Light-transmitting resin sheet, projection-type display, and moving object

Abstract

This light-transmitting resin sheet is used in a light-transmitting cover member (1) capable of transmitting light, and is provided with a polarizing layer (2) and protective layers (3A, 3B), and when the moisture content in the light-transmitting resin sheet is A [%] and the total thickness of the two protective layers (3A, 3B) is B [mm], the thickness of the polarizing layer (2) is A [%], and the thickness of the protective layers (3A, 3B) is B [mm]. When the translucent resin sheet is stored for 23 hours under the conditions of a temperature of 25 DEG C and a humidity of 50% Rh, the relational expression A * B (1) [mm *%] of the product of the content A and the total thickness B satisfies the relationship 0.20 < = A * B (1) < = 0.70.

Description

Technical Field

[0001] The present invention relates to a light-transmitting resin sheet, a projection type display and a moving body. Background Art

[0002] In recent years, as a projection type display mounted on a moving body such as an automobile for use, a head-up display device is known (for example, refer to Patent Document 1).

[0003] The head-up display device described in Patent Document 1 is a device that obtains a virtual image by reflecting a display image displayed on a display device (display unit) such as a liquid crystal display or a CRT by a reflector and projecting the reflected image onto a windshield glass having a curved screen provided in a vehicle. In the head-up display device, a housing that accommodates the display unit is provided in an instrument panel, and an exit window that emits the displayed image is formed in the housing.

[0004] In addition, the following scheme has been proposed: a translucent cover component (translucent resin sheet) having a polarizing layer composed of a polarizer for generating polarized light and a protective layer mainly composed of a resin material stacked on both sides of the polarizing layer is arranged (installed) on the exit window (for example, refer to Patent Document 2).

[0005] Then, the light-transmitting cover member of this configuration is punched out in accordance with the shape of the exit window provided in the housing, and then attached to the exit window in a bent state in which the cover member is bent so as to form a recessed portion in the center.

[0006] However, there is a problem that cracks may be generated in the light-transmitting cover member when the light-transmitting cover member is punched out to correspond to the shape of the exit window of the light-transmitting cover member or when the light-transmitting cover member is bent to form a recessed portion in the center portion.

[0007] Furthermore, the head-up display device forming this structure is arranged in the instrument panel. Therefore, in particular, in summer, since the instrument panel is exposed to high temperature, the light-transmitting cover member changes color, and as a result, there is a problem that the projection image (virtual image) formed on the screen (windshield) is projected onto the screen as a color tone different from the designed color tone.

[0008] Prior art literature

[0009] Patent Literature

[0010] Patent Document 1: Japanese Patent Application Publication No. 2015-49464;

[0011] Patent document 2: Japanese Patent Application Publication No. 2015-55679. Summary of the invention

[0012] Problems to be solved by the invention

[0013] The object of the present invention is to provide a light-transmitting resin sheet that can accurately suppress or prevent the occurrence of cracks even when punched into a specified shape or further deformed into a curved shape, and can accurately suppress or prevent discoloration even when exposed to high temperatures, and a projection display and a movable body having excellent reliability with the light-transmitting resin sheet.

[0014] Technical solutions to problems

[0015] Such an object is achieved by the present invention described in the following (1) to (11).

[0016] (1) A light-transmitting resin sheet used for a light-transmitting cover member capable of transmitting light, the light-transmitting resin sheet comprising:

[0017] a polarizing layer composed of a polarizer for generating polarized light of the light; and

[0018] The protective layers are respectively arranged on the two sides of the polarizing layer and are mainly composed of a resin material.

[0019] When the water content in the light-transmitting resin sheet is represented by A [%] and the total thickness of the two protective layers provided on both sides of the polarizing layer is represented by B [mm],

[0020] When the translucent resin sheet is stored at a temperature of 25° C. and a humidity of 50% Rh for 23 hours, the relationship A·B(1) [mm·%] of the product of the content A and the total thickness B satisfies the relationship of 0.20≤A·B(1)≤0.70.

[0021] (2) The light-transmitting resin sheet according to (1) above, wherein

[0022] When the translucent resin sheet is stored at a temperature of 35° C. and a humidity of 20% Rh for 22 hours, the relationship A·B(2) [mm·%] of the product of the content A and the total thickness B satisfies the relationship 0.10≤A·B(2)≤0.42.

[0023] (3) The light-transmitting resin sheet according to (1) or (2), wherein

[0024] After the light-transmitting resin sheet was stored under conditions of a temperature of 105° C. and a humidity of 0% Rh for 1000 hours, the color change of the light-transmitting resin sheet measured in accordance with ISO11664-4 satisfied ΔE of less than 13.5.

[0025] (4) The light-transmitting resin sheet according to any one of (1) to (3), wherein

[0026] The protective layer is a single layer mainly composed of the resin material.

[0027] The resin material is a polycarbonate resin.

[0028] (5) The light-transmitting resin sheet according to any one of (1) to (4) above, wherein

[0029] The polarizing layer has a thickness of 5 μm or more and 60 μm or less.

[0030] (6) The light-transmitting resin sheet according to any one of (1) to (5), wherein

[0031] The protective layer has a thickness of 0.07 mm or more and 0.80 mm or less.

[0032] (7) The light-transmitting resin sheet according to any one of (1) to (6), wherein

[0033] The protective layer and the polarizing layer are bonded via a bonding layer.

[0034] (8) The light-transmitting resin sheet according to (7) above, wherein

[0035] The thickness of the bonding layer is greater than or equal to 0.005 mm and less than or equal to 0.04 mm.

[0036] (9) The light-transmitting resin sheet according to any one of (1) to (8), wherein

[0037] The light-transmitting resin sheet is used as the light-transmitting cover member that transmits light emitted from the projection display.

[0038] (10) A projection type display, comprising the light-transmitting resin sheet described in (9) above as the light-transmitting cover member.

[0039] (11) A mobile object comprising the projection display as described in (10) above.

[0040] Effects of the Invention

[0041] According to the present invention, a translucent resin sheet is provided, which comprises: a polarizing layer composed of a polarizer; and a protective layer, which is respectively arranged on both sides of the polarizing layer and mainly composed of a resin material. In the present invention, when the moisture content in the translucent resin sheet is set to A [%] and the total thickness of the two protective layers arranged on both sides of the polarizing layer is set to B [mm], when the translucent resin sheet is stored for 23 hours under the conditions of a temperature of 25° C. and a humidity of 50% Rh, the relationship A·B(1)[mm·%] of the product of the moisture content A and the total thickness B satisfies the relationship of 0.20≤A·B(1)≤0.70. Therefore, for example, as a translucent cover member that transmits the outgoing light emitted from the projection display, even if a translucent resin sheet is punched out corresponding to the shape of the outgoing window provided in the housing of the projection display, and then the translucent resin sheet is installed in a bent state corresponding to the outgoing window, the generation of cracks in the translucent resin sheet (translucent cover member) can be accurately suppressed or prevented. Furthermore, even if the projection display is exposed to high temperature such as a dashboard in summer, discoloration of the translucent resin sheet (translucent cover member) can be accurately suppressed or prevented. Therefore, the outgoing light transmitted through the translucent cover member can be reliably projected onto the screen in a color tone as designed. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 This is a side view showing an embodiment of a head-up display device for an automobile including the light-transmitting resin sheet of the present invention as a light-transmitting cover member.

[0043] Figure 2 It is magnified Figure 1 An enlarged cross-sectional view of the area [A] surrounded by a single-dot chain line.

[0044] Figure 3 yes Figure 2 An enlarged cross-sectional view of the light-transmitting resin sheet of the present invention used in the light-transmitting cover component. DETAILED DESCRIPTION

[0045] Hereinafter, the light-transmitting resin sheet, the projection display, and the moving object of the present invention will be described in detail based on the preferred embodiments shown in the drawings.

[0046] First, before describing the light-transmitting resin sheet and the moving body of the present invention, a head-up display device (projection display) for an automobile having the light-transmitting resin sheet of the present invention as a light-transmitting cover member will be described. That is, a head-up display device to which a projection display is applied will be described.

[0047] <Head-up display device>

[0048] Figure 1is a side view showing an embodiment of a head-up display device for an automobile having the light-transmitting resin sheet of the present invention as a light-transmitting cover member, Figure 2 It is magnified Figure 1 An enlarged cross-sectional view of the area [A] surrounded by a single-dot chain line in FIG. Figure 3 Is applied to Figure 2 The enlarged cross-sectional view of the light-transmitting resin sheet of the present invention of the light-transmitting cover component in FIG. Figure 1 to Figure 3 The upper side in the word is referred to as "upper" or "above", and the lower side is referred to as "lower" or "below". Figure 1 , Figure 2 The left side is called "front" or "front", and the right side is called "back" or "rear". Figure 3 In the figure, for easy understanding, the light-transmitting cover member is shown in a flat state, and the thickness direction is enlarged and schematically shown.

[0049] like Figure 1 As shown in FIG. 1 , a head-up display device 10 (Head-Up Display) is mounted and used in a car 100 . The head-up display device 10 is built in an upper portion of a dashboard 101 provided in the car 100 .

[0050] like Figure 2 As shown, the head-up display device 10 includes a display unit 11 , a reflective member 12 , and a housing 13 .

[0051] In the present embodiment, the display unit 11 is composed of a liquid crystal display, which emits a display image LS as outgoing light, and is configured to form a full-color display image LS by emitting red (R), green (G), and blue (B) color lights of each pixel constituting the display image LS from the display unit 11.

[0052] The reflecting member 12 is composed of, for example, a reflecting mirror, and can reflect the display image LS from the display unit 11. The display image LS reflected by the reflecting member 12 is projected onto the back surface 102a (inner surface) of the windshield 102, using the windshield 102 as a screen. And the projected light is recognized by the driver H as the display image LS (refer to Figure 1 , Figure 2 ).

[0053] like Figure 2 As shown, the housing 13 (housing) is box-shaped, and the display unit 11 or the reflective member 12, other parts constituting the head-up display device 10, etc. are housed therein. In addition, the housing 13 has a window portion 131 formed of an opening portion opened toward the windshield 102. The display image LS is emitted as outgoing light toward the outside of the housing 13, that is, the windshield 102, through the window portion 131.

[0054] Furthermore, in the window portion 131 of the container 13, a light-transmitting light-transmitting cover component 1 is formed with a recess in the central portion so that it is bent into a curved state in which the container 13 side becomes a convex state and the windshield 102 side becomes a concave state, and is arranged (installed) in a manner covering the window portion 131. Thus, the display image LS can be projected toward the windshield 102, and foreign matter such as dust and dirt can be prevented from intruding into the container 13 through the window portion 131. Therefore, the display image LS of the display unit 11 and the reflective component 12 can be prevented from being blurred or contaminated by the foreign matter. Furthermore, by being set to a curved state in which a recess is formed, the light-transmitting cover component 1 easily reflects sunlight, and can accurately suppress the sunlight from intruding into the container 13. Furthermore, for example, the light-transmitting cover component 1 can be prevented from protruding from the instrument panel 101, thereby preventing the light-transmitting cover component 1 from blocking the field of vision of the driver H.

[0055] The light-transmitting cover member 1 is composed of the light-transmitting resin sheet of the present invention, and includes: a polarizing layer 2 composed of a polarizer for generating polarized light of the light; and protective layers 3A and 3B, which are respectively provided on both sides of the polarizing layer 2 and are mainly composed of a resin material. When the moisture content (moisture content) in the light-transmitting resin sheet (light-transmitting cover member 1) is A[%] and the total thickness of the protective layers 3A and 3B is B[mm], the relationship A·B(1)[mm·%] of the product of the moisture content A and the total thickness B when the light-transmitting resin sheet (light-transmitting cover member 1) is stored for 23 hours under the conditions of a temperature of 25° C. and a humidity of 50%Rh satisfies the relationship of 0.20≤A·B(1)≤0.70.

[0056] In this way, the light-transmitting cover member 1 is formed of the light-transmitting resin sheet of the present invention, and the light-transmitting cover member 1 is punched out in accordance with the shape of the window 131 (exit window) provided in the housing 13 (housing) of the head-up display device 10 (projection display). Figure 2 As shown, even if a translucent resin sheet is installed in a bent state corresponding to the window portion 131, the generation of cracks in the translucent cover member 1 can be accurately suppressed or prevented. Moreover, since the instrument panel 101 is exposed to high temperatures in summer, the head-up display device 10 provided in the instrument panel 101 is also exposed to high temperatures. However, in this way, even if the head-up display device 10 (translucent cover member 1) is exposed to high temperatures, discoloration in the translucent cover member 1 can be accurately suppressed or prevented. Therefore, the display image LS (outgoing light) emitted from the display unit 11 can be reliably projected in a designed color tone on the back side 102a of the windshield 102 serving as a screen.

[0057] Hereinafter, each layer constituting the light-transmitting cover member 1, that is, the light-transmitting resin sheet of the present invention will be described.

[0058] like Figure 3 As shown, the light-transmitting cover member 1 can transmit light, and in the present embodiment, is a laminated plate including a polarizing layer 2, bonding layers 4A and 4B, and protective layers 3A and 3B. Each layer will be described below.

[0059] (Polarizing layer 2)

[0060] The polarizing layer 2 is an intermediate layer located at the center of the light-transmitting cover member 1 (light-transmitting resin sheet) in the thickness direction, and is a portion whose thickness is constant in the plane direction of the light-transmitting cover member 1 .

[0061] The polarizing layer 2 functions as a polarizer that extracts linearly polarized light having a polarization plane in a predetermined direction from the light that has passed through the light-transmitting cover member 1. Thus, the light that has passed through the light-transmitting cover member 1 is polarized.

[0062] The polarization degree of the polarizing layer 2 is preferably as close to 100% as possible, specifically, preferably 80.0% to 98.0%, more preferably 85.0% to 98.0%. This allows the polarizing layer 2 to reliably function as a polarizer.

[0063] Such a polarizing layer 2 is not particularly limited as long as it is a film having the above-mentioned functions. For example, it can be a film obtained by dyeing a polymer film composed of polyvinyl alcohol (PVA), partially formalized polyvinyl alcohol, polyethylene-vinyl alcohol, polyvinyl butyral, polycarbonate, a partially saponified product of ethylene-vinyl acetate copolymer, etc. with a dichroic substance such as iodine or a dichroic dye adsorbed thereon and then uniaxially stretched, a dehydrated product of polyvinyl alcohol, a dehydrochlorinated product of polyvinyl chloride, and the like, and a polyene-based oriented film.

[0064] Among these, the polarizing layer 2 is preferably a film obtained by dyeing a polymer film made of polyvinyl alcohol (PVA) by absorbing iodine or a dichroic dye and then uniaxially stretching it. Polyvinyl alcohol (PVA) is a material having excellent transparency, heat resistance, affinity with iodine or a dichroic dye as a dye, and orientation during stretching. Therefore, the polarizing layer 2 made of PVA as a main material has excellent heat resistance and excellent polarization ability.

[0065] Furthermore, by drying the polymer film after dyeing it with a dichroic dye or the like and by appropriately setting the drying conditions, the light-transmitting cover member 1 satisfying the relationship of 0.20≤A·B(1)≤0.70 can be obtained relatively easily.

[0066] Furthermore, the dichroic dye is not particularly limited, and examples thereof include Brilliant Blue 6B, solophenyl Blue FGLE220%, solophenyl Blue GL250%, KAYACELON Blue C-2R, Chlorazole Black BH, Direct Paper Blue STL, Solarus Ruby Red BLN, TOA Scarlet 4BS, Everpulp ORENGE 2G, Hamadai Paper Yellow R 125%, Direct Fast Orange S Kunk, BENZOPURPURIN, Diacotton Fast Orange WS, Direct Fast Orange S, AIZEN Primula Scarlet GSH, JAPANSOL Fast Black D conc., and the like. One or more of these may be used in combination.

[0067] In the present specification, the term "main material" refers to a constituent material contained in a layer containing the material in an amount of 50% by weight or more.

[0068] The thickness of the polarizing layer 2 is not particularly limited, for example, preferably 5 μm to 60 μm, more preferably 10 μm to 40 μm. If the thickness is less than the lower limit, the polarizing layer 2 may not fully function as a polarizer, and even if the thickness exceeds the upper limit, it is not expected that the function of the polarizer will be further improved.

[0069] The refractive index of the polarizing layer 2 is not particularly limited, but is preferably, for example, 1.50 or more and 1.60 or less, and more preferably 1.52 or more and 1.55 or less.

[0070] (Protective layers 3A, 3B)

[0071] And, if Figure 3 As shown, protective layer 3A is disposed on the upper surface side of polarizing layer 2 , and protective layer 3B is disposed on the lower surface side, thereby functioning as a water vapor barrier layer that protects polarizing layer 2 and prevents water vapor (moisture) from reaching polarizing layer 2 .

[0072] The protective layers 3A and 3B are not particularly limited, but are composed of a single layer made of a resin material such as a polyamide resin, a polycarbonate resin, or a cellulose resin such as triacetyl cellulose as a main material, and one or more of these materials can be used in combination. Among them, it is preferably composed of a polyamide resin or a polycarbonate resin as a main material, and more preferably composed of a polycarbonate resin as a main material.

[0073] The polycarbonate resin has high transparency (translucency) and mechanical strength such as rigidity, and thus can improve the transparency or impact resistance of the translucent cover member 1. Moreover, among the resin materials, the water vapor barrier property is excellent in the order of the polycarbonate resin, the polyamide resin, and the cellulose resin. It can be said that the polycarbonate resin is a resin material with particularly excellent water vapor barrier property, and thus the translucent cover member 1 satisfying the relationship of 0.20≤A·B(1)≤0.70 can be obtained relatively easily.

[0074] There is no particular limitation on the polyamide resin, and various resins can be used, for example, alicyclic polyamide, semi-aromatic polyamide, etc. Alicyclic polyamide is a material with excellent impact resistance. Therefore, the light-transmitting cover component 1 can exert excellent impact resistance. In addition, semi-aromatic polyamide is a material with a high elastic modulus. Therefore, the light-transmitting cover component 1 with excellent resistance to stress such as bending can be made.

[0075] In the present specification, the semi-aromatic polyamide refers to a polyamide in which one of dicarboxylic acid and diamine as monomers constituting the polyamide is an aromatic compound and the other is an aliphatic compound, and specifically, can be represented by the following formula (1B).

[0076]

[0077] (Wherein, R in formula (1B) 1 and R 2 In the above formula (A), one is a divalent aromatic substituent, the other is a divalent aliphatic substituent, and n is an integer greater than 2.)

[0078] In addition, the polyamide may be a copolymer (a random copolymer, a block copolymer, etc.) containing two or more monomers for at least one of the dicarboxylic acid and the diamine.

[0079] Furthermore, as R in the above formula (1B) 1 , R 2 The aromatic substituent in is preferably a group represented by the following formula (2B).

[0080]

[0081] (In formula (2B), l and m are each independently an integer of 0 to 2.)

[0082] This can more appropriately protect the polarizing layer 2 and further improve the processability of the light-transmitting cover member 1. Furthermore, when retardation is imparted to the protective layers 3A and 3B, the retardation caused by stretching the protective layers 3A and 3B can be more easily controlled.

[0083] In the above formula (1B), R1 , R 2 The aliphatic substituent in is preferably a group having 4 to 18 carbon atoms, more preferably a hydrocarbon group having 4 to 18 carbon atoms, and further preferably a saturated hydrocarbon group having 4 to 18 carbon atoms.

[0084] Thereby, the processability of the light-transmitting cover member 1 can be further improved.

[0085] Furthermore, the semi-aromatic polyamide is preferably a compound containing aromatic dicarboxylic acid and aliphatic diamine as constituent monomers. This can more appropriately protect the polarizing layer 2 and further improve the processability of the light-transmitting cover member 1. Furthermore, the retardation caused by stretching can be more easily controlled.

[0086] The alicyclic polyamide has an alicyclic chemical structure in its molecule, and may have the alicyclic chemical structure in the main chain structure or in the side chain structure.

[0087] Examples of the alicyclic polyamide include compounds in which at least one of dicarboxylic acid and diamine as monomers constituting the polyamide has an alicyclic chemical structure, and specifically, for example, the alicyclic polyamide can be represented by the following formula (3B).

[0088]

[0089] (Wherein, in formula (3B), R 3 , R 4 Each of them is independently a hydrogen atom or a hydrocarbon group having 4 or less carbon atoms, o is an integer of 2 or more and 14 or less, p is an integer of 0 or more and 6 or less, and n is an integer of 2 or more.

[0090] The polycarbonate resin is not particularly limited, and various resins can be used, but aromatic polycarbonate resins are preferred. Aromatic polycarbonate resins have an aromatic ring in the main chain, which can further improve the strength of the light-transmitting cover member 1 .

[0091] The aromatic polycarbonate resin is synthesized by, for example, an interfacial polycondensation reaction between bisphenol and phosgene, an ester exchange reaction between bisphenol and diphenyl carbonate, or the like.

[0092] Examples of the bisphenol include bisphenol A and bisphenol (modified bisphenol) that is a source of repeating units of the polycarbonate represented by the following formula (1A).

[0093]

[0094] (In formula (1A), X is an alkyl group, aromatic group or cyclic aliphatic group having 1 to 18 carbon atoms, Ra and Rb are each independently an alkyl group having 1 to 12 carbon atoms, m and n are each an integer of 0 to 4, and p is the number of repeating units.)

[0095] Specific examples of the bisphenols that are the origin of the repeating units of the polycarbonate represented by the formula (1A) include 4,4′-(pentane-2,2-diyl)diphenol, 4,4′-(pentane-3,3-diyl)diphenol, 4,4′-(butane-2,2-diyl)diphenol, 1,1′-(cyclohexanediyl)diphenol, 2-cyclohexyl-1,4-bis(4-hydroxyphenyl)benzene, 2,3-dicyclohexyl-1,4-bis(4-hydroxyphenyl)benzene, 1,1′-bis(4-hydroxy-3-methylphenyl)cyclohexane, and 2,2′-bis(4-hydroxy-3-methylphenyl)propane. One of these bisphenols may be used alone or two or more of them may be used in combination.

[0096] In particular, as the polycarbonate resin, it is preferable to use a bisphenol-type polycarbonate resin having a skeleton derived from bisphenol as a main component. By using this bisphenol-type polycarbonate resin, the light-transmitting cover member 1 can exhibit more excellent strength.

[0097] Furthermore, in addition to the resin material included as the main material, the protective layers 3A and 3B may also include other components. Such components are not particularly limited, and examples thereof include resin materials other than the main material or colorants such as dyes, fillers, orientation aids, stabilizers (thermal stabilizers, ultraviolet absorbers, antioxidants, etc.), plasticizers, colorants, flame retardants, antistatic agents, and viscosity modifiers.

[0098] At this time, the content of the resin material in the protective layers 3A and 3B is not particularly limited, but is preferably 75 parts by mass or more, and more preferably 85 parts by mass or more in 100 parts by mass of the protective layers 3A and 3B. By setting the content of the resin material within the above range, a light-transmitting cover component 1 having excellent strength can be obtained.

[0099] In addition, the constituent materials constituting the protective layers 3A and 3B may be the same or different.

[0100] When protective layers 3A and 3B are made to express retardation (phase difference; birefringence×thickness), the retardation of protective layer 3A is preferably different from the retardation of protective layer 3B, and the retardation of protective layer 3A is preferably lower than the retardation of protective layer 3B.

[0101] Thus, the protective layer 3B is easily deformed in the direction where the curvature decreases due to thermal contraction, but the protective layer 3A is not easily deformed due to thermal contraction. Figure 2As shown, by applying a translucent resin sheet to the translucent cover component 1 of the head-up display device 10, it can be used in a curved state, but at this time it is preferably set to a curved shape so that the protective layer 3B is located on the convex side of the curve and the protective layer 3A is located on the concave side of the curve. At this time, the thermal shrinkage rate of the protective layer 3B becomes relatively high, so it is relatively easy to deform by heat, but in the translucent cover component 1, the protective layer 3A plays a role in suppressing the thermal deformation of the protective layer 3B. Therefore, as a whole, the translucent cover component 1 can prevent excessive deformation caused by heat. As a result, it is possible to accurately suppress or prevent the thermal deformation of the translucent cover component 1 due to the instrument panel 101 being exposed to high temperatures in summer.

[0102] The delay of the protective layer 3A is preferably 0 nm or more and 500 nm or less, more preferably 50 nm or more and 350 nm or less. The delay of the protective layer 3B is preferably 2600 nm or more and 8000 nm or less, more preferably 3500 nm or more and 6500 nm or less. Thus, the delay of the protective layer 3A can be sufficiently reduced, and the delay of the protective layer 3B can be sufficiently increased. Thus, the effect obtained by making the delay of the protective layer 3A lower than the delay of the protective layer 3B can be more significantly exerted. In addition, the polarization performance of the light-transmitting cover component 1 can be sufficiently improved.

[0103] The difference in retardation between the protective layers 3A and 3B can be expressed by making the constituent materials or thicknesses contained in the layers different, and further making the stretching ratio and the like different.

[0104] The stretching ratio of the protective layer 3A is not particularly limited, but is preferably 0.95 or more and 1.1 or less, for example, as the magnitude of the retardation is set. The stretching ratio of the protective layer 3B is not particularly limited, but is preferably 1.5 or more and 3.5 or less, for example, as the magnitude of the retardation is set.

[0105] Furthermore, the stretching directions of the protective layer 3A, the protective layer 3B, and the polarizing layer 2 are preferably aligned with each other. This can further improve the polarization performance of the light-transmitting cover member 1.

[0106] The thickness of the protective layers 3A and 3B is, for example, preferably not less than 0.07 mm and not more than 0.80 mm, more preferably not less than 0.10 mm and not more than 0.50 mm, and further preferably not less than 0.12 mm and not more than 0.35 mm. By setting the thickness of the protective layers 3A and 3B within this range, the protective layers 3A and 3B can reliably perform the function of protecting the polarizing layer 2. Therefore, when the light-transmitting cover component 1 is installed in a manner covering the window portion 131 of the container 13 in a bent state in which the light-transmitting cover component 1 is bent, the light-transmitting cover component 1 can reliably function as a cover component covering the window portion 131. Furthermore, it is relatively easy to obtain a light-transmitting cover component 1 that satisfies the relationship of 0.20≤A·B(1)≤0.70.

[0107] Furthermore, the thicknesses of the protective layer 3A and the protective layer 3B may be the same or different as long as the light-transmitting cover member 1 satisfies the relationship of 0.20≤A·B(1)≤0.70.

[0108] The refractive index of the protective layers 3A and 3B is not particularly limited, but is preferably, for example, 1.45 or more and 1.66 or less, and preferably 1.48 or more and 1.60 or less.

[0109] In addition, in the present embodiment, the protective layers 3A and 3B are respectively composed of a single layer body whose main material is a resin material, but it is not limited to this. The protective layers 3A and 3B can also be respectively composed of a laminated body, which forms the following structure: for example, it has a first layer and a second layer whose main material is a resin material, and these first layer and second layer are bonded by a bonding layer.

[0110] (Joint layers 4A, 4B)

[0111] Furthermore, the polarizing layer 2 and the protective layer 3A are bonded together via a bonding layer 4A, and the polarizing layer 2 and the protective layer 3B are bonded together via a bonding layer 4B.

[0112] The bonding layer 4A and the bonding layer 4B are various adhesives or adhesives such as urethane adhesive, epoxy adhesive, acrylic adhesive, acrylic adhesive, etc. Thus, the layers can be reliably bonded to each other, and the light-transmitting cover member 1 that can withstand long-term use can be obtained.

[0113] The thickness of the bonding layers 4A and 4B is not particularly limited, and is preferably 0.005 mm or more and 0.04 mm or less, and more preferably 0.006 mm or more and 0.015 mm or less. If the thickness of the bonding layers 4A and 4B is less than the lower limit, it may sometimes lead to a decrease in the adhesive force, and if the thickness of the bonding layers 4A and 4B exceeds the upper limit, depending on the type of adhesive or adhesive, the curing / contraction of the bonding layers 4A and 4B may cause strain in the light-transmitting cover member 1. In addition, the thicknesses of the bonding layers 4A and 4B may be different, but are preferably the same.

[0114] The refractive index of the bonding layers 4A and 4B is not particularly limited, but is preferably, for example, 1.46 to 1.55, and more preferably 1.461 to 1.545.

[0115] The translucent cover member 1 (translucent resin sheet) having this configuration has the following problems as described in the above-mentioned background art.

[0116] That is, when the light-transmitting cover member 1 (light-transmitting resin sheet) corresponding to the shape of the window portion 131 (exit window) provided in the housing 13 (housing) of the head-up display device 10 (projection type display) is punched, or when the light-transmitting cover member 1 is bent to form a recessed portion in the center, there is a problem of cracks being generated in the light-transmitting cover member 1. In addition, the head-up display device 10 is provided in the instrument panel 101 of the automobile 100. In particular, since the instrument panel 101 is exposed to high temperatures in the summer, the light-transmitting cover member 1 is also heated, so that the light-transmitting cover member 1 changes color, and as a result, there is a problem that the display image LS (projected image) formed on the back surface 102a of the windshield 102 as a screen is projected onto the back surface 102a as a color tone different from the designed color tone.

[0117] In order to solve the problem, the inventors conducted in-depth research and found that these problems are related to the amount of water contained in the light-transmitting cover member 1, especially the polarizing layer 2. More specifically, it was found that if the amount of water contained in the light-transmitting cover member 1 (polarizing layer 2) is too little, the above cracks are generated in the light-transmitting cover member 1, and if the amount of water contained in the light-transmitting cover member 1 (polarizing layer 2) is too much, the above discoloration occurs in the light-transmitting cover member 1 when the light-transmitting cover member 1 is exposed to high temperature.

[0118] Furthermore, as a result of further research on the amount of moisture contained in the translucent cover member 1 (polarizing layer 2), the inventors found that the amount of moisture that exists in the translucent cover member 1 (particularly the polarizing layer 2) for a long time is closely related to the amount of moisture in the translucent cover member 1 as a whole and the thickness of the protective layers 3A and 3B. Specifically, it was found that when the water content in the translucent cover member 1 (translucent resin sheet) is set to A[%] and the total thickness of the protective layers 3A and 3B is set to B[mm], the translucent cover member 1 (translucent resin sheet) is stored at a temperature of 25°C and a humidity of 50%Rh for 23 hours. The product of the content A and the total thickness B satisfies the relationship of 0.20≤A·B(1)≤0.70, and the above-mentioned problem can be solved, thereby completing the present invention.

[0119] That is, by satisfying the relationship A·B(1)[mm·%] of 0.20≤A·B(1), when the translucent cover component 1 (translucent resin sheet) corresponding to the shape of the window portion 131 (exit window) of the container 13 (shell) of the head-up display device 10 (projection type display) is punched, or when the translucent cover component 1 is set to a bent state to form a recessed portion in the central portion, it is possible to accurately suppress or prevent the generation of cracks in the translucent cover component 1.

[0120] Furthermore, since the instrument panel 101 is exposed to high temperatures in summer, the head-up display device 10 provided in the instrument panel 101 is also exposed to high temperatures. However, since the relational expression A·B(1)[mm·%] satisfies the relation A·B(1)≤0.70, even if the head-up display device 10 (translucent cover member 1) is exposed to high temperatures, discoloration in the translucent cover member 1 can be accurately suppressed or prevented. Therefore, the display image LS (outgoing light) emitted from the display unit 11 can be reliably projected in a designed color tone on the back surface 102a of the windshield 102 serving as a screen.

[0121] In addition, it is speculated that when the water vapor barrier to the polarizing layer 2 is taken into consideration, not only the thickness of the protective layers 3A and 3B stacked on the polarizing layer 2 but also the thickness of the bonding layers 4A and 4B are included, which is related to the water vapor barrier to the polarizing layer 2. However, considering the relationship between the constituent materials contained in the above-mentioned protective layers 3A, 3B and the bonding layers 4A and 4B, and the thickness of the protective layers 3A, 3B and the bonding layers 4A and 4B, as the basis for parameter setting, it is considered appropriate to exclude the thickness of the bonding layers 4A and 4B, set the total thickness of the protective layers 3A and 3B to B [mm], and stipulate the size of the relationship A·B (1).

[0122] Furthermore, the water content A in the translucent cover member 1 is preferably, for example, 0.150% or more and 1.800% or less, more preferably 0.200% or more and 1.200% or less, and further preferably 0.400% or more and 1.000% or less. Thus, the translucent cover member 1 satisfying the relationship of 0.20≤A·B(1)≤0.70 can be obtained relatively easily.

[0123] The moisture content A (water vapor content) [%] in the light-transmitting cover member 1 can be measured using, for example, a moisture content measuring device (“AQUATRACK 3E” manufactured by ITS Japan Inc.).

[0124] Furthermore, the relationship A·B(1)[mm·%] only needs to satisfy the relationship 0.20≤A·B(1)≤0.70, but preferably satisfies the relationship 0.23≤A·B(1)≤0.52, and more preferably satisfies the relationship 0.23≤A·B(1)≤0.38. By setting A·B(1) within the above range, the above effect can be more significantly exerted. In addition, when it is desired to suppress the discoloration in the light-transmitting cover component 1 during high temperature exposure to a level that can be tolerated for practical use, while suppressing the cracks during the molding of the light-transmitting cover component 1 to a minimum, the relationship 0.42≤A·B(1)≤0.65 is preferred, and when further considering the balance between the two, the relationship 0.46≤A·B(1)≤0.60 is more preferred.

[0125] Moreover, the relationship A·B(2)[mm·%] of the product of the moisture content A and the total thickness B when the translucent cover component 1 is stored under different conditions such as storage at a temperature of 35°C and a humidity of 20%Rh for 22 hours preferably satisfies the relationship of 0.10≤A·B(2)≤0.42, and more preferably satisfies the relationship of 0.17≤A·B(2)≤0.30. By setting A·B(2) within the above range, the effect obtained by setting A·B(1) within the above range can be more significantly exerted. In addition, when it is desired to suppress the discoloration in the translucent cover component 1 when exposed to high temperature to a level that can be tolerated for practical use, and to suppress the cracks during the molding of the translucent cover component 1 to a minimum, the relationship of 0.32≤A·B(2)≤0.41 is preferred, and when further considering the balance between the two, the relationship of 0.33≤A·B(2)≤0.40 is more preferred.

[0126] Furthermore, by satisfying the relationship A·B(1)[mm·%], even if the light-transmitting cover component 1 is exposed to high temperature, its discoloration can be accurately suppressed or prevented. Specifically, after the light-transmitting cover component 1 (light-transmitting resin sheet) is stored at a temperature of 105°C and a humidity of 0%Rh for 1000 hours, the color change of the light-transmitting cover component 1 measured in accordance with ISO11664-4 preferably satisfies ΔE less than 13.5, more preferably satisfies ΔE less than 12.0, and further preferably satisfies ΔE less than 10.6. Thus, even if the light-transmitting cover component 1 is exposed to high temperature, its discoloration can be accurately suppressed or prevented.

[0127] The color change [ΔE] of the light-transmitting cover member 1 can be measured by the color value (L * a * b * ) to calculate.

[0128] As mentioned above, although the light-transmitting resin sheet, the projection type display, and the moving object of this invention were demonstrated, this invention is not limited to these.

[0129] For example, each part constituting the projection display and the moving body of the present invention can be replaced with any configuration that can exhibit the same function.

[0130] In addition, regarding the light-transmitting resin sheet of the present invention, in the above embodiment, a case where the polarizing layer 2 and the protective layers 3A and 3B stacked on the polarizing layer 2 are provided, and the polarizing layer 2 and the protective layers 3A and 3B are bonded via the bonding layers 4A and 4B is described, but it is not limited thereto. For example, the light-transmitting resin sheet may include an intermediate layer provided between the polarizing layer 2 and the bonding layers 4A and 4B, and between the protective layers 3A and 3B and the bonding layers 4A and 4B, or may include an outermost layer such as a hard coating layer stacked on at least one of the protective layers 3A and 3B. The intermediate layer may use a material different from that of the protective layer.

[0131] Furthermore, in the above-described embodiment, a case is described in which the projection display of the present invention is applied to the head-up display device 10 provided in the automobile 100 as a mobile body. However, the mobile body to which the head-up display device 10 is applied is not limited to the automobile 100, and examples thereof include ships, railway vehicles, airplanes, buses, motorcycles, bicycles, forklifts, work vehicles performing prescribed operations at construction sites, golf carts, and the like.

[0132] Furthermore, the light-transmitting resin sheet of the present invention is not limited to the use as the light-transmitting cover component of the above-mentioned head-up display device, but can also be applied to the lens of eyewear such as glasses and sunglasses. For example, the light-transmitting resin sheet of the present invention can be punched into the shape of a lens, and then the light-transmitting resin sheet in a curved state corresponding to the lens can be mounted on the surface of the lens for use.

[0133] [Example]

[0134] Hereinafter, the present invention will be described in more detail based on examples. However, the present invention is not limited to these examples.

[0135] 1. Preparation of various films

[0136] First, various films used for producing the light-transmitting resin sheets of each Example and each Comparative Example are shown below.

[0137] (PVA film)

[0138] As a PVA (polyvinyl alcohol) film, Kuraray Vinylon #7500 (manufactured by KURARAY CO., LTD.) was prepared.

[0139] (Protective film 1)

[0140] As the protective film 1 , a polycarbonate resin sheet (thickness: 0.325 mm) was prepared.

[0141] (Protective film 2)

[0142] As the protective film 2 , a polycarbonate resin sheet (thickness: 0.250 mm) was prepared.

[0143] (Protective film 3)

[0144] As the protective film 3 , a polycarbonate resin sheet (thickness: 0.125 mm) was prepared.

[0145] (Protective film 4A)

[0146] As the protective film 4A, a polyamide resin sheet (thickness: 0.400 mm) was prepared.

[0147] (Protective film 4B)

[0148] As the protective film 4B, a polyamide resin sheet (thickness: 0.200 mm) was prepared.

[0149] (Protective film 5)

[0150] As the protective film 5 , a triacetyl cellulose resin sheet (thickness: 0.080 mm) was prepared.

[0151] 2. Production of light-transmitting resin sheets

[0152] (Example 1)

[0153] <1> First, in a dyeing device equipped with a swelling tank, a dyeing tank, a cross-linking tank, and a dryer, the PVA film is stretched and dyed in an aqueous solution in which a dichroic dye is dissolved (4 g / L of Brilliant Blue 6B, 2 g / L of Phenoxyethanol, and 1 g / L of JAPANSOL Fast Black D conc.) at 40°C for 10 minutes, cross-linked with boric acid, and then dried at 80°C and 0% Rh for 5 minutes, thereby forming a polarizing layer 2.

[0154] <2> Next, the protective film 1 as protective layers 3A and 3B was pressure-bonded to both surfaces of the obtained polarizing layer 2 via a one-component moisture-curable polyurethane adhesive, thereby producing a light-transmitting resin sheet of Example 1 having a total thickness of 0.7 mm.

[0155] (Example 2 to Example 5, Example 8, Example 9)

[0156] In the step <2>, except that the combination of the protective films pressed as the protective layers 3A and 3B had the layer configuration shown in Table 1, the same method as in the example 1 was carried out to obtain light-transmitting resin sheets of examples 2 to 5, 8, and 9.

[0157] (Example 6, Example 7, Comparative Example 1, Comparative Example 2)

[0158] In the step <1>, except that the conditions for obtaining the polarizing layer 2 by drying were set to the conditions shown in Table 1, the same method as in Example 1 was carried out to obtain light-transmitting resin sheets of Example 6, Example 7, Comparative Example 1, and Comparative Example 2.

[0159] (Example 10)

[0160] A light-transmitting resin sheet of Example 10 was obtained in the same manner as in Example 1, except that the drying of the polarizing layer 2 in the step <1> was omitted.

[0161] 3. Evaluation

[0162] The light-transmitting resin sheets of each Example and each Comparative Example were evaluated by the following methods.

[0163] Calculation of the relational expression A·B(1)

[0164] First, the light-transmitting resin sheets of each example and each comparative example were stored under the conditions of a temperature of 25° C. and a humidity of 50% Rh for 23 hours.

[0165] Then, the water content (water content) A in the light-transmitting resin sheet after being stored under the above conditions was measured using a water content measuring device (“AQUATRACK 3E” manufactured by ITS Japan Inc.).

[0166] Then, the magnitude of A·B(1) was determined from the obtained water content A and the total thickness B of the protective layers 3A and 3B included in the light-transmitting resin sheet.

[0167] Calculation of the relational expression A·B(2)

[0168] First, the light-transmitting resin sheets of each example and each comparative example were stored under the conditions of a temperature of 35° C. and a humidity of 20% Rh for 22 hours.

[0169] Then, the water content (water content) A in the light-transmitting resin sheet after being stored under the above conditions was measured using a water content measuring device (“AQUATRACK 3E” manufactured by ITS Japan Inc.).

[0170] Then, the magnitude of A·B(2) was determined from the obtained water content A and the total thickness B of the protective layers 3A and 3B included in the light-transmitting resin sheet.

[0171] <C> Evaluation of bending test

[0172] First, the light-transmitting resin sheets of each embodiment and each comparative example were punched out to produce 5 cm square test pieces, and then these test pieces were heated to 140°C and subjected to heat bending, thereby forming a curved state with a curvature radius of 80 mm. In addition, 20 test pieces set to the curved state were formed for each of the light-transmitting resin sheets of each embodiment and each comparative example, and the appearance of each test piece was observed by naked eyes to confirm whether cracks were generated in the test piece.

[0173] <D> Evaluation of heat resistance test

[0174] The color values ​​(L * a * b * ) was used to calculate the color change (ΔE) after storage for 1000 hours under the conditions of temperature 105°C and humidity 0% Rh.

[0175] The evaluation results of the light-transmitting resin sheets of each Example and each Comparative Example obtained as described above are shown in Table 1 below.

[0176]

[0177] As shown in Table 1, in the light-transmitting resin sheet in each example, the relational expression A·B(1)[mm·%] satisfies the relation of 0.20≤A·B(1)≤0.70. As a result, the following results are shown: even if the light-transmitting resin sheet is formed into a curved shape, the generation of cracks in the light-transmitting resin sheet can be accurately suppressed or prevented, and even if the light-transmitting resin sheet is exposed to high temperature, the generation of discoloration in the light-transmitting resin sheet can be accurately suppressed or prevented.

[0178] In contrast, in the light-transmitting resin sheet of Comparative Example 1, the relational expression A·B(1)[mm·%] indicates less than 0.20, and does not satisfy the relation of 0.20≤A·B(1)≤0.70. As a result, it is shown that if the light-transmitting resin sheet is formed into a curved shape, cracks are generated in the light-transmitting resin sheet. Furthermore, in the light-transmitting resin sheet of Comparative Example 2, the relational expression A·B(1)[mm·%] indicates more than 0.70, and does not satisfy the relation of 0.20≤A·B(1)≤0.70. As a result, it is shown that if the light-transmitting resin sheet is exposed to high temperature, discoloration is observed in the light-transmitting resin sheet.

[0179] Industrial Applicability

[0180] According to the present invention, a translucent resin sheet is provided, which comprises: a polarizing layer composed of a polarizer; and a protective layer, which is respectively arranged on both sides of the polarizing layer and mainly composed of a resin material. In the present invention, when the moisture content in the translucent resin sheet is set to A [%] and the total thickness of the two protective layers arranged on both sides of the polarizing layer is set to B [mm], when the translucent resin sheet is stored for 23 hours under the conditions of a temperature of 25° C. and a humidity of 50% Rh, the relationship A·B(1)[mm·%] of the product of the moisture content A and the total thickness B satisfies the relationship of 0.20≤A·B(1)≤0.70. Therefore, for example, as a translucent cover component that transmits the outgoing light emitted from the projection display, even if a translucent resin sheet is punched out corresponding to the shape of the outgoing window provided in the housing of the projection display, and then the translucent resin sheet is installed in a bent state corresponding to the outgoing window, the generation of cracks in the translucent resin sheet (translucent cover component) can be accurately suppressed or prevented. Moreover, even if the projection display is exposed to high temperature like a dashboard in summer, discoloration of the translucent resin sheet (translucent cover component) can be accurately suppressed or prevented. Therefore, the outgoing light transmitted through the translucent cover component can be reliably projected onto the screen in a color tone as designed. Therefore, the present invention has industrial applicability.

[0181] Description of Reference Numerals

[0182] 1- light-transmitting cover component,

[0183] 2- Polarization layer,

[0184] 3A-protective layer,

[0185] 3B-Protective layer,

[0186] 4A-Joint layer,

[0187] 4B-bonding layer,

[0188] 10- Head-Up Display,

[0189] 11- Display unit,

[0190] 12- reflective component,

[0191] 13- container,

[0192] 131-Window,

[0193] 100-car,

[0194] 101-Dashboard,

[0195] 102- Windshield,

[0196] 102a - back side (inner side),

[0197] H - Driver,

[0198] LS - Displays the image.

Claims

1. A light-transmitting resin sheet comprising: a polarizing layer composed of a polarizer that generates polarized light; and The protective layers are respectively arranged on the two sides of the polarizing layer and are mainly composed of a resin material. The light-transmitting resin sheet is characterized in that When the water content in the light-transmitting resin sheet is represented by A [%] and the total thickness of the two protective layers provided on both sides of the polarizing layer is represented by B [mm], When the translucent resin sheet is stored at a temperature of 25° C. and a humidity of 50% Rh for 23 hours, the relationship A·B(1) [mm·%] of the product of the content A and the total thickness B satisfies the relationship of 0.20≤A·B(1)≤0.

70.

2. The light-transmitting resin sheet according to claim 1, wherein When the translucent resin sheet is stored at a temperature of 35° C. and a humidity of 20% Rh for 22 hours, the relationship A·B(2) [mm·%] of the product of the content A and the total thickness B satisfies the relationship of 0.10≤A·B(2)≤0.

42.

3. The light-transmitting resin sheet according to claim 2, wherein After the light-transmitting resin sheet is stored under conditions of a temperature of 105° C. and a humidity of 0% Rh for 1000 hours, a color change of the light-transmitting resin sheet measured in accordance with ISO11664-4 satisfies ΔE of less than 13.

5.

4. The light-transmitting resin sheet according to claim 1 or 3, wherein The protective layer is a single layer mainly composed of the resin material. The resin material is a polycarbonate resin.

5. The light-transmitting resin sheet according to claim 1, wherein The polarizing layer has a thickness of 5 μm or more and 60 μm or less.

6. The light-transmitting resin sheet according to claim 1, wherein The protective layer has a thickness of 0.07 mm or more and 0.80 mm or less.

7. The light-transmitting resin sheet according to claim 1, wherein The protective layer and the polarizing layer are bonded via a bonding layer.

8. The light-transmitting resin sheet according to claim 7, wherein The thickness of the bonding layer is greater than or equal to 0.005 mm and less than or equal to 0.04 mm.

9. The light-transmitting resin sheet according to claim 1, wherein The light-transmitting resin sheet is used as the light-transmitting cover member that transmits light emitted from a projection display.

10. A projection display, characterized in that: The light-transmitting resin sheet according to claim 9 is provided as a light-transmitting cover member capable of transmitting light.

11. A mobile object, characterized in that: A projection display according to claim 10 is provided.

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