JP6174355B2 - Diffractive optical element, diffractive optical element manufacturing method, diffractive optical element design apparatus, and object detection apparatus - Google Patents

Description

  The present invention relates to a diffractive optical element, a diffractive optical element manufacturing method, a diffractive optical element design apparatus, and an object detection apparatus.

An optical instrument provided with a diffraction grating may be used for spectroscopy. As described in Non-Patent Document 1, the interference fringes generated by the spectrum of the diffraction grating are based on the following formula (1).
Nλ / d = sin θ _N (1)
Where λ is the wavelength of the light, d is the pitch length of the diffraction grating, and θ _N where the interference fringes are generated is the angle at which the interference fringes occur in the Nth-order light (where N is an integer).

  An optical apparatus including such a diffraction grating may be used to form a specific pattern using primary light. Non-Patent Document 2 shows that a pattern indicating a person's name is projected on a screen by primary light generated by a computer generated hologram (CGH). Non-Patent Document 2 also describes suppressing the zero-order light diffraction efficiency of CGH.

Patent Document 1 describes a method for widening the irradiation range of diffracted light in a diffraction grating. In the method described in Patent Document 1, the pitch length Λ in the diffraction grating is set to about the wavelength λ of light. In this way, as is clear from equation (1), as compared with the case where the pitch length d is longer than the wavelength of light lambda, the angle theta _m increases. If the angle theta _m is thus large, the irradiation range of the diffracted light in the diffraction grating becomes wider ones.

JP 2006-189695 A

Donald C. O'Shea, Thomas J. Suleski, Alan D. Kathman, Dennis W. Prather, "Diffractive Optics: Design, Fabrication, and Test,", SPIE Tutorial Texts in Optical Engineering Vol. TT62, (SPIE Publications, 2003 ) Koshiko Ogura, Suzuki et al., Takehiko Nakai, Junichi Maruyama, Tanabe, Hiroki Sasaki, Teruhiro Shiono, “Introduction to Diffractive Optical Element Technology”, Japan Opto-Mechatronics Association (2006)

  A periodic pattern may be formed by the diffracted light in the diffraction grating. When such a periodic pattern is formed, it may be required to widen the irradiation range of the pattern. The present inventors studied to widen the irradiation range of the periodic pattern formed by the diffraction grating.

According to the present invention,
With a diffraction grating,
In the diffraction grating, when light having a single wavelength is diffracted by the diffraction grating and irradiated onto a curved surface, the image of the light forms a first pattern and a second pattern on the curved surface. The one curved surface is a spherical surface centered at a position where diffraction is generated in the diffraction grating,
The first pattern includes a first small pattern formed of m-order light (where m is a positive integer other than 0) in the diffraction grating, and the first small pattern is a predetermined direction of the spherical surface. Periodically arranged in a first period along
The second pattern includes a second small pattern formed of (m + 1) -order light in the diffraction grating, and the second small pattern has a second period equal to the first period along the predetermined direction of the spherical surface. periodically arranged in,
The first pattern includes a first first small pattern closest to the second pattern among the first small patterns,
The second pattern includes a first second small pattern closest to the first pattern among the second small patterns,
The first pattern and the second pattern are arranged along the predetermined direction of the spherical surface so that a periodic third pattern including the first small pattern and the second small pattern is formed. And
There is provided a diffractive optical element in which the first first small pattern and the first second small pattern are arranged at an interval equal to the first period and the second period .
According to the present invention,
With a diffraction grating,
In the diffraction grating, when light having a single wavelength is diffracted by the diffraction grating and irradiated onto a curved surface, the image of the light forms a first pattern and a second pattern on the curved surface. The one curved surface is a spherical surface centered at a position where diffraction is generated in the diffraction grating,
The first pattern includes a first small pattern formed of m-order light (where m is a positive integer other than 0) in the diffraction grating, and the first small pattern is a predetermined direction of the spherical surface. Periodically arranged in a first period along
The second pattern includes a second small pattern formed of (m + 1) -order light in the diffraction grating, and the second small pattern has a second period equal to the first period along the predetermined direction of the spherical surface. Periodically arranged in
The first pattern includes a third small pattern located between the first small pattern and the second pattern,
The second pattern includes a fourth small pattern located between the second small pattern and the first pattern,
The first pattern and the second pattern are formed as a periodic third pattern including the first small pattern, the second small pattern, the third small pattern, and the fourth small pattern. Arranged along the predetermined direction of the spherical surface,
The third small pattern and the fourth small pattern form a fifth small pattern,
The diffractive optics in which the first small pattern, the fifth small pattern, and the second small pattern are periodically arranged along the predetermined direction of the spherical surface with a period equal to the first period and the second period. An element is provided.
According to the present invention,
Designing a diffraction grating; and
Forming the diffraction grating on the substrate based on the design of the diffraction grating in the step of designing the diffraction grating; and
Including
In the step of designing a diffraction grating, the diffraction grating has a first pattern on the curved surface when the light of a single wavelength is diffracted by the diffraction grating and irradiated on the curved surface. A second pattern, and the one curved surface is a spherical surface centered on a portion where diffraction is generated by the diffraction grating,
The first pattern includes a first small pattern formed of m-order light (where m is a positive integer other than 0) in the diffraction grating, and the first small pattern is a predetermined direction of the spherical surface. Periodically arranged in a first period along
The second pattern includes a second small pattern formed of (m + 1) -order light in the diffraction grating, and the second small pattern has a second period equal to the first period along the predetermined direction of the spherical surface. periodically arranged in,
The first pattern includes a first first small pattern closest to the second pattern among the first small patterns,
The second pattern includes a first second small pattern closest to the first pattern among the second small patterns,
The first pattern and the second pattern are arranged along the predetermined direction of the spherical surface so that a periodic third pattern including the first small pattern and the second small pattern is formed. And
A method of manufacturing a diffractive optical element is provided in which the first first small pattern and the first second small pattern are arranged at an interval equal to the first period and the second period .
According to the present invention,
Designing a diffraction grating; and
Forming the diffraction grating on the substrate based on the design of the diffraction grating in the step of designing the diffraction grating; and
Including
In the step of designing a diffraction grating, the diffraction grating has a first pattern on the curved surface when the light of a single wavelength is diffracted by the diffraction grating and irradiated on the curved surface. A second pattern, and the one curved surface is a spherical surface centered on a portion where diffraction is generated by the diffraction grating,
The first pattern includes a first small pattern formed of m-order light (where m is a positive integer other than 0) in the diffraction grating, and the first small pattern is a predetermined direction of the spherical surface. Periodically arranged in a first period along
The second pattern includes a second small pattern formed of (m + 1) -order light in the diffraction grating, and the second small pattern has a second period equal to the first period along the predetermined direction of the spherical surface. Periodically arranged in
The first pattern includes a third small pattern located between the first small pattern and the second pattern,
The second pattern includes a fourth small pattern located between the second small pattern and the first pattern,
The first pattern and the second pattern are formed as a periodic third pattern including the first small pattern, the second small pattern, the third small pattern, and the fourth small pattern. Arranged along the predetermined direction of the spherical surface,
The third small pattern and the fourth small pattern form a fifth small pattern,
The diffractive optics in which the first small pattern, the fifth small pattern, and the second small pattern are periodically arranged along the predetermined direction of the spherical surface with a period equal to the first period and the second period. An element manufacturing method is provided.
According to the present invention,
A design unit for designing a diffraction grating for forming the first pattern;
A verification unit for verifying a position where the second pattern is formed by the diffraction grating designed by the design unit;
A correction unit that corrects the design of the diffraction grating designed by the design unit so that the position where the first pattern and the second pattern are formed is adjusted;
With
The first pattern and the second pattern are formed by an image of light having a single wavelength that is diffracted by the diffraction grating and applied to one curved surface, and the one curved surface is a portion where diffraction occurs in the diffraction grating. A spherical surface at the center,
The first pattern includes a first small pattern formed of m-order light (where m is a positive integer other than 0) in the diffraction grating, and the first small pattern is a predetermined direction of the spherical surface. Periodically arranged in a first period along
The second pattern includes a second small pattern formed of (m + 1) -order light in the diffraction grating, and the second small pattern has a second period equal to the first period along the predetermined direction of the spherical surface. periodically arranged in,
The first pattern includes a first first small pattern closest to the second pattern among the first small patterns,
The second pattern includes a first second small pattern closest to the first pattern among the second small patterns,
The correction unit moves the first pattern and the second pattern in the predetermined direction of the spherical surface so that a periodic third pattern including the first small pattern and the second small pattern is formed. the corrected design of the diffraction grating are arranged along,
A design apparatus for a diffractive optical element is provided in which the first first small pattern and the first second small pattern are arranged at an interval equal to the first period and the second period .
According to the present invention,
A design unit for designing a diffraction grating for forming the first pattern;
A verification unit for verifying a position where the second pattern is formed by the diffraction grating designed by the design unit;
A correction unit that corrects the design of the diffraction grating designed by the design unit so that the position where the first pattern and the second pattern are formed is adjusted;
With
The first pattern and the second pattern are formed by an image of light having a single wavelength that is diffracted by the diffraction grating and applied to one curved surface, and the one curved surface is a portion where diffraction occurs in the diffraction grating. A spherical surface at the center,
The first pattern includes a first small pattern formed of m-order light (where m is a positive integer other than 0) in the diffraction grating, and the first small pattern is a predetermined direction of the spherical surface. Periodically arranged in a first period along
The second pattern includes a second small pattern formed of (m + 1) -order light in the diffraction grating, and the second small pattern has a second period equal to the first period along the predetermined direction of the spherical surface. Periodically arranged in
The first pattern includes a third small pattern located between the first small pattern and the second pattern,
The second pattern includes a fourth small pattern located between the second small pattern and the first pattern,
The correction unit includes the first pattern and the second pattern so that a periodic third pattern including the first small pattern, the second small pattern, the third small pattern, and the fourth small pattern is formed. Correcting the design of the diffraction grating by arranging a second pattern along the predetermined direction of the spherical surface,
The third small pattern and the fourth small pattern form a fifth small pattern,
The diffractive optics in which the first small pattern, the fifth small pattern, and the second small pattern are periodically arranged along the predetermined direction of the spherical surface with a period equal to the first period and the second period. An element design device is provided.
According to the present invention,
A diffractive portion constituted by the diffractive optical element;
An irradiation unit for irradiating the diffractive optical element with light of a single wavelength;
A projection unit irradiated with a pattern of light diffracted by the diffraction grating of the diffractive optical element;
An imaging unit that continuously images temporally a pattern of light emitted from the diffractive optical element to the projection unit;
A storage unit for storing the light pattern captured by the imaging unit;
A determination unit that determines whether a light pattern at one time stored in the storage unit is different from a light pattern at another time stored in the storage unit;
Based on the determination result of the determination unit, a detection unit that detects the presence, shape, or position of an object irradiated with the light pattern diffracted by the diffraction grating of the diffractive optical element;
An object detection apparatus is provided.

  According to the present invention, the irradiation range of the periodic pattern formed by the diffraction grating can be widened.

It is a schematic diagram which shows the optical system in 1st Embodiment. It is a schematic diagram which shows the specific example of the 1st pattern and 2nd pattern which are formed in a spherical surface in 1st Embodiment. It is a schematic diagram which shows the specific example of the 1st pattern and 2nd pattern which are formed in a spherical surface in 1st Embodiment. It is a schematic diagram which shows the specific example of the 1st pattern and 2nd pattern which are formed in a spherical surface in 1st Embodiment. It is a schematic diagram which shows the specific example of the 1st pattern and 2nd pattern which are formed in a spherical surface in 1st Embodiment. It is a schematic diagram which shows the specific example of the 1st pattern and 2nd pattern which are formed in a spherical surface in 1st Embodiment. It is a schematic diagram which shows the specific example of the 1st pattern and 2nd pattern which are formed in a spherical surface in 1st Embodiment. It is a schematic diagram which shows the specific example of the 1st pattern and 2nd pattern which are formed in a spherical surface in 1st Embodiment. It is a schematic diagram which shows the specific example of the 1st pattern and 2nd pattern which are formed in a spherical surface in 1st Embodiment. It is a schematic diagram which shows the specific example of the 1st pattern and 2nd pattern which are formed in a spherical surface in 1st Embodiment. It is a flowchart which shows the design process of the diffractive optical element in 1st Embodiment. It is a block diagram which shows the structure of the design apparatus of the diffractive optical element in 1st Embodiment. It is a figure for demonstrating an example of the correction method of the design of the diffraction grating of the diffractive optical element in 1st Embodiment. It is process sectional drawing which shows the 1st example of the formation method of the diffractive optical element in 1st Embodiment. It is process sectional drawing which shows the 1st example of the formation method of the diffractive optical element in 1st Embodiment. It is process sectional drawing which shows the 1st example of the formation method of the diffractive optical element in 1st Embodiment. It is process sectional drawing which shows the 1st example of the formation method of the diffractive optical element in 1st Embodiment. It is process sectional drawing which shows the 1st example of the formation method of the diffractive optical element in 1st Embodiment. It is process sectional drawing which shows the 2nd example of the formation method of the diffractive optical element in 1st Embodiment. It is a block diagram which shows the structure of the detection apparatus of the object in 2nd Embodiment. It is a figure which shows the photograph of the pattern of the diffractive optical element in a reference example. 2 is a diagram showing a photograph of a pattern of a diffractive optical element in Example 1. FIG. 10 is a diagram showing a photograph of a pattern of a diffractive optical element in Example 2. FIG.

  Embodiments of the present invention will be described below with reference to the drawings. In all the drawings, similar constituent elements are denoted by common reference numerals, and description thereof is omitted as appropriate. Moreover, the figure is a schematic diagram and does not necessarily match the actual dimensional ratio.

(First embodiment)
FIG. 1 is a schematic diagram illustrating an optical system 100 according to the first embodiment. The optical system 100 includes a light source 102, a diffractive optical element (diffractive optical element) 104, and a screen 106. The light source 102 emits light 108 having a single wavelength. The light source 102 may be a laser or a light emitting diode. The light 108 may be visible light, infrared light, or ultraviolet light. The diffractive optical element 104 includes a diffraction grating (details of the diffraction grating of the diffractive optical element 104 will be described later). In the optical system 100, the light 108 emitted from the light source 102 reaches the diffractive optical element 104 as shown in FIG. Thereafter, the light 108 is diffracted by the diffraction grating of the diffractive optical element 104. A portion where the light 108 is diffracted by the diffraction grating of the diffractive optical element 104 is shown as a portion 112 in FIG. The diffracted light 110 travels toward the screen 106 as shown in FIG. In FIG. 1, as the diffracted light 110, diffracted lights 110a, 110b and 110c are exemplarily shown. The diffracted light 110 travels in a spherical wave shape centered on the point 112. In FIG. 1, a spherical surface 114 centered on the point 112 is shown. When the diffracted lights 110a, 110b, and 110c form a pattern having the same shape on the spherical surface 114, the diffracted light 110 travels in a spherical wave shape, and therefore the sizes of these patterns on the spherical surface 114 are the same. Of the diffracted light 110, the diffracted light traveling on the same straight line as the light 108 becomes zero-order light. The zero order light forms a dot-like pattern on the screen 106. The diffracted light 110 in this embodiment forms a pattern on the screen 106 without forming a pattern on the spherical surface 114. The surface of the screen 106 on which the diffracted light pattern is formed is flat. When the surface of the screen 106 is formed in a planar shape, the diffracted light that has reached the screen 106 has a longer optical path length from the point 112 to the screen 106 as the distance from the 0th-order light increases. In this case, the pattern of diffracted light formed on the screen 106 at a position shifted from the position where the zeroth-order light forms the pattern has a shape stretched in the shifted direction.

  The diffractive optical element 104 will be described in detail. The diffractive optical element 104 includes a diffraction grating. When the light 110 is diffracted by the diffraction grating and irradiated on the spherical surface 114, the diffraction grating of the diffractive optical element 104 forms the first pattern and the second pattern on the spherical surface 114. Designed to be. The light 110 is a single wavelength light. The spherical surface 114 is a spherical surface centered on the location 112. A portion 112 is a portion where diffraction occurs in the diffraction grating of the diffractive optical element 104. The first pattern includes a first small pattern. The first small pattern is formed of m-order light (where m is a positive integer other than 0) in the diffraction grating of the diffractive optical element 104. The first small patterns are periodically arranged along a predetermined direction of the spherical surface 114. The second pattern includes a second small pattern. The second small pattern is formed by the (m + 1) th order light in the diffraction grating of the diffractive optical element 104. The second small patterns are periodically arranged along a predetermined direction of the spherical surface 114. The first pattern and the second pattern are arranged along a predetermined direction of the spherical surface 114 so that a periodic third pattern is formed. The third pattern includes a first small pattern and a second small pattern.

  According to the diffractive optical element 104 in the present embodiment, the first pattern and the second pattern are integrated to form a periodic pattern. The irradiation range of such a periodic pattern is wider than the irradiation range of a periodic pattern formed by only one of the first pattern and the second pattern. According to this embodiment, the irradiation range of the periodic pattern formed by the diffraction grating can be widened.

  In the present embodiment, the first pattern and the second pattern may be formed not only on the spherical surface 114 but also on the surface of the flat screen 106. In this case, the first small patterns are arranged approximately periodically along a predetermined direction on the surface of the screen 106. The second small patterns are arranged approximately periodically along a predetermined direction on the surface of the screen 106. In the third pattern, the first small pattern and the second small pattern form a substantially periodic pattern. The substantially periodic pattern is a pattern arranged along a predetermined direction on the surface of the screen 106.

  In the present embodiment, as long as the diffractive optical element 104 is designed so that the first small pattern and the second small pattern are periodically formed on the spherical surface 114, the first small pattern and the second small pattern are As described above, the surface of the planar screen 106 may be formed “substantially periodically”. This is based on the fact that the diffracted light in the diffractive optical element 104 travels in a spherical wave shape. Even if the diffractive optical element 104 is designed such that the first small pattern and the second small pattern are periodically formed on the spherical surface 114, the first small pattern and the second small pattern are formed depending on the optical path length from the point 112 to the screen 106. The two small patterns may not satisfy the strict sense of periodicity on the surface of the planar screen 106. “Substantially periodic” in the case where the first small pattern and the second small pattern are formed on the surface of the planar screen 106 means that the periodicity in such a strict sense is not satisfied. .

  Details of the first pattern and the second pattern formed on the spherical surface 114 in the present embodiment will be described with reference to FIGS. 2 to 10 are diagrams showing specific examples of the first pattern and the second pattern formed on the spherical surface 114. FIG.

  FIG. 2 is a schematic diagram illustrating a first example of the first pattern and the second pattern. In FIG. 2, a first pattern P1 and a second pattern P2 are formed on the spherical surface 114. The first pattern P1 includes first small patterns P1a, P1b, and P1c. The first small patterns P1a, P1b, and P1c are formed by m-order light in the diffractive optical element 104. The first small patterns P1a, P1b, and P1c are periodically arranged along the direction DR. The second pattern P2 includes second small patterns P2a, P2b, and P2c. The second small patterns P <b> 2 a, P <b> 2 b, and P <b> 2 c are formed by the (m + 1) th order light in the diffractive optical element 104. The second small patterns P2a, P2b, and P2c are periodically arranged along the direction DR. The first pattern P1 and the second pattern P2 are arranged so that a periodic third pattern P3 is formed. The third pattern P3 includes first small patterns P1a, P1b and P1c, and second small patterns P2a, P2b and P2c.

  In the first example shown in FIG. 2, the first small patterns P1a, P1b and P1c and the second small patterns P2a, P2b and P2c are one-dimensional patterns. Specifically, the first small patterns P1a, P1b and P1c and the second small patterns P2a, P2b and P2c are formed in a dot shape. In this case, the dot size may be, for example, 1 μm or more and 10 mm or less. The interval between the dots may be, for example, 1 μm or more and 10 mm or less. In FIG. 2, the portions indicated by the alternate long and short dash line with “m” and “m + 1” indicate the formation ranges of the first pattern P1 and the second pattern P2, respectively (the same applies to FIGS. 3 to 10).

In the first pattern P1, the first small pattern P1a, P1b and P1c are arranged at a period _{C 1.} While in the second pattern P2, the second small pattern P2a, P2b and P2c are arranged at a period _{C 2.} In the first example, C ₁ = C ₂ is satisfied for the period C ₁ and the period C ₂ . Therefore, the interval between the first small patterns P1a and P1b, the interval between the first small patterns P1b and P1c, the interval between the second small patterns P2a and P2b, and the interval between the second small patterns P2b and P2c are equal to each other. . Furthermore, in the first example, these intervals are equal to the intervals between the first small pattern P1c and the second small pattern P2a. In the first example, the first small patterns P1a, P1b and P1c and the second small patterns P2a, P2b and P2c are formed on the same straight line along the direction DR. Therefore, in the first example shown in FIG. 2, the first small patterns P1a, P1b and P1c and the second small patterns P2a, P2b and P2c are integrated to form a periodic pattern.

  Thus, in the first example shown in FIG. 2, the third pattern P3 is formed in a periodic pattern. For this reason, in the first example shown in FIG. 2, the irradiation range of the periodic pattern can be widened.

  Next, a second example shown in FIG. 3 will be described. FIG. 3 is a schematic diagram illustrating a second example of the first pattern and the second pattern. The second example shown in FIG. 3 is the same as the first example shown in FIG. 2 except for the shapes of the first small patterns P1a, P1b and P1c and the second small patterns P2a, P2b and P2c.

  In the second example shown in FIG. 3, the first small patterns P1a, P1b and P1c and the second small patterns P2a, P2b and P2c are one-dimensional patterns. Specifically, the first small patterns P1a, P1b and P1c and the second small patterns P2a, P2b and P2c are formed in line segments. The lengths of the line segments in the first small patterns P1a, P1b and P1c and the second small patterns P2a, P2b and P2c are equal to each other. The line-shaped first small patterns P1a, P1b and P1c and the second small patterns P2a, P2b and P2c shown in FIG. 3 may be formed by continuously arranging dot-shaped patterns.

  In the second example shown in FIG. 3, the third pattern P3 is formed in a periodic pattern. For this reason, the irradiation range of a periodic pattern can be widened. And in the 2nd example shown by FIG. 3, the pattern of 1 period in the 3rd pattern P3 can be made into a line segment pattern.

  Next, a third example shown in FIG. 4 will be described. FIG. 4 is a schematic diagram illustrating a third example of the first pattern and the second pattern. The third example shown in FIG. 4 is the same as the first example shown in FIG. 2 except for the shapes of the first small patterns P1a, P1b and P1c and the second small patterns P2a, P2b and P2c.

  In the third example shown in FIG. 4, the first small patterns P1a, P1b and P1c and the second small patterns P2a, P2b and P2c are two-dimensional patterns. Specifically, the first small patterns P1a, P1b and P1c and the second small patterns P2a, P2b and P2c are formed in a square shape. And in the 3rd example shown by FIG. 4, each two-dimensional pattern is comprised by the dot-shaped pattern. In the present embodiment, the shape of each two-dimensional pattern is not limited to a square, but a circle, an ellipse, a polygon (for example, a triangle or a regular hexagon), a character (for example, A, B), or a number (for example, 2, 3).

  In the third example shown in FIG. 4, the third pattern P3 is formed in a periodic pattern. For this reason, the irradiation range of a periodic pattern can be widened. In the third example shown in FIG. 4, the one-cycle pattern in the third pattern P3 can be a two-dimensional pattern composed of dot-like patterns.

  Next, a fourth example shown in FIG. 5 will be described. FIG. 5 is a schematic diagram illustrating a fourth example of the first pattern and the second pattern. The fourth example shown in FIG. 5 is similar to the first example shown in FIG. 4 except that the first small patterns P1a, P1b and P1c and the second small patterns P2a, P2b and P2c are constituted by linear patterns. The same as the three examples. The first small patterns P1a, P1b and P1c and the second small patterns P2a, P2b and P2c may be formed by continuously arranging dot-like patterns.

  In the fourth example shown in FIG. 5, the third pattern P3 is formed in a periodic pattern as in the third example shown in FIG. For this reason, the irradiation range of a periodic pattern can be widened. In the fourth example shown in FIG. 5, the one-cycle pattern in the third pattern P3 can be a two-dimensional pattern constituted by a linear pattern.

  Next, a fifth example shown in FIG. 6 will be described. FIG. 6 is a schematic diagram illustrating a fifth example of the first pattern and the second pattern. The fifth example shown in FIG. 6 is the same as the first example shown in FIG. 2 except for the first small patterns P1a, P1b, P1c and P1d and the second small patterns P2a, P2b, P2c and P2d.

  In the fifth example shown in FIG. 6, the first small patterns P1a, P1b, P1c and P1d and the second small patterns P2a, P2b, P2c and P2d are two-dimensional patterns. Specifically, the first small patterns P1b and P1c and the second small patterns P2b and P2c are formed in a square shape. On the other hand, the first small patterns P1a and P1d and the second small patterns P2a and P2d are respectively formed in a part of the first small patterns P1b and P1c and the second small patterns P2b and P2c. And in the 4th example shown by FIG. 6, each two-dimensional pattern is comprised by the dot-shaped pattern. In the present embodiment, the shape of each two-dimensional pattern is not limited to a square, but a circle, an ellipse, a polygon (for example, a triangle or a regular hexagon), a character (for example, A, B), or a number (for example, 2, 3).

  In the fifth example shown in FIG. 6, a portion of the first pattern P1 adjacent to the second pattern P2 (first small pattern P1d) and a portion of the second pattern P2 adjacent to the first pattern P1 (second small pattern P2). Pattern P2a) is united to form pattern P12. The pattern P12 is a one-cycle pattern that is a periodic pattern in the third pattern P3. The pattern P12 may be formed using the translational symmetry in the diffracted light. In the diffraction grating, the pattern formed by the mth order light and the pattern formed by the (m + 1) th order light have a translational symmetry relationship. In the translational symmetry relationship, in the fifth example shown in FIG. 6, the first small patterns P1a, P1b, P1c and P1d correspond to the second small patterns P2a, P2b, P2c and P2d, respectively. In this case, the shape of the first small patterns P1a and P1d may be formed such that the shape of the first small pattern P1b or P1c is formed when the first small patterns P1a and P1d are combined. In this way, when the arrangement of the first pattern P1 and the second pattern P2 is appropriately determined, the pattern P12 is formed by the first small pattern P1d and the second small pattern P2a.

  Even in the fifth example shown in FIG. 6, the third pattern P3 can be formed in a periodic pattern. For this reason, the irradiation range of a periodic pattern can be widened. In the fifth example shown in FIG. 6, the one-cycle pattern in the third pattern P3 can be a two-dimensional pattern composed of dot-like patterns.

  Next, a sixth example shown in FIG. 7 will be described. FIG. 7 is a schematic diagram illustrating a sixth example of the first pattern and the second pattern. The sixth example shown in FIG. 7 is different from the first example shown in FIG. 6 except that the first small patterns P1a, P1b, P1c and P1d and the second small patterns P2a, P2b, P2c and P2d are composed of linear patterns. This is the same as the fifth example shown in FIG. The first small patterns P1a, P1b, P1c and P1d and the second small patterns P2a, P2b, P2c and P1d may be formed by continuously arranging dot-like patterns.

  In the sixth example shown in FIG. 7, the third pattern P3 is formed in a periodic pattern as in the fifth example shown in FIG. For this reason, the irradiation range of a periodic pattern can be widened. In the sixth example shown in FIG. 7, the one-cycle pattern in the third pattern P3 can be a two-dimensional pattern composed of linear patterns.

  Next, a seventh example shown in FIG. 8 will be described. FIG. 8 is a schematic diagram showing a seventh example of the first pattern and the second pattern. The seventh example shown in FIG. 8 is the same as the first example shown in FIG. 2 except for the first pattern P1 and the second pattern P2.

  In the seventh example shown in FIG. 8, the first pattern P1 is formed in a lattice shape, and the second pattern P2 is also formed in a lattice shape. The third pattern P3 is also formed in a lattice shape. In the seventh example shown in FIG. 8, the small patterns constituting the first pattern P1 and the second pattern P2 are dot-like patterns. In the seventh example shown in FIG. 8, similarly to the fifth example shown in FIG. 6, the portion of the first pattern P1 adjacent to the second pattern P2 and the second pattern P2 adjacent to the first pattern P1. The pattern P12 may be formed integrally with the portion. The pattern P12 is a one-cycle pattern that is a periodic pattern in the third pattern P3.

  In the seventh example shown in FIG. 8, the third pattern P3 is formed in a lattice pattern and is formed in a periodic pattern. For this reason, in the seventh example shown in FIG. 8, the irradiation range of the lattice-like periodic pattern can be widened.

  Next, an eighth example shown in FIG. 9 will be described. FIG. 9 is a schematic diagram illustrating an eighth example of the first pattern and the second pattern. The eighth example shown in FIG. 9 is the same as the seventh example shown in FIG. 8 except that the small patterns constituting the first pattern P1 and the second pattern P2 are constituted by linear patterns. . The linear small patterns constituting the first pattern P1 and the second pattern P2 may be formed by continuously arranging dot-like patterns.

  In the eighth example shown in FIG. 9, the third pattern P3 is formed in a lattice shape and in a periodic pattern, as in the seventh example shown in FIG. For this reason, in the eighth example shown in FIG. 9, the irradiation range of the lattice-like periodic pattern can be widened. And in the 8th example shown by FIG. 9, the 3rd pattern P3 can be comprised by a linear pattern.

  Next, a ninth example shown in FIG. 10 will be described. FIG. 10 is a schematic diagram illustrating a ninth example of the first pattern and the second pattern. The ninth example shown in FIG. 10 is the same as the first example shown in FIG. 2 except that the fourth pattern P4 is formed.

  In the ninth example shown in FIG. 10, m = 1 is satisfied. That is, the first pattern P1 is formed with primary light, and the second pattern P2 is formed with secondary light. The 0th pattern P0, the 1st pattern P1, and the 2nd pattern P2 are arranged along the direction DR so that the periodic 4th pattern P4 is formed. The fourth pattern P4 includes a zeroth pattern P0, first small patterns P1a, P1b and P1c, and second small patterns P2a, P2b and P2c.

  In the ninth example shown in FIG. 10, the interval between the 0th pattern P0 and the first small pattern P1a is the interval between the first small patterns P1a and P1b, the interval between the first small patterns P1b and P1c, and the first small pattern P1a. It is equal to the interval between the pattern P1c and the second small pattern P2a, the interval between the second small patterns P2a and P2b, and the interval between the second small patterns P2b and P2c. In the ninth example, the 0th pattern P0, the first small patterns P1a, P1b and P1c and the second small patterns P2a, P2b and P2c are formed on the same straight line along the direction DR. Therefore, in the ninth example shown in FIG. 10, the 0th pattern P0, the first small patterns P1a, P1b and P1c and the second small patterns P2a, P2b and P2c are integrated to form a periodic pattern. It will be.

  Thus, in the ninth example shown in FIG. 10, the fourth pattern P4 is formed in a periodic pattern. For this reason, in the ninth example shown in FIG. 10, the irradiation range of the periodic pattern can be widened.

  Each example shown in FIGS. 2 to 10 is an example of this embodiment. The shape and arrangement of the first pattern and the second pattern are not limited to the examples shown in FIGS. For example, if the fact that the pattern formed by each diffracted light in m ≧ 1 is in a translational symmetry relationship, the first pattern formed by m-order light and the second pattern formed by (m + 1) -order light are used. The pattern and the pattern formed by the (m + 2) order light may be integrated to form a periodic pattern. In addition, a pattern formed by each diffracted light from the 0th pattern formed by the 0th order light to the second pattern formed by the (m + 1) th order light may be integrated to form a periodic pattern. . Alternatively, the pattern formed by each diffracted light from the pattern formed by the primary light to the second pattern formed by the (m + 1) -order light without using the 0th-order light is integrated into a periodic pattern. A pattern may be formed. In each example shown in FIGS. 2 to 10, m = 1 may be satisfied.

Next, a method for manufacturing the diffractive optical element 104 in this embodiment will be described. The manufacturing method of the diffractive optical element 104 in the present embodiment includes the following design process and formation process.
Design process: Process for designing a diffraction grating Formation process: Process for forming a diffraction grating on the substrate 200 based on the design of the diffraction grating in the design process

(Design process)
In the design process included in the method of manufacturing the diffractive optical element 104 in the present embodiment, the diffraction grating is configured such that when the light 110 is diffracted by the diffraction grating and irradiated onto the spherical surface 114, the image of the light 110 is the spherical surface 114. The first pattern and the second pattern are designed to be formed. The light 110 is a single wavelength light. The spherical surface 114 is a spherical surface centered on the location 112. A portion 112 is a portion where diffraction occurs in the diffraction grating of the diffractive optical element 104. The first pattern includes a first small pattern. The first small pattern is formed by m-order light in the diffraction grating of the diffractive optical element 104. The first small patterns are periodically arranged along a predetermined direction of the spherical surface 114. The second pattern includes a second small pattern. The second small pattern is formed by the (m + 1) th order light in the diffraction grating of the diffractive optical element 104. The second small patterns are periodically arranged along a predetermined direction of the spherical surface 114. The first pattern and the second pattern are arranged along a predetermined direction of the spherical surface 114 so that a periodic third pattern is formed. The third pattern includes a first small pattern and a second small pattern.

  Details of the design process included in the method of manufacturing the diffractive optical element 104 in the present embodiment will be described with reference to FIGS.

  FIG. 11 is a flowchart showing design steps included in the method of manufacturing the diffractive optical element 104 in the present embodiment. First, the design process in the present embodiment includes a process of designing a diffraction grating for forming the first pattern (process S102). The first pattern is a pattern formed by the m-th order light of the diffraction grating of the diffractive optical element 104. The first pattern is formed by an image of light 110 that is diffracted by the diffraction grating of the diffractive optical element 104 and applied to the spherical surface 114. In step S102, the diffraction grating is designed so that the first pattern includes the first small pattern. The first small pattern is formed by the mth-order light of the diffraction grating in the diffractive optical element 104. The first small patterns are arranged along a predetermined direction of the spherical surface 114.

  Next, in the design process in the present embodiment, the position where the second pattern is formed is verified (process S104). The second pattern is a pattern formed by the diffraction grating designed in step S104. The second pattern is a pattern formed with the (m + 1) -order light of the diffractive optical element 104. The second pattern is formed by an image of the light 110 that is diffracted by the diffraction grating of the diffractive optical element 104 and applied to the spherical surface 114. In step S104, the diffraction grating is designed so that the second pattern includes the second small pattern. The second small pattern is formed by the (m + 1) -order light of the diffraction grating in the diffractive optical element 104. The second small patterns are arranged along a predetermined direction of the spherical surface 114.

  Next, in the design process in this embodiment, the design of the diffraction grating designed in step S104 is corrected (step S106). In step S106, the design of the diffraction grating is corrected so that the positions where the first pattern and the second pattern are formed are adjusted. Specifically, the design of the diffraction grating is corrected so that the first pattern and the second pattern form a periodic third pattern. The third pattern includes a first small pattern and a second small pattern. The first pattern and the second pattern are arranged along a predetermined direction of the spherical surface 114.

  A design apparatus 500 that executes the design process shown in FIG. 11 will be described with reference to FIG. FIG. 12 is a block diagram showing the configuration of the design apparatus 500 for the diffractive optical element 104 in the present embodiment. The design apparatus 500 includes an input unit 502, a design unit 504, a verification unit 506, and a correction unit 508 as functional units. The input unit 502 has a function of transmitting a predetermined signal (for example, a signal including information on a predetermined condition) to the design unit 504, the verification unit 506, or the correction unit 508. The design unit 504 has a function of designing a diffraction grating that forms the first pattern (step S102). The verification unit 506 has a function of verifying the position where the second pattern is formed by the diffraction grating designed by the design unit 504 (step S104). The correction unit 508 has a function of correcting the design of the diffraction grating designed by the design unit 504 (step S106). The design apparatus 500 includes a design data storage unit 510 as a storage unit. The design data storage unit 510 stores data designed by the design unit 504 and data corrected by the correction unit 508.

The design unit 504 designs the diffraction grating that forms the first pattern in accordance with the signal input from the input unit 502. The first pattern is a pattern formed by m-order light of the diffraction grating of the diffractive optical element 104. The first pattern is formed by an image of light 110 that is diffracted by the diffraction grating of the diffractive optical element 104 and applied to the spherical surface 114. The design unit 504 designs the first pattern so that the first pattern includes the first small pattern. The first small pattern is formed by the mth-order light of the diffraction grating in the diffractive optical element 104. The first small patterns are arranged along a predetermined direction of the spherical surface 114. The signal input to the design unit 504 by the input unit 502 includes, for example, the period of the first small pattern in the first pattern, the formation position of the first pattern, the order (m) of the first pattern, and the formation area of the first pattern. The area and the distance from the location 112 to the spherical surface 114 are included. The design unit 504 designs a diffraction grating in which the first pattern is formed on the spherical surface 114 in accordance with the conditions input from the input unit 502. The design unit 504 outputs the diffraction grating data designed by the design unit 504 to the design data storage unit 510. The design data storage unit 510 stores the diffraction grating data output from the design unit 504. For example, Version of VirtualLab ^™ advanced 5.3.3 manufactured by Light Trans may be used as the design unit 504.

  The verification unit 506 verifies the position where the second pattern is formed. The second pattern is a pattern formed by the diffraction grating designed by the design unit 504. The second pattern is a pattern formed by the (m + 1) -order light of the diffraction grating of the diffractive optical element 104. The second pattern is formed by an image of the light 110 that is diffracted by the diffraction grating of the diffractive optical element 104 and applied to the spherical surface 114. The second pattern includes a second small pattern. The second small pattern is formed by the (m + 1) -order light of the diffraction grating in the diffractive optical element 104. The second small patterns are arranged along a predetermined direction of the spherical surface 114. The verification unit 506 may use translational symmetry between a pattern formed by m-order light and a pattern formed by (m + 1) -order light. When translational symmetry is used, the verification unit 506 reads data designed by the design unit 504 from the design data storage unit 510. The verification unit 506 verifies the position where the second pattern is formed based on the data and the pattern translational symmetry designed by the design unit 504. The verification unit 506 outputs data including the verification result (the second pattern is data including information on the position where the pattern is formed) to the design data storage unit 510. The design data storage unit 510 stores the data output from the verification unit 506.

  The correction unit 508 reads the data designed by the design unit 504 and the data verified by the verification unit 506 from the design data storage unit 510. Then, the correction unit 508 corrects the design of the diffraction grating designed by the design unit 504. The correcting unit 508 corrects the design of the diffraction grating so that a third pattern in which the first pattern and the second pattern are periodic is formed. The third pattern includes a first small pattern and a second small pattern. The first pattern and the second pattern are arranged along a predetermined direction of the spherical surface 114.

Details of the design data correction method performed by the correction unit 508 will be described with reference to FIG. FIG. 13 is a diagram for explaining an example of a method for correcting the design of a diffraction grating. In FIG. 13A, the first pattern P <b> 1 and the second pattern P <b> 2 are formed on the spherical surface 114 by the diffraction grating created based on the design not corrected by the correction unit 508. In FIG. 13B, a first pattern P1 and a second pattern P2 are formed on the spherical surface 114 by a diffraction grating created based on the design data corrected by the correction unit 508. 13A and 13B, the first pattern P1 and the second pattern P2 are periodically arranged along the direction DR. The first pattern P1 and the second pattern P2 are arranged at a period _{C 1} and cycle _{C 2,} respectively. For periods C ₁ and C ₂ , C ₁ = C ₂ is satisfied.

In the first pattern P1, as shown in FIG. 13A, the formation area A1 of the first pattern P1 is set. A pattern by m-th order light is formed in the formation region A1. The formation region A1 is provided in order to isolate the pattern of m-order light from patterns of other orders of diffracted light. As shown in FIG. 13A, the formation area A1 may be wider than the area where the first pattern P1 is actually formed. When the formation region A1 is formed in this way, the formation region A2 related to the second pattern P2 becomes wide due to the translational symmetry of the m-order light and the (m + 1) -order light. As a result, the distance D between the first pattern P1 and the second pattern P2 is large. Such formation regions A1 and A2 may be designed to make only the first pattern P1 stand out. The intensity of diffracted light in the diffraction grating tends to decrease as the order increases. By utilizing such a tendency, a desired pattern may be formed only by the first pattern P1. In this case, in order to obscure the second pattern P2 to be pattern noise, it is possible to increase the distance _{D (D> C 1 = C} 2). On the other hand, in the present embodiment, the formation areas A1 and A2 are corrected by the correction unit 508 as shown in FIG. In FIG. 13B, the formation regions A1 and A2 are corrected so that D = C ₁ = C ₂ is satisfied for the interval D. As a result, the first pattern P1 and the second pattern P2 are integrated to form a periodic pattern along the direction DR. The correction unit 508 is designed so that the first pattern P1 and the second pattern P2 in the diffraction grating formed by the design data from the design data storage unit 510 are arranged as shown in FIG. 13B. The design of the diffraction grating designed by is corrected. At this time, the design of the diffraction grating may be corrected by reducing the areas of the formation regions A1 and A2. As long as the first patterns P1 and P2 based on the design of the diffraction grating after correction by the correction unit 508 are integrated to form a periodic pattern, the formation regions A1 and A2 are corrected during correction of the diffraction grating design. The periods C ₁ and C ₂ may decrease with a decrease in the area. Alternatively, the design unit 504, as periodic pattern and the period C ₁ and C even ₂ is decreased to the first pattern P1 P2 by the correction of the correction portion 508 is formed in an integrated manner has the desired period A diffraction grating may be designed.

  The diffraction grating of the diffractive optical element 104 in the present embodiment is designed as described above. If the diffraction grating of the diffractive optical element 104 is formed based on the design in the above design process, the diffractive optical element 104 in which the first pattern and the second pattern are integrated to form a periodic pattern can be manufactured. it can.

(Formation process)
Next, the process of forming the diffractive optical element 104 in this embodiment will be described with reference to FIGS. 14 to 18 are process cross-sectional views illustrating a first example of a method for forming the diffractive optical element 104 in the present embodiment. FIG. 19 is a process cross-sectional view illustrating a second example of the method of forming the diffractive optical element 104 in the present embodiment.

  First, a first example of a method for forming a diffraction grating in the diffractive optical element 104 will be described. In the first example, a four-level diffraction grating is formed on the substrate 200. First, the substrate 200 is prepared (FIG. 14A). The substrate 200 may be a semiconductor substrate (for example, a silicon substrate), a glass substrate, or a quartz substrate. Next, a resist film 202a is formed on the substrate 200 (FIG. 14B). The resist film 202a may be formed by spin coating.

  Next, the resist film 202a is exposed through the photomask 204a (FIG. 15A). The shape of the diffraction grating formed on the surface of the substrate 200 is defined by the photomask 204a and a photomask 204b described later. In the present embodiment, the shape of the diffraction grating is based on the design in the design process described above. This design can be reflected by the shape of the photomasks 204a and 204b. That is, the design of the diffraction grating in the above-described design process corresponds to designing the photomasks 204a and 204b. After the exposure, the substrate 200 and the resist film 202a are immersed in a developer. Thereby, the resist film 202a is developed as shown in FIG.

  Next, the substrate 200 is etched using the resist film 202a as a mask. For etching, dry etching may be used. After the substrate 200 is etched, the resist film 202a is removed (FIG. 16A). In the process shown in FIG. 16A, a two-level diffraction grating having a pitch length d is formed on the surface of the substrate 200. After the step shown in FIG. 16A, a resist film 202b is formed on the substrate 200 (FIG. 16B).

  Next, the resist film 202b is exposed through the photomask 204b (FIG. 17A). After the exposure, the substrate 200 and the resist film 202b are immersed in a developer. Thereby, the resist film 202b is developed as shown in FIG.

  Next, the substrate 200 is etched using the resist film 202b as a mask (FIG. 18A). For etching, dry etching may be used. After the substrate 200 is etched, the resist film 202a is removed (FIG. 18B). As a result, a four-level diffraction grating having a pitch length d is formed on the surface of the substrate 200.

  Next, a second example of a method for forming a diffraction grating in the diffractive optical element 104 will be described. In the second example, a blazed diffraction grating is formed on the substrate 200. In the second example, first, the steps shown in FIGS. 14A and 14B are performed. Thereafter, holographic exposure is performed on the resist film 202a. In the holographic exposure, plane wave light (eg, He—Cd laser light) is irradiated from two different directions onto the resist film 202a. By these lights, interference fringes are formed on the resist film 202a. As a result, a parallel line latent image having a sinusoidal cross-sectional exposure density is formed in the resist film 202a. When the exposed resist film 202a is developed, a resist film 202a ′ having a sine half-wave cross section remains on the substrate 200 (FIG. 19A). In the present embodiment, the shape of the diffraction grating is based on the design in the design process described above. This design can be reflected by the arrangement of the resist film 202a ′. That is, the design of the diffraction grating in the above-described design process corresponds to designing the shape and arrangement of the resist film 202a ′.

  After the formation of the resist film 202a ′, ion beam etching (the ion beam is schematically indicated by an arrow in FIG. 19B) is performed from an oblique direction on the surface of the substrate 200 (FIG. 19B). . The ion beam etching is performed until the resist film 202a ′ disappears. As a result, a blazed diffraction grating having a pitch length d is formed on the surface of the substrate 200 as shown in FIG.

  In the present embodiment, the diffractive optical element 104 is obtained by the above design process and formation process. In the diffractive optical element 104 according to this embodiment, the first pattern and the second pattern are integrated to form a periodic pattern. Thereby, it becomes possible to widen the irradiation range of a periodic pattern.

(Second Embodiment)
According to the diffractive optical element 104 in the first embodiment, a periodic pattern can be irradiated over a wide range. In the second embodiment, the diffractive optical element 104 is applied to an object detection apparatus. According to the object detection apparatus including the diffractive optical element 104, it is possible to detect an object in a wide range.

  An object detection apparatus 150 according to this embodiment will be described with reference to FIG. FIG. 20 is a block diagram illustrating a configuration of the object detection device 150. The detection device 150 includes an irradiation unit 152, a diffraction unit 154, a projection unit 156, an imaging unit 158, a storage unit 160, a determination unit 162, and a detection unit 164. The diffractive portion 154 is configured by the diffractive optical element 104 in the first embodiment. The irradiation unit 152 irradiates the diffraction unit 154 with light 166 having a single wavelength. The projection unit 156 is irradiated with a pattern of light 168. The pattern of the light 168 is a pattern of light diffracted by the diffraction grating of the diffraction unit 154. The imaging unit 158 continuously captures the pattern of the light 168 applied to the projection unit 156 in terms of time. The storage unit 160 stores the pattern of the light 168 picked up by the image pickup unit 158. The determination unit 162 determines whether the pattern of the light 168 at one time stored in the storage unit 160 is different from the pattern of the light 168 stored at the other time stored in the storage unit 160. The detection unit 164 detects the presence, shape, or position of the object irradiated with the light 168 based on the determination result of the determination unit 162.

  The light source 102, the diffractive optical element 104, and the screen 106 in FIG. 1 may be used for the irradiation unit 152, the diffraction unit 154, and the projection unit 156, respectively. In this case, the lights 166 and 168 will correspond to the lights 108 and 110 of FIG. In the present embodiment, the shape of the surface of the projection unit 156 (screen 106) is not limited to a specific shape as long as the diffracted light pattern of the diffraction unit 154 (diffractive optical element 104) is formed. For the order of diffracted light in the diffractive portion 154 (diffractive optical element 104), m = 1 may be satisfied. The light emitted from the irradiation unit 152 (light source 102) may be visible light, infrared light, or ultraviolet light.

  An object detection method by the detection device 150 will be described. It is assumed that when the projection unit 156 is irradiated with the light 168 pattern, the object passes or is placed in front of the projection unit 156 while receiving the light 168 pattern irradiation. In this case, the pattern of the light 168 has different shapes at a place where the object exists and a place where the object does not exist. This is based on the optical path length of the light 168. The optical path length of the light 168 from the object to the diffraction unit 154 is shorter than the optical path length of the light 168 from the projection unit 156 to the diffraction unit 154. As a result, the image of the light 168 at the location where the object is present is smaller than the image of the light 168 in the projection unit 156. In the present embodiment, the pattern of the light 168 is a periodic pattern. For this reason, the periodicity of the pattern of the light 168 is broken at a place where an object is present. The disruption of the periodicity of the pattern of the light 168 is captured by the imaging unit 158 and stored in the storage unit 160. Then, the determination unit 162 determines the collapse of the periodicity of the pattern of the light 168 via the imaging unit 158 and the storage unit 160. That is, the determination unit 162 refers to the storage unit 160, the time when the object does not exist before the projection unit 156 (one time) and the time when the object exists before the projection unit 156 (others) It is determined whether the pattern of the light 168 is different. The detection unit 164 detects the presence, shape, or position of the object based on the determination result of the determination unit 162. The presence and position of the object are detected by analyzing a place where the periodicity of the pattern of the light 168 has broken. On the other hand, the shape of the object is detected based on the degree of distortion of the image of the light 168 at the location where the periodicity of the image of the light 168 has broken.

  In the present embodiment, the diffractive optical element 104 is used for the diffractive portion 154. In the diffractive optical element 104, the first pattern and the second pattern are integrated to form a periodic pattern. Thereby, a periodic pattern can be formed in a wide range. The formation of a periodic pattern in a wide range means that the detection device 150 can detect an object in a wide range. Thus, the detection apparatus 150 in this embodiment can detect an object in a wide range.

(Example)
The diffraction grating of the diffractive optical element 104 is designed using Light Trans, Version of VirtualLab ^™ advanced 5.3.3. The pattern formed on the screen is verified by the diffraction grating formed based on the design. 21 to 23 are diagrams showing photographs of patterns formed on the screen by the diffraction grating of the diffractive optical element 104. FIG.

(Reference example)
FIG. 21 is a diagram showing a photograph of the pattern of the reference example. In the reference example, for the formula (1), the diffraction grating was designed with N = m = 1, d = 1.6 μm, and λ = 0.63 μm. In the reference example, the 0th-order light is irradiated at m = 0 and the diffraction angle θ ₀ = 0. In FIG. 21, a black circle light absorber is placed at the center where the 0th order light exists for the convenience of photographing (if there is 0th order light having an excessively high intensity, the pattern by the primary light becomes clear. Because it is not confirmed.) In FIG. 21, a region surrounded by a broken line is a formation region A1. An outer frame portion OR is formed outside the formation region A1. A primary light pattern is not formed on the outer frame portion OR. In the reference example, the pattern of the primary light was formed in the irradiation range of the primary diffraction angle θ ₁ = 11 degrees. In the reference example, when the distance from the diffractive optical element 104 to the screen is 1 m, an irradiation pattern of square primary light having a side of 0.48 m is formed.

Example 1
22 is a view showing a photograph of Example 1. FIG. In Example 1, the diffraction grating was designed so as to eliminate the outer frame portion OR in FIG. In Example 1, the diffraction grating was designed with d = 1.6 μm and λ = 0.63 μm in the formula (1). In Example 1, a pattern formed by zero-order light, a pattern formed by primary light, and a pattern formed by secondary light were integrated to form a periodic lattice-like pattern. (FIG. 22). The lattice pattern is formed by collecting a plurality of dot patterns. In the first embodiment, the 0th-order light is irradiated at m = 0 and the diffraction angle θ ₀ = 0. In FIG. 22, the pattern by the primary light is formed from the 0th order light to the white broken line. A pattern by secondary light is formed on the right side from the white broken line. In Example 1, when the distance from the diffractive optical element 104 to the screen was 1 m, the periodic lattice pattern was confirmed at a distance of 0.55 m from the 0th order light to the white circle in FIG. That is, a periodic grid pattern with a diameter of 1.1 m was formed. Even though the pitch length d and the wavelength λ of the diffraction grating were the same in the reference example and the example 1, the periodic pattern could be formed in the example 1 in a wider irradiation range than in the reference example.

(Example 2)
23 is a view showing a photograph of Example 2. FIG. Also in Example 2, the diffraction grating was designed so as to eliminate the outer frame portion OR in FIG. Also in Example 2, the diffraction grating was designed with d = 1.6 μm and λ = 0.63 μm in the formula (1). In Example 2, the pattern formed by zero-order light, the pattern formed by primary light, the pattern formed by secondary light, and the pattern formed by tertiary light are integrated, A periodic pattern was formed (FIG. 23). The periodic pattern is formed by a plurality of dot patterns. In Example 2, the 0th-order light is irradiated at m = 0 and the diffraction angle θ ₀ = 0. In FIG. 23, a pattern by the primary light is formed from the 0th order light to the white broken line on the left side. A pattern of secondary light is formed from the white broken line on the left side to the white broken line on the right side. Further, a pattern of tertiary light is formed on the right side of the white broken line on the right side. In Example 2, when the distance from the diffractive optical element 104 to the screen was 1 m, the periodic pattern was confirmed at a distance of 0.85 m from the 0th order light to the white circle in FIG. That is, a periodic lattice pattern having a diameter of 1.7 m was formed. Even though the pitch length d and the wavelength λ of the diffraction grating were the same in the reference example and the example 2, the periodic pattern could be formed in the example 2 in a wider irradiation range than in the reference example.

From the results of Examples 1 and 2 above, it was confirmed that the diffractive optical element 104 according to the first embodiment can form a periodic pattern over a wide range. As described above, the diffractive optical element 104 according to the first embodiment can form a periodic pattern over a wide range.
Hereinafter, examples of the reference form will be added.
1. With a diffraction grating,
In the diffraction grating, when light having a single wavelength is diffracted by the diffraction grating and irradiated onto a curved surface, the image of the light forms a first pattern and a second pattern on the curved surface. The one curved surface is a spherical surface centered at a position where diffraction is generated in the diffraction grating,
The first pattern includes a first small pattern formed of m-order light (where m is a positive integer other than 0) in the diffraction grating, and the first small pattern is a predetermined direction of the spherical surface. Periodically arranged along the
The second pattern includes a second small pattern formed of (m + 1) -order light in the diffraction grating, and the second small pattern is periodically arranged along the predetermined direction of the spherical surface,
The first pattern and the second pattern are arranged along the predetermined direction of the spherical surface so that a periodic third pattern including the first small pattern and the second small pattern is formed. Diffractive optical element.
2.1. The diffractive optical element according to claim 1,
A diffractive optical element in which m = 1.
3.1. Or 2. The diffractive optical element according to claim 1,
The first small pattern and the second small pattern are diffractive optical elements that are one-dimensional patterns.
4.1. Or 2. The diffractive optical element according to claim 1,
The diffractive optical element, wherein the first small pattern and the second small pattern are two-dimensional patterns.
5.4. The diffractive optical element according to claim 1,
A portion of the first small pattern adjacent to the second small pattern and a portion of the second small pattern adjacent to the first small pattern are integrated to form a periodic pattern in the third pattern. A diffractive optical element forming a pattern of one period.
6.1. The diffractive optical element according to claim 1,
The first pattern is formed in a lattice shape,
The second pattern is formed in a lattice shape,
The third pattern is a diffractive optical element formed in a lattice shape.
7.2. The diffractive optical element according to claim 1,
The 0th pattern, the 1st pattern, and the 2nd pattern formed by the 0th order light in the diffraction grating are periodic 1st patterns including the 0th pattern, the 1st small pattern, and the 2nd small pattern. A diffractive optical element arranged along the predetermined direction of the spherical surface so that four patterns are formed.
8.1. To 7. The diffractive optical element according to any of the above,
When the first pattern and the second pattern are irradiated on one plane,
The first small patterns are arranged substantially periodically along a predetermined direction of the one plane,
The second small patterns are arranged substantially periodically along the predetermined direction of the one plane,
In the third pattern, the diffractive optical element in which the first small pattern and the second small pattern form a substantially periodic pattern arranged along the predetermined direction of the one plane.
9. Designing a diffraction grating; and
Forming the diffraction grating on the substrate based on the design of the diffraction grating in the step of designing the diffraction grating; and
Including
In the step of designing a diffraction grating, the diffraction grating has a first pattern on the curved surface when the light of a single wavelength is diffracted by the diffraction grating and irradiated on the curved surface. A second pattern, and the one curved surface is a spherical surface centered on a portion where diffraction is generated by the diffraction grating,
The first pattern includes a first small pattern formed of m-order light (where m is a positive integer other than 0) in the diffraction grating, and the first small pattern is a predetermined direction of the spherical surface. Periodically arranged along the
The second pattern includes a second small pattern formed of (m + 1) -order light in the diffraction grating, and the second small pattern is periodically arranged along the predetermined direction of the spherical surface,
The first pattern and the second pattern are arranged along the predetermined direction of the spherical surface so that a periodic third pattern including the first small pattern and the second small pattern is formed. A method for manufacturing a diffractive optical element.
10. A design unit for designing a diffraction grating for forming the first pattern;
A verification unit for verifying a position where the second pattern is formed by the diffraction grating designed by the design unit;
A correction unit that corrects the design of the diffraction grating designed by the design unit so that the position where the first pattern and the second pattern are formed is adjusted;
With
The first pattern and the second pattern are formed by an image of light having a single wavelength that is diffracted by the diffraction grating and applied to one curved surface, and the one curved surface is a portion where diffraction occurs in the diffraction grating. A spherical surface at the center,
The first pattern includes a first small pattern formed of m-order light in the diffraction grating, and the first small pattern is periodically arranged along a predetermined direction of the spherical surface,
The second pattern includes a second small pattern formed of (m + 1) -order light in the diffraction grating, and the second small pattern is periodically arranged along the predetermined direction of the spherical surface,
The correction unit moves the first pattern and the second pattern in the predetermined direction of the spherical surface so that a periodic third pattern including the first small pattern and the second small pattern is formed. An apparatus for designing a diffractive optical element that corrects the design of the diffraction grating by arranging them along the line.
11.1. To 8. A diffractive portion composed of the diffractive optical element according to any of the above,
An irradiation unit for irradiating the diffractive optical element with light of a single wavelength;
A projection unit irradiated with a pattern of light diffracted by the diffraction grating of the diffractive optical element;
An imaging unit that continuously images temporally a pattern of light emitted from the diffractive optical element to the projection unit;
A storage unit for storing the light pattern captured by the imaging unit;
A determination unit that determines whether a light pattern at one time stored in the storage unit is different from a light pattern at another time stored in the storage unit;
Based on the determination result of the determination unit, a detection unit that detects the presence, shape, or position of an object irradiated with the light pattern diffracted by the diffraction grating of the diffractive optical element;
An object detection apparatus comprising:

DESCRIPTION OF SYMBOLS 100 Optical system 102 Light source 104 Diffractive optical element 106 Screen 108 Light 110 Light 110a Light 110b Light 110c Light 112 Location 114 Spherical surface 150 Detection apparatus 152 Irradiation part 154 Diffraction part 156 Projection part 158 Imaging part 160 Storage part 162 Determination part 164 Detection part 166 Optical 168 Optical 200 Substrate 202a Resist film 202a 'Resist film 202b Resist film 204a Photomask 204b Photomask 500 Design device 502 Input unit 504 Design unit 506 Verification unit 508 Correction unit 510 Design data storage unit P0 0th pattern P1 1st pattern P1a 1st small pattern P1b 1st small pattern P1c 1st small pattern P1d 1st small pattern P2 2nd pattern P2a 2nd small pattern P2b 2nd small pattern P2c 2nd small pattern P2d 2nd small pattern P3 Third pattern P4 Fourth pattern DR Direction A1 Formation area A2 Formation area OR Outer frame

Claims (13)

With a diffraction grating,
In the diffraction grating, when light having a single wavelength is diffracted by the diffraction grating and irradiated onto a curved surface, the image of the light forms a first pattern and a second pattern on the curved surface. The one curved surface is a spherical surface centered at a position where diffraction is generated in the diffraction grating,
The first pattern includes a first small pattern formed of m-order light (where m is a positive integer other than 0) in the diffraction grating, and the first small pattern is a predetermined direction of the spherical surface. Periodically arranged in a first period along
The second pattern includes a second small pattern formed of (m + 1) -order light in the diffraction grating, and the second small pattern has a second period equal to the first period along the predetermined direction of the spherical surface. periodically arranged in,
The first pattern includes a first first small pattern closest to the second pattern among the first small patterns,
The second pattern includes a first second small pattern closest to the first pattern among the second small patterns,
The first pattern and the second pattern are arranged along the predetermined direction of the spherical surface so that a periodic third pattern including the first small pattern and the second small pattern is formed. And
The diffractive optical element , wherein the first first small pattern and the first second small pattern are arranged at an interval equal to the first period and the second period . With a diffraction grating,
In the diffraction grating, when light having a single wavelength is diffracted by the diffraction grating and irradiated onto a curved surface, the image of the light forms a first pattern and a second pattern on the curved surface. The one curved surface is a spherical surface centered at a position where diffraction is generated in the diffraction grating,
The first pattern includes a first small pattern formed of m-order light (where m is a positive integer other than 0) in the diffraction grating, and the first small pattern is a predetermined direction of the spherical surface. Periodically arranged in a first period along
The second pattern includes a second small pattern formed of (m + 1) -order light in the diffraction grating, and the second small pattern has a second period equal to the first period along the predetermined direction of the spherical surface. periodically arranged in,
The first pattern includes a third small pattern located between the first small pattern and the second pattern,
The second pattern includes a fourth small pattern located between the second small pattern and the first pattern,
The first pattern and the second pattern are formed as a periodic third pattern including the first small pattern, the second small pattern, the third small pattern, and the fourth small pattern. Arranged along the predetermined direction of the spherical surface ,
The third small pattern and the fourth small pattern form a fifth small pattern,
The diffractive optics in which the first small pattern, the fifth small pattern, and the second small pattern are periodically arranged along the predetermined direction of the spherical surface with a period equal to the first period and the second period. element. The diffractive optical element according to claim 1 ,
When the first pattern and the second pattern are irradiated on one plane,
The first small patterns are arranged substantially periodically along a predetermined direction of the one plane,
The second small patterns are arranged substantially periodically along the predetermined direction of the one plane,
In the third pattern, the diffractive optical element in which the first small pattern and the second small pattern form a substantially periodic pattern arranged along the predetermined direction of the one plane. The diffractive optical element according to any one of claims 1 to 3 ,
A diffractive optical element in which m = 1. The diffractive optical element according to any one of claims 1 to 4 ,
The first small pattern and the second small pattern are diffractive optical elements that are one-dimensional patterns. The diffractive optical element according to any one of claims 1 to 4 ,
The diffractive optical element, wherein the first small pattern and the second small pattern are two-dimensional patterns. The diffractive optical element according to claim 2 ,
The first pattern is formed in a lattice shape,
The second pattern is formed in a lattice shape,
The third pattern is a diffractive optical element formed in a lattice shape. The diffractive optical element according to claim 1 ,
m = 1,
The 0th pattern, the 1st pattern, and the 2nd pattern formed by the 0th order light in the diffraction grating are periodic 1st patterns including the 0th pattern, the 1st small pattern, and the 2nd small pattern. A diffractive optical element arranged along the predetermined direction of the spherical surface so that four patterns are formed. Designing a diffraction grating; and
Forming the diffraction grating on the substrate based on the design of the diffraction grating in the step of designing the diffraction grating; and
Including
In the step of designing a diffraction grating, the diffraction grating has a first pattern on the curved surface when the light of a single wavelength is diffracted by the diffraction grating and irradiated on the curved surface. A second pattern, and the one curved surface is a spherical surface centered on a portion where diffraction is generated by the diffraction grating,
The first pattern includes a first small pattern formed of m-order light (where m is a positive integer other than 0) in the diffraction grating, and the first small pattern is a predetermined direction of the spherical surface. Periodically arranged in a first period along
The second pattern includes a second small pattern formed of (m + 1) -order light in the diffraction grating, and the second small pattern has a second period equal to the first period along the predetermined direction of the spherical surface. periodically arranged in,
The first pattern includes a first first small pattern closest to the second pattern among the first small patterns,
The second pattern includes a first second small pattern closest to the first pattern among the second small patterns,
The first pattern and the second pattern are arranged along the predetermined direction of the spherical surface so that a periodic third pattern including the first small pattern and the second small pattern is formed. And
The method of manufacturing a diffractive optical element , wherein the first first small pattern and the first second small pattern are arranged at an interval equal to the first period and the second period . Designing a diffraction grating; and
Forming the diffraction grating on the substrate based on the design of the diffraction grating in the step of designing the diffraction grating; and
Including
In the step of designing a diffraction grating, the diffraction grating has a first pattern on the curved surface when the light of a single wavelength is diffracted by the diffraction grating and irradiated on the curved surface. A second pattern, and the one curved surface is a spherical surface centered on a portion where diffraction is generated by the diffraction grating,
The first pattern includes a first small pattern formed of m-order light (where m is a positive integer other than 0) in the diffraction grating, and the first small pattern is a predetermined direction of the spherical surface. Periodically arranged in a first period along
The second pattern includes a second small pattern formed of (m + 1) -order light in the diffraction grating, and the second small pattern has a second period equal to the first period along the predetermined direction of the spherical surface. periodically arranged in,
The first pattern includes a third small pattern located between the first small pattern and the second pattern,
The second pattern includes a fourth small pattern located between the second small pattern and the first pattern,
The first pattern and the second pattern are formed as a periodic third pattern including the first small pattern, the second small pattern, the third small pattern, and the fourth small pattern. Arranged along the predetermined direction of the spherical surface ,
The third small pattern and the fourth small pattern form a fifth small pattern,
The diffractive optics in which the first small pattern, the fifth small pattern, and the second small pattern are periodically arranged along the predetermined direction of the spherical surface with a period equal to the first period and the second period. Device manufacturing method. A design unit for designing a diffraction grating for forming the first pattern;
A verification unit for verifying a position where the second pattern is formed by the diffraction grating designed by the design unit;
A correction unit that corrects the design of the diffraction grating designed by the design unit so that the position where the first pattern and the second pattern are formed is adjusted;
With
The first pattern and the second pattern are formed by an image of light having a single wavelength that is diffracted by the diffraction grating and applied to one curved surface, and the one curved surface is a portion where diffraction occurs in the diffraction grating. A spherical surface at the center,
The first pattern includes a first small pattern formed of m-order light (where m is a positive integer other than 0) in the diffraction grating, and the first small pattern is a predetermined direction of the spherical surface. Periodically arranged in a first period along
The second pattern includes a second small pattern formed of (m + 1) -order light in the diffraction grating, and the second small pattern has a second period equal to the first period along the predetermined direction of the spherical surface. periodically arranged in,
The first pattern includes a first first small pattern closest to the second pattern among the first small patterns,
The second pattern includes a first second small pattern closest to the first pattern among the second small patterns,
The correction unit moves the first pattern and the second pattern in the predetermined direction of the spherical surface so that a periodic third pattern including the first small pattern and the second small pattern is formed. the corrected design of the diffraction grating are arranged along,
The apparatus for designing a diffractive optical element , wherein the first first small pattern and the first second small pattern are arranged at an interval equal to the first period and the second period . A design unit for designing a diffraction grating for forming the first pattern;
A verification unit for verifying a position where the second pattern is formed by the diffraction grating designed by the design unit;
A correction unit that corrects the design of the diffraction grating designed by the design unit so that the position where the first pattern and the second pattern are formed is adjusted;
With
The first pattern and the second pattern are formed by an image of light having a single wavelength that is diffracted by the diffraction grating and applied to one curved surface, and the one curved surface is a portion where diffraction occurs in the diffraction grating. A spherical surface at the center,
The first pattern includes a first small pattern formed of m-order light (where m is a positive integer other than 0) in the diffraction grating, and the first small pattern is a predetermined direction of the spherical surface. Periodically arranged in a first period along
The second pattern includes a second small pattern formed of (m + 1) -order light in the diffraction grating, and the second small pattern has a second period equal to the first period along the predetermined direction of the spherical surface. periodically arranged in,
The first pattern includes a third small pattern located between the first small pattern and the second pattern,
The second pattern includes a fourth small pattern located between the second small pattern and the first pattern,
The correction unit includes the first pattern and the second pattern so that a periodic third pattern including the first small pattern, the second small pattern, the third small pattern, and the fourth small pattern is formed. Correcting the design of the diffraction grating by arranging a second pattern along the predetermined direction of the spherical surface ,
The third small pattern and the fourth small pattern form a fifth small pattern,
The diffractive optics in which the first small pattern, the fifth small pattern, and the second small pattern are periodically arranged along the predetermined direction of the spherical surface with a period equal to the first period and the second period. Device design equipment. A diffractive part constituted by the diffractive optical element according to any one of claims 1 to 8,
An irradiation unit for irradiating the diffractive optical element with light of a single wavelength;
A projection unit irradiated with a pattern of light diffracted by the diffraction grating of the diffractive optical element;
An imaging unit that continuously images temporally a pattern of light emitted from the diffractive optical element to the projection unit;
A storage unit for storing the light pattern captured by the imaging unit;
A determination unit that determines whether a light pattern at one time stored in the storage unit is different from a light pattern at another time stored in the storage unit;
Based on the determination result of the determination unit, a detection unit that detects the presence, shape, or position of an object irradiated with the light pattern diffracted by the diffraction grating of the diffractive optical element;
An object detection apparatus comprising: