is an imaging lens and is used for converting a chip display area of an entity into a real image surface of a light path in the air; the first lens is used for imaging the real image surface again; the beam splitting reflector is used for reflecting the real image surface to form a beam splitting real image surface which is symmetrical about the reflecting surface, and the beam splitting real image surface enters the second lens after passing through the steering reflector; the time-sharing switching device is used for moving the light-sharing reflector to switch imaging on the first lens and the second lens.

The invention relates to a double-lens time-sharing light splitting optical path, wherein an image rotating lens comprises a first negative focal power lens group, a first positive focal power lens group, a second negative focal power lens group, a second positive focal power lens group and a third negative focal power lens group which are sequentially arranged along the direction of the optical path; the first negative power lens group is used for diverging the light beam so as to increase the aperture of the light beam; the first positive focal power lens group is used for converging light beams, and the converged light beams have the smallest caliber in the second negative focal power lens group after being transmitted at a certain distance; the second negative focal power lens group is used for correcting chromatic aberration of the light beam, and the second positive focal power lens group is used for converging the corrected divergent light beam; the third negative power lens group is used as a field lens to correct the curvature of field again.

The double-lens time-sharing light splitting optical path is characterized in that the first negative focal power lens group is a double-concave negative lens, the focal power is controlled to be-0.03-0.02, and the refractive index is controlled to be 1.5-1.7.

The invention relates to a double-lens time-sharing light splitting optical path, wherein a first positive focal power lens group comprises two first plano-convex lenses, and convex sides of the two first plano-convex lenses are oppositely arranged; the focal power of each of the two first plano-convex lenses is between 0.02 and 0.03, and the refractive index of each first plano-convex lens is between 1.8 and 1.9.

The double-lens time-sharing light splitting optical path comprises a first negative power lens group, a second negative power lens group and a third negative power lens group, wherein the first negative power lens group comprises a third cemented lens consisting of two positive lenses and a negative lens between the two positive lenses; the total focal power of the tri-cemented lens is between-0.02 and-0.01.

The invention relates to a double-lens time-sharing light splitting optical path, wherein the refractive index of a negative lens is between 1.8 and 1.9, and the refractive index of the negative lens is larger than that of two positive lenses; the relative dispersion coefficient of the negative lens is between 0.01 and 0.02.

The double-lens time-sharing light splitting optical path comprises a first positive focal power lens group, a second positive focal power lens group, a third positive focal power lens group and a third positive focal power lens group, wherein the first positive focal power lens group comprises a first plano-convex lens, a third plano-convex lens and a meniscus lens which are sequentially arranged; the second plano-convex lens is opposite to the convex side of the third plano-convex lens, and the convex side of the meniscus lens is arranged towards the third plano-convex lens; said second plano-convex lens power range is 0.01-0.02, said third plano-convex lens power range is 0.025-0.03, said meniscus lens power range is 0.02-0.028; the refractive index of the third plano-convex lens and the refractive index of the meniscus lens are both in the range of 1.8-1.85.

The double-lens time-sharing light splitting optical path comprises a third negative focal power lens group, wherein the third negative focal power lens group comprises a plano-concave negative lens, the refractive index of the plano-concave negative lens is 1.6-1.7, and the focal power of the plano-concave negative lens is-0.08-0.06.

The invention relates to a double-lens time-sharing light splitting light path, wherein a plate glass component is arranged at the front end of an image rotating lens, and comprises optical machine prism equivalent plate glass and adjusting plate glass; the adjusting plate glass can adjust the adaptive material and thickness and the front and back air space according to different prism materials and thicknesses.

An optical device is provided with the double-lens time-sharing light-splitting optical path.

The invention has the beneficial effects that: the method comprises the steps of adding an image transfer lens at a light-emitting position of a prism, imaging an effective display area of a chip in air on the other side of the image transfer lens, using a time-sharing switching device near a real image position, moving a light-dividing reflecting mirror away by using the time-sharing switching device when an image needs to pass through a first lens, and leaving air, projecting the image along an original path, moving the light-dividing reflecting mirror back by using the time-sharing switching device when the image needs to pass through a second lens, reflecting the image into another lens, and projecting the image on a screen.

Drawings

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 with reference to the accompanying drawings and embodiments, wherein the drawings in the following description are only part of the embodiments of the present invention, and for those skilled in the art, other drawings can be obtained without inventive efforts according to the accompanying drawings:

FIG. 1 is a schematic diagram of a dual-lens time-sharing optical path structure according to a preferred embodiment of the present invention;

FIG. 2 is a schematic switching diagram of the dual-lens time-sharing and light-splitting optical path lens time-sharing switching apparatus according to the preferred embodiment of the present invention;

FIG. 3 is a schematic diagram of a dual-lens time-sharing and light-splitting optical path image-rotating lens according to a preferred embodiment of the present invention;

FIG. 4 is a schematic diagram of an imaging lens with a dual lens for time-sharing and light-splitting optical path transformation according to a preferred embodiment of the present invention;

FIG. 5 is a schematic diagram of a lens surface data of a dual-lens time-sharing optical splitting optical path relay lens according to a preferred embodiment of the present invention;

fig. 6 is a schematic diagram of a dual-lens time-sharing beam splitting optical path according to a preferred embodiment of the invention corresponding to the reference numerals of the lens in fig. 5.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the following will clearly and completely describe the technical solutions in the embodiments of the present invention, and it is obvious that the described embodiments are some embodiments of the present invention, but not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments of the present invention without inventive step, are within the scope of the present invention.

The double-lens time-sharing light-splitting optical path of the preferred embodiment of the present invention is shown in fig. 1, and also shown in fig. 2-6, and comprises a chip 1, a prism 2, an image-rotating lens 3, a first lens 4, a light-splitting reflector 5, a turning reflector 6, a second lens 7 and a time-sharing switching device; the prism 2 is used for separating an illumination light path and an imaging light path in an emergent light beam of the chip 1; the image transfer lens 3 is an imaging lens and is used for converting a chip display area of an entity into a real image surface 8 of a light path in the air; the first lens 4 is used for imaging the real image surface again; the beam splitting reflector 5 is used for reflecting the real image surface to form a beam splitting real image surface 9 which is symmetrical about the reflecting surface, and the beam splitting real image surface 9 enters the second lens 7 after passing through the steering reflector 6; the time-sharing switching device is used for moving the time-sharing reflector 5 to switch imaging on the first lens 4 and the second lens 7;

after light comes out of the prism 2, the light passes through the image transfer lens 3, the image transfer lens 3 is an imaging lens, a display area of an entity chip 1 is converted into an optical real image surface 8 in the air, the reflector is used for realizing the turning of an optical path, a time-sharing switching device is used near the real image position, when an image needs to pass through a first lens, the time-sharing switching device is used for removing the light-dividing reflector 5 and leaving air, the image is projected along the original path, when the image needs to pass through a second lens, the time-sharing switching device moves the light-dividing reflector 5 back, the image enters another lens after being reflected and is also projected on a screen, through the time-sharing alternate display, the superposition of two scenes is realized at the screen, an AR scene or a 3D scene is created, the final projection brightness can be improved, the cost of optical and electronic components is reduced by using a single chip, and the polarization modulation optical path is cancelled, the volume is small, and the mass production is easy;

more specifically, the brightness is improved by more than one time compared with LCOS in a polarization mode by using DMD non-polarization components; the display content of the chip is displayed in a time-sharing way by using chips such as a DMD (digital micromirror device), an LCOS (liquid Crystal on silicon) or an LCD (liquid Crystal display), and the like through the image conversion lens and the light splitting reflector, so that a plurality of display chips are replaced, and the use of the chips and related components is reduced; in the DLP mode, a complex and bulky modulation circuit and a light path are not needed, the size can be small, and the DLP mode has more advantages in reliability and production;

the time-sharing switching device can adopt an IR-CUT or an existing device similar to the IR-CUT, the IR-CUT is roughly as shown in figure 2 in principle, an IR-CUT outer frame 10 provides support and limit for a light-dividing reflector 5, and the light-dividing reflector moves left and right under a motor or other electromagnetic devices according to a time sequence synchronous with a chip;

preferably, the chip 1 may be a display chip such as a DMD or an LCOS; the prism 2, which may be a TIR/RTIR or PBS, serves primarily to separate the illumination and imaging optical paths from spatial interference.

Preferably, the beam splitting mirror is switchable in position according to timing; the positions of the beam splitting reflector and the steering reflector can be adjusted according to actual requirements; for example, if it is desired that the splitting real image plane can be an inclined image plane through the second lens, the splitting mirror and the turning mirror can be rotated by a certain angle. Tilted image planes have common application in HUDs.

Preferably, the magnification of the image transfer lens can be customized or made into zooming, so that the size of the real image surface can be manually controlled; when the required volume is smaller, the real image surface is smaller, and the proportion of a transition area between the main real image surface and the auxiliary real image surface is expected to be smaller, so that the real image surface can be larger; the flexibility of the image transfer lens is very high;

in fig. 3, reference numeral 11 denotes a chip protective glass, and 12 denotes an imaging surface;

preferably, the image rotating lens 3 includes 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 for diverging the light beam so as to increase the aperture of the light beam; the first positive power lens group 31 is used for converging the light beam, and the converged light beam has the smallest caliber in the second negative power lens group 32 after being transmitted for a certain distance; the second negative power lens group 32 is used for correcting chromatic aberration of the light beam, and the second positive power lens group 33 is used for converging the corrected divergent light beam; the third negative power lens group 34 is used as a field lens to correct curvature of field again;

by applying the image conversion lens scheme, not only can other display chips including LCOS be used universally, but also the optical machine main bodies of different prisms can be switched, and the image conversion lens has low cost and good mass production; certainly, other existing image conversion lens schemes can be adopted to achieve the purpose of the invention, and the simple alternative mode belongs to the protection scope of the application;

specifically, for a system of object image conjugation with a large field of view, in order to obtain better image quality, various aberrations need to be corrected, and chromatic aberration and curvature of field are important aberrations; correction of curvature of field requires positive and negative power separation and has high ray height in positive power and low ray height in negative power; therefore, the light beam in the lens has a waist-belly structure, the waist part where the light beam is tightened is negative focal power, and the belly part where the light beam is expanded is positive focal power; this light height distribution over positive and negative power strongly corrects curvature of field; the chromatic aberration correction needs a cemented lens, and the integral focal power of the cemented lens is weaker; therefore, the cemented lens is very suitable for being placed near the diaphragm of the system;

according to the theory, the distribution of the focal power of the object image conjugate system with a large visual field is symmetrical distribution of negative-positive-negative; of course, since the object image is not completely symmetrical (the object side has a prism and the image side does not), the specific lens profile or material may not be completely symmetrical; the negative focal powers at the two ends of the system actually play the role of a field lens, effectively corrects curvature of field and introduces less other aberrations; all the lens curvatures, thicknesses, materials, air gaps, etc. are used to correct other aberrations.

Preferably, the first negative power lens group 30 is a biconcave negative lens, the power is controlled between-0.03 and-0.02, and the refractive index is controlled between 1.5 and 1.7; the aperture of the light beam can be rapidly increased within a short distance.

Preferably, the first positive power lens group 31 includes two first plano-convex lenses 310, and convex sides of the two first plano-convex lenses 310 are arranged oppositely; the focal power of the two first plano-convex lenses 310 is between 0.02 and 0.03, and the refractive index is between 1.8 and 1.9; the strong positive focal power is shared by the two first plano-convex lenses 310 to reduce the high-order aberration; in order to avoid the high-level aberration caused by the overlarge light angle, the focal power is controlled to be 0.02-0.03, the refractive index is 1.8-1.9, and the high-refractive-index material is favorable for improving the light deflection capability of the lens.

Preferably, the second negative power lens group 32 includes a triple cemented lens composed of two positive lenses 320 and a negative lens 321 between the two positive lenses; the total focal power of the tri-cemented 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 Abbe number of the negative lens 321 is between 0.01-0.02;

the correction of chromatic aberration can also be achieved here by means of a combination of double cemented lenses and single lenses.

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 this order; the second plano-convex lens 330 is disposed opposite to the convex side of the third plano-convex lens 331, and the convex side of the meniscus lens 332 is disposed toward the third plano-convex lens 331; the focal power of the second plano-convex lens is 0.01-0.02, the focal power of the third plano-convex lens is 0.025-0.03, and the focal power of the meniscus lens is 0.02-0.028; the refractive index of the third plano-convex lens and the refractive index of the meniscus lens are both in the range of 1.8-1.85; in order to share strong positive power, three positive lenses are used here to share to reduce high order aberrations;

the second positive power lens group 33 has one more positive lens than the first positive power lens group 31 because the light deflection capability needs to be stronger closer to the image plane;

the third plano-convex lens 331 and the meniscus lens 332 are lenses bearing the main focal power, and the second plano-convex lens 330 is made of a low-refractive-index low-dispersion material to reduce chromatic aberration;

preferably, the third negative power lens group 34 comprises a plano-concave negative lens, the refractive index of the plano-concave negative lens is 1.6-1.7, and the power is-0.08 to-0.06; the field lens reduces field curvature and ensures image space telecentricity, and outgoing light beams of the field lens are projected to an imaging plane to form clear light spots.

Preferably, a flat glass assembly 35 is arranged at the front end of the relay lens 3, and the flat glass assembly 35 comprises an optical machine prism equivalent flat glass 350 and an adjusting flat glass 351; the adjusting plate glass 12 can adjust the material and thickness of the prism and the air space between the front and the back according to the material and the thickness of the prism.

An optical device is provided with the dual-lens split-screen light splitting optical path according to the dual-lens split-screen light splitting optical path; the optical device may be a photographing device, a video recording device, an AR device, a 3D projection device, or the like.

It will be understood that modifications and variations can be made by persons skilled in the art in light of the above teachings and all such modifications and variations are intended to be included within the scope of the invention as defined in the appended claims.

Claims (10)

1. A double-lens time-sharing light-splitting light path is characterized by comprising a chip, a prism, an image rotating lens, a first lens, a light-splitting reflector, a steering reflector, a second lens and a time-sharing switching device; the prism is used for separating an illumination light path and an imaging light path in an emergent light beam of the chip; the image conversion lens is an imaging lens and is used for converting a chip display area of an entity into a real image surface of a light path in the air; the first lens is used for imaging the real image surface again; the beam splitting reflector is used for reflecting the real image surface to form a beam splitting real image surface which is symmetrical about the reflecting surface, and the beam splitting real image surface enters the second lens after passing through the steering reflector; the time-sharing switching device is used for moving the light-sharing reflector to switch imaging on the first lens and the second lens.

2. The dual-lens time-sharing light-splitting optical path according to claim 1, wherein the 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 arranged in sequence along the optical path direction; the first negative power lens group is used for diverging the light beam so as to increase the aperture of the light beam; the first positive focal power lens group is used for converging light beams, and the converged light beams have the smallest caliber in the second negative focal power lens group after being transmitted at a certain distance; the second negative focal power lens group is used for correcting chromatic aberration of the light beam, and the second positive focal power lens group is used for converging the corrected divergent light beam; the third negative power lens group is used as a field lens to correct the curvature of field again.

3. The dual-lens time-sharing optical splitting path of claim 2, wherein the first negative power lens group is a double-concave negative lens, the power is controlled between-0.03 and-0.02, and the refractive index is controlled between 1.5 and 1.7.

4. The dual-lens time-sharing light-splitting optical path according to claim 3, wherein the first positive power lens group comprises two first plano-convex lenses, and convex sides of the two first plano-convex lenses are arranged oppositely; the focal power of each of the two first plano-convex lenses is between 0.02 and 0.03, and the refractive index of each first plano-convex lens is between 1.8 and 1.9.

5. The dual-lens time-sharing optical splitting optical path of claim 2, wherein the second negative power lens group comprises a triple cemented lens consisting of two positive lenses and a negative lens intermediate the two positive lenses; the total focal power of the tri-cemented lens is between-0.02 and-0.01.

6. The dual-lens time-sharing light-splitting optical path of claim 5, 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; the relative dispersion coefficient of the negative lens is between 0.01 and 0.02.

7. The dual-lens time-sharing light-splitting optical path according to claim 2, wherein the second positive power lens group comprises 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 opposite to the convex side of the third plano-convex lens, and the convex side of the meniscus lens is arranged towards the third plano-convex lens; said second plano-convex lens power range is 0.01-0.02, said third plano-convex lens power range is 0.025-0.03, said meniscus lens power range is 0.02-0.028; the refractive index of the third plano-convex lens and the refractive index of the meniscus lens are both in the range of 1.8-1.85.

8. The dual-lens time-sharing optical splitting optical path of claim 2, wherein the third negative power lens group comprises a plano-concave negative lens, the refractive index of the plano-concave negative lens is 1.6-1.7, and the optical power of the plano-concave negative lens is-0.08 to-0.06.

9. The dual-lens time-sharing light-splitting optical path according to claim 2, wherein a plate glass assembly is arranged at the front end of the relay lens, and the plate glass assembly comprises an optical machine prism equivalent plate glass and an adjusting plate glass; the adjusting plate glass can adjust the adaptive material and thickness and the front and back air space according to different prism materials and thicknesses.

10. An optical device, the dual-lens time-sharing light-splitting optical path according to any one of claims 1 to 9, wherein the dual-lens time-sharing light-splitting optical path is provided on the optical device.

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