In some aspects, the present description provides an optical stack including a reflective polarizer disposed on, and substantially conforming to, a major surface of an optical lens. The reflective polarizer substantially reflects light having a first polarization state and substantially transmits light having an orthogonal second polarization state. The optical lens can have an optical retardance of greater than 10 nm at a first location in a largest optically active region of the optical lens. A same principal axis of the optical retardance is aligned with a same one of the first and second polarization states to within about 10 degrees at the first location.
In some aspects, the present description provides an optical stack including a reflective polarizer disposed on, and substantially conforming to, a major surface of an optical lens. The reflective polarizer substantially reflects light having a first polarization state and substantially transmits light having an orthogonal second polarization state. The optical lens has an optical retardance of greater than 10 nm at a first location in a largest optically active region of the optical lens. When the optical stack is disposed adjacent an absorbing polarizer with the optical lens disposed between the reflective and absorbing polarizers, where the absorbing polarizer substantially absorbs light having the second polarization state and substantially transmits light having the first polarization state, an optical transmittance through the optical stack and the absorbing polarizer of a substantially collimated light having the second polarization state and incident on the reflective polarizer is less than about 0.5%. The substantially collimated light fills at least a first region of the largest optically active region of the optical lens, where the first region comprises the first location and at least 50% of the largest optically active region of the optical lens.
These and other aspects will be apparent from the following detailed description. In no event, however, should this brief summary be construed to limit the claimable subject matter.
In the following description, reference is made to the accompanying drawings that form a part hereof and in which various embodiments are shown by way of illustration. The drawings are not necessarily to scale. It is to be understood that other embodiments are contemplated and may be made without departing from the scope or spirit of the present description. The following detailed description, therefore, is not to be taken in a limiting sense.
It has typically been desired for optical lenses to have a low retardance since the retardance of the optical lens can have undesired effects on the performance of the optical lens in an optical system. However, according to some embodiments of the present description, it has been found that an optical lens having a relatively high retardance (e.g., an optical retardance of greater than 10 nm) can be useful in a variety of optical systems. For example, according to some embodiments, an optical stack that includes a reflective polarizer disposed on the optical lens with a pass or block axis of the reflective polarizer substantially aligned with a same principal axis (one of a fast axis and a slow axis) of the retardance in at least a region where the retardance is greater than 10 nm, for example, can be used in an optical system without the retardance significantly adversely affecting the performance of the optical system even when the retardance is large. The optical lens can be or include a polymeric lens that is insert molded onto the reflective polarizer. Molded polymeric optical lenses have traditionally been made from resins that result in a low retardance. Since the optical lenses of the present description can have a larger retardance, a wide variety of different (e.g., less expensive) resins may be used in forming the optical lens. In some embodiments, an optical lens comprises at least one of polycarbonate, polystyrene, polyester, amorphous polyolefin, or styrene methyl methacrylate.
The optical retardance can be measured along a same direction (e.g., a direction substantially orthogonal to each of the opposing major surfaces of the optical lens proximate a center of the optical lens) and may be evaluated a wavelength (e.g., 432 nm, 550 nm, or 633 nm) in a visible wavelength range (e.g., about 400 nm to about 700 nm). The same principal axes of the retardance are then along directions orthogonal to the same direction which may be an optical axis (z-axis) of the optical lens 100. The retardance can be specified as a function of location on a major surface of the optical lens. In some embodiments, the optical retardance is greater than 10, 12, 14, 16, 18, or 20 nm in at least a portion of the largest optically active region 120. This optical retardance can be less than 200, 150, or 100 nm, for example. The portion can be in the first region 110 (e.g., at or near location 140) or can be near an outer boundary of the largest optically active region 120. In some embodiments, a maximum thickness (see, e.g., maximum thickness T schematically illustrated in
In some embodiments, an optical stack 200 includes a reflective polarizer 250 disposed on, and substantially conforming to, a major surface 101 of the optical lens 100. The reflective polarizer 250 substantially reflects (e.g., average reflectance greater than 50, 60, 70, 80, or 90 percent for (e.g., substantially normally incident) light in a wavelength range of about 420 nm to about 680 nm) light 113 having a first polarization state 163 and substantially transmits (e.g., average transmittance greater than 50, 60, 70, 80, or 90 percent for (e.g., substantially normally incident) light in a wavelength range of about 420 nm to about 680 nm) light 184 having an orthogonal second polarization state 193. The optical lens 100 can have an optical retardance of greater than 10, 12, 14, 16, 18, or 20 nm at a first location in a largest optically active region 120 of the optical lens 100. The first location can be a location near a center of the lens (e.g., location 140) or a location near the boundary of largest optically active region 120, for example. A same principal axis 107 of the optical retardance can be aligned with a same one of the first and second polarization states 163 and 193 to within about 10, 8, 6, 5, 4, 3 or 2 degrees at the first location. In some embodiments, a same principal axis 107 of the optical retardance can be aligned with the first polarization state 163 to within about 10 degrees for each location in at least 60%, 65%, 70%, 75%, 80%, 85%, or 90% (e.g., by area of the major surface 101) of the largest optically active region 120 of the optical lens 100. In some embodiments, the same principal axis 107 of the optical retardance is aligned with the first polarization state 163 to within about 8, 6, 5, 4, 3, or 2 for each location in at least the specified percentage (e.g., at least 60%) of the largest optically active region 120. The angle between the same principal axis 107 and the polarization state can be understood to be an angle measured in the xy-plane when the retardance is measured along the z-axis. In some embodiments, the same principal axis of the optical retardance is a slow axis and the same one of the first and second polarization states is the first polarization state. In some embodiments, the same principal axis of the optical retardance is a fast axis and the same one of the first and second polarization states is the first polarization state.
The same principal axis 107 of the optical retardance can be aligned with a polarization state by determining the orientation of the same principal axis 107 that results from a direction of resin flow in a mold used to make the optical lens 100 and insert molding the optical lens onto the reflective polarizer with the reflective polarizer disposed in the mold so that the resulting same principal axis 107 of the retardance of the optical lens is aligned with a polarization state (e.g., the first polarizations state 163 so that the same principal axis 107 is substantially along the y-axis or the second polarization state 193 so that the same principal axis 107 is substantially along the x-axis. For example, the polarization state can be along the y-axis and an angle between the polarization state and the same principal axis can be the angle θ illustrated in
In some embodiments, the reflective polarizer 250 is substantially coextensive with the major surface 101 (e.g., coextensive with the major surface 101 except possibly for region(s) near an edge of the major surface 101). In some embodiments, the reflective polarizer 250 is coextensive with greater than 50, 60, 70, 80, or 90 percent of a total area of the major surface 101.
The optical stack 200 may be formed by insert molding the part 105 onto a reflective polarizer substantially coextensive with the portion 102 and then removing the portion 102 with the reflective polarizer from the resulting part. Alternatively, a reflective polarizer may be thermoformed into a desired shape and adhered to the surfaces of the optical lens 100 via an optically clear adhesive for example. Suitable insert molding and thermoforming processes are generally described in U.S. Pat. Appl. Pub. No. 2021/0208320 (Ambur et al.) and in U.S. Pat. No. 11,065,855 (Klun et al.), for example.
In some embodiments, the same principal axis 107 of the optical retardance has an orientation within 01 of a same first direction (e.g., y-direction) for each location in at least P1 of the first region 110 of the optical lens 100. In some embodiments, θ1 is about 5, 4, 3, or 2 degrees. In some such embodiments, or in other embodiments, P1 is at least 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, or 90 percent. For example, in some embodiments, the same principal axis 107 of the optical retardance has an orientation within about 5 degrees of a same first direction for each location in at least 60% of the first region 110 of the optical lens 100, where the first region comprising at least 60% of a largest optically active region 120 of the optical lens 100. In some such embodiments, or in other embodiments, the same principal axis 107 of the optical retardance has an orientation within about 4 degrees of the same first direction for each location in at least 60% of the first region of the polymeric optical lens. In some such embodiments, or in other embodiments, the same principal axis 107 of the optical retardance has an orientation within about 3 degrees of the same first direction for each location in at least 50% of the first region of the polymeric optical lens. In some such embodiments, or in other embodiments, the same principal axis 107 of the optical retardance has an orientation within about 2 degrees of the same first direction for each location in at least 35% of the first region of the polymeric optical lens. As another example, in some embodiments, a same principal axis 107 of the optical retardance has an orientation within about 3 degrees of the same first direction for each location in at least 45% of the first region 110 of the optical lens 100, where the first region comprises at least 60% of the largest optically active region 120 of the optical lens 100. In some such embodiments, or in other embodiments, the same principal axis 107 of the optical retardance has an orientation within about 3 degrees of the same first direction for each location in at least 55% of the first region of the polymeric optical lens. In some such embodiments, or in other embodiments, the same principal axis of the optical retardance has an orientation within about 2 degrees of the same first direction for each location in at least 35% of the first region of the polymeric optical lens. As still another example, in some embodiments, a same principal axis 107 of the optical retardance has an orientation within about 2 degrees of the same first direction for each location in at least 30%, 35%, 40%, 45%, or 50% of the first region 110 of the optical lens 100, where the first region comprises at least 60% of the largest optically active region 120 of the optical lens 100. The first region can include a first location where the optical lens has an optical retardance of greater than 10, 12, 14, 16, 18, or 20 nm, for example.
In some embodiments, the same principal axis 107 of the optical retardance has an orientation within about 10, 8, 6, 5, 4, 3 or 2 degrees of the same one of the first and second polarization states for each location in at least 60% of a first region 110 of the optical lens, where the first region 110 comprises the first location (e.g., location 140) and at least 50% of the largest optically active region 120 of the optical lens 100. In some embodiments, the orientation is within the specified limits for each location in at least 60, 70, 80, 85, or 90 percent of the first region 110 of the optical lens 100. In some such embodiments, or in other embodiments, the first region 110 comprises at least 60, 70, 80, 85 or 90 percent of the largest optically active region 120 of the optical lens 100.
In some embodiments, the same principal axis 107 of the optical retardance has an orientation within about 5, 4, 3 or 2 degrees of the same one of the first and second polarization states for each location in at least 45% of a first region 110 of the optical lens, where the first region 110 comprises the first location (e.g., location 140) and at least 50% of the largest optically active region 120 of the optical lens 100. In some embodiments, the orientation is within the specified limits for each location in at least 50, 60, 70, 80, 85, or 90 percent of the first region 110 of the optical lens 100. In some such embodiments, or in other embodiments, the first region 110 comprises at least 60, 70, 80, 85 or 90 percent of the largest optically active region 120 of the optical lens 100.
In some embodiments, the same principal axis 107 of the optical retardance has an orientation within about 3 or 2 degrees of the same one of the first and second polarization states for each location in at least 30% of a first region 110 of the optical lens, where the first region 110 comprises the first location (e.g., location 140) and at least 50% of the largest optically active region 120 of the optical lens 100. In some embodiments, the orientation is within the specified limits for each location in at least 35, 40, 45, 50, 55, 60, 65, 70, 75, or 80 percent of the first region 110 of the optical lens 100. In some such embodiments, or in other embodiments, the first region 110 comprises at least 60, 70, 80, 85 or 90 percent of the largest optically active region 120 of the optical lens 100.
The orientation of the same principal axis of the retardance of the optical lens can be described in terms of 01, P1, as described elsewhere herein. Alternatively, or additionally, the orientation of the same principal axis of the retardance may be described in terms of an average of a magnitude of an orientation angle of a same principal axis of a retardance in a region of the optical lens.
In some embodiments, a same principal axis 107 of the optical retardance has a first orientation 107a at a first location 140 of the optical lens 100, where an average (Aθ) in a first region 110 of the optical lens 100 of a magnitude of an angle of the same principal axis relative to the first orientation is less than κ, 4.5, 4, 3.5, 3.25 or 3 degrees, where in a plan view, the first region 110 is a circular region substantially centered on the first location 140 and having a diameter D1 of at least 50% of a diameter DO of the largest optically active region 120 of the optical lens 100. In some embodiments, D1 is at least 55, 60, 65, 70, 75, or 80 percent of DO. In some embodiments, the plan view is along a direction substantially orthogonal to each of the opposing major surfaces of the optical lens proximate a center of the optical lens (e.g., an optical axis of the optical lens 100.
The substantially collimated light 185 can be incident on the optical stack 200 along a first direction substantially orthogonal to each of the opposing major surfaces of the optical lens proximate a center of the optical lens (e.g., along an optical axis of the optical lens 100). The absorbing polarizer 280 can be disposed so that the first direction is orthogonal to the absorbing polarizer 280 and so that the light transmitted through the optical stack is incident on the absorbing polarizer 280.
If the optical lens 100 had a zero retardance or a retardance with a fast or slow axis aligned with the second polarization state 193, the absorbing polarizer 280 would absorb light transmitted through the lens 100 so that substantially no light is transmitted through the absorbing polarizer 280. In contrast, a polymeric lens having a birefringence of 20 nm with a same principal axis oriented at a 45 degrees to the first and second polarization states 163 and 193, for example, would result in a transmittance through the absorbing polarizer 280 of about 1.3% of the incident light.
Terms such as “about” will be understood in the context in which they are used and described in the present description by one of ordinary skill in the art. If the use of “about” as applied to quantities expressing feature sizes, amounts, and physical properties is not otherwise clear to one of ordinary skill in the art in the context in which it is used and described in the present description, “about” will be understood to mean within 10 percent of the specified value. A quantity given as about a specified value can be precisely the specified value. For example, if it is not otherwise clear to one of ordinary skill in the art in the context in which it is used and described in the present description, a quantity having a value of about 1, means that the quantity has a value between 0.9 and 1.1, and that the value could be 1.
Terms such as “substantially” will be understood in the context in which they are used and described in the present description by one of ordinary skill in the art. If the use of “substantially” with reference to a property or characteristic is not otherwise clear to one of ordinary skill in the art in the context in which it is used and described in the present description and when it would be clear to one of ordinary skill in the art what is meant by an opposite of that property or characteristic, the term “substantially” will be understood to mean that the property or characteristic is exhibited to a greater extent than the opposite of that property or characteristic is exhibited.
All references, patents, and patent applications referenced in the foregoing are hereby incorporated herein by reference in their entirety in a consistent manner. In the event of inconsistencies or contradictions between portions of the incorporated references and this application, the information in the preceding description shall control.
Descriptions for elements in figures should be understood to apply equally to corresponding elements in other figures, unless indicated otherwise. Although specific embodiments have been illustrated and described herein, it will be appreciated by those of ordinary skill in the art that a variety of alternate and/or equivalent implementations can be substituted for the specific embodiments shown and described without departing from the scope of the present disclosure. This application is intended to cover any adaptations, or variations, or combinations of the specific embodiments discussed herein. Therefore, it is intended that this disclosure be limited only by the claims and the equivalents thereof.
Filing Document | Filing Date | Country | Kind |
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PCT/IB2022/061554 | 11/29/2022 | WO |
Number | Date | Country | |
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63290131 | Dec 2021 | US |