An ultra-wide field-of-view virtual imaging display optical system

Abstract

The present invention discloses an ultra-large field of view virtual imaging display optical system, which is characterized by comprising an eyepiece front lens group with a virtual image magnification function and an objective lens rear lens group with a reduction function, an intermediate lens group is arranged between the eyepiece front lens group and the objective lens rear lens group, the focal length f1 of the eyepiece front lens group satisfies the following: 30mm≤f1≤44mm, the focal length f3 of the objective lens rear lens group satisfies the following: 50mm≤f3≤80mm, the focal length f2 of the intermediate lens group satisfies the following: 100mm≤f3≤250mm, and the total focal length f satisfies the following: 90mm≤f≤84mm. The optical system has the advantage of realizing an optical system design for virtual imaging display with ultra-high resolution, large image height, and low distortion by combining reasonable optical power and reasonable parameter matching.

Description

TECHNICAL FIELD

[0001] The present application relates to a virtual imaging display optical system, in particular to a super large field of view virtual imaging display optical system capable of being applied to education and medical treatment. BACKGROUND

[0002] In recent years, virtual imaging display systems have developed rapidly, especially with the advancement of various types of head-mounted display technologies, virtual display imaging system technology has gradually improved. Various types of head-mounted display devices guide the video images emitted by the miniature image display to the pupil position of the human eye through the optical system, and realize virtual and enlarged images in the near vision range of the user, providing visual information for the user. Initially, such technology was mainly applied to scientific research and military fields. With the popularization of electronic technology and the maturity of manufacturing industry, head-mounted virtual imaging display gradually enters people's life and is applied to industrial, medical, educational, consumer and other fields. Eyepiece optical imaging system is the core of virtual imaging display, which realizes the formation of virtual enlarged image in front of the human eye.

[0003] The eyepiece system of various types of head-mounted display is mainly for smaller displays, which are small in size and large in field of view angle (generally 120°, enhancing the experience). However, for some special use scenarios, such as some education and medical fields, it is required to realize 4K ultra-high definition resolution and meet the needs of switching between real and virtual scenes at any time. However, the existing eyepiece system of head-mounted display cannot meet the needs. Mainly affected by two aspects:

[0004] 1. Affected by the resolution of existing electronic technology display screen, the existing small display screen (generally less than 1 inch) cannot meet the requirements of ultra-high definition resolution, and the size of the existing 4K large display screen is relatively large (generally about 5 inches).

[0005] 2. In special use scenarios, the user's eyes have a non-fixed relative movement with the eyepiece imaging system, at which time it is required that the image is still clear to avoid causing the user's dizziness. This requires a large entrance pupil size, while the existing eyepiece system of head-mounted display is generally about 2-6mm.

[0006] In the technical solution of Chinese patent application with publication number CN113341558A, the display screen (image height) is about 16-19mm (about one inch), and the entrance pupil size is only 4-6mm, which cannot meet the above two special requirements. In patent CN104765151A, the entrance pupil diameter of the system is expanded to 8mm, but it cannot meet the requirement of large screen size. SUMMARY

[0007] The technical problem to be solved by the present application is to provide an ultra-large field virtual imaging display optical system with a large entrance pupil diameter, a large field angle and small distortion, which can meet the market demand for super-high-definition lens 4K clarity (large display screen).

[0008] The technical solution adopted by the present application to solve the above technical problem is: an ultra-large field virtual imaging display optical system, comprising an eyepiece front lens group ELG with virtual image magnification function and an objective lens rear lens group OLG with reduction function, an intermediate lens group MLG is arranged between the eyepiece front lens group ELG and the objective lens rear lens group OLG, the focal length f1 of the eyepiece front group satisfies 30mm≤f1≤44mm, the focal length f3 of the objective lens rear lens group satisfies 50mm≤f3≤80mm, the focal length f2 of the intermediate lens group satisfies 100mm≤f3≤250mm, and the total focal length f satisfies -90mm≤f≤-84mm.

[0009] Preferably, the eyepiece front lens group ELG is composed of four spherical lenses, the intermediate lens group MLG is composed of three spherical lenses, and the objective lens rear lens group OLG is composed of a group of large field light collecting spherical lenses.

[0010] Preferably, the eyepiece front lens group ELG is composed of a first lens group and a second lens group, the first lens group is composed of a first lens L1 with positive refractive power, a concave surface close to the entrance pupil side, and a convex surface on the other side, and the second lens group is composed of a double-convex second lens L2, a double-concave third lens L3 and a double-convex fourth lens L4, the second lens L2 and the fourth lens L4 have high dispersion, and the third lens L3 has low dispersion.

[0011] Preferably, the second lens L2, the third lens L3 and the fourth lens L4 are mutually cemented, or the second lens L2 is in a non-cemented manner, and the third lens L3 and the fourth lens L4 are mutually cemented.

[0012] Preferably, the intermediate lens group MLG is composed of a fifth lens L5, a sixth lens L6 and a seventh lens L7 in a cemented or non-cemented manner, the seventh lens L7 has positive or negative refractive power, and the side close to the image surface of the seventh lens L7 is a convex surface.

[0013] Preferably, the objective lens rear lens group OLG is composed of a positive refractive power eighth lens L8, a positive refractive power ninth lens L9, a negative refractive power tenth lens L10, and a first cemented lens GL1 composed of a double-cemented eleventh lens L11 and a twelfth lens L12, the tenth lens L10 has negative refractive power and a concave surface close to the image side, the first cemented lens GL1 has positive or negative refractive power, a convex surface close to the image side, and a concave surface close to the object side.

[0014] Preferably, the first lens L1 has positive focal power, is concave on the object side, and has a meniscus structure with a convex image side; the second lens L2 has positive focal power; the third lens L3 has negative focal power; the fourth lens L4 has positive focal power; the fifth lens L5 has positive or negative focal power; the sixth lens L6 has positive or negative focal power; the seventh lens L7 is a meniscus lens; the eighth lens L8 is a double convex lens; the ninth lens L9 is convex on the object side; the tenth lens L10 is concave on the image side; the eleventh lens L11 is a double convex lens with negative focal power; and the twelfth lens L12 is a double convex lens with positive focal power.

[0015] Preferably, the near-axis working F# of the entire system satisfies 9≤F#≤10, the total optical length TTL satisfies 350mm≤TTL≤460mm, and the image size IMG of the system satisfies 40mm≤IMG≤50mm. The virtual image magnification ɑ of the system satisfies 3.1<ɑ<3.5.

[0016] Preferably, the chromatic dispersion coefficient of the first lens L1 is Vd1, the chromatic dispersion coefficient of the second lens L2 is Vd2, the chromatic dispersion coefficient of the third lens L3 is Vd3, the chromatic dispersion coefficient of the fourth lens L4 is Vd4, the chromatic dispersion coefficient of the fifth lens L5 is Vd5, the chromatic dispersion coefficient of the sixth lens L6 is Vd6, the chromatic dispersion coefficient of the seventh lens L7 is Vd7, the chromatic dispersion coefficient of the eighth lens L8 is Vd8, the chromatic dispersion coefficient of the ninth lens L9 is Vd9, the chromatic dispersion coefficient of the tenth lens L10 is Vd10, the chromatic dispersion coefficient of the eleventh lens L11 is Vd11, and the chromatic dispersion coefficient of the twelfth lens L12 is Vd12, and the chromatic dispersion coefficients of the lenses satisfy Vd2, Vd4, Vd8, Vd9, Vd12>40, Vd1, Vd3, Vd10, Vd11<30, and Vd5, Vd6, Vd7 are matched with different chromatic dispersion coefficients according to different structure schemes.

[0017] Compared with the prior art, the application has the advantages that the focal powers are matched reasonably, and through reasonable parameter matching, an optical system design of virtual imaging display with super-high resolution, large image height, and low distortion is realized. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 is an optical structure diagram of embodiment 1 of the application;

[0019] Figure 2 is a transfer function curve diagram of embodiment 1 of the application;

[0020] Figure 3 is a field curvature distortion diagram of embodiment 1 of the application.

[0021] Figure 4 is a spot diagram of Example 1 of the present invention;

[0022] Figure 5 is an optical structure diagram of embodiment 2 of the present invention;

[0023] Figure 6 is a transfer function curve diagram of Example 2 of the present invention;

[0024] Figure 7 is a field curvature distortion diagram of Example 2 of the present invention;

[0025] Figure 8 is a spot diagram of Example 2 of the present invention;

[0026] Figure 9 is an optical structure diagram of Example 3 of the present invention;

[0027] Figure 10 is a transfer function curve diagram of Example 3 of the present invention;

[0028] Figure 11 is a field curvature distortion diagram of Example 3 of the present invention;

[0029] Figure 12 This is a point diagram of Example 3 of the present invention. DETAILED DESCRIPTION

[0030] The following describes the embodiments of the present invention in detail with reference to the accompanying drawings, which are for reference and illustration only and do not limit the scope of patent protection of the present invention.

[0031] Example 1:

[0032] In this implementation, to facilitate design modeling, we used the virtual image formed at the clear visual distance as the object plane position Sobj, the entrance pupil position as the system's field stop position IPD, and the display screen position as the system's image plane position Simg. In the optical design system, light travels from the virtual image at the clear visual distance to the right, reaching the system's image plane (display screen).

[0033] In this embodiment 1: Figure 1 As shown, from the object plane to the image plane are the eyepiece front lens group ELG with positive optical power, the middle lens group MLG with positive optical power and the objective lens rear lens group OLG with positive optical power.

[0034] The eyepiece front lens group ELG includes a first lens L1 with positive optical power, a second lens L2 with positive optical power, a third lens L3 with negative optical power and a fourth lens L4 with positive optical power. The first lens L1 is a meniscus lens with a concave object side and a convex image side. The second lens L2 is a biconvex lens, the third lens L3 is a biconcave lens, and the fourth lens L4 is a biconvex lens. The third lens L3 and the fourth lens L4 are cemented together.

[0035] The middle lens group MLG is composed of a fifth lens L5 with positive optical focal power, a sixth lens L6 with positive optical focal power, and a seventh lens L7 with negative optical focal power. The fifth lens L5 is a meniscus lens with a convex surface on the object side and a concave surface on the image side. The sixth lens L6 is a double convex lens. The seventh lens L7 is a meniscus lens with a concave surface on the object side and a convex surface on the image side.

[0036] The objective rear lens group OLG consists of an eighth lens L8 with positive focal power, a ninth lens L9 with positive focal power, a tenth lens L10 with negative focal power, an eleventh lens L11 with negative focal power, and a twelfth lens L12 with positive focal power. The eighth lens L8 and the twelfth lens L12 are both biconvex lenses, the ninth lens L9 is a positive lens with a convex object side surface and a concave image side surface, the tenth lens L10 is a negative lens with a convex object side surface and a concave image side surface, the eleventh lens L11 is a biconcave lens, and the eleventh lens L11 and the twelfth lens L12 are cemented together to form a first cemented lens GL1.

[0037] In this embodiment 1, the physical optical parameters of the entire lens are expressed as follows:

[0038]

[0039] The embodiment 1 of the present invention adopts a twelve-element structure to achieve a focal length of about -84mm, a maximum field of view of 85 degrees, and an image plane frame of about It can meet the requirements of 4K ultra-high-definition virtual system display with a pixel size of approximately 30um.

[0040] from Figures 2-4 It can be seen that the embodiment 1 can achieve MTF>25%@16lp / mm, distortion<4%, and achieve image width within 85° field of view. about.

[0041] Example 2:

[0042] In this embodiment 2, as Figure 5 As shown, from the object plane to the image plane are the eyepiece front lens group ELG with positive optical power, the middle lens group MLG with positive optical power and the objective lens rear lens group OLG with positive optical power.

[0043] The eyepiece front lens group ELG includes a first lens L1 with positive optical power, a second lens L2 with positive optical power, a third lens L3 with negative optical power, and a fourth lens L4 with positive optical power. The first lens L1 is a meniscus lens with a concave object side and a convex image side. The second lens L2 is a biconvex lens, the third lens L3 is a biconcave lens, and the fourth lens L4 is a biconvex lens. The second lens L2, the third lens L3 and the fourth lens L4 are cemented together.

[0044] The middle lens group MLG consists of a fifth lens element L5 with negative optical power, a sixth lens element L6 with positive optical power, and a seventh lens element L7 with negative optical power. Fifth lens L5 is a meniscus lens with a concave object-side surface and a convex image-side surface. Sixth lens L6 is a meniscus lens with a convex object-side surface and a concave image-side surface. Seventh lens L7 is a meniscus lens with a concave object-side surface and a convex image-side surface.

[0045] The objective rear lens group OLG consists of an eighth lens L8 with positive focal power, a ninth lens L9 with positive focal power, a tenth lens L10 with negative focal power, an eleventh lens L11 with negative focal power, and a twelfth lens L12 with positive focal power. The eighth lens L8 and the twelfth lens L12 are both biconvex lenses, the ninth lens L9 is a positive lens with a convex object-side surface and a concave image-side surface, the tenth lens L10 and the eleventh lens L11 are biconcave lenses, and the eleventh lens L11 and the twelfth lens L12 are cemented together to form a first cemented lens GL1.

[0046] In this embodiment 2, the physical optical parameters of the entire lens are expressed as follows:

[0047]

[0048]

[0049] The second embodiment of the present invention adopts a twelve-element structure to achieve a focal length of about -91mm, a maximum field of view of 85 degrees, and an image plane of about It can meet the requirements of 4K ultra-high-definition virtual system display with a pixel size of approximately 30um.

[0050] from Figures 6-8 It can be seen that the second embodiment can achieve MTF>15%@16lp / mm, distortion<4%, and image width within 85° field of view. about.

[0051] Example 3:

[0052] In this embodiment 3: Figure 9 As shown, from the object plane to the image plane are the eyepiece lens front group ELG with positive optical power, the middle lens group MLG with positive optical power and the objective lens rear group OLG with positive optical power.

[0053] Wherein the eyepiece front lens group ELG comprises a first lens L1 with positive refractive power, a second lens L2 with positive refractive power, a third lens L3 with negative refractive power, and a fourth lens L4 with positive refractive power, the first lens L1 is a meniscus lens with a concave object side and a convex image side, the second lens L2 is a double convex lens, the third lens L3 is a double concave lens, and the fourth lens L4 is a double convex lens, and the third lens L3 and the fourth lens L4 are cemented.

[0054] The intermediate lens group MLG is composed of a fifth lens L5 with positive refractive power, a sixth lens L6 with negative refractive power, and a seventh lens L7 with positive refractive power, the fifth lens L5 is a meniscus lens with a convex object side and a concave image side, the sixth lens L6 is a meniscus lens with a concave object side and a convex image side, the seventh lens L7 is a meniscus lens with a concave object side and a convex image side, and the sixth lens L6 and the seventh lens L7 are cemented.

[0055] The objective lens rear lens group OLG is composed of an eighth lens L8 with positive refractive power, a ninth lens L9 with positive refractive power, a tenth lens L10 with negative refractive power, an eleventh lens L11 with negative refractive power, and a twelfth lens L12 with positive refractive power, the eighth lens L8 and the twelfth lens L12 are both double convex lenses, the ninth lens L9 is a positive lens with a convex object side and a concave image side, the tenth lens L10 is a plano-concave lens with a concave image side, and the eleventh lens L11 is a double concave lens, and the eleventh lens L11 and the twelfth lens L12 are cemented to form a first cemented lens GL1.

[0056] In the embodiment 3, the physical and optical parameters of the entire lens are as follows:

[0057]

[0058]

[0059] The embodiment 3 of the present application adopts a twelve-piece structure, realizes a focal length of about -91 mm, and a maximum field of view angle of about 85 degrees, and an image plane format of about which can meet the 4K ultra-high-definition virtual system display with a pixel size of about 30 um.

[0060] From Figures 10-12 It can be seen that the embodiment 3 can achieve MTF>30% @ 16 lp / mm, distortion<3.2%, and realize an image format of about left and right within a field of view of 85 degrees.

[0061] The main technical parameters of the above embodiments are shown in the following table:

[0062]

[0063]

[0064] The above merely illustrates the individual embodiments of the present application, and cannot limit the protection scope of the present application, thus, any equivalent changes made according to the patent application scope of the present application still belong to the scope covered by the present application.

Claims

1. An ultra-large field of view virtual imaging display optical system, characterized by: The invention comprises an eyepiece front lens group ELG with a virtual image magnification function and an objective lens rear lens group OLG with a reduction function, an intermediate lens group MLG is provided between the eyepiece front lens group ELG and the objective lens rear lens group OLG, the focal length f1 of the eyepiece front lens group ELG satisfies: 30mm≤f1≤44mm, the focal length f3 of the objective lens rear lens group satisfies: 50mm≤f3≤80mm, the focal length f2 of the intermediate lens group satisfies: 100mm≤f3≤250mm, and the total focal length f satisfies: -90mm≤f≤-84mm, the eyepiece front lens group ELG is composed of a first lens group and a second lens group, the first lens group is composed of a first lens L1 with positive focal power, a concave surface close to the entrance pupil side and a convex surface on the other side, the second lens group is composed of a biconvex second lens L2, a biconcave third lens L3 and The optical system is composed of a biconvex fourth lens L4, the second lens L2 and the fourth lens L4 have high dispersion, the third lens L3 has low dispersion, the intermediate lens group MLG is composed of a fifth lens L5, a sixth lens L6 and a seventh lens L7 in a cemented or non-cemented manner, the optical power of the seventh lens L7 is positive or negative, and the side of the seventh lens L7 close to the image plane is convex, the objective rear lens group OLG is composed of an eighth lens L8 with positive focal power, a ninth lens L9 with positive focal power, a tenth lens L10 with negative focal power and a first cemented lens GL1 composed of an eleventh lens L11 and a twelfth lens L12 in a double cemented manner, the tenth lens L10 has negative focal power and is concave near the image side, the first cemented lens GL1 has positive or negative focal power, is convex near the image side, and is concave near the object side.

2. The ultra-large field of view virtual imaging display optical system according to claim 1, characterized in that: The eyepiece front lens group ELG is composed of four spherical lenses, the middle lens group MLG is composed of three spherical lenses, and the objective rear lens group OLG is composed of a group of large-viewing-field light-collecting spherical lenses.

3. The ultra-large field of view virtual imaging display optical system according to claim 1, characterized in that: The second lens L2, the third lens L3 and the fourth lens L4 are cemented together, or the second lens L2 is not cemented, and the third lens L3 and the fourth lens L4 are cemented together.

4. The ultra-large field of view virtual imaging display optical system according to claim 1, wherein: The first lens L1 has positive optical power and is a meniscus structure with a concave object-side surface and a convex image-side surface; the second lens L2 has positive optical power, the third lens L3 has negative optical power, the fourth lens L4 has positive optical power, the fifth lens L5 is a meniscus lens with positive or negative optical power, the sixth lens L6 has positive or negative optical power, the seventh lens L7 is a meniscus lens, the eighth lens L8 is a biconvex lens, the ninth lens L9 has a convex object-side surface, the tenth lens L10 has a concave image-side surface, the eleventh lens L11 is a biconvex lens with negative optical power, and the twelfth lens L12 is a biconvex lens with positive optical power.

5. The ultra-large field of view virtual imaging display optical system according to claim 1, characterized in that: The paraxial working F# of the entire system satisfies: 9≤F#≤10, the total optical length TTL satisfies: 350mm≤TTL≤460mm, the image plane size IMG of the system is: φ120mm≤IMG≤φ140mm, and the virtual image magnification ɑ of the system clear vision distance is: 3.1<ɑ<3.

5.

6. The ultra-large field of view virtual imaging display optical system according to claim 1, wherein: The Abbe coefficient of the first lens L1 is Vd1, the Abbe coefficient of the second lens L2 is Vd2, the Abbe coefficient of the third lens L3 is Vd3, the Abbe coefficient of the fourth lens L4 is Vd4, and the Abbe coefficient of the fifth lens L5 is Vd5. The dispersion coefficient of the sixth lens L6 is Vd6, the dispersion coefficient of the seventh lens L7 is Vd7, the dispersion coefficient of the eighth lens L8 is Vd8, the dispersion coefficient of the ninth lens L9 is Vd9, the dispersion coefficient of the tenth lens L10 is Vd10, the dispersion coefficient of the eleventh lens L11 is Vd11, and the dispersion coefficient of the twelfth lens L12 is Vd12. The dispersion coefficients of the lenses satisfy the following conditions: Vd2, Vd4, Vd8, Vd9, and Vd12 are greater than 40, and Vd1, Vd3, Vd10, and Vd11 are less than 30. Different dispersion coefficients of Vd5, Vd6, and Vd7 are matched according to different structural schemes.

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