WO2022168565A1 - Élément optique équipé d'un film antireflet et son procédé de fabrication - Google Patents

Élément optique équipé d'un film antireflet et son procédé de fabrication Download PDF

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Publication number
WO2022168565A1
WO2022168565A1 PCT/JP2022/001073 JP2022001073W WO2022168565A1 WO 2022168565 A1 WO2022168565 A1 WO 2022168565A1 JP 2022001073 W JP2022001073 W JP 2022001073W WO 2022168565 A1 WO2022168565 A1 WO 2022168565A1
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optical element
light
degrees
incident
angle
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PCT/JP2022/001073
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English (en)
Japanese (ja)
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俊之 児玉
健太 石井
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ナルックス株式会社
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    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B1/00—Optical elements characterised by the material of which they are made; Optical coatings for optical elements
    • G02B1/10—Optical coatings produced by application to, or surface treatment of, optical elements
    • G02B1/11—Anti-reflection coatings
    • G02B1/113—Anti-reflection coatings using inorganic layer materials only
    • G02B1/115—Multilayers
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B3/00—Simple or compound lenses

Definitions

  • an optical element having an antireflection film on its surface is used in order to reduce the proportion of light reflected on the surface of the optical element (for example, see Patent Document 1 and Patent Document 2).
  • some wide-angle projection optical systems project divergent light with a half-value of 85 degrees.
  • the maximum incident angles of the antireflection coatings described in Patent Documents 1 and 2 are 60 degrees and 45 degrees, respectively, which do not correspond to divergent light of 85 degrees at half maximum.
  • some wide-angle projection optics are designed so that the intensity of rays at the edges of the radiation beam is higher than the intensity of rays near the center of the radiation beam. In the optical element used in such a wide-angle projection optical system, the proportion of light reflected on the surface of the optical element becomes even greater.
  • optical elements used in wide-angle optical systems formed in such a way that the intensity of the rays at the periphery of the radiation beam is higher than the intensity of the rays near the center of the radiation beam, the optical element having a sufficiently high efficiency. and a method for producing the same.
  • the object of the present invention is to provide an optical element for use in wide-angle optics, which is formed so that the intensity of the rays at the edges of the radiation beam is higher than the intensity of the rays near the center of the radiation beam, and which has a sufficiently high efficiency. and a manufacturing method thereof.
  • An optical element is an optical element configured to diverge and emit light incident from one surface from the other surface and having an antireflection film on the other surface.
  • the optical element forms an angle of 60 degrees with the reference axis of divergence of the optical element when collimated light parallel to the reference axis of divergence of the optical element with a reference wavelength in the range of 400 nanometers to 1550 nanometers is incident from the one surface.
  • R( ⁇ ) is the reflectance when a ray of light is incident at an incident angle ⁇ (degrees), and the reflectance when a ray of light is incident on the surface of the optical element not provided with an antireflection coating at an incident angle ⁇ (degrees)
  • R 0 ( ⁇ ) is the reflectance, as well as , the value of K is is formed to have a minimum value in the range of .
  • the antireflection film of the optical element of this embodiment is formed so as to relatively increase the transmittance of light rays at large angles with respect to the reference axis of divergence.
  • the ratio to the luminous flux reaching the entrance surface of the optical element that is, the efficiency can be increased. Therefore, an optical element used in a wide-angle optical system formed such that the intensity of rays at the periphery of the emitted beam is higher than the intensity of rays near the center of the emitted beam, the optical element having sufficiently high efficiency. is obtained.
  • the optical element with a divergence function of the second embodiment of the first aspect of the present invention is an optical element with a microlens array on the one surface.
  • the antireflection film is composed of one layer of a material having a lower refractive index than the material of the optical element.
  • a method for manufacturing an optical element according to a second aspect of the present invention is an optical element configured to diverge and emit light incident from one surface from the other surface and having an antireflection film on the other surface. and the optical element serves as the reference axis when collimated light of a reference wavelength parallel to the reference axis of divergence of the optical element in the range of 400 nanometers to 1550 nanometers from the one surface is incident.
  • the intensity of the emitted ray at an angle D (degrees) in the range of 60 degrees to 85 degrees exhibits a maximum value, and the intensity of the emitted ray at the angle D is 1.3 times or more the intensity of the emitted ray in the direction of the reference axis.
  • the method includes the steps of designing an antireflection coating, determining the reflectance of an incident light ray of the reference wavelength of the antireflection coating at each angle of incidence, and causing light to enter an optical element provided with the antireflection coating. determining the ratio of the luminous flux passing through the exit surface of the antireflection coating to the luminous flux reaching the entrance surface of the optical element when the antireflection coating is not provided in consideration of the ratio. Design an optical element and an anti-reflection coating or anti-reflection coating.
  • the reflectance of the incident light beam of the reference wavelength of the antireflection film is obtained for each incident angle, and when light is incident on the optical element provided with the antireflection film,
  • the ratio of the luminous flux passing through the exit surface of the antireflection film to the luminous flux reaching the entrance surface of the optical element is determined, and in consideration of the ratio, an optical element not provided with an antireflection film, an antireflection film, or an antireflection film is obtained. Because the coating is designed, the ratio of the light flux passing through the exit surface of the antireflection coating to the light flux reaching the entrance surface of the optical element, that is, the efficiency can be increased.
  • optical elements used in wide-angle optical systems formed in such a way that the intensity of the rays at the periphery of the radiation beam is higher than the intensity of the rays near the center of the radiation beam, the optical element having a sufficiently high efficiency. is obtained.
  • the antireflection film is designed using the incident angle of the incident light beam of the reference wavelength that minimizes the reflectance of the antireflection film as a parameter. .
  • the antireflection film can be efficiently designed using the incident angle of the incident light beam of the reference wavelength that minimizes the reflectance of the antireflection film as a parameter.
  • the antireflection film of the optical element of this embodiment is formed so as to relatively increase the transmittance of light rays at large angles with respect to the reference axis of divergence.
  • the ratio to the luminous flux reaching the entrance surface of the optical element that is, the efficiency can be increased. Therefore, an optical element used in a wide-angle optical system formed such that the intensity of rays at the periphery of the emitted beam is higher than the intensity of rays near the center of the emitted beam, the optical element having sufficiently high efficiency. is obtained.
  • FIG. 2 shows an optical element of one embodiment of the invention
  • 4 is a flow chart for explaining a method of designing an optical element
  • FIG. 4 is a diagram illustrating an example of a target distribution of emitted light of an optical element
  • FIG. 3 is a flowchart for explaining step S1020 in FIG. 2
  • FIG. 4 is a diagram showing the relationship between the incident angle of light and the value of K for the antireflection films of Example 1 and Comparative Example 1.
  • FIG. 10 is a diagram showing the relationship between the incident angle of light and the reflectance for the antireflection films of Example 3 and Comparative Example 3;
  • FIG. 3 is a diagram showing the distribution of light just before reaching the incident surface of the antireflection film (distribution of light incident on the antireflection film);
  • FIG. 10 is a diagram showing the relationship between the incident angle of light and the value of K for the antireflection films of Example 4 and Comparative Example 4;
  • FIG. 10 is a diagram showing the relationship between the incident angle of light and the reflectance for the antireflection films of Example 4 and Comparative Example 4;
  • FIG. 3 is a diagram showing the distribution of light just before reaching the incident surface of the antireflection film (distribution of light incident on the antireflection film);
  • FIG. 10 is a diagram showing the relationship between the incident angle of light and the value of K for the antireflection coatings of Example 5 and Comparative Example 5;
  • FIG. 10 is a diagram showing the relationship between the incident angle of light and the reflectance for the antireflection films of Example 5 and Comparative Example 5;
  • the anti-reflection film of Example 5 when collimated light of the reference wavelength in the direction of the reference axis is incident, the anti-reflection film after passing through the microlens array surface for realizing the distribution of the radiated light of S1010.
  • FIG. 10 For the anti-reflection film of Example 5, when collimated light of the reference wavelength in the direction of the reference axis is incident, the anti-reflection film after passing through the microlens array surface for realizing the distribution of the radiated light of S1010.
  • FIG. 4 is a diagram showing the distribution of light just before reaching the incident surface (distribution of light incident on the antireflection film);
  • the luminous flux passing through the exit surface of the antireflection film and the reflection It is a figure which shows ratio with the luminous flux which reaches the entrance side of a prevention film.
  • Light flux passing through the exit surface of the antireflection film and optical It is a figure which shows the ratio with the luminous flux which reaches the entrance side of an element.
  • FIG. 10 is a flowchart for explaining a method of designing an antireflection coating while considering a third ratio when the shape of an optical element without an antireflection coating is fixed;
  • FIG. FIG. 4 is a diagram showing the arrangement of regular hexagonal bottom surfaces of the microlenses of the example.
  • FIG. 1 is a diagram showing an optical element 100 according to one embodiment of the present invention.
  • a microlens array 110 is provided on one side of the optical element 100 .
  • the microlens array 110 includes a plurality of identically shaped microlenses 115 .
  • the curved surfaces of the microlenses 115 are axially symmetrical about a central axis 120 passing through the vertex, and the central axes of the curved surfaces of the plurality of microlenses 115 are parallel to each other.
  • the microlens array 110 is configured to diverge a collimated light flux in the direction of the central axis 120 that is incident on the optical element 100 from the one side surface.
  • the optical element 100 includes, in addition to a microlens array, a CGH (Computer-Generated Hologram) or a single lens, e.g. may be a plano-concave lens.
  • the surface 130 on the other side of the optical element 100 may be a plane perpendicular to the central axis.
  • surface 130 is assumed to be a plane perpendicular to the central axis, but generally surface 130 may be a curved surface that is axisymmetric about another central axis parallel to central axis 120, for example.
  • Surface 130 is provided with an antireflection coating 140 . The function of the antireflection film 140 will be described later in detail.
  • the microlens array used for divergence is configured to diverge collimated light in the direction of the central axis of the curved surface of the microlens with reference to the central axis.
  • the single lens used for divergence is configured to diverge collimated light in the direction of its optical axis with respect to its optical axis.
  • the reference axis of divergence such as the central axis of the curved surface of the microlens and the optical axis of the single lens, is referred to herein as the reference axis of divergence, or simply the reference axis.
  • the reference axis of the optical element 100 shown in FIG. 1 is a straight line parallel to the central axis 120 and passing through the center of the surface on which the microlens array 110 is installed.
  • FIG. 2 is a flowchart for explaining the design method of the optical element 100.
  • step S1010 of FIG. 2 a target distribution of emitted light (emitted light) when collimated light in the direction of the reference axis is incident on the optical element 100 is determined.
  • FIG. 3 is a diagram showing an example of a target distribution of emitted light of the optical element 100.
  • FIG. The horizontal axis of FIG. 3 is the angle formed by the ray of radiation with respect to the reference axis. The units for angles are degrees.
  • the vertical axis in FIG. 3 is the intensity of light. The light intensity is normalized so that the value integrated over the angle from 0 to 90 degrees becomes 1.
  • the intensity of the ray at 85 degrees to the reference axis is maximum.
  • the angle at which the intensity exhibits the maximum value is denoted by D.
  • the intensity at angle D is approximately 2.0 times the intensity at 0 degrees.
  • step S1020 of FIG. 2 an antireflection film is designed.
  • the present invention designs the antireflection coating formed on the other surface of the optical element in consideration of the target distribution of the emitted light as shown in FIG.
  • FIG. 4 is a flow chart for explaining step S1020 in FIG.
  • step S2010 of FIG. 4 the angle D of the optical element that realizes the desired radiated light intensity distribution is determined with respect to the reference axis at which the radiated light intensity exhibits the maximum value.
  • an antireflection film is formed on the surface of the substrate made of the same material as the optical element, and the reflectance when a light beam is incident at an incident angle ⁇ is R( ⁇ ).
  • R 0 ( ⁇ ) be the reflectance when a ray of light is incident on the surface of a base material that is not exposed to light at an angle of incidence ⁇ .
  • K the value of K is The antireflection coating is designed to have a minimum value in the range of . Specifically, we designed an antireflection coating that is formed on the surface of a substrate made of the same material as the optical element and that minimizes the reflectance when a light beam is incident at a certain angle of incidence ⁇ .
  • the value of K for various values of .theta. is obtained for the antireflection film, and the value of .theta. at which the value of K exhibits the minimum value is obtained. If necessary, the process of designing the anti-reflection film by changing the incident angle ⁇ that minimizes the reflectance is repeated. In this way, various antireflection coatings with different angles at which K exhibits a minimum value are designed, and the value of K is An antireflection coating can be designed to have a minimum value in the range of .
  • the solid line in FIG. 5A shows an example of K with respect to the incident angle of light (Example 1 described later).
  • the horizontal axis of FIG. 5A indicates the incident angle of the light.
  • the units for angles are degrees.
  • Figure 5A shows the value of K; In the case of the solid line in FIG. 5A, the value of K shows a minimum value at an incident angle of 73 degrees.
  • step S1030 of FIG. 2 the reflectance of the antireflection film is obtained for each incident angle of light.
  • the solid line in FIG. 5B shows an example of the reflectance of the antireflection film with respect to the incident angle of light (Example 1 described later).
  • the horizontal axis of FIG. 5 indicates the incident angle of light.
  • the units for angles are degrees.
  • the vertical axis of FIG. 5B indicates the reflectance of the antireflection film.
  • the unit of reflectance is percent.
  • step S1040 of FIG. 2 when collimated light in the direction of the reference axis is incident on the optical element, the distribution of light reaching the entrance surface of the antireflection film that realizes the distribution of emitted light in S1010 is obtained.
  • the distribution of light reaching the entry surface of the anti-reflection coating which achieves the distribution of emitted light in S1010, is a function of the relative ray intensity at an angle shown in FIG. It can be obtained by dividing the value by the transmittance and taking the relative light intensity at that angle.
  • the transmittance (percentage) of the antireflection film is obtained by subtracting the reflectance (percentage) obtained in step S1030 from 100.
  • the solid line in FIG. 6 is an example of the distribution of light reaching the entrance surface of the anti-reflection coating that achieves the distribution of emitted light in S1010 when collimated light in the direction of the reference axis is incident on the optical element (later An illustrative embodiment 1) is shown.
  • the distribution of light reaching the entry surface of the antireflection coating is the distribution of light passing through the exit surface of the optical element without the antireflection coating. Therefore, when collimated light in the direction of the reference axis is made incident on an optical element having no antireflection film, the distribution of emitted light in S1010 is achieved if the distribution indicated by the solid line in FIG. 6 is obtained.
  • FIG. 6 is the angle formed by the ray of emitted light with respect to the reference axis.
  • the units for angles are degrees.
  • the vertical axis in FIG. 6 is the intensity of light.
  • the light intensity is normalized so that the value integrated over the angle from 0 to 90 degrees becomes 1.
  • step S1050 of FIG. 2 an optical element not provided with an antireflection film that realizes the distribution of emitted light obtained in step S1040 is designed. Specifically, by changing the shape of the microlens, it is possible to change the distribution of radiated light when collimated light in the direction of the reference axis is incident on the optical element.
  • step S1060 in FIG. 2 the ratio of the luminous flux passing through the exit surface of the optical element provided with the antireflection coating to the luminous flux reaching the entrance surface when collimated light in the direction of the reference axis is made incident on the optical element. Determine if the light distribution and geometry of the optical element without anti-reflection coating is satisfactory. If it is satisfactory, the process ends. If not satisfactory, return to step S1020.
  • the vertex of the lens is the origin
  • the x-axis and y-axis are defined in a plane that includes the origin and is parallel to the bottom surface
  • the z-axis that is orthogonal to the x-axis and y-axis is defined.
  • the z-axis direction is the traveling direction of light traveling in the z-axis direction from the light source.
  • the curved surface of the microlens and the exit surface of the optical element can be expressed by the following equations.
  • c represents the curvature at the vertex of the curved surface and is the reciprocal of the curvature radius R.
  • r represents a straight line in the z-axis direction passing through a point on the curved surface and a vertex of the curved surface, that is, the distance from the reference axis.
  • k is a conic coefficient and Ai is an aspheric coefficient of order i.
  • each microlens is a regular hexagon
  • the microlens array is configured by arranging microlenses with regular hexagonal bases on a plane without gaps.
  • FIG. 18 is a diagram showing the arrangement of regular hexagonal bottom surfaces of the microlenses of the example.
  • the x-axis distance dx between the centers of adjacent regular hexagons is 0.225 millimeters
  • the y-axis distance dy between the centers of adjacent regular hexagons is 0.260 millimeters
  • the length P of the diagonal line passing through the center of the regular hexagon is 0.3 millimeters.
  • the thickness of the optical element in the z-axis direction that is, the distance in the z-axis direction from the vertex of the microlens to the exit surface is 1 millimeter.
  • the material of the optical elements is polycarbonate, which has a refractive index of 1.61 for light with a reference wavelength of 850 nanometers.
  • the optical properties of the optical element and the anti-reflection coating described in this specification are determined by simulation of light with a wavelength of 850 nanometers using optical software such as Zemax and Optilayer.
  • the following example is an optical element configured to achieve the target distribution of emitted light shown in FIG.
  • Example 1 The antireflection films of Example 1 and Comparative Example 1 are two-layer antireflection films.
  • the first layer from the substrate side of the same material as the optical element is a high refractive material layer made of titanium dioxide
  • the second layer is a low refractive material layer made of silicon dioxide.
  • the outermost second layer is a low refractive material layer.
  • the refractive index of the high refractive material layer made of titanium dioxide is 2.3740 and the refractive index of the low refractive material layer made of silicon dioxide is 1.4617 for light with a reference wavelength of 850 nanometers.
  • Table 1 shows the film thickness of each layer in Example 1 and Comparative Example 1.
  • the unit of film thickness is nanometers.
  • the antireflection film of Example 1 is designed so that the value of K shows a minimum value at an incident angle of 73 degrees.
  • the anti-reflection film of Comparative Example 1 is designed to minimize the reflectance of the reference wavelength light at an incident angle of 0 degree.
  • FIG. 6 shows microlenses for realizing the target distribution of emitted light shown in FIG.
  • FIG. 4 is a diagram showing the distribution of light (distribution of light incident on the antireflection film) immediately before reaching the incident surface of the antireflection film after passing through the array surface;
  • the horizontal axis of FIG. 6 is the angle formed by the ray of emitted light with respect to the reference axis. The units for angles are degrees.
  • the vertical axis in FIG. 6 is the intensity of light. The light intensity is normalized so that the value integrated over the angle from 0 to 90 degrees becomes 1.
  • the solid line indicates Example 1
  • the dashed line indicates Comparative Example 1. According to FIG.
  • Table 2 is a table showing numerical data of microlenses that realize the distribution of radiated light in Example 1 and Comparative Example 1 shown in FIG. The above numerical data are the coefficients and constants of equation (1).
  • Example 2 The antireflection films of Example 2 and Comparative Example 2 are three-layered antireflection films. From the substrate side of the same material as the optical element, the first layer is a low refractive material layer made of silicon dioxide, the second layer is a high refractive material layer made of titanium dioxide, and the third layer is a low refractive material layer made of silicon dioxide. . The outermost third layer is a low refractive material layer.
  • Table 3 shows the film thickness of each layer in Example 2 and Comparative Example 2.
  • the unit of film thickness is nanometers.
  • FIG. 7A is a diagram showing the relationship between the incident angle of light and the value of K for the antireflection films of Example 2 and Comparative Example 2.
  • FIG. The horizontal axis of FIG. 7A indicates the incident angle of the light. The units for angles are degrees.
  • the vertical axis in FIG. 7A indicates the K value.
  • FIG. 8 shows microlenses for realizing the target distribution of emitted light shown in FIG.
  • FIG. 4 is a diagram showing the distribution of light (distribution of light incident on the antireflection film) immediately before reaching the incident surface of the antireflection film after passing through the array surface;
  • the horizontal axis of FIG. 8 is the angle formed by the ray of emitted light with respect to the reference axis. The units for angles are degrees.
  • the vertical axis in FIG. 8 is the intensity of light.
  • the light intensity is normalized so that the value integrated over the angle from 0 to 90 degrees becomes 1.
  • the solid line indicates Example 2
  • the dashed line indicates Comparative Example 2.
  • the ratio of the intensity of the light beam at an angle of 85 degrees with the reference axis in Comparative Example 2 to the intensity of the light beam in the direction of the reference axis is about 1.47 of the ratio in Example 2. Double.
  • Example 3 The antireflection films of Example 3 and Comparative Example 3 are four-layer antireflection films. From the substrate side of the same material as the optical element, the first layer is a high refractive material layer made of titanium dioxide, the second layer is a low refractive material layer made of silicon dioxide, the third layer is a high refractive material layer made of titanium dioxide, and the third layer is a high refractive material layer made of titanium dioxide. Layer 4 is a low refractive material layer made of silicon dioxide. The outermost fourth layer is a low refractive material layer.
  • Table 4 shows the film thickness of each layer in Example 3 and Comparative Example 3.
  • the unit of film thickness is nanometers.
  • the antireflection film of Example 3 is designed so that the value of K shows a minimum value at an incident angle of 76 degrees.
  • the anti-reflection coating of Comparative Example 3 is designed to minimize the reflectance of the reference wavelength light beam with an incident angle of 0 degrees.
  • FIG. 9A is a diagram showing the relationship between the incident angle of light and the value of K for the antireflection films of Example 3 and Comparative Example 3.
  • FIG. The horizontal axis of FIG. 9A indicates the incident angle of light. The units for angles are degrees.
  • the vertical axis in FIG. 9A indicates the K value.
  • FIG. 9B is a diagram showing the relationship between the incident angle of light rays and the reflectance for the antireflection films of Example 3 and Comparative Example 3.
  • FIG. The horizontal axis of FIG. 9B indicates the incident angle of the light. The units for angles are degrees.
  • the vertical axis of FIG. 9B indicates the reflectance of the antireflection film. The unit of reflectance is percent.
  • the solid line indicates Example 3, and the dashed line indicates Comparative Example 3.
  • the reflectance is minimized at an incident angle of 40 degrees.
  • Comparative Example 3 the reflectance becomes minimum at an incident angle of 0 degree.
  • FIG. 10 shows microlenses for realizing the target distribution of emitted light shown in FIG.
  • FIG. 4 is a diagram showing the distribution of light (distribution of light incident on the antireflection film) immediately before reaching the incident surface of the antireflection film after passing through the array surface;
  • the horizontal axis of FIG. 10 is the angle formed by the ray of emitted light with respect to the reference axis. The units for angles are degrees.
  • the vertical axis in FIG. 10 is the intensity of light. The light intensity is normalized so that the value integrated over the angle from 0 to 90 degrees becomes 1.
  • the solid line indicates Example 3, and the dashed line indicates Comparative Example 3. According to FIG.
  • the ratio of the intensity of the light ray forming an angle of 85 degrees with the reference axis in the case of Comparative Example 3 to the intensity of the light ray in the direction of the reference axis is about 1.46 of the ratio in the case of Example 3. Double.
  • Example 4 The antireflection films of Example 4 and Comparative Example 4 are five-layer antireflection films. From the substrate side of the same material as the optical element, the first layer is a low refractive material layer made of silicon dioxide, the second layer is a high refractive material layer made of titanium dioxide, the third layer is a low refractive material layer made of silicon dioxide, and the third layer is a low refractive material layer made of silicon dioxide. The fourth layer is a high refractive material layer made of titanium dioxide, and the fifth layer is a low refractive material layer made of silicon dioxide. The outermost fifth layer is a low refractive material layer.
  • Table 5 is a table showing the film thickness of each layer in Example 4 and Comparative Example 4.
  • the unit of film thickness is nanometers.
  • FIG. 11A is a diagram showing the relationship between the incident angle of light and the value of K for the antireflection films of Example 4 and Comparative Example 4.
  • FIG. The horizontal axis of FIG. 11A indicates the incident angle of light. The units for angles are degrees.
  • the vertical axis in FIG. 11A indicates the K value.
  • FIG. 12 shows microlenses for realizing the target distribution of emitted light shown in FIG.
  • FIG. 4 is a diagram showing the distribution of light (distribution of light incident on the antireflection film) immediately before reaching the incident surface of the antireflection film after passing through the array surface;
  • the horizontal axis of FIG. 12 is the angle formed by the ray of emitted light with respect to the reference axis. The units for angles are degrees.
  • the vertical axis in FIG. 12 is the intensity of light. The light intensity is normalized so that the value integrated over the angle from 0 to 90 degrees becomes 1. According to FIG.
  • the ratio of the intensity of the light ray forming an angle of 85 degrees with the reference axis in the case of Comparative Example 4 to the intensity of the light ray in the direction of the reference axis is about 1.5 of the ratio in the case of Example 4. Double.
  • Example 5 The antireflection coating of Example 5 is a single layer antireflection coating.
  • a single layer of silicon dioxide is formed on the planar surface of a substrate of the same material as the optical element.
  • the refractive index of a single layer is 1.2316.
  • the substrate functions as a high refractive index layer
  • the single layer functions as a low refractive index layer
  • Table 6 is a table showing the film thickness of the single layer of Example 5 and Comparative Example 5.
  • the unit of film thickness is nanometers.
  • the antireflection film of Example 5 is designed so that the value of K shows a minimum value at an incident angle of 65 degrees.
  • the anti-reflection film of Comparative Example 5 is designed to minimize the reflectance of the reference wavelength light at an incident angle of 0 degrees.
  • FIG. 13A is a diagram showing the relationship between the incident angle of light and the value of K for the antireflection films of Example 5 and Comparative Example 5.
  • FIG. The horizontal axis of FIG. 13A indicates the incident angle of the light. The units for angles are degrees.
  • the vertical axis in FIG. 13A indicates the K value.
  • FIG. 13B is a diagram showing the relationship between the incident angle of light rays and the reflectance for the antireflection films of Example 5 and Comparative Example 5.
  • FIG. The horizontal axis of FIG. 13B indicates the incident angle of the light. The units for angles are degrees.
  • the vertical axis of FIG. 13B indicates the refractive index of the antireflection film. The unit of refractive index is percent. In Example 5, the reflectance is minimized at an incident angle of 60 degrees.
  • FIG. 14 shows microlenses for realizing the target distribution of emitted light shown in FIG.
  • FIG. 4 is a diagram showing the distribution of light (distribution of light incident on the antireflection film) immediately before reaching the incident surface of the antireflection film after passing through the array surface;
  • the horizontal axis of FIG. 14 is the angle formed by the ray of emitted light and the reference axis. The units for angles are degrees.
  • the vertical axis in FIG. 14 is the intensity of light. The light intensity is normalized so that the value integrated over the angle from 0 to 90 degrees becomes 1. According to FIG.
  • the ratio of the intensity of the ray forming an angle of 85 degrees with the reference axis in the case of Comparative Example 5 to the intensity of the ray in the direction of the reference axis is about 1.3 of the ratio in the case of Example 5. Double.
  • the value of K shows a minimum value at incident angles ⁇ of 73 degrees, 76 degrees, 76 degrees, 77 degrees and 65 degrees, respectively. Since D is 85 degrees, the value of K is shows the minimum value in the range of .
  • the antireflection film of the optical element of Example 1-5 shows the minimum reflectance at incident angles ⁇ of 60 degrees, 55 degrees, 40 degrees, 40 degrees and 60 degrees, respectively.
  • FIG. 15 shows the light passing through the exit surface of the antireflection film when collimated light in the direction of the reference axis is incident on the optical element provided with the antireflection film in each of Example 1-5 and Comparative Example 1-4.
  • FIG. 3 is a diagram showing a ratio of a luminous flux that passes through and a luminous flux that reaches an entrance surface of an antireflection film. "Without film” in FIG. 15 indicates the luminous flux that passes through and reaches the exit surface of an optical element that does not have an antireflection coating designed to realize the luminous intensity distribution of the emitted light shown in FIG. shows the ratio of
  • the ratio of the luminous flux passing through the exit surface of the antireflection coating in Example 1-5 to the luminous flux reaching the entrance surface of the antireflection coating is It is about 5-11 percent higher compared to the ratio of the luminous flux passing through to the luminous flux reaching the exit surface. Also, the ratio of the luminous flux passing through the exit side of the antireflection coating of Examples 1-4 to the luminous flux reaching the entrance side of the antireflection coating is about 0.5-4% higher than the above ratio of the comparative example. .
  • FIG. 16 shows the light passing through the exit surface of the antireflection film when collimated light in the direction of the reference axis is incident on the optical element provided with the antireflection film in each of Example 1-5 and Comparative Example 1-4.
  • FIG. 4 is a diagram showing the ratio of the luminous flux that passes through and the luminous flux that reaches the entrance surface of the optical element.
  • "Without film” in FIG. 16 is obtained when collimated light in the direction of the reference axis is incident on an optical element that does not have an antireflection film designed to realize the luminous intensity distribution of emitted light shown in FIG. , denotes the ratio of the luminous flux passing through the exit side of the optical element to the luminous flux reaching the entrance side of the optical element.
  • the ratio of the luminous flux passing through the exit surface of the antireflection coating in Example 1-5 to the luminous flux reaching the entrance surface of the optical element is about 3.5-8 percent higher than the ratio of the luminous flux passing through and reaching the entrance side of the optic. Also, the ratio of the luminous flux passing through the exit surface of the antireflection coating of Examples 1-4 to the luminous flux reaching the entrance surface of the optical element is about 1.5-3% higher than the above ratio of the comparative example.
  • the luminous flux passing through the exit surface of the antireflection film and the luminous flux reaching the entrance surface of the optical element the luminous flux passing through the exit surface of the antireflection film and the antireflection
  • the luminous flux passing through the exit surface of the antireflection film and the antireflection In addition to increasing the ratio of the luminous flux reaching the entrance side of the film (the first ratio), the luminous flux passing through the exit side of an optical element not provided with an antireflection coating and the luminous flux reaching the entrance side of the optical element It is considered that the increase in the ratio of (second ratio) also contributes. The reason is as follows. Collimation parallel to the reference axis is provided in the optical element to achieve the desired distribution of emitted light as shown in FIG.
  • the second ratio is increased, for example by reducing the curvature of the microlenses, compared to the prior art as described in connection with the first embodiment.
  • Another embodiment example has been used to describe a method of designing an optical element without an anti-reflection coating and an anti-reflection coating from a target distribution of radiation while considering a third ratio.
  • the present invention can also be applied to a method of designing an antireflection coating while considering the third ratio when the shape of an optical element without an antireflection coating is fixed.
  • FIG. 17 is a flowchart for explaining a method of designing an antireflection film while considering the third ratio when the shape of an optical element not provided with an antireflection film is fixed.
  • step S3010 of FIG. 17 an antireflection film is designed.
  • the design of the antireflection film is carried out according to the procedure shown in the flow chart of FIG.
  • step S3020 of FIG. 17 it is determined whether or not the third ratio and the distribution of emitted light are satisfactory when collimated light in the direction of the reference axis is incident on the optical element. If it is satisfactory, the process ends. If not satisfactory, return to step S3010.
  • the light incident on the optical element is collimated light parallel to the reference axis of the microlens, but the present invention can be applied even if the light incident on the optical element is divergent light.
  • the other surface of the optical element on which the antireflection film is formed is a plane perpendicular to the reference axis.
  • the present invention can be applied even to a spherical surface whose absolute value is 100 times or more the radius of curvature of the microlens.
  • the reference wavelength is in the range of 400 nanometers to 1550 nanometers, the absorption of light by the materials of the optical element and the antireflection film shown in the above examples can be ignored.
  • a sufficiently efficient optical element is obtained by the procedure shown in FIG. 2 or FIG. 17 using optical elements and antireflection coatings.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Chemical & Material Sciences (AREA)
  • Inorganic Chemistry (AREA)
  • Surface Treatment Of Optical Elements (AREA)

Abstract

Un élément optique selon la présente invention est configuré de telle sorte que la lumière incidente à partir de la surface sur un côté de celui-ci est rayonnée et émise à partir de la surface de l'autre côté, et l'élément optique est équipé d'un film antireflet sur la surface de l'autre côté. Cet élément optique est formé de telle sorte que, lorsqu'une lumière collimatée parallèle à l'axe de référence du rayonnement de l'élément optique et ayant une longueur d'onde de référence dans une plage de 400 à 1550 nm est incidente à partir de la surface sur un côté, l'intensité d'un rayon lumineux émis exprime la valeur maximale de celui-ci à un angle D (degrés) dans une plage où l'angle formé avec l'axe de référence est de 60 à 85 degrés, et l'intensité du rayon lumineux émis à l'angle D est d'au moins 1,3 fois l'intensité du rayon lumineux émis dans la direction de l'axe de référence. Le film antireflet est formé de telle sorte que la valeur de K atteint la valeur minimale de celui-ci à un angle dans la plage allant de a (D-20) degrés à D degrés si la réflectivité lorsque le rayon lumineux est incident à un angle incident θ (degrés) est défini comme R(θ), et la réflectivité lorsque le rayon lumineux est incident à un angle incident θ (degrés) sur la surface de l'élément optique où le film antireflet n'est pas fourni est défini comme étant R0(θ). (AAA)
PCT/JP2022/001073 2021-02-02 2022-01-14 Élément optique équipé d'un film antireflet et son procédé de fabrication WO2022168565A1 (fr)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2023210100A1 (fr) * 2022-04-28 2023-11-02 ナルックス株式会社 Élément optique pourvu d'un film antireflet

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2005173029A (ja) * 2003-12-09 2005-06-30 Pentax Corp 反射防止膜を有する光学素子及び反射防止膜の設計方法
WO2019230758A1 (fr) * 2018-05-29 2019-12-05 株式会社クラレ Film à motif fin et dispositif d'affichage tête haute
JP2020067664A (ja) * 2018-10-26 2020-04-30 ヴァイアヴィ・ソリューションズ・インコーポレイテッドＶｉａｖｉ Ｓｏｌｕｔｉｏｎｓ Ｉｎｃ． 光学素子及び光学系
JP2021002632A (ja) * 2019-06-25 2021-01-07 豊田合成株式会社 発光装置及びその製造方法

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2005173029A (ja) * 2003-12-09 2005-06-30 Pentax Corp 反射防止膜を有する光学素子及び反射防止膜の設計方法
WO2019230758A1 (fr) * 2018-05-29 2019-12-05 株式会社クラレ Film à motif fin et dispositif d'affichage tête haute
JP2020067664A (ja) * 2018-10-26 2020-04-30 ヴァイアヴィ・ソリューションズ・インコーポレイテッドＶｉａｖｉ Ｓｏｌｕｔｉｏｎｓ Ｉｎｃ． 光学素子及び光学系
JP2021002632A (ja) * 2019-06-25 2021-01-07 豊田合成株式会社 発光装置及びその製造方法

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2023210100A1 (fr) * 2022-04-28 2023-11-02 ナルックス株式会社 Élément optique pourvu d'un film antireflet

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