Optical laminates and displays

Abstract

The optical stack includes a reflective polarizer including a plurality of interference layers and an absorptive polarizer disposed on the reflective polarizer. The plurality of interference layers transmit at least about 85% of incident light having a first polarization state, reflect at least about 80% of incident light having a second polarization state, and transmit less than about 0.1% of incident light having the second polarization state. The absorptive polarizer has a first transmittance for the first polarization state and a second transmittance for the second polarization state. The average of the first transmittance and the second transmittance is greater than about 0.46. The second transmittance has a first standard deviation. The optical stack has a transmittance for the second polarization state with a second standard deviation that is at least about 10% smaller than the first standard deviation. The display includes the optical stack.

Description

Background Art

[0001] The display may include a reflective polarizer and an absorptive polarizer.

Summary of the Invention

[0002] The present disclosure relates to an optical laminate and a display. The optical laminate may include a reflective polarizer and an absorptive polarizer disposed on the reflective polarizer. The display may include the optical laminate. The reflective polarizer can be a high-contrast reflective polarizer (e.g., having a transmittance of at least about 0.85 with respect to the transmitted polarization state for at least one visible wavelength, having a transmittance of less than about 0.001 with respect to the blocked polarization state for at least one visible wavelength, and / or having a polarization efficiency of greater than about 0.995 for at least one visible wavelength). The absorptive polarizer can have a high average transmittance (e.g., a transmittance with respect to non-polarized light of greater than about 0.46 for at least one visible wavelength) and / or a high standard deviation of the blocked-state transmittance and / or polarization efficiency (compared to conventional absorptive polarizers) (e.g., the standard deviation of the blocked-state transmittance can be greater than about 0.0035, and / or the standard deviation of the polarization efficiency can be greater than about 0.005). According to some embodiments, it has been found that optical defects due to the high standard deviation of the blocked-state transmittance and / or polarization efficiency can be substantially reduced or eliminated by the presence of the reflective polarizer.

[0003] In some embodiments, the Disclosure provides an optical laminate comprising a reflective polarizer and an absorptive polarizer disposed on the reflective polarizer and having substantially the same extent as the reflective polarizer. The reflective polarizer comprises a plurality of interference layers. The optical laminate is such that, with respect to substantially perpendicular incident light and at least a first wavelength between about 450 nm and about 670 nm, each interference layer reflects or transmits light primarily by optical interference, the plurality of interference layers transmit at least about 85% of incident light having a first polarization state, reflect at least about 80% of incident light having an orthogonal second polarization state, and transmit less than about 0.1% of incident light having a second polarization state, and the absorptive polarizer has a first light transmittance for the first polarization state, an absorptive rate of more than about 50% for the second polarization state, and a second light transmittance for the second polarization state. The average of the first light transmittance and the second light transmittance can be greater than about 0.46. The second light transmittance has the first standard deviation over at least 80% of the absorbing polarizer. The optical laminate has a light transmittance for a second polarization state, having the second standard deviation over at least 80% of the optical laminate. The second standard deviation can be at least about 10% smaller than the first standard deviation.

[0004] In some embodiments, the Disclosure provides a display comprising: a display panel having an active region configured to display an image; an extended light source configured to supply illumination to the display panel; a reflective polarizer disposed between the display panel and the extended light source; and an absorptive polarizer disposed between the display panel and the reflective polarizer. The reflective polarizer comprises a plurality of polymer layers totaling at least 50, each polymer layer having an average thickness of less than about 500 nm. The extended light source, the active region of the display panel, the reflective polarizer, and the absorptive polarizer may have substantially the same extent as each other. The display may be such that, with respect to substantially perpendicular incident light and with respect to at least one wavelength between about 450 nm and about 650 nm, the polarization efficiency of the reflective polarizer across the active region of the display panel has an average of greater than about 0.995 and a standard deviation of less than about 0.001, and the polarization efficiency of the absorptive polarizer across the active region of the display panel has an average of less than about 0.93 and a standard deviation of greater than about 0.005.

[0005] These and other embodiments will become apparent from the following “Modes for Carrying Out the Invention.” However, in no event should this brief summary be construed as limiting the subject matter for which claims are applicable. [Brief explanation of the drawing]

[0006] [Figure 1] This is a schematic cross-sectional view of an optical laminate. [Figure 2] This is a schematic cross-sectional view of a reflective polarizer. [Figure 3] This is a schematic cross-sectional view of the display. [Figure 4] This is a schematic diagram of wavelengths within the wavelength range. [Figure 5] This is a schematic diagram of light incident substantially perpendicularly on an element or layer. [Figure 6A] This is a plot of light transmission versus wavelength for a reflective polarizer. [Figure 6B]This is an enlarged view of the plot in Figure 6A. [Figure 6C] This is an enlarged view of the plot in Figure 6A. [Figure 6D] This is a plot of the average polarization efficiency versus wavelength for a reflective polarizer. [Figure 6E] This is a plot of the standard deviation of polarization efficiency versus wavelength for a reflective polarizer. [Figure 6F] This is an enlarged view of the plot in Figure 6E. [Figure 7] This is a schematic diagram of the light transmittance of an absorbing polarizer and an optical laminate. [Figure 8] This is a schematic diagram of the polarization efficiency of absorbing and reflective polarizers. [Figure 9] This is a schematic plot of light absorption versus wavelength for an absorbing polarizer. [Figure 10A] These are plots of light transmission versus wavelength for an absorbing polarizer for the first and second polarization states, respectively. [Figure 10B] These are plots of light transmission versus wavelength for an absorbing polarizer for the first and second polarization states, respectively. [Figure 10C] This is a plot of the average light transmittance for the first polarization state and the second light transmittance for the second polarization state for an absorbing polarizer. [Figure 10D] This is a plot of the standard deviation of light transmittance for absorbing polarizers. [Figure 10E] This is a plot of average polarization efficiency versus wavelength for an absorbing polarizer. [Figure 10F] This is a plot of the standard deviation of polarization efficiency versus wavelength for an absorbing polarizer. [Figure 11A] These are plots of light transmission versus wavelength for the optical laminate, for the first and second polarization states, respectively. [Figure 11B] These are plots of light transmission versus wavelength for the optical laminate, for the first and second polarization states, respectively. [Figure 11C]This is a plot of the standard deviation versus wavelength of the light transmittance for a second polarization state in an optical laminate. [Modes for carrying out the invention]

[0007] The following description refers to the accompanying drawings, which constitute part of this specification and illustrate various embodiments. The drawings are not necessarily to exact scale. It should be understood that other embodiments can be conceived and carried out without departing from the scope or spirit of this specification. Therefore, the following “Modes for Carrying Out the Invention” should not be construed as restrictive.

[0008] The optical laminate may include a reflective polarizer and an absorptive polarizer positioned on the reflective polarizer. In some embodiments, this absorptive polarizer is less powerful (e.g., has a higher average transmittance and / or lower polarization efficiency) than conventional absorptive polarizers. Less powerful absorptive polarizers can be fabricated, for example, by reducing the thickness and / or iodine concentration compared to conventional iodine-dyed polyvinyl alcohol absorptive polarizers. Less powerful absorptive polarizers are typically found to have greater spatial variability in block state transmittance and / or greater spatial variability in polarization efficiency than conventional absorptive polarizers. Such variability leads to optical defects in many applications. However, according to some embodiments, when an optical laminate or display includes a weak absorpturing polarizer combined with a high-contrast reflective polarizer (e.g., transmittance of less than about 0.1% in a block state and / or polarization efficiency greater than about 0.995), it has been found that variations in the absorpturing polarizer do not cause visible or significant optical defects. Furthermore, in some embodiments, weak absorptionIt has been found that using polarizers can result in higher overall transmittance, which can lead to improved efficiency in display systems, for example. For example, in liquid crystal display (LCD) systems, according to some embodiments, a combination of absorbing and reflective polarizers has been found to produce higher brightness compared to conventional displays, without a significant decrease in contrast ratio, or even with an increase in contrast ratio.

[0009] Figure 1 is a schematic cross-sectional view of an optical laminate 1000, which includes a reflective polarizer 100 and an absorbing polarizer 200 positioned on the reflective polarizer 100 and having substantially the same extent as the reflective polarizer 100. The optical laminate 1000 may optionally include additional layers. For example, in some embodiments, the optical laminate includes one or more of the following, positioned on the reflective polarizer 100 on the side opposite to the absorbing polarizer 200: a hard coat layer, a retarder layer (e.g., a quarter-wavelength retarder), or a diffuser layer.

[0010] The reflective polarizer 100 can be a multilayer optical film reflective polarizer. As is known in the art, by using a multilayer optical film including alternately arranged polymer layers and suitably selecting the layer thicknesses, desired reflection and transmission bands can be achieved. Multilayer optical films and methods for manufacturing multilayer optical films are described, for example, in U.S. Patent Nos. 5,882,774 (Jonza et al.), 6,179,948 (Merrill et al.), 6,783,349 (Neavin et al.), 6,967,778 (Wheatley et al.), and 9,162,406 (Neavin et al.). High contrast reflective polarizers (e.g., having a low block state transmittance and / or a high polarization efficiency) can be fabricated, for example, by using two packets of alternately arranged polymer layers that provide reflection in a substantially overlapping wavelength range. High contrast reflective polarizers are described in International Application Publication No. 2018 / 163009 (Haag et al.) and corresponding U.S. Patent Application No. 16 / 487109 (Haag et al.).

[0011] An additional advantage of the reflective polarizer 100 is that, according to some embodiments, this polarizer can provide improved environmental performance. For example, in some embodiments, the reflective polarizer 100 includes more polymer layers than conventional reflective polarizers and thus has a lower moisture vapor transmission rate (MVTR) than conventional reflective polarizers. The MVTR can be determined using a MOCON MVTR test system (available from MOCON, Inc. (Brooklyn Park, MN)) at 23°C. In some embodiments, the reflective polarizer 100 has an MVTR of less than about 4 g / m 2 -day or less than about 3 g / m 2 -day (e.g., about 2 g / m 2 -day). For comparison, an APF-V3 reflective polarizer (available from 3M Company (St. Paul, MN)) has an MVTR of about 7 g / m 2An 80-micrometer-thick cellulose triacetate (TAC) film, which has the same MVTR measured under the same conditions as the -day and is a typical film used for barrier protection of iodine-stained polyvinyl alcohol-absorbing polarizers, has an MVTR of about 40 g / m 2 -day MVTR.

[0012] In some embodiments, the absorbing polarizer 200 is joined to the reflective polarizer 100. For example, an adhesive layer can be used to join the absorbing polarizer 200 to the reflective polarizer 100. As another example, the absorbing polarizer 200 can be formed on the reflective polarizer 100, and as a result, the absorbing polarizer 200 can be joined to the reflective polarizer 100. In some embodiments, the absorbing polarizer is coated on the reflective polarizer. For example, a polyvinyl alcohol solution can be coated on the multilayer optical film before the film is oriented, and then, after the coated film is substantially uniaxially oriented, the oriented polyvinyl alcohol can be stained with an iodine and / or dye-based solution. A polarizer including a reflective polarizer and an absorbing polarizer coated on the reflective polarizer is described in U.S. Patent No. 6,096,375 (Ouderkirk et al.). In some embodiments, the absorbing polarizer is less powerful (e.g., higher average transmittance and / or lower polarization efficiency) than a conventional absorbing polarizer. A relatively less powerful absorbing polarizer can be made, for example, by using a thinner polyvinyl alcohol layer and / or a lower concentration of iodine solution or other staining solution. In some embodiments, the absorbing polarizer is an iodine-stained polyvinyl alcohol (PVOH) polarizer.

[0013] Figure 2 is a schematic cross-sectional view of a reflective polarizer 100 according to several embodiments. The reflective polarizer 100 includes a plurality of interference layers 110, 111. The interference layers 110, 111 can be a plurality of polymer layers totaling at least 50. Each layer 110, 111 may have an average thickness (average thickness across layers) of, for example, less than about 500 nm or less than about 400 nm. The interference layers 110, 111 can reflect or transmit light mainly by optical interference. An interference layer may be described as reflecting or transmitting light mainly by optical interference if its reflectance and transmittance can be reasonably explained by optical interference, or can be reasonably accurately modeled as being due to optical interference. The reflective polarizer 100 may optionally include additional layers 130, 133 which can be optically thick (e.g., average thickness greater than about 1 micrometer or greater than about 2 micrometers). The additional layers 130, 133 may include the outermost skin layer 130 and / or a protective boundary layer 133 between adjacent packets of the interference layers 110, 111. The multiple interference layers may include alternating first polymer interference layers (110) and second polymer interference layers (111).

[0014] The optical laminate 1000 can be used in a display. For example, in some embodiments, the display includes a display panel, an extended light source (e.g., a light guide having a suitable light extraction section and a suitable light source for supplying light to the light guide) configured to supply illumination to the display panel, and an optical laminate 1000 positioned between the display panel and the extended light source, having an absorbing polarizer 200 facing the display panel and a reflective polarizer facing the extended light source.

[0015] Figure 3 is a schematic cross-sectional view of a display 2000, which includes a display panel 300 including an active area 310 configured to display an image 312, an extended light source 400 configured to supply illumination 410 to the display panel 300, a reflective polarizer 100 positioned between the display panel 300 and the extended light source 400, and an absorptive polarizer 200 positioned between the display panel 300 and the reflective polarizer 100. As further described elsewhere, the reflective polarizer 100 may include a plurality of polymer layers totaling at least 50, each polymer layer having an average thickness of less than about 500 nm. The absorptive polarizer 200 can be positioned on the reflective polarizer 100, as further described elsewhere in this specification, to form an optical laminate 1000. The display 2000 may optionally include additional layers. For example, a prism film and / or diffuser may be positioned between the reflective polarizer 100 and the extended light source 400. Alternatively, in some embodiments, the prism film and / or diffuser may be part of the extended light source 400. For example, the extended light source 400 may include a light guide and a prism and / or diffuser positioned on the light guide.

[0016] In some embodiments, the extended light source 400, the active area 310 of the display panel 300, the reflective polarizer 100, and the absorbing polarizer 200 have substantially the same extent as each other. Layers or elements can be described as having substantially the same extent if at least about 60% of each layer or element has the same extent as at least about 60% of each other layer or element. In some embodiments, with respect to layers or elements described as having substantially the same extent as each other, at least about 80% or at least about 90% of each layer or element has the same extent as at least about 80% or at least about 90% of each other layer or element.

[0017] The transmission, reflection, and / or absorption characteristics of the reflective polarizer 100, the absorptive polarizer 200, and / or the optical laminate 1000 can be described with respect to substantially normally incident light, or with respect to light at one or more angles of incidence, and with respect to one or more wavelengths within a certain wavelength range, or the values ​​can be averaged over a certain wavelength range. In the case of the optical laminate 1000, transmission and reflection can be measured with respect to light incident on the reflective polarizer 100.

[0018] Figure 4 is a schematic diagram of wavelengths λ within the wavelength range λ1 to λ2. λ1 can be, for example, approximately 400 nm, 430 nm, or 450 nm. λ2 can be, for example, approximately 650 nm, 670 nm, or 700 nm. Wavelength λ can be, for example, approximately 500 nm, 550 nm, 600 nm, or 650 nm.

[0019] Figure 5 is a schematic diagram of light 120 substantially perpendicularly incident on an element or layer 500 (e.g., within 30 degrees, 20 degrees, 10 degrees, or 5 degrees from perpendicular incidence). The element or layer 500 can be, for example, a reflective polarizer, an absorptive polarizer, or an optical laminate. Light 120 may have a first polarization state (e.g., polarized along the x-axis, referring to the xyz coordinate system in Figures 1 and 2), or a second orthogonal polarization state (e.g., polarized along the y-axis), or light 120 may be unpolarized. The first polarization state can be a passing polarization state, and the second polarization state can be a blocking polarization state.

[0020] The block axes of the reflective polarizer 100 and the absorptive polarizer 200 can be substantially aligned (for example, within 10 degrees, 5 degrees, or 3 degrees from parallel). For example, the block axes of the reflective polarizer 100 and the absorptive polarizer 200 can each be substantially parallel to the y-axis.

[0021] Figure 6A is a plot of light transmission (light transmittance × 100%) versus wavelength for a reflective polarizer 100 in several embodiments, with respect to substantially normally incident light in a first polarization state (pass-through state) and a second polarization state (blocking state). Transmission is shown with respect to four spaced points (indicated as P1 to P4). In some embodiments, light absorption by the reflective polarizer can be ignored, so the light reflection R (light reflectance × 100%) is approximately 100% minus the light transmission. Figure 6B is an enlarged portion of the plot in Figure 6A, showing light transmission for substantially normally incident light in the second polarization state (blocking state). Figure 6C is an enlarged portion of the plot in Figure 6A, showing light transmission for substantially normally incident light in the first polarization state (pass-through state).

[0022] Figure 6D is a plot of average polarization efficiency versus wavelength for a reflective polarizer 100 in several embodiments. Polarization efficiency can be expressed as the square root of (Tp-Tb) / (Tp+Tb) in terms of the transmittance Tp of the pass-state light with respect to substantially perpendicular incident light 120 and the transmittance Tb of the block-state light with respect to substantially perpendicular incident light 120. Figure 6E is a plot of the standard deviation versus wavelength of polarization efficiency for a reflective polarizer 100 in several embodiments. Figure 6F is an enlarged portion of the plot in Figure 6E.

[0023] The standard deviation of polarization efficiency or block state transmittance refers to the standard deviation of the distribution over a certain region (e.g., at least 80% of the polarizer's area, or the polarizer's area having the same extent as the active area of ​​the display panel). The mean and standard deviation can be determined using measurements at spaced points (e.g., 4 to 30 points), for example, four, or at least four, or at least ten, or at least twenty points. These points can be spaced, for example, 0.5 to 10 cm apart, and for larger samples, larger spacing can be used. The mean and standard deviation can be determined with respect to the mean at a certain wavelength (e.g., about 500 nm or about 550 nm) or over a certain wavelength range (e.g., about 450 nm to about 650 nm).

[0024] The plots shown in Figures 6A to 6F were determined from transmission measurements performed at four spaced positions on a reflective polarizer, as outlined in Example 1 of International Patent Publication No. 2018 / 163009 (Haag et al.). Transmission measurements for the optical laminate, reflective polarizer, and absorptive polarizer were performed on a LAMBDA1050 UV / Vis / NIR spectrophotometer (available from PerkinElmer, Inc. (Waltham, MA)). In the measurement of the optical laminate, the reflective polarizer faced the light source and the absorptive polarizer faced the detector. Reflective polarizer 100 may correspond to this reflective polarizer, or to other reflective polarizers described in International Patent Publication No. 2018 / 163009 (Haag et al.), or to yet other reflective polarizers having the optical properties described elsewhere in this specification.

[0025] In some embodiments, the optical laminate 1000 is such that, with respect to substantially perpendicular incident light 120 and at least a first wavelength (e.g., λ), each interference layer 110, 111 reflects or transmits light mainly by optical interference, and the plurality of interference layers 110, 111 transmit at least about 85% of incident light having a first polarization state (e.g., x-axis) (see, e.g., Figure 6A), reflect at least about 80% of incident light having an orthogonal second polarization state (e.g., y-axis) (see, e.g., Figure 6A), transmit less than about 0.1% of incident light having a second polarization state (see, e.g., Figure 6B), and the absorbing polarizer 200 has a first light transmittance for the first polarization state (see, e.g., Figure 10A), an absorptive light absorption of more than 50% for the second polarization state (see, e.g., Figure 9), and a second light transmittance for the second polarization state (see, e.g., Figure 10B). In some embodiments, the multiple interference layers 110, 111 transmit less than about 0.05% of the incident light having a second polarization state (see, for example, Figure 6B). At least the first wavelength can be between wavelengths λ1 and λ2, as described elsewhere in this specification. For example, at least the first wavelength can be between about 450 nm and about 670 nm, or between about 450 nm and about 650 nm. In some embodiments, the first wavelength is, for example, about 550 nm.

[0026] The average of the first and second light transmittances (see, for example, Figure 10C) can be greater than approximately 0.46, or greater than approximately 0.465, or greater than approximately 0.47, or greater than approximately 0.475, or greater than approximately 0.48. In the context of the average of the first and second light transmittances, for example, approximately 0.46 can be, for example, 0.455, or 0.46, or 0.465, or any value between 0.455 and 0.465. As another example, the average of approximately 0.465 can be, for example, 0.46, or 0.465, or 0.47, or any value between 0.46 and 0.47. As yet another example, the average of approximately 0.47 can be, for example, 0.464, or 0.47, or 0.476, or any value between 0.464 and 0.476. In some embodiments, the average of the first light transmittance and the second light transmittance is greater than 0.455.

[0027] Figure 7 is a schematic diagram showing the spatial variation of the light transmittance 220 of an absorbing polarizer 200 and the spatial variation of the light transmittance 320 of an optical laminate 1000 in several embodiments. The light transmittances 220 and 320 can be for a first polarization state (pass-through state), a second polarization state (blocking state), or unpolarized. The light transmittance 220 has a mean (average value over position) of μ1 and a standard deviation of σ1. The light transmittance 320 has a mean (average value) of μ2 and a standard deviation of σ2. The mean and standard deviation can be determined with respect to various positions (e.g., over at least 80% of the polarizer or optical laminate) and with respect to a certain wavelength (e.g., λ) or with respect to the average over a certain wavelength range (e.g., λ1 to λ2). In some embodiments, μ1 > μ2 and σ1 > σ2.

[0028] In some embodiments, the second light transmittance (e.g., 220) has a first standard deviation (e.g., σ1) over at least 80% of the absorbing polarizer 200, and the optical laminate has a light transmittance (e.g., 320) for a second polarization state, having a second standard deviation (e.g., σ2) over at least 80% of the optical laminate, where the second standard deviation is at least about 10% smaller than the first standard deviation. In some embodiments, the first standard deviation (e.g., σ1) is, for example, greater than about 0.0033, or greater than about 0.0035, or about 0.004 It is greater than, or about 0.0045 greater than, or about 0.005 greater than, or about 0.005 greater than, or in some such embodiments, or in other embodiments, the second standard deviation (e.g., σ²) is, for example, less than about 0.0001, or less than about 0.00002, or less than about 0.00001. In some embodiments, the first standard deviation divided by the second standard deviation is at least about 2, or at least about 10, or at least about 100, or at least about 200, or at least about 300, or at least about 400.

[0029] In some embodiments, with respect to substantially normally incident unpolarized light (e.g., 120) and a first wavelength range of about 450 nm to about 650 nm, the absorbing polarizer 200 has an averaged light transmittance over the first wavelength range with a third standard deviation (e.g., σ1) over at least 80% of the absorbing polarizer 200, and the optical laminate has an averaged light transmittance over the first wavelength range with a fourth standard deviation (e.g., σ2) over at least 80% of the optical laminate. The fourth standard deviation can be at least about 10% smaller than the third standard deviation. In some embodiments, the third standard deviation is greater than about 0.005, or greater than about 0.006, or greater than about 0.65. In some such embodiments, or in other embodiments, the fourth standard deviation is less than about 0.0055, or less than about 0.005, or less than about 0.0045.

[0030] Figure 8 is a schematic diagram showing the spatial variation of the polarization efficiency 260 of an absorbing polarizer 200 and the spatial variation of the polarization efficiency 160 of a reflective polarizer 100 in some embodiments. The polarization efficiency 260 has a mean (mean value over position) of μ3 and a standard deviation of σ3. The polarization efficiency 160 has a mean (mean value) of μ4 and a standard deviation of σ4. The mean and standard deviation can be determined with respect to various positions (e.g., over at least 80% of the polarizer) and with respect to a certain wavelength (e.g., λ) or with respect to the mean over a wavelength range (e.g., λ1 to λ2). In some embodiments, μ4 > μ3 and σ4 < σ3.

[0031] In some embodiments, the display 2000 has a polarization efficiency of a reflective polarizer 100 over the active region 310 of the display panel 300 with respect to substantially normally incident light 120 and at least one wavelength (e.g., λ), with respect to an average (e.g., μ4) greater than about 0.995 and a standard deviation (e.g., σ4) less than about 0.001, and a polarization efficiency of an absorptive polarizer 200 over the active region 310 of the display panel 300, with respect to an average (e.g., μ3) less than about 0.93 and a standard deviation (e.g., σ3) greater than about 0.005. In the context of polarization efficiency, a value of about 0.93, for example, can be, for example, 0.92, or 0.93, or 0.94, or any value between 0.92 and 0.94. As another example, a polarization efficiency of approximately 0.999 can be any value between 0.9988 and 0.9992, for example, 0.9988, 0.999, or 0.9992. As yet another example, a polarization efficiency of approximately 0.995 can be any value between 0.994 and 0.996, for example, 0.994, 0.995, or 0.996. In some embodiments, the standard deviation of the polarization efficiency of the reflective polarizer 100 is less than approximately 0.0005, or less than approximately 0.0001, or less than approximately 0.00005. In some embodiments, the standard deviation of the polarization efficiency of the absorptive polarizer 200 is greater than approximately 0.0055, or greater than approximately 0.006, or greater than approximately 0.0065, or greater than approximately 0.007. In some embodiments, the average polarization efficiency of the absorbing polarizer 200 is less than about 0.92 or less than about 0.91. In some embodiments, the average polarization efficiency of the reflective polarizer 100 is greater than about 0.999, greater than about 0.9995, greater than about 0.9998, or greater than about 0.9999.

[0032] At least one wavelength can be between λ1 and λ2, as described elsewhere in this specification. For example, at least one wavelength can be between approximately 450 nm and approximately 650 nm.

[0033] In some embodiments, with respect to substantially perpendicular incident light 120 and in the wavelength range of about 450 nm to about 650 nm, the absorbing polarizer 200 has a polarization efficiency over the active region 310 of the display panel 300, averaged over the wavelength range, with a mean (e.g., μ3) of less than about 0.945 and a standard deviation (e.g., σ3) greater than about 0.0045 (the polarization efficiency is averaged over wavelengths within the wavelength range and varies with position on the absorbing polarizer).

[0034] Figure 9 is a schematic plot of light absorption versus wavelength for an absorbing polarizer 200 in several embodiments. In some embodiments, with respect to substantially normally incident light 120 and at least a first wavelength (e.g., λ) between about 450 nm and about 670 nm, or between about 450 nm and about 650 nm, the absorbing polarizer 200 has a light absorption of more than about 50% for a second polarization state. In some embodiments, the light absorption of the absorbing polarizer is more than about 60%, or more than about 70%, or more than about 80% for a second polarization state.

[0035] Figures 10A and 10B are plots of light transmission versus wavelength for an absorbing polarizer with respect to substantially normally incident light 120 in the first polarization state (pass-through state) and the second polarization state (blocking state), respectively. These plots are for the first absorbing polarizer (sample "S1") and the second absorbing polarizer (sample "S2"). For each polarizer, curves measured at four spaced positions are shown. The first absorbing polarizer "S1" was prepared by oriented a polyvinyl alcohol (PVOH) layer (for the polyvinyl alcohol, KURARAY POVAL 28-99, available from KURARAY Co., Ltd. (Tokyo, JP) was used) and staining it with iodine. The thickness of the PVOH layer and the concentration of iodine were selected to produce the transmission shown in Figures 10A and 10B. A second absorbing polarizer, "S2," was similarly fabricated, but it used a PVOH layer with approximately 50% of the thickness of the first absorbing polarizer, "S1." The first absorbing polarizer is a conventional polarizer. absorptionThe first type of polarizer is significantly less powerful than the second type of polarizer, and the second type of absorptive polarizer is even less powerful. For example, with respect to substantially perpendicular incident light in the wavelength range of approximately 450 nm to approximately 650 nm, the conventional SANRITZ absorptive polarizer has an average block state transmittance of approximately 0.007%, the first type of absorptive polarizer has an average block state transmittance of approximately 1.4%, and the second type of absorptive polarizer has an average block state transmittance of approximately 5.2%.

[0036] In some embodiments, with respect to substantially normally incident light 120 and at least a first wavelength (e.g., λ) between about 450 nm and about 670 nm, or between about 450 nm and about 650 nm, the absorbing polarizer 200 has a light transmittance of more than about 4% for the second polarization state. In some embodiments, the average light transmittance of the absorbing polarizer (e.g., averaged over a region of at least 80% of the absorbing polarizer) is more than about 5%, or more than about 6%, or more than about 7% for the second polarization state. For example, in the embodiment of Figure 10B ("S2"), the average light transmittance is about 8.5% for the second polarization state at a wavelength of about 500 nm.

[0037] Figure 10C is a plot of the average light transmittance for the first polarization state and the second light transmittance for the second polarization state for an absorbing polarizer. The curve in Figure 10C was obtained by averaging the transmittances determined at four points from the curves in Figures 10A and 10B. For the second absorbing polarizer "S2", the average is, for example, 0.4554 at 500 nm and 0.4707 at 670 nm.

[0038] Figure 10D is a plot of the standard deviation of the light transmittance of an absorbing polarizer with respect to substantially normally incident light 120 having a second (block) polarization state, versus wavelength. The curve in Figure 10D was obtained by determining the standard deviation of the transmittance at four points from the curve in Figure 10B. In some embodiments, the absorbing polarizer 200 has a light transmittance with respect to substantially normally incident light 120 with respect to the second polarization state, with a standard deviation greater than about 0.001 or greater than about 0.0015 over the entire wavelength range, at least from about 450 nm to about 650 nm.

[0039] Figure 10E is a plot of the average polarization efficiency versus wavelength for an absorbing polarizer with respect to substantially normally incident light 120. Figure 10F is a plot of the standard deviation of the polarization efficiency versus wavelength for an absorbing polarizer with respect to substantially normally incident light 120. In some embodiments, the absorbing polarizer 200 has a polarization efficiency with respect to substantially normally incident light 120 with respect to a second polarization state, having a standard deviation greater than about 0.0015 or greater than about 0.002 over the entire wavelength range from at least about 450 nm to about 650 nm. The curves in Figures 10E and 10F were determined by determining the mean and standard deviation of the polarization efficiency determined at four points from the curves in Figures 10A and 10B. For the second absorbing polarizer "S2", the average polarization efficiency is 0.902 at a wavelength of 500 nm, and the standard deviation of the polarization efficiency is 0.00852.

[0040] In some embodiments, the absorptive polarizer 200 has the light transmittance and other optical properties described elsewhere in this specification with respect to the second absorptive polarizer "S2". In some embodiments, the absorptive polarizer 200 is another absorptive polarizer having the optical properties described elsewhere in this specification. In some embodiments, the absorptive polarizer 200 has the light transmittance and other optical properties of a third absorptive polarizer that is thinner than the second absorptive polarizer. The thinner absorptive polarizer is expected to have a higher average transmittance than, for example, the one shown in Figure 10C, a higher standard deviation block state transmittance than, for example, the one shown in Figure 10D, a lower polarization efficiency than, for example, the one shown in Figure 10E, and a higher standard deviation polarization efficiency than, for example, the one shown in Figure 10F.

[0041] Figures 11A and 11B are plots of light transmission versus wavelength for an optical laminate with respect to substantially normally incident light 120 in a first polarization state (pass-through state) and a second polarization state (blocking state), respectively. These plots relate to an optical laminate containing a reflective polarizer and a first absorbing polarizer ("S1"), and an optical laminate containing a reflective polarizer and a second absorbing polarizer ("S2") having approximately 50% the thickness of the first absorbing polarizer. The reflective polarizer used in these plots is the same reflective polarizer used in the plots in Figures 6A to 6F. For each polarizer, curves measured at four spaced positions are shown. Figure 11C is a plot of the standard deviation versus wavelength of light transmittance for an optical laminate with respect to substantially normally incident light in a second polarization state (blocking state).

[0042] For the reflective polarizers ("RP") in Figures 6A to 6F, the first absorbing polarizer ("S1") and the second absorbing polarizer ("S2") in Figures 10A to 10F, and the optical laminates in Figures 11A and 11B, the transmission, average transmittance (average of block transmission and through transmission divided by 100%), and polarization efficiency in both the block and through states were determined at four points on the sample. For each of these four points, the values ​​were averaged over the wavelength range of 450 nm to 650 nm. The mean and standard deviation of the wavelength-averaged values ​​determined at these points were determined and reported in the following table, with the standard deviation in parentheses next to the mean. For comparison, commercially available SANRITZ polarizers were similarly tested, and the results are included in the following table. [Table 1]

[0043] Terms such as “about” will be understood by those skilled in the art in the context in which they are used and described herein. Where it is not particularly clear to those skilled in the art in the context in which they are used and described herein, “about” will be understood to mean within 5 percent of a specified value. A quantity given as “about” a specified value may be exactly that specified value. For example, where it is not particularly clear to those skilled in the art in the context in which they are used and described herein, a quantity having a value of about 1 means that the quantity has a value between 0.95 and 1.05, and that value may be 1.

[0044] All references, patents, or patent applications cited above are incorporated herein by reference in a consistent manner. In the event of any inconsistency or contradiction between any part of an incorporated reference and this application, the information in the preceding description shall prevail.

[0045] Descriptions of elements in the figures should be understood to apply equally to corresponding elements in other figures unless otherwise indicated. While specific embodiments have been illustrated and described herein, it will be understood by those skilled in the art that specific embodiments illustrated and described can be replaced by various alternative and / or equivalent embodiments without departing from the scope of this disclosure. This application is intended to encompass all adaptations or variations of the specific embodiments discussed herein. Therefore, this disclosure is intended to be limited only by the claims and their equivalents. The following are exemplary embodiments. [Item 1] An optical laminate, A reflective polarizer containing multiple interference layers, The system comprises an absorbing polarizer disposed on the reflective polarizer and having substantially the same extent as the reflective polarizer, With respect to substantially normally incident light, and with respect to at least a first wavelength between approximately 450 nm and approximately 670 nm, Each interference layer reflects or transmits light primarily through optical interference. The plurality of interference layers transmit at least about 85% of the incident light having a first polarization state, reflect at least about 80% of the incident light having an orthogonal second polarization state, and transmit less than about 0.1% of the incident light having the second polarization state. The absorptive polarizer has a first light transmittance for the first polarization state, a light absorption rate of more than 50% for the second polarization state, and a second light transmittance for the second polarization state, the average of the first light transmittance and the second light transmittance is more than 0.46, and the second light transmittance has a first standard deviation over at least 80% of the absorptive polarizer. The optical laminate has a light transmittance for a second polarization state, wherein the second standard deviation is at least 80% of the optical laminate, and the second standard deviation is at least about 10% smaller than the first standard deviation. [Item 2] The optical laminate described in item 1, wherein the first wavelength is approximately 550 nm. [Item 3] An optical laminate according to item 1 or 2, wherein each interference layer has an average thickness of less than approximately 500 nm. [Item 4] An optical laminate according to any one of items 1 to 3, wherein the absorbing polarizer is bonded to the reflective polarizer. [Item 5] The optical laminate according to any one of items 1 to 4, wherein the absorbing polarizer is coated on the reflective polarizer. [Item 6] An optical laminate according to any one of items 1 to 5, wherein the first standard deviation is greater than approximately 0.004. [Item 7] An optical laminate according to any one of items 1 to 6, wherein the second standard deviation is less than approximately 0.0001. [Item 8] With regard to virtually perpendicularly incident unpolarized light, and with regard to a first wavelength range of approximately 450 nm to approximately 650 nm, The absorbing polarizer has an averaged light transmittance over the first wavelength range, with a third standard deviation over at least 80% of the absorbing polarizer. The optical laminate according to any one of items 1 to 7, wherein the optical laminate has an averaged light transmittance over the first wavelength range, with a fourth standard deviation over at least 80% of the optical laminate, and the fourth standard deviation is at least about 10% smaller than the third standard deviation. [Item 9] The optical laminate described in item 8, wherein the third standard deviation is greater than approximately 0.005. [Item 10] Display panel and An extended light source configured to supply illumination to the aforementioned display panel, A display comprising: an optical laminate according to any one of items 1 to 9, disposed between the display panel and the extended light source, wherein the absorbing polarizer faces the display panel and the reflective polarizer faces the extended light source. [Item 11] A display panel including an active area configured to display an image, An extended light source configured to supply illumination to the aforementioned display panel, A reflective polarizer is disposed between the display panel and the extended light source, and comprises a total of at least 50 polymer layers, each polymer layer having an average thickness of less than approximately 500 nm. The system comprises an absorptive polarizer disposed between the display panel and the reflective polarizer, The extended light source, the active region of the display panel, the reflective polarizer, and the absorbing polarizer have substantially the same extent to each other. With respect to substantially perpendicularly incident light, and with respect to at least one wavelength between approximately 450 nm and approximately 650 nm, The polarization efficiency of the reflective polarizer across the active region of the display panel has an average of more than approximately 0.995 and a standard deviation of less than approximately 0.001. A display in which the polarization efficiency of the absorbing polarizer across the active region of the display panel has an average of less than approximately 0.93 and a standard deviation of greater than approximately 0.005. [Item 12] The display according to item 11, wherein the standard deviation of the polarization efficiency of the reflective polarizer is less than approximately 0.0005. [Item 13] The display according to item 11 or 12, wherein the standard deviation of the polarization efficiency of the absorptive polarizer is greater than approximately 0.006. [Item 14] The display according to any one of items 11 to 13, wherein the average polarization efficiency of the reflective polarizer is greater than approximately 0.999. [Item 15] The display according to any one of items 11 to 14, wherein the average polarization efficiency of the absorbing polarizer is less than approximately 0.92.

Claims

1. An optical laminate, A reflective polarizer containing multiple interference layers, The system comprises an absorbing polarizer disposed on the reflective polarizer and having the same extent as the reflective polarizer, With respect to normally incident light, and with respect to at least a first wavelength between 450 nm and 670 nm, Each interference layer reflects or transmits light primarily through optical interference. The plurality of interference layers transmit at least 85% of the incident light having a first polarization state, reflect at least 80% of the incident light having an orthogonal second polarization state, and transmit less than 0.1% of the incident light having the second polarization state. The absorbing polarizer has a first light transmittance for the first polarization state, a light absorptance of more than 50% for the second polarization state, and a second light transmittance for the second polarization state, the average of the first light transmittance and the second light transmittance is greater than 0.46, and the second light transmittance has a first standard deviation of less than 0.01 and greater than 0.004 over at least 80% of the absorbing polarizer. The optical laminate has a light transmittance for a second polarization state, wherein the second standard deviation is less than 0.0001 over at least 80% of the optical laminate.

2. The optical laminate according to claim 1, wherein the first wavelength is 550 nm.

3. The optical laminate according to claim 1 or 2, wherein each interference layer has an average thickness of less than 500 nm.

4. The optical laminate according to any one of claims 1 to 3, wherein the absorbing polarizer is bonded to the reflective polarizer.

5. The optical laminate according to any one of claims 1 to 4, wherein the absorbing polarizer is coated on the reflective polarizer.

6. With respect to normally incident unpolarized light, and with respect to a first wavelength range of 450 nm to 650 nm, The absorbing polarizer has an averaged light transmittance over the first wavelength range, with a third standard deviation over at least 80% of the absorbing polarizer. The optical laminate according to any one of claims 1 to 5, wherein the optical laminate has an averaged light transmittance over the first wavelength range, with a fourth standard deviation over at least 80% of the optical laminate, and the fourth standard deviation is at least 10% smaller than the third standard deviation.

7. The optical laminate according to claim 6, wherein the third standard deviation is less than 0.01 and greater than 0.

005.

8. Display panel and An extended light source configured to supply illumination to the aforementioned display panel, A display comprising: an optical laminate according to any one of claims 1 to 7, disposed between the display panel and the extended light source, wherein the absorbing polarizer faces the display panel and the reflective polarizer faces the extended light source.

9. A display panel including an active area configured to display an image, An extended light source configured to supply illumination to the aforementioned display panel, Displaced between the display panel and the extended light source, a reflective polarizer comprising a total of at least 50 polymer layers, each polymer layer having an average thickness of less than 500 nm, The system comprises an absorptive polarizer disposed between the display panel and the reflective polarizer, The extended light source, the active region of the display panel, the reflective polarizer, and the absorbing polarizer have the same extent to each other. With respect to normally incident light, and with respect to at least one wavelength between 450 nm and 650 nm, The polarization efficiency of the reflective polarizer across the active region of the display panel has an average of greater than 0.995 and a standard deviation of less than 0.

001. The polarization efficiency of the absorbing polarizer across the active region of the display panel has an average of less than 0.93 and greater than 0.8, and a standard deviation of less than 0.01 and greater than 0.

005. A display in which the transmittance of the absorbing polarizer to blocked light has a standard deviation of less than 0.01 and greater than 0.004 over at least 80% of the absorbing polarizer.

10. The display according to claim 9, wherein the standard deviation of the polarization efficiency of the reflective polarizer is less than 0.0005.

11. The display according to claim 9 or 10, wherein the standard deviation of the polarization efficiency of the absorbing polarizer is less than 0.01 and greater than 0.

006.

12. The display according to any one of claims 9 to 11, wherein the average polarization efficiency of the reflective polarizer is greater than 0.

999.

13. The display according to any one of claims 9 to 12, wherein the average polarization efficiency of the absorbing polarizer is less than 0.92 and greater than 0.8.

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