Head-up display apparatus reducing sunlight reflection

Abstract

One aspect of the present invention relates to a head-up display apparatus reducing sunlight reflection and, more specifically, to a head-up display apparatus which effectively reduces sunlight reflection and enables a signal light emitted from a display module to smoothly reach an eyebox of a user. According to one embodiment of the present invention, provided may be a head-up display apparatus which reduces sunlight directed to an eyebox of a user by converting a polarization state of light and enables signal light emitted from a display module to smoothly reach the eyebox of the user. In addition, according to one embodiment of the present invention, provided may be a head-up display apparatus which minimizes sunlight directed to an eyebox of a user and maximizes signal light emitted from a display module by adjusting the rotation characteristics and retardation characteristics of a first retarder coupled to a polarizer and a second retarder coupled to the display module.

Description

Head-up display device that reduces sunlight reflection

[0001] One aspect of the present invention relates to a head-up display device that reduces sunlight reflection, and more specifically, to a head-up display device that effectively reduces sunlight reflection while enabling signal light rays generated from a display module to smoothly reach the user's eye box.

[0002] The content described in this section merely provides background information regarding embodiments of the present invention and does not constitute prior art.

[0003] A Head-Up Display (HUD) primarily projects and provides necessary information in the direction of the driver's or pilot's line of sight within automobiles, aircraft, and other vehicles. Conventional HUDs consist of a display module, an optical system, and a reflective mirror, and they project signal light emitted from the display module directly into the user's field of vision (eyebox) through the reflective mirror.

[0004] These head-up display devices enhance information visibility and minimize driver distraction. However, existing devices suffer from a problem where the readability of the display is significantly degraded by reflection from strong external light sources, such as sunlight.

[0005] Figure 1 illustrates the process of reflected sunlight reaching the user's eye box.

[0006] Referring to FIG. 1, a portion of the sunlight (A) passes through the windshield (10) of the vehicle and enters the head-up display device (300) with an angle of incidence (AOI), is Fresnel reflected from the surface of the display device, and is again Fresnel reflected from the windshield (10) and directed directly toward the eyebox (20), which is the driver's field of vision. Here, the user may refer to the driver of the vehicle.

[0007] Since the path of this solar ray (A) overlaps with the function of the head-up display device, it may interfere with the purpose of the head-up display to display information and obstruct the field of view.

[0008] Figure 2(a) is a diagram showing the diameter of the sun (D) and the distance from the sun to the earth (L). Here, using the diameter of the sun (D) and the distance from the sun to the earth (L), the angular size of the sun can be calculated using the arctangent function (arctan(D / L)). As a result, in Figure 2(a), it was calculated to be approximately 0.5 degrees (deg).

[0009] Figure 2(b) is a diagram showing how the image of the sun is formed after it is captured by the eye.

[0010] When sunlight reaches the user's eyes, the sun appears to the eyes with an angular size of about 0.5 degrees. This angular size refers to the size of the image of the sun formed on the retina of the eye and is equal to the angular size calculated in Figure 2(a) above.

[0011] Figure 3(a) is a diagram showing the process of sunlight being reflected off a flat panel surface and entering the user's eye, and Figure 3(b) is a diagram showing the process of sunlight being reflected off a lenticular lens surface and entering the user's eye.

[0012] Referring to Fig. 3(a), when sunlight is reflected by a flat surface, the sun appears to the user's eye with an angular size of about 0.5 degrees and is perceived as a single bright spot. However, referring to Fig. 3(b), when sunlight is reflected by a lenticular lens, the concentrated light of the sunlight is dispersed in one direction and is perceived as a bright line.

[0013] Therefore, the information the driver sees through the head-up display may be obscured or blurred by reflected sunlight. In particular, this problem can be more severe in 3D augmented reality head-up display devices that use lenticular lenses.

[0014] Since reflected sunlight entering the driver's field of vision can seriously affect safety while driving, the development of a new type of head-up display device to resolve this issue is required.

[0015] The aforementioned background technology is technical information that the inventor possessed or acquired during the process of deriving the embodiments of the present invention, and it cannot be considered as prior art disclosed to the general public prior to the filing of the embodiments of the present invention.

[0016] Accordingly, one aspect of the present invention is proposed to solve the aforementioned problems, and the objective of the present invention is to provide a head-up display device that reduces sunlight by converting the polarization state of the light rays, while allowing signal light rays emitted from a display module to smoothly reach the user's eye box.

[0017] The technical problems that the present invention aims to solve are not limited to those mentioned above, and other unmentioned technical problems will be clearly understood by those skilled in the art to which the present invention belongs from the description below.

[0018] To achieve the above-mentioned objectives, one aspect of the present invention comprises: a dust cover that controls and manipulates the polarization state of sunlight to reduce sunlight directed toward a user's eye box; and

[0019] A display module that controls and manipulates the polarization state of a signal light to allow the signal light to smoothly pass through the dust cover and reach the eye box;

[0020] A head-up display device including one or more of the above can be provided.

[0021] The dust cover may be characterized by having a concave shape to prevent sunlight reflected from its surface from being transmitted to the user's eye box.

[0022] The dust cover may be characterized by having a polarizer and a first retarder, and the display module may be characterized by having a second retarder.

[0023] The first delay device may be disposed on the lower surface of the polarizer of the dust cover.

[0024] The display module may be characterized by having a display panel and an optical layer that is laminated on the upper surface of the display panel and forms a three-dimensional image, and the second delayer may be positioned between the optical layer and the display panel.

[0025] The above optical layer may be characterized by including a first layer and a second layer having different refractive indices.

[0026] The surface of the above optical layer may be characterized by having an anti-reflection coating formed thereon.

[0027] The first delay device and the second delay device may be characterized by converting a linearly polarized light into a circularly polarized light or vice versa.

[0028] According to an embodiment, the polarizer may be characterized by including an S-polarizer.

[0029] When the above display module has a P-polarizing panel, the first delay and the second delay may be characterized by having a fast axis in the same direction.

[0030] The first delay device and the second delay device may both be characterized by including a Quarter Wave Film (QWF).

[0031] The rotation property of the fast axis of the quarter wave film may be characterized by having 45 degrees (deg) or -45 degrees (deg) relative to the vertical polarization axis.

[0032] When the above display module has an S-polarizing panel, the first delay and the second delay may be characterized by having fast axes in different directions.

[0033] The first delay device and the second delay device may both be characterized by including a Quarter Wave Film (QWF).

[0034] The rotation property of the fast axis of the quarter wave film may be characterized in that the first delay and the second delay are each 45 degrees (deg) and -45 degrees (deg) with respect to the vertical polarization axis, or -45 degrees (deg) and 45 degrees (deg).

[0035] According to an embodiment, the polarizer may be characterized by including a P-polarizer.

[0036] It may be characterized by having a P-Polarization Reflective Coating formed on a windshield positioned on the upper part of the dust cover.

[0037] When the above display module has an S-polarizing panel, the first delay and the second delay may be characterized by having a fast axis in the same direction.

[0038] The first delay device and the second delay device may both be characterized by including a Quarter Wave Film (QWF).

[0039] The rotation property of the fast axis of the quarter wave film may be characterized by having 45 degrees (deg) or -45 degrees (deg) relative to the vertical polarization axis.

[0040] When the above display module has a P-polarizing panel, the first delay and the second delay may be characterized by having fast axes in different directions.

[0041] The first delay device and the second delay device may both be characterized by including a Quarter Wave Film (QWF).

[0042] The rotation property of the fast axis of the quarter wave film may be characterized in that the first delay and the second delay are each 45 degrees (deg) and -45 degrees (deg) with respect to the vertical polarization axis, or -45 degrees (deg) and 45 degrees (deg).

[0043] The above polarizer may be selected from an S-polarizer or a P-polarizer, and the display module may be characterized by being selected from an S-polarizing panel or a P-polarizing panel.

[0044] It may be characterized by adjusting the rotation property and retardation property of the first delay device in correspondence with the selected polarizer and the selected display module.

[0045] It may be characterized by adjusting the rotation property and retardation property of the second delay device in correspondence with the first delay device adjusted above.

[0046] The adjustment of the first delay device and the adjustment of the second delay device may each be characterized by being performed through simulation.

[0047] The adjustment of the first delay device may be characterized by finding a minimum value (Min value) for the first delay device, and the adjustment of the second delay device may be characterized by finding a maximum value (Max value) for the second delay device.

[0048] Another aspect of the present invention is a solar light absorption step in which solar light passes through a dust cover and changes its polarization state at least once, is reflected by Fresnel, moves back to the dust cover and changes its polarization state at least once, and is then absorbed by the dust cover;

[0049] A signal light emission step in which a signal light emitted from a display panel passes through the dust cover and changes its polarization state at least once while reaching the user's eye box;

[0050] A display method for reducing solar reflection including one or more of the following can be provided.

[0051] The absorption step may be characterized by changing its polarization state four times, and the emission step may be characterized by changing its polarization state two times.

[0052] The polarization state of the absorption step described above may be characterized in that the solar rays are first linearly polarized, first circularly polarized, second circularly polarized, and second linearly polarized.

[0053] The first linear polarization and the second linear polarization may be characterized as being P-polarization and S-polarization, or S-polarization and P-polarization, respectively.

[0054] The first circular polarization and the second circular polarization may be characterized as being left-handed circular polarization (LHCP) and right-handed circular polarization (RHCP), respectively, or right-handed circular polarization and left-handed circular polarization.

[0055] The polarization state of the above emission step may be characterized in that the signal light is converted from a first linear polarization to circular polarization, and then converted again to a second linear polarization.

[0056] When the first delay device converting from the first linear polarization to circular polarization and the second delay device converting from the circular polarization to the second linear polarization are in the same direction, the first linear polarization and the second linear polarization may be characterized as being P-polarization and S-polarization, or S-polarization and P-polarization, respectively.

[0057] When the first delay device converting from the first linear polarization to circular polarization and the second delay device converting from the circular polarization to the second linear polarization are in different directions, the first linear polarization and the second linear polarization may be characterized in that both are P-polarization or both are S-polarization.

[0058] Another aspect of the present invention is an incident step in which sunlight passing through a dust cover is first linearly polarized and then first circularly polarized during the process of passing through the dust cover;

[0059] A reflection step in which the first circularly polarized sunlight is reflected by a display module to become a second circularly polarized light in the opposite direction to the first circular polarization;

[0060] An emission step in which the second circularly polarized sunlight is polarized into a second linearly polarized light having a direction different from the first linear polarization; and

[0061] An absorption step in which the second linearly polarized sunlight is absorbed by the dust cover;

[0062] A method for reducing solar radiation including can be provided.

[0063] In the above incident step, the first linear polarization may be performed by a polarizer, and the first circular polarization may be performed by an upper first delay device.

[0064] In the above-mentioned output step, the second linear polarization may be characterized by being performed by the upper first delay device.

[0065] The above absorption step may be characterized by being performed by a polarizer.

[0066] Another aspect of the present invention is a conversion step in which a signal light emitted from a display module is converted from a first linearly polarized state to circularly polarized light;

[0067] A reaching stage in which the circularly polarized signal beam passes through the dust cover, becomes linearly polarized in a direction different from the first linear polarization, is Fresnel-reflected by the windshield, and reaches the user's eye box:

[0068] A signal light output method including can be provided.

[0069] The above conversion step may be characterized by being performed by a lower second delay device.

[0070] The above reaching step may be characterized by being performed by the upper first delay device.

[0071] Another aspect of the present invention is a display module having a display panel and an optical layer laminated on the upper surface of the display panel and forming a three-dimensional image; and

[0072] A dust cover disposed on the upper surface of the above-mentioned display module; including,

[0073] The dust cover has a shape that prevents a first reflected light transmitted to the user's eye through Fresnel reflection, and a head-up display device having a polarizer and a cover retarder to reduce a second reflected light that passes through the dust cover and is reflected from the surface of the optical layer can be provided.

[0074] As described above, according to one embodiment of the present invention, a head-up display device can be provided that converts the polarization state of light rays to reduce sunlight directed toward the user's eye box while allowing signal light rays emitted from the display module to smoothly reach the user's eye box.

[0075] In addition, the present invention has various effects, such as excellent versatility depending on the embodiment, and such effects can be clearly confirmed in the description of the embodiment below.

[0076] The following drawings attached to this specification illustrate an embodiment of the present invention and serve to further enhance understanding of the technical concept of the present invention together with the detailed description of the invention described above; therefore, the present invention should not be interpreted as being limited only to the matters described in such drawings.

[0077] Figure 1 illustrates the process of reflected sunlight reaching the user's eye box.

[0078] Figure 2(a) is a diagram showing the diameter (D) of the sun, the distance (L) from the sun to the earth, and the angle of incidence to the earth, and Figure 2(b) is a diagram showing how the image of the sun is formed after being captured by the eye.

[0079] Figure 3(a) is a diagram showing the process of sunlight being reflected off a flat panel surface and entering the user's eye, and Figure 3(b) is a diagram showing the process of sunlight being reflected off a lenticular lens surface and entering the user's eye.

[0080] FIG. 4 shows a head-up display device including a dust cover and a display module according to one embodiment of the present invention.

[0081] Figure 5 is a diagram showing sunlight reflected from the display module of a flat head-up display device directed toward the user's eye box.

[0082] FIG. 6 shows a head-up display device in which the polarizer of a dust cover according to one embodiment of the present invention is an S-polarizer.

[0083] Figure 7 shows the configuration of the display module in the head-up display device of Figure 6.

[0084] Figure 8 shows the polarization state of a signal light beam when the polarizer of the dust cover is an S-polarizer and the display panel of the display module is a P-polarizer.

[0085] Figure 9 shows the polarization state of a signal light beam when the polarizer of the dust cover is an S-polarizer and the display panel of the display module is an S-polarizing panel.

[0086] FIG. 10 shows a head-up display device in which the polarizer of the dust cover according to one embodiment of the present invention is a P-polarizer.

[0087] Figure 11 shows the configuration of the display module in the head-up display device of Figure 10.

[0088] Figure 12 shows the polarization state of a signal light beam when the polarizer of the dust cover is a P-polarizer and the display panel of the display module is an S-polarizer panel.

[0089] Figure 13 shows the polarization state of a signal light beam when the polarizer of the dust cover is a P-polarizer and the display panel of the display module is a P-polarized panel.

[0090] Figure 14 shows the change in incident light polarization of an ideal mirror reflection and the Fresnel reflectance for each polarization according to the angle of incidence of the incident light.

[0091] Figure 15 shows the changes in the different polarization characteristics of the incident and emitted light for the case of fold mirror reflection and Fresnel reflection, respectively.

[0092] FIG. 16 illustrates a method for controlling delay characteristics according to one embodiment of the present invention.

[0093] Figure 17 illustrates a method for finding the optimal delay characteristics and rotation characteristics of a first delayer for reducing solar reflection through simulation in the second step of the delayer characteristic control method.

[0094] Figure 18 illustrates a method for finding the optimal delay characteristics and rotation characteristics of a second delayer for signal output through simulation in the third step of the delayer characteristic control method.

[0095] FIG. 19 is a figure showing the solar reflection reduction effect due to the presence or absence of the first delay device according to the present embodiment.

[0096] FIG. 20 is a figure showing the result of signal output according to the use of the second delay device according to the present embodiment.

[0097] Figure 21 is a figure comparing the respective reflection characteristics of a single-layer lenticular lens and a multi-layer lenticular lens having different refractive indices.

[0098] The advantages and features of the present invention, and the methods for achieving them, will become clear by referring to the embodiments described in detail together with the accompanying drawings. However, the present invention is not limited to the embodiments presented below, but can be implemented in various different forms and should be understood to include all modifications, equivalents, and substitutions that fall within the spirit and scope of the present invention. The embodiments presented below are provided to ensure that the disclosure of the present invention is complete and to fully inform those skilled in the art of the scope of the invention. In describing the present invention, detailed descriptions of related known technologies are omitted if it is determined that such detailed descriptions may obscure the essence of the present invention.

[0099] The terms used in this application are used merely to describe specific embodiments and are not intended to limit the invention. The singular expression includes the plural expression unless the context clearly indicates otherwise.

[0100] In this application, terms such as “comprising” or “having” are intended to specify the existence of the features, numbers, steps, actions, components, parts, or combinations thereof described in the specification, and should be understood as not precluding the existence or addition of one or more other features, numbers, steps, actions, components, parts, or combinations thereof. Terms such as “first,” “second,” etc., may be used to describe various components, but the components should not be limited by said terms. These terms are used solely for the purpose of distinguishing one component from another.

[0101] Hereinafter, embodiments according to the present invention will be described in detail with reference to the attached drawings. In describing with reference to the attached drawings, identical or corresponding components are given the same reference numerals, and redundant descriptions thereof are omitted.

[0102] FIG. 4 shows a head-up display device including a dust cover and a display module according to one embodiment of the present invention.

[0103] A head-up display device (100) according to one embodiment of the present invention may be configured to include a dust cover (200) and a display module (300).

[0104] When the head-up display device (100) according to the present embodiment is installed in a vehicle, sunlight (A) passes through the windshield (10) and heads toward the dust cover (200), is Fresnel reflected from the surface of the dust cover (200), and is again Fresnel reflected by the windshield (10), but the angle of reflection changes due to the shape of the dust cover (200) so that it does not head toward the user's eye box (20).

[0105] According to the present embodiment, the shape of the dust cover (200) is designed so that sunlight (A) does not face toward the user's eye box (20), thereby allowing the sunlight (A) to be avoided. The aforementioned effect can be achieved by forming the shape of the dust cover (200) as a concave shape toward the inside of the head-up display device (100).

[0106] Here, only the sunlight (A) reflected from the surface of the dust cover (200) is considered, and the sunlight (A) passing through the dust cover (200) and reaching the display module (300) is not considered. The sunlight (A) passing through the dust cover (200) will be described later.

[0107] A special type of dust cover (200) that prevents sunlight reflected by the eyebox (20) of the present invention can be designed using a forward or backward ray-tracing approach. The backward approach is particularly useful because the position of the eyebox (20) is clearly defined. Subsequently, the shape of the designed dust cover (200) can be verified by a comprehensive ray-tracing simulation. In this case, additional blocks such as light traps can be used.

[0108] Referring to FIG. 5, sunlight (A) that passes through the windshield (10) and the dust cover (200) in sequence can be Fresnel reflected from the surface of the display module (300), pass through the dust cover (200) again, be reflected back to the windshield (10), and then be directed toward the user's eye box (20).

[0109] According to the present embodiment, the shape of the dust cover (200) can be modified so that sunlight (A) reflected from the surface of the dust cover (200) is not directed toward the user's eye box (20). However, sunlight (A) that passes through the dust cover (200) and reflects from the surface of the display module (300) can still be directed toward the user's eye box (20), which becomes a problem during operation.

[0110] A head-up display device (100) according to one embodiment of the present invention includes a dust cover (200) that controls and manipulates the polarization state of sunlight (A) (Sun Light) to reduce sunlight (A) directed toward the user's eyebox (20, Eyebox); and

[0111] It may be configured to include a display module (300) that controls and manipulates the polarization state of a signal light (B) so that the signal light (B) passes smoothly through a dust cover (200) and reaches an eye box (20).

[0112] The dust cover (200) has a polarizer (210) and a first retarder (220), and the display module (300) may have a second retarder (320).

[0113] First, the configuration of the dust cover (200) of the head-up display device (100) according to the present embodiment will be explained first.

[0114] FIG. 6 shows a head-up display device in which the polarizer of a dust cover according to one embodiment of the present invention is an S-polarizer.

[0115] Referring to FIG. 6, a dust cover (200) constituting a head-up display device (100) according to one embodiment of the present invention may be configured to include a polarizer (210) and a first delay device (220). According to the embodiment, the first delay device (220) may be disposed on the lower surface of the polarizer (210) of the dust cover (200).

[0116] In FIG. 6, the polarizer (210) may be a linear polarizer. The linear polarizer may be, for example, an S-polarizer.

[0117] The solar rays (A) pass through the windshield (10) and the S-polarizer of the dust cover (200). During this process, the P-polarized portion of the solar rays (A) is absorbed by the S-polarizer, and only the S-polarized portion passes through the delayer and is converted into circularly polarized solar rays (A). For reference, the term "circular polarization" in this specification includes distorted circular polarization.

[0118] Circularly polarized sunlight (A) is reflected from the surface of the display module (300) and the polarization state is converted to the opposite direction.

[0119] The circularly polarized sunlight (A) in the opposite direction passes through the delayer of the dust cover (200) again and is converted into P-polarized sunlight (A). Then, the P-polarized sunlight (A) is absorbed by the S-polarizer of the dust cover (200) and does not go toward the user's eye box (20).

[0120] Next, the configuration of the display module (300) of the head-up display device (100) according to the present embodiment will be described.

[0121] Figure 7 shows the configuration of the display module in the head-up display device of Figure 6.

[0122] Referring to FIG. 7, a display module (300), which is a component of a head-up display device (100) according to the present embodiment, has a display panel (330) and an optical layer (310) that is laminated on the upper surface of the display panel (330) and forms a three-dimensional image, and a second delay device (320) may be disposed between the optical layer (310) and the display panel (330). Here, the optical layer (310) may include, for example, a lenticular lens.

[0123] The signal light (B) is generated from the P-polarized flat panel (330) of the display module (300) and passes through the second delayer (320) and the lenticular lens (310) in sequence. As the signal light (B) passes through the second delayer (320), the P-polarized signal light (B) is converted into a circularly polarized signal light (B), and after passing through the lenticular lens (310), it passes through the first delayer (220) again and is converted from a circularly polarized signal light (B) into an S-polarized signal light (B). As a result, the S-polarized signal light (B) passes smoothly through the S-polarizer, is Fresnel reflected from the windshield (10), and then enters the user's eye box (20).

[0124] Figure 8 shows the polarization state of a signal light beam when the polarizer of the dust cover is an S-polarizer and the display panel of the display module is a P-polarizer.

[0125] FIG. 8(a) shows the polarization state of a signal light (B) when the first delayer (220) and the second delayer (320) are quarter wave films (Quarter Wave, 0.25 lambda) and the fast axes of the quarter wave films both have a direction of 45 degrees (deg) with respect to the vertical polarization axis, and FIG. 8(b) shows the polarization state of a signal light (B) when the first delayer (220) and the second delayer (320) are quarter wave films and the fast axes of the quarter wave films both have a direction of -45 degrees (deg) with respect to the vertical polarization axis.

[0126] A polarizer (210) of a dust cover (200) according to one embodiment of the present invention may include an S-polarizer.

[0127] Referring to FIG. 8, when the display module (300) has a P-polarizing panel (330, P-pol panel), the first delayer (220) and the second delayer (320) may be configured to have a fast axis in the same direction. According to an embodiment, both the first delayer (220) and the second delayer (320) may include a quarter wave film (QWF). In this case, the rotation property of the fast axis of the quarter wave film constituting the first delayer (220) and the second delayer (320) may be configured to have a rotation direction of 45 degrees (deg) with respect to the vertical polarization axis (see FIG. 8(a)) or to have a rotation direction of -45 degrees (deg) with respect to the vertical polarization axis (see FIG. 8(b)).

[0128] Referring to FIG. 8(a), a P-polarized signal ray (B) emitted from a P-polarized panel (330) passes through a glass layer (331) and a quarter-wave film having a fast axis in the 45-degree (deg) direction, which is a second delayer (320), and is converted from P-polarized to Left-Handed Circular Polarization (LHCP), and then passes through a lenticular lens (310). The Left-Handed Circular Polarized (LHCP) signal ray (B) passes through a quarter-wave film having a fast axis in the 45-degree (deg) direction, which is a first delayer (220), and is converted from Left-Handed Circular Polarization (LHCP) to S-polarized, and the S-polarized signal ray (B) passes through an S-polarizer, is reflected from a windshield (10), and finally heads toward the user's eye box (20).

[0129] Referring to FIG. 8(b), a P-polarized signal ray (B) emitted from a P-polarized panel (330) passes through a glass layer (331) and a quarter-wave film having a fast axis in the direction of -45 degrees (deg), which is a second delayer (320), and is converted from P-polarized to Right-Handed Circular Polarization (RHCP), and then passes through a lenticular lens (310). The Right-Handed Circular Polarized (RHCP) signal ray (B) passes through a quarter-wave film having a fast axis in the direction of -45 degrees (deg), which is a first delayer (220), and is converted from Right-Handed Circular Polarization (RHCP) to S-polarized, and the S-polarized signal ray (B) passes through an S-polarizer and is reflected from a windshield (10) and finally goes toward the user's eye box (20).

[0130] Figure 9 shows the polarization state of a signal light beam when the polarizer of the dust cover is an S-polarizer and the display panel of the display module is an S-polarizing panel.

[0131] Referring to FIG. 9, according to an embodiment, the polarizer (210) of the dust cover (200) is an S-polarizer (330, S-Polarizer), and in the case where the display module (300) has an S-polarizing panel (330, S-pol panel), the first delayer (220) and the second delayer (320) may be configured to have fast axes in different directions.

[0132] In this case, depending on the embodiment, both the first delayer (220) and the second delayer (320) may include a Quarter Wave Film (QWF). Additionally, the rotation property of the fast axis of the Quarter Wave Film constituting the first delayer (220) and the second delayer (320) may be configured such that when the first delayer (220) is 45 degrees (deg) with respect to the vertical polarization axis, the second delayer (320) is -45 degrees (deg), and when the first delayer (220) is -45 degrees (deg), the second delayer (320) is 45 degrees (deg). This will be explained in more detail below.

[0133] FIG. 9(a) shows the polarization state of a signal light (B) when the first delay element (220) is a quarter wave film with a fast axis of 45 degrees (deg) and the second delay element (320) is a quarter wave film with a fast axis of -45 degrees (deg). FIG. 9(b) shows the polarization state of a signal light (B) when the first delay element (220) is a quarter wave film with a fast axis of -45 degrees (deg) and the second delay element (320) is a quarter wave film with a fast axis of 45 degrees (deg).

[0134] Referring to FIG. 9(a), an S-polarized signal ray (B) emitted from an S-polarizing panel (330) passes through a glass layer (331) and a quarter-wave film having a fast axis in the direction of -45 degrees (deg), which is a second delayer (320), and is converted from S-polarized to Left-Handed Circular Polarization (LHCP), and then passes through a lenticular lens (310). The Left-Handed Circular Polarized (LHCP) signal ray (B) passes through a quarter-wave film having a fast axis in the direction of 45 degrees (deg), which is a first delayer (220), and is converted from Left-Handed Circular Polarization (LHCP) to S-polarized, and the S-polarized signal ray (B) passes through an S-polarizer and is reflected from a windshield (10) and finally goes toward the user's eye box (20).

[0135] Referring to FIG. 9(b), an S-polarized signal ray (B) emitted from an S-polarizing panel (330) passes through a glass layer (331) and a quarter-wave film having a fast axis in the 45-degree (deg) direction, which is a second delayer (320), and is converted from S-polarized to Right-Handed Circular Polarization (RHCP), and then passes through a lenticular lens (310). The Right-Handed Circular Polarized (RHCP) signal ray (B) passes through a quarter-wave film having a fast axis in the -45-degree (deg) direction, which is a first delayer (220), and is converted from Right-Handed Circular Polarization (RHCP) to S-polarized, and the S-polarized signal ray (B) passes through an S-polarizer and is reflected from the windshield (10) and finally goes toward the user's eye box (20).

[0136] FIG. 10 shows a head-up display device in which the polarizer of the dust cover according to one embodiment of the present invention is a P-polarizer.

[0137] In FIG. 10, the polarizer (210) may be, for example, a P-polarizer.

[0138] In the case where the polarizer (210) of the dust cover (200) is a P-polarizer, a P-polarization reflective coating is additionally formed on the windshield (10) placed on the upper part of the dust cover (200).

[0139] In this configuration, the solar rays (A) pass through the windshield (10) and the P-polarizer of the dust cover (200). During this process, the S-polarized portion of the solar rays (A) is absorbed by the P-polarizer, and only the P-polarized portion passes through the first delayer (220) and is converted into circularly polarized solar rays (A).

[0140] Circularly polarized sunlight (A) is reflected from the surface of the display module (300) and the polarization state is changed to the opposite direction.

[0141] In the opposite direction, the circularly polarized sunlight (A) passes through the first delay device (220) of the dust cover (200) again and is converted into S-polarized sunlight (A). Then, the S-polarized sunlight (A) is absorbed by the P-polarizer of the dust cover (200) and does not go toward the user's eye box (20).

[0142] Next, the configuration of the display module (300) of the head-up display device (100) according to the present embodiment will be described.

[0143] Figure 11 shows the configuration of the display module in the head-up display device of Figure 10.

[0144] Referring to FIG. 11, a display module (300), which is a component of a head-up display device (100) according to the present embodiment, has a display panel (330) and an optical layer (310) that is laminated on the upper surface of the display panel (330) and forms a three-dimensional image, and a second delay device (320) may be disposed between the optical layer (310) and the display panel (330). Here, the optical layer may include, for example, a lenticular lens.

[0145] The signal light (B) is generated from the S-polarized flat panel (330) of the display module (300) and passes through the second delayer (320) and the lenticular lens (310) in sequence. As the signal light (B) passes through the second delayer (320), the S-polarized signal light (B) is converted into a circularly polarized signal light (B), and after passing through the lenticular lens (310), it passes through the first delayer (220) again and is converted from a circularly polarized signal light (B) into a P-polarized signal light (B). As a result, the P-polarized signal light (B) passes smoothly through the P-polarizer and is P-polarized reflected by the P-Polarization Reflective Coating located on the windshield (10) and enters the user's eye box (20).

[0146] Figure 12 shows the polarization state of a signal light beam when the polarizer of the dust cover is a P-polarizer and the display panel of the display module is an S-polarizer panel.

[0147] FIG. 12(a) shows the polarization state of a signal light (B) when the first delayer (220) and the second delayer (320) are quarter wave films and the fast axis of the quarter wave film has a direction of 45 degrees (deg) with respect to the vertical polarization axis, and FIG. 12(b) shows the polarization state of a signal light (B) when the first delayer (220) and the second delayer (320) are quarter wave films and the fast axis of the quarter wave film has a direction of -45 degrees (deg).

[0148] A polarizer (210) of a dust cover (200) according to one embodiment of the present invention may include a P-polarizer.

[0149] Referring to FIG. 12, when the display module (300) has an S-polarizing panel (330, S-pol panel), the first delayer (220) and the second delayer (320) may be configured to have a fast axis in the same direction. According to an embodiment, both the first delayer (220) and the second delayer (320) may include a quarter wave film (QWF). In this case, the rotation property of the fast axis of the quarter wave film constituting the first delayer (220) and the second delayer (320) may be configured to have 45 degrees (deg) with respect to the vertical polarization axis (see FIG. 12(a)) or to have -45 degrees (deg) with respect to the vertical polarization axis (see FIG. 12(b)).

[0150] Referring to FIG. 12(a), an S-polarized signal ray (B) emitted from an S-polarized panel (330) passes through a glass layer (331) and a quarter-wave film having a fast axis in the 45-degree (deg) direction, which is a second delayer (320), and is converted from S-polarized to Right-Handed Circular Polarization (RHCP), and then passes through a lenticular lens (310). The Right-Handed Circular Polarized (RHCP) signal ray (B) passes through a quarter-wave film having a fast axis in the 45-degree (deg) direction, which is a first delayer (220), and is converted from Right-Handed Circular Polarization (RHCP) to P-polarization, and the P-polarized signal ray (B) passes through a P-polarizer, is reflected from the windshield (10), and finally heads toward the user's eye box (20).

[0151] Referring to FIG. 12(b), an S-polarized signal ray (B) emitted from an S-polarized panel (330) passes through a glass layer (331) and a quarter-wave film having a fast axis in the direction of -45 degrees (deg), which is a second delayer (320), and is converted from S-polarized to Left-Handed Circular Polarization (LHCP), and then passes through a lenticular lens (310). The LHCP signal ray (B) passes through a quarter-wave film having a fast axis in the direction of -45 degrees (deg), which is a first delayer (220), and is converted from LHCP to P-polarized, and the P-polarized signal ray (B) passes through a P-polarizer and is reflected from the windshield (10) and finally goes toward the user's eye box (20).

[0152] Figure 13 shows the polarization state of a signal light beam when the polarizer of the dust cover is a P-polarizer and the display panel of the display module is a P-polarized panel.

[0153] Referring to FIG. 13, in accordance with the embodiment, the polarizer (210) of the dust cover (200) is a P-polarizer, and in the case where the display module (300) has a P-polarizing panel (330, P-pol panel), the first delayer (220) and the second delayer (320) may be configured to have fast axes in different directions.

[0154] In this case, depending on the embodiment, both the first delayer (220) and the second delayer (320) may include a Quarter Wave Film (QWF). Additionally, the rotation property of the fast axis of the Quarter Wave Film constituting the first delayer (220) and the second delayer (320) may be configured such that when the first delayer (220) is 45 degrees (deg) with respect to the vertical polarization axis, the second delayer (320) is -45 degrees (deg), and when the first delayer (220) is -45 degrees (deg), the second delayer (320) is 45 degrees (deg). This will be explained in more detail below.

[0155] FIG. 13(a) shows the polarization state of a signal light (B) when the first delay element (220) is a quarter wave film with a fast axis of 45 degrees (deg) and the second delay element (320) is a quarter wave film with a fast axis of -45 degrees (deg). FIG. 13(b) shows the polarization state of a signal light (B) when the first delay element (220) is a quarter wave film with a fast axis of -45 degrees (deg) and the second delay element (320) is a quarter wave film with a fast axis of 45 degrees (deg).

[0156] Referring to FIG. 13(a), a P-polarized signal ray (B) emitted from a P-polarized panel (330) passes through a glass layer (331) and a quarter-wave film having a fast axis in the direction of -45 degrees (deg), which is a second delayer (320), and is converted from P-polarized to Right-Handed Circular Polarization (RHCP), and then passes through a lenticular lens (310). The Right-Handed Circular Polarized (RHCP) signal ray (B) passes through a quarter-wave film having a fast axis in the direction of 45 degrees (deg), which is a first delayer (220), and is converted from Right-Handed Circular Polarization (RHCP) to P-polarized, and the P-polarized signal ray (B) passes through a P-polarizer and is reflected from a windshield (10) and finally goes toward the user's eye box (20).

[0157] Referring to FIG. 13(b), a P-polarized signal light (B) emitted from a P-polarizing panel (330) passes through a glass layer (331) and a quarter-wave film having a fast axis in the 45-degree (deg) direction, which is a second delayer (320), and is converted from P-polarized to Left-Handed Circular Polarization (LHCP), and then passes through a lenticular lens (310). The Left-Handed Circular Polarized (LHCP) signal light (B) passes through a quarter-wave film having a fast axis in the -45-degree (deg) direction, which is a first delayer (220), and is converted from Left-Handed Circular Polarization (LHCP) to P-polarized, and after passing through a P-polarizer, the P-polarized signal light (B) is reflected from the windshield (10) and finally goes toward the user's eye box (20).

[0158] Figure 14 shows the change in incident light polarization of an ideal mirror reflection and the Fresnel reflectance for each polarization according to the angle of incidence of the incident light.

[0159] Figure 14(a) shows the change in the polarization state of light when light passing through a linear polarizer and a quarter waveplate is reflected from an ideal mirror at an angle of incidence of 0 degrees.

[0160] Figure 14(b) shows the Fresnel reflectance for each polarization according to the angle of incidence of the incident light.

[0161] In FIG. 14(b), the horizontal axis represents the Angle of Incidence (AOI), which ranges from 0 to 90 degrees. The vertical axis represents the Reflectance, which ranges from 0% to 100%.

[0162] Rs represents the S-polarized light, Rp represents the P-polarized light, and R represents the average value of the two.

[0163] Looking at the graph in Fig. 14(b), the surface of the object acts like a fold mirror when the angle of incidence (AOI) is from 0 to 20 degrees, but the surface of the object does not act like a fold mirror when the angle of incidence is from 20 to 40 degrees. In other words, as the angle of incidence increases, the difference in Fresnel reflectance increases according to the polarization characteristics.

[0164] Figure 15 shows the change in polarization characteristics of the incident and emitted light for the case of fold mirror reflection and Fresnel reflection, respectively.

[0165] Figure 15(a) shows the case of fold mirror reflection, and Figure 15(b) shows the case of Fresnel reflection.

[0166] In the case of Fig. 15(a), the circular polarization shape is maintained, but in the case of Fig. 15(b), the circular polarization shape appears more distorted. As can be seen from Fig. 14(b), the case of Fig. 15(a) corresponds to the case where the angle of incidence is 20 degrees or less.

[0167] Referring to Fig. 14, ideally, when a reflection occurs at an angle of incidence of nearly 0 degrees (deg) on ​​a mirror-like surface, a quarter wave film (QWF) with a fast axis rotated to 45 degrees can be used as a delayer.

[0168] However, in reality, reflection from the surface has Fresnel properties and occurs at any angle of incidence other than 0 degrees. That is, when the angle of incidence is not 0 degrees, especially when it is 20 degrees or more, the Fresnel-reflected light does not have a shape that is exactly opposite to the circular polarization shape of the incident light (see Fig. 15(b)).

[0169] FIG. 16 illustrates a method for controlling the characteristics of a delayer according to an embodiment of the present invention. That is, it illustrates a method for controlling the characteristics of a first delayer (220) and a second delayer (320). FIG. 16(a) is a flowchart illustrating the method for controlling the characteristics of a delayer. FIG. 16(b) is a diagram explaining the delay characteristics and rotation characteristics of a delayer. Referring to FIG. 16(b), the retardation property indicates how much the slow axis lags behind the fast axis after the light ray passes through the delayer, and the rotation property indicates how much the fast axis rotates with respect to the Y-axis after the light ray passes through the delayer.

[0170] A method for adjusting the characteristics of a first delayer (220) and a second delayer (320) according to one embodiment of the present invention may be configured to include, as shown in FIG. 16(a), a first step (S100) of selecting a target polarization and installing a polarizer (210); a second step (S110) of adjusting the delay characteristics and rotation characteristics of the first delayer to suppress reflected sunlight (A); and a third step (S120) of adjusting the delay characteristics and rotation characteristics of the lower delayer to transmit a signal light (B) to an eye box (20).

[0171] In the first step (S100), the polarizer (210) of the dust cover (200) can be selected from an S-polarizer or a P-polarizer.

[0172] In the second step (S110), the rotation property and retardation property of the first delayer (220) can be adjusted in correspondence with the polarizer (210) and the selected display module (300) in the first step (S100).

[0173] In the third step (S120), the rotation property and retardation property of the second delayer (320) can be adjusted in correspondence with the first delayer (220) adjusted in the second step (S110). Additionally, to perform the third step (S120), the display module (300) may be selected from an S-polarizing panel (330, S-pol panel) or a P-polarizing panel (330, P-pol panel). For reference, the panel (330) of the display module (300) does not need to be considered in the second step (S110).

[0174] The adjustment of the first delay device (220) in the aforementioned second stage (S110) and the adjustment of the second delay device (320) in the third stage (S120) can each be performed through simulation.

[0175] In the second step (S110), the adjustment of the first delayer (220) is to find the minimum value (Min value) for the first delayer (220), and in the third step (S120), the adjustment of the second delayer (320) is to find the maximum value (Max value) for the second delayer (320).

[0176] Below, the case where the polarizer (210) of the dust cover (200) is selected as an S-polarizer is described.

[0177] First, in the first step (S100), the polarizer (210) of the dust cover (200) is selected as an S-polarizer, and the S-polarizer is mounted on the dust cover (200).

[0178] Considering that there is a 3D image forming layer, such as a lenticular lens (310), on the surface of the actual display panel (330), the retardation property and rotation property of the first delayer (220) must be found to minimize the leakage of reflected sunlight (Reflected Sunlight Leakage) that passes through the S-polarizer on the path where sunlight (A) is reflected back from the display panel (330). These two properties (Retardation Property, Rotation Property) in the second step (S110) can be found through simulation, etc., depending on the embodiment (described later in FIG. 17).

[0179] At the same time, in the third step (S120), the retardation property and rotation property of the second delayer (320) must be determined so that all signal rays (B) reaching the eyebox (20) from the display module (300) can smoothly pass through the S-polarizer.

[0180] These two properties (Retardation Property, Rotation Property) in the third step (S120) can be found through simulation, etc., depending on the embodiment (described later in FIG. 18).

[0181] In order to find the delay characteristics and rotation characteristics of the second delayer (320), a linear polarized light ray coming from the display panel (330) (this ray is a standard ray) and a delayer in the 3D image forming layer must be implemented.

[0182] The principle of the third step (S120) is explained as follows. A linearly polarized light ray is emitted from the display panel (330). This linearly polarized light ray passes through the second delayer (320) of the 3D image forming layer and is converted into a circularly polarized light ray. This circularly polarized light ray passes through the first delayer (220) of the dust cover (200) and is converted into an S-polarized light ray. This S-polarized light ray passes through the S-polarizer of the dust cover (200).

[0183] Subsequently, the S-polarized light beam is efficiently reflected by Fresnel reflection from the windshield (10) and enters the eye box (20). Depending on the embodiment, the light beam emitted from the display panel (330) can be both S-polarized and P-polarized.

[0184] When the light beam is S-polarized, a quarter wave film (QWF) having a fast axis rotated in the opposite direction to the first delayer (220) of the dust cover (200) can be used as the second delayer (320).

[0185] When the light beam is P-polarized, a quarter wave film (QWF) having a fast axis rotated in the same direction as the first delayer (220) of the dust cover (200) can be used as the second delayer (320).

[0186] According to the embodiment, when applying to a product, instead of using an ideal quarter wave film (QWF), a second delayer (320) having delay and rotation characteristics that allow maximum light transmission through an S-polarizer can be used by considering the delay and rotation characteristics of the first delayer (220) of the dust cover (200).

[0187] FIG. 17 illustrates a method for finding the optimal delay and rotation characteristics of the first retarder through simulation in the second step of the method for controlling the characteristics of the retarder. FIG. 17(a) shows the conditions for performing the simulation. FIG. 17(b) shows the reflected sunlight leakage (%), which is the result of the simulation. The horizontal axis represents the delay characteristic value (wavelength) of the first retarder (220), and the vertical axis represents the rotation characteristic value (deg) of the first retarder (220). As the blue color becomes darker, the leakage approaches the minimum value (Min value). For reference, the X-axis and Y-axis of FIG. 17(b) are labeled as the top retarder, but this represents the first retarder (220) of the dust cover (200).

[0188] Referring to FIG. 17, a method for finding the characteristics of the first delay device (220) of the second step (S110) according to one embodiment of the present invention by simulation is described.

[0189] First, a polarizer (210) of the dust cover (200) is selected. For example, an S-polarizer may be selected. Then, a P-polarizing panel (330) will be used for the display. In this state, the delay characteristics and rotation characteristics of the first delayer (220) are varied. The initial state of the first delayer (220) may be a quarter-wave film with a fast axis of 45 degrees (deg) relative to vertical polarization. Starting from this state, a simulation is performed while varying the delay characteristics and rotation characteristics of the first delayer (220) to visually and quantitatively verify the amount of reflected sunlight leakage (see FIG. 17(b)).

[0190] Referring to FIG. 17(b), the first delay device (220) is located at a point where the delay characteristic value is 0.25λ and the rotation characteristic value is 45 degrees in the initial state. However, as a result of performing simulations while varying the delay characteristic value and rotation characteristic value of the first delay device (220), the amount of reflected sunlight outflow (light quantity) can be found. In the simulation results, the point is 0.32λ and 49 degrees (deg), which is the region where the blue color is most intense. This point can be determined as the characteristic value of the first delay device (220).

[0191] Figure 18 illustrates a method for finding the delay characteristics and rotation characteristics of the second delayer through simulation in the third step of the delayer characteristic control method.

[0192] FIG. 18(a) shows the conditions for performing the simulation. FIG. 18(b) shows the light intensity (%) of the signal light (B, Signal light at eyebox) at the eyebox (20), which is the simulation result. The horizontal axis (X-axis) represents the delay characteristic value (wavelength) of the second delayer (320), and the vertical axis (Y-axis) represents the rotation characteristic value (deg) of the second delayer (320). As the yellow color becomes darker, the light intensity approaches the maximum value. For reference, the X-axis and Y-axis in FIG. 18(b) are labeled as bottom retarder, but this represents the second delayer (320) of the display module (300).

[0193] Referring to FIG. 18, a method for finding the characteristics of the second delay device (320) of the third step (S120) according to one embodiment of the present invention by simulation is described.

[0194] In the second step (S110), the characteristic value of the first delayer (220) was first found and determined. The characteristic value of the first delayer (220) determined in the above example is 0.32λ and 49 degrees (deg). Based on the first delayer (220) having this characteristic value, the delay and rotation characteristics of the second delayer (320) of the display module (300) are varied in various ways under the simulation condition state of the first delayer (220) described above. The initial state of the second delayer (320) may be a quarter-wave film with a fast axis of 45 degrees (deg). Starting from this state, a simulation is performed while varying the delay and rotation characteristics of the second delayer (320) in various ways so that the amount of signal light can be visually and quantitatively verified at the eye box (20) position (see FIG. 18(b)).

[0195] Referring to FIG. 18(b), the second delay device (320) is located at a point where the delay characteristic value (wavelength) is 0.25λ and the rotation characteristic value is 45 degrees (deg) in the initial state. However, as a result of performing a simulation while varying the delay characteristic value and rotation characteristic value of the second delay device (320), the amount of light of the signal light (B) at the eye box (20) can be found. In the simulation results, it is at a point of 0.32λ and 23 degrees (deg), which is the region where the yellow color is most intense. This point can be determined as the characteristic value of the second delay device (320).

[0196] FIG. 19 is a figure showing the effect of reducing solar reflection due to the presence or absence of the first delay device according to the present embodiment. That is, it is a simulation result showing how much solar radiation (A) is reflected when looking at the display from the eye box (20). FIG. 19(a) shows Fresnel-reflected solar radiation (A) from the panel (330) when the dust cover (200) is not used, and FIG. 19(b) shows the reflection of solar radiation (A) when the dust cover (200) with the first delay device (220) optimally adjusted is used. FIG. 19(b) indicates that the solar radiation leakage is less than 1%, which is significantly reduced compared to FIG. 19(a).

[0197] FIG. 20 is a figure showing the signal output result according to the use of the second delay device according to the present embodiment.

[0198] Figure 20 shows the result after warping compensation, so the display appears rectangular. Figure 20 is an image of a signal light (B) when the second delay device (320) uses an optimally adjusted display module (300), and means that a signal light (B) of maximum brightness enters the eye box (20).

[0199] Figure 21 is a figure comparing the respective reflection characteristics of a single-layer lenticular lens and a multi-layer lenticular lens having different refractive indices.

[0200] FIG. 21(a) shows the lenticular lens (310) when composed of a single layer, and FIG. 21(b) shows the lenticular lens when composed of multiple layers.

[0201] The single-layer lenticular lens (310) of FIG. 21(a) has a very large difference in refractive index with the atmosphere, which is 0.49. Therefore, sunlight (A) dispersed in one direction in a linear form is clearly displayed.

[0202] The multi-layer lenticular lens of FIG. 21(b) is composed of double layers using materials with different refractive indices. Depending on the embodiment, an AR coating may be added to the upper surface of the double-layer lenticular lens. In this case, the difference in refractive index of the lenticular lenses (310) is very small, with the upper lenticular lens (310) being 0.05 and the lower lenticular lens (310) being 0.08. As a result, the intensity of the reflected sunlight (A) is weakened. This provides an additional effect of reducing the reflection of sunlight (A).

[0203] The embodiments according to the present invention described above may be implemented in the form of a computer program that can be executed through various components on a computer, and such a computer program may be recorded on a computer-readable medium. In this case, the medium may include a magnetic medium such as a hard disk, a floppy disk, and a magnetic tape, an optical recording medium such as a CD-ROM and a DVD, a magneto-optical medium such as a floptical disk, and a hardware device specifically configured to store and execute program instructions, such as a ROM, RAM, or flash memory.

[0204] Meanwhile, the above-mentioned computer program may be one specifically designed and configured for the present invention, or one known and available to those skilled in the art of computer software. Examples of computer programs may include machine code, such as that generated by a compiler, as well as high-level language code that can be executed by a computer using an interpreter, etc.

[0205] In the specification of the present invention (particularly in the claims), the use of the term "above" and similar descriptive terms may be in both singular and plural. Furthermore, where a range is described in the present invention, it is to include an invention to which individual values ​​belonging to said range are applied (unless otherwise stated), and this is equivalent to describing each individual value constituting said range in the detailed description of the invention.

[0206] Unless explicitly stated or contrary to the order of the steps constituting the method according to the present invention, said steps may be performed in a suitable order. The present invention is not necessarily limited by the order in which said steps are described. The use of all examples or exemplary terms (e.g., etc.) in the present invention is merely for the purpose of describing the present invention in detail, and the scope of the present invention is not limited by said examples or exemplary terms unless limited by the claims. Furthermore, those skilled in the art will understand that various modifications, combinations, and changes may be made according to design conditions and factors within the scope of the claims or equivalents to which they are added.

[0207] Accordingly, the scope of the present invention should not be limited to the embodiments described above, and all scopes equivalent to or equivalently modified from the claims set forth below, as well as the claims set forth below, shall be considered to fall within the scope of the concept of the present invention.

[0208] (Explanation of symbols)

[0209] 10: Windshield

[0210] 11: P-polarized reflective coating

[0211] 20: iBox

[0212] 100: Head-up display device

[0213] 200: Dust cover

[0214] 300: Display module

[0215] A: Sunlight

[0216] B: Signal beam

[0217] 210: Polarizer

[0218] 220: Delay period (1st delay period)

[0219] 310: Lenticular lens

[0220] 320: Second delay device

[0221] 330: Display panel

[0222] 331: Glass layer

[0223] S100: Polarizer installation step

[0224] S110: First delay control step

[0225] S120: Second delay control step

Claims

1. A dust cover that reduces sunlight directed toward the user's eye box by controlling and manipulating the polarization state of sunlight; and A display module that controls and manipulates the polarization state of a signal light to allow the signal light to smoothly pass through the dust cover and reach the eye box; A head-up display device including 2. In Paragraph 1, A head-up display device characterized in that the dust cover has a concave shape to prevent sunlight reflected from its surface from being transmitted to the user's eye box.

3. In Paragraph 1, A head-up display device characterized in that the dust cover has a polarizer and a first retarder, and the display module has a second retarder.

4. In Paragraph 3, A head-up display device characterized by having the first delay element disposed on the lower surface of the polarizer of the dust cover.

5. In Paragraph 3, A head-up display device characterized in that the display module comprises a display panel and an optical layer laminated on the upper surface of the display panel and forming a three-dimensional image, and the second delayer is disposed between the optical layer and the display panel.

6. In Paragraph 5, A head-up display device characterized in that the optical layer comprises a first layer and a second layer having different refractive indices.

7. In Paragraph 6, A head-up display device characterized by having an anti-reflection coating formed on the surface of the optical layer.

8. In Paragraph 3, A head-up display device characterized by the first delay device and the second delay device converting a linearly polarized light into a circularly polarized light or vice versa.

9. In Paragraph 3, A head-up display device characterized by the above-mentioned polarizer including an S-polarizer.

10. In Paragraph 9, A head-up display device characterized in that, when the above-described display module has a P-polarizing panel, the first delay and the second delay have a fast axis in the same direction.

11. In Paragraph 10, A head-up display device characterized in that both the first delay device and the second delay device include a Quarter Wave Film (QWF).

12. In Paragraph 11, A head-up display device characterized in that the rotation property of the fast axis of the quarter wave film is 45 degrees (deg) or -45 degrees (deg) with respect to the vertical polarization axis.

13. In Paragraph 9, A head-up display device characterized in that, when the display module has an S-polarizing panel, the first delay and the second delay have fast axes in different directions.

14. In Paragraph 13, A head-up display device characterized in that both the first delay device and the second delay device include a Quarter Wave Film (QWF).

15. In Paragraph 14, A head-up display device characterized in that the rotation property of the fast axis of the quarter wave film is 45 degrees and -45 degrees, or -45 degrees and 45 degrees, respectively, with respect to the vertical polarization axis.

16. In Paragraph 3, A head-up display device characterized by the above-mentioned polarizer including a P-polarizer.

17. In Paragraph 16, A head-up display device characterized by having a P-Polarization Reflective Coating formed on a windshield positioned on the upper part of the dust cover.

18. In Paragraph 17, A head-up display device characterized in that, when the above-described display module has an S-polarizing panel, the first delay and the second delay have a fast axis in the same direction.

19. In Paragraph 18, A head-up display device characterized in that both the first delay device and the second delay device include a Quarter Wave Film (QWF).

20. In Paragraph 19, A head-up display device characterized in that the rotation property of the fast axis of the quarter wave film is 45 degrees (deg) or -45 degrees (deg) with respect to the vertical polarization axis.

21. In Paragraph 17, A head-up display device characterized in that, when the display module has a P-polarizing panel, the first delay and the second delay have fast axes in different directions.

22. In Paragraph 21, A head-up display device characterized in that both the first delay device and the second delay device include a Quarter Wave Film (QWF).

23. In Paragraph 22, A head-up display device characterized in that the rotation property of the fast axis of the quarter wave film is 45 degrees and -45 degrees, or -45 degrees and 45 degrees, respectively, with respect to the vertical polarization axis.

24. In Paragraph 3, A head-up display device characterized in that the polarizer is selected from an S-polarizer or a P-polarizer, and the display module is selected from an S-polarizing panel or a P-polarizing panel.

25. In Paragraph 24, A head-up display device characterized by adjusting the rotation property and retardation property of the first delay device in correspondence with the selected polarizer and the selected display module.

26. In Paragraph 25, A head-up display device characterized by adjusting the rotation property and retardation property of the second delay device in correspondence with the first delay device adjusted above.

27. In Paragraph 26, A head-up display device characterized in that the adjustment of the first delay device and the adjustment of the second delay device are each performed through simulation.

28. In Paragraph 26, The adjustment of the first delay device is to find the minimum value (Min value) for the first delay device, and A head-up display device characterized by the adjustment of the second delay device by finding the maximum value for the second delay device.

29. A step of absorbing sunlight in which sunlight passes through a dust cover, changes its polarization state at least once, is reflected by Fresnel, moves back to the dust cover, changes its polarization state at least once, and is then absorbed by the dust cover; A signal light emission step in which a signal light emitted from a display panel passes through the dust cover and changes its polarization state at least once while reaching the user's eye box; A display method for reducing solar reflection including 30. In Paragraph 29, A display method for reducing solar reflection, characterized in that the absorption step converts the polarization state four times and the emission step converts the polarization state two times.

31. In Paragraph 29, A display method for reducing solar reflection, characterized in that the polarization state of the absorption step is such that the solar rays are first linearly polarized, first circularly polarized, second circularly polarized, and second linearly polarized.

32. In Section 31, A display method for reducing solar reflection, characterized in that the first linear polarization and the second linear polarization are each P-polarization and S-polarization, or S-polarization and P-polarization.

33. In Section 31, A display method for reducing solar reflection, characterized in that the first circular polarization and the second circular polarization are respectively left-handed circular polarization (LHCP) and right-handed circular polarization (RHCP), or right-handed circular polarization and left-handed circular polarization.

34. In Paragraph 29, A display method for reducing solar reflection, characterized in that the polarization state of the emission step is such that the signal light is converted from a first linear polarization to circular polarization and then converted again to a second linear polarization.

35. In Paragraph 34, A display method for reducing solar reflection, characterized in that when a first delay device converting from a first linear polarization to circular polarization and a second delay device converting from circular polarization to a second linear polarization are in the same direction, the first linear polarization and the second linear polarization are P-polarization and S-polarization, or S-polarization and P-polarization, respectively.

36. In Paragraph 34, A display method for reducing solar reflection, characterized in that when a first delayer converting from a first linear polarization to circular polarization and a second delayer converting from circular polarization to a second linear polarization are in different directions, the first linear polarization and the second linear polarization are both P-polarization or both S-polarization.

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