CN113504654A - Near-to-eye display optical system - Google Patents
Near-to-eye display optical system Download PDFInfo
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- CN113504654A CN113504654A CN202110890570.2A CN202110890570A CN113504654A CN 113504654 A CN113504654 A CN 113504654A CN 202110890570 A CN202110890570 A CN 202110890570A CN 113504654 A CN113504654 A CN 113504654A
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
- G02B27/01—Head-up displays
- G02B27/017—Head mounted
- G02B27/0172—Head mounted characterised by optical features
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
- G02B27/0025—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00 for optical correction, e.g. distorsion, aberration
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Abstract
The embodiment of the invention discloses a near-eye display optical system, which comprises: the first lens, the second lens, the third lens and the fourth lens are sequentially arranged from an object plane to an image plane along the optical axis direction; the first lens is a positive focal power lens, the second lens is a negative focal power lens, the third lens is a positive focal power lens, and the fourth lens is a positive focal power lens. The near-to-eye display optical system provided by the embodiment of the invention can optimize the transmission light and reasonably control the volume of the optical system, so that the lens group has small volume, light weight and clear imaging.
Description
Technical Field
The embodiment of the invention relates to the technical field of near-eye display, in particular to a near-eye display optical system.
Background
With the rapid development of near-eye display technology, from early application to military, to current augmented reality, virtual reality and mixed reality, the near-eye display technology will be widely applied in more fields and gradually come into our lives.
The near-to-eye display of augmented reality enables a user to project a virtual image to the eyes of the user while observing the surrounding real environment, and the projected virtual image can be superimposed in the real world as perceived by the user. Therefore, the near-to-eye display of the augmented reality can be generally applied to multiple fields of military affairs, industry, entertainment, medical treatment and the like, and brings greater convenience to users.
In order to realize the near-eye display technology, the existing scheme mainly comprises a geometric array optical waveguide mode, a diffraction optical waveguide mode, a free-form surface mode and a prism mode, and because the near-eye display device needs to be worn on the head of a user, the light weight design and the clear display effect of the product are the key points of product design, and along with the smaller and smaller size of the near-eye display device, the difficulty of optical system design is increased.
In the prior art, a near-to-eye display optical system adopting the lens group generally needs to be provided with a plurality of lenses, the number of the lenses is large, not only can the processing cost be increased, but also the difficulty of a plurality of optical pieces and structural parts during assembly is large, the production working hours are increased, and the yield of the product quality can be reduced.
Disclosure of Invention
Embodiments of the present invention provide a near-eye display optical system to provide an optical system with low cost and simple assembly.
An embodiment of the present invention provides a near-eye display optical system, including: the first lens, the second lens, the third lens and the fourth lens are sequentially arranged from an object plane to an image plane along the optical axis direction;
the first lens is a positive focal power lens, the second lens is a negative focal power lens, the third lens is a positive focal power lens, and the fourth lens is a positive focal power lens.
Optionally, the second lens and the third lens are fixed by gluing.
Optionally, the first lens, the second lens, the third lens and the fourth lens are all spherical lenses.
Optionally, a lens in the near-eye display optical system includes opposite object-side and image-side surfaces, the object-side surface of the lens is close to the object plane, and the image-side surface of the lens is close to the image plane;
the first lens is a convex-concave lens, the object side surface of the first lens is a concave surface, and the image side surface of the first lens is a convex surface;
the second lens is a biconcave lens, and both the object side surface and the image side surface of the second lens are concave surfaces;
the third lens is a biconvex lens, and both the object side surface and the image side surface of the third lens are convex surfaces;
the fourth lens is a plano-convex lens, the object side surface of the fourth lens is a plane, and the image side surface of the fourth lens is a convex surface.
Optionally, the lens further comprises an image source, and the image source is positioned on the side of the first lens far away from the second lens.
Optionally, the image source includes any one of a liquid crystal display, a silicon-based liquid crystal display, an organic light emitting diode, a micro light emitting diode, and a digital micromirror device.
Optionally, the lens module further comprises a switching device, and the switching device is located on a side of the fourth lens, which is far away from the third lens.
Optionally, the switching device includes a waveguide sheet or a prism.
Optionally, the focal length of the optical system is f, wherein f is more than 10mm and less than 15 mm.
The near-to-eye display optical system provided by the embodiment of the invention comprises the first lens, the second lens, the third lens and the fourth lens which are sequentially arranged from an object plane to an image plane along the optical axis direction, the number of the lenses of the optical system is less, the volume of the optical system is small, and the processing cost and the assembly difficulty can be reduced. Furthermore, the first lens provides positive focal power, the second lens and the third lens respectively provide negative focal power and positive focal power, the fourth lens provides positive focal power, the focal power of the optical system is a combination of positive, negative, positive and positive modes, the size of the optical system can be reasonably controlled while the transmission light is optimized, and the lens group is small in size, light in weight and clear in imaging.
Drawings
To more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, a brief description will be given below of the drawings required for the embodiments or the technical solutions in the prior art, and it is obvious that the drawings in the following description, although being some specific embodiments of the present invention, can be extended and extended to other structures and drawings by those skilled in the art according to the basic concepts of the device structure, the driving method and the manufacturing method disclosed and suggested by the various embodiments of the present invention, without making sure that these should be within the scope of the claims of the present invention.
Fig. 1 is a schematic structural diagram of a near-eye display optical system according to an embodiment of the present invention;
FIG. 2 is a schematic view of curvature of field and distortion of a near-eye display optical system in a full-field full-waveband of a full field of view according to an embodiment of the present invention;
FIG. 3 is a schematic diagram of a full field of view transfer function MTF curve of a near-eye display optical system provided by an embodiment of the present invention at a resolution of 30 lp/mm;
fig. 4 is a full field of view diagram of a near-eye display optical system according to an embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention clearer, the technical solutions of the present invention will be clearly and completely described through embodiments with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the basic idea disclosed and suggested by the embodiments of the present invention, are within the scope of the present invention.
Fig. 1 is a schematic structural diagram of a near-eye display optical system according to an embodiment of the present invention, and as shown in fig. 1, the near-eye display optical system according to the embodiment of the present invention includes: a first lens 100, a second lens 200, a third lens 300, and a fourth lens 400 arranged in order from an object plane to an image plane in an optical axis direction; the first lens 100 is a positive power lens, the second lens 200 is a negative power lens, the third lens 300 is a positive power lens, and the fourth lens 400 is a positive power lens.
The focal power is equal to the difference between the convergence of the image-side beam and the convergence of the object-side beam, and characterizes the ability of the optical system to deflect light. The larger the absolute value of the focal power is, the stronger the bending ability to the light ray is, and the smaller the absolute value of the focal power is, the weaker the bending ability to the light ray is. When the focal power is positive, the refraction of the light is convergent; when the focal power is negative, the refraction of the light is divergent. The optical power can be suitable for representing a certain refractive surface of a lens (namely, a surface of the lens), can be suitable for representing a certain lens, and can also be suitable for representing a system (namely a lens group) formed by a plurality of lenses together.
Exemplarily, referring to fig. 1, the near-eye display optical system provided in this embodiment includes a first lens 100, a second lens 200, a third lens 300, and a fourth lens 400 arranged in sequence from an object plane to an image plane in a coaxial manner, and the optical system has a small number of lenses, a small volume, and can reduce the processing cost and the assembly difficulty. Specifically, the first lens 100 has positive focal power, can correct curvature of field of light in the optical system, and reduce the incident angle of the light, so that the imaging quality of the optical system can be improved, the field angle of the optical system can be increased, the volume of the lens group consisting of the first lens 100, the second lens 200, the third lens 300 and the fourth lens 400 can be reduced, and the volume and the quality of the whole structure can be further reduced; the second lens 200 and the third lens 300 respectively have negative focal power and positive focal power, the second lens 200 and the third lens 300 can correct spherical aberration and chromatic aberration of the optical system, the fourth lens 400 has positive focal power, light rays are corrected after passing through the second lens 200, the third lens 300 and the fourth lens 400, and the contributed spherical aberration does not affect the imaging quality of the system.
The near-to-eye display optical system provided by the embodiment of the invention comprises the first lens, the second lens, the third lens and the fourth lens which are sequentially arranged from an object plane to an image plane along the optical axis direction, the number of the lenses of the optical system is less, the volume of the optical system is small, and the processing cost and the assembly difficulty can be reduced. Furthermore, the first lens provides positive focal power, the second lens and the third lens respectively provide negative focal power and positive focal power, the fourth lens provides positive focal power, the focal power of the optical system is a combination of positive, negative, positive and positive modes, the size of the optical system can be reasonably controlled while the transmission light is optimized, and the lens group is small in size, light in weight and clear in imaging.
Referring to fig. 1, the second lens 200 is optionally fixed by gluing with the third lens 300.
In this embodiment, the image-side surface of the second lens element 200 and the object-side surface of the third lens element 300 are cemented and fixed to form a cemented structure, which can correct spherical aberration and chromatic aberration of the optical system. The second lens 200 and the third lens 300 are fixed by gluing, which not only facilitates the processing and assembly, but also ensures the coaxiality of the two glued lenses. In addition, the air space between the second lens 200 and the third lens 300 can be effectively reduced by adopting the gluing structure, so that the length of the optical system is shortened, and the miniaturization is further realized.
It should be noted that, the above is only explained by the example of the cemented fixation of the second lens 200 and the third lens 300, but not limited thereto, and in other embodiments, the second lens 200 and the third lens 300 may be non-cemented.
Referring to fig. 1, optionally, the first lens 100, the second lens 200, the third lens 300, and the fourth lens 400 are all spherical lenses.
In this embodiment, the first lens element 100, the second lens element 200, the third lens element 300, and the fourth lens element 400 of the optical system are all spherical lens elements, and compared with aspheric lens elements, the spherical lens elements have better image quality, lower processing difficulty, and easy detection.
It is understood that in other embodiments, a person skilled in the art may set the first lens 100, the second lens 200, the third lens 300, and the fourth lens 400 of the optical system to be aspheric lenses according to practical situations.
Referring to fig. 1, optionally, a lens in the near-eye display optical system includes opposite object and image sides, the object side of the lens is close to the object plane, and the image side of the lens is close to the image plane; the first lens element 100 is a convex-concave lens element, the object-side surface of the first lens element 100 is a concave surface, and the image-side surface of the first lens element 100 is a convex surface; the second lens element 200 is a biconcave lens element, and both the object-side surface and the image-side surface of the second lens element 200 are concave surfaces; the third lens element 300 is a biconvex lens element, and both the object-side surface and the image-side surface of the third lens element 300 are convex; the fourth lens element 400 is a plano-convex lens element, the object-side surface of the fourth lens element 400 is a flat surface, and the image-side surface of the fourth lens element 400 is a convex surface.
Exemplarily, referring to fig. 1, the first lens 100 is a convex-concave lens with positive refractive power, the convex surface of which is close to the image plane, and the concave surface of which is close to the object plane, and the first lens 100 is a meniscus lens, which can be used as a field lens of an optical system, and can effectively reduce the size of all lenses inside the optical system, make light compact, and reduce the volume of the optical system.
The second lens 200 is a biconcave lens with negative focal power, the third lens 300 is a biconvex lens with positive focal power, and the second lens 200 and the third lens 300 can correct light more compactly, effectively reduce the volume of an optical system, and control spherical aberration and chromatic aberration of the optical system in a range as small as possible, thereby being beneficial to improving image quality.
The fourth lens 400 is a plano-convex lens, the convex surface of which is close to the image plane, and the plane of which is close to the object plane, so as to provide positive focal power for the optical system, mainly contribute to positive spherical aberration, but not affect the imaging quality. The plano-convex lens is easy to process, can reduce the processing cost, is convenient for the assembly of the whole machine, is easy to ensure the assembly precision, and can also effectively reduce the volume of the optical system.
Referring to fig. 1, optionally, the near-eye display optical system further includes an image source 500, the image source 500 being located on a side of the first lens 100 away from the second lens 200.
The near-eye display optical system provided by the embodiment further includes an image source 500, and the first lens 100, the second lens 200, the third lens 300, and the fourth lens 400 are sequentially disposed on a propagation path of light emitted by the image source 500. The first lens 100 can be used for correcting the curvature of field of the optical system and reducing the incident angle of light; the second lens 200 and the third lens 300 provide optical power and spherical aberration for the optical system; the fourth lens 400 provides a positive optical power for the optical system. After the light emitted from the image source 500 is corrected by the first lens 100, the second lens 200, the third lens 300 and the fourth lens 400, the spherical aberration generated by the propagating light is within the control allowable range, and finally the light is emitted to the exit pupil position of the near-eye display optical system, and the light emitted from the exit pupil position is the corrected parallel light.
On the basis of the above embodiments, the image source 500 may optionally include any one of a liquid crystal display, a silicon-based liquid crystal display, an organic light emitting diode, a micro light emitting diode, and a digital micro mirror device.
In order to control the total volume of the near-eye Display optical system, the image source 500 may select a Display source having a volume as small as possible, and the Display source includes, but is not limited to, Display chips such as a Liquid Crystal Display (LCD), a Liquid Crystal On Silicon (LCOS), an Organic Light-Emitting Diode (OLED), a Micro Light-Emitting Diode (Micro-LED), and a Digital Micro-mirror device (DMD). In addition, the image source 500 preferably uses display chips with a size of 0.2 inch to 0.5 inch, such as 0.23 inch OLED display chips, 0.39 inch OLED display chips, and the like.
Referring to fig. 1, optionally, the near-eye display optical system further includes an adapter 600, where the adapter 600 is located on a side of the fourth lens 400 away from the third lens 300.
Light rays are emitted out through the exit pupil position of the optical system after being transmitted by the lens group, the switching device 600 can be arranged at the exit pupil position, the light rays enter the eyes of a user after being transmitted by the switching device 600, and a virtual image is formed in the retina of the human eyes to be received. In other embodiments, the exit pupil position may also be viewed by the eyes of the user, i.e. the light emitted from the optical system can be directly received by the eyes of the human eye to form an image.
Optionally, the adapter 600 includes a waveguide plate or a prism, and may be used for multiple applications such as geometric array optical wave plate or prism transmission, and has a wide application range.
Optionally, the focal length of the optical system is f, wherein f is more than 10mm and less than 15 mm.
The focal length f of the near-to-eye display optical system provided by the embodiment of the invention meets the following requirements: f is more than 10mm and less than 15mm, the focal length of the optical system is shorter, the volume and the weight of the optical system can be further reduced, and the cost is reduced.
Further, fig. 2 is a schematic view of curvature of field and distortion of a near-eye display optical system in a full-field full-waveband, as shown in fig. 2, in a left-side coordinate system, an abscissa represents a size of the curvature of field in millimeters, and an ordinate represents a field angle in degrees, as can be seen from the figure, the curvature of field of the near-eye display optical system provided in this embodiment is about 0.1mm, the curvature of field is small, a center of the field of view and an edge of the field of view can be seen at the same time, and an image quality is relatively clear. In the right coordinate system, the abscissa represents percentage, which reflects the distortion, and the ordinate represents the field angle, with the unit being degree, it can be seen from the figure that the distortion of the near-eye display optical system provided by the embodiment is about 0.9% and less than 1%, the imaging distortion is small, the distortion is well corrected, and the requirement of low distortion is met.
Fig. 3 is a schematic diagram of an MTF curve of a full-field transfer function of a near-eye display optical system provided by an embodiment of the present invention at a resolution of 30lp/mm, and as shown in fig. 3, the MTF curve at 30lp/mm has a transfer function of substantially 0.3 or more, which can meet a requirement of a visual resolution.
Fig. 4 is a full field of view spot diagram of a near-eye display optical system according to an embodiment of the present invention, which is one of the most common evaluation methods in modern optical design. The point diagram is that after many light rays emitted by a point light source pass through an optical system, intersection points of the light rays and an image surface are not concentrated on the same point any more due to aberration, and a diffusion pattern scattered in a certain range is formed. As shown in fig. 4, the root mean square radius values (RMS radius) of the visible rays (0.486 μm, 0.588 μm and 0.656 μm) with different wavelengths at each field position of the optical system are 8.778 μm, 7.327 μm, 5.834 μm, 11.171 μm, 26.748 μm, 6.552 μm, 4.392 μm, 3.126 μm, 3.954 μm and 26.987 μm, respectively, which shows the fact that each ray emitted from the image source is imaged on the image plane after passing through the optical system, i.e. the optical system has lower chromatic aberration and aberration in the full field of view, and can realize high-resolution imaging.
In summary, the near-to-eye display optical system provided by the embodiment of the invention has the advantages of less lenses, shorter optical system length, small volume, portability, and capability of reducing the processing cost and the assembly difficulty; the optical system has clear imaging, high resolution and small aberration, can be used for near-eye display, and has wide application when being coupled into the system by using an eyepiece, a geometric array optical waveguide and the like.
It is to be noted that the foregoing is only illustrative of the preferred embodiments of the present invention and the technical principles employed. It will be understood by those skilled in the art that the present invention is not limited to the particular embodiments described herein, but is capable of various obvious modifications, rearrangements, combinations and substitutions as will now become apparent to those skilled in the art without departing from the scope of the invention. Therefore, although the present invention has been described in greater detail by the above embodiments, the present invention is not limited to the above embodiments, and may include other equivalent embodiments without departing from the spirit of the present invention, and the scope of the present invention is determined by the scope of the appended claims.
Claims (9)
1. A near-eye display optical system, comprising: the first lens, the second lens, the third lens and the fourth lens are sequentially arranged from an object plane to an image plane along the optical axis direction;
the first lens is a positive focal power lens, the second lens is a negative focal power lens, the third lens is a positive focal power lens, and the fourth lens is a positive focal power lens.
2. The near-eye display optical system of claim 1, wherein the second lens is cemented to the third lens.
3. The near-eye display optical system of claim 1, wherein the first lens, the second lens, the third lens, and the fourth lens are all spherical lenses.
4. The near-eye display optical system of claim 3, wherein the lens in the near-eye display optical system comprises opposite object and image side surfaces, the object side surface of the lens being proximate to the object plane and the image side surface of the lens being proximate to the image plane;
the first lens is a convex-concave lens, the object side surface of the first lens is a concave surface, and the image side surface of the first lens is a convex surface;
the second lens is a biconcave lens, and both the object side surface and the image side surface of the second lens are concave surfaces;
the third lens is a biconvex lens, and both the object side surface and the image side surface of the third lens are convex surfaces;
the fourth lens is a plano-convex lens, the object side surface of the fourth lens is a plane, and the image side surface of the fourth lens is a convex surface.
5. The near-eye display optical system of claim 1, further comprising an image source located on a side of the first lens distal from the second lens.
6. The near-to-eye display optical system of claim 5 wherein the image source comprises any one of a liquid crystal display, a silicon-based liquid crystal display, an organic light emitting diode, a micro light emitting diode, and a digital micromirror device.
7. The near-eye display optical system of claim 1, further comprising an adapter device located on a side of the fourth lens away from the third lens.
8. The near-eye display optical system of claim 7, wherein the relay device comprises a waveguide sheet or a prism.
9. The near-to-eye display optical system of claim 1, wherein the optical system has a focal length f, wherein 10mm < f < 15 mm.
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| Application Number | Priority Date | Filing Date | Title |
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| CN202110890570.2A CN113504654A (en) | 2021-08-04 | 2021-08-04 | Near-to-eye display optical system |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202110890570.2A CN113504654A (en) | 2021-08-04 | 2021-08-04 | Near-to-eye display optical system |
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| CN113504654A true CN113504654A (en) | 2021-10-15 |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114942522A (en) * | 2022-06-28 | 2022-08-26 | 深圳珑璟光电科技有限公司 | Optical system and near-to-eye display equipment |
| CN115166943A (en) * | 2022-07-18 | 2022-10-11 | 歌尔光学科技有限公司 | Optical system and augmented reality equipment |
| CN115268085A (en) * | 2022-09-27 | 2022-11-01 | 江西联昊光电有限公司 | Eyepiece optical system and head-mounted display device |
-
2021
- 2021-08-04 CN CN202110890570.2A patent/CN113504654A/en active Pending
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114942522A (en) * | 2022-06-28 | 2022-08-26 | 深圳珑璟光电科技有限公司 | Optical system and near-to-eye display equipment |
| CN115166943A (en) * | 2022-07-18 | 2022-10-11 | 歌尔光学科技有限公司 | Optical system and augmented reality equipment |
| CN115166943B (en) * | 2022-07-18 | 2024-03-12 | 歌尔光学科技有限公司 | Optical system and augmented reality device |
| CN115268085A (en) * | 2022-09-27 | 2022-11-01 | 江西联昊光电有限公司 | Eyepiece optical system and head-mounted display device |
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