JP7030757B2 - An optical element including a plurality of regions, an optical system including the optical element, and a method of using the optical system. - Google Patents

Description

[Related application]
This application claims the priority of US Provisional Application No. 62 / 751,337 filed October 26, 2018, which is incorporated herein by reference in its entirety.

The present invention is an optical element having a main body having a surface, the surface has a plurality of regions periodically arranged by mosaic division, and each region of the plurality of regions has a random spatial distribution of a fine structure. Regarding optical elements. The optical system includes a light source and the above optical elements. Also disclosed are methods of making and using the above optical elements and optical systems.

For applications related to 3D scanning and gesture recognition, optical components are utilized to project light patterns over the scene during probing in connection with lasers, typically having wavelengths in the range of about 700 nm to about 1000 nm. The light pattern varies depending on the probing technique and can take various forms such as spots, lines, stripes, periodic grids such as checkers and the like.

Current techniques used to project light patterns rely on one or more diffractive optics to generate a particular diffractive order distribution. The diffractive optical element (DOE) is, of course, suitable for generating an optical pattern such as a diffractive pattern. DOE can be represented as a thin surface structure, usually one wavelength of light, capable of producing light patterns by interference and / or diffraction. Therefore, the light cone output from the DOE is defined by its minimum structure, which is inversely proportional. That is, the larger the spread angle, the smaller the required structure. However, DOEs are very susceptible to deviations from the design wavelength or manufacturing errors, and as a result, primarily 0th order diffraction is much stronger than other order diffractions, which is for 3D sensing applications. Causes unacceptable eye safe problems.

Patent Document 1 describes, for example, a DOE that generates a spot pattern. Random spot patterns often have to correspond to a wide angular range so that they can capture large parts of the scene. To illuminate a wide-angle scene, DOE requires a pattern with a very small structure. For example, in order to irradiate a range of 60 ° with a laser having a wavelength of 850 nm, a DOE having a minimum structure of 1.7 μm is required. The wider the angular range, the smaller the required structure. For maximum efficiency, DOE should be designed and manufactured as a grayscale continuous phase profile. However, it can be difficult to make a grayscale DOE with such a small structure. Instead, grayscale DOEs are generally made with a binary phase profile with an efficiency of up to 80%. The remaining energy is deprived of higher order diffraction orders outside the main light pattern. The use of multiple DOEs as disclosed in Patent Document 1 is useful in dealing with 0th order diffraction. However, the use of multiple DOEs has a deteriorating effect, with an actual effect of about 50% to 60%.

U.S. Pat. No. 8,630,039

In one aspect, it is an optical element having a body having a surface, the surface having a plurality of regions periodically arranged by mosaic division, and each region of the plurality of regions has a random spatial distribution of a fine structure. Optical elements are disclosed.

In another embodiment, it is an optical element including a light source and a body having a surface, the surface has a plurality of regions periodically arranged by mosaic division, and each region of the plurality of regions has a random spatial distribution of a fine structure. Also disclosed is an optical system comprising an optical element having the above.

In another aspect, it is a method using an optical system, which is a step of projecting an input beam from a light source onto an optical element, the optical element including a body having a surface, the surface being periodically arranged in mosaic division. Further disclosed is a method comprising a step of having a plurality of regions, each region of the plurality of regions having a random spatial distribution of fine structure, and a step of shaping an input beam into a target pattern.

Further features and advantages of the various embodiments are described in part in the following description and are partly apparent from the description, or can be found in the implementation of the various embodiments. The objectives and other advantages of the various embodiments are realized and achieved by the elements and combinations specifically noted in the description herein.

A plurality of embodiments and embodiments thereof of the present disclosure can be more fully understood from the detailed description and the accompanying drawings.

It is a figure of the optical element by one aspect of this invention. It is a figure of a plurality of regions periodically arranged by the mosaic division by one aspect of this invention. Shown are four microstructural regions periodically arranged in a repeating order in two orthogonal dimensions with the geometric outer boundaries of the squares of the mosaic division. FIG. 3 is a diagram of two microstructural regions with geometric outer boundaries of checkered squares. It is a figure of a plurality of regions periodically arranged by the mosaic division by another aspect of this invention. It is a figure of a plurality of regions periodically arranged by the mosaic division by another aspect of this invention. It is a figure of a plurality of regions periodically arranged by the mosaic division by another aspect of this invention. It is a figure of a plurality of regions periodically arranged by the mosaic division by another aspect of this invention. It is a figure of the optical system including the optical element by one aspect of this invention. FIG. 3 is a diagram of contour plots for various microstructures with geometric outer boundaries of squares, circles, hexagons, and pentagons. FIG. 3 is a contour plot diagram of the various microstructures defined by the saddle profile and their combinations. A target pattern having a speckle generated by an optical element according to one aspect of the present invention is shown. FIG. 5 is a diagram of continuous optical elements 10 in which the microstructure is characterized by focal length and the separation between the optical elements is consistent with the focal length. FIG. 3 is a diagram of an optical element in which the microstructure is characterized by a focal length and the thickness of the body between the mosaic split surfaces matches the focal length.

Throughout the specification and drawings, similar reference numerals indicate similar elements.

It should be understood that both the above overview and the following detailed description are merely descriptive and are intended to provide explanations for the various embodiments of the present teaching.

Therefore, an object of the present invention is an optical element capable of comprising a main body having a surface, the surface having a plurality of regions periodically arranged by mosaic division, and each region of the plurality of regions is a random structure having a fine structure. It is to provide an improved optical element having a spatial distribution. The optical system may include a light source 2 and an optical element 10.

The optical element can receive the input beam 5 from the light source 2 such as a laser. The optical element can project the input beam 5 as a target pattern 7 such as a random spot distribution. The optics may exhibit some properties such as the projection of the input beam 5 with high efficiency and / or the projection of the target patterns 7 and 9 having speckles with low 0th order diffracted light intensity. In one aspect, the optical element can project the input beam 5 as target patterns 7 and 9 having speckles that do not change even if the light source 2 moves with respect to the optical element.

FIG. 1 shows an optical element 10 according to an aspect of the present invention, which includes a main body 11 having a surface 12 such as a first surface 12a and a second surface 12b. FIG. 7 shows an optical system 100 that continuously includes a first optical element 10a and a second optical element 10b according to another aspect of the present invention. The description of each of the first optical element 10a and the second optical element 10b can be the same. For example, the first optical element 10a can include a first body 11a having a surface 12 such as a first surface 12a and a second surface 12b, and the second optical element 10b can include a first surface 12a and a second surface 12b. The second main body 11b having the surface 12 such as the above can be included. For simplicity, the disclosure herein relating to optics (10, 10a, and 10b), bodies (11, 11a, and 11b), and surfaces (12, 12a, and 12b) is otherwise indicated. Unless otherwise applicable, it is equally applicable to each component.

The body 11 of the optical element 10 may include an optical material. Non-limiting examples of optical materials suitable for use as the body 11 include glass or plastics, such as variants thereof such as UV curable polymers, polycarbonate, acrylics, quartz glass, silicon, or amorphous silicon. Other optical materials can also be used. Further, the body 11 can include a single optical material or a plurality of coupled optical materials in a plurality of layers, and these layers can include a substrate for mechanical support and another layer. The other layer is a layer for antireflection coating or another layer for other purposes such as ITO and metal coating.

The main body 11 of the optical element 10 may include a surface 12 such as a first surface 12a and a second surface 12b. The first surface 12a can be oriented in the opposite direction to the second surface 12b. In one aspect, the optical element 10 can include any number of surfaces 12, such as one surface, two surfaces, three surfaces, and the like. The number of surfaces 12 of the optical element 10 may vary depending on the shape of the optical element 10.

The surface 12 such as the first surface 12a and / or the second surface 12b of the main body 11 may have a plurality of regions 22 periodically arranged by mosaic division. Each region 20 of the plurality of regions 22 may have a geometric outer boundary that can abut (without gaps) the outer boundaries of adjacent regions of the plurality of regions 22. As shown in FIG. 2A, the plurality of regions 22 are periodically arranged in, for example, a 3 × 3 array. As shown in FIG. 2B, each region 20 as shown by A, B, C, D and the like can be arranged in a repeating order in two orthogonal dimensions of a plurality of regions 22. FIG. 2C shows two regions represented by different patterns arranged in a checkered pattern.

The geometric outer boundary of each region 22 of the plurality of regions 20 can be any polygon, such as a triangle, a square, a rectangle, a pentagon, a hexagon, a heptagon, an octagon, and the like. In one aspect, each region of the plurality of regions may have the same geometric outer boundary. As shown in FIG. 2A, each region 20 can have a square, and the plurality of regions 22 can also form a periodic arrangement of mosaic divisions in the shape of a square. In one aspect, the geometric outer boundary can be arbitrary in shape. Each region 20 may include a random spatial distribution of microstructures such as saddle-shaped microstructures. As shown in FIG. 3, each region 20 can have a hexagon, and the plurality of regions 22 can form an arbitrary arrangement of mosaic divisions in an arbitrary shape. In one example, each region 20 may contain a random spatial distribution of saddle-shaped microstructures.

In one aspect, two or more of the regions 22 may have different geometric outer boundaries in the mosaic division. As shown in FIG. 4, the first region 20a of the plurality of regions 22 may have a hexagonal geometric outer boundary. Of the plurality of regions 22, the second region 20b may have an elongated rhombic geometric outer boundary. The plurality of regions 22 include the first region 20a and the second region 20b, and the geometric outer boundaries of the first region and the second region are different. FIG. 5 shows a plurality of regions 22 in which the first region 20a has a pentagonal geometric outer boundary. Of the plurality of regions 22, the second region 20b has a hexagonal geometric outer boundary.

The mosaic division can be as simple as, for example, as shown in FIGS. 2A-3, where each region 20 of the plurality of regions 22 has the same geometric outer boundaries. In one aspect, the mosaic division may be complex, for example as shown in FIGS. 4-6, with two or more regions 20 (20a, 20b, 20c, 20d) of the plurality of regions 22 being different. It can have a geometric outer boundary. As shown in FIG. 6, the plurality of regions 22 have a first region 20a having a pentagonal geometric outer boundary, a second region 20b having a hexagonal geometric outer boundary, and an elongated rhombic geometry. It includes a third region 20c having an outer boundary and a fourth region 20d having a geometric outer boundary having an arbitrary shape such as a star shape.

Any number of regions 20 can be used in the plurality of regions 22. In addition or as an alternative, each region 20 of the plurality of regions 22 may have the same or different random spatial distribution of microstructures. The regions 20 of the plurality of regions 22 may be arranged in a periodic arrangement so as to form a mosaic division that obtains the best contrast in the target patterns 7 and 9.

Each region 20 may have different random spatial distributions from each other. To be clear, each region 20 can be formed by a random spatial distribution of microstructure within the region 20. The random distribution of the microstructure can be based on the size of the region, the size of the microstructure, other variables, and combinations thereof. The random spatial distribution of the microstructure within each region 20 can minimize the periodic artifacts of target patterns 7 and 9, and can result in a random spot distribution of target patterns 7 and 9.

Referring again to FIG. 1, the optical element 10 may include a body 11 having a first surface 12a having a plurality of regions 22 periodically arranged in a mosaic division such as a first mosaic division. The body 11 may include a second surface 12b having a plurality of regions 22 periodically arranged in a mosaic division such as a second mosaic division that is the same as or different from the first mosaic division of the first surface 12a.

With reference to FIG. 7 again, the optical system 100 is disclosed. The optical system 100 may include a light source 2 and optical elements 10a and 10b. As shown in FIG. 7, the optical element 10a can include the first main body 11a, and the optical element 10b can include the second main body 11b. Each of the first main body 11a and the second main body 11b may be as described above with respect to the optical element 10 of FIG. For example, the first main body 11a can have a surface 12a having a plurality of regions 22 periodically arranged in a mosaic division such as the first mosaic division, and each region 20 of the plurality of regions 22 has a random structure. It has a spatial distribution. As another example, the second main body 11b can have a surface 12b having a plurality of regions periodically arranged in a mosaic division such as a second mosaic division, and each region 20 of the plurality of regions 22 has a fine structure. Has a random spatial distribution of. In this way, the first main body 11a can receive the input beam 5 from the light source 2 and output the target pattern 7 based on the first mosaic division. The second main body 11b can receive the target pattern 7 and output the second target pattern 9 based on the second mosaic division.

Target if a single body 11 has two surfaces 12a, 12b (FIG. 1), or if the first body 11a has a first surface 12a and the second body 11b has a second surface 12b (FIG. 7). It may be possible to extend the angular range of patterns 7 and 9. In this case, one of the surfaces 12a and 12b may take the form of a microlens array.

Referring again to FIG. 2A, the dashed squares indicate regions 20 of the plurality of regions 22, where each region 20 has a random spatial distribution of microstructure. In one aspect, each region 20 of the plurality of regions 22 has the same random spatial distribution of microstructure. In another aspect, two or more of the plurality of regions 22 have a random spatial distribution with different microstructures. As shown in FIG. 7, the random spatial distribution of the fine structure can shape the input beam 5 from the light source 2 such as the coherent light source into the target patterns 7 and 9. The microstructure can be described in a variety of methods such as micro-replication, thermal embossing, injection molding, reactive ion etching, or ion beam milling, or single point laser drawing, eg, as described in US Pat. No. 6,410,213. Can be formed by.

The microstructure can be defined in analytical or numerical form. For example, the microstructure can take the form of a lens with a radius of curvature, a conic constant, and possibly an aspheric coefficient. A. Betzold, GM Morris, and TRM Sales's publication "Efficient Structured Light Generator" (Frontiers in Optics 2016, OSA Technical Digest (Optical Society of America, 2016), paper FTu5A.4) includes radius of curvature and conic constants. Disclosed are microlenses based on a conical profile substantially represented by. However, by using a saddle-shaped lens or microstructure as described in Sales US Pat. No. 7,831,054, which is incorporated herein by reference, alone or in combination with a conical lens. It was found that further improvement can be obtained by being able to generate a non-uniform spot pattern. The microstructure of each region 20 may include a saddle shape. A microstructure other than the saddle shape may be used in each region 20.

The saddle-shaped microstructure can have a sag function defined as the following equation.

In the simplest case, α is a real constant, R _x and R _y are radii of curvature, κ _x and κ _y are conic constants, and p is a real number. The microstructure can also be defined as the following equation.

s (x, y) = αxy (2)

In the equation, α is also a real constant in this case as well. From their appearance, the microstructure represented by the equations (1) and (2) is a saddle-shaped lens.

FIG. 8 shows contour plots of microstructures with geometric outer boundaries of circles, squares, hexagons, and pentagons. Geometric outer boundaries can be mathematically defined by one function and general boundary functions, including irregular boundaries, polygonal boundaries, and arbitrary shape boundaries. FIG. 9 shows a contour diagram of the saddle-shaped microstructure as represented by the formulas (1) and (2) and its combination with the square boundary. Other relevant properties of the saddle-shaped microstructure are described in US Pat. No. 7,831,054, the disclosure of which is incorporated herein by reference.

As described above, the optical system 100 can generate target patterns 7 and 9 having a random spot distribution. Optical system 100 may also include other components such as sensors and computer algorithms for scene scanning and depth profiling.

The target patterns 7 and 9 may be a random spot distribution according to a random spatial distribution of the fine structure in each of the regions 20 of the plurality of regions. The random spatial distribution of the fine structure allows the input beam 5 from the light source 2 to be shaped into the target patterns 7 and 9 having speckles. The random spot distribution can span a particular angular range and may be the same or different in the two vertical directions. Such a random spot distribution with low 0th order diffracted light intensity and speckles fixed to the illumination motion can help provide structured light for 3D sensing applications.

In one aspect, each region 20 in the mosaic division is to increase the contrast of the target patterns 7 and 9 and to fix the speckles in the target patterns 7 and 9 so as not to change with the movement of the input beam 5 with respect to the optical element 10. One cycle, which defines the periodic arrangement of optics, can be made smaller than the size of the input beam 5.

The target patterns 7 and 9 can be generated so that the 0th order diffracted light is indistinguishable from the diffracted light of other order of interest in the random spot distribution in terms of intensity. The 0th order diffracted light intensity may provide the same amount of energy as any other spot in a random spot distribution. In this way, any problems with iSafe can be eliminated. In addition, usually a single surface pattern can be used to generate target pans 7 and 9 that ensure high efficiency. A plurality of continuously used optical elements 10a and 10b as shown in the optical system of FIG. 7 are used for other reasons such as to increase the effective range of the input beam 5 beyond the range that can be manufactured by the existing manufacturing method. can do. Under such conditions, one of the optical elements 10a and 10b may be a simple microlens array.

Each region 20 of the plurality of regions 22 can determine the angle separation between the two spots by the diffraction grating equation (vertical incident).

In the equation, θ _m is the diffraction angle of order m, λ is the wavelength of the input beam, and Λ is the lattice period. The overall mosaic split geometry can be directly correlated with the random spatial distribution of the microstructure. For example, a square array mosaic division (see, eg, FIGS. 2A-2C) produces a diffraction order on a square grid. Similarly, the hexagonal grid mosaic division (see, eg, FIG. 3) produces an order on the hexagonal grid. The angular spacing varies depending on the grid period, which may be the same or different along different directions. The random spatial distribution of the fine structure can generate a complex random spot distribution according to the periodic arrangement of each region 20 in the plurality of regions 22 for forming the mosaic division. The mosaic split geometry can determine the spot geometry, but each region 20 of the plurality of regions 22 determines the distribution of power among the various diffraction orders. In other words, the microstructure within each of the regions 20 has a diffraction order that produces a random spot pattern by being "turned on or off".

The method of making the optics may include selecting the periodic arrangement of the plurality of regions 22 to form a mosaic division. The method also includes allocating each region within the plurality of regions 22 to form a grid period. The method also includes a step of randomly spatially distributing the microstructure within each region 20 to form a plurality of regions. In one aspect, the microstructure within each region may include the saddle-shaped microstructure alone or in conjunction with other shaped microstructures.

Ultrastructures such as those described in US Pat. No. 7,831,054 can generate random speckle patterns when used alone. In other words, the region 20 of the fine structure can generate low-resolution target patterns 7 and 9 having speckles when the input beam 5 is received from the light source 2 such as a laser. The speckle pattern may change depending on the specific location of each region 20 that receives the input beam 5.

The periodic arrangement of the plurality of regions 22 for forming the mosaic division can prevent the movement of the target patterns 7 and 9 having speckles when the light source 2 moves with respect to the fine structure. In this case, it can be said that the target patterns 7 and 9 are stationary at predetermined positions. Further, the periodic arrangement of the plurality of regions 22 may lead to an improvement in the contrast of the target patterns 7 and 9 useful for 3D sensing applications. FIG. 10 shows photographs from target patterns 7 and 9 having speckles obtained by actually mounting the optical element 10 when illuminated by a light source 2 such as a laser having a wavelength of 633 nm.

The microstructure within each region 20 may have a particular focal length. In one aspect, the focal length on the first surface 12a side is on the second surface 12b side, regardless of whether the two optical elements 10a and 10b (FIG. 11) are used continuously or a single optical element 10 (FIG. 12). Can match the focal length of. Since they are mirror-symmetrical, each microstructure of the optical element 10 faces the other mirror image when they are arranged so as to face each other.

A method using an optical system 100, which is a step of projecting an input beam 5 from a light source 2 onto an optical element 10. The optical element 10 includes a main body 11 having a surface 12, and the surface 12 is periodically divided into mosaics. Also disclosed is a method including a step of having a plurality of arranged regions 22 and each region 20 of the plurality of regions 22 having a random spatial distribution of a fine structure, and a step of shaping the input beam 5 into target patterns 7 and 9. Will be done. The method may also include fixing the speckle from the random spatial distribution of the microstructure so that it does not change with the movement of the input beam 5 with respect to the optical element 10.

This scope disclosure shall be construed in a broad sense. The present disclosure is intended to disclose equivalents, means, systems, and methods for achieving the devices, operations, and mechanical actions disclosed herein. With respect to each disclosed configuration, diffractive optical element, optical system, method, means, mechanical element, or mechanism, the present disclosure is equivalent to implement many aspects, mechanisms, and configurations disclosed herein. It is also intended to include and teach objects, means, systems, and methods in their disclosure. In addition, the present disclosure considers one configuration and many aspects, features, and elements thereof. Such configurations can be dynamic in their use and operation, and the present disclosure relates to the equivalents, means, systems, and methods of the configuration and / or use of pigments to be manufactured and herein. It is intended to include many aspects thereof that are consistent with the description and intent of the actions and functions disclosed in. The scope of claims of the present application shall be construed in a broad sense as well.

The description of the invention herein is intended to be within the scope of the invention, as many embodiments thereof are merely exemplary in nature and thus variants that do not deviate from the gist of the invention are within the scope of the invention. Will be done. Such variants shall not be deemed to deviate from the spirit and scope of the invention.

Claims (16)

It ’s an optical element,
It comprises a body having a surface, the surface having a plurality of regions periodically arranged in a mosaic division.
Each region of the plurality of regions has a geometric outer boundary, and two or more regions of the plurality of regions have geometric outer boundaries having different polygonal shapes, and each region of the plurality of regions has a different geometric outer boundary. The geometric outer boundary of is in contact with the geometric outer boundary of the region adjacent to the region, and each region of the plurality of regions has a random spatial distribution of microstructure, and the microstructure is saddle-shaped. An optical element. The optical element according to claim 1, wherein each region can be arranged in a repeating order in two orthogonal dimensions. The optical element according to claim 1, wherein each region of the plurality of regions has the same random spatial distribution of a fine structure. The optical element according to claim 1, wherein two or more of the plurality of regions have a random spatial distribution having different microstructures. The optical element according to claim 1, wherein the main body having a surface is an optical element including a first surface and a second surface. The optical element according to claim 5 , wherein the second surface is in the opposite direction to the first surface. In the optical element according to claim 1, the main body also has a second surface, the second surface has a plurality of regions periodically arranged by a second mosaic division, and each of the plurality of regions. An optical element whose region has a random spatial distribution with a fine structure. It ’s an optical system,
Light source and
An optical element comprising a body having a surface, wherein the surface has a plurality of regions periodically arranged by mosaic division, each region of the plurality of regions has a geometric outer boundary, and the plurality of regions. Two or more of the regions have different geometric outer boundaries of polygonal shape, and the geometric outer boundary of each region of the plurality of regions is the geometric outer boundary of the region adjacent to the region. An optical system in which each region of the plurality of regions has a random spatial distribution of a microstructure, and the microstructure is provided with an optical element having a saddle shape. In the optical system according to claim 8, the light source is an optical system that is a coherent light source. In the optical system according to claim 9, the coherent light source is an optical system that is a laser. In the optical system according to claim 9, the optical element is an optical system that projects a target pattern according to a random spatial distribution of a fine structure. In the optical system according to claim 11, the target pattern is an optical system having a random spot distribution over a designated angle range. In the optical system according to claim 11, the target pattern is an optical system that differs in two vertical directions. The optical system according to claim 8, wherein the period defining the periodic arrangement is smaller than the size of the input beam from the light source in order to improve the contrast of the target pattern and fix the speckle. It is a method that uses an optical system.
A step of projecting an input beam from a light source onto an optical element, wherein the optical element includes a body having a surface, the surface having a plurality of regions periodically arranged by mosaic division, and each of the plurality of regions. The regions have geometric outer boundaries, two or more of the plurality of regions have different geometric outer boundaries of polygonal shape, and the geometric outer boundaries of each region of the plurality of regions. However, the step is in contact with the geometric outer boundary of the region adjacent to the region, each region of the plurality of regions has a random spatial distribution of microstructure, and the microstructure is saddle-shaped.
A method comprising shaping the input beam into a target pattern. The method of claim 15, further comprising fixing the speckle from the random spatial distribution of the microstructure so that it does not change with the movement of the input beam to the optical element.

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