CN112859330A - Diffractive optical element for projecting starry sky effect, design method thereof, optical projection device and vehicle comprising same - Google Patents
Diffractive optical element for projecting starry sky effect, design method thereof, optical projection device and vehicle comprising same Download PDFInfo
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- CN112859330A CN112859330A CN202110190441.2A CN202110190441A CN112859330A CN 112859330 A CN112859330 A CN 112859330A CN 202110190441 A CN202110190441 A CN 202110190441A CN 112859330 A CN112859330 A CN 112859330A
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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
- G02B27/0012—Optical design, e.g. procedures, algorithms, optimisation routines
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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
- G02B27/42—Diffraction optics, i.e. systems including a diffractive element being designed for providing a diffractive effect
- G02B27/4205—Diffraction optics, i.e. systems including a diffractive element being designed for providing a diffractive effect having a diffractive optical element [DOE] contributing to image formation, e.g. whereby modulation transfer function MTF or optical aberrations are relevant
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B5/00—Optical elements other than lenses
- G02B5/18—Diffraction gratings
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B5/00—Optical elements other than lenses
- G02B5/18—Diffraction gratings
- G02B2005/1804—Transmission gratings
Abstract
The invention provides a design method of a diffraction optical element for projecting a starry sky effect, which comprises the following steps: s101: generating a target map of the diffractive optical element from a target light field range, wherein the target map comprises a background covering at least part of the target light field range, a first set of points in a first gray scale range, and a second set of points in a second gray scale range, wherein the first gray scale range is higher than the gray scale of the background, and the second gray scale range is higher than the first gray scale range; and S102: and designing the phase distribution of the microstructure pattern units of the diffraction optical element according to the target diagram.
Description
Technical Field
The present invention relates generally to the field of optical technology, and more particularly to a diffractive optical element capable of projecting a starry sky effect, a method for designing the same, an optical projection apparatus, and a vehicle including the same.
Background
In the conventional illumination scheme for projecting starry sky effect, a regular lattice, such as a regular lattice of 3 × 3, 5 × 5, 7 × 7, is designed by using diffractive optical elements DOE, and two DOEs are fabricated on two surfaces of the same substrate and are shifted by a certain angle from each other by using a double-sided etching or double-sided transfer method, so as to form a distribution of starry stars as shown in fig. 1. However, the above conventional designs have the following problems:
firstly, the light field FOV is formed by two regular dot matrixes of double-sided transfer printing, so that the light field of the finally obtained starry sky field is the convolution sum of the two light field FOVs, and the finally formed light field cannot be accurately controlled.
Secondly, the number of the light points and the light and shade alternate degree cannot be accurately designed, the dependence on processing is high, and parasitic points of the light points and the shade alternate degree are easy to participate in convolution, so that the points are dense and deviate from the original design.
The statements in this background section merely represent techniques known to the public and are not, of course, representative of the prior art.
Disclosure of Invention
In view of at least one of the drawbacks of the prior art, the present invention provides a method for designing a diffractive optical element for projecting a starry sky effect, comprising:
s101: generating a target map of the diffractive optical element from a target light field range, wherein the target map comprises a background covering at least part of the target light field range, a first set of points in a first gray scale range, and a second set of points in a second gray scale range, wherein the first gray scale range is higher than the gray scale of the background, and the second gray scale range is higher than the first gray scale range; and
s102: and designing the phase distribution of the microstructure pattern units of the diffraction optical element according to the target diagram.
According to an aspect of the invention, said step S101 comprises randomly distributing said first set of points and said second set of points within said target light field.
According to an aspect of the present invention, the gray scale value ranges from 0 to 255 are set, wherein the gray scale of the background ranges from 0 to 5, the first gray scale range is from 20 to 50, and the second gray scale range is from 100-.
According to one aspect of the invention, the design method further comprises adjusting the gray values of the background, the first group of points and the second group of points according to the computer simulation result to obtain a better starry sky effect.
According to an aspect of the invention, said step S101 comprises: generating random numbers, and randomly distributing the first group of points and the second group of points in the target light field range according to the random numbers.
The present invention also provides a diffractive optical element for projecting a starry sky effect, comprising:
at least one microstructure pattern unit capable of projecting a predetermined light field pattern;
wherein the preset light field pattern has: a background covering at least part of the target light field range;
a first set of points in a first gray scale range; and
a second set of points in a second gray scale range,
wherein the first gray scale range is higher than the gray scale of the background, and the second gray scale range is higher than the first gray scale range.
According to one aspect of the invention, the first and second sets of points are randomly distributed within the target light field.
According to an aspect of the present invention, the gray scale value ranges from 0 to 255 are set, wherein the gray scale of the background ranges from 0 to 5, the first gray scale range is from 20 to 50, and the second gray scale range is from 100-.
The present invention also provides an optical projection apparatus comprising:
a light source configured to emit a light beam;
a diffractive optical element as described above, arranged downstream of the light source to receive the light beam and project a preset light field pattern on a target plane, the preset light field pattern comprising a background, a first set of points in a first gray scale range and a second set of points in a second gray scale range.
According to an aspect of the invention, the optical projection apparatus further comprises a collimating optics disposed between the light source and the diffractive optical element for collimating and projecting the light beam emitted from the light source onto the diffractive optical element.
The present invention also provides a vehicle comprising:
the optical projection device as described above, installed inside the vehicle; and
wherein the optical projection device is configured to project a preset light field pattern on a roof of the vehicle, the preset light field pattern comprising a background, a first set of points in a first gray scale range and a second set of points in a second gray scale range.
The design method described in the embodiments of the present invention can obtain a diffractive optical element that projects a starry sky effect, having a starcloud background (first level), a weak starlight spot (second level), and a strong starlight spot (third level) in a target light field. The strong star light spots and the weak star light spots can be randomly distributed in a target light field, or can be preset according to an actual starry sky effect diagram, or the strong star light spots and the weak star light spots can be respectively distributed in central symmetry in the target light field, wherein the gray scale or the brightness of different strong star light spots can be randomly changed, the gray scale or the brightness of different weak star light spots can also be randomly changed, and the brightness of the strong star light spots is greater than that of the weak star light spots. The brightness of the star cloud background can be randomly distributed in the target light field, and is less than that of the weak star light spot.
Drawings
The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention and not to limit the invention. In the drawings:
FIG. 1 illustrates a projection of a starry sky image formed by the prior art;
FIG. 2 illustrates a method of designing a diffractive optical element for projecting a starry sky effect, according to one embodiment of the present invention;
FIG. 3 shows a target diagram of a diffractive optical element according to one embodiment of the present invention;
FIG. 4 shows a starry sky effect projected by a diffractive optical element designed and manufactured based on the above-described embodiment of the present invention using green laser light;
FIG. 5 illustrates a diffractive optical element projecting a starry sky effect according to one embodiment of the present invention; and
FIG. 6 shows an optical projection device according to one embodiment of the present invention.
Detailed Description
In the following, only certain exemplary embodiments are briefly described. As those skilled in the art will recognize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention. Accordingly, the drawings and description are to be regarded as illustrative in nature, and not as restrictive.
In the description of the present invention, it is to be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", and the like, indicate orientations and positional relationships based on those shown in the drawings, and are used only 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 considered as limiting the present invention. Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, features defined as "first", "second", may explicitly or implicitly include one or more of the described features. In the description of the present invention, "a plurality" means two or more unless specifically defined otherwise.
In the description of the present invention, it should be noted that unless otherwise explicitly stated or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection, either mechanically, electrically, or in communication with each other; either directly or indirectly through intervening media, either internally or in any other relationship. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.
In the present invention, unless otherwise expressly stated or limited, "above" or "below" a first feature means that the first and second features are in direct contact, or that the first and second features are not in direct contact but are in contact with each other via another feature therebetween. Also, the first feature being "on," "above" and "over" the second feature includes the first feature being directly on and obliquely above the second feature, or merely indicating that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature includes the first feature being directly above and obliquely above the second feature, or simply meaning that the first feature is at a lesser level than the second feature.
The following disclosure provides many different embodiments or examples for implementing different features of the invention. To simplify the disclosure of the present invention, the components and arrangements of specific examples are described below. Of course, they are merely examples and are not intended to limit the present invention. Furthermore, the present invention may repeat reference numerals and/or letters in the various examples, such repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various embodiments and/or configurations discussed. In addition, the present invention provides examples of various specific processes and materials, but one of ordinary skill in the art may recognize applications of other processes and/or uses of other materials.
The embodiments of the present invention will be described in conjunction with the accompanying drawings, and it should be understood that the embodiments described herein are only for the purpose of illustrating and explaining the present invention, and are not intended to limit the present invention.
The invention provides a diffractive optical element DOE for projecting a starry sky effect and a design method thereof, which can accurately control the FOV size, arbitrarily set the number of starry sky points, control the effect of light and shade alternation of the number of light points and form a projected light field with at least three levels of starry sky effect.
Fig. 2 illustrates a method 100 for designing a diffractive optical element for projecting a starry sky effect according to an embodiment of the present invention, which is described in detail below with reference to the accompanying drawings.
In step S101: generating a target map of the diffractive optical element from a target light field range, wherein the target map comprises a background covering at least part of the target light field range, a first set of points in a first grey scale range, which is higher than the grey scale of the background, and a second set of points in a second grey scale range, which is higher than the first grey scale range.
Fig. 3 shows a target diagram of a diffractive optical element according to an embodiment of the present invention. When used for projecting a starry sky effect inside a vehicle, the range of the target light field is, for example, the entire roof of the vehicle, and the background of the target image may occupy the entire target light field range or may be a part of the target light field range. The background may be a solid background or, preferably, may have a predetermined pattern, for example, may simulate a starry cloud background in a starry sky effect.
As shown in fig. 3, a plurality of weak star points (a first group of points) and a plurality of strong star points (a second group of points) are distributed on the background, wherein the gray scale or brightness of the weak star points is higher than that of the background, and the gray scale or brightness of the strong star points is higher than that of the weak star points.
The description will be made taking gray scale as an example. For example, the gray scale value range is set to be 0-255, wherein the gray scale of the background can be between 0-5, the first gray scale range can be between 20-50, and the second gray scale range is between 100-255.
In step S102: and designing the phase distribution of the microstructure pattern units of the diffraction optical element according to the target diagram. The surface of the diffractive optical element is provided with one or more micro-structure pattern units, the micro-structure pattern units comprise step-shaped micro-nano structures, and the heights of the micro-nano structures correspond to different phase delay amounts, so that when incident light is incident on the diffractive optical element, the micro-nano structures with different heights can generate certain phase delay amounts to the incident light to modulate the incident light, and a preset light field is integrally projected.
After the target map is obtained in step S101, the phase distribution of the microstructure pattern units of the diffractive optical element can be designed by combining the parameters of the light source (e.g., the type, wavelength, etc. of the light source) and the relevant dimensional parameters (e.g., the distance between the light source and the diffractive optical element, the distance between the diffractive optical element and the target projection surface, etc.).
In step S101, the first set of points and the second set of points may preferably be randomly distributed within the target light field or within the background. For example, random numbers may be generated, according to which the first and second sets of points are randomly distributed within the target light field range or within the background to achieve a random distribution of the first and second sets of points within the target light field range. Or alternatively, the first and second sets of points may be distributed in terms of a constellation diagram over the background or within the target light field
According to a preferred embodiment of the present invention, after the step S102, a computer simulation may be performed to obtain a simulated light field projected by the diffractive optical element, and the gray values and distribution positions of the background, the first group of points and the second group of points are adjusted according to the result of the simulated light field to obtain a better starry sky effect.
The embodiment described above includes the first group of points and the second group of points, but the present invention is not limited thereto, and may further include a third group of points having a range of gray scale or brightness different from that of the first group of points and the second group of points, thereby simulating a more realistic starry sky effect. Or preferably the second set of dots is further subdivided into two sets of dots, each having a different grey scale range or brightness range.
When designing the diffractive optical element according to the above method, the FOV may be set to 30 ° by 30 °, and a 2-step design, a 4-step design, an 8-step design, or a 16-step design may be additionally employed.
The design method described above enables a diffractive optical element to be obtained that projects a starry sky effect, with a starcloud background (first level), weak starlight spots (second level), and strong starlight spots (third level) within the target light field. The strong star light spots and the weak star light spots can be randomly distributed in a target light field, or can be preset according to an actual starry sky effect diagram, or the strong star light spots and the weak star light spots can be respectively distributed in central symmetry in the target light field, wherein the gray scale or the brightness of different strong star light spots can be randomly changed, the gray scale or the brightness of different weak star light spots can also be randomly changed, and the brightness of the strong star light spots is greater than that of the weak star light spots. The brightness of the star cloud background can be randomly distributed in the target light field, and is less than that of the weak star light spot.
Fig. 4 shows a starry sky effect projected by irradiating a diffractive optical element designed and manufactured based on the above-described embodiment of the present invention with green laser light.
Fig. 5 shows a diffractive optical element 200 for projecting a starry sky effect according to an embodiment of the present invention, as shown in fig. 5, the diffractive optical element has a plurality of step-like micro-nano structures on a surface thereof, and forms one or more microstructure pattern units, and the microstructure pattern units are designed to project a preset light field pattern, such as the patterns with the starry sky effect shown in fig. 3 and 4.
The preset light field pattern has a background that is capable of covering at least part of the target light field range, a first set of points (weak star points as shown in fig. 3) in a first gray scale range (or luminance range) and a second set of points (strong star points as shown in fig. 3) in a second gray scale range (or luminance range). Wherein the first gray scale range is higher than the gray scale of the background, and the second gray scale range is higher than the first gray scale range.
The first and second sets of points may be randomly distributed within the target light field.
Taking the gray scale as an example, the gray scale value range is set to be 0-255, wherein the gray scale of the background is preferably between 0-5, the first gray scale range is preferably 20-50, and the second gray scale range is preferably 100-255.
The present invention also relates to an optical projection device 30, as shown in fig. 6, the optical projection device 30 comprising a light source 301 and a diffractive optical element 20 as described above, wherein the light source 301 is configured to emit a light beam, the diffractive optical element 20 being arranged downstream of said light source 301 to receive said light beam and project a preset light field pattern on a target surface 303, said preset light field pattern comprising a background, a first set of points in a first gray scale range and a second set of points in a second gray scale range. The diffractive optical element 20, upon receiving the light emitted from the light source 301, modulates the light emitted from the light source to project a predetermined light field pattern on the target surface 303. The target surface 303 is, for example, a roof of a vehicle interior or a wall of a building.
The light source 301 is preferably a laser light source, but other types of light sources are possible, such as an LED light source. The light source is preferably configured to emit divergent light of a non-planar wave
According to a preferred embodiment of the present invention, the optical projection device 30 further comprises a collimating optics arranged between the light source 301 and the diffractive optical element 20 for collimating and projecting the light beam emitted from the light source onto the diffractive optical element.
The invention also relates to a vehicle comprising an optical projection device 30 as described above, mounted inside said vehicle, for example on an a-pillar, a B-pillar, a C-pillar or a toggle pillow of the vehicle. The optical projection device is configured to project a preset light field pattern on a roof of the vehicle, the preset light field pattern comprising a background, a first set of points in a first gray scale range, and a second set of points in a second gray scale range. In addition, one or more of the optical projection devices 30 may be disposed on the vehicle, and each optical projection device 30 is configured to project a starry sky pattern in a localized area of the roof.
Finally, it should be noted that: although the present invention has been described in detail with reference to the foregoing embodiments, it will be apparent to those skilled in the art that changes may be made in the embodiments and/or equivalents thereof without departing from the spirit and scope of the invention. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (11)
1. A method of designing a diffractive optical element for projecting a starry sky effect, comprising:
s101: generating a target map of the diffractive optical element from a target light field range, wherein the target map comprises a background covering at least part of the target light field range, a first set of points in a first gray scale range, and a second set of points in a second gray scale range, wherein the first gray scale range is higher than the gray scale of the background, and the second gray scale range is higher than the first gray scale range; and
s102: and designing the phase distribution of the microstructure pattern units of the diffraction optical element according to the target diagram.
2. The design method of claim 1, wherein the step S101 comprises randomly distributing the first and second sets of points over the target light field.
3. The design method as described in claim 1, wherein the gray scale value ranges from 0 to 255, wherein the gray scale of the background is between 0 to 5, the first gray scale range is from 20 to 50, and the second gray scale range is from 100-.
4. The design method of claim 3, further comprising adjusting the gray values of the background, the first set of points, and the second set of points to obtain better starry sky effect based on computer simulation results.
5. The design method according to claim 2, wherein the step S101 includes: generating random numbers, and randomly distributing the first group of points and the second group of points in the target light field range according to the random numbers.
6. A diffractive optical element for projecting a starry sky effect, comprising:
at least one microstructure pattern unit capable of projecting a predetermined light field pattern;
wherein the preset light field pattern has: a background covering at least part of the target light field range;
a first set of points in a first gray scale range; and
a second set of points in a second gray scale range,
wherein the first gray scale range is higher than the gray scale of the background, and the second gray scale range is higher than the first gray scale range.
7. The diffractive optical element as claimed in claim 6, wherein said first and second sets of points are randomly distributed within said target light field.
8. The diffractive optical element as claimed in claim 6, wherein the gray scale value range is set to 0-255, wherein the gray scale of the background is between 0-5, the first gray scale range is 20-50, and the second gray scale range is 100-.
9. An optical projection device comprising:
a light source configured to emit a light beam;
the diffractive optical element as claimed in any one of claims 6 to 8, arranged downstream of said light source to receive said light beam and project a preset light field pattern on a target plane, said preset light field pattern comprising a background, a first set of points in a first gray scale range and a second set of points in a second gray scale range.
10. The optical projection device of claim 9, further comprising collimating optics disposed between the light source and the diffractive optical element for collimating and projecting the light beam emitted from the light source onto the diffractive optical element.
11. A vehicle, comprising:
the optical projection device according to claim 9 or 10, mounted inside the vehicle; and
wherein the optical projection device is configured to project a preset light field pattern on a roof of the vehicle, the preset light field pattern comprising a background, a first set of points in a first gray scale range and a second set of points in a second gray scale range.
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| CN202110190441.2A CN112859330A (en) | 2021-02-18 | 2021-02-18 | Diffractive optical element for projecting starry sky effect, design method thereof, optical projection device and vehicle comprising same |
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| CN202110190441.2A CN112859330A (en) | 2021-02-18 | 2021-02-18 | Diffractive optical element for projecting starry sky effect, design method thereof, optical projection device and vehicle comprising same |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114002768A (en) * | 2021-10-28 | 2022-02-01 | 江西欧迈斯微电子有限公司 | Optical element, projection module and electronic equipment |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114002768A (en) * | 2021-10-28 | 2022-02-01 | 江西欧迈斯微电子有限公司 | Optical element, projection module and electronic equipment |
| CN114002768B (en) * | 2021-10-28 | 2023-01-13 | 江西欧迈斯微电子有限公司 | Optical element, projection module and electronic equipment |
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