CN217156945U - Projection optical device and head-mounted augmented reality equipment - Google Patents
Projection optical device and head-mounted augmented reality equipment Download PDFInfo
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- CN217156945U CN217156945U CN202122355144.7U CN202122355144U CN217156945U CN 217156945 U CN217156945 U CN 217156945U CN 202122355144 U CN202122355144 U CN 202122355144U CN 217156945 U CN217156945 U CN 217156945U
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Abstract
The utility model provides a projection optical device and wear-type augmented reality equipment, projection optical device includes: the display unit, the fourth lens, the third lens, the second lens and the first lens are sequentially arranged along the light transmission direction; the first lens, the second lens and the fourth lens all have positive focal power, and the third lens has negative focal power; the first lens is convex along the light incident surface of the optical axis direction, and the light emergent surface of the first lens along the optical axis direction is concave. The light incident surface and the light emergent surface of the second lens along the optical axis direction are convex surfaces; the light incident surface and the light emitting surface of the third lens along the optical axis direction are both concave surfaces; the light incident surface and the light emergent surface of the fourth lens along the optical axis direction are convex surfaces. Compared with the prior art, the utility model discloses a projection optical device can reduce when guaranteeing great angle of vision under four lens composite action the lens number that projection optical device used for whole projection optical device is small, light in weight.
Description
Technical Field
The utility model relates to an optical imaging technology field especially relates to a projection optical device and a wear-type augmented reality equipment.
Background
The waveguide type augmented reality display device mainly comprises two optical components, wherein one optical component is a projection optical device for providing amplified display images and comprises a display unit and a lens component; the other is a waveguide device for transmitting the image beam.
The main function of the lens assembly is to enlarge the image source displayed by the display unit, form a virtual image at a certain distance, and image the image on the retina of the user through the waveguide device. The existing lens assembly has the defects of large number of lenses and large volume, and easily causes the heavy weight of the whole projection optical device, so that the waveguide type augmented reality display equipment is inconvenient to carry.
SUMMERY OF THE UTILITY MODEL
An object of the utility model is to provide a projection optical device to solve the shortcoming among the prior art and not enough. The projection optical device has the advantages of small volume and light weight.
The utility model discloses a projection optical device, it includes: the display unit, the fourth lens, the third lens, the second lens and the first lens are sequentially arranged along the light transmission direction; the first lens, the second lens and the fourth lens all have positive focal power, and the third lens has negative focal power;
the first lens is convex along the light incident surface of the optical axis direction, and the light emergent surface of the first lens along the optical axis direction is concave.
The light incident surface and the light emergent surface of the second lens along the optical axis direction are convex surfaces;
the light incident surface and the light emitting surface of the third lens along the optical axis direction are both concave surfaces;
the light incident surface and the light emergent surface of the fourth lens along the optical axis direction are convex surfaces.
Compared with the prior art, the utility model discloses a projection optical device can reduce when guaranteeing great angle of vision under four lens composite action the lens number that projection optical device used for whole projection optical device is small, light in weight.
The utility model also provides a wear-type augmented reality equipment, including wearing the part and as above projection optical device, projection optical device arranges in wear on the part. The beneficial effects of the head-mounted augmented reality device including the projection optical device are omitted for brevity.
Drawings
Fig. 1 is a schematic structural diagram of a projection optical apparatus according to an embodiment of the present invention;
fig. 2 is a schematic structural diagram of a projection optical device according to another embodiment of the present invention;
fig. 3 is a schematic structural diagram of a projection optical apparatus according to still another embodiment of the present invention;
FIG. 4 is a schematic view of the projection optical apparatus of the present invention when a mirror or a turning prism is disposed;
FIG. 5 is a schematic view of the projection optical apparatus of the present invention without a reflector or a turning prism;
FIG. 6 is a graph of field curvature and distortion corresponding to the projection optics of the present invention;
FIG. 7 is a diagram of lateral chromatic aberration corresponding to the projection optics of the present invention;
fig. 8 is a graph showing a modulation transfer function corresponding to the projection optical device of the present invention.
Detailed Description
Referring to fig. 1, the projection optical device of the present embodiment includes: the display unit 10, the fourth lens 60, the third lens 50, the second lens 40, and the first lens 30 are sequentially disposed along a light transmission direction. The projection optical device according to this embodiment is applied to a head-mounted augmented reality device, and light emitted from the first lens 30 may enter the waveguide device, and enter human eyes after being guided by the waveguide device.
Optionally, the display unit 10 may be a DMD or an LCOS display chip, or may also be a Mini/Micro-LED or a Micro-OLED. In this embodiment, the display unit 10 is a Mini/Micro-LED or a Micro-OLED.
The first lens 30, the second lens 40 and the fourth lens 60 all have positive focal power, and the third lens 50 has negative focal power. Optical power is used to denote the ability of an optical system to deviate light rays, where a lens with positive optical power denotes its ability to focus light rays, and a lens with negative optical power denotes its ability to diverge light rays.
The light incident surface 32 of the first lens 30 along the optical axis direction is a convex surface, and the light emitting surface 31 along the optical axis direction is a concave surface; the light incident surface 42 and the light emitting surface 41 of the second lens 40 along the optical axis direction are both convex surfaces; the light incident surface 52 and the light emitting surface 51 of the third lens 50 along the optical axis direction are both concave surfaces; the light incident surface 62 and the light emitting surface 61 of the fourth lens 60 along the optical axis direction are both convex surfaces.
The light emitted by the display unit 10 sequentially passes through the fourth lens 60, the third lens 50, the second lens 40 and the first lens 30 and then is emitted, and under the combined action of the four lenses in this embodiment, the number of lenses used by the projection optical device can be reduced while a larger field angle is ensured, so that the whole projection optical device is small in size and light in weight.
In a preferred embodiment, the light incident surface and the light emitting surface of the first lens 30, the second lens 40, the third lens 50 and the fourth lens 60 along the optical axis direction are all aspheric surfaces. I.e. a total of eight surfaces of the four lenses are aspheric surface type. The aspheric surface type lens has more degrees of freedom, can better reduce the aberration of the whole projection optical device, and improves the imaging quality. Meanwhile, the projection optical device is lighter, thinner and flatter, and is beneficial to realizing the miniaturization of the projection optical device. The aspheric surface type lens is used, so that the miniaturization of the projection optical device is met, and the requirement of high imaging quality is met.
As an alternative embodiment, the projection optics satisfy the following relationship:
5.0≤f1/f≤20.0；0.5≤f2/f≤1.5；-0.3≤f3/f≤-1.0；0.5≤f4/f≤1.0。
wherein f is a focal length of the projection optics, f1 is a focal length of the first lens 30, f2 is a focal length of the second lens 40, f3 is a focal length of the third lens 50, and f4 is a focal length of the fourth lens 60. Through rational distribution of the focal length of the lens, the field angle of the projection optical device is favorably realized, and the overall performance of the projection optical device is improved.
As an alternative embodiment, the projection optics satisfy the following relationship:
Nd1≥1.53；Nd2≥1.80；Nd3≥1.63；Nd4≥1.85。
wherein the Nd1 is a refractive index of the first lens 30, the Nd2 is a refractive index of the second lens 40, the Nd3 is a refractive index of the third lens 50, and the Nd4 is a refractive index of the fourth lens 60. The reasonable distribution of the refractive index of the lens is helpful for improving the environmental adaptability of the system.
In a preferred embodiment, the first lens 30 has a lens thickness T1 of 1.0mm in the optical axis direction, the second lens 40 has a lens thickness T2 of 2.01mm in the optical axis direction, the third lens 50 has a lens thickness T3 of 1.0mm in the optical axis direction, and the fourth lens 60 has a lens thickness T4 of 1.92mm in the optical axis direction. The thickness of each lens is set in such a way, which contributes to improving the image quality of the system and shortening the overall length of the system.
In a preferred embodiment, a distance between the light incident surface 32 of the first lens 30 and the light emitting surface 41 of the second lens 40 along the optical axis direction is 0.1 mm; the distance between the light incident surface 42 of the second lens 40 and the light emitting surface 51 of the third lens 50 along the optical axis direction is 1.12 mm; the distance between the light incident surface 52 of the third lens element 50 and the light emitting surface 61 of the fourth lens element 60 along the optical axis direction is 0.94 mm. The distance between the lenses is set, which is helpful to improve the image quality of the system and shorten the whole length of the system.
Referring to fig. 2, as a preferred embodiment, the projection optical apparatus further includes a beam splitter prism 20, and the beam splitter prism 20 is disposed between the display unit 10 and the fourth lens 60. In this embodiment, the display unit 10 is a DMD or LCOS display chip, and an illumination light source is required, wherein one of the illumination modes is: the illumination light source emits light, the beam splitter prism 20 reflects the light of the illumination light source to the display unit 10, the light carries display information of the display unit 10 and is reflected, and then enters the fourth lens 60 through the beam splitter prism 20. If the display unit 10 uses an active light emitting display device, such as Mini/Micro-LED, Micro-OLED, the beam splitting prism 20 may not be used.
Referring to fig. 3, as a preferred embodiment, the projection optical apparatus further includes a mirror or a turning prism 70, and the mirror or the turning prism 70 is disposed on a side of the first lens 30 away from the second lens 40. The reflector or the turning prism 70 is used to change the direction of the light emitted from the first lens 30, so that the setting direction of the projection optical device can be changed, which is applicable to various situations, as shown in fig. 4 and 5, when the reflector or the turning prism 70 is correspondingly arranged in fig. 4, the whole setting direction of the projection optical device is arranged, and when the reflector or the turning prism 70 is not arranged in fig. 5, the whole setting direction of the projection optical device is arranged.
The specific design parameters of the projection optical device of the present embodiment are shown in table 1 below:
TABLE 1
Wherein, the utility model discloses the aspheric surface profile expression of each lens in each embodiment is:
in the above formula, z is the rise of the aspherical surface profile, and r is the radius of the aspherical surface, that is, r ═ sqrt (x) 2 +y 2 ) K is the coefficient of the quadric surface, c is the curvature, A 4 ～A 16 The coefficients of the high-order terms of the aspherical surface are shown in Table 2.
TABLE 2
The parameters to be explained are as follows:
the focal length f of the projection optics is 10.46 mm;
the focal length f1 of the first lens 30 is 163.95 mm;
the focal length f2 of the second lens 40 is 7.75 mm;
the focal length f3 of the third lens 50 is-4.66 mm;
the focal length f4 of the fourth lens 60 is 6.84 mm;
the thickness T1 of the first lens 30 along the optical axis direction is 1.0 mm;
the thickness T2 of the second lens 40 along the optical axis direction is 2.01 mm;
the thickness T3 of the third lens 50 along the optical axis is 1.0 mm;
the thickness T4 of the fourth lens 60 along the optical axis is 1.92 mm;
the thickness of the turning prism 70 is 6mm, and the thickness of the beam splitter prism 20 is 8 mm;
the total length TTL of the projection optics (from turning prism 70 to display unit 10) is 24.76 mm;
the distance between the turning prism 70 and the light-emitting surface 31 of the first lens 30 along the optical axis direction is 1.0 mm;
the distance between the light incident surface 32 of the first lens 30 and the light emitting surface 41 of the second lens 40 along the optical axis direction is 0.1mm (this data is the data of the thickness of the light incident surface 32);
the distance between the light incident surface 42 of the second lens 40 and the light emitting surface 51 of the third lens 50 along the optical axis direction is 1.12mm (this data is the data of the thickness of the light incident surface 42);
the distance between the light incident surface 52 of the third lens element 50 and the light emitting surface 61 of the fourth lens element 60 along the optical axis direction is 0.94mm (this data is the data of the thickness of the light incident surface 52);
the distance between the light incident surface 62 of the fourth lens 60 and the beam splitter prism 20 in the optical axis direction is 0.25mm (this data is data of the thickness of the light incident surface 62);
the center distance between the beam splitter prism 20 and the display unit 10 is 1.41 mm;
the maximum angle of view of the projection optics is 40 degrees and the half angle of view is 20 degrees.
Based on the above table 1 and table 2, the following provides a design result analysis of the projection optical apparatus according to the embodiment of the present invention.
Referring to fig. 6, fig. 6 is a graph of curvature of field and distortion corresponding to the projection optical device of the present embodiment, where the ordinate of the graph of curvature of field and distortion is the viewing angle, the maximum viewing angle is 20 degrees, the abscissa of curvature of field is mm, and the abscissa of distortion is percentage. It can be seen that the distortion of the maximum field angle is less than 1.5%, indicating that the distortion of the system is small.
Referring to fig. 7, fig. 7 is a lateral chromatic aberration diagram corresponding to the projection optical device of the present embodiment. The ordinate is the field angle and the abscissa is in microns, with smaller lateral chromatic aberration being better at the same field angle. FIG. 5 shows the corresponding lateral chromatic aberration at 486.1nm, 587.6nm, and 656.3 nm. Wherein, the wavelength of 587.6nm is taken as a zero standard.
Referring to fig. 8, fig. 8 is a graph of a modulation transfer function corresponding to the projection optical device of the present embodiment for evaluating the restoring capability of the scene details. The abscissa is the different spatial frequencies, the maximum spatial frequency is 112lp/mm, the spatial frequency is the maximum spatial frequency that a 0.26inch LCOS chip (display unit) can resolve, and the ordinate is the value of the modulation transfer function, dimensionless. The larger the corresponding MTF value, the better at the same spatial frequency.
Fig. 6 to 8 are design result analyses of the projection optical apparatus, which can be used to evaluate the quality of the lens design. The projection optical device described in this embodiment is not only small in size and light in weight, but also high in resolution, and can efficiently provide clear images.
The utility model also provides a wear-type augmented reality equipment, it is including wearing part and this embodiment projection optical device, projection optical device arranges in wear on the part. It may further comprise a waveguide device for guiding light emitted by the projection optics into the human eye. The wearing part and the waveguide device are common parts of the existing head-mounted display equipment, and the projection optical device adopts all the technical schemes of all the embodiments, so that the projection optical device at least has all the beneficial effects brought by the technical schemes of the embodiments, and the details are not repeated.
In the description of the present invention, it is to be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", and the like indicate orientations or positional relationships based on those shown in the drawings, and are merely for convenience of description and simplicity of description, and do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be construed as limiting the present invention. In the description of the present invention, "a plurality" means two or more unless otherwise specified.
The above-mentioned embodiments only represent some embodiments of the present invention, and the description thereof is specific and detailed, but not to be construed as limiting the scope of the present invention. It should be noted that, for those skilled in the art, without departing from the spirit of the present invention, several variations and modifications can be made, which are within the scope of the present invention.
Claims (10)
1. A projection optical apparatus, comprising:
the display unit, the fourth lens, the third lens, the second lens and the first lens are sequentially arranged along the light transmission direction; the first lens, the second lens and the fourth lens all have positive focal power, and the third lens has negative focal power;
the light incident surface of the first lens along the optical axis direction is a convex surface, and the light emergent surface along the optical axis direction is a concave surface;
the light incident surface and the light emergent surface of the second lens along the optical axis direction are convex surfaces;
the light incident surface and the light emergent surface of the third lens along the optical axis direction are both concave surfaces;
the light incident surface and the light emergent surface of the fourth lens along the optical axis direction are convex surfaces.
2. The projection optical apparatus according to claim 1, characterized in that:
the light incident surface and the light emergent surface of the first lens, the second lens, the third lens and the fourth lens along the optical axis direction are aspheric surfaces.
3. Projection optics according to claim 2, characterized in that the projection optics satisfy the following relation:
5.0≤f1/f≤20.0；
0.5≤f2/f≤1.5；
-0.3≤f3/f≤-1.0；
0.5≤f4/f≤1.0；
wherein f is a focal length of the projection optics, f1 is a focal length of the first lens, f2 is a focal length of the second lens, f3 is a focal length of the third lens, and f4 is a focal length of the fourth lens.
4. Projection optics according to claim 3, characterized in that the projection optics satisfy the following relation:
Nd1≥1.53；Nd2≥1.80；Nd3≥1.63；Nd4≥1.85；
wherein the Nd1 is a refractive index of the first lens, the Nd2 is a refractive index of the second lens, the Nd3 is a refractive index of the third lens, and the Nd4 is a refractive index of the fourth lens.
5. Projection optics according to claim 4, characterized in that:
first lens are 1.0mm along optical axis direction's lens thickness T1, second lens are 2.01mm along optical axis direction's lens thickness T2, third lens are 1.0mm along optical axis direction's lens thickness T3, fourth lens are 1.92mm along optical axis direction's lens thickness T4.
6. The projection optical apparatus according to claim 5, characterized in that:
the distance between the light incident surface of the first lens and the light emergent surface of the second lens along the optical axis direction is 0.1 mm; the distance between the light incident surface of the second lens and the light emergent surface of the third lens along the optical axis direction is 1.12 mm; the distance between the light incident surface of the third lens and the light emergent surface of the fourth lens along the optical axis direction is 0.94 mm.
7. Projection optics according to any one of claims 1-6, characterised in that: the display device further comprises a light splitting prism, and the light splitting prism is arranged between the display unit and the fourth lens.
8. Projection optics according to any one of claims 1-6, characterised in that: the lens is characterized by further comprising a reflecting mirror or a turning prism, wherein the reflecting mirror or the turning prism is arranged on one side, far away from the second lens, of the first lens.
9. A head-mounted augmented reality device comprising a wearing part and the projection optics of any one of claims 1-8, the projection optics being disposed on the wearing part.
10. The head-mounted augmented reality device of claim 9, wherein: the projection optical device further comprises a waveguide device which is used for guiding the light rays emitted by the projection optical device to enter human eyes.
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| CN202122355144.7U CN217156945U (en) | 2021-09-27 | 2021-09-27 | Projection optical device and head-mounted augmented reality equipment |
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| CN202122355144.7U CN217156945U (en) | 2021-09-27 | 2021-09-27 | Projection optical device and head-mounted augmented reality equipment |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116360077A (en) * | 2023-03-03 | 2023-06-30 | 广州瑞格尔电子有限公司 | Large-view-field short-focus projection lens and LCD projector |
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2021
- 2021-09-27 CN CN202122355144.7U patent/CN217156945U/en active Active
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116360077A (en) * | 2023-03-03 | 2023-06-30 | 广州瑞格尔电子有限公司 | Large-view-field short-focus projection lens and LCD projector |
| CN116360077B (en) * | 2023-03-03 | 2023-11-03 | 广州瑞格尔电子有限公司 | Large-view-field short-focus projection lens and LCD projector |
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