Laminated window for an infrared detection system

Abstract

Windows for detection systems including an asymmetric laminate structure are disclosed. The asymmetric laminate structure comprises a first glass ply, a second glass ply, and an intermediate layer that bonds the first glass ply to the second glass ply. The first glass ply is at least twice as thick as the second glass ply and is less reinforced than the second glass ply such that the first glass ply has a central tension that is less than the central tension of the central region of the second glass ply. The intermediate layer has an average light transmittance of 98% or more through a 50 nm wavelength range of interest included in the wavelength range from 800 nm to 1800 nm.

Description

Priority

[0001] This application claims the benefit of priority under 35 U.S.C. § 119 to U.S. Provisional Patent Application No. 63 / 349,764, filed on June 7, 2022, the content of which is relied upon and incorporated herein by reference in its entirety.

Technical Field

[0002] The present disclosure relates to a laminated window for an infrared detection system.

Background Art

[0003] Optical sensing and ranging (“LIDAR”) systems include an electromagnetic radiation emitter and a sensor. The electromagnetic radiation emitter emits electromagnetic radiation, which may be reflected by an object and detected by the sensor. The electromagnetic radiation may be pulsed over a radial range or distributed in some other pattern over the field of view to detect objects. Information about the object can be interpreted from the nature of the detected reflected electromagnetic radiation. The distance of the object from the electromagnetic radiation can be determined from the time of flight from the emission of the electromagnetic radiation to the detection of the reflected electromagnetic radiation. If the object is moving, the path and speed of the object can be determined from the shift in the emission position of the emitted electromagnetic radiation reflected and detected as a function of time, as well as from Doppler frequency measurements.

[0004] LIDAR systems in automobiles, as well as other infrared detection systems in exposed environments such as aerospace applications and home security applications, need to be protected from the environment and various damage sources, for example, by a cover lens or a cover glass window. Vehicles are another potential application for LIDAR systems, and the LIDAR system provides a spatial mapping ability that enables assisted, semi-autonomous, or fully autonomous driving. In such applications, electromagnetic radiation emitters and sensors are mounted on the roof of the vehicle or on the lower front part of the vehicle. Electromagnetic radiation emitters that emit electromagnetic radiation having a wavelength outside the visible light range, such as 905 nm or 1550 nm, are being considered for automotive LIDAR applications. In order to protect the electromagnetic radiation emitter and the sensor from colliding with stones and other objects, a window is disposed between the electromagnetic radiation emitter and the sensor and the external environment in the line of sight of the electromagnetic radiation emitter and the sensor. In other applications of LIDAR systems such as aerospace applications and home security applications, a window is similarly disposed between the electromagnetic radiation emitter / sensor and the external environment.

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, stones and other objects that collide with the window scratch the window or cause other types of damage, and the window scatters the radiated and reflected electromagnetic radiation, thus posing a problem in that the effectiveness of the LIDAR system is impaired.

Means for Solving the Problems

[0006] In the present disclosure, the problem is solved by a window having an asymmetric laminate structure that also provides appropriate optical performance in a wavelength range of interest related to a detection system. The window includes a first glass ply forming an outer surface of the window facing the external environment, a second glass ply forming an inner surface facing components of the detection system (e.g., emitters and sensors), and an intermediate layer bonding the first glass ply to the second glass ply. The first glass ply is generally less strengthened (e.g., thermally, mechanically, chemically) than the second glass ply, and thus the first glass ply generally has a central tension smaller than the central tension of the second glass ply so as to resist crack propagation. The first glass ply has a first thickness greater than a second thickness with respect to the second glass ply to improve impact resistance performance. The second glass ply can be chemically strengthened to help maintain hermeticity when a flaw (e.g., crack, hole, gap) that spreads to the first glass ply due to impact occurs. The intermediate layer is selected to bond the first glass ply to the second glass ply with sufficient durability and also provide a relatively high light transmittance in a wavelength range of interest related to the detection system. In an embodiment, the wavelength range of interest includes a 50 nm wavelength range of interest included in the wavelength range from 800 nm to 1800 nm. The laminate described herein provides improved impact performance over certain existing monolithic window structures and also has light transmission characteristics essential for sensor applications.

[0007] Aspect (1) of the present disclosure relates to a window for a detection system, comprising: a first glass ply having a first major surface, a second major surface opposite the first major surface, and a first thickness extending between the first major surface and the second major surface; a second glass ply having a third major surface, a fourth major surface opposite the third major surface, and a second thickness extending between the third major surface and the fourth major surface; an intermediate layer disposed between the first glass ply and the second glass ply, bonding the second major surface to the third major surface; and one or more laminated films disposed on at least one of the first major surface and the fourth major surface, each of the one or more laminated films comprising alternating layers of one or more high refractive index materials and one or more low refractive index materials. The intermediate layer, alone, has an average transmittance of greater than 98% over a 50 nm wavelength range of interest for light normally incident on the fourth major surface or the first major surface, the 50 nm wavelength range of interest being included in the wavelength range from 800 nm to 1800 nm. The alternating layers of the one or more laminated films are configured to exhibit an average transmittance of 95% or more over a 50 nm wavelength range of interest for light normally incident on the first major surface or the fourth major surface of the window, and the alternating layers of the one or more laminated films are configured to exhibit an average reflectance of 5% or less over a 50 nm wavelength range of interest for light normally incident on the first major surface or the fourth major surface of the window. The first thickness is at least twice as thick as the second thickness, and the second glass ply is reinforced to a greater extent than the first glass ply such that the second glass ply exhibits a central tension greater than the central tension of the central region of the first glass ply.

[0008] Aspect (2) of the present disclosure relates to a window according to aspect (1), wherein the first glass ply is not reinforced.

[0009] Aspect (3) of the present disclosure relates to a window according to any of the preceding aspects, wherein the first thickness is 2.0 mm or more and 8.0 mm or less, and the second thickness is 0.1 mm or more and 1.2 mm or less.

[0010] Aspect (4) of the present disclosure relates to a window according to any of the previous aspects, in which both the first glass ply and the second glass ply are formed from aluminosilicate glass.

[0011] Aspect (5) of the present disclosure relates to a window according to any of aspects (1) to (3), in which the first glass ply is formed from a glass that exhibits anomalous fracture behavior when a Vickers indenter test is performed.

[0012] Aspect (6) of the present disclosure relates to a window according to aspect (5), in which the first glass ply is made from a borosilicate glass composition.

[0013] Aspect (7) of the present disclosure relates to a window according to aspect (6), in which, with respect to the constituent oxides, the borosilicate glass composition contains SiO2, B2O3, Al2O3, one or more alkali metal oxides, and one or more divalent cation oxides selected from the group consisting of MgO, CaO, SrO, BaO, and ZnO, 11 mol% or more and 16 mol% or less of B2O3, 2 mol% or more and 6 mol% or less of Al2O3, and a total of 7.0 mol% or more of Na2O, K2O, MgO, and CaO, and the concentrations of the oxide-based molar percentages of SiO2, B2O3, one or more alkali metal oxides, Al2O3, and one or more alkaline earth metal oxides satisfy the relational expressions: (R2O + R’O) ≧ Al2O3, 0.80 < (1 - [(2R2O + 2R’O) / (SiO2 + 2Al2O3 + 2B2O3)]) < 0.93, where R2O is the sum of the concentrations of one or more alkali metal oxides and R’O is the sum of the concentrations of one or more alkaline earth metal oxides.

[0014] Aspect (8) of the present disclosure relates to a window according to any of the previous aspects, in which the first thickness is at least three times thicker than the second thickness.

[0015] Aspect (9) of the present disclosure relates to a window according to any of the previous aspects, in which the second glass ply is chemically strengthened so that the second glass ply has a surface compressive stress on the fourth major surface of 250 MPa or more and 900 MPa or less.

[0016] Aspect (10) of the present disclosure relates to a window according to aspect (9) in which when a first glass ply collides with a 1 g ball bearing moving at 160.93 km / h, no crack that penetrates all of the second thickness is formed.

[0017] Aspect (11) of the present disclosure relates to a window according to any of the preceding aspects, wherein the intermediate layer is made of an optically clear adhesive or an ultraviolet curable acrylic resin.

[0018] Aspect (12) of the present disclosure relates to a window according to aspect (11), wherein the intermediate layer has a third thickness of 0.05 mm or more and 1.0 mm or less.

[0019] Aspect (13) of the present disclosure relates to a window according to any of aspects (1)-(12), wherein the wavelength range of interest of 50 nm is centered at a wavelength between 900 nm and 950 nm.

[0020] Aspect (14) of the present disclosure relates to a window according to any of aspects (1)-(12), wherein the wavelength range of interest of 50 nm is centered at a wavelength between 1525 nm and 1575 nm.

[0021] Aspect (15) of the present disclosure relates to a window according to any of the preceding aspects, wherein the one or more layer films include a first layer film disposed on a first major surface, and the window has a maximum hardness of at least 8 GPa as measured by a Berkovich indenter hardness test on the first layer film.

[0022] Aspect (16) of the present disclosure relates to a window according to any of the preceding aspects, wherein the one or more layer films include a second layer film disposed on a fourth major surface, and the quantity, thickness, number, and material of the alternating layers of the first and second layer films are such that the window has an average reflectance calculated for a wavelength range of interest of 50 nm between 1400 nm and 1600 nm of less than 0.5% for light incident on the first and second major surfaces at an angle of 15° or less; a CIELAB L of 45 or less for an angle of incidence of 60° or less on the first layer film *Value; and CIELAB a that is -6.0 or more and 6.0 or less when viewed from the side of the first laminated film * and b * relates to a window according to aspect (15) configured to have such values.

[0023] Aspect (17) of the present disclosure is such that one of the alternating layers of the first laminated film furthest from the first major surface forms the end face material of the window, the end face material of the window is made of a low refractive index material, the first laminated film is formed from one of one or more high refractive index materials, and includes a scratch-resistant layer having a thickness of 1500 nm or more and 5000 nm or less, and relates to a window according to aspect (16).

[0024] Aspect (18) of the present disclosure is such that the scratch-resistant layer is separated from the end face by a plurality of layers within the alternating layers of one or more low refractive index materials and one or more high refractive index materials of the first laminated film, and the scratch-resistant layer is separated from the end face by at least 1000 nm, and relates to a window according to aspect (17).

[0025] Aspect (19) of the present disclosure is such that one or more laminated films include a second laminated film disposed on the fourth major surface, and the number, thickness, and material of the alternating layers of the first and second laminated films are such that the window has an average transmittance calculated over a 50 nm wavelength range of interest of more than 90% for light incident on the first and second major surfaces at an incident angle of 15° or less; an average reflectance calculated over a 50 nm wavelength range of interest of less than 0.5% for light incident on the first and second major surfaces at an angle of 15° or less; and an average transmittance calculated from 400 nm to 700 nm of more than 80% for light incident on the first and second major surfaces at an incident angle of 15° or less, and relates to a window according to aspect (15).

[0026] Aspect (20) of the present disclosure relates to a window for a detection system, comprising: a first glass ply having a first major surface, a second major surface opposite the first major surface, and a first thickness extending between the first major surface and the second major surface; a second glass ply having a third major surface, a fourth major surface opposite the third major surface, and a second thickness extending between the third major surface and the fourth major surface; an intermediate layer disposed between the first glass ply and the second glass ply, coupling the second major surface to the third major surface; and one or more laminated films disposed on at least one of the first major surface and the fourth major surface, each of the one or more laminated films comprising alternating layers of one or more high refractive index materials and one or more low refractive index materials. Without including the one or more laminated films, the first glass ply, the second glass ply, and the intermediate layer, in combination, have an average transmittance of greater than 90% over a 50 nm wavelength range of interest, the 50 nm wavelength range of interest being included in the wavelength range from 800 nm to 1800 nm. The alternating layers of the one or more laminated films are configured to exhibit an average transmittance of 95% or more over a 50 nm wavelength range of interest for light normally incident on the window at the first major surface or the fourth major surface. The alternating layers of the one or more laminated films are configured to exhibit an average reflectance of 5% or less over a 50 nm wavelength range of interest for light normally incident on the window at the first major surface or the fourth major surface. The first thickness is at least twice as thick as the second thickness, and the second glass ply is strengthened to a greater extent than the first glass ply such that the second glass ply exhibits a central tension greater than the central tension of the central region of the first glass ply.

[0027] Aspect (21) of the present disclosure relates to a window according to aspect (20), wherein the first glass ply is not strengthened.

[0028] Aspect (22) of the present disclosure relates to a window according to any of aspects (20)-(21), wherein the first thickness is 2.0 mm or more and 8.0 mm or less, and the second thickness is 0.1 mm or more and 1.2 mm or less.

[0029] Aspect (23) of the present disclosure relates to a window according to any of aspects (20)-(22), in which both the first glass ply and the second glass ply are formed from aluminosilicate glass.

[0030] Aspect (24) of the present disclosure relates to a window according to any of aspects (20)-(23), in which the first glass ply is formed from a glass that exhibits specific fracture behavior when a Vickers indenter test is performed.

[0031] Aspect (25) of the present disclosure relates to a window according to aspect (24), in which the first glass ply is made from a borosilicate glass composition.

[0032] Aspect (26) of the present disclosure relates to a window according to aspect (25), in which, with respect to the constituent oxides, the borosilicate glass composition contains SiO2, B2O3, Al2O3, one or more alkali metal oxides, and one or more divalent cation oxides selected from the group consisting of MgO, CaO, SrO, BaO, and ZnO, 11 mol% or more and 16 mol% or less of B2O3, 2 mol% or more and 6 mol% or less of Al2O3, and a total of 7.0 mol% or more of Na2O, K2O, MgO, and CaO, and the concentrations of the oxide-based molar percentages of SiO2, B2O3, one or more alkali metal oxides, Al2O3, and one or more alkaline earth metal oxides satisfy the relational expressions: (R2O + R’O) ≧ Al2O3 and 0.80 < (1 - [(2R2O + 2R’O) / (SiO2 + 2Al2O3 + 2B2O3)]) < 0.93, where R2O is the total concentration of one or more alkali metal oxides and R’O is the total concentration of one or more alkaline earth metal oxides.

[0033] Aspect (27) of the present disclosure relates to a window according to any of aspects (20)-(26), in which the first thickness is at least three times thicker than the second thickness.

[0034] Aspect (28) of the present disclosure relates to a window according to any of aspects (20)-(27), wherein the second glass ply is chemically strengthened such that the second glass ply has a surface compressive stress on a fourth major surface of 250 MPa or more and 900 MPa or less.

[0035] Aspect (29) of the present disclosure relates to a window according to aspect (28), wherein no crack that penetrates all of the second thickness is formed when the first glass ply collides with a 1 g ball bearing moving at 160.93 km / h.

[0036] Aspect (30) of the present disclosure relates to a window according to any of aspects (20)-(29), wherein the intermediate layer is made of an optically transparent adhesive or an ultraviolet curable acrylic resin.

[0037] Aspect (31) of the present disclosure relates to a window according to aspect (30), wherein the intermediate layer has a third thickness of 0.05 mm or more and 1.0 mm or less.

[0038] Aspect (32) of the present disclosure relates to a window according to any of aspects (20)-(31), wherein the wavelength range of interest of 50 nm is centered at a wavelength between 900 nm and 950 nm.

[0039] Aspect (33) of the present disclosure relates to a window according to any of aspects (20)-(31), wherein the wavelength range of interest of 50 nm is centered at a wavelength between 1525 nm and 1575 nm.

[0040] Aspect (34) of the present disclosure relates to a window according to any of aspects (20)-(33), wherein the one or more laminated films include a first laminated film disposed on the first major surface, and the window has a maximum hardness of at least 8 GPa as measured by a Berkovich indenter hardness test on the first laminated film.

[0041] Aspects (35) of the present disclosure include a second laminated film disposed on a fourth major surface, wherein the quantity, thickness, number, and material of the alternating layers of the first and second laminated films are such that the window has an average reflectance, calculated for light incident on the first and second major surfaces at an angle of 15° or less, of less than 0.5% over a 50 nm wavelength range of interest between 1400 nm and 1600 nm; a CIELAB L value of 45 or less for an angle of incidence of 60° or less on the first laminated film; and a CIELAB a and b value of -6.0 or more and 6.0 or less when viewed from the side of the first laminated film, relates to a window according to aspect (34). * value; and a CIELAB a * and b * value such that, relates to a window according to aspect (35), which is configured to have.

[0042] Aspects (36) of the present disclosure relate to a window according to aspect (35), wherein one of the alternating layers of the first laminated film furthest from the first major surface forms the end face material of the window, the end face material of the window is made of a low refractive index material, the first laminated film is formed from one of one or more high refractive index materials, and includes a scratch-resistant layer having a thickness of 1500 nm or more and 5000 nm or less.

[0043] Aspects (37) of the present disclosure relate to a window according to aspect (36), wherein the scratch-resistant layer is separated from the end face by a plurality of layers within the alternating layers of one or more low refractive index materials and one or more high refractive index materials of the first laminated film, and the scratch-resistant layer is separated from the end face by at least 1000 nm.

[0044] Aspects (38) of the present disclosure include a second laminated film disposed on a fourth major surface, wherein the quantity, thickness, and material of the alternating layers of the first and second laminated films are such that the window has an average transmittance, calculated over a 50 nm wavelength range of interest, of greater than 90% for light incident on the first and second major surfaces at an incident angle of 15° or less; an average reflectance, calculated over a 50 nm wavelength range of interest, of less than 0.5% for light incident on the first and second major surfaces at an angle of 15° or less; and an average transmittance, calculated from 400 nm to 700 nm, of greater than 80% for light incident on the first and second major surfaces at an incident angle of 15° or less, relating to a window according to aspect (34).

[0045] Aspects (39) of the present disclosure relate to a sensor system including an emitter that emits radiation in a 50 nm wavelength range of interest included in the wavelength range from 800 nm to 1800 nm; a sensor configured to detect the radiation emitted by the emitter; an enclosure that defines a sensor cavity housing the emitter and the sensor; and a window according to any one of aspects (21)-(38), the window being attached to the enclosure so as to seal the sensor cavity.

[0046] Aspects (40) of the present disclosure relate to a sensor system according to aspect (39), wherein a second glass ply has dimensions larger than those of a first glass ply, and the second glass ply is attached to the enclosure such that the first major surface is flush with the front surface of the enclosure.

[0047] Aspects (41) of the present disclosure relate to a sensor system according to aspect (40), wherein the sensor cavity remains sealed after a 1 g ball bearing moving at 160.93 km / h impacts the window at an incident angle of 45°.

[0048] Additional features and advantages are described in the following detailed description, some of which will be readily apparent to those of ordinary skill in the art from that description, or will be recognized by practicing the embodiments as described herein, which include the following detailed description, the claims, and the accompanying drawings.

[0049] It is to be understood that both the foregoing general description and the following detailed description are exemplary and intended to provide an overview or framework for understanding the nature and characteristics of the claims. The accompanying drawings are included to provide a further understanding and are incorporated in and constitute a part of this specification. The drawings illustrate one or more embodiments and, together with the description, serve to explain the principles and operation of the various embodiments.

Brief Description of the Drawings

[0050]

Figure 1

Figure 2

Figure 3A

Figure 3B

Figure 4

Figure 5

Figure 6A

Figure 6B

Figure 6C

Figure 7

DETAILED DESCRIPTION OF THE INVENTION

[0051] Here, a detailed reference is made to an embodiment of a window for use in infrared detection applications such as LIDAR sensors. Whenever possible, the same reference numbers are used throughout the drawings to refer to the same or similar components. The window described herein constitutes an asymmetric laminate including a first glass ply, a second glass ply, and an intermediate layer that bonds the first glass ply to the second glass ply. The first glass ply has a first thickness and forms the outer surface of the window that faces the external environment of the sensor when the window is attached to the enclosure. The second glass ply has a second thickness and forms the inner surface of the window that faces the other components of the sensor (e.g., emitters and detectors) when the window is attached to the enclosure. The first thickness is substantially thicker than the second thickness (e.g., at least 2.0 times thicker, at least 2.5 times thicker, at least 3.0 times thicker, at least 3.5 times thicker, at least 4.0 times thicker, at least 4.5 times thicker, at least 5.0 times thicker). In an embodiment, the first glass ply is less strengthened than the second glass ply (e.g., thermally, mechanically, chemically strengthened) such that the second glass ply exhibits a central tension greater than the central tension in the central region of the first glass ply. The second glass ply also exhibits a compressive stress that extends from its major surface to the central region to provide impact resistance and mechanical strength. When bonded between the first and second glass plies by the intermediate layer described herein, the intermediate layer can also serve to dissipate the energy from an impact event by absorbing the energy due to the impact, dissipating the energy, and making crack propagation less likely.

[0052] The asymmetric laminate structure of the window described herein addresses various failure mechanisms related to vehicle-mounted sensor systems. A common cause of window breakage in vehicle-mounted sensor systems is damage due to stone impact. Stone impact can result in window breakage through several mechanisms including blunt (Hertzian) contact, sudden contact, and bending. Blunt contact starts from an existing scratch on the outer surface and then creates a ring / conical crack that penetrates the thickness of the window. Sudden contact creates damage that penetrates the thickness of the window and then creates radial / central cracks, and the bending of the window promotes existing scratches. Bending spreads existing scratches in the window and results in breakage. The asymmetric laminate structure of the window described herein addresses all three of these mechanisms that result in breakage. The increase in the thickness of the first glass ply increases, for example, the distance that the damage from sudden contact must propagate before radial / central breakage occurs, thus making such breakage less likely to occur. The relatively high strengthening of the second glass ply provides a high flexural strength and makes flexural breakage less likely to occur. The low central tension of the first glass ply also helps to resist crack propagation of scratches from subsurface damage by reducing the crack propagation energy stored in the glass. As a result, the asymmetric laminate structure of the window described herein makes breakage and crack propagation from various scratches less likely to occur, thereby improving the lifespan and reliability of vehicle-mounted sensor systems.

[0053] As described herein, the windows described herein exhibit greater impact resistance than certain existing monolithic glass plies having the same or greater thickness. Such impact resistance makes it less likely for breakage and crack propagation to occur in either the first or second glass ply. Radial / central cracks in either glass ply can scatter light passing through the window (e.g., from an emitter associated with a sensor) and may adversely affect the performance of the sensor, so such durability is particularly beneficial for sensor applications. Further, in certain sensors, such as LiDAR sensors, the sensor components may be housed within a sealed sensor cavity to provide reliable performance over the lifespan of the sensor. The improved impact resistance of the windows described herein is beneficially useful for maintaining the seal integrity of the sensor cavity even when the window is exposed to relatively harsh impact events. As described herein, a window according to the present disclosure can maintain the seal integrity of the sensor cavity when a 1 g ball bearing moving at 160.93 km / h impacts at an angle of 45° with respect to the first glass ply. Existing monolithic windows may not be able to maintain seal integrity for impacts at half this speed, even when having a greater thickness than the windows described herein. The reduction in thickness can further improve impact performance by dissipating energy through flexure.

[0054] The materials of each component of the window described in this specification can also be selected to favorably affect durability and impact resistance. For example, in an embodiment, the first glass ply is made of a glass that tends to exhibit specific crack behavior when in contact with a Vickers indenter, as described in this specification. Such glass is resistant to central / radial crack propagation and can withstand damage from a collision event in the region closest to the initial collision point, thereby tending to minimize harmful optical effects. In addition, the inner glass ply can be formed from chemically strengthened glass (e.g., alkali aluminosilicate glass, alkali aluminoborosilicate glass) to provide a relatively large amount of compressive stress (e.g., at least 250 MPa) on its major surface to provide high surface strength and bending strength.

[0055] The materials of each of the components of the asymmetric laminate structure described in this specification are also selected to exhibit favorable optical performance in the wavelength range of interest related to the sensor. For example, in an embodiment, both the first and second glass plies can be formed from a glass that exhibits a relatively high light transmittance (e.g., an average transmittance of 95% or more) over a 50 nm wavelength range of interest related to a particular sensor application. The 50 nm wavelength range of interest may be included within the wavelength range of 800 nm to 1800 nm (e.g., the 50 nm wavelength range of interest may include a central wavelength ranging from 925 nm to 975 nm, or from 1525 nm to 1725 nm).

[0056] The material of the intermediate layer can also be selected to have an average transmittance of 98% or more (e.g., 98.25% or more, 98.5% or more, 98.75% or more, 99.0% or more, 99.25% or more) alone (e.g., excluding other components of the window) over the 50 nm wavelength range of interest. As a result, the first glass ply, the second glass ply, and the intermediate layer can exhibit an average transmittance of more than 90% (e.g., 90.25% or more, 90.5% or more, 90.75% or more, 91.0% or more, 91.25% or more) over the 50 nm wavelength range of interest in combination (excluding additional laminated films / coatings). Such optical performance is superior to that obtained when using a typical polymer intermediate layer (such as a polyvinyl butyral intermediate layer) for assembling the glass laminate. In an embodiment, the intermediate layer includes a layer of an optically transparent adhesive or an ultraviolet curable acrylic resin with a thickness of 0.05 mm to 1.5 mm. Such materials provide the above-described optical performance while securely bonding the glass plies to each other.

[0057] The optical performance attributes of the windows described herein can also be improved by including one or more laminated films on the major surfaces of the first and second glass plies. In an embodiment, for example, the windows described herein are made from alternating layers of a high refractive index material and a low refractive index material and are made to provide a relatively high transmittance and a low reflectance in a 50 nm wavelength range of interest, and can include first and second laminated films disposed on the first and second glass plies, respectively. When such a window is attached to a LIDAR system, the first laminated film can face outward and be exposed to the external environment as seen from the sensor / electromagnetic radiation emitter, while the second laminated film can face the sensor / electromagnetic radiation emitter. That is, when viewing the LIDAR system from the outside, an observer can see the first laminated film. Light emitted by the electromagnetic radiation emitter can first be incident on the second laminated film before passing through the substrate. According to the present disclosure, the first laminated film of the windows described herein can include one or more scratch-resistant layers that are relatively thick (e.g., 500 nm or more) of a high refractive index material. The scratch-resistant layer can be embedded within the first laminated film such that the window has a maximum nanoindentation hardness of 8 GPa or more (e.g., 10 GPa or more, 12 GPa or more, 14 GPa or more) when measured with the first laminated film by a Berkovich indenter hardness test. Such nanoindentation hardness beneficially provides scratch resistance and improves the performance of the LIDAR system.

[0058] In an aspect, the alternating layers of the first and second laminated films of the window described herein are also configured to provide optical performance attributes desirable for the operation of a LIDAR system in the infrared spectrum. In embodiments, the thickness, number, and materials of the alternating layers of the first and second laminated films are such that the window is made to have an average transmittance of 95% or more calculated over a wavelength range of 50 nm for light incident normal to the window. The quantity, thickness, number, and materials of the alternating layers of the first and second laminated films can be made such that the window has the following average reflectance calculated over a wavelength range of 50 nm for light incident normal to the window.

[0059] Thus, the window described herein contains an asymmetric laminate structure combined with at least one laminated film including an abrasion-resistant layer on a first glass ply, providing improved puncture and abrasion resistance performance, thereby significantly improving the lifespan and reliability of a vehicle-based detection system while providing favorable optical performance characteristics in a desired wavelength range of interest.

[0060] Unless otherwise specified, the total reflectance, specular reflectance, and average reflectance values given herein are two-surface reflectance values and represent the total reflectance of the entire window, including the reflectance associated with each material interface in the window (e.g., between air and the laminated film, between the laminated film and the substrate, etc.). Unless otherwise specified, the reflectance values given in the infrared are measured from the side of the second laminated film described herein (e.g., from the side facing the sensor / emitter of the LIDAR system), and the reflectance values given in the visible are measured from the side of the first laminated film described herein (e.g., from the side facing the external environment of the LIDAR system).

[0061] Unless otherwise specified herein, the values of the average transmittance and the average reflectance are calculated using the reflectance values and the transmittance values at various wavelengths within a specific wavelength range. The values of the average reflectance and the average transmittance can be calculated by measuring the reflectance and transmittance values every one-fifth of an integer wavelength (including the endpoints) within the desired wavelength range and averaging those values (for example, when calculating the average transmittance over a wavelength range from 1540 nm to 1560 nm, the transmittance values can be measured and averaged at 1540 nm, 1545 nm, 1550 nm, 1555 nm, and 1560 nm).

[0062] Unless otherwise specified herein, the a * and b * in the CIELAB color space, as well as the lightness L * values are measured / simulated using a D65 light source.

[0063] As used herein, the term "dark appearance" or "black appearance" refers to the reflective appearance of the window when viewed from the outside. A window having a dark appearance or a black appearance according to the present disclosure has a CIELAB lightness L * value of less than 45 when viewed from an angle of 60° or less.

[0064] As used herein, the term "strengthened" when used in relation to a glass ply or a glass layer refers to a glass substrate that can be strengthened in various combinations of chemical, mechanical, thermal, or chemical, mechanical, and / or thermal to provide a compressive stress region having a surface compressive stress value and a central tensile stress region having a maximum CT value. Such a strengthened glass substrate also includes the corresponding surface CS and a compressive stress region extending from the surface to the DOC. Any one or more of the magnitude of the surface CS, the DOC, and the magnitude of the maximum CT value can be adjusted in the strengthening process. As used herein, the DOC refers to the depth at which the stress transitions from compression to tension. Unless otherwise specified, CT and CS are expressed in megapascals (MPa) herein, while the thickness and the DOC are expressed in millimeters or micrometers.

[0065] CS and DOC are measured by a surface stress meter (FSM) using commercially available equipment such as the FSM-6000 manufactured by Orihara Seisakusho Co., Ltd. (Japan). The surface stress measurement depends on the precise measurement of the stress optical coefficient (SOC), which is related to the birefringence of the glass. Next, the SOC is measured according to Procedure C (glass disk method) described in ASTM standard C770-16 entitled "Standard Test Method for Measurement of Glass Stress-Optical Coefficient", the content of which is incorporated herein by reference in its entirety.

[0066] When an FSM is used to measure the compressive stress, CS is related to CT by the following approximate relationship (Equation 1): CT ≒ (CS × DOC) / (thickness - 2 × DOC). In the equation, the thickness is the total thickness of the strengthened glass substrate. A mechanically strengthened glass substrate can include a compressive stress region and a central tensile region caused by a mismatch in the coefficient of thermal expansion between multiple parts of the substrate. A chemically strengthened glass substrate can include a compressive stress region and a central tensile region caused by an ion exchange process. In a chemically strengthened glass substrate, larger ions are exchanged for smaller ions at a temperature lower than the temperature at which the glass network structure can relax, resulting in a distribution of ions across the surface of the glass, thereby creating a stress profile. Since the volume of the penetrating ions is larger, CS is generated in the surface portion of the substrate, and tension (CT) is generated at the center of the glass. In a thermally strengthened substrate, the CS region is formed by heating the substrate to a high temperature above the glass transition temperature close to the softening point of the glass and then cooling the surface region of the glass more rapidly than the interior region of the glass. The difference in the cooling rate between the surface region and the interior region results in a residual surface CS, which in turn gives rise to a CT corresponding to the central region of the glass.

[0067] Unless otherwise specified, it is never intended that any method described in this specification be construed as requiring that its steps be performed in a particular order. Thus, where a method claim does not actually recite the order to be followed by its steps, or where no particular order for the steps is otherwise specifically recited in the claim or the specification, no order should be implied in any respect. This applies to any possible non-expression criteria for interpretation, including the arrangement of steps, the flow of operations; the plain meaning derived from the grammatical construction or punctuation; or the logical matters regarding the number or type of embodiments described in this specification.

[0068] As used herein, the term "and / or" when used in a list of two or more items means that any one of the listed items can be used by itself or any combination of two or more of the listed items can be used. For example, if a composition is described as containing component A, B, and / or C, the composition can contain A only, B only, C only, a combination of A and B, a combination of A and C, a combination of B and C, or a combination of A, B, and C.

[0069] Modifications of the present disclosure will be apparent to those skilled in the art and those making or using the present disclosure. Accordingly, the embodiments shown in the drawings and described above are for illustrative purposes only and are not intended to limit the scope of the present disclosure, which scope is to be defined by the following claims in accordance with the principles of patent law, including the doctrine of equivalents, as will be understood.

[0070] In this document, relational terms such as first and second, top and bottom, etc. are used only to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. The terms "comprises", "comprising", or any other variation thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements does not include only those elements but may contain other elements not expressly listed or inherent to such process, method, article, or apparatus. An element that precedes "comprising" does not, without more constraints, preclude the existence of additional identical elements in the process, method, article, or apparatus that includes that element.

[0071] As used herein, the term "about" means that a quantity, size, formulation, parameter, and other quantities and characteristics are not exact and need not be exact, but may be approximate and / or greater or less than as appropriate, reflecting tolerances, conversion factors, rounding, measurement errors, and other factors known to those of skill in the art. When the term "about" is used in describing a value or the endpoint of a range, the present disclosure is to be understood as including the particular value or endpoint being referred to. Whether or not the numerical or range endpoint is preceded by the term "about" in the specification, the numerical or range endpoint is intended to include two embodiments, one modified by "about" and one not modified by "about". It will be further understood that each endpoint of a range is significant both in relation to the other endpoint and independently of the other endpoint.

[0072] The term "formed from" can mean including, consisting essentially of, or consisting of one or more of. For example, a component formed from a particular material may include that particular material, may consist essentially of that particular material, or may consist of that particular material.

[0073] The term "disposed" is used herein to refer to a layer or sub-layer that is coated, deposited, formed, or otherwise provided on a surface. The term "disposed" can include a layer / sublayer provided in direct contact with an adjacent layer / sublayer, or a layer / sublayer separated by an intervening material that may or may not form a layer.

[0074] Referring now to FIG. 1, vehicle 10 includes one or more LIDAR systems 12. The one or more LIDAR systems 12 can be disposed anywhere on or within vehicle 10. For example, the one or more LIDAR systems 12 can be disposed on roof 14 of vehicle 10 and / or front portion 16 of vehicle 10.

[0075] Referring now to FIG. 2, each of the one or more LIDAR systems 12 includes an electromagnetic radiation emitter-sensor 18, as is known in the art, which can be housed within an enclosure 20. The enclosure 20 may be a housing formed from a suitable material (e.g., metal or polymeric material) to protect the radiation emitter-sensor 18 from the external environment 26. The LIDAR system 12 further includes a window 24 attached to the enclosure 20 to form a sensor cavity 15. In an embodiment, the window 24 is attached to the enclosure 20 such that the sensor cavity 15 is sealed to prevent particles and other debris from the external environment from entering the sensor cavity 15 and degrading the performance of the LIDAR system 12. The window 24 may be coupled to the enclosure 20 using any suitable connection method. In an embodiment, the window 24 is attached to the front face (e.g., of the sidewall) of the enclosure 20 using a suitable adhesive. In an embodiment, the window 24 is attached to the enclosure 20 by one or more fasteners passing through at least one glass layer (e.g., an un-reinforced first glass ply as described herein). In an embodiment, one or more layers of the asymmetric laminate described herein may have different dimensions to facilitate attachment of the window 24 to the enclosure 20. For example, the first outer glass ply may have a dimension smaller than that of the second inner glass ply, and the window 24 may be bezel-mounted within the enclosure 20 such that the outer face of the window 24 is flush with the front face of the enclosure. Any suitable connection method may be used.

[0076] In an embodiment, the electromagnetic radiation emitter-sensor 18 emits emitted radiation 22 having a certain wavelength or wavelength range (e.g., within a 50 nm wavelength range of interest included in the wavelength range from 800 nm to 1800 nm). The emitted radiation 22 exits the outer enclosure 20 through the window 24 that is in the path of the emitted electromagnetic radiation. When an object (not shown) in the external environment 26 is in the path of the emitted radiation 22, the emitted radiation 22 is reflected by the object and returns to the electromagnetic radiation emitter-sensor 18 as reflected radiation 28. The reflected radiation 28 passes through the window 24 again and reaches the electromagnetic radiation emitter-sensor 18. In an embodiment, the emitted radiation 22 and the reflected radiation 28 can include light within a suitable wavelength range of interest from 800 nm to 1800 nm. For example, the emitted radiation 22 and the reflected radiation 28 may be within a suitable 50 nm wavelength range. This 50 nm wavelength range may have a center wavelength (e.g., the wavelength of the maximum intensity of the emitted radiation 22) that varies depending on the application. The center wavelength may be, in some embodiments, 925 nm or more and 975 nm or less, and 1525 nm or more and 1575 nm or less. In an embodiment, the emitted radiation 22 and the reflected radiation 28 may be 1400 nm or more and 1600 nm or less (e.g., 1500 nm or more and 1600 nm or less, 1525 nm or more and 1575 nm or less, about 1550 nm, 1550 nm). Electromagnetic radiation other than the reflected radiation 28 (electromagnetic radiation having wavelengths in the visible spectrum, portions of the ultraviolet range, etc.) may also interact with the window 24. As described herein, the window 24 can be designed to provide desired performance attributes across such wavelength ranges by incorporating one or more laminated films.

[0077] As described herein, the "visible spectrum" is the portion of the electromagnetic spectrum that is visible to the human eye and generally refers to electromagnetic radiation having wavelengths in the range of about 380 nm or 400 nm to about 700 nm. The "ultraviolet range" is the portion of the electromagnetic spectrum having wavelengths between about 10 nm and about 400 nm. The "infrared range" of the electromagnetic spectrum begins at about 700 nm and extends to longer wavelengths. The sun produces solar electromagnetic radiation, generally referred to as "sunlight", having wavelengths that fall into all three of these ranges.

[0078] Referring now to FIG. 3A, each window 24 of one or more LIDAR systems 12 includes a substrate 30. The substrate 30 has a first surface 32 and a second surface 34. The first surface 32 and the second surface 34 are the major surfaces of the substrate 30. The second surface 34 is closest to the electromagnetic radiation emitter / sensor 18. The emitted radiation 22 reaches the second surface 34 before reaching the first surface 32. The reflected radiation 28 reaches the first surface 32 before reaching the second surface 34. The substrate 30 has a first layer film 36 disposed on the first surface 32 of the substrate 30, and optionally, a second layer film 38 is disposed on the second surface 34 of the substrate 30. Examples where the window 24 includes both the first layer film 36 and the second layer film 38 are described herein. Embodiments where the window 24 includes only a single layer film (e.g., only the first layer film 36 or only the second layer film 38) are also contemplated. It should be understood that the window 24 described herein is not limited to vehicle applications and may be used in any application where the window 24 would be useful to provide improved impact performance and optical performance as further described herein.

[0079] Referring now to FIG. 3B, the components of the substrate 30 are shown in more detail. As can be seen from the figure, the substrate 30 constitutes an asymmetric laminate structure 300, which structure 300 includes a first glass ply 200 having a first thickness 205, a second glass ply 320 having a second thickness 325, and an intermediate layer 330 that bonds the first glass ply 200 to the second glass ply 320 and has a third thickness 335. The first glass ply 200 has a first major surface 202 and a second major surface 204. The thickness 205 extends between the first major surface 202 and the second major surface 204 in a direction perpendicular to the first major surface 202. The first major surface 202 forms the first surface 32 of the substrate 30 (e.g., such that the first major surface 202 faces the external environment 26 shown in FIG. 2). The second glass ply 320 has a third major surface 332 and a fourth major surface 334. The second thickness 325 extends between the third major surface 332 and the fourth major surface 334 in a direction perpendicular to the third major surface 332. The fourth major surface 334 forms the second surface 34 of the substrate 30 (e.g., such that the fourth major surface 334 faces the sensor cavity 15 shown in FIG. 2).

[0080] In an embodiment, the first thickness 205 is substantially thicker than the second thickness 325. For example, in an embodiment, the first thickness 205 is at least 2.0 times thicker than the second thickness (e.g., at least 2.5 times thicker, at least 3.0 times thicker, at least 3.5 times thicker, at least 4.0 times thicker, at least 4.5 times thicker, at least 5.0 times thicker). In an embodiment, the ratio between the first thickness 205 and the second thickness 325 (first thickness / second thickness) is greater than 2:1, for example, in the range from 2:1 to 20:1, from 3:1 to 20:1, from 3:1 to 15:1, from 3:1 to 10:1, from 4:1 to 20:1, from 4:1 to 15:1, from 4:1 to 10:1, from 4.5:1 to 20:1, from 4.5:1 to 15:1, from 4.5:1 to 10:1, from 5:1 to 20:1, from 5:1 to 15:1, from 5:1 to 10:1, from 5.75:1 to 20:1, from 5.75:1 to 15:1, or from 5.75:1 to 10:1. As described herein, such an asymmetric structure 300 beneficially improves the impact performance of the window 24.

[0081] In an embodiment, the first thickness 205 is at least 0.5 mm, at least 1 mm, at least 2 mm, at least 3 mm, at least 3.3 mm, or at least 3.8 mm. In one or more embodiments, the first thickness is from about 1.5 mm to about 8 mm, from 1.6 mm to about 8 mm, from about 1.8 mm to about 8 mm, from about 2 mm to about 8 mm, from about 2.2 mm to about 8 mm, from about 2.4 mm to about 8 mm, from about 2.6 mm to about 8 mm, from about 2.8 mm to about 8 mm, from about 3 mm to about 8 mm, from about 3.1 mm to about 8 mm, from about 3.2 mm to about 8 mm, from about 3.3 mm to about 8 mm, from about 3.4 mm to about 8 mm, from about 3.5 mm to about 8 mm, from about 3.6 mm to about 8 mm, from about 3.7 mm to about 8 mm, from about 3.8 mm to about 8 mm, from about 3.9 mm to about 8 mm, from about 4 mm to about 8 mm, from about 4.2 mm to about 8 mm, from about 4.4 mm to about 8 mm, from about 4.5 mm to about 8 mm, from about 4.6 mm to about 8 mm, from about 4.8 mm to about 8 mm, from about 5 mm to about 8 mm, from about 5.2 mm to about 8 mm, from about 5.4 mm to about 8 mm, from about 5.5 mm to about 8 mm, from about 5.6 mm to about 8 mm, from about 5.8 mm to about 8 mm, from 1.6 mm to about 5.8 mm, from 1.6 mm to about 5.6 mm, from 1.6 mm to about 5.5 mm, from 1.6 mm to about 5.4 mm, from 1.6 mm to about 5.2 mm, from 1.6 mm to about 5 mm, from 1.6 mm to about 4.8 mm, from 1.6 mm to about 4.6 mm, from 1.6 mm to about 4.4 mm, from 1.6 mm to about 4.2 mm, from 1.6 mm to about 4 mm, from 1.6 mm to about 3.9 mm, from 1.6 mm to about 3.8 mm, from 1.6 mm to about 3.7 mm, from 1.6 mm to about 3.6 mm, from 1.6 mm to about 3.5 mm, from 1.6 mm to about 3.4 mm, from 1.6 mm to about 3.3 mm, from 1.6 mm to about 3.2 mm, from 1.6 mm to about 3.1 mm, from 1.6 mm to about 3 mm, from 1.6 mm to about 2.8 mm, from 1.6 mm to about 2.6 mm, from 1.6 mm to about 2.4 mm, from 1.6 mm to about 2.2 mm, from 1.6 mm to about 2 mm, from 1.6 mm to about 1.8 mm, from 3 mm to about 5 mm, or from about 3 mm to about 4 mm.

[0082] In one or more embodiments, the second thickness 325 may be in the range of from about 0.05 mm to about 1.5 mm, such as from about 0.05 mm to about 1.2 mm, from about 0.05 mm to about 1.1 mm, from about 0.05 mm to about 1.0 mm, from about 0.05 mm to about 0.9 mm, in the range of from about 0.05 to about 0.8 mm, in the range of from about 0.05 to about 0.7 mm, in the range of from about 0.05 to about 0.6 mm, in the range of from about 0.05 to about 0.5 mm, in the range of from about 0.05 to about 0.4 mm, in the range of from about 0.05 to about 0.3 mm, in the range of from about 0.05 to about 0.2 mm, or in the range of from about 0.05 to about 0.15 mm.

[0083] The thicknesses described herein are maximum thicknesses. In one or more embodiments, the first glass ply 200 and the second glass ply 320 have a substantially uniform thickness. In an embodiment, the first thickness 205 and the second thickness 305 may vary depending on the spatial position. Although the illustrated embodiments are flat, embodiments in which one or more of the first glass ply 200 and the second glass ply 320 are curved by suitable techniques (such as thermoforming or cold forming) are also contemplated.

[0084] In an embodiment, the first glass ply 200 is strengthened to a lesser extent than the second glass ply 320 such that the first glass ply 200 and the second glass ply 320 have different stress distributions therein (for example, apart from the external force applied to the substrate 30). The first glass ply 200 generally has a central tension that is less than the central tension of the central region of the second glass ply 320. In an embodiment, for example, the second glass ply 320 is strengthened and the first glass ply 200 is not strengthened (however, it may be annealed as needed), and thus, the first glass ply exhibits a surface compressive stress of less than about 10 MPa, less than about 3 MPa, or less than or equal to about 2.5 MPa, 2 MPa, 1.5 MPa, 1 MPa, or about 0.5 MPa. In such an embodiment, the second glass ply 320 may be strengthened thermally, mechanically, or chemically. In an embodiment, for example, the second glass ply 320 is chemically strengthened such that the second glass ply 320 has a surface compressive stress of at least 250 MPa, at least 300 MPa, or at least 400 MPa, or at least 500 MPa, or at least 600 MPa, or at least 700 MPa, at least 800 MPa, at least 900 MPa, or at least 1000 MPa on the third major surface 332 and the fourth major surface 334. In various embodiments, the second glass ply 320 has a surface compressive stress magnitude on one or more of the third major surface 332 and the fourth major surface 334 that is in the range of about 250 MPa to about 1100 MPa, about 250 MPa to about 900 MPa, about 300 MPa to about 900 MPa, about 400 MPa to about 900 MPa, or in the range of about 500 MPa to about 900 MPa, or in the range of about 600 MPa to about 900 MPa, or in the range of about 700 MPa to about 900 MPa, or in the range of about 800 MPa to about 900 MPa.

[0085] In an embodiment, the second glass ply 320 may include at least one region of compressive stress that extends from one or more of the third major surface 332 and the fourth major surface 334 to a depth of compression (DOC). In an embodiment, the DOC is 15 μm or more, 20 μm or more, 25 μm or more, 30 μm or more, 35 μm or more, 40 μm or more, 45 μm or more, or 50 μm or more. In an embodiment, the DOC is in the range of about 30 μm to about 150 μm, in the range of about 30 μm to about 90 μm, or in the range of about 40 μm to about 80 μm, or in the range of about 40 μm to about 70 μm, or in the range of about 40 μm to about 60 μm, or in the range of about 40 μm to about 50 μm.

[0086] The materials of the first glass ply 200 and the second glass ply 320 may be different. According to one or more embodiments, the materials of the first glass ply 200 and the second glass ply 320 may be the same material (except for differences resulting from strengthening treatment) or different materials. In an exemplary embodiment, one or both of the first glass ply 200 and the second glass ply 320 may be glass (e.g., soda-lime glass, alkali aluminosilicate glass, alkali-containing borosilicate glass, and / or alkali aluminoborosilicate glass) or glass ceramic (a glass ceramic containing any one or more crystal phases of Li2O·Al2O3·SiO2-based (i.e., LAS-based) glass ceramic, MgO·Al2O3·SiO2-based (i.e., MAS-based) glass ceramic, mullite, spinel, α-quartz, β-quartz solid solution, leaf feldspar, lithium disilicate, β-spodumene, nepheline, and alumina).

[0087] The first glass ply 200 and the second glass ply 320 may be provided using a variety of different processes. Exemplary glass substrate forming methods include the float glass method and down-draw methods such as the fusion draw method and the slot draw method. A glass substrate prepared by the float glass method can be characterized by a smooth surface, and a uniform thickness is created by floating molten glass on a bath of molten metal, typically tin. In an exemplary process, the molten glass supplied to the surface of the molten tin bed forms a floating glass ribbon. As the glass ribbon flows along the tin bath, the temperature gradually decreases until the glass ribbon solidifies into a solid glass substrate that can be pulled up from the tin onto a roll. Once the glass substrate is removed from the bath, it can be further cooled and annealed to reduce internal stress.

[0088] In the down-draw method, a glass substrate with a relatively pristine surface and a uniform thickness is produced. Since the average bending strength of the glass substrate is controlled by the amount and size of surface defects, a pristine surface with minimal contact has a higher initial strength. When this high-strength glass substrate is further strengthened (e.g., chemically), the resulting strength can be higher than that of a glass substrate with a lapped and polished surface. A glass substrate produced by the down-draw method can be drawn to a thickness of less than about 2 mm. In addition, a glass substrate produced by the down-draw method has a very flat and smooth surface that can be used for end-use applications without the need for costly grinding and polishing.

[0089] In the fusion draw method, for example, a drawing bath having a passage for receiving a molten glass raw material is used. This passage has weirs that open at the top along the longitudinal direction of the passage on both sides of the passage. When the passage is filled with the molten material, the molten glass overflows from the weirs. The molten glass flows downward along the outer surfaces of the drawing bath as two flowing glass films due to gravity. These outer surfaces of the drawing bath extend downward and inward so as to join at the edges below the drawing bath. The two flowing glass films join and fuse at this edge to form a single flowing glass substrate. The fusion draw method presents the advantage that neither of the outer surfaces of the resulting glass substrate contacts any part of the apparatus since the two glass films flowing across the passage fuse together. Therefore, the surface characteristics of the glass substrate produced by the fusion draw method are not affected by such contact.

[0090] The slot draw method is different from the fusion draw method. In the slot draw method, molten raw material glass is supplied to a drawing bath. At the bottom of the drawing bath, a slot is open, and the slot has a nozzle extending along the length of the slot. The molten glass flows through the slot / nozzle and is drawn downward as a continuous substrate into a slow cooling region.

[0091] Once formed, the glass substrate can be strengthened as described herein to form a strengthened glass substrate. It should also be noted that glass-ceramic substrates can be strengthened in the same manner as glass substrates.

[0092] Examples of glass that can be used for the first glass ply 200 or the second glass ply 320 include borosilicate glass compositions, alkali aluminosilicate glass compositions, alkali aluminoborosilicate glass compositions, soda lime silicate glass compositions, and other suitable glass compositions. Some of the glass compositions can be characterized as ion-exchangeable. As used herein, "ion-exchangeable" means that a substrate made from the composition can exchange cations located on or near the surface of the substrate with cations of the same valence that are larger or smaller in size. An example of a glass composition includes SiO2, B2O3, and Na2O, where (SiO2 + B2O3) ≥ 66 mol% and Na2O ≥ 9 mol%. Suitable glass compositions further include at least one of K2O, MgO, and CaO in some embodiments. In certain embodiments, the glass composition used for the substrate can include 61-75 mol% SiO2, 7-15 mol% Al2O3, 0-12 mol% B2O3, 9-21 mol% Na2O, 0-4 mol% K2O, 0-7 mol% MgO, and 0-3 mol% CaO.

[0093] Further exemplary glass compositions suitable for the first and second glass plies 200 and 320 include 60-70 mol% SiO2, 6-14 mol% Al2O3, 0-15 mol% B2O3, 0-15 mol% Li2O, 0-20 mol% Na2O, 0-10 mol% K2O, 0-8 mol% MgO, 0-10 mol% CaO, 0-5 mol% ZrO2, 0-1 mol% SnO2, 0-1 mol% CeO2, less than 50 ppm As2O3, and less than 50 ppm Sb2O3, where 12 mol% ≤ (Li2O + Na2O + K2O) ≤ 20 mol% and 0 mol% ≤ (MgO + CaO) ≤ 10 mol%.

[0094] Additional exemplary glass compositions suitable for the first and second glass plies 200 and 320 include 63.5 to 66.5 mol% SiO₂, 8 to 12 mol% Al₂O₃, 0 to 3 mol% B₂O₃, 0 to 5 mol% Li₂O, 8 to 18 mol% Na₂O, 0 to 5 mol% K₂O, 1 to 7 mol% MgO, 0 to 2.5 mol% CaO, 0 to 3 mol% ZrO₂, 0.05 to 0.25 mol% SnO₂, 0.05 to 0.5 mol% CeO₂, less than 50 ppm As₂O₃, and less than 50 ppm Sb₂O₃, where 14 mol% ≤ (Li₂O + Na₂O + K₂O) ≤ 18 mol%, and 2 mol% ≤ (MgO + CaO) ≤ 7 mol%.

[0095] In certain embodiments, aluminosilicate glass compositions suitable for the first and second glass plies 200 and 320 include alumina, at least one alkali metal, and in some embodiments, greater than 50 mol% SiO₂, in other embodiments, at least 58 mol% SiO₂, and in yet other embodiments, at least 60 mol% SiO₂, where the ratio ((Al₂O₃ + B₂O₃) / Σmodifier) > 1, and in this ratio, the components are expressed in mol% and the modifier is an alkali metal oxide. This glass composition, in certain embodiments, includes 58 to 72 mol% SiO₂, 9 to 17 mol% Al₂O₃, 2 to 12 mol% B₂O₃, 8 to 16 mol% Na₂O, and 0 to 4 mol% K₂O, where the ratio ((Al₂O₃ + B₂O₃) / Σmodifier) > 1.

[0096] In yet another embodiment, the first and second glass plies 200 and 320 may comprise an alkali aluminosilicate glass composition comprising 64 to 68 mol% SiO2, 12 to 16 mol% Na2O, 8 to 12 mol% Al2O3, 0 to 3 mol% B2O3, 2 to 5 mol% K2O, 4 to 6 mol% MgO, and 0 to 5 mol% CaO, where 66 mol% ≦ SiO2 + B2O3 + CaO ≦ 69 mol%, Na2O + K2O + B2O3 + MgO + CaO + SrO > 10 mol%, 5 mol% ≦ MgO + CaO + SrO ≦ 8 mol%, (Na2O + B2O3) - Al2O3 ≦ 2 mol%, 2 mol% ≦ Na2O - Al2O3 ≦ 6 mol%, and 4 mol% ≦ (Na2O + K2O) - Al2O3 ≦ 10 mol%.

[0097] In an alternative embodiment, the first and second glass plies 200 and 320 may be made from an alkali aluminosilicate glass composition comprising 2 mol% or more of Al2O3 and / or ZrO2, or 4 mol% or more of Al2O3 and / or ZrO2.

[0098] In an embodiment, the first glass ply 200 is formed from a unique glass composition. The unique glass is a glass that, when subjected to the Vickers indenter test described in both “Crack-resistant glass with high shear band density, Journal of Non-Crystalline Solids” by Gross et al., 494, (2018) 13-20; and “Deformation and cracking behavior of glasses indented with diamond tips of various sharpness” by Gross, Journal of Non-Crystalline Solids, 358, (2012) 3445-3452, which are both fully incorporated herein by reference, tends to exhibit a crack loop surrounding the initial indentation position or a densification fracture behavior. Examples of unique glasses may be borosilicate glasses (such as those described in the specification of International Patent Application No. PCT / US2021 / 61966 filed on December 6, 2021), certain non-reinforced aluminosilicate glasses, or glasses with a relatively high silica content. Such glasses tend to exhibit favorable impact performance characteristics over glasses that exhibit normal fracture behavior, where cracks radiating from the indentation position tend to penetrate the thickness of the glass and potentially result in catastrophic failure. Unique glasses such as borosilicates may also exhibit a relatively low CTE and tend to limit thermally induced damage due to environmental exposure.

[0099] In an embodiment, the first glass ply 200 is made from a borosilicate glass composition comprising from 60 mol% to 90 mol% SiO2, from about 1 mol% to about 20 mol% Al2O3, from 7 mol% to 16 mol% B2O3, and from 2 mol% to 20 mol% R2O, where R2O represents the total amount of Na2O, Li2O, and K2O. For example, in an embodiment, the borosilicate glass composition comprises about 83.60 mol% SiO2, about 1.20 mol% Al2O3, about 11.60 mol% B2O3, about 3.00 mol% Na2O, and about 0.70 mol% K2O, and about 32×10 -7It has a CTE of / K. Such borosilicate glass is advantageously more thermally shock resistant than the soda-lime silicate glass currently used in certain windows and can be resistant to crack formation due to impact events with road debris (e.g., stones, etc.). Borosilicate glass is known to exhibit unique crack behavior and is not very prone to the formation of cracks that propagate radially from the point of collision with a fragment, which is particularly beneficial for the durability of automotive sheet glass.

[0100] In an embodiment, the first glass ply 200 is made from one of the fusion formable borosilicate glass compositions described in U.S. Provisional Patent Application No. 63 / 123,863, filed December 10, 2020, entitled "Fusion Formable Borosilicate Glass Composition and Articles Formed Therefrom", U.S. Provisional Patent Application No. 63 / 183,271, filed May 3, 2021, entitled "Fusion Formable Borosilicate Glass Composition and Articles Formed Therefrom", U.S. Provisional Patent Application No. 63 / 183,292, filed May 3, 2021, entitled "Glass with Unique Fracture Behavior for Vehicle Windshield", U.S. Patent Application No. 17 / 363,266, filed June 30, 2021, entitled "Glass with Unique Fracture Behavior for Vehicle Windshield", International Patent Application No. PCT / US2021 / 061966, filed December 6, 2021, entitled "Glass with Unique Fracture Behavior for Vehicle Windshield", and U.S. Provisional Patent Application No. 63 / 341,603, filed May 13, 2022, entitled "Glass with Unique Fracture Behavior for Vehicle Windshield", the entire contents of each of which are hereby incorporated by reference. In an embodiment, such a borosilicate glass composition includes, with respect to constituent oxides, SiO2, B2O3, Al2O3, one or more alkali metal oxides, and one or more divalent cation oxides selected from the group consisting of MgO, CaO, SrO, BaO, and ZnO. In an embodiment, the borosilicate glass composition includes, for example, 11 mol% or more and 16 mol% or less of B2O3, 2 mol% or more and 6 mol% or less of Al2O3, and a total of 7.0 mol% or more of Na2O, K2O, MgO, and CaO.The concentrations of SiO2, B2O3, one or more alkali metal oxides, Al2O3, and one or more alkaline earth metal oxides in mole percent on an oxide basis satisfy the relational expressions: (R2O + R’O) ≧ Al2O3 and 0.80 < (1 - [(2R2O + 2R’O) / (SiO2 + 2Al2O3 + 2B2O3)]) < 0.93, where R2O is the sum of the concentrations of one or more alkali metal oxides and R’O is the sum of the concentrations of one or more alkaline earth metal oxides. Such glass has been found to exhibit a favorable ring cracking behavior that prevents the radial propagation of cracks from the point of impact.

[0101] In an embodiment, the first glass ply 200 contains 74 mol% to 80 mol% Si, 2.5 mol% to 6 mol% Al, 11.5 mol% to 18 mol% B, 4.5 mol% to 8 mol% Na, 0.5 mol% to 3 mol% K, 0.5 mol% to 2.5 mol% MgO, and 0 mol% to 4 mol% CaO (for example, such that the total amount of CaO and MgO is less than 5 mol%), and 32.5×10 -7 / K or more and 56×10 -7 / K or less, (for example, 40×10 -7 / K or more and 50×10 -7 / K or less, 42×10 -7 / K or more and 48×10 -7 / K or less, 43×10 -7 / K or more and 47×10 -7It is made from a fusion - formable borosilicate glass composition having a CTE of less than or equal to / K. Such a fusion - formable glass composition has concentrations that satisfy the relational expressions: (Relational Expression 1) SiO2≥72 mol%, for example, SiO2≥72.0, for example, SiO2≥73.0, for example, SiO2≥74.0, and / or SiO2≤92, for example, SiO2≤90; (Relational Expression 2) B2O3≥10 mol%, for example, B2O3≥10.0, for example, B2O3≥10.5, and / or B2O3≤20, for example, B2O3≤18; (Relational Expression 3) (R2O + R’O)≥Al2O3, for example, (R2O + R’O)≥(Al2O3 + 1), (R2O + R’O)≥(Al2O3 + 2); and / or (Relational Expression 4) 0.80≤(1 - [(2R2O + 2R’O) / (SiO2+2Al2O3 + 2B2O3)])≤0.93 (wherein, R2O is the sum of the concentrations of one or more alkali metal oxides, and when included in the borosilicate glass composition, R’O is the sum of the concentrations of one or more divalent cation oxides). The composition may contain SiO2, B2O3, one or more alkali metal oxides (R2O), Al2O3, and one or more divalent cation oxides R’O in molar percentages based on oxides that satisfy some (for example, one or more combinations) or all of the above. R2O may be, for example, the sum of Li2O, Na2O, K2O, Rb2O, Cs2O, and R’O may be, for example, the sum of MgO, CaO, SrO, BaO, ZnO. Compositions that satisfy Relational Expressions 1 - 4 described in this paragraph exhibit a unique fracture behavior in which a ring crack is formed around the contact area between the glass and the impact body, and may tend to prevent radial crack propagation. Such fusion - formed glass may also exhibit better chemical durability, scratch resistance, mechanical strength, and optical performance (for example, from the viewpoints of both light transmittance and optical distortion) than other borosilicate glasses. Examples of such glass compositions are given herein.

[0102] Various exemplary compositions of the borosilicate glass contained in the first glass ply 200 will now be described. Examples 1 - 6 are described with respect to the compositions and various properties in Table 1 below.

[0103] [Table 1]

[0104] Additional exemplary borosilicate glass compositions are set forth in Table 2 below.

[0105] [Table 2]

[0106] As shown in Table 2, Examples 12-14 show that an increase in the amount of B2O3 can have the effect of decreasing density. The above examples contain at least 5.5 mol% Na2O+K2O and at least 7.0 mol% Na2O+K2O+MgO+CaO in total. From the examples in Tables 1-2, embodiments of the present disclosure are such that when the total amount of Na2O+K2O+MgO+CaO is at least 7.0 mol%, in particular when there is at least 5.5 mol% Na2O+K2O and at least 1.5 mol% MgO+CaO, the T 200P and liquid phase viscosity for fusion forming are thought to be indicated. Further, embodiments of the present disclosure are such that regardless of the amounts of MgO and CaO, when Na2O+K2O is at least 8 mol%, the T 200P and liquid phase viscosity required for fusion forming are thought to be indicated.

[0107] Referring further to FIG. 3B, the intermediate layer 330 is formed of a suitable material, and the third thickness 335 is selected such that the substrate 30 exhibits desired optical performance attributes (e.g., regarding reflectivity and transmittance) over a suitable wavelength range of interest. In an embodiment, the intermediate layer 330 alone exhibits an average transmittance of 98% or more (e.g., 98.25% or more, 98.5% or more, 98.75% or more, 99.0% or more, 99.25% or more) over a 50 nm wavelength range of interest for light incident normal to the intermediate layer 330. As a result, the substrate, in combination (including no additional laminated film / coating), can exhibit an average transmittance of more than 90% (e.g., 90.25% or more, 90.5% or more, 90.75% or more, 91.0% or more, 91.25% or more) over a 50 nm wavelength range of interest for light incident normal to the first surface 32. Such optical performance is superior to that obtained when using a typical polymer intermediate layer (such as a polyvinyl butyral intermediate layer) for assembling a glass laminate.

[0108] In an embodiment, the intermediate layer 330 is formed of a suitable optically clear adhesive (e.g., a tape-like optically clear adhesive such as 3M™ Optically Clear Adhesive 8146-1 or “3M” Optically Clear Adhesive 8214). In an embodiment, the intermediate layer 330 is formed of a suitable acrylate-based radiation curable resin such as Loctite® AA3491 or Uvekol® S one-component acrylic resin. As described with respect to the examples herein, such materials have been found to exhibit favorable optical performance characteristics over various sensor wavelength ranges of interest (e.g., from 925 nm to 975 nm or from 1525 nm to 1575 nm). Any suitable intermediate layer material that can meet the optical and impact performance criteria described herein may be used. The method of assembling the substrate 30 will vary depending on the type of adhesive used.

[0109] In an embodiment, the third thickness 335 is in the range of 0.05 mm to 1.5 mm, 0.05 mm to 1.4 mm, 0.1 mm to 1.4 mm, 0.1 mm to 1.3 mm, 0.1 mm to 1.2 mm, 0.1 mm to 1.1 mm, 0.1 mm to 1.0 mm, 0.1 mm to 0.95 mm, 0.1 mm to 0.90 mm, 0.1 mm to 0.85 mm, 0.1 mm to 0.80 mm, 0.1 mm to 0.75 mm, 0.1 mm to 0.70 mm, 0.1 mm to 0.65 mm, 0.1 mm to 0.60 mm, 0.1 mm to 0.55 mm, 0.1 mm to 0.50 mm, 0.1 mm to 0.45 mm, 0.1 mm to 0.40 mm, 0.1 mm to 0.35 mm, 0.1 mm to 0.30 mm, 0.1 mm to 0.25 mm, 0.1 mm to 0.20 mm. The thickness can be selected to achieve specific optical properties depending on the intermediate layer material selected.

[0110] The optical properties of the substrate 30 can be adjusted by incorporating different functional layers (e.g., an anti-reflection coating, a decorative coating) or surface treatments (e.g., an anti-glare surface treatment). In an embodiment, for example, the substrate 30 includes a material layer that absorbs visible light and transmits infrared light. Examples of such materials include acrylic sheets that transmit infrared light and absorb visible light, such as those commercially available from ePlastics under the trade names Plexiglas® IR Acrylic 3143 and CYRO’s ACRYLITE® IR Acrylic 1146. “Plexiglas” IR Acrylic 3143 has a transmittance of about 0% (less than at least 10% or less than 1%) for electromagnetic radiation having a wavelength of about 700 nm or less, but has a transmittance of about 90% (more than 85%) for wavelengths in the range of 800 nm to about 1100 nm (including 905 nm).

[0111] In an embodiment, each of the plurality of layers of the substrate 30 exhibits a refractive index in the range of from about 1.40 to about 1.60 (e.g., at the central wavelength of the 50 nm wavelength range of interest described herein). In an embodiment, the substrate exhibits an average transmittance of 95% or more (e.g., 96% or more, 97% or more, 98% or more, 99% or more, 99.5% or more) across the entire 50 nm wavelength range described herein.

[0112] Referring now to FIGS. 4 and 5, each of the first laminated film 36 and the second laminated film 38 includes a number of alternating layers of one or more high refractive index materials 40 and one or more low refractive index materials 42. Although each of the one or more high refractive index materials 40 and the one or more low refractive index materials 42 is identified using the same reference numeral, it should be understood that the use of the same reference numeral does not indicate that each of those layers is made of the same material or has the same structure. In each of the first and second laminated films 36 and 38, different layers of the plurality of layers of the respective high refractive index materials 40 and low refractive index materials 42 can include different compositions or structural characteristics.

[0113] As used herein, the terms "high refractive index material" and "low refractive index material" refer to the values of the refractive indices relative to each other, and the refractive index of one or more high refractive index materials 40 is greater than the refractive index of one or more low refractive index materials 42. In embodiments, one or more high refractive index materials 40 have a refractive index of from about 1.7 to about 4.0. In embodiments, one or more low refractive index materials 42 have a refractive index of from about 1.3 to about 1.6. In embodiments, one or more low refractive index materials 42 have a refractive index of from about 1.3 to about 1.7, while one or more high refractive index materials 40 have a refractive index of from about 1.9 to about 3.8. The difference in refractive index between any of the one or more high refractive index materials 40 and any of the one or more low refractive index materials 42 can be about 0.1 or more, 0.2 or more, 0.3 or more, 0.4 or more, 0.5 or more, 0.6 or more, 0.7 or more, 0.8 or more, 0.9 or more, 1.0 or more, 1.5 or more, 2.0 or more, 2.1 or more, 2.2 or more, or even 2.3 or more. Due to the difference in refractive index between the one or more high refractive index materials 40 and the one or more low refractive index materials 42, by manipulating the number and thickness of the alternating layers, selective transmission of electromagnetic radiation within the wavelength range passing through the window 24, and separately, selective reflection of electromagnetic radiation within the wavelength range from the first laminated film 36 can be enabled. The first laminated film 36 (and, when utilized, the second laminated film 38) is, therefore, a thin film optical filter having predetermined optical properties determined as a function of the number, thickness, number, and materials selected as the one or more high refractive index materials 40 and the one or more low refractive index materials 42.

[0114] Some examples of materials suitable for use as one or more low refractive index materials 42 include SiO2, Al2O3, GeO2, SiO, AlO x N y 、SiO x N y 、Si u Al v O x N y, MgO, MgAl2O4, MgF2, BaF2, CaF2, DyF3, YbF3, YF3, and CeF3. The nitrogen content of the materials used for one or more low refractive index materials 42 may be minimal (e.g., in materials such as AlO x N y , SiO x N y , and Si u Al v O x N y ).

[0115] Some examples of materials suitable for use as one or more high refractive index materials 40 include Si, amorphous silicon (a-Si), SiN x , SiN x :H y , AlN x , Si u Al v O x N y , Ta2O5, Nb2O5, AlN, Si3N4, AlO x N y , SiO x N y , HfO2, TiO2, ZrO2, Y2O3, Al2O3, MoO3, and diamond-like carbon. The oxygen content of the materials of the high refractive index material 40 can be minimized, especially in the SiN x or AlN x materials. The AlO x N y materials can be considered as oxygen-doped AlN y , that is, they can have an AlN y crystal structure (e.g., wurtzite), and do not necessarily have an AlON crystal structure. Exemplary preferred AlO x N y materials used as one or more high refractive index materials 40 may contain from about 0 atomic % to about 20 atomic % oxygen, or from about 5 atomic % to about 15 atomic % oxygen, but contain from about 30 atomic % to about 50 atomic % nitrogen. Exemplary preferred Si u Al v O x Ny may contain from about 10 atomic % to about 30 atomic % or from about 15 atomic % to about 25 atomic % of silicon, from about 20 atomic % to about 40 atomic % or from about 25 atomic % to about 35 atomic % of aluminum, from about 0 atomic % to about 20 atomic % or from about 1 atomic % to about 20 atomic % of oxygen, and from about 30 atomic % to about 50 atomic % of nitrogen. The foregoing materials may be hydrogenated up to about 30 mass %. Since the refractive indices of the one or more high refractive index materials 40 and the one or more low refractive index materials 42 are relative to each other, the same material (such as Al2O3) may be suitable for the one or more high refractive index materials 40 depending on the refractive index of the material selected for the one or more low refractive index materials 42, or may be suitable for the one or more low refractive index materials 42 depending on the refractive index of the material selected for the one or more high refractive index materials 40.

[0116] In an embodiment, the one or more low refractive index materials 42 of the first layered film 36 consist of a layer of SiO2, and the one or more high refractive index materials 40 of the first layered film 36 are SiO x N y or SiN x and consist of a layer of. In an embodiment, the one or more low refractive index materials 42 of the first layered film 36 consist of a layer of SiO2, and the one or more high refractive index materials 40 of the first layered film 36 are SiN x or SiO x N y and consist of a layer of Si (for example, a-Si), while the one or more low refractive index materials 42 of the second layered film 38 consist of a layer of SiO2, and the one or more high refractive index materials 40 of the second layered film 38 are SiN x or SiO x N y and consist of a layer of Si (for example, a-Si).

[0117] The number of alternating layers of the high refractive index material 40 and the low refractive index material 42 in the first laminated film 36 or the second laminated film 38 is not particularly limited. In an embodiment, the number of alternating layers in the first laminated film 36 is 7 or more, 9 or more, 11 or more, 13 or more, 15 or more, 17 or more, 19 or more, 21 or more, 23 or more, 25 or more, or 51 or more, or 81 or more. In an embodiment, the number of alternating layers in the second laminated film 38 is 7 or more, 9 or more, 11 or more, 13 or more, 15 or more, 17 or more, 19 or more, 21 or more, 23 or more, 25 or more, or 51 or more, or 81 or more. In an embodiment, the number of alternating layers in the first laminated film 36 and the second laminated film 38 that jointly form the window 24, excluding the substrate 30, is 14 or more, 20 or more, 26 or more, 32 or more, 38 or more, 44 or more, 50 or more, 72 or more, or 100 or more. Generally, the greater the number of layers in the first laminated film 36 and the second laminated film 38, the more narrowly the transmittance and reflectance characteristics of the window 24 are adjusted for one or more specific wavelengths or wavelength ranges.

[0118] Each of the alternating layers of the first laminated film 36 and the second laminated film 38 has a thickness. The selected thickness of each of the alternating layers determines the optical path length of the light propagating through the window 24 and the constructive and destructive interference between the different light rays reflected at the interfaces of the respective materials of the window 24. Accordingly, the thickness of each of the alternating layers, in combination with the refractive indices of one or more high refractive index materials 40 and one or more low refractive index materials 42, determines the reflectance spectrum and the transmittance spectrum of the window 24.

[0119] Referring to FIGS. 3A, 3B, 4, and 5, the reflected radiation 28 first reaches the end face 44 of the first laminated film 36 when interacting with the window 24, and the end face 44 is open to the external environment 26. In certain embodiments, a layer of one or more low refractive index materials 42 more closely matches the refractive index of the air in the external environment 26, and thus provides the end face 44 to reduce the reflection of incident electromagnetic radiation (whether reflected radiation 28 or otherwise) at the end face 44. That layer of one or more low refractive index materials 42 providing the end face 44 is the layer of the first laminated film 36 furthest from the substrate 30. Similarly, in embodiments where the one or more low refractive index materials 42 are SiO2, a layer of SiO2 as the one or more low refractive index materials 42 is disposed directly on the first surface 32 of the substrate 30. This substrate 30 will typically be made of a large mole percentage of SiO2. Without intending to be bound by theory, it is believed that the common feature of SiO2 in both the substrate 30 and the adjacent layer of one or more low refractive index materials 42 increases the adhesion strength.

[0120] The emitted radiation 22 first reaches the end face 48 of the second laminated film 38 when interacting with the window 24. In certain embodiments, a layer of one or more low refractive index materials 42 more closely matches the refractive index of the air within the enclosure 20, and thus provides the end face 48 to reduce the reflection of the emitted radiation 22 at the end face 48. That layer of one or more low refractive index materials 42 providing the end face 48 is the layer of the second laminated film 38 furthest from the substrate 30. Similarly, in embodiments where the one or more low refractive index materials 42 are SiO2, a layer of SiO2 as the one or more low refractive index materials 42 is disposed directly on the second surface 34 of the substrate 30.

[0121] Materials having a relatively high refractive index can simultaneously have a relatively high hardness that provides scratch resistance and impact resistance. Examples of materials that can be one of the one or more high refractive index materials 40 while having a high hardness include SiO x N y There is. Examples of other materials that can be the high refractive index material 40 while having a high hardness include SiN x, SiN x :H y , and there is Si3N4. SiO x N y A relatively thick (e.g., 500 nm or more) layer of N (or other suitable high refractive index material) has been found to increase the scratch resistance and / or damage resistance of window 24. Such increased scratch resistance and / or damage resistance would be particularly beneficial in the first layer film 36, which would be likely to collide with debris from the external environment 26. Thus, in an embodiment, the first layer film 36 includes a layer of one of the one or more high refractive index materials 40 having a thickness of 500 nm or more (e.g., 1000 nm or more, 1500 nm or more, 2000 nm or more). Such a high refractive index material with a thickness of 500 nm or more is described herein as a "scratch resistant layer".

[0122] In an embodiment, the thickness of the scratch resistant layer and its position within the first layer film 36 can be optimized to provide the first layer film 36, and thus the window 24 as a whole, with a desired level of hardness and scratch resistance. For different applications of window 24, the desired thickness of the scratch resistant layer of the high refractive index material 40 that functions as a layer providing hardness and scratch resistance to window 24 may vary. For example, for a window 24 protecting the LIDAR system 12 on the vehicle 10, a different thickness of the scratch resistant layer of the high refractive index material 40 may be required than for a window 24 protecting the LIDAR system 12 in an office building. In an embodiment, the scratch resistant layer of the high refractive index material 40 that functions as a layer providing hardness and scratch resistance to window 24 has a thickness between 500 nm and 50000 nm, e.g., between 500 nm and 10000 nm, e.g., between 2000 nm and 5000 nm. In an embodiment, the thickness of this scratch resistant layer of the high refractive index material 40 is 50% or more, 65% or more, or 85% or more, or 86% or more of the thickness of the first layer film 36. Generally, the scratch resistant layer of the high refractive index material 40 that functions as a layer providing hardness and scratch resistance to window 24 will be the portion of the first layer film 36 facing the external environment 26 rather than the second layer film 38 protected by the enclosure 20, although it need not necessarily be so.

[0123] As further detailed below, the quantity, thickness, number, and materials of the remaining layers of the first laminated film 36 and the second laminated film 38 can be set to provide the window 24 with desired optical properties (transmittance and reflectance at a desired wavelength), regardless of the thickness selected for the scratch-resistant layer of the high refractive index material 40 that functions as a layer providing hardness and scratch resistance to the window 24. The optical properties of the window 24 as a whole are thus insensitive to the thickness of the scratch-resistant layer of the high refractive index material 40 that functions as a layer providing hardness and scratch resistance to the window 24 because the material has relatively little or negligible optical absorption of electromagnetic radiation in the target wavelength or wavelength range (e.g., from 1400 nm to 1600 nm, 1550 nm). For example, Si3N4 absorbs only negligibly electromagnetic radiation in the wavelength range from 700 nm to 2000 nm.

[0124] Due to this overall insensitivity, the scratch-resistant layer of the high refractive index material 40 within the first laminated film 36 can have a predetermined thickness to meet the specified hardness or scratch resistance requirements. For example, the first laminated film 36 for the window 24 used on the roof 14 of the vehicle 10 may have different hardness and scratch resistance requirements than the first laminated film 36 for the window 24 used on the front portion 16 of the vehicle 10, and thus, the thickness of the scratch-resistant layer of the high refractive index material 40 will be different. This can be achieved without significantly changing the transmittance and reflectance characteristics of the first laminated film 36 as a whole.

[0125] The hardness of the first laminated film 36, and thus the window 24, including the scratch-resistant layer of the high refractive index material 40, can be quantified. In an embodiment, the maximum hardness of the window 24, measured with a Berkovich indenter hardness test on the first laminated film 36 having the scratch-resistant layer of the high refractive index material 40, is about 8 GPa or more, about 10 GPa or more, about 12 GPa or more, about 14 GPa or more, about 15 GPa or more, about 16 GPa or more, or about 18 GPa or more at one or more indentation depths from 50 nm to 2000 nm (measured from the end face 44), and further from 2000 nm to 5000 nm. As used herein, the "Berkovich indenter hardness test" includes the step of measuring the hardness of the material on the surface by pressing a diamond Berkovich indenter into the surface. The Berkovich indenter hardness test involves pressing a diamond Berkovich indenter into the end face 44 of the first laminated film 36 to form an indentation up to an indentation depth in the range of about 50 nm to 2000 nm (or the total thickness of the first laminated film 36), and generally measuring the maximum hardness from this indentation along the entire indentation depth range or a part of this indentation depth range (e.g., in the range from about 100 nm to about 600 nm) using the methods described in Oliver, W. C.; Pharr, G. M. An improved technique for determining hardness and elastic modulus using load and displacement sensing indentation experiments. J. Mater. Res., Vol. 7, No. 6, 1992, 1564-1583, and Oliver, W. C.; Pharr, G. M. Measurement of Hardness and Elastic Modulus by Instrument Indentation: Advances in Understanding and Refinements to Methodology. J. Mater. Res., Vol. 19, No. 1, 2004, 3-20.These levels of hardness improve the resistance of the window 24 to impact damage from sand, gravel, debris, and other objects that the LIDAR system 12 encounters while being used for its intended purpose as related to the vehicle 10 (see FIG. 1). Thus, these levels of hardness reduce or prevent the light scattering and performance degradation of the LIDAR system 12 that would otherwise occur due to such impact damage.

[0126] In an embodiment, at least a portion of the first laminated film 36 is disposed between the scratch-resistant layer of the high refractive index material 40 and the end face 44. In an embodiment, the first laminated film 36 includes a plurality of alternating layers of one or more low refractive index materials 42 and one or more high refractive index materials 40 between the end face 44 and the scratch-resistant layer. A laminate of such alternating layers disposed between the scratch-resistant layer and the end face 44 is described herein as an "optical control layer". In an embodiment, the optical control layer disposed between the scratch-resistant layer and the end face 44 has a total thickness of 500 nm or more (e.g., 600 nm or more, 700 nm or more, 800 nm or more, 800 nm or more, 1000 nm or more, 1100 nm or more, 1200 nm or more, 1300 nm or more). The number, composition, and thickness of the optical control layer can be selected to provide the desired anti-reflection performance attributes described herein at the operating wavelength of the LIDAR system 12 between 1400 nm and 1600 nm. In that way, the second laminated film 38 can be designed to provide the desired optical performance characteristics in the visible and / or ultraviolet spectrum as described herein.

[0127] In an embodiment, at least 25% (e.g., at least 26%, at least 27%, at least 28%, at least 29%, at least 30%) of the thickness 46 of the first laminated film 36 is disposed between the scratch-resistant layer and the end face 44. Such a depth of the scratch-resistant layer within the first laminated film 36 is thought to promote the first laminated film 36 having a relatively high nanoindentation hardness (measured by a Berkovich indenter hardness test) over a relatively large range of depths within the first laminated film 36. In an embodiment, the first laminated film 36 has a nanoindentation hardness of 8 GPa or more from a depth of 250 nm to a depth of 2000 nm within the first laminated film 36. In an embodiment, the first laminated film 36 has a nanoindentation hardness of 8.5 GPa or more from a depth of 1000 nm to a depth of 2000 nm within the first laminated film 36. Such hardness values promote imparting scratch resistance and / or damage resistance to scratches having a relatively wide range of depths.

[0128] Referring now to FIGS. 4 and 5, the first laminated film 36 has a thickness 46 and the second laminated film 38 has a thickness 50. The thickness 46 of the first laminated film 36, which is considered to include a scratch-resistant layer of one or more high refractive index materials 40, is at least about 1 μm and yet can provide the transmittance and reflectance characteristics described herein. In an embodiment, the thickness 46 is in the range of 1 μm to greater than 50 μm, including from about 1 μm to about 10 μm and from about 2800 nm to about 5900 nm. The lower limit of about 1 μm is approximately the minimum value of the thickness 46 that still gives the window 24 hardness and scratch resistance. The upper limit of the thickness 46 is limited by the time and cost required to dispose a layer of the first laminated film 36 on the substrate 30. In addition, the upper limit of the thickness 46 is limited to prevent the first laminated film 36 from distorting the substrate 30 (depending on the thickness of the substrate 30). The thickness 50 of the second laminated film 38 can be any thickness that is considered necessary to give the window 24 the desired transmittance and reflectance properties. In an embodiment, the thickness 50 of the second laminated film 38 is in the range of about 800 nm to about 7000 nm.

[0129] By giving the window 24 hardness, impact resistance, and scratch resistance according to the maximum thickness of the high refractive index material 40, while solving the problems described in the problems to be solved by the invention, the quantity, thickness, number, and material of the layers of the first laminated film 36 and the second laminated film 38 are also set to provide a relatively high transmittance of infrared radiation in an appropriate 50 nm wavelength range related to the sensor system. In an embodiment, the quantity, thickness, number, and material of the layers of the first laminated film 36 and the second laminated film 38 are such that the window 24 has an average transmittance of 95% or more (for example, 95.5% or more, 96.0% or more, 96.5% or more, 97.0% or more, 97.5% or more, 98% or more, 98.5% or more, 99% or more, 99.5% or more) over a 50 nm wavelength range of interest included in the wavelength range of 800 nm to 1800 nm for light normally incident on the window 24. In an embodiment, the quantity, thickness, number, and material of the layers of the first laminated film 36 and the second laminated film 38 are such that the window 24 has an average reflectance of 5.0% or less (for example, 4.5% or less, 4.0% or less, 3.5% or less, 3.0% or less, 2.5% or less, 2.0% or less, 1.5% or less, 1.0% or less, 0.5% or less).

[0130] The specific structures of the first and second laminated films 36 and 38 can vary depending on the wavelength range of interest. For example, in an embodiment, the first and second laminated films 36 and 38 can be structured for a 50 nm wavelength range including a central wavelength of about 905 nm. In such an embodiment, the first and second laminated films can generally have the structure described in International Publication No. WO 2020 / 247245, filed on May 29, 2020, entitled "Hardened Optical Windows for LiDAR Applications at 850 - 950 nm", which is incorporated herein by reference in its entirety.

[0131] In an embodiment, the first and second layered films 36 and 38 can be structured for a wavelength range of 50 nm including a center wavelength of about 1550 nm. In such an embodiment, the first and second layered films can generally have the structure described in International Publication No. WO 2020 / 247292, filed on June 1, 2020, titled "Hardened Optical Windows with Anti-Reflective, Reflective, and Absorbing Layers for Infrared Sensing Systems", which is incorporated herein by reference in its entirety. In such an embodiment, the quantity, thickness, number, and materials of the first layered film 36 and the second layered film 38 can be set such that the window 24 has an average reflectance of less than 10% for electromagnetic radiation having a wavelength of 1550 nm at any angle of incidence within the range of 0° to 8°.

[0132] The design of the first layered film 36 and the second layered film 38 can provide additional performance attributes (e.g., optical performance outside the wavelength range of interest related to the sensor, appearance) to the window 24. For example, in an embodiment, the first and second layered films 36 and 38 can be set such that the window 24 exhibits a black or opaque appearance when viewed from the end face 44 and relatively low transmittance and reflectance across the visible spectrum. In such an embodiment, the first and second layered films 36 and 38 can be structured as described in U.S. Provisional Patent Application No. 63 / 344,147, filed on May 20, 2022, titled "Hardened Optical Windows with Anti-Reflective Films Having Low Visible Reflectance and Transmission for Infrared Sensing system", which is incorporated herein by reference in its entirety.

[0133] In such an embodiment, the thickness, number, and material of the alternating layers of the first and second layer films 36 and 38 are such that the window 24 has an average reflectance of 0.5% or less (e.g., 0.4% or less, 0.3% or less, 0.2% or less, 0.1% or less, 0.08% or less) over a 50 nm wavelength range of interest from 1400 nm to 1600 nm for light incident on the first and second surfaces 32 and 34 at an angle within 15° of the normal to the first and second surfaces 32 and 34. In addition, in such an embodiment, the thickness, number, and material of the alternating layers of the first and second layer films 36 and 38 are such that the window has an average P-polarized transmittance and an average S-polarized transmittance of greater than 85% (e.g., 86% or more, 87% or more, 88% or more, 89% or more, 90% or more, 91% or more, 92% or more) over a 50 nm wavelength range of interest from 1400 nm to 1600 nm for light incident on the first and second surfaces 32 and 34 at an angle within 60° of the normal to the first and second surfaces 32 and 34 (e.g., at an incident angle from 0° to 60°, 0° to 50°, 0° to 40°, 0° to 30°). In addition, in such an embodiment, when viewed from the external environment 26 (see FIG. 2), the window 24 can exhibit an a * value and a b * value in the CIELAB color space that are -6.0 or greater and 6.0 or less for light having an incident angle on the first surface 32 ranging from 0° to 90°. Such color space values can be obtained even in embodiments where the substrate 30 has a relatively high transmittance (e.g., greater than 90%) and a relatively low reflectance (e.g., 22% or less) over the entire visible spectrum. The thickness, number, and material of the alternating layers of the first and second layer films 36 and 38 are set such that the window 24 has a CIELAB lightness L * value of less than 45 (e.g., 40 or less, 35 or less, 30 or less) when viewed at an incident angle of 60° or less.

[0134] In an embodiment, the first and second layered films 36 and 38 are fabricated such that the window 24 exhibits a transparent appearance when viewed from the end face 44. In such an embodiment, the first layered film 36 and the second layered film 38 can be structured as described in U.S. Provisional Patent Application No. 63 / 289828, filed on December 15, 2021, entitled "Hardened Optical Windows with Anti-Reflective Films Having Low Reflectance and High Transmission in Multiple Spectral Ranges", which is hereby incorporated by reference in its entirety. In such an embodiment, the thicknesses and materials of the alternating layers of the first and second layered films 36 and 38 are set such that the window 24 has an average transmittance of 70% or more (e.g., 80% or more, 85% or more) for light within the visible spectrum incident on the first face 32 or the second face at an incident angle of 60° or less. For example, when viewed from the external environment 26 (see FIG. 1), the window 24 has an a * value and a b * value in the CIELAB color space that is -6.0 or more and 6.0 or less for light having an incident angle on the first face 32 ranging from 0° to 90°. Such color space values can be obtained even in embodiments where the substrate 30 has a relatively high transmittance (e.g., greater than 90%) and a relatively low reflectance (e.g., 22% or less) across the entire visible spectrum. In such an embodiment, the number, thickness, and materials of the alternating layers of the first and second layered films 36 and 38 are such that the window 24 has an average P-polarized transmittance and an average S-polarized transmittance greater than 85% (e.g., 86% or more, 87% or more, 88% or more, 89% or more, 90% or more) calculated over a 50-nm wavelength range of interest from 1400 nm to 1600 nm for light incident on the first face 32 and the second face at an angle within 60° of the normal of the first face 32 and the second face (e.g., at an incident angle from 0° to 60°, 0° to 50°, 0° to 40°, 0° to 30°).

[0135] In an embodiment, one or more of the first layered film 36 and the second layered film 38 can include one or more transparent conductive oxide layers such that the window 24 exhibits at least 15 dB of microwave energy attenuation for radiation above 1 GHz. Alternatively, or in addition, in such an embodiment, the second layered film 38 can include one or more absorption layers that are not in direct contact with the substrate 30. Such absorption layers may not be present in the first layered film 36. In such an embodiment, the first and second layered films 36 and 38 can be fabricated as described in U.S. Provisional Patent Application No. 63 / 284,161, filed November 30, 2021, entitled "Durable Optical Windows for LiDAR Applications", which is hereby incorporated by reference in its entirety.

[0136] The layers of the first layered film 36 and the second layered film 38 (i.e., the layers of the high refractive index material 40 and the low refractive index material 42) may be formed by any method known in the art, including an individual deposition process or a continuous deposition process. In one or more embodiments, the layers may be formed using only a continuous deposition process or only an individual deposition process.

Examples

[0137] Exemplary first and second layered films - An exemplary combination of layered films considered suitable for use in the asymmetric laminate structure described herein is given in Table 3 below. In the examples, the first layered film 36 is SiO2 as the low refractive index material 42 and SiN as the high refractive index material 40 xIt included 12 alternating layers of a-Si. Layers 7 and 5 of the first laminated film 36 were formed from silicon in order to absorb the visible spectrum and eliminate the layers necessary to achieve desirable performance in the infrared. Layers 7 and 5 were also adjacent to other layers of high refractive index material (for example, layers 7 and 8 formed a composite high refractive index layer, and layers 4 and 5 formed another composite high refractive index layer). Layer 4 was an abrasion-resistant layer of high refractive index material 40 with a thickness of 2000 nm. Therefore, this abrasion-resistant layer was adjacent to the silicon layer to provide a relatively thick layer of high refractive index material. In this example, the abrasion-resistant layer constituted 48% of the thickness of the first laminated film 36.

[0138] The second laminated film 38 included 7 alternating layers of low refractive index material 42 and high refractive index material 40. In this example, the low refractive index material 42 was SiO2, while the high refractive index material 40 was SiN x and a-Si. The low refractive index material closest to the substrate 30 was formed from Si in order to absorb the visible spectrum and reduce the number of layers necessary to achieve desirable performance in the infrared.

[0139] The layer thicknesses of the first laminated film 36 and the second laminated film 38 were set as described in Table 3 below.

[0140]

Table 3

[0141] In another example, an asymmetric laminate structure 300 was used for the substrate 30. The first glass ply 200 was made from a 3.8 mm thick borosilicate glass sheet (one of the glasses described in the international patent application No. PCT / US2021 / 61966 filed on December 6, 2021), the intermediate layer 330 made from an optically transparent adhesive had a thickness of 0.1 mm, and the second glass ply 320 was a 0.7 mm thick aluminosilicate glass sheet. In this example, only the first laminated film 36 was included.

[0142] Ball bearing impact tests were performed on various laminate boards that can be used as the substrate 30. The first exemplary substrate was a 5.0 mm thick monolithic layer of an existing borosilicate glass composition. The second exemplary substrate was an asymmetric laminate structure 300 where the first glass ply was a 2.85 mm thick layer of unstrengthened aluminosilicate glass, the intermediate layer 330 was a 100 μm thick layer of an optically transparent adhesive, and the second glass ply 320 was a 0.55 mm thick layer of unstrengthened aluminosilicate glass. The third exemplary substrate was an asymmetric laminate structure 300 where the first glass ply was a 2.85 mm thick layer of unstrengthened aluminosilicate glass, the intermediate layer 330 was a 100 μm thick layer of an optically transparent adhesive, and the second glass ply 320 was a 1.1 mm thick layer of chemically strengthened aluminosilicate glass. A 1 g ball bearing was fired at the sample at an incident angle of 45° onto the first glass ply 200 (uncoated in this test). Figure 6A shows the results of a collision with the first exemplary substrate at 80.47 km / h. As can be seen from the figure, despite the increased thickness, conical cracks penetrated the entire substrate, which would compromise the hermeticity. Figure 6B shows the results of a collision with the second exemplary substrate at 160.93 km / h. As can be seen from the figure, holes were formed in the laminate board, which would compromise the hermeticity. Figure 6C shows the results of a collision with the third exemplary substrate at 160.93 km / h. As can be seen from the figure, the first glass ply 200 was broken, but the second glass ply 320 remained undamaged, thus maintaining the hermeticity. From these results, it is shown that the asymmetric laminate structure described herein can provide excellent impact performance superior to that of monolithic windows, even when the total thickness is small.

[0143] The first glass ply 200 was a 2.85 mm thick non-reinforced aluminosilicate glass, the intermediate layer 330 was a 760 μm thick acrylic resin (“Uvekol” S15), and the second glass ply 320 was a 0.55 mm thick ion-exchanged reinforced aluminosilicate glass sheet (low CT-CT10). An asymmetric laminate structure 300 was subjected to a Gravelometer test according to ASTM D3170. After two rounds of multiple impact tests, the hermeticity was maintained. Dents and some cracks were observed on the first glass ply 200, but the second glass ply 320 was not damaged enough to maintain the hermeticity. Monolithic panels of the same thickness could not maintain the hermeticity when similar tests were conducted.

[0144] The light transmittance was measured for four candidate materials for the intermediate layer: (a) “3M” Optically Clear Adhesive 8146-1; (b) “3M” Optically Clear Adhesive 8214; (c) “Loctite” AA3491; and (d) “Uvekol” one-component acrylic resin. The results are shown in Figure 7. For the individual intermediate layers, the transmittance spectra between 1520 nm and 1580 nm are shown. The goal is for the transmittance of the laminate (without coating) to be over 91% (preferably over 92%), and 98% or more (preferably 99% or more). As can be seen from the figure, each of the intermediate layers showed a transmittance of 98% or more from the beginning to the end of the illustrated wavelength range. The optically clear adhesives showed a transmittance of over 99% at 1550 nm. These results indicate that these intermediate layer materials are suitable for the wavelength ranges mentioned.

[0145] The asymmetric laminate structure 300, where the first glass ply 200 was a 2.85 mm thick layer of non-reinforced aluminosilicate glass, the intermediate layer 330 was 0.1 mm thick, and the second glass ply 320 was a 0.55 mm thick layer of chemically strengthened aluminosilicate, was constructed with each of the intermediate layer materials described with respect to Figure 7. The results are shown in Table 4 below. T 可視 、R 前面(Reflectance at the first major surface 202), and R 背面 All of (reflectance at the fourth major surface 334) are averages over the wavelength range from 380 nm to 780 nm. T 940 And T 1550 Are the transmittances at wavelengths of 940 nm and 1550 nm, respectively. All values are percentages and were measured at normal incidence.

[0146]

Table 4

[0147] When at least one of the first and second laminated films 36 and 38 described in this specification is present (such as in the examples of Table 4), the transmittance value is considered to increase by at least 6% and the reflectance value to decrease by at least 6% (when the second laminated film 38 is provided). Thus, from the previous results, it is shown that the coated laminate according to the present disclosure can exhibit an average transmittance of at least 95% over a 50 nm wavelength range of interest included in the wavelength range from 800 nm to 1800 nm, and an average reflectance in this 50 nm wavelength range of less than 5%.

[0148] It will be apparent to those skilled in the art that various modifications and changes can be made without departing from the spirit or scope of the claims.

[0149] Hereinafter, preferred embodiments of the present invention will be described item by item.

[0150] Embodiment 1 In a window for a detection system, A first glass ply having a first major surface, a second major surface opposite the first major surface, and a first thickness extending between the first major surface and the second major surface, A second glass ply having a third major surface, a fourth major surface opposite the third major surface, and a second thickness extending between the third major surface and the fourth major surface, An intermediate layer disposed between the first glass ply and the second glass ply, bonding the second major surface to the third major surface, and One or more laminated films disposed on at least one of the first major surface and the fourth major surface, each laminated film comprising alternating layers of one or more high refractive index materials and one or more low refractive index materials. Comprising The intermediate layer alone has an average transmittance of greater than 98% over a 50 nm wavelength range of interest for light normally incident on the fourth major surface or the first major surface. The 50 nm wavelength range of interest is included in the wavelength range from 800 nm to 1800 nm. The alternating layers of the one or more laminated films are configured to exhibit an average transmittance of 95% or more over the 50 nm wavelength range of interest for light normally incident on the first major surface or the fourth major surface of the window. The alternating layers of the one or more laminated films are configured to exhibit an average reflectance of 5% or less over the 50 nm wavelength range of interest for light normally incident on the first major surface or the fourth major surface of the window. The first thickness is at least twice as thick as the second thickness. The second glass ply is strengthened to a greater extent than the first glass ply such that the second glass ply exhibits a central tension greater than the central tension of the central region of the first glass ply, a window.

[0151] Embodiment 2 The window according to Embodiment 1, wherein the first glass ply is not strengthened.

[0152] Embodiment 3 The first thickness is 2.0 mm or more and 8.0 mm or less. The window according to Embodiment 1 or 2, wherein the second thickness is 0.1 mm or more and 1.2 mm or less.

[0153] Embodiment 4 The window according to any one of Embodiments 1 to 3, wherein both the first glass ply and the second glass ply are formed from aluminosilicate glass.

[0154] Embodiment 5 The window according to any one of Embodiments 1 to 3, wherein the first glass ply is formed of glass that exhibits specific fracture behavior when a Vickers indenter test is performed.

[0155] Embodiment 6 The window according to Embodiment 5, wherein the first glass ply is made of a borosilicate glass composition.

[0156] Embodiment 7 Regarding the constituent oxides, the borosilicate glass composition is SiO2, B2O3, Al2O3, one or more alkali metal oxides, and one or more divalent cation oxides selected from the group consisting of MgO, CaO, SrO, BaO, and ZnO, 11 mol% or more and 16 mol% or less of B2O3, 2 mol% or more and 6 mol% or less of Al2O3, and a total of 7.0 mol% or more of Na2O, K2O, MgO, and CaO, and includes the concentrations of the oxide-based molar percentages of SiO2, B2O3, the one or more alkali metal oxides, Al2O3, and the one or more alkaline earth metal oxides satisfy the relational expressions: (R2O + R’O) ≧ Al2O3, 0.80 < (1 - [(2R2O + 2R’O) / (SiO2 + 2Al2O3 + 2B2O3)]) < 0.93 wherein, R2O is the total of the concentrations of the one or more alkali metal oxides, and R’O is the total of the concentrations of the one or more alkaline earth metal oxides. The window according to Embodiment 6.

[0157] Embodiment 8 The window according to any one of Embodiments 1 to 7, wherein the first thickness is at least three times thicker than the second thickness.

[0158] Embodiment 9 ​The window according to any one of Embodiments 1 to 8, wherein the second glass ply is chemically strengthened so as to have a surface compressive stress on the fourth major surface of 250 MPa or more and 900 MPa or less.

[0159] Embodiment 10 The window according to Embodiment 9, wherein when the first glass ply collides with a 1 g ball bearing moving at 160.93 km / h, cracks that penetrate all of the second thickness are not formed.

[0160] Embodiment 11 The window according to any one of Embodiments 1 to 10, wherein the intermediate layer is made of an optically transparent adhesive or an ultraviolet curable acrylic resin.

[0161] Embodiment 12 The window according to Embodiment 11, wherein the intermediate layer has a third thickness of 0.05 mm or more and 1.0 mm or less.

[0162] Embodiment 13 The window according to any one of Embodiments 1 to 12, wherein the wavelength range of interest of 50 nm is centered at a wavelength between 900 nm and 950 nm.

[0163] Embodiment 14 The window according to any one of Embodiments 1 to 12, wherein the wavelength range of interest of 50 nm is centered at a wavelength between 1525 nm and 1575 nm.

[0164] Embodiment 15 The one or more laminated films include a first laminated film disposed on the first major surface. The window according to any one of Embodiments 1 to 14, wherein the window has a maximum hardness of at least 8 GPa as measured by a Berkovich indenter hardness test on the first laminated film.

[0165] Embodiment 16 The one or more laminated films include a second laminated film disposed on the fourth major surface. The quantity, thickness, number, and material of the alternating layers of the first and second layer films are such that the window has, for light incident on the first major surface and the second major surface at an angle of 15° or less, an average reflectance calculated over the 50 nm wavelength range of interest between 1400 nm and 1600 nm of less than 0.5%, a CIELAB L value of 45 or less for an incident angle of 60° or less on the first layer film, and * and a CIELAB a value of -6.0 or more and 6.0 or less and a CIELAB b value of -6.0 or more and 6.0 or less when viewed from the side of the first layer film, * and b * values, the window according to Embodiment 15, which is configured to have.

[0166] Embodiment 17 One of the alternating layers of the first layer film farthest from the first major surface forms the end face material of the window, and the end face material of the window is made of a low refractive index material, the window according to Embodiment 16, wherein the first layer film is formed from one of the one or more high refractive index materials and includes a scratch-resistant layer having a thickness of 1500 nm or more and 5000 nm or less.

[0167] Embodiment 18 The scratch-resistant layer is separated from the end face by a plurality of layers among the alternating layers of the one or more low refractive index materials and the one or more high refractive index materials of the first layer film, the window according to Embodiment 17, wherein the scratch-resistant layer is separated from the end face by at least 1000 nm.

[0168] Embodiment 19 The one or more layer films include a second layer film disposed on the fourth major surface, the quantity, thickness, and material of the alternating layers of the first and second layer films are such that the window has, For light incident on the first main surface and the second main surface at an incident angle of 15° or less, an average transmittance calculated over the wavelength range of 50 nm of interest, which is more than 90%, For light incident on the first main surface and the second main surface at an angle of 15° or less, an average reflectance calculated over the wavelength range of 50 nm of interest, which is less than 0.5%, and For light incident on the first main surface and the second main surface at an incident angle of 15° or less, an average transmittance calculated from 400 nm to 700 nm, which is more than 80%, The window according to Embodiment 15, which is configured to have

[0169] Embodiment 20 In a window for a detection system, A first glass ply having a first main surface, a second main surface opposite the first main surface, and a first thickness extending between the first main surface and the second main surface, A second glass ply having a third main surface, a fourth main surface opposite the third main surface, and a second thickness extending between the third main surface and the fourth main surface, An intermediate layer disposed between the first glass ply and the second glass ply, coupling the second main surface to the third main surface, and One or more laminated films disposed on at least one of the first main surface and the fourth main surface, each comprising one or more alternating layers of a high refractive index material and one or more low refractive index materials, Comprising Excluding the one or more laminated films, the first glass ply, the second glass ply, and the intermediate layer, in combination, have an average transmittance of more than 90% over the wavelength range of 50 nm of interest, The wavelength range of 50 nm of interest is included in the wavelength range from 800 nm to 1800 nm, The alternating layers of the one or more laminated films are configured to exhibit an average transmittance of 95% or more over the wavelength range of 50 nm of interest for light incident normally on the first main surface or the fourth main surface of the window, The alternating layers of the one or more laminated films are configured to exhibit an average reflectance of 5% or less over the wavelength range of 50 nm of interest for light incident normally on the window on the first major surface or the fourth major surface. The first thickness is at least twice as thick as the second thickness. The second glass ply is reinforced to a greater extent than the first glass ply such that the second glass ply exhibits a central tension greater than the central tension of the central region of the first glass ply, window.

[0170] Embodiment 21 The window according to embodiment 20, wherein the first glass ply is not reinforced.

[0171] Embodiment 22 The first thickness is 2.0 mm or more and 8.0 mm or less. The window according to embodiment 20 or 21, wherein the second thickness is 0.1 mm or more and 1.2 mm or less.

[0172] Embodiment 23 The window according to any one of embodiments 20 to 22, wherein both the first glass ply and the second glass ply are formed from aluminosilicate glass.

[0173] Embodiment 24 The window according to any one of embodiments 20 to 23, wherein the first glass ply is formed from glass that exhibits specific fracture behavior when a Vickers indenter test is performed.

[0174] Embodiment 25 The window according to embodiment 24, wherein the first glass ply is made from a borosilicate glass composition.

[0175] Embodiment 26 With respect to the constituent oxides, the borosilicate glass composition is SiO2, B2O3, Al2O3, one or more alkali metal oxides, and one or more divalent cation oxides selected from the group consisting of MgO, CaO, SrO, BaO, and ZnO 11 mol% or more and 16 mol% or less of B2O3 2 mol% or more and 6 mol% or less of Al2O3, and a total of 7.0 mol% or more of Na2O, K2O, MgO, and CaO containing The molar percent concentrations of SiO2, B2O3, the one or more alkali metal oxides, Al2O3, and the one or more alkaline earth metal oxides are in the relationship: (R2O + R’O) ≥ Al2O3, and 0.80 < (1 - [(2R2O + 2R’O) / (SiO2 + 2Al2O3 + 2B2O3)]) < 0.93 satisfying wherein R2O is the sum of the concentrations of the one or more alkali metal oxides, and R’O is the sum of the concentrations of the one or more alkaline earth metal oxides, the window according to Embodiment 25.

[0176] Embodiment 27 The window according to any one of Embodiments 20 to 26, wherein the first thickness is at least three times thicker than the second thickness.

[0177] Embodiment 28 The window according to any one of Embodiments 20 to 27, wherein the second glass ply is chemically strengthened so that the second glass ply has a surface compressive stress on the fourth major surface of 250 MPa or more and 900 MPa or less.

[0178] Embodiment 29 The window according to Embodiment 28, wherein when the first glass ply collides with a 1 g ball bearing moving at 160.93 km / h, cracks that penetrate all of the second thickness are not formed.

[0179] Embodiment 30 The window according to any one of Embodiments 20 to 29, wherein the intermediate layer is made of an optically transparent adhesive or an ultraviolet curable acrylic resin.

[0180] Embodiment 31 The window according to Embodiment 30, wherein the intermediate layer has a third thickness of 0.05 mm or more and 1.0 mm or less.

[0181] Embodiment 32 The window according to any one of Embodiments 20 to 31, wherein the wavelength range of interest of 50 nm is centered on a wavelength between 900 nm and 950 nm.

[0182] Embodiment 33 The window according to any one of Embodiments 20 to 31, wherein the wavelength range of interest of 50 nm is centered on a wavelength between 1525 nm and 1575 nm.

[0183] Embodiment 34 The one or more laminated films include a first laminated film disposed on the first major surface, The window according to any one of Embodiments 20 to 33, wherein the window has a maximum hardness of at least 8 GPa as measured by the Vickers indentation hardness test on the first laminated film.

[0184] Embodiment 35 The one or more laminated films include a second laminated film disposed on the fourth major surface, The quantity, thickness, number, and material of the alternating layers of the first and second laminated films are such that the window has, For light incident on the first major surface and the second major surface at an angle of 15° or less, an average reflectance calculated over the wavelength range of interest of 50 nm between 1400 nm and 1600 nm of less than 0.5%, A CIELAB L * value of 45 or less for an incident angle of 60° or less to the first laminated film, and A CIELAB a *and b * value The window according to Embodiment 34, configured to have .

[0185] Embodiment 36 One of the alternating layers of the first laminated film farthest from the first main surface forms the end face material of the window, and the end face material of the window is made of a low refractive index material. The window according to Embodiment 35, wherein the first laminated film is formed from one of the one or more high refractive index materials and includes a scratch-resistant layer having a thickness of 1500 nm or more and 5000 nm or less.

[0186] Embodiment 37 The scratch-resistant layer is separated from the end face by a plurality of layers among the alternating layers of the one or more low refractive index materials and the one or more high refractive index materials of the first laminated film. The window according to Embodiment 36, wherein the scratch-resistant layer is separated from the end face by at least 1000 nm.

[0187] Embodiment 38 The one or more laminated films include a second laminated film disposed on the fourth main surface. The quantity, thickness, and material of the alternating layers of the first and second laminated films are such that the window has For light incident on the first main surface and the second main surface at an incident angle of 15° or less, an average transmittance calculated over the 50 nm wavelength range of interest of more than 90%, For light incident on the first main surface and the second main surface at an angle of 15° or less, an average reflectance calculated over the 50 nm wavelength range of interest of less than 0.5%, and For light incident on the first main surface and the second main surface at an incident angle of 15° or less, an average transmittance calculated from 400 nm to 700 nm of more than 80%. The window according to Embodiment 34, configured to have the above properties.

[0188] Embodiment 39 An emitter that emits radiation in a wavelength range of interest of 50 nm included in a wavelength range from 800 nm to 1800 nm, A sensor configured to detect the radiation emitted by the emitter, An outer enclosure that defines a sensor cavity for housing the emitter and the sensor, and A window according to any one of Embodiments 21 to 38, attached to the outer enclosure so as to seal the sensor cavity, A sensor system comprising the above.

[0189] Embodiment 40 The sensor system according to Embodiment 39, wherein the second glass ply has a dimension larger than that of the first glass ply, and the second glass ply is attached to the outer enclosure such that the first main surface is in the same plane as the front surface of the outer enclosure.

[0190] Embodiment 41 The sensor system according to Embodiment 40, wherein the sensor cavity remains sealed after a 1 g ball bearing moving at 160.93 km / h collides with the window at an incident angle of 45°.

Explanation of Reference Numerals

[0191] 10 Vehicle 12 LIDAR System 14 Roof 16 Front Portion 18 Electromagnetic Radiation Emitter - Sensor 20 Outer Enclosure 22 Emitted Radiation 24 Window 26 External Environment 28 Reflected Radiation 30 Substrate 32 First Surface 34 Second Surface 36 First Layered Film 38 Second Layered Film 40 One or More High Refractive Index Materials 42 One or More Low Refractive Index Materials End face of the first laminated film End face of the second laminated film First glass ply First thickness First major surface of the first glass ply Second major surface of the first glass ply Asymmetric laminate structure Second glass ply Second thickness Third major surface of the second glass ply Fourth major surface of the second glass ply Intermediate layer Third thickness

Claims

1. In a window for a detection system, a first glass ply having a first major surface, a second major surface opposite the first major surface, and a first thickness extending between the first major surface and the second major surface, a second glass ply having a third major surface, a fourth major surface opposite the third major surface, and a second thickness extending between the third major surface and the fourth major surface, an intermediate layer disposed between the first glass ply and the second glass ply, coupling the second major surface to the third major surface, and one or more laminated films disposed on at least one of the first major surface and the fourth major surface, each of the one or more laminated films including alternating layers of one or more high refractive index materials and one or more low refractive index materials, comprising, the intermediate layer, alone, having an average transmittance of greater than 98% over a 50 nm wavelength range of interest for light normally incident on the fourth major surface or the first major surface, the 50 nm wavelength range of interest being included in a wavelength range from 800 nm to 1800 nm, the alternating layers of the one or more laminated films being configured to exhibit an average transmittance of 95% or greater over the 50 nm wavelength range of interest for light normally incident on the first major surface or the fourth major surface of the window, the alternating layers of the one or more laminated films being configured to exhibit an average reflectance of 5% or less over the 50 nm wavelength range of interest for light normally incident on the first major surface or the fourth major surface of the window, the first thickness being at least twice as thick as the second thickness, the second glass ply being strengthened to a greater extent than the first glass ply such that the second glass ply exhibits a central tension greater than the central tension of the central region of the first glass ply, a window.

2. The window according to claim 1, wherein the first glass ply is not strengthened.

3. The first thickness is 2.0 mm or more and 8.0 mm or less, The second thickness is 0.1 mm or more and 1.2 mm or less, the window according to claim 1 or 2.

4. The window according to claim 1 or 2, wherein both the first glass ply and the second glass ply are formed from aluminosilicate glass.

5. The window according to claim 1 or 2, wherein the first glass ply is formed from a glass that exhibits characteristic fracture behavior when a Vickers indenter test is performed.

6. The window according to claim 1 or 2, wherein the first thickness is at least three times thicker than the second thickness. **Claim 7** The window according to claim 1 or 2, wherein the second glass ply is chemically strengthened so that the second glass ply has a surface compressive stress on the fourth major surface of 250 MPa or more and 900 MPa or less. **Claim 8** The window according to claim 7, wherein when the first glass ply collides with a 1 g ball bearing moving at 160.93 km / h, cracks that penetrate all of the second thickness are not formed. **Claim 9** The window according to claim 1 or 2, wherein the intermediate layer is made of an optically transparent adhesive or an ultraviolet curable acrylic resin. **Claim 10** The window according to claim 1 or 2, wherein the wavelength range of interest of 50 nm is centered on a wavelength between 900 nm and 950 nm, or a wavelength between 1525 nm and 1575 nm.

Images