TW202144858A - Head-up display - Google Patents

Abstract

This head-up display is provided with: a polarizing member (18) including a first supporting plate (30) and a second supporting plate (38) that are provided on a polarizing plate (34); a display (12) that outputs an image including a linear polarization component; and a housing (10) that houses the display (12). The polarizing member (18) is used as a light transmissive cover through which the image is transmitted to the outside of the housing (10). The angle formed by the transmission axis of the polarizing plate (34) and the polarizing direction of the image outputted from the display (12) is set in a relationship except parallel and orthogonal angles, and the image transmitted through the polarizing member (18) projects, as a projection image, a virtual image containing polarized light in a horizontal direction and a vertical direction.

Description

head-up display

The present disclosure relates to a head-up display.

A head-up display device (hereinafter referred to as a HUD device) can display an image on a display such as a monitor, and the image is mirror-reflected and projected on a glass or the like as a virtual image. In particular, various kinds of information can be displayed gradually due to the higher performance of the display device. These HUD devices are generally used to display information and the like in a manner overlapping with the user's normal field of vision. For example, in the case of an automobile, vehicle speed information and the like are displayed on the front glass, the combiner, and the like.

HUD devices for vehicles are generally provided with a light-transmitting cover, which is installed so as to prevent dust or dust from entering through a projection port for transmitting an image from the device main body. Projected onto a projection portion such as glass. From the viewpoint of strength and prevention of scattering at the time of collision, as a light-transmitting cover (hereinafter referred to as a light-transmitting cover), a resin material containing polycarbonate is generally used.

In addition, in the HUD device, there is a problem in that the display portion inside the device is degraded by the load due to heat and light due to the incidence of external light (sunlight), thereby degrading the development quality. As a measure against this, various techniques for shielding incident sunlight and the like have been proposed. Among them, in order to shield sunlight incident from the outside without lowering the luminance of the light emitted from the display unit, it has been proposed to provide a light-transmitting cover with polarization properties (Patent Document 1). In particular, by using a cover with a gray absorbing polarizing layer, not only can the penetration of sunlight be reduced, but also the internal structure of the HUD device can be hidden, and the color tone of the instrument panel can be matched.

Further, in recent HUD devices, not only the projected display information is refined, but also the design of projecting information on a wider area of the front glass is progressing. With this situation, the concave mirror (also called concave mirror) in the device is progressing. The width of the projected light becomes larger, so the area of the light-transmitting cover through which it transmits also needs to be larger.

However, when a liquid crystal display device (LCD) is used for a display portion, etc., in a display body that emits linearly polarized light from the display portion, the emitted light is generally polarized light in the horizontal direction (hereinafter referred to as S-polarized light). On the other hand, when the driver of the vehicle wears polarized sunglasses, in general, the absorption axis of the polarized sunglasses is in the horizontal direction, so there is a problem that the polarized light reaching the horizontal direction of the driver is blocked by the polarized sun. The glasses block, so that the displayed image (virtual image) becomes difficult to see. Therefore, as a method of ensuring visibility when wearing polarized sunglasses, a method has been proposed in which a light-shielding polarizer, a retardation plate with a wavelength of λ/4 or λ/2, or a light-shielding polarizer having a wavelength of 3000 nm or more has been proposed. Optical members such as films with a high retardation value are used in the optical path or light-transmitting cover of the HUD device (Patent Documents 2 and 3). [Prior Art Literature] (patent literature)

Patent Document 1: Japanese Patent Laid-Open No. 2010-113197 Patent Document 2: Japanese Patent Laid-Open No. 2014-115408 Patent Document 3: Japanese Patent Laid-Open No. 2019-079040

[Problems to be Solved by Invention]

For the above-mentioned countermeasures, when new retardation plates such as λ/4 wavelength and λ/2 wavelength are added in the HUD device or on the light-transmitting cover member, the production cost increases due to the increase of materials used. Furthermore, there are problems such as reduction in the amount of light (brightness) from the developing device, coloration of the displayed image due to the influence of wavelength dispersion of the retardation plate, and limitation of the installation place of the optical member. In addition, when the optical member is arranged in the optical path, the concave mirror becomes larger in order to project an image showing information on a wide area, so that the concave mirror has a stronger light-collecting effect on incident sunlight. Therefore, the amount of light absorbed by the optical member also increases, and the deterioration of the optical member may be accelerated.

In addition, when the above-mentioned film having a high retardation value is used, for example, it needs to be attached to the output side of the light-transmitting cover. At this time, since the polarized light emitted from the display unit is arranged in a predetermined optical axis relationship, for example, roll-to-roll processing with the polarizing layer may not be possible, and the production efficiency of the cover member may decrease. In addition, since the symmetry in the thickness direction of the light-transmitting cover is lost, the cover member may be deformed by warping or the like when exposed to a thermal load due to sunlight for a long period of time. Furthermore, as a result, the displayed image may be distorted or may fall off the device. In particular, when the area of the light-transmitting case cover becomes larger, this influence becomes remarkable.

Therefore, an object of the present disclosure is to provide a head-up display that can reduce the incidence of sunlight into a HUD device, and can even wear polarized sunglasses without using a retardation plate in the HUD device and a light-transmitting cover. The display image can also be viewed. [Technical means to solve the problem]

In the HUD device, it was found that by arranging the light-transmitting cover in such a way that the transmission axis of the light-transmitting cover with the polarizing layer does not coincide with the direction of the polarized light emitted by the display unit, even when wearing polarized sunglasses, it is possible to improve the performance of the light-transmitting cover. Display image brightness.

That is, an aspect of the present disclosure is a head-up display comprising: a polarizing member including a polarizing layer and a support plate disposed on at least one side of the polarizing layer; a developing device that outputs an image including a linearly polarized component; and, a frame body, which houses the developing device; the polarizing member is used as a light-transmitting case cover, the light-transmitting case cover transmits the image to the outside of the frame body, and the transmission axis of the polarizing layer is related to the developing image. The angle formed by the polarization direction of the image output by the device is set to exclude the parallel and vertical angles, and the image transmitted through the polarization member is a virtual image including horizontal and vertical polarizations projected as a projected image.

Here, the transmission axis of the polarizing layer may be set to be 5 to 45 degrees with respect to the polarization direction of the image output by the developing device.

In addition, the retardation value (Re) at a wavelength of 550 nm of the polarizing film of the polarizing layer with respect to the polarized light of the image output by the developing device can be set to n×550±150 nm (n is 0, 1, 2･･･ integer). [Effect of invention]

According to the present disclosure, it is possible to provide a head-up display capable of reducing the incidence of sunlight into a HUD device, and without using these retardation plates in the HUD device and the light-transmitting cover, even when wearing polarized sunglasses Display images can also be viewed.

As shown in FIGS. 1 and 2 , the HUD device 100 in the embodiment of the present disclosure includes a housing 10 , a display unit 12 , a flat mirror 14 , a concave mirror 16 , a polarizing member (polarizing case cover) 18 , and a projection unit 20 and constitute.

The housing 10 accommodates constituent elements such as the display unit 12 , the flat mirror 14 , and the concave mirror 16 constituting the HUD device 100 . The frame body 10 is made of materials with mechanical strength such as plastic and metal.

The display 12 is a device that outputs the image projected by the HUD device 100 . The display unit 12 is constituted by a liquid crystal display (LCD) or the like. The image light emitted by the developing device 12 is linearly polarized. Considering the influence of Brewster's angle (polarization angle) incident on the projection unit 20, the image light emitted by the developing device 12 is generally designed with an S-polarized component so that the luminance of the virtual image in the projection unit 20 becomes the maximum.

The flat mirror 14 is arranged to reflect the image light emitted by the imager 12 towards the concave mirror 16 . The concave mirror 16 is provided to reflect the image light arriving from the flat mirror 14 toward the projection unit 20 . The concave mirror 16 can magnify the image light at a desired magnification and project it to the projection unit 20 .

The polarizing member (polarizing case cover) 18 is a translucent plate-shaped member, and is attached to an opening provided in the frame body 10 . The polarizing member 18 is provided as a light-transmitting cover in such a manner that the image light reflected by the concave mirror 16 is transmitted to the outside of the housing 10 , and dust or dust does not enter the interior of the housing 10 . The configuration of the polarizing member 18 will be described later.

The projection unit 20 receives the image light that has reached the concave mirror 16 and projects the virtual image as a projected image. The projection unit 20 can be used as a windshield of a vehicle. In addition, as shown in FIG. 2 , in order to ensure the normal vision of the user, the projection unit 20 can also be formed as a combiner including a half mirror or a holographic element. Moreover, the projection part 20 may be comprised so that the attachment angle and attachment position with respect to the housing|casing 10 can be changed. Thereby, the position and the angle of the projection unit 20 can be adjusted so that the projected image can be easily seen in accordance with the line of sight of the user.

The polarizing member 18 includes a polarizing plate 34 having a polarizer. FIG. 3 shows a cross-sectional structure of an example of the polarizing member 18 . In the present embodiment, the polarizing member 18 is configured by laminating the first support plate 30 , the adhesive layer 32 , the polarizer 34 , the adhesive layer 36 , and the second support plate 38 . Moreover, as shown in FIG. 4, the polarizing member 18 can be set as the structure in which the 1st support plate 30, the adhesive layer 32, and the polarizing plate 34 are laminated|stacked.

[polarizing plate] The polarizing plate 34 is a layer including a polarizer capable of transmitting only light polarized in a specific direction. The polarizing plate 34 can be arbitrarily selected, and can be an absorption-type polarizing plate. For example, a polarizing plate obtained by dyeing a polyvinyl alcohol (PVA) film with an iodine-based or dye-based dichroic dye, and a solution containing a dichroic dye such as a dye-based material can be applied by coating or the like. A coated polarizer that is clothed on a substrate and oriented.

As an example of the above-mentioned PVA film, VF-PS#7500 (product name) manufactured by KURARAY Corporation and the like can be applied. The PVA film is, for example, dyed with a solution containing a dichroic dye, then stretched to a thickness of 75 μm before stretching, and then uniaxially stretched to a thickness of about 30 μm. Thereby, a PVA thin film is formed as the polarizing plate 34 . This aspect is also commonly referred to as a polarizing film (polarizer film).

The polarizing plate 34 may be formed of a dye-based material. The dye-based material may be a dichroic dye. When a dichroic dye such as an azo-based compound, an anthraquinone-based compound, a tetrazine-based compound, or a salt thereof is used as the dichroic dye, the durability of the optical properties under high temperature conditions or under high temperature and high humidity conditions is excellent, and it is not only easy to It is preferable to adjust the hue so that there is no yellowishness due to the waveform characteristics of the iodine-based polarizing plate. Since the degree of polarization is high and durability is excellent, it is more preferably an azo compound.

(式中，R₁ 表示氫原子、低級烷基、低級烷氧基、羥基、磺酸基、或羧基，R₂ ～R₅ 各自獨立地表示氫原子、低級烷基、低級烷氧基、或乙醯胺基，X是可具有取代基的苯甲醯胺基、可具有取代基的苯胺基、可具有取代基的苯基偶氮基、或可具有取代基的萘并三唑基，m表示1或2，n表示0或1。) (2)日本再公表專利WO2007/145210(A1)所揭示的由化學式(2)表示的偶氮化合物或其鹽。

(式中，A表示具有取代基的苯基或具有1～3個磺酸基的萘基，X表示-N=N-或-NHCO-。R₁ ～R₄ 各自獨立地表示氫原子、低級烷基或低級烷氧基，m＝1～3，n＝0或1。) (3)日本再公表專利WO2006/057214(A1)所揭示的由化學式(3)表示的三偶氮染料。

(式中，R₁ 表示磺酸基、羧基或低級烷氧基，R₂ 表示磺酸基、羧基、低級烷基或低級烷氧基。其中，R₁ 、R₂ 皆為磺酸基的情況除外。R₃ ～R₆ 各自獨立地表示氫原子、低級烷基或低級烷氧基，R₇ 、R₈ 各自獨立地表示氫原子、胺基、羥基、磺酸基或羧基。) (4)日本特開2004-251963號公報所揭示的由化學式(4)表示的含金屬雙偶氮化合物或其鹽。

(式中，M表示選自銅、鎳、鋅及鉄中的過渡金屬；A¹ 表示可經取代的苯基或可經取代的萘基；B¹ 表示可經取代的1-萘酚或2-萘酚殘基，該萘酚的羥基位於偶氮基的鄰接位，與由M表示的過渡金屬錯合；R¹ 和R² 各自獨立地表示氫、低級烷基、低級烷氧基、羧基、磺基、胺磺醯基、N-烷基胺磺醯基、胺基、醯胺基、硝基或鹵素。) (5)由化學式(5)表示的三偶氮化合物。

(式中，A² 和B² 各自獨立地表示可經取代的苯基或可經取代的萘基；R³ 和R⁴ 各自獨立地表示氫、低級烷基、低級烷氧基、羧基、磺基、胺磺醯基、N-烷基胺磺醯基、胺基、醯胺基、硝基或鹵素；m表示0或1。) (6)日本特開平3-12606號公報所揭示的由化學式(6)表示的水溶性化合物或其銅錯鹽化合物。

(式中，A表示經甲基取代的苯基或萘基，R表示胺基、甲胺基、乙胺基或苯胺基。) (7)日本特開平2-61988號公報所揭示的由化學式(7)表示的水溶性雙偶氮化合物或其銅錯鹽化合物。

(8)其他，可列舉例如：C.I.Direct Yellow 12、C.I.Direct Yellow 28、C.I.Direct Yellow 44、C.I.Direct Yellow 142、C.I.Direct Orange 26、C.I.Direct Orange 39、C.I.Direct Orange 71、C.I.Direct Orange 107、C.I.Direct red 2、C.I.Direct red 31、C.I.Direct red 79、C.I.Direct red 81、C.I.Direct red 117、C.I.Direct red 247、C.I.Direct Green 80、C.I.Direct Green 59、C.I.Direct Blue 71、C.I.Direct Blue 78、C.I.Direct Blue 168、C.I.Direct Blue 202、C.I.Direct Violet 9、C.I.Direct Violet 51、C.I.Direct Brown 106、C.I.Direct Brown 223等。再者，較佳是：藉由以彌補在可見光區域的各波長時的偏光特性的方式摻合2種或3種以上的這些染料，並對PVA染色，從而製成呈中性灰的色相。As the azo compound dye, the following dyes can be exemplified. (1) The azo compound represented by chemical formula (1) or a salt thereof disclosed in Japanese Republished Patent WO2009/057676(A1).

(wherein, R ₁ represents a hydrogen atom, a lower alkyl group, a lower alkoxy group, a hydroxyl group, a sulfonic acid group, or a carboxyl group, and R ₂ to R ₅ each independently represent a hydrogen atom, a lower alkyl group, a lower alkoxy group, or Acetamide group, X is an optionally substituted benzylamino group, an optionally substituted aniline group, an optionally substituted phenylazo group, or an optionally substituted naphthotriazolyl group, m Represents 1 or 2, and n represents 0 or 1.) (2) The azo compound represented by the chemical formula (2) or a salt thereof disclosed in Japanese Republished Patent WO2007/145210(A1).

(In the formula, A represents a substituted phenyl group or a naphthyl group having 1 to 3 sulfonic acid groups, and X represents -N=N- or -NHCO-. R ₁ to R ₄ each independently represent a hydrogen atom, a lower Alkyl group or lower alkoxy group, m=1-3, n=0 or 1.) (3) Trisazo dye represented by chemical formula (3) disclosed in Japanese Republished Patent WO2006/057214(A1).

(In the formula, R ₁ represents a sulfonic acid group, a carboxyl group or a lower alkoxy group, and R ₂ represents a sulfonic acid group, a carboxyl group, a lower alkyl group or a lower alkoxy group. The case where both R ₁ and R ₂ are sulfonic acid groups Except that R ₃ to R ₆ each independently represent a hydrogen atom, a lower alkyl group or a lower alkoxy group, and R ₇ and R ₈ each independently represent a hydrogen atom, an amino group, a hydroxyl group, a sulfonic acid group or a carboxyl group.) (4) The metal-containing bisazo compound represented by the chemical formula (4) or a salt thereof disclosed in Japanese Patent Laid-Open No. 2004-251963.

(in the formula, M represents a transition metal selected from copper, nickel, zinc and iron; A ¹ represents a substituted phenyl group or a substituted naphthyl group; B ¹ represents a substituted 1-naphthol or 2 - a naphthol residue, the hydroxyl group of the naphthol is located at the vicinal position of the azo group, complexed with the transition metal represented by M; R ¹ and R ² each independently represent hydrogen, lower alkyl, lower alkoxy, carboxyl , sulfo group, sulfamoyl group, N-alkyl sulfamoyl group, amino group, amide group, nitro group or halogen.) (5) The trisazo compound represented by the chemical formula (5).

(In the formula, A ² and B ² each independently represent a substituted phenyl group or a substituted naphthyl group; R ³ and R ⁴ each independently represent hydrogen, lower alkyl, lower alkoxy, carboxyl, sulfone group, sulfamoyl group, N-alkyl sulfamoyl group, amine group, amide group, nitro group or halogen; m represents 0 or 1.) (6) As disclosed in Japanese Patent Laid-Open No. 3-12606 The water-soluble compound represented by the chemical formula (6) or a copper zirconium salt compound thereof.

(In the formula, A represents a methyl-substituted phenyl group or naphthyl group, and R represents an amino group, a methylamino group, an ethylamino group, or an aniline group.) (7) The chemical formula disclosed in Japanese Patent Laid-Open No. 2-61988 The water-soluble disazo compound represented by (7) or its copper zirconium salt compound.

(8) Others, for example: CIDirect Yellow 12, CIDirect Yellow 28, CIDirect Yellow 44, CIDirect Yellow 142, CIDirect Orange 26, CIDirect Orange 39, CIDirect Orange 71, CIDirect Orange 107, CIDirect red 2, CIDirect red 31, CIDirect red 79, CIDirect red 81, CIDirect red 117, CIDirect red 247, CIDirect Green 80, CIDirect Green 59, CIDirect Blue 71, CIDirect Blue 78, CIDirect Blue 168, CIDirect Blue 202, CIDirect Violet 9, CIDirect Violet 51, CIDirect Brown 106 , CIDirect Brown 223, etc. Furthermore, it is preferable to prepare a neutral gray hue by blending two or three or more of these dyes so as to compensate for the polarization characteristics at each wavelength in the visible light region, and then dyeing PVA.

Moreover, as a commercially available dye, Kayafect Violet P Liquid (made by Nippon Kayaku Co., Ltd.), Kayafect Yellow Y, Kayafect ORange G, Kayafect Blue KW, Kayafect Blue Liquid 400, etc. are mentioned.

Moreover, the polarizing plate 34 can be set as the structure which bonded the polarizing film obtained by the said manufacturing method to a base material. The base material is a member that serves as a protective layer of the polarizing plate 34 . The base material can be arbitrarily selected, and for example, a triacetate cellulose (TAC) film, an acrylic film, a cyclic olefin-based film, or the like can be used. The thickness of the base material is not limited to this, but can be 20 μm or more and 200 μm or less. In order to obtain a polarizer with less optical change with respect to heat or humidity and suppressed shrinkage or warpage, it is preferable to provide the same base material on both sides of the polarizing film. In the present disclosure, the polarizing layer includes any aspect of a polarizing layer having a substrate on the polarizing plate 34 and a polarizing layer having no substrate.

[adhesive layer] The adhesive layer 32 is a layer for bonding the polarizing plate 34 and the first support plate 30 . In addition, the adhesive layer 36 is a layer for bonding the polarizing plate 34 and the second support plate 38 together. The adhesive or adhesive used for the adhesive layer 32 and the adhesive layer 36 is not particularly limited, and may be an adhesive/adhesive containing the following materials capable of imparting heat insulation or flame retardancy. In addition, the adhesive layer 32 and the adhesive layer 36 can be made of materials that can absorb (buffer) when a force such as thermal stress acts between the polarizing plate 34 and the first support plate 30 or the second support plate 38 The force of the material. The adhesive/binder used for the adhesive layer is not particularly limited, and examples thereof include adhesive components obtained by blending polyvinyl alcohol-based resins, urethane resins, and the like with isocyanate-based compounds, epoxy compounds, and the like; or, Adhesive components such as acrylic resin and polyester resin. The film thicknesses of the adhesive layer 32 and the adhesive layer 36 can generally be appropriately designed in the range of 0.1 μm or more and 50 μm or less in consideration of the adhesion between layers and the appearance characteristics due to the undulation (optical distortion) of the cover member. choose.

The method of forming the adhesive layer 32 and the adhesive layer 36 is not particularly limited. For example, when it is formed as an adhesive, the following method can be used: diluting the adhesive layer 32 and the adhesive layer 36 with a solvent such as toluene or methyl ethyl ketone (MEK). An adhesive composition obtained from solid components such as an ester resin and a hardener is applied to an object to be adhered, and after further lamination, the applied adhesive composition is cured. In addition, a droplet method or the like can also be applied.

[support plate] The first support plate 30 and the second support plate 38 are members for mechanically supporting the polarizing member 18 . That is, the first support plate 30 is bonded to the surface of the polarizing plate 34 via the adhesive layer 32 . In addition, the second support plate 38 is bonded to the back surface of the polarizing plate 34 with the adhesive layer 36 interposed therebetween.

The first support plate 30 and the second support plate 38 may include flame-retardant plastic plates. That is, by constituting the first support plate 30 and the second support plate 38 with flame-retardant plastic sheets, it is possible to realize the HUD device 100 that meets the requirements of the polarizing member 18 for which flame-retardant properties are required. Specifications for installation in automobiles, etc.

For example, the first support plate 30 and the second support plate 38 may be a polycarbonate (PC) board, an acrylic resin board, a cellulose board, a nylon board, or the like. The acrylic resin plate can be, for example, polymethyl methacrylate (PMMA) or the like. Moreover, the 1st support plate 30 and the 2nd support plate 38 may be made into the material which carried out incombustibility processing to a combustible material. In consideration of the mechanical strength of the polarizing member 18 , the thickness of the first support plate 30 and the second support plate 38 may be 50 μm or more, respectively.

In addition, the first support plate 30 and the second support plate 38 can be made of the following materials: polycarbonate (PC) mixed with at least one of metal oxides, halogen compounds, and phosphorus compounds, or coated with metal oxides, halogen compounds, A material obtained by making at least one kind of phosphorus compound flame retardant. Bromine in halogen compounds can be used in consideration of price, coloring, characteristics of polycarbonate (PC) and impact on the environment. When at least one of a metal, a halogen compound, and a phosphorus compound is mixed with polycarbonate (PC), the selected raw materials may be kneaded into polycarbonate (PC).

In addition, the first support plate 30 and the second support plate 38 may have a structure in which a plurality of layers are laminated instead of a single layer. For example, it is possible to have a structure in which a polycarbonate (PC) board is used as the main board, and an acrylic resin board serving as a sub board is laminated thereon.

Here, in order not to distort the image after passing through the polarizing member 18, the first support plate 30 and the second support plate 38 may use support plates with flat surfaces. In addition, the first support plate 30 and the second support plate 38 may use a support plate with a low retardation that does not cause a retardation of the transmitted light so as not to scatter the light (polarized light) transmitted through the polarizing member 18 .

Further, on the first support plate 30 and the second support plate 38, a hard coat (Hard Coat, HC) capable of imparting scratch resistance, an anti-glare layer (Anti-Glare, AG), an anti-reflection layer (Anti-Glare, AG) can be provided - Surface functional layers such as Reflection, AR) and Low-Reflection (LR) layers.

Among them, in order to suppress warping (bending) of the polarizing member 18 due to thermal stress, as described below, when these sub-plates or surface functional layers are provided, the polarizing member 18 can have a vertically symmetrical structure along the film thickness direction of the polarizing member 18. .

In addition, by supporting the front and rear surfaces of the polarizing plate 34 by the first supporting plate 30 and the second supporting plate 38, the mechanical strength of the polarizing member 18 can be improved.

Furthermore, the polarizing plate 34 is sandwiched by the first support plate 30 and the second support plate 38 so as to face each other in the film thickness direction from the front side and the back side, thereby suppressing the application of thermal stress to the polarizing member. Warpage occurs at 18. That is, when the polarizing member 18 is heated due to irradiation of light from the developing device 12 or sunlight from the outside, by making the interface between the surface side of the polarizing plate 34 and the first support plate 30 The generated stress is balanced with the stress generated at the interface between the rear surface side of the polarizing plate 34 and the second support plate 38 , so that warpage (bending) or deformation of the polarizing member 18 can be suppressed. Such a configuration can produce advantageous effects especially in the HUD device 100 for a vehicle that requires heat resistance.

Moreover, the polarizing member 18 may be set as the structure which laminated|stacked the some polarizing plate 34 so that transmission axes may become parallel with each other via an adhesive layer. At this time, in order to impart strength and rigidity to the polarizing member 18, the polarizing plate 34 preferably has a structure in which a polarizing film is bonded to a base material. In addition, in order to suppress warpage or deformation due to thermal stress, the polarizing plate 34 is preferably laminated with the same polarizing plate.

In addition, the first support plate 30, the second support plate 38, the adhesive layers 32 and 36, and the surface functional layer may contain light absorbers such as ultraviolet absorption and infrared absorption.

The light absorber that absorbs ultraviolet rays is added for the purpose of imparting light resistance to the polarizing member 18, reducing ultraviolet rays contained in sunlight, and suppressing discoloration of the polarizing member and resin deterioration. Examples of the ultraviolet absorber include oxybenzophenone-based compounds, benzotriazole-based compounds, salicylate-based compounds, benzophenone-based compounds, cyanoacrylate-based compounds, and nickel zirconium salt-based compounds and other organic UV absorbers. These materials may be used alone, or a plurality of them may be added. The blending ratio of the ultraviolet absorber in the following resin film varies depending on the resin film forming material or the material of the surface functional layer to be used, but is preferably 0.1% by weight or more and 20% by weight or less, more preferably 0.5% by weight or more and 10% by weight or less. When the compounding amount is less than 0.1% by weight, the transmittance at a wavelength of 380 nm or less cannot be sufficiently lowered, and long-term light resistance cannot be obtained. When the blending amount exceeds 20 wt %, there is a possibility of bleeding from the ultraviolet absorbing layer (the phenomenon that the additive floats on the surface of the film), and the further bleeding becomes a defect in appearance.

The addition of the infrared-absorbing light absorber is to provide a heat insulating layer on the polarizing member 18 , to reduce infrared rays (heat rays) derived from sunlight, and to reduce the temperature rise inside the HUD device 100 due to sunlight. The heat insulating layer is a layer containing a material having the property of reducing infrared rays (preventing them from transmitting them), and is roughly classified into an absorbing type that absorbs infrared rays and a reflective type that reflects infrared rays. It is preferable to apply either the absorption type or the reflection type to the polarizing member 18, so that there is less coloration in the visible light region, and the transparency is excellent. For the heat insulating layer, the adhesive layers 32 and 36 constituting the polarizing member 18 may contain a material having heat insulating properties, or a film of a material having heat insulating properties may be formed on the surface of any film constituting the polarizing member 18 to provide the heat insulating layer. .

[Optical characteristics of polarizing member] The transmittance of the polarizing member 18 can be set in accordance with the balance between the light shielding effect of external light such as sunlight and the light amount (luminance of the emitted light) of the polarized light emitted from the liquid crystal. Taking these effects into consideration, the natural light transmittance of the polarizing member 18 is preferably 30% or more and 50% or less, more preferably 35% or more and 45% or less, and particularly preferably 37.5% or more and 42.5% or less. That is, the linearly polarized light transmittance of the polarizing member 18 corresponding to this is preferably 60% or more and 95% or less, more preferably 70% or more and 90% or less, and particularly preferably 75% or more and 85% or less. When the natural light transmittance is less than 30%, although the shading effect of external light such as sunlight increases, the amount of light emitted from the display device may be blocked, and sufficient display brightness cannot be obtained. Conversely, when the natural light transmittance exceeds 50%, although higher display luminance can be obtained, the shielding effect of external light becomes weaker.

The natural light transmittance can be measured by, for example, V-7100 manufactured by JASCO Corporation and U-4100 manufactured by Hitachi, Ltd. Specifically, a polarizing plate was produced, and the transmittance when one sheet of the polarizing plate was used was set as the single transmittance Ys, and the transmittance when two sheets of the polarizing plate were superimposed so that the absorption axis direction was the same was set as the transmittance Ys. As the parallel-position transmittance Yp, the transmittance in the case where two polarizing plates are superimposed so that the absorption axis direction is perpendicular is referred to as the perpendicular-position transmittance Yc. For each transmittance, spectral transmittance τλ is obtained at every predetermined wavelength interval dλ (here, 5 nm) in the wavelength region of 400 nm to 700 nm, and is calculated according to the formula (1). In formula (1), Pλ represents the spectral distribution of standard light (C light source), yλ represents a 2-degree field of view color-matching function, and τλ represents spectral transmittance.

The transmittance of linearly polarized light is the transmittance obtained by making absolutely polarized light incident on a polarizing plate and measuring such that the vibration direction of the absolutely polarized light is perpendicular to the direction of the absorption axis of the polarizing plate of the present embodiment, and is expressed as is the absolute parallel transmittance Ky. Here, the absolute parallel transmittance Ky can be obtained by substituting the single transmittance Ys and the perpendicular position transmittance Yc obtained in the above into the formula (2). In addition, the absolute parallel transmittance Ky can be obtained, for example, only at a predetermined wavelength of each wavelength from 400 nm to 700 nm according to the design of the display device or the waveform characteristics of the polarizing plate, and can also be expressed as the average value of the predetermined wavelength range. .

[Configuration of polarizing member and developing device] When the polarizing member (polarizing case cover) 18 is mounted on the HUD device 100 , the horizontal direction polarized light (S polarized light) that is output from the developing device 12 and transmits the polarizing member 18 and the transmission axis of the polarizing plate 34 of the polarizing member 18 become configured in parallel. At this time, the light emitted from the developing device 12 is the maximum, and the image (virtual image) displayed on the projection unit 20 has the maximum luminance.

Thereby, it is possible to provide the polarizing member 18 which can significantly reduce the light (sunlight or the like) incident on the polarizing member 18 from the outside of the HUD device 100 and can transmit most of the light output by the imager 12 . Therefore, in this case, it is possible to realize the HUD device 100 which is excellent in the brightness and quality of the image when the polarized sunglasses are not worn.

In addition, when wearing polarized sunglasses, as a method of obtaining the brightness of the image, in the above-mentioned arrangement, at least one layer is arranged, for example, on the optical path from the display 12 to the polarizing member 18, or on the output side of the polarizing member 18. The retardation plate called λ/2, λ/4 (λ represents the wavelength), or a retardation plate with a high retardation value of 3000nm to 10000nm or more. As this retardation plate, for example, a stretched film containing resins such as polycarbonate and polyester, or a retardation plate obtained by coating and orienting a polymer liquid crystal material on a substrate can be used.

At this time, the slow axis of the retardation plate is arranged so as to be in a relationship other than the parallel direction and the vertical direction with respect to the polarization direction emitted by the polarizing member 18 or the developing device 12 . This optical axis relationship is to convert a part of the emitted S-polarized light component into a P-polarized light component (vertical polarization), that is, to convert a linearly polarized light component into an elliptically polarized light component, so that even when wearing polarized sunglasses , the polarized sunglasses do not absorb all the light, so the image of the projection unit 20 can be viewed.

In addition, when the retardation plate is arranged in the optical path, by adjusting the arrangement of the slow axis angle of the retardation plate, and further adjusting the optical axis arrangement of the polarizing plate 34, the amount of light emitted from the developing device 12 can be adjusted. become the largest.

On the other hand, the use of the P-polarized light component is a major factor in the deterioration of image quality, such as a problem of image ghosting or a decrease in image brightness when polarized sunglasses are not worn. Therefore, in general, it is desirable to design the relationship between the retardation value of the retardation plate and the aforementioned optical axis in consideration of the balance between the S-polarized light component and the P-polarized light component emitted from the polarizing member 18 .

In addition to the above, in the system in which the polarizing member 18 is mounted on the HUD device 100 , as a method for obtaining the brightness of an image when wearing polarized sunglasses without disposing a retardation plate on the optical path, it is possible to use The direction of the transmission axis of the polarizing member 18 is arranged so that the direction of the polarized light to be emitted becomes a relationship other than the parallel direction and the vertical direction.

That is, as shown in FIG. 5, in the HUD device 100, the polarization direction of the image output from the display device 12 and the transmission axis T of the polarizing member 18 (the axis deviated by 90° from the absorption axis) are formed. The angle is an angle other than the angles of the parallel direction H and the vertical direction V. As shown in FIG. In addition, in FIG. 5, the advancing direction of the image light output from the developing device 12 is set as the direction perpendicular|vertical to the paper surface.

Specifically, the angle θ formed by the transmission axis T of the polarizing member 18 with respect to the polarization direction (parallel direction H) of the image output by the developing device 12 is preferably an angle of 1° or more and 45° or less It is arranged so as to be 5° or more and 45° or less, more preferably. The angle θ is more preferably arranged within a range of 10° or more and 30° or less, from the viewpoint of taking into account the brightness of the polarized sunglasses with and without the polarized sunglasses. In addition, the angle θ is the direction of the transmission axis of the polarizing plate 34 at 0°, the direction counterclockwise from the transmission axis T is represented by a positive value, and the direction clockwise from the transmission axis T is represented by a negative value (minus). :-)Express. In the present disclosure, the notation of positive and negative values of the angle θ is in principle the same.

When the angle θ is in the range of 1° or more and 4° or less, when the polarized sunglasses are worn, a sufficient brightness of the video cannot be obtained, and it becomes difficult to see the video clearly. Furthermore, when the angle θ exceeds 45°, the brightness of the image decreases conversely when the polarized sunglasses are worn, and the luminance of the image decreases when the polarized sunglasses are not worn.

As described above, in order to ensure the brightness when wearing polarized sunglasses, the angle θ other than the angle between the parallel direction H and the vertical direction V can be used, and it is preferable to use the same as the case where the retardation plate is used on the optical path. The arrangement of the angle θ is designed in consideration of the balance between the S-polarized light component and the P-polarized light component finally emitted by the projection unit 20 . In addition, from the viewpoint of balancing the brightness and quality of images with and without polarized sunglasses, the angle θ is preferably arranged so as to be close to the parallel direction so as to utilize more S-polarized light components. side.

Furthermore, in consideration of the deformation of the polarizing member 18 due to thermal stress in the use of the HUD device 100 in a vehicle or the like, the optical axis direction of the polarizing plate 34 may be arranged closer to the parallel direction. Thereby, since the symmetry of the thermal shrinkage direction of the polarizing member 18 can be maintained, the occurrence of distortion of the polarizing member 18 due to thermal deformation can be reduced.

In addition, since the polarizing plate 34 is a polymer uniaxially stretched PVA film, it can be operated as a retardation plate having optical anisotropy similarly to the above-mentioned retardation plate. That is, the effect obtained by the angle θ of the polarizing plate 34 can be expressed numerically as the retardation value (Re) in the polarizing film of the polarizing plate 34 . However, the measurement of the retardation value of the polarizing film of the polarizing plate 34 is performed by a retardation measuring apparatus (for example, KOBRA-WPR manufactured by Oji Measurement Co., Ltd., etc.), but it is difficult in principle. Therefore, in order to estimate the retardation value, a PVA film containing no dichroic dye is produced under the same production conditions as the polarizing film of the polarizing plate 34, or a polarizing plate having a lower polarization characteristic that has less influence on the aforementioned measurement is used. Carry out the measurement. As an example of the above-mentioned polarizing plate, the high-transmittance dye-based polarizing plate SHC-10UE (70) manufactured by Polaris Technology Co., Ltd. (a polarizing film sandwiched by a TAC base material, visual sensitivity corrected transmittance Ys=70%, visual sensitivity Corrected polarization degree Py=29%). The retardation value Re(550) at a wavelength of 550 nm of the polarizing film of the polarizing plate 34 was calculated to be 550 nm from the measurement of the retardation value of the polarizing plate. At this time, the influence caused by the TAC substrate cannot be ignored optically. This value implies that the polarizing plate 34 plays a small role as a retardation plate.

Therefore, from the above calculation result, the retardation value of the polarizing film of the polarizing plate 34 can be expressed as follows. The retardation value (Re(550)) at a wavelength of 550 nm possessed by the polarizing film in the polarizing member 18 with respect to the polarized light of the image output by the developing device 12 can be set to n×550±150 nm (n is 0 , 1, 2･･･). Here, ±150 nm is a value obtained in consideration of the tolerance range of the retardation value, and the tolerance range of the retardation value takes into account the effect and wavelength dispersion characteristics of the retardation plate. By constituting a light plate having a polarizing film whose Re(550) is the above-mentioned value, the effect as a retardation plate is small, and the effect of suppressing wavelength-dependent coloring can be further brought about.

The polarizing member 18 having the above-mentioned angle θ can be produced, for example, by cutting the polarizing plate 34 so as to have a predetermined optical axis relationship, and then laminating the first support plate 30 and the second support plate 38, etc., or in the form of a roll or sheet. Then, the polarizing member 18 is performed by punching (Thomson processing) using a die.

[Application Example 1] As the polarizing plate 34 of the polarizing member 18 , an achromatic polarizing plate (also referred to as an “achromatic polarizing plate”) can be used, which has a wavelength range (380 nm to 780 nm, especially 400 nm to 700 nm) over the visible light wavelength region. , the transmittance at this wavelength is almost uniform. In addition, the properties of the polarizing plate can be measured from, for example, the transmittances of Ys, Yp, and Yc, and can be expressed using hue values (a ^{* , b* ) in the L*} a ^* b ^{* color system.} In the achromatic polarizing plate, in consideration of durability and ease of hue adjustment, the dichroic dye forming the polarizing plate can be composed of a dye-based material designed for use in an achromatic polarizing plate. Thereby, the coloring of the image of the projection unit 20 due to the plurality of polarizers being arranged in parallel on the optical path is reduced, and the projection unit 20 can approach the color tone of the original image output from the developing device 12 .

The following dyes can be exemplified as an azo compound dye that is appropriately designed as a dye-based material for the achromatic polarizing plate.

(式中，Ag₁ 表示可具有取代基的苯基或具有取代基的萘基，Bg和Cg各自獨立地由化學式9(BC-N)或化學式10(BC-P)表示，兩方或其中一方表示式(BC-N)，Xg₁ 表示可具有取代基的胺基、可具有取代基的苯胺基、可具有取代基的苯甲醯胺基、可具有取代基的萘并三唑、或可具有取代基的苯基偶氮基)

(式中，Rg₁ 表示氫原子、碳數1～5的烷基、碳數1～5的烷氧基、或具有磺基的碳數1～5的烷氧基，k表示0～2的整數)

(Rg₂ 和Rg₃ 各自獨立地表示氫原子、碳數1～5的烷基、碳數1～5的烷氧基、或具有磺基的碳數1～5的烷氧基)The azo compound represented by chemical formula (8) or a salt thereof disclosed in Japanese Republished Patent WO2017/146212(A1).

(in the formula, Ag ₁ represents a substituted phenyl group or a substituted naphthyl group, and Bg and Cg are each independently represented by Chemical Formula 9 (BC-N) or Chemical Formula 10 (BC-P), and both or wherein One side represents the formula (BC-N), Xg ₁ represents an optionally substituted amine group, an optionally substituted aniline group, an optionally substituted benzamide group, an optionally substituted naphthotriazole, or optionally substituted phenylazo)

(wherein, Rg ₁ represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, or an alkoxy group having a sulfo group having 1 to 5 carbon atoms, and k represents 0 to 2 integer)

(Rg ₂ and Rg ₃ each independently represent a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, or an alkoxy group having a sulfo group having 1 to 5 carbon atoms.)

(式中，AR₁ 表示具有取代基的苯基或具有取代基的萘基，R_r1 ～R_r4 各自獨立地表示氫原子、碳數1～4的烷基、碳數1～4的烷氧基、或具有磺基的碳數1～4的烷氧基，j表示0或1，X_r1 表示可具有取代基的胺基、可具有取代基的苯胺基、可具有取代基的苯基偶氮基、可具有取代基的苯甲醯基、或可具有取代基的苯甲醯胺基)The azo compound represented by chemical formula (11) or a salt thereof disclosed in International Publication WO2019/117131(A1).

(In the formula, AR ₁ represents a substituted phenyl group or a substituted naphthyl group, and R _r1 to R _r4 each independently represent a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, and an alkoxy group having 1 to 4 carbon atoms. group, or an alkoxy group having a sulfo group and having 1 to 4 carbon atoms, j represents 0 or 1, and X _r1 represents an amino group which may have a substituent, an aniline group which may have a substituent, a phenyl coupler which may have a substituent Nitrogen, optionally substituted benzyl, or optionally substituted benzamide)

[Application example 2] When the polarizing member 18 has a structure in which a plurality of polarizing plates 34 are laminated with an adhesive layer interposed therebetween, at least one of the polarizing plates 34 on the output side of the projection unit 20 (outside of the HUD device 100 ), The transmission axis is arranged so as to be the above-mentioned angle θ. Thereby, even if the polarizing member 18 is formed by laminating a plurality of polarizing plates 34 with an adhesive layer interposed therebetween, the brightness of an image can be obtained when wearing polarized sunglasses. [Example]

Hereinafter, the method for confirming the brightness of the HUD display image when the polarized sunglasses are worn will be described in detail.

[Example 1] As the polarizing plate 34 used in the polarizing member 18 , a dye-based polarizing plate EHC-125U manufactured by Polaris Technology Co., Ltd. (susceptibility corrected transmittance Ys=40.0%, apparent sensitivity corrected polarization degree Py=99.5%) was used. Next, as shown in FIG. 6, a commercially available color in-plane switching (IPS) liquid crystal display (hereinafter referred to as “LCD”) serving as the developing device 12 is placed flat upward, and tilted at 45° above it. The blue plate glass 50 (thickness 1.1 mm) was installed so that the display image of the LCD could be observed on the surface of the blue plate glass 50 as a virtual image. At this time, the blue plate glass 50 is installed at a position where the polarized light emitted from the LCD is projected horizontally so that the luminance of the virtual image projected on the glass plate becomes the maximum. Further, a polarizing plate EHC-125U as the polarizing housing cover 18 is provided on the LCD. At this time, the transmission axis of the polarizing case cover 18 is set to be 5° (angle θ=5°) with respect to the transmission axis of the polarizing layer on the front side (exit side) of the LCD.

As will be described below, the brightness of the virtual image of the blue plate glass 50 is performed based on the sensory evaluation of the observer. The observer is arranged at a position where the virtual image of the blue plate glass 50 can be observed so as to assume an arrangement relationship of the HUD device 100 of the vehicle. Here, an iodine-based polarizing plate SKN-18243 manufactured by Polaris Technology Co., Ltd., which is an absorption-type polarizing plate 52 (viewing sensitivity corrected transmittance Ys= 43%, visual sensitivity correction polarization degree Py=99.9%), the brightness of the virtual image on the surface of the blue plate glass 50 is confirmed by the observer, and the polarizing plate can perform the same function as polarized sunglasses.

The luminance of the virtual image of the blue plate glass 50 was measured by lighting a white image on the LCD, and the virtual image projected on the blue plate glass 50 was measured using a two-dimensional color luminance meter CA-2000 manufactured by Konica Minolta. Without arranging the polarizing plate 52 (polarizing plate SKN-18243) as a substitute for polarized sunglasses, the luminance under the condition of angle θ=0° was set to 100, and the luminance with and without the polarizing plate 52 was compared.

[Example 2] The same as Example 1 except that the transmission axis of the polarizing case cover 18 is set to be 15° (angle θ=15°) with respect to the transmission axis of the polarizing layer on the front side (exit side) of the LCD.

[Example 3] The same as Example 1 except that the transmission axis of the polarizing case cover 18 is set to be 30° (angle θ=30°) with respect to the transmission axis of the polarizing layer on the front side (exit side) of the LCD.

[Example 4] The same as Example 1 except that the transmission axis of the polarizing case cover 18 is set to be 45° (angle θ=45°) with respect to the transmission axis of the polarizing layer on the front side (exit side) of the LCD.

[Comparative Example 1] The same as Embodiment 1 except that the transmission axis of the polarizing case cover 18 is set parallel to the transmission axis of the polarizing layer on the front side (exit side) of the LCD (angle θ=0°).

[Comparative Example 2] The same as Example 1 except that the transmission axis of the polarizing case cover 18 is set to be 2° (angle θ=2°) with respect to the transmission axis of the polarizing layer on the front side (exit side) of the LCD.

[Comparative Example 3] The same as Example 1 except that the transmission axis of the polarizing case cover 18 is set to be 60° (angle θ=60°) with respect to the transmission axis of the polarizing layer on the front side (exit side) of the LCD.

[Table 1]

As shown in Table 1, in the case of Examples 1 to 4 in which the transmission axis of the polarizing case cover 18 is set to be 5° to 45° with respect to the transmission axis of the polarizing layer on the front side (outgoing side) of the LCD, even if the transmission axis is arranged When the polarizer 52 is used, the virtual image can also be viewed. In addition, as shown in Comparative Examples 1 and 2, when the angle θ is less than 5°, even when the polarizing plate 52 is arranged, the brightness of the virtual image cannot be sufficiently obtained, and it is difficult to view the virtual image. In addition, when the angle θ of Comparative Example 3 was 60°, the virtual image could be viewed with or without the polarizer 52 , but the brightness of the virtual image was greatly reduced without the polarizer 52 . Therefore, when designing the HUD device 100 including the polarizing case cover 18 to be compatible with polarized sunglasses, it is necessary to make it possible to achieve both brightness and development quality with and without polarized sunglasses. the angle θ.

As can be seen from the above, according to the HUD device 100 of the present disclosure, a head-up display can be provided, which can reduce the incidence of sunlight into the device, and without using a retardation plate in the HUD device 100 and the light-transmitting case cover, Display images can be viewed even when wearing polarized sunglasses. In addition, since it is not necessary to arrange a new optical member in the HUD device 100, the HUD device 100 corresponding to polarized sunglasses can be easily produced by simply adjusting the arrangement of the light-transmitting cover.

10: Frame 12: Monitor 14: Flat mirror 16: Concave mirror 18: Polarizing member 20: Projection Department 30: 1st support plate 32: Adhesive layer 34: polarizer 36: Adhesive layer 38: 2nd support plate 50: blue plate glass 52: polarizer

FIG. 1 is a diagram showing a configuration of a head-up display device in an embodiment of the present disclosure. FIG. 2 is a diagram showing the configuration of a head-up display device in another embodiment of the present disclosure. FIG. 3 is a diagram showing the configuration of the polarizing member in the embodiment of the present disclosure. FIG. 4 is a diagram showing the configuration of a polarizing member in another embodiment of the present disclosure. FIG. 5 is a diagram showing the relationship between the polarization direction of the image and the transmission axis of the polarizing member in the embodiment of the present disclosure. FIG. 6 is a diagram showing a test configuration in an example of the present disclosure.

Domestic storage information (please note in the order of storage institution, date and number) none Foreign deposit information (please note in the order of deposit country, institution, date and number) none

10: Frame

12: Monitor

14: Flat mirror

16: Concave mirror

18: Polarizing member

20: Projection Department

Claims (4)

A head-up display having: a polarizing member, comprising a polarizing layer and a support plate disposed on at least one side of the polarizing layer; a developing device, the output of which is an image comprising a linearly polarized light component; and, a frame body, which accommodates the aforementioned developing device; The polarizing member is used as a light-transmitting case cover, and the light-transmitting case cover transmits the image to the outside of the frame body, The angle formed by the transmission axis of the polarizing layer and the polarization direction of the image output by the developing device is set to exclude the parallel and vertical angles, The above-mentioned image transmitted through the above-mentioned polarizing member is projected as a projected image by a virtual image including polarized light in a horizontal direction and a vertical direction. The head-up display according to claim 1, wherein the transmission axis of the polarizing layer is 5 to 45 degrees with respect to the polarization direction of the image output by the display device. The head-up display according to claim 1, wherein the polarizing film of the polarizing layer has a retardation value (Re) at a wavelength of 550 nm with respect to the polarized light of the image output by the imaging device is n× 550±150nm, n is an integer of 0, 1, 2･･･. The head-up display according to claim 2, wherein the polarizing film of the polarizing layer has a retardation value (Re) at a wavelength of 550 nm with respect to the polarized light of the image output by the imaging device is n× 550±150nm, n is an integer of 0, 1, 2･･･.

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