Vehicle display system

Abstract

The display system includes a display panel configured to emit polarized light having a first polarization state and substantially different blue, green, and red emission spectra having blue, green, and red full widths at half maximum (FWHM), respectively. The display system includes a reflective polarizer configured to reflect the polarized image light as first reflected polarized image light. For substantially normally incident light and for the first polarization state, the reflective polarizer has a reflectivity greater than about 60% across each of the blue and red FWHMs and a transmittance of at least about 50% for at least a first wavelength between the FWHM of the blue emission spectrum and the FWHM of the green emission spectrum and for at least a second wavelength between the FWHM of the green emission spectrum and the FWHM of the red emission spectrum.

Description

Technical Field

[0001] The present disclosure generally relates to a display system used within a vehicle, and more particularly to a display system for forming and displaying virtual images for viewing by a vehicle passenger.

Background Art

[0002] A head-up display (HUD) is used within a vehicle to present information to a passenger that can be viewed through the vehicle's windshield without the passenger having to look away from the surroundings of the vehicle. The use of HUDs as a safety feature in vehicles such as automobiles is increasing. A typical HUD includes a display and several mirrors for reflecting light emitted from the display towards the passenger.

Summary of the Invention

[0003] In a first aspect, the present disclosure provides a display system for displaying a virtual image to a passenger of a vehicle. The display system includes a display panel, a reflective polarizer, and a mirror. The display panel is configured to emit polarized image light having a first polarization state and substantially different blue, green, and red emission spectra each having a blue, green, and red full width at half maximum (FWHM). The reflective polarizer is configured to receive the polarized image light and reflect it as first reflected polarized image light. The reflective polarizer has a reflection spectrum having substantially different blue, green, and red reflection bands each having a blue, green, and red FWHM. The mirror is configured to receive the first reflected polarized image light and reflect it as second reflected polarized image light toward the front glass of the vehicle, and for substantially normal incident light and for the first polarization state, the reflective polarizer reflects at least about 60% of the incident light for at least one wavelength within each of the FWHMs of the blue, green, and red reflection bands. Further, for the first polarization state, the reflective polarizer transmits at least about 50% of the incident light for at least one same first wavelength between the FWHM of the blue reflection band and the FWHM of the green reflection band and between the FWHM of the blue emission spectrum and the FWHM of the green emission spectrum, and for at least one same second wavelength between the FWHM of the green reflection band and the FWHM of the red reflection band and between the FWHM of the green emission spectrum and the FWHM of the red emission spectrum. For an orthogonal second polarization state, the reflective polarizer transmits at least about 60% of the incident light for each wavelength within the FWHM of the blue reflection band, within the FWHM of the red reflection band, and within the FWHM of the blue emission spectrum, within the FWHM of the red emission spectrum, and for each wavelength between the FWHM of the blue reflection band and the FWHM of the red reflection band and between the FWHM of the blue emission spectrum and the FWHM of the red emission spectrum. Further, for at least the first polarization state, the mirror reflects at least about 70% of the incident light for each wavelength within the FWHMs of the blue, green, and red emission spectra.

[0004] In a second aspect, the present disclosure provides a display system for displaying a virtual image to a passenger of a vehicle. The display system includes a display panel and a reflective polarizer. The display panel is configured to emit polarized light having a first polarization state and substantially different blue, green, and red emission spectra each having a blue, green, and red full width at half maximum (FWHM). The reflective polarizer is configured to receive polarized image light and reflect it as first reflected polarized image light, and the first reflected polarized image light is configured to be reflected toward an observer after reflection at at least a front glass of the vehicle. For substantially normal incident light, the reflective polarizer has an average total reflectance of greater than about 60% over each of the blue FWHM and the red FWHM for the first polarization state, and an average total reflectance of less than about 30% over the green FWHM for the first polarization state. The reflective polarizer further has a transmittance of at least about 50% for the first polarization state for at least a first wavelength between the FWHM of the blue emission spectrum and the FWHM of the green emission spectrum, and for at least a second wavelength between the FWHM of the green emission spectrum and the FWHM of the red emission spectrum. The reflective polarizer further has an average total transmittance of greater than about 70% over a visible wavelength range including at least each of the blue FWHM, the green FWHM, and the red FWHM for a second orthogonal polarization state.

Brief Description of the Drawings

[0005] By considering the following "Modes for Carrying Out the Invention" together with the following figures, the exemplary embodiments disclosed herein can be understood more fully. The figures are not necessarily drawn to scale. Like numbers used in the drawings indicate like components. However, it will be understood that the use of numbers to indicate components in a given figure is not intended to limit the components in another figure indicated by the same number.

[0006]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5A

Figure 5B

Figure 6A

Figure 6B

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Figure 8

DETAILED DESCRIPTION OF THE INVENTION

[0007] In the following description, reference is made to the accompanying drawings which form a part hereof and in which various embodiments are shown by way of illustration. It is to be understood that other embodiments may be envisioned and practiced without departing from the scope or spirit of the present disclosure. Accordingly, the following detailed description of the invention is not to be taken in a limiting sense.

[0008] The present disclosure relates to a display system for forming and displaying a virtual image for a passenger of a vehicle. The display system can be a head-up display (HUD). The display system can be used in various vehicles such as aircraft, ships, or land vehicles (including motor vehicles such as cars, trucks, and motorcycles).

[0009] The display system includes a display panel and a reflective polarizer. The display system may further include a mirror. The display panel emits polarized image light having a first polarization state and substantially different blue, green, and red emission spectra each having a blue, green, and red full width at half maximum (FWHM). The reflective polarizer receives the polarized image light and reflects it as first reflected polarized image light.

[0010] The reflective polarizer has a reflection spectrum having substantially different blue, green, and red reflection bands each having a blue, green, and red FWHM. The mirror receives the first reflected polarized image light and reflects it as a second reflected polarized image toward the front glass of the vehicle, and for substantially normal incident light and for the first polarization state, the reflective polarizer reflects at least about 60% of the incident light for at least one wavelength within each FWHM of the blue, green, and red reflection bands. Further, for the first polarization state, the reflective polarizer transmits at least about 50% of the incident light for at least one same first wavelength between the FWHM of the blue reflection band and the FWHM of the green reflection band and between the FWHM of the blue emission spectrum and the FWHM of the green emission spectrum, and for at least one same second wavelength between the FWHM of the green reflection band and the FWHM of the red reflection band and between the FWHM of the green emission spectrum and the FWHM of the red emission spectrum. For an orthogonal second polarization state, the reflective polarizer transmits at least about 60% of the incident light for each wavelength within the FWHM of the blue reflection band, within the FWHM of the red reflection band, and within the FWHM of the blue emission spectrum, within the FWHM of the red emission spectrum, and for each wavelength between the FWHM of the blue reflection band and the FWHM of the red reflection band and between the FWHM of the blue emission spectrum and the FWHM of the red emission spectrum. Further, for at least the first polarization state, the mirror reflects at least about 70% of the incident light for each wavelength within the FWHM of the blue, green, and red emission spectra.

[0011] Sunlight incident on a display panel of a conventional display system or HUD may cause heat management problems by heating the display panel. In some cases, a cold mirror that reflects sunlight within the visible wavelength range while passing a portion of the sunlight to a heat sink is used in the HUD. However, cold mirrors are generally broadband mirrors. Since a significant amount of solar energy is within the visible wavelength range, cold mirrors still reflect a large amount of solar energy toward the display panel.

[0012] The reflective polarizer of the present disclosure may include a plurality of reflection bands selected based on the emission spectrum of the display panel, and the reflective polarizer transmits most of the incident light in a first polarization state for wavelengths outside the emission spectrum. The reflective polarizer may also substantially transmit the incident light in a second polarization state. For wavelengths outside the emission spectrum, the incident light in the first polarization state may be from an external source (e.g., sunlight) and is not used to generate a virtual image. The incident light in the second polarization state may also be from an external source. The portion of the incident light transmitted by the reflective polarizer may not be received by the display panel. Thus, the reflective polarizer may reduce heating of the display panel by incident light from an external source.

[0013] The reflective polarizer may substantially reflect the incident light for the first polarization state and for wavelengths within the full width at half maximum (FWHM) of each of the blue, green, and red reflection bands. The reflective polarizer may substantially transmit the incident light for the first polarization state and for wavelengths between the FWHM of the blue reflection band and the FWHM of the green reflection band, and between the FWHM of the blue emission spectrum and the FWHM of the green emission spectrum. The reflective polarizer may further substantially transmit the incident light for the first polarization state and for wavelengths between the FWHM of the green reflection band and the FWHM of the red reflection band, and between the FWHM of the green emission spectrum and the FWHM of the red emission spectrum. Thus, the reflective polarizer can improve the heat management of the display panel.

[0014] Furthermore, the reflective polarizer can substantially transmit the incident light for the second polarization state, thereby further improving the thermal management of the display panel.

[0015] Referring now to the figures, FIG. 1 schematically shows a side view of an exemplary vehicle 10 that may implement an exemplary embodiment of the present disclosure. The vehicle 10 may include any passable vehicle that can operate on a road surface, including, but not limited to, passenger cars, buses, motorcycles, off-road vehicles, and trucks. In some other embodiments, the vehicle 10 may also include watercraft and aircraft. The vehicle 10 includes a windshield 50. The windshield 50 may include any of a wide variety of transparent members, may be integral or laminated, may be flat or curved (simple curvature or compound curvature), may be colorless and transparent or colored, may have focusing characteristics (e.g., in the case of goggles or other eyewear), and may be composed of any conventional glass and / or plastic. In some instances, the windshield 50 may include a sheet of glass or other transparent material having two surfaces facing opposite each other.

[0016] FIG. 2 shows a display system 300 for displaying the virtual image 12 to the passenger 11 of the vehicle 10 (shown in FIG. 1). The display system 300 includes a display panel 20 and a reflective polarizer 30. In the illustrated embodiment of FIG. 2, the display system 300 further includes a mirror 40. In some embodiments, the display system 300 is a HUD. The display system 300 displays information to the passenger 11 of the vehicle 10. The passenger 11 may be the driver of the vehicle 10. The display system 300 displays the information within the driver's field of view so that the driver does not have to look away from the front windshield 50 during driving to view the displayed information. The display system 300 of the vehicle 10 disclosed in the present disclosure may be configured to display on the front windshield 50 of the vehicle 10 any type of information such as map-related information, navigation instructions, a certain type of warning or alert, automated driving assistance information, vehicle speed, fuel level, engine temperature, communication events, and other related information, but is not limited thereto. The display of such information on the front windshield 50 of the vehicle 10 may also be presented in any form such as digital gauges, text boxes, animated images, or any other graphic representation, but is not limited thereto. Further, the display system 300 of the vehicle 10 may also present augmented reality graphic elements that extend the physical environment surrounding the vehicle 10 using real-time information.

[0017] The display panel 20 may include various elements such as an electroluminescence panel, an incandescent light source or a phosphorescent light source, a cathode ray tube (CRT), a light emitting diode (LED), a lens, a collimator, a reflector, and / or a polarizer. In some embodiments, the display panel 20 may include an organic light emitting diode (OLED) display panel. In some other embodiments, the display panel 20 may include a liquid crystal display (LCD) panel. The virtual image 12 may be substantially monochromatic, multicolor, narrowband, or broadband, but preferably overlaps at least a part of the visible spectrum. Further, the display panel 20 may also include a mechanism such as a tiltable mirror or displacement means for changing the angle and / or position of the virtual image 12 so as to accommodate passengers 11 at different locations or heights.

[0018] Referring to FIGS. 1, 2, and 7, the display panel 20 is configured to emit polarized image light 21 having a first polarization state and substantially different blue spectrum 22b, green spectrum 22g, and red emission spectrum 22r having blue FWHM Wb, green FWHM Wg, and red FWHM Wr, respectively.

[0019] The reflective polarizer 30 is configured to receive the polarized image light 21 and reflect it as first reflected polarized image light 22. The reflective polarizer 30 may be a notch reflective polarizer having a plurality of notches or bands. The reflective polarizer 30 has a reflection spectrum 31x for the first polarization state. The reflection spectrum 31x has substantially different blue reflection band Rb, green reflection band Rg, and red reflection band Rr having blue FWHM 32b, green FWHM 32g, and red FWHM 32r, respectively. The reflective polarizer 30 has a reflection spectrum 31y for a second polarization state orthogonal to the first polarization state. In some other embodiments, the first polarization state is a P polarization state, while the second polarization state is an S polarization state. In some other embodiments, the first polarization state is an S polarization state, while the second polarization state is a P polarization state.

[0020] The first reflected polarized image light 22 is configured to be reflected toward the passenger 11 after being reflected at least by the front glass 50 of the vehicle 10. In some embodiments, the front glass 50 is configured to receive the second reflected polarized image light 23 and reflect 5% to 40% thereof as the third reflected polarized image light 27 toward the passenger 11 of the vehicle 10. In the illustrated embodiment of FIG. 2, the mirror 40 is configured to receive the first reflected polarized image light 22 and reflect it toward the front glass 50 of the vehicle 10 as the second reflected polarized image 23.

[0021] FIG. 3 shows a schematic view of the display panel 20 of the display system 300 shown in FIG. 2. The display panel 20 includes a plurality of blue pixels 26b, green pixels 26g, and red pixels 26r. The plurality of blue pixels 26b, green pixels 26g, and red pixels 26r are configured to emit polarized image light 21 having a first polarization state. The light emitted by the plurality of blue pixels 26b, green pixels 26g, and red pixels 26r has a blue emission spectrum 22b, a green emission spectrum 22g, and a red emission spectrum 22r, respectively (shown in FIG. 7).

[0022] FIG. 4 shows a detailed schematic view of a reflective polarizer 30 according to an embodiment of the present disclosure. The reflective polarizer 30 defines an x-axis, a y-axis, and a z-axis that are orthogonal to each other. The x-axis and the y-axis are in-plane axes of the reflective polarizer 30, while the z-axis is a transverse axis arranged along the thickness of the reflective polarizer 30. In other words, the x-axis and the y-axis are arranged along the plane of the reflective polarizer 30, while the z-axis is perpendicular to the plane of the reflective polarizer 30. The first polarization state is defined along the x-axis, while the second polarization state is defined along the y-axis.

[0023] As shown in FIG. 4, the reflective polarizer 30 includes a plurality of alternating first polymer layers 33 and second polymer layers 34. In some embodiments, the plurality of alternating first polymer layers 33 and second polymer layers 34 total at least 40. In some other embodiments, the plurality of alternating first polymer layers 33 and second polymer layers 34 total at least 50.

[0024] In some embodiments, each of the alternating first polymer layers 33 and second polymer layers 34 has an average thickness of less than about 350 nm. In some embodiments, each of the alternating first polymer layers 33 and second polymer layers 34 has an average thickness of less than about 400 nm or less than about 500 nm.

[0025] FIG. 5A shows a schematic diagram of a reflective polarizer 30 according to an embodiment of the present disclosure. In some embodiments, the reflective polarizer 30 is curved. Referring to FIGS. 2, 5A, and 7, for substantially vertically incident light 60 and for a first polarization state, the reflective polarizer 30 reflects at least about 60% of the incident light 60 for at least one wavelength 24b, 24g, 24r within each of the full-width at half-maximum (FWHM) 32b of the blue reflection band Rb, the FWHM 32g of the green reflection band Rg, and the FWHM 32r of the red reflection band Rr. The wavelengths 24b, 24g, 24r are within the FWHM 32b of the blue reflection band Rb, the FWHM 32g of the green reflection band Rg, and the FWHM 32r of the red reflection band Rr, respectively. Thus, the reflective polarizer 30 reflects at least 60% of the incident light 60 for at least one wavelength 24b within the blue FWHM 32b of the blue reflection band Rb. The reflective polarizer 30 further reflects at least 60% of the incident light 60 for at least one wavelength 24g within the green FWHM 32g of the green reflection band Rg. The reflective polarizer 30 further reflects at least 60% of the incident light 60 for at least one wavelength 24r within the red FWHM 32r of the red reflection band Rr. In some embodiments, the reflective polarizer 30 reflects at least about 70%, at least about 75%, at least about 80%, or at least about 85% of the incident light 60 for at least one wavelength 24b, 24g, 24r within each of the FWHM 32b of the blue reflection band Rb, the FWHM 32g of the green reflection band Rg, and the FWHM 32r of the red reflection band Rr.

[0026] In some embodiments, for substantially vertically incident light 60, the reflective polarizer 30 has an average total reflectance of greater than about 60% across each of the blue FWHM 32b and the red FWHM 32r for a first polarization state, and an average total reflectance of less than about 30% across the green FWHM 32g for the first polarization state.

[0027] In some embodiments, for substantially normal incident light 60 and for a first polarization state, the reflective polarizer 30 transmits at least about 50% of the incident light 60 for at least one same first wavelength 25bg between the FWHM 32b of the blue reflection band Rb and the FWHM 32g of the green reflection band Rg and between the FWHM Wb of the blue emission spectrum 22b and the FWHM Wg of the green emission spectrum 22g, and for at least one same second wavelength 25gr between the FWHM 32g of the green reflection band Rg and the FWHM 32r of the red reflection band Rr and between the FWHM Wg of the green emission spectrum 22g and the FWHM Wr of the red emission spectrum 22r. The first wavelength 25bg is between the FWHM 32b of the blue reflection band Rb and the FWHM 32g of the green reflection band Rg and between the FWHM Wb of the blue emission spectrum 22b and the FWHM Wg of the green emission spectrum 22g. The second wavelength 25gr is between the FWHM 32g of the green reflection band Rg and the FWHM 32r of the red reflection band Rr and between the FWHM Wg of the green emission spectrum 22g and the FWHM Wr of the red emission spectrum 22r. In some embodiments, the reflective polarizer 30 transmits at least about 55%, at least about 60%, or at least about 65% of the incident light 60 for at least one same first wavelength 25bg between the FWHM 32b of the blue reflection band Rb and the FWHM 32g of the green reflection band Rg and between the FWHM Wb of the blue emission spectrum 22b and the FWHM Wg of the green emission spectrum 22g, and for at least one same second wavelength 25gr between the FWHM 32g of the green reflection band Rg and the FWHM 32r of the red reflection band Rr and between the FWHM Wg of the green emission spectrum 22g and the FWHM Wr of the red emission spectrum 22r.

[0028] In some embodiments, for substantially normal incident light 60, the reflective polarizer 30 has a transmittance of at least about 50% for at least a first wavelength 25bg between the FWHM Wb of the blue emission spectrum 22b and the FWHM Wg of the green emission spectrum 22g, and for at least a second wavelength 25gr between the FWHM Wg of the green emission spectrum 22g and the FWHM Wr of the red emission spectrum 22r, for the first polarization state. In some embodiments, for substantially normal incident light 60, the reflective polarizer 30 has a transmittance of at least about 55%, at least about 60%, or at least about 65% for at least a first wavelength 25bg between the FWHM Wb of the blue emission spectrum 22b and the FWHM Wg of the green emission spectrum 22g, and for at least a second wavelength 25gr between the FWHM Wg of the green emission spectrum 22g and the FWHM Wr of the red emission spectrum 22r, for the first polarization state.

[0029] For the second polarization state, the reflective polarizer 30 transmits at least about 60% of the incident light 60 for each wavelength within the FWHM 32b of the blue reflection band Rb, the FWHM 32r of the red reflection band Rr, and the FWHM Wb of the blue emission spectrum 22b and the FWHM Wr of the red emission spectrum 22r, and for each wavelength therebetween. In other words, the reflective polarizer 30 transmits at least about 60% of the incident light 60 for each wavelength within the FWHM 32b of the blue reflection band Rb and the FWHM 32r of the red reflection band Rr, and for each wavelength between the FWHM 32b and the FWHM 32r. The reflective polarizer 30 further transmits at least about 60% of the incident light 60 for each wavelength within the FWHM Wb of the emission spectrum 22b and the FWHM Wr of the emission spectrum 22r, and for each wavelength between the FWHM Wb and the FWHM Wr. In some embodiments, for the second polarization state, the reflective polarizer 30 may transmit at least about 60% of the incident light 60 for each wavelength within the visible wavelength range of about 400 nanometers (nm) to about 700 nm.

[0030] In some embodiments, for the second polarization state, the reflective polarizer 30 transmits at least about 70%, at least about 80%, or at least about 85% of the incident light 60 for each wavelength within the FWHM 32b of the blue reflection band Rb, the FWHM 32r of the red reflection band Rr, and the FWHM Wb of the blue emission spectrum 22b, the FWHM Wr of the red emission spectrum 22r, and for each wavelength therebetween.

[0031] In some embodiments, for substantially normal incident light 60, for the second polarization state, the reflective polarizer 30 has an average total transmittance of greater than about 70% over the visible wavelength range including the blue FWHM 32b, the green FWHM 32g, and the red FWHM 32r.

[0032] The reflective polarizer 30 can substantially reflect the incident light (e.g., at least 60% of the incident light) for each wavelength within the FWHM 32b of the blue reflection band Rb, the FWHM 32g of the green reflection band Rg, and the FWHM 32r of the red reflection band Rr for the first polarization state. The reflective polarizer 30 can further substantially transmit the incident light (e.g., at least 50% of the incident light) for wavelengths between the FWHM 32b of the blue reflection band Rb and the FWHM 32g of the green reflection band Rg, and further for wavelengths between the FWHM Wb of the blue emission spectrum 22b and the FWHM Wg of the green emission spectrum 22g for the first polarization state. The reflective polarizer 30 can further substantially transmit the incident light (e.g., at least 50% of the incident light) for wavelengths between the FWHM 32g of the green reflection band Rg and the FWHM 32r of the red reflection band Rr, and further for wavelengths between the FWHM Wg of the green emission spectrum 22g and the FWHM Wr of the red emission spectrum 22r for the first polarization state. Thus, the reflective polarizer can improve the thermal management of the display panel 20.

[0033] In addition, the reflective polarizer 30 substantially transmits the incident light (at least 60% of the incident light) for the second polarization state, thereby further improving the thermal management of the display panel 20.

[0034] In addition, the reflective polarizer 30 substantially transmits the incident light 60 having the second polarization state, thereby further improving the thermal management of the display panel 20.

[0035] FIG. 5B shows a schematic view of the mirror 40 according to an embodiment of the present disclosure. In some embodiments, the mirror 40 is curved. Referring now to FIGS. 2, 5B, and 7, for substantially normal incident light 61, at least for the first polarization state, the mirror 40 reflects at least about 70% of the incident light 61 for each wavelength within the full width at half maximum (FWHM) Wb of the blue emission spectrum 22b, the FWHM Wg of the green emission spectrum 22g, and the FWHM Wr of the red emission spectrum 22r. In other words, at least for the first polarization state, the mirror 40 reflects at least about 70% of the incident light 61 for each wavelength within the blue FWHM Wb, the green FWHM Wg, and the red FWHM Wr.

[0036] In some embodiments, for substantially normal incident light 61, at least for the first polarization state, the mirror 40 reflects at least about 80%, or at least about 90% of the incident light 61 for each wavelength within the full width at half maximum (FWHM) Wb of the blue emission spectrum 22b, the FWHM Wg of the green emission spectrum 22g, and the FWHM Wr of the red emission spectrum 22r.

[0037] In some embodiments, for each of the first and second polarization states, mirror 40 reflects at least about 70% of the incident light 61 for each wavelength within the full width at half maximum (FWHM) 32b of the blue reflection band Rb, the FWHM 32r of the red reflection band Rr, the FWHM Wb of the blue emission spectrum 22b, the FWHM Wr of the red emission spectrum 22r, and for each wavelength therebetween. In other words, for each of the first and second polarization states, mirror 40 reflects at least about 70% of the incident light 61 for each wavelength within the FWHM 32b of the blue reflection band Rb and the FWHM 32r of the red reflection band Rr, and further for each wavelength between the FWHM 32b and the FWHM 32r. For each of the first and second polarization states, mirror 40 further reflects at least about 70% of the incident light 61 for each wavelength within the FWHM Wb of the emission spectrum 22b and the FWHM Wr of the emission spectrum 22r, and further for each wavelength between the FWHM Wb and the FWHM Wr.

[0038] In some embodiments, for each of the first and second polarization states, mirror 40 reflects at least about 80%, or at least about 90% of the incident light 61 for each wavelength within the full width at half maximum (FWHM) 32b of the blue reflection band Rb, the FWHM 32r of the red reflection band Rr, the FWHM Wb of the blue emission spectrum 22b, the FWHM Wr of the red emission spectrum 22r, and for each wavelength therebetween.

[0039] In some embodiments, for each of the first and second polarization states, mirror 40 may reflect at least about 70% of the incident light 61 for each wavelength within the visible wavelength range of about 400 nm to about 700 nm.

[0040] FIG. 6A shows a schematic view of a curved reflective polarizer 30'. The curved reflective polarizer 30' may be concave. In some other embodiments, the curved reflective polarizer 30' may be convex.

[0041] FIG. 6B shows a schematic view of a curved mirror 40'. The curved mirror 40' may be concave. In some other embodiments, the curved mirror 40' may be convex.

[0042] In some embodiments, the display system 300 (shown in FIG. 2) includes at least one of a curved reflective polarizer 30' and a curved mirror 40'. In some embodiments, the display system 300 includes the curved reflective polarizer 30'. In another embodiment, the display system 300 includes the curved mirror 40'. In some other examples, the display system 300 includes both the curved reflective polarizer 30' and the curved mirror 40'.

[0043] FIGS. 7 and 8 show graphs 700, 800 that illustrate the wavelength-dependent variation of the transmittance of incident light 60 (shown in FIG. 5A) for a reflective polarizer 30 (shown in FIG. 2). The wavelength is expressed in nanometers (nm) over the visible wavelength range. The transmittance is represented as a transmittance percentage on the left vertical axis, and the reflectance is represented as a reflectance percentage on the right vertical axis. The reflectance is complementary to the transmittance, i.e., reflectance = (100 - transmittance). Graphs 700, 800 show the reflection spectra 31x of the reflective polarizer 30 for a first polarization state and the reflection spectra 31y of the reflective polarizer 30 for a second polarization state. The reflection spectrum 31x for the first polarization state includes a blue reflection band Rb, a green reflection band Rg, and a red reflection band Rr, each having a blue FWHM 32b, a green FWHM 32g, and a red FWHM 32r, respectively.

[0044] Graphs 700, 800 further show a blue emission spectrum 22b, a green emission spectrum 22g, and a red emission spectrum 22r of polarized image light 21 emitted by the display panel 20 (shown in FIG. 2), each having a blue FWHM Wb, a green FWHM Wg, and a red FWHM Wr, respectively. The emission spectrum of the display panel 20 can be shown in graphs 700, 800 using any suitable energy unit.

[0045] Graphs 700 and 800 show wavelength 24b within blue FWHM 32b of blue reflection band Rb, wavelength 24g within green FWHM 32g of green reflection band Rg, and wavelength 24r within red FWHM 32r of red reflection band Rr.

[0046] Graphs 700 and 800 further show a first wavelength 25bg and a second wavelength 25gr. The first wavelength 25bg is between FWHM 32b of blue reflection band Rb and FWHM 32g of green reflection band Rg, and between FWHM Wb of blue emission spectrum 22b and FWHM Wg of green emission spectrum 22g. The second wavelength 25gr is between FWHM 32g of green reflection band Rg and FWHM 32r of red reflection band Rr, and between FWHM Wg of green emission spectrum 22g and FWHM Wr of red emission spectrum 22r.

[0047] In some embodiments, at least about 40% of FWHM Wb of blue emission spectrum 22b and FWHM Wr of red emission spectrum 22r overlap with blue FWHM 32b of reflection band Rb and red FWHM 32r of reflection band Rr, respectively. In some embodiments, at least about 50%, at least about 60%, at least about 70%, at least about 80%, or at least about 90% of FWHM Wb of blue emission spectrum 22b and FWHM Wr of red emission spectrum 22r overlap with blue FWHM 32b of reflection band Rb and red FWHM 32r of reflection band Rr, respectively.

[0048] As shown in graph 700, at least about 80% of FWHM Wb of blue emission spectrum 22b and FWHM Wr of red emission spectrum 22r overlap with blue FWHM 32b of reflection band Rb and red FWHM 32r of reflection band Rr, respectively. Further, in some embodiments, at most about 20% of FWHM Wg of green emission spectrum 22g overlaps with green FWHM 32g of green reflection band Rg. In some other embodiments, at most about 10% of FWHM Wg of green emission spectrum 22g overlaps with green FWHM 32g of green reflection band Rg.

[0049] As shown in FIG. 7, the blue reflection band Rb and the red reflection band Rr of the reflective polarizer 30 can be substantially aligned with the blue emission spectrum 22b and the red emission spectrum 22g of the display panel 20 (shown in FIG. 2) of the display system 300, respectively. However, the green reflection band Rg may not be aligned with the green emission spectrum 22g. Thereby, for the wavelength of the green emission spectrum 22g, the reflection of the incident light 60 toward the display panel 20 can be further reduced. Thereby, the thermal management of the display panel 20 can be further improved.

[0050] Referring to FIG. 8, at least about 40% of the FWHM Wb of the blue emission spectrum 22b and the FWHM Wr of the red emission spectrum 22g overlap with the blue FWHM 32b of the reflection band Rb and the red FWHM 32g of the reflection band Rg, respectively.

[0051] In the illustrated embodiment of FIG. 8, compared with the graph 700 of FIG. 7, the overlap between the FWHM Wg of the green emission spectrum 22g and the green FWHM 32g of the reflection band Rg is increased. In some embodiments, at least about 40% of the FWHM Wg of the green emission spectrum 22g overlaps with the green FWHM 32g of the green reflection band Rg. In some other embodiments, at least about 50%, at least about 70%, or at least about 80% of the FWHM Wg of the green emission spectrum 22g overlaps with the green FWHM 32g of the green reflection band Rg. Further, compared with the graph 700 of FIG. 7, the overlap between the FWHM Wr of the red emission spectrum 22r and the red FWHM 32r of the reflection band Rr is decreased.

[0052] Furthermore, as shown in FIG. 8, the blue reflection band Rb, the green reflection band Rg, and the red reflection band Rr of the reflective polarizer 30 are aligned with the blue emission spectrum 22b, the green emission spectrum 22g, and the red emission spectrum 22r of the display panel 20 (shown in FIG. 2) of the display system 300 to different extents.

[0053] Unless otherwise indicated, all numbers expressing feature sizes, amounts, and physical properties used in this specification and the claims are to be understood as being modified by the term "about." Accordingly, unless specifically indicated to the contrary, the numerical parameters set forth in the foregoing specification and attached claims are approximations that may vary depending upon the desired properties sought to be obtained by those skilled in the art using the teachings disclosed herein.

[0054] Although specific embodiments have been illustrated and described herein, it will be understood by those of ordinary skill in the art that various alternative and / or equivalent embodiments may 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 of the specific embodiments discussed herein. Accordingly, it is intended that the present disclosure be limited only by the claims and the equivalents thereof. The following shows exemplary embodiments. [Item 1] A display system for displaying a virtual image to a passenger of a vehicle, a display panel configured to emit polarized image light having a first polarization state and substantially different blue, green, and red emission spectra each having a blue, green, and red full width at half maximum (FWHM); a reflective polarizer configured to receive the polarized image light and reflect it as first reflected polarized image light, the reflective polarizer having a reflection spectrum including substantially different blue, green, and red reflection bands each having a blue, green, and red FWHM; a mirror configured to receive the first reflected polarized image light and reflect it as second reflected polarized image light toward a windshield of the vehicle; comprising, for substantially normal incident light, for the first polarization state, the reflective polarizer reflecting at least about 60% of the incident light for at least one wavelength within each of the FWHMs of the blue reflection band, the green reflection band, and the red reflection band; for the first polarization state, the reflective polarizer transmitting at least about 50% of the incident light for at least one same first wavelength between the FWHM of the blue reflection band and the FWHM of the green reflection band and between the FWHM of the blue emission spectrum and the FWHM of the green emission spectrum, and for at least one same second wavelength between the FWHM of the green reflection band and the FWHM of the red reflection band and between the FWHM of the green emission spectrum and the FWHM of the red emission spectrum; for a second orthogonal polarization state, the reflective polarizer transmitting at least about 60% of the incident light for each wavelength within the FWHM of the blue reflection band, within the FWHM of the red reflection band, within the FWHM of the blue emission spectrum, and within the FWHM of the red emission spectrum, and for each wavelength between the FWHM of the blue reflection band and the FWHM of the red reflection band and between the FWHM of the blue emission spectrum and the FWHM of the red emission spectrum. For at least the first polarization state, the mirror reflects at least about 70% of the incident light for each wavelength within the FWHM of the blue emission spectrum, the green emission spectrum, and the red emission spectrum. Display system. [Item 2] The display panel includes a plurality of blue, green, and red pixels configured to emit the polarized image light having the first polarization state, and the light emitted by the blue, green, and red pixels has blue, green, and red emission spectra, respectively. The display system according to Item 1. [Item 3] At least about 40% of the FWHM of the blue emission spectrum and at least about 40% of the FWHM of the red emission spectrum overlap with the blue FWHM of the reflection band and the red FWHM of the reflection band, respectively. The display system according to Item 1. [Item 4] At least about 40% of the FWHM of the green emission spectrum overlaps with the green FWHM of the reflection band. The display system according to Item 1. [Item 5] At most about 20% of the FWHM of the green emission spectrum overlaps with the green FWHM of the green reflection band. The display system according to Item 1. [Item 6] The display panel includes an organic light emitting diode (OLED) display panel. The display system according to Item 1. [Item 7] The front glass is configured to receive the second reflected polarized image light and reflect 5% - 40% of the second reflected polarized image light as the third reflected polarized image light toward the passenger of the vehicle. The display system according to Item 1. [Item 8] For each of the first polarization state and the second polarization state, the mirror reflects at least about 70% of the incident light for each wavelength within the FWHM of the blue reflection band, the FWHM of the red reflection band, and the FWHM of the blue emission spectrum, the FWHM of the red emission spectrum, and also for each wavelength between the FWHM of the blue reflection band and the FWHM of the red reflection band, and between the FWHM of the blue emission spectrum and the FWHM of the red emission spectrum. The display system according to Item 1. [Item 9] The display system according to item 1, wherein the reflective polarizer includes a plurality of alternating first polymer layers and second polymer layers that in total reach at least 40, and each of the first polymer layer and the second polymer layer has an average thickness of less than about 350 nm. [Item 10] A display system for displaying a virtual image to a passenger of a vehicle, a display panel configured to emit polarized image light having a first polarization state and substantially different blue, green, and red emission spectra each having a blue, green, and red full width at half maximum (FWHM), a reflective polarizer configured to receive the polarized image light and reflect it as first reflected polarized image light, wherein the first reflected polarized image light is configured to be reflected toward an observer after reflection at at least a front glass of the vehicle, and for substantially normal incident light, the reflective polarizer has an average total reflectance of more than about 60% over each of the blue FWHM and the red FWHM for the first polarization state, and has an average total reflectance of less than about 30% over the green FWHM for the first polarization state, has a transmittance of at least about 50% for the first polarization state for at least a first wavelength between the FWHM of the blue emission spectrum and the FWHM of the green emission spectrum and for at least a second wavelength between the FWHM of the green emission spectrum and the FWHM of the red emission spectrum, has an average total transmittance of more than about 70% over the visible wavelength range including at least each of the blue FWHM, the green FWHM, and the red FWHM for a second orthogonal polarization state, a display system.

Claims

【Claim 1】 A display system for displaying a virtual image to a passenger of a vehicle, comprising: A display panel configured to emit polarized image light having a first polarization state and substantially different blue, green, and red emission spectra each having a blue, green, and red full width at half maximum (FWHM); A reflective polarizer configured to receive the polarized image light and reflect it as first reflected polarized image light, the reflective polarizer having a reflection spectrum including substantially different blue, green, and red reflection bands each having a blue, green, and red FWHM; A mirror configured to receive the first reflected polarized image light and reflect it as second reflected polarized image light toward a windshield of the vehicle; With respect to substantially normal incident light, For the first polarization state, the reflective polarizer reflects at least about 60% of the incident light for at least one wavelength within each of the FWHMs of the blue reflection band, the green reflection band, and the red reflection band; For the first polarization state, the reflective polarizer transmits at least about 50% of the incident light for at least a first wavelength and a second wavelength, the first wavelength being between the FWHM of the blue reflection band and the FWHM of the green reflection band and between the FWHM of the blue emission spectrum and the FWHM of the green emission spectrum, and the second wavelength being between the FWHM of the green reflection band and the FWHM of the red reflection band and between the FWHM of the green emission spectrum and the FWHM of the red emission spectrum; For a second orthogonal polarization state, the reflective polarizer transmits at least about 60% of the incident light for each wavelength inside each of the FWHMs of the blue reflection band, the red reflection band, the blue emission spectrum, and the red emission spectrum, and for each wavelength between the FWHM of the blue reflection band and the FWHM of the red reflection band and between the FWHM of the blue emission spectrum and the FWHM of the red emission spectrum; For at least the first polarization state, the mirror reflects at least about 70% of the incident light for each wavelength within the FWHMs of the blue emission spectrum, the green emission spectrum, and the red emission spectrum. At most about 20% of the FWHM of the green emission spectrum overlaps with the green FWHM of the green reflection band. Display system. **Claim 2** The display panel includes a plurality of blue, green, and red pixels configured to emit the polarized image light having the first polarization state, and the light emitted by the blue, green, and red pixels has blue, green, and red emission spectra, respectively. The display system according to claim 1. **Claim 3** At least about 40% of the FWHM of the blue emission spectrum and at least about 40% of the FWHM of the red emission spectrum overlap with the FWHM of the blue reflection band and the FWHM of the red reflection band, respectively. The display system according to claim 1. **Claim 4** At least about 40% of the FWHM of the green emission spectrum overlaps with the green FWHM of the reflection band. The display system according to claim 1. **Claim 5** The display panel includes an organic light emitting diode (OLED) display panel. The display system according to claim 1. **Claim 6** The front glass is configured to receive the second reflected polarized image light and reflect 5% to 40% of the second reflected polarized image light as the third reflected polarized image light toward the passenger of the vehicle. The display system according to claim 1. **Claim 7** For each of the first polarization state and the second polarization state, the mirror reflects at least about 70% of the incident light for each wavelength within the FWHM of the blue reflection band, within the FWHM of the red reflection band, within the FWHM of the blue emission spectrum, within the FWHM of the red emission spectrum, and for each wavelength between the FWHM of the blue reflection band and the FWHM of the red reflection band and between the FWHM of the blue emission spectrum and the FWHM of the red emission spectrum. The display system according to claim 1. **Claim 8** The reflective polarizer includes a plurality of alternating first polymer layers and second polymer layers that total at least 40, and each of the first polymer layers and the second polymer layers has an average thickness of less than about 350 nm. The display system according to claim 1. **Claim 9** A display system for displaying a virtual image to a passenger of a vehicle, a display panel configured to emit polarized image light having a first polarization state and substantially different blue, green, and red emission spectra each having a blue, green, and red full width at half maximum (FWHM), a reflective polarizer configured to receive the polarized image light and reflect it as first reflected polarized image light, wherein the first reflected polarized image light is configured to be reflected toward an observer after reflection at at least a front glass of the vehicle, and for substantially normal incident light, the reflective polarizer has an average total reflectance of more than about 60% over each of the blue FWHM and the red FWHM for the first polarization state, and has an average total reflectance of less than about 30% over the green FWHM for the first polarization state, has a transmittance of at least about 50% at least at a first wavelength and a second wavelength for the first polarization state, the first wavelength being between the FWHM of the blue emission spectrum and the FWHM of the green emission spectrum, and the second wavelength being between the FWHM of the green emission spectrum and the FWHM of the red emission spectrum, has an average total transmittance of more than about 70% over a visible wavelength range including at least each of the blue FWHM, the green FWHM, and the red FWHM for a second orthogonal polarization state, a display system.

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