JP6697435B2 - Window glass for vehicles and in-vehicle system - Google Patents

Description

  The present invention relates to a window glass for a vehicle and an in-vehicle system.

  In recent years, an in-vehicle system has been proposed in which a camera for photographing the situation outside the vehicle is installed inside the vehicle. This in-vehicle system recognizes oncoming vehicles, vehicles in front, pedestrians, traffic signs, lane boundaries, etc. by analyzing captured images of the subject acquired by the camera, and informs the driver of various dangers. Can provide driving assistance.

  However, a shielding layer for shielding the view from the outside of the vehicle may be provided on the peripheral portion of the glass plate such as the windshield of the automobile. In addition, the camera of this vehicle-mounted system is often installed at a position where the shielding layer is included in the shooting range of the camera, such as in the vicinity of the support portion of the rearview mirror. Therefore, there is a possibility that this shielding layer may interfere with the shooting by the camera.

  Therefore, conventionally, it has been proposed to provide a transmission window in a part of the shielding layer. For example, in Patent Document 1, a part of the shielding layer (shade part) provided on the synthetic resin film for laminated glass is replaced with a material having a high visible light transmittance, so that a part of the shade part transmits visible light. A region having a high rate (translucent portion) is formed. As a result, the camera installed inside the vehicle can photograph the situation outside the vehicle without being obstructed by the shielding layer.

JP, 2006-096331, A

  However, the inventors of the present invention have found that when the glass plate for a vehicle is arranged in an inclined posture, the following problems occur in addition to the obstruction of photographing by the camera due to the shielding layer. .. That is, as illustrated in FIG. 24, the imaging device (camera) 900 installed in the vehicle receives the main light flux 902 that has passed through the glass plate 901 without being reflected in the glass plate 901, and thus the vehicle exterior. To capture the situation. At this time, when the glass plate 901 is arranged in an inclined posture with respect to the vertical direction, as illustrated in FIG. 24, the sub-light flux 903 emitted from the same light source as the main light flux 902 is reflected inside the glass plate 901. Then, the glass plate 901 can be shifted upward so as to substantially overlap the optical path of the main light beam 902. That is, the sub-light flux 903 may be received by the image capturing apparatus 900 by repeating the reflection within the glass plate 901 and finally following the optical path of the main light flux 902 at a slightly different angle. Then, on the imaging surface (CCD or the like) of the image capturing apparatus 900, the sub-light flux 903 emitted from the same position as the main light flux 902 forms an image at a position deviated from the main light flux 902. The present inventors have found a problem that a double image may occur.

  The present invention, in one aspect, has been made in view of such circumstances, and an object thereof is to prevent a double image from being generated in a captured image captured through a glass plate arranged in a tilted posture. To provide the technology to do so.

  The present invention adopts the following configurations in order to solve the problems described above.

  That is, a window glass according to one aspect of the present invention is a window glass used in a vehicle in which an image capturing device can be arranged, and a glass plate disposed in an inclined posture, and a glass plate that passes through the glass plate and is attached to the image capturing device. A sub-beam that is a sub-beam emitted from the same place as the main beam that enters, and that blocks the progress of the sub-beam that may enter the vicinity of the optical path of the main beam by being reflected within the glass plate. And a blocking section which is arranged at a position on the optical path of the glass plate and which does not block the optical path of the main light flux.

  With the window glass according to this configuration, the image capturing device installed in the vehicle captures an image of the outside of the vehicle through the glass plate that is arranged in an inclined posture. Specifically, the image capturing device captures the situation outside the vehicle by receiving the main light flux that has passed through the glass plate. At this time, since the glass plate is arranged in an inclined posture, the sub-light flux emitted from the same place as the main light flux can enter the optical path of the main light flux by being reflected in the glass plate.

  Therefore, in the window glass according to this configuration, the blocking unit that blocks the progress of the sub-beam is arranged at a position on the optical path of the glass plate of the sub-beam that does not block the optical path of the main beam. Therefore, it is possible to prevent the sub-light flux from approaching the optical path of the main light flux and approaching the main light flux without blocking the progress of the main light flux by the blocking unit. Therefore, according to the configuration, it is possible to prevent a double image from being generated in a captured image captured through the glass plate arranged in the inclined posture. It should be noted that the vicinity of the optical path of the main light beam into which the sub-light beam can enter refers to the optical path of the main light beam as a reference, and when the sub-light beam enters, it passes through the entrance pupil in the optical system of the photographing apparatus to generate the double image. Indicates the range to do.

  Further, as another mode of the window glass according to the above configuration, the blocking portion is disposed on the vehicle outer side than the vehicle inner surface of the glass plate, and the transmission preventing member and the glass plate which prevent transmission of the sub-light flux. It may be configured on at least one of an antireflection member that is disposed on the inner surface of the vehicle and that prevents reflection of the sub-light flux. According to this configuration, it is possible to prevent a double image from occurring in a captured image captured through the glass plate arranged in the inclined posture with a simple configuration.

  Note that the transmission preventing member is not particularly limited as long as it is a member that prevents or reduces light rays from passing through the glass plate. In addition, for example, as a method of forming the permeation-preventing member, a method of attaching an opaque ink, a paint, a metal film or the like to the surface of the glass plate by means of printing, painting, coating, sand sand (sand blast), etching, etc. Examples of the method include a method in which minute irregularities are provided in the relevant portion of the glass plate by a means to form a light scattering surface, and a method in which only the vicinity of the surface of the relevant portion is chemically modified to make it opaque.

  Further, the antireflection member is not particularly limited as long as it is a member that prevents or reduces reflection of light rays. Further, for example, as a method of forming an antireflection member, a method of attaching an ink, a paint, a metal film layer or the like having a low reflectance to the surface of a glass plate by a means such as printing, painting or coating, or a light absorbing material is used. A method of adhering the constituted plate material to the surface of the glass plate, sand sand, a method of forming minute unevenness on the part of the glass plate by a means such as etching to form a light-scattering surface, chemically only near the surface of the part Examples thereof include a method of modifying to reduce the reflectance and a method of applying an antireflection coating on the surface of the glass plate.

  Further, the vehicle exterior side of the glass plate on the vehicle interior side is, for example, the vehicle exterior surface of the glass plate. Further, when the glass plate is made of laminated glass that is bonded to each other through an interlayer film by the outer glass plate and the inner glass plate, the outer side of the surface of the glass plate on the vehicle inner side is, for example, the outer glass. These are the outer surface of the plate, the inner surface of the outer glass plate, and the outer surface of the inner glass plate.

  Further, as another mode of the window glass according to the above configuration, the blocking unit in a direction in which the sub-beam can shift when it is assumed that the sub-beam enters the glass plate and is reflected in the glass plate. May have a width equal to or longer than a length L satisfying the expression (1), and the cutoff portion transmits the main light flux in the range of the length L from the cutoff portion in a direction in which the sub-light flux may shift. May be arranged to do so.

In addition, T shows the thickness of the said glass plate. θ indicates an incident angle of a light ray traveling in the horizontal direction with respect to the glass plate. n indicates the refractive index of the glass plate.

  Assuming a situation in which the sub-beam enters the optical path of the main beam without providing the blocking section, the amount by which the sub-beam shifts toward the main beam due to reflection in the glass plate arranged in an inclined posture (deviation amount ) Is defined by the length L of the above formula (1). That is, the blocking unit arranged on the glass plate blocks the progress of the sub-beam that can enter the position away from the blocking unit by the length L in the direction in which the sub-beam can shift. In other words, the range in which the sub-beam can be prevented from entering the optical path of the main beam is between the end of the block and the position separated from the block by the length L in the direction in which the sub-beam can shift. It is the range between. However, if the width of the blocking portion in the direction in which the sub-beams can shift within the glass plate is less than the length L, it is not possible to prevent the sub-beams from entering the entire range.

  Therefore, in this configuration, the width of the blocking portion in the direction in which the sub-beam may shift within the glass plate is formed to be the length L or more. Then, the blocking portion is arranged so that the main light flux passes through the range of the length L from the blocking portion in the direction in which the sub-light flux reflected in the glass plate may shift. As a result, it is possible to effectively suppress the occurrence of a double image due to the sub-light flux entering the optical path of the main light flux.

  In addition, it is preferable that the upper limit value of the width of the blocking portion is set to a length that does not overlap the driver's visual field range. Here, the visual field range in which the driver who drives the vehicle checks the traffic conditions when driving is a range that the driver in the driver's seat pays attention to when driving, and can be appropriately set according to the embodiment. Is. For example, the test area A defined in JIS R 3212 (1998, “Test method for safety glass for automobiles”) may be adopted as the visual field range.

Further, as another mode of the window glass according to the above configuration, the blocking unit in a direction in which the sub-beam can shift when it is assumed that the sub-beam enters the glass plate and is reflected in the glass plate. _{May be} greater than or equal to the length L ₀ satisfying the expression (2), and the cutoff portion may move the sub-light flux in a direction from the cutoff portion to the main light flux in the range of the length L _0. May be arranged to be transparent.

In addition, T shows the thickness of the said glass plate. n indicates the refractive index of the glass plate.

The length L ₀ of the expression (2) is a value of the length L when the incident angle θ of the expression (1) is set to 10 degrees. When the incident angle θ of the light ray traveling in the horizontal direction with respect to the glass plate is less than 10 degrees, that is, when the surface of the glass plate is close to vertical, the shift amount of the sub-light flux becomes extremely small, and the doubled light appears on the captured image. Images are less likely to occur. Therefore, in such a case, it is not necessary to take measures against the double image. On the other hand, according to the configuration, when the incident angle θ of the light ray traveling in the horizontal direction with respect to the glass plate is 10 degrees or more, that is, the glass plate is tilted at an inclination angle where the demand for countermeasures against double images increases. When installed, the occurrence of double images can be effectively suppressed.

  In addition, as another mode of the window glass according to the above configuration, a shielding layer that is provided on the glass plate and shields a field of view from the outside of the vehicle, and the main light flux so that the image capturing device can capture an image of a state outside the vehicle. May further include a shielding layer having an image-capturing window that allows light to pass therethrough, and the shielding unit may be configured by a part of the shielding layer. According to this configuration, since it is not necessary to separately form the blocking unit, it is possible to prevent a double image from being generated in a captured image with a simple configuration.

Further, as another mode of the window glass having the above configuration, the area of the photographing window may be 3000 mm ² or less. With this configuration, the size of the shooting window can be made relatively small to prevent extra light from entering the shooting device. Therefore, according to the said structure, the contrast of the picked-up image imaged through the glass plate can be improved. In addition, since it becomes difficult to see the photographing device and the like when viewed from the outside, the appearance of the automobile can be improved.

  Further, as another mode of the window glass according to the above configuration, the blocking unit in a direction in which the sub-beam can shift when it is assumed that the sub-beam enters the glass plate and is reflected in the glass plate. May have a width equal to or longer than a length L satisfying the above formula (1), and the cutoff portion is arranged such that the main light flux has a range of the length L from the cutoff portion in a direction in which the sub-light flux can shift. It may be arranged to be transparent. Further, the width of the photographing window in the direction in which the sub-beam may shift may be formed to be the length L or more. According to this configuration, it is possible to effectively prevent the double image from being generated in the captured image, and to install a shooting window capable of capturing the situation outside the vehicle within the range in which the double image is suppressed. become.

  Further, as another mode of the window glass according to the above configuration, the shooting window in a direction in which the sub-beam can shift when it is assumed that the sub-beam enters the glass plate and is reflected in the glass plate. May be formed so as to satisfy the equation (3).

It should be noted that R represents the diameter of the entrance pupil in the optical system of the photographing device. H indicates the width of the photographing window in the direction in which the sub-light flux can shift. θ represents the incident angle of the light ray traveling in the horizontal direction with respect to the glass plate.

  The entrance pupil is an image when the aperture stop of the optical system that constitutes the image capturing apparatus is viewed from the subject side, and corresponds to the “entrance” of light used in the optical system. Therefore, if the width H of the photographing window and the diameter R of the entrance pupil do not satisfy the above expression (3), the range through which the light ray required by the photographing apparatus passes is no matter how the photographing apparatus is arranged. Therefore, at least a part of the light rays will be blocked by the shielding layer. On the contrary, if the width H of the photographing window and the diameter R of the entrance pupil satisfy the above formula (3), the size of the photographing window sufficient for photographing is secured, and the range through which light rays required by the photographing device pass. Can be configured so that the shielding layer does not block. Therefore, according to the said structure, the size which concerns on the minimum of a photography window can be determined, and by this, the design of a photography window becomes easy. In the case of a camera lens having a focal length f and an aperture ratio F, the diameter R of the entrance pupil is (f / F).

  Further, as another form of the window glass according to the above configuration, the window glass is used in a vehicle in which a stereo camera having a plurality of image capturing devices separated from each other for acquiring a plurality of images with parallax can be arranged. May be. The parallax generated between the plurality of captured images acquired by the stereo camera can be used to measure the distance between the vehicle and the subject. However, when a double image occurs in a captured image, an error occurs in the value of the parallax, which may reduce the accuracy of the measurement. On the other hand, according to the configuration, it is possible to prevent a double image from being generated in the captured image, and thus it is possible to prevent the accuracy of distance measurement by the stereo camera from decreasing. The present technology that suppresses the generation of double images by the blocking unit that blocks the sub-light flux is more effective in situations in which the accuracy of the captured image is required, such as in the case of performing distance measurement with such a stereo camera.

  An on-vehicle system according to one aspect of the present invention is an on-vehicle system for mounting on a vehicle including the window glass according to the above-described embodiment, and is obtained by an image capturing device that captures a situation outside the vehicle, and the image capturing device. An image processing device for processing an image is provided, and an optical system of the photographing device is configured such that an entrance pupil is closer to the subject than the optical component. According to this configuration, the entrance pupil of the image capturing apparatus exists on the subject side of the optical component, and thus can be arranged on or near the glass plate. Therefore, the area on the glass plate of the incident light entering the photographing camera can be reduced. Further, when the shielding layer having the photographing window is formed on the glass plate, the size of the photographing window can be reduced. In addition, this makes it possible to make it less susceptible to defects such as stress distortion in the imaging window portion.

  Further, as another mode of the vehicle-mounted system according to the above configuration, in the image capturing apparatus, an optical distance between an entrance pupil in an optical system of the image capturing apparatus and an image capturing window of the window glass in an optical axis direction of the image capturing apparatus. You may arrange | position so that it may become the range within 10 mm. Here, the optical distance means the optical path length converted into the thickness of the air layer having a refractive index of 1. The present inventors arrange the photographing device such that the optical distance between the entrance pupil of the lens forming the photographing device and the photographing window of the window glass is within 10 mm in the front-back direction in the optical axis direction of the photographing device. Then, it was found that the deformation amount due to the distortion of the image photographed through the photographing window does not easily fluctuate. Therefore, according to the configuration, it is possible to prevent the distortion amount of the image captured through the imaging window from largely changing due to the manufacturing error of the glass plate, and to correct the captured image without considering the individual difference. Can be uniformly set.

  Further, an in-vehicle system according to one aspect of the present invention is an in-vehicle system to be installed in a vehicle including the window glass according to the above-described embodiment, and includes a plurality of spaced apart images so that a plurality of images with parallax can be acquired. A stereo camera having a photographing device, and an image processing device for analyzing a plurality of images acquired by the stereo camera to calculate the position of a subject in the photographing range of the stereo camera are provided. According to the configuration, it is possible to prevent the double image from being generated in the captured image, thereby preventing the accuracy of the distance measurement by the stereo camera from decreasing.

  According to the present invention, it is possible to prevent a double image from occurring in a captured image captured through a glass plate arranged in a tilted posture.

FIG. 1 is a plan view illustrating a window glass according to an embodiment. FIG. 2 is a cross-sectional view illustrating the window glass according to the embodiment. FIG. 3A illustrates the behavior of the main light flux and the sub-light flux in the window glass according to the embodiment. FIG. 3B illustrates the behavior of the main light flux and the sub-light flux when the blocking unit according to the embodiment is not provided. FIG. 4 illustrates the relationship between the photographing window of the window glass and the entrance pupil of the photographing device according to the embodiment. FIG. 5 illustrates an imaging device according to the embodiment. FIG. 6 illustrates an imaging device in which the entrance pupil is inside the lens system. FIG. 7 illustrates a vehicle-mounted system according to the embodiment. FIG. 8 illustrates the manufacturing process of the window glass according to the embodiment. FIG. 9 is a sectional view illustrating a window glass according to another embodiment. FIG. 10 is a cross-sectional view illustrating a window glass according to another embodiment. FIG. 11 is a plan view illustrating a window glass according to another embodiment. FIG. 12 is a cross-sectional view illustrating a window glass according to another embodiment. FIG. 13 is a cross-sectional view illustrating a window glass according to another embodiment. FIG. 14 illustrates an imaging device according to another mode. FIG. 15 illustrates an imaging device according to another mode. FIG. 16 is a plan view illustrating a window glass according to another embodiment. FIG. 17 illustrates an in-vehicle system according to another mode. FIG. 18: shows an example of the manufacturing method of the window glass which concerns on another form. FIG. 19 is a graph showing the distortion of the glass plate. FIG. 20 is a photograph showing the distortion of the glass plate. FIG. 21 exemplifies a scene in which the amount of distortion of an image due to window glass is simulated. FIG. 22A is a graph showing the amount of image distortion when the distance between the window glass and the entrance pupil is changed. FIG. 22B is a graph showing the amount of image distortion when the radius of curvature of the surface on the subject side is changed. FIG. 23A shows a method for measuring reflectance and transmittance. FIG. 23B shows the measurement results of the reflectance of the black ceramic treated surface and the untreated surface. FIG. 23C shows the measurement results of the transmittance of the black ceramic treated surface. FIG. 24 exemplifies a scene in which a double image is generated by a glass plate arranged in a tilted posture. FIG. 25 illustrates a blocking unit according to another mode.

  Hereinafter, an embodiment according to one aspect of the present invention (hereinafter, also referred to as “the present embodiment”) will be described with reference to the drawings. However, the present embodiment described below is merely an example of the present invention in all respects. It goes without saying that various improvements and modifications can be made without departing from the scope of the present invention. That is, in implementing the present invention, a specific configuration according to the embodiment may be appropriately adopted.

§1 Configuration Example First, the window glass 1 according to the present embodiment will be described with reference to FIGS. 1 and 2. FIG. 1 is a plan view schematically illustrating a window glass 1 according to this embodiment. 2 is a cross-sectional view schematically illustrating the window glass 1 according to this embodiment. For convenience of description, the up-down direction of FIG. 1 is referred to as “up-down” and the left-right direction of FIG. 1 is referred to as “left-right”. FIG. 1 illustrates a window glass 1 viewed from the inside of the vehicle. That is, the rear side of the plane of FIG. 1 is the vehicle exterior side, and the front side of the plane of FIG. 1 is the vehicle interior side.

  The window glass 1 according to the present embodiment is a vehicle window glass that is attached to an automobile, and is specifically a windshield of the automobile. As illustrated in FIG. 1, the window glass 1 includes a glass plate 10 having a substantially rectangular shape. Then, as illustrated in FIG. 2, the glass plate 10 is arranged in an inclined posture.

  The glass plate 10 has an inner surface 13 that is an inner surface of the vehicle and an outer surface 14 that is an outer surface of the vehicle. A shielding layer 11 that shields a view from the outside of the vehicle is provided on the inner surface 13 on the inner side of the vehicle, and the imaging device 2 is arranged in the vehicle so that the exterior of the imaging device 2 is shielded. However, the photographing device 2 is a camera for photographing the situation outside the vehicle. Therefore, the shielding layer 11 is formed with a photographing window 113 at a position corresponding to the photographing device 2 so that the photographing device 2 arranged inside the vehicle can photograph the situation outside the vehicle.

  An image processing device 3 is connected to the image capturing device 2, and a captured image acquired by the image capturing device 2 is processed by the image processing device 3. The imaging device 2 and the image processing device 3 constitute an in-vehicle system 5, and the in-vehicle system 5 can provide various information to a passenger according to the processing of the image processing device 3. Hereinafter, each component will be described.

<Glass plate>
First, the glass plate 10 will be described. The glass plate 10 according to the present embodiment is used as a windshield of an automobile and is formed into a shape corresponding to the window frame of the automobile to be attached. Specifically, the glass plate 10 according to the present embodiment has a substantially rectangular shape in a plan view, and in a side view, the inner surface of the vehicle is concave and the outer surface of the glass is convex so that the peripheral edge is It is formed in a curved shape from the portion to the central portion.

  Further, the glass plate 10 is arranged in an inclined posture. Specifically, the glass plate 10 according to the present embodiment is arranged so as to incline from the vehicle outer side to the vehicle inner side with respect to the vertical direction. The angle at which the glass plate 10 is attached to the automobile (hereinafter, also referred to as “tilt angle”) can be set as appropriate according to the embodiment. For example, the mounting angle of the glass plate 10 can be set to 45 degrees or less from the horizontal direction.

  Such a glass plate 10 can have various configurations depending on the embodiment. A known glass plate for automobiles can be used as the glass plate 10. For example, for the glass plate 10, heat ray absorbing glass, general clear glass or green glass, or UV green glass may be used. However, such a glass plate 10 needs to realize a visible light transmittance in accordance with the safety standard of the country in which the automobile is used. For example, the solar absorptance, the visible light transmittance and the like can be adjusted so as to meet the safety standard. Below, an example of a composition of clear glass and an example of a heat ray absorption glass composition are shown.

(Clear glass)
SiO _2: 70~73 mass%
Al ₂ O _3: 0.6~2.4 wt%
CaO: 7 to 12 mass%
MgO: 1.0-4.5 mass%
R ₂ O: 13 to 15 mass% (R is an alkali metal)
Fe total iron oxide in terms of _{2 O 3 (T-Fe 2} O 3): 0.08~0.14 wt%

(Heat absorption glass)
The composition of the heat-absorbing glass, for example, based on the composition of the clear glass, the proportion of the total iron oxide in terms of _{Fe 2 O 3 (T-Fe} 2 O 3) and 0.4 to 1.3 wt%, CeO ₂ ratio as 0-2 mass%, the proportion of TiO ₂ and 0 to 0.5 wt%, framework component of the glass (mainly, SiO ₂ and Al ₂ O ₃₎ to T-Fe ₂ O _3, CeO _The composition can be obtained by reducing the increase of ₂ and TiO ₂ .

  The type of the glass plate 10 is not limited to clear glass, heat ray absorbing glass, etc., and can be appropriately selected according to the embodiment. For example, the glass plate 10 may be a resin window such as an acrylic or polycarbonate resin having a refractive index of 1.4 to 1.6.

  Moreover, the thickness of the glass plate 10 according to the present embodiment may not be particularly limited. However, from the viewpoint of weight reduction, the thickness of the glass plate 10 may be set in the range of 2.2 to 5.1 mm, or may be set in the range of 2.4 to 3.8 mm, or 2. It may be set in the range of 7 to 3.2 mm. Furthermore, the thickness of the glass plate 10 may be set to 3.1 mm or less.

<Shield layer>
Next, the shielding layer 11 will be described. As illustrated in FIG. 1 and FIG. 2, in the present embodiment, the shielding layer 11 is laminated on the inner surface 13 inside the vehicle and is formed along the peripheral edge of the glass plate 10. Specifically, as illustrated in FIG. 1, the shielding layer 11 according to the present embodiment has a peripheral region 111 along the peripheral part of the glass plate 10 and a rectangular shape protruding downward from the upper side part of the glass plate 10. It can be divided into the projecting area 112. The peripheral region 111 blocks the incidence of light from the peripheral portion of the window glass 1. On the other hand, the protruding area 112 makes the imaging device 2 arranged inside the vehicle invisible from outside the vehicle.

  However, if the shielding layer 11 shields the photographing range of the photographing device 2, the photographing device 2 cannot photograph the situation in front of the vehicle. Therefore, in the present embodiment, a rectangular photographing window 113 is provided in the protruding region 112 of the shielding layer 11 at a position corresponding to the photographing device 2 so that the photographing device 2 can be in a situation outside the vehicle.

  As will be described later, the photographing window 113 is a region where the material of the shielding layer 11 is not laminated, and is configured to have a visible light transmittance that allows the photographing device 2 to photograph the situation outside the vehicle. For example, the photographing window 113 is configured so that the visible light transmittance is 70% or more. The transmittance can be measured by a spectroscopic measurement method specified in JIS Z 8722, as specified in JIS R 3212 (3.11 visible light transmittance test). In the present embodiment, the shooting window 113 is provided in the protruding area 112. That is, the photographing window 113 is provided independently of the non-shielding region 12 inside the shield layer 11 in the surface direction.

  The non-shielding region 12 is a region where the material of the shielding layer 11 is not laminated, like the photographing window 113. The driver and accompanying person sitting in the passenger seat confirm the traffic condition outside the vehicle through the non-shielding area 12. Therefore, the non-shielding region 12 is configured to have a visible light transmittance at least so that the traffic condition outside the vehicle can be visually recognized.

  Here, with reference to FIG. 3A and FIG. 3B, problems that may occur when the photographing device 2 photographs the situation outside the vehicle through the photographing window 113 will be described. FIG. 3A illustrates the behavior of the main light beam 60 and the sub light beam 61 in the window glass 1 according to this embodiment. Further, FIG. 3B illustrates the behavior of the main light flux 60 and the sub-light flux 61 when the shielding layer 11 (particularly, the blocking unit 114 described later) is not provided. In FIG. 3A, the widths of the main light flux 60 and the sub-light flux 61 are expressed as constant. However, this expression is for convenience of description, and does not indicate that the actual main light flux 60 and the sub-light flux 61 behave in this way.

  Strictly speaking, the main light flux 60 and the sub-light flux 61 are not parallel on the vehicle outer side as shown in FIG. 24, and do not match on the vehicle inner side. However, the distance between the light source and the windshield (window glass 1) is much larger than the thickness of the glass plate 10, and the angular difference between the main light flux and the sub-light flux and the positional deviation are minute amounts, so that in FIGS. 3A and 3B. It is noted that the two are parallel on the outside of the vehicle and coincide with each other on the inside of the vehicle, and the following mathematical expressions will be described on the premise of such conditions.

  As illustrated in FIG. 3A, the image capturing device 2 installed in the vehicle captures the situation outside the vehicle by receiving the main light flux 60 that has passed through the glass plate 10. The main light flux 60 is a light flux that enters the imaging device 2 without being reflected within the glass plate 10, and most of the light that enters from the outside of the vehicle behaves like the main light flux 60.

  However, since there is a difference in the refractive index between the glass plate 10 and the air, each surface (13, 14) of the glass plate 10 may reflect part of the light incident from the outside of the vehicle. Then, in the present embodiment, the glass plate 10 is arranged in an inclined posture. Therefore, the sub-light flux 61 emitted from the same place as the main light flux 60 may be reflected in the glass plate 10 and enter the photographing device 2 almost overlapping the optical path of the main light flux 60.

  Specifically, in the example of FIG. 3A, the glass plate 10 is arranged so as to incline from the vehicle outer side to the vehicle inner side with respect to the vertical direction. Therefore, the light incident on the glass plate 10 can be shifted upward in the glass plate 10 by being reflected by the inner surface 13 of the glass plate 10 and further reflected by the outer surface 14.

  That is, the sub-beam 61 that travels below the main beam 60 is reflected by the inner surface 13 of the glass plate 10 and then by the outer surface 14, and shifts upward in the glass plate 10. As a result, the sub-light flux 61 can enter the optical path of the main light flux 60 so as to substantially overlap with the optical path. The upward direction of the glass plate 10 corresponds to the "direction in which the sub-beam can shift" of the present invention. However, the direction in which the sub-light flux can shift is not limited to the upward direction of the glass plate 10, but is determined by the tilt direction of the glass plate 10.

  Therefore, the sub-light flux 61 emitted from the same place as the main light flux 60 due to the reflection in the glass plate 10 is finally received by the imaging device 2 along the almost same optical path as that of the main light flux 60. May be done. Then, if light emitted from the same place and having a slight angle difference is received by this, a double image may occur in a captured image acquired by the imaging device 2.

  Therefore, in the present embodiment, in order to prevent the occurrence of such a double image, a blocking unit 114 that blocks the progress of the sub-beam 61 is provided in a region below the photographing window 113. The blocking unit 114 is specifically configured by a part of the shielding layer 11. That is, the blocking portion 114 is arranged on the inner surface 13 of the glass plate 10.

  Therefore, the blocking unit 114 suppresses the reflection of the sub-beam 61 on the inner surface 13, that is, the sub-beam 61 from proceeding in the direction of the arrow 62, so that the sub-beam 61 enters near the optical path of the main beam 60. It is possible to prevent the occurrence of a double image due to this. Therefore, in the present embodiment, at least a part of the shielding layer 11, that is, the blocking portion 114 is formed of an antireflection member that prevents reflection of the sub-light flux 61. The antireflection member is not particularly limited as long as it is a member that prevents or reduces light rays from being reflected by the glass plate, and may be, for example, a ceramic or the like that forms the shielding layer 11 described later. Further, for example, as a method of forming the blocking portion 114, a method of attaching an ink, a paint, a metal film layer or the like having a low reflectance to the surface of the glass plate 10 by means of printing, painting, coating, etc., or a light absorbing material. A method of adhering the plate material constituted by the above to the surface of the glass plate 10, a method of providing minute unevenness on the portion of the glass plate 10 by a means such as sand scraping or etching to form a light scattering surface, only near the surface of the portion Examples thereof include a method of chemically modifying to reduce the reflectance and a method of applying an antireflection coating on the surface of the glass plate 10.

  Next, the positional relationship between the blocking unit 114 and the main light beam 60 will be described. Assuming that the blocking unit 114 is not provided, the amount of shift (shift amount) of the sub-light flux 61 toward the main light flux 60 due to reflection within the glass plate 10 arranged in a tilted posture is calculated by the above equation. It can be defined by the length L of (1). That is, as shown in FIG. 3B, when the incident angle of the horizontal ray incident on the outer surface 14 is θ, the refraction angle is θa, and the thickness and the refractive index of the glass plate 10 are T and n, respectively, the refraction of light is From the general rule, the following relational expressions of Expression 4 and Expression 5 are satisfied.

Then, the above equation (1) can be derived by solving the relational expressions of the equations 4 and 5 for L. The inclination angle Φ of the glass plate 10 with respect to the horizontal direction and the incident angle θ satisfy the following relational expression (6).

  Therefore, in the present embodiment, as shown in FIG. 3A, the upper end portion of the blocking portion 114 travels in the upward direction of the glass plate 10 by a sub-beam that can enter a position separated from the upper end portion by the length L. Shut off. That is, the range in which the sub-beam 61 can be prevented from entering the vicinity of the optical path of the main beam 60 by the blocking unit 114 is the range of the length L shown in FIG. 3A. However, in FIG. 3A, when the width W of the blocking portion 114 in the up-down direction of the glass plate 10 is less than this length L, a region where the sub-beam 61 enters a part of the range of the length L shown in FIG. 3A. Occurs, and it is impossible to prevent the sub-light flux 61 from entering the entire range.

  Therefore, it is preferable that the width W of the blocking portion 114 be configured to be the length L or more. In addition, it is preferable that the blocking unit 114 be arranged so that the main light flux 60 passes through the range of the length L from the upper end of the blocking unit 114 in the upward direction of the glass plate 10. As a result, it is possible to effectively suppress the occurrence of a double image due to the sub-light flux 61 entering near the optical path of the main light flux 60.

  However, the width W of the blocking unit 114 is not limited to such an example, and may be larger than the width of the passing portion of the inner surface 13 of the main light flux 60, so that the width of the main light flux required by the imaging device is narrow. If so, the length may be less than the length L. Further, the position of the blocking unit 114 may be appropriately selected according to the embodiment as long as the blocking unit 114 can prevent the double image from occurring in at least a part of the captured image.

  When the glass plate 10 stands up in a substantially vertical direction, the incident angle θ of the light traveling in the horizontal direction with respect to the glass plate 10 becomes small, which reduces the length L that determines the shift amount of the sub-beam 61. .. Therefore, there is a possibility that the size of the photographing window 113 sufficient for photographing by the photographing device 2 cannot be secured. However, when the incident angle θ becomes small, the angle difference between the main light beam 60 and the sub-light beam 61 also becomes very small, and the deviation of the double image hardly occurs. Therefore, the countermeasure against the double image becomes unnecessary. Therefore, the present invention is particularly effective when the value of the incident angle θ is large to some extent.

Therefore, it is particularly preferable to set the minimum value of the incident angle θ to 10 degrees and use the length L ₀ satisfying the above formula (2) as a reference for the length L. That is, it is particularly preferable that the width W of the blocking portion 114 be configured to be the length L ₀ or more. In addition, it is preferable that the blocking unit 114 is arranged so that the main light flux 60 passes through the range of the length L ₀ from the upper end of the blocking unit 114 in the upward direction of the glass plate 10. This makes it possible to effectively suppress the occurrence of a double image due to the sub-light flux 61 entering the vicinity of the optical path of the main light flux 60 while appropriately maintaining the width H of the photographing window 113 described later.

  The upper limit value of the width W of the blocking portion 114 may be appropriately set according to the embodiment, and is preferably set to a length that does not overlap the driver's visual field range. Here, the visual field range in which the driver who drives the vehicle checks the traffic conditions when driving is a range that the driver in the driver's seat pays attention to when driving, and can be appropriately set according to the embodiment. Is. For example, the test area A defined in JIS R 3212 (1998, “Test method for safety glass for automobiles”) may be adopted as the visual field range.

  Since the main light flux 60 in FIG. 3A corresponds to the light source on the optical axis of the image capturing apparatus, the thickness E of the light flux has a constant value in the optical axis direction. However, since the actual photographing device has a certain viewing angle as shown in FIG. 2, the area required for the photographing window 113 varies depending on the distance between the photographing device 2 and the inner surface 13. The area required for the photographing window 113 has a minimum value when the entrance pupil of the photographing device 2 matches the inner surface 13. FIG. 4 is a view of the relationship between the photographing window 113 and the entrance pupil 24 in such a case as seen from the optical axis direction and the lateral direction of the photographing apparatus, and R is the diameter of the entrance pupil.

  Therefore, when the image capturing device 2 is installed in the vehicle so that the entrance pupil 24 of the optical system constituting the image capturing device 2 is located on the image capturing window 113, the light rays required for image capturing by the image capturing device 2 will pass through the image capturing window 113. The size when passing is the minimum value R. Therefore, in this embodiment, the vertical width H of the imaging window 113 and the diameter R of the entrance pupil 24 are configured to satisfy the above expression (3). As a result, it is possible to secure a size of the photographing window 113 that is sufficient so that the shielding layer 11 does not block the photographing range of the photographing device 2. In addition, the above-mentioned formula (3), it is possible to set the guideline of the size which relates to the minimum limit of photographing window 113, the design of photographing window 113 becomes easy. Note that, for example, when the imaging device 2 is configured by a camera having a focal length f = 8 mm and an aperture ratio F = 2, the diameter R of the entrance pupil 24 is 4 mm.

  However, when the width H of the imaging window 113 is made to coincide with the diameter R of the entrance pupil 24, a part of the light beam necessary for the imaging of the imaging device 2 is generated by the shielding layer 11 even if the position of the imaging device 2 is slightly displaced. It will be blocked. To prevent such a case, H may be larger than R.

Further, when the shooting window 113 is large, unnecessary light for shooting may enter from the shooting window 113, which may reduce the contrast of the shot image and deteriorate the image quality. From this point of view, the area of the photographing window 113 is preferably 3000 mm ² or less. By setting the area of the photographing window 113 to be 3000 mm ² or less, the size of the photographing window 113 can be made relatively small, and it is possible to reduce the incidence of unnecessary light from the photographing window 113 for photographing. Therefore, according to the configuration, it is possible to improve the contrast of the captured image captured through the capturing window 113.

  Further, as shown in FIG. 8 described later, the window glass 1 according to the present embodiment is heated at approximately 650 degrees in the molding process. Furthermore, as described later, the material of the shielding layer 11 is, for example, dark-colored ceramic such as black. Therefore, the area of the shield layer 11 absorbs more heat than the area where the ceramics are not laminated (for example, the area of the photographing window 113). Further, since the ceramic that is the material of the shielding layer 11 has a different coefficient of thermal expansion from the glass plate 10, compressive stress and tensile stress are generated in the region where the shielding layer 11 is formed during the molding process. As a result, glass-shaped distortion easily occurs at the boundary between the region where the shielding layer 11 is formed and the region where the shielding layer 11 is not formed.

According to the embodiment described later, this distortion is formed within a range of about 8 mm from the peripheral portion of the photographing window 113. Therefore, in order to prevent the captured image from being deformed by the distorted area, it is preferable to secure a sufficient size of the shooting window 113 so that the shooting range of the shooting device 2 does not overlap the distorted area. For example, in order to arrange a strained area having a width of 8 mm outside the entrance pupil 24 having a diameter of 4 mm when the inclination angle φ of the window glass is 30 °, the glass is obtained by projecting the entrance pupil in the optical axis direction. In terms of the surface, an ellipse having a major axis of 8 mm in the vertical direction and a minor axis of 4 mm in the lateral direction is formed. Further, in consideration of the possibility that the position where the image capturing device 2 is installed is displaced, the area of the image capturing window 113 may be set to 1000 mm ² or more.

  The width of the shooting window 113 in the left-right direction can be handled in the same manner as the width H of the shooting window 113 in the up-down direction. However, the width of the shooting window 113 in the left-right direction does not have to be the same as the width H of the shooting window 113 in the up-down direction. Further, the shape of the photographing window 113 is not limited to the rectangular shape, and can be appropriately selected according to the embodiment. For example, the shape of the photographing window 113 may be trapezoidal, circular, elliptical, or the like.

  Further, a heater for preventing dew condensation on the photographing window 113 may be installed around the photographing window 113. With this heater, dew condensation on the photographing window 113 can be prevented and the visual field of the photographing device 2 can be maintained in a good state. However, when the size of the photographing window 113 is relatively large, the central area of the photographing window 113 is far from the heater installed around the photographing window 113, so that dew condensation may easily remain. On the other hand, according to the present embodiment, since the size of the photographing window 113 can be made relatively small, it is possible to prevent dew condensation from easily remaining in the central region of the photographing window 113. Moreover, since the amount of heat for preventing dew condensation is small, it is possible to suppress power consumption in the heater.

  Next, the material of the shielding layer 11 including the blocking portion 114 will be described. The material of the shielding layer 11 may be appropriately selected according to the embodiment as long as it can shield the field of view from the outside of the vehicle. For example, a dark ceramic such as black, brown, gray, or dark blue is used. Good. However, as described above, in the present embodiment, the blocking unit 114 configured by a part of the blocking layer 11 blocks the progress of the sub-beam 61 on the inner surface 13 side. Therefore, as described above, the antireflection member that prevents or reduces the reflection of light such as black ceramic is selected as the material of the shielding layer 11.

  When the black ceramic is selected as the material of the shielding layer 11, the black ceramic is laminated on the peripheral portion of the inner surface 13 of the glass plate 10 by screen printing or the like, and the laminated ceramic is heated together with the glass plate 10. Thereby, the shielding layer 11 can be formed on the peripheral portion of the window glass 1. Further, when the black ceramic is printed, a region in which the black ceramic is not printed is provided. Thereby, the photographing window 113 can be formed. Various materials can be used for the ceramic used for the shield layer 11. For example, a ceramic having the composition shown in Table 1 below can be used for the shielding layer 11. Further, the blocking portion 114 may be formed of a material different from that of the other regions of the shielding layer 11.

* 1, Main component: Copper oxide, chromium oxide, iron oxide and manganese oxide * 2, Main component: Bismuth borosilicate, Zinc borosilicate

<Imager>
Next, the configuration of the photographing device 2 will be described with reference to FIGS. 5 and 6. FIG. 5 shows an example of the configuration of the image capturing apparatus 2 according to this embodiment. In addition, FIG. 6 illustrates an example of the imaging device 250 in which the entrance pupil exists inside the lens system (optical system).

  The image capturing apparatus 2 according to the present embodiment passes through the lens system 21 having the four lenses 211 to 214, the aperture stop 22 arranged between the third lens 213 and the fourth lens 214, and the lens system 21. An image sensor 23 that captures an image with light. In the present embodiment, the entrance pupil 24, which is a real image of the aperture stop 22 and is formed by the lenses 211 to 213 arranged on the subject side (left side in FIG. 5) of the aperture stop 22, is on the subject side of the lens system 21. Located in.

  In the general imaging device 250 illustrated in FIG. 6, the entrance pupil 255, which is a virtual image of the aperture stop 253, is located inside the lens system. Therefore, the distance between the entrance pupil 255 and the window glass 1 cannot be set below a certain value. On the other hand, in the present embodiment shown in FIG. 5, the optical system of the image capturing apparatus 2 according to the present embodiment is configured such that the entrance pupil 24 is closer to the subject than the optical components. Therefore, in the present embodiment, since there is no loss corresponding to the length of the optical component, the distance between the entrance pupil 24 and the window glass 1 can be reduced, and the distance can be set to zero or a negative value. Is also possible. However, in the present embodiment, the adoption of the general imaging device 250 is not excluded. That is, if the lens system of the image capturing device 250 is sufficiently small, the distance between the entrance pupil 255 and the window glass 1 also becomes small, so that the image capturing device 250 may be used instead of the image capturing device 2.

  The aperture stop 22 defines the thickness of the light flux that enters the image sensor 23. The diameter size of the aperture stop 22 may be variable. Note that, for example, when the imaging device 2 is configured as a camera having a focal length f = 8 mm and an aperture ratio F = 2, the diameter of the entrance pupil 24 which is an image of the aperture stop 22 is 4 mm.

  The image sensor 23 forms an image of the subject by forming an image of the incident light 201 (main light flux 60) that has passed through the lens system 21 on the light receiving plane, and acquires a captured image. The image sensor 23 is, for example, an image sensor including a CCD or the like. However, the type of the image sensor 23 is not limited to CCD, and CMOS or the like may be appropriately selected according to the embodiment. The captured image acquired may be a moving image or a still image. The format of the captured image acquired can be appropriately selected according to the embodiment.

  Such an imaging device 2 can be arranged in the upper part of the vehicle so as to be hidden by the protruding region 112 of the shielding layer 11. For example, the imaging device 2 can be arranged near the support portion of the room mirror.

  Here, as will be described later, the present inventors have determined that the optical distance between the entrance pupil 24 of the lens system 21 and the photographing window 113 of the window glass 1 in the optical axis direction of the photographing apparatus 2 (left-right direction in FIG. 5). It has been found that by disposing the photographing device 2 within the range of 10 mm in the front and rear, the distortion amount of the image photographed through the photographing window 113 is unlikely to change. Therefore, in the present embodiment, the optical distance between the entrance pupil 24 of the lens system 21 and the photographing window 113 of the window glass 1 in the optical axis direction of the photographing device 2 is within 10 mm in the front and rear. The imaging device 2 is arranged in this manner. With this, it is possible to prevent the distortion amount of the captured image captured through the capturing window 113 from fluctuating significantly due to the manufacturing error of the window glass 1, and the captured image captured without considering the individual difference of the window glass 1. A correction value for correcting an image can be uniformly set.

<In-vehicle system>
Next, the in-vehicle system 5 including the image capturing device 2 and the image processing device 3 will be described with reference to FIG. 7. FIG. 7 illustrates the configuration of the in-vehicle system 5. As illustrated in FIG. 7, the vehicle-mounted system 5 according to the present embodiment includes the above-described image capturing device 2 and the image processing device 3 connected to the image capturing device 2.

  The image processing device 3 is a device that processes a captured image acquired by the imaging device 2. The image processing device 3 has, for example, as a hardware configuration, general hardware such as a storage unit 31, a control unit 32, and an input / output unit 33 that are connected by a bus. However, the hardware configuration of the image processing device 3 is not limited to such an example, and the specific hardware configuration of the image processing device 3 is appropriately added or omitted according to the embodiment. And can be added.

  The storage unit 31 stores various data and programs used in the processing executed by the control unit 32 (not shown). The storage unit 31 may be realized by, for example, a hard disk or a recording medium such as a USB memory. The various data and programs stored in the storage unit 31 may be obtained from a recording medium such as a CD (Compact Disc) or a DVD (Digital Versatile Disc). Further, the storage unit 31 may be called an auxiliary storage device.

  As described above, the glass plate 10 is arranged in an inclined posture with respect to the vertical direction and is curved. Then, the photographing device 2 photographs the situation outside the vehicle through such a glass plate 10. Therefore, the captured image acquired by the imaging device 2 is deformed according to the posture, shape, refractive index, optical defect, etc. of the glass plate 10. Therefore, the storage unit 31 may store correction data for correcting such an image deformed by the glass plate 10.

  The control unit 32 includes one or a plurality of processors such as a microprocessor or a CPU (Central Processing Unit), and peripheral circuits (ROM (Read Only Memory), RAM (Random Access Memory), interface circuit used for the processing of this processor. Etc.) and. The ROM, RAM and the like may be called a main storage device in the sense that they are arranged in an address space handled by the processor in the control unit 32. The control unit 32 functions as the image processing unit 321 by executing various data and programs stored in the storage unit 31.

  The image processing unit 321 processes a captured image acquired by the imaging device 2. The processing of the captured image can be appropriately selected according to the embodiment. For example, the image processing unit 321 may recognize the subject included in the captured image by analyzing the captured image by pattern matching or the like. In this embodiment, the window glass 1 is a windshield, and the image capturing device 2 captures a situation in front of the vehicle. Therefore, the image processing unit 321 may further determine, based on the subject recognition, whether or not a living thing such as a human is captured in front of the vehicle. Then, when a person is photographed in front of the vehicle, the image processing unit 321 may output a warning message by a predetermined method. Further, for example, the image processing unit 321 may perform a predetermined processing process on the captured image. Then, the image processing unit 321 may output the processed captured image to a display device (not shown) such as a display connected to the image processing device 3.

  The input / output unit 33 is one or a plurality of interfaces for transmitting / receiving data to / from a device existing outside the image processing device 3. The input / output unit 33 is, for example, an interface for connecting with a user interface or an interface such as a USB (Universal Serial Bus). In the present embodiment, the image processing device 3 is connected to the photographing device 2 via the input / output unit 33 and acquires the photographed image photographed by the photographing device 2.

  As such an image processing apparatus 3, a general-purpose apparatus such as a PC (Personal Computer) or a tablet terminal may be used in addition to an apparatus designed exclusively for the provided service.

§2 Manufacturing Method Next, a manufacturing method of the window glass 1 according to the present embodiment will be described with reference to FIG. FIG. 8 schematically illustrates the forming process of the glass plate 10 of the window glass 1 according to this embodiment. The method for manufacturing the window glass 1 described below is merely an example, and each step may be changed as much as possible. Further, in the manufacturing process described below, steps can be omitted, replaced, and added as appropriate according to the embodiment.

  As illustrated in FIG. 8, in this manufacturing line, a heating furnace 80 and a molding device 82 are arranged in this order from upstream to downstream. A roller conveyor 81 is arranged from the heating furnace 80 to the forming device 82 and the downstream side thereof, and the glass plate 10 to be processed is conveyed by the roller conveyor 81. The glass plate 10 is formed in a flat plate shape, and after the shielding layer 11 is laminated on the inner surface 13, the glass plate 10 is carried into the heating furnace 80.

  The heating furnace 80 may have various configurations, but may be, for example, an electric heating furnace. This heating furnace 80 is provided with a rectangular tube-shaped furnace main body whose upstream and downstream ends are open, and a roller conveyor 81 is arranged therein from upstream to downstream. A heater (not shown) is arranged on each of the upper surface, the lower surface, and the pair of side surfaces of the inner wall surface of the furnace body. Heat to near.

  The molding device 82 is configured to press the glass plate 10 with the upper mold 821 and the lower mold 822 to mold it into a predetermined shape. The upper die 821 has a downward convex curved surface shape that covers the entire upper surface of the glass plate 10, and is configured to be vertically movable. The lower mold 822 is formed in a frame shape corresponding to the peripheral edge of the glass plate 10, and the upper surface thereof has a curved shape so as to correspond to the upper mold 821. With this configuration, the glass plate 10 is press-molded between the upper mold 821 and the lower mold 822 to be molded into a final curved shape. A roller conveyor 81 is arranged in the frame of the lower die 822, and the roller conveyor 81 is vertically movable so as to pass through the frame of the lower die 822. Although not shown, a slow cooling device (not shown) is arranged on the downstream side of the forming device 82 to cool the formed glass sheet.

  Here, the heating furnace 80 is heated at about 650 degrees. At this time, since the ceramic that is the material of the shielding layer 11 has a dark color such as black, the amount of heat absorption is higher than that of the region where the ceramics are not stacked, for example, the region of the photographing window 113 and the non-shielding region 12. Will increase. Since the ceramic forming the shielding layer 11 has a different coefficient of thermal expansion from the glass plate 10, a compressive stress and a tensile stress are generated in this forming step in the region where the shielding layer 11 is formed. Therefore, in the peripheral portion of the photographing window 113 and in the boundary portion between the non-shielding region 12 and the shielding layer 11, a strained region in which a strain as described below occurs is formed.

  Therefore, as described above, the size of the photographing window may be set in consideration of the width of the distorted area. That is, for example, when the inclination angle φ of the window glass is 30 °, the photographing window 113 has a vertical major axis of 24 mm in order to arrange a strained area having a width of 8 mm outside the entrance pupil 24 having a diameter of 4 mm. Alternatively, it may be configured to be larger than an ellipse having a short diameter of 20 mm in the left-right direction. As a result, the size of the photographing window 113 can be made relatively small while avoiding the influence of distortion on the photographing device 2.

  The roller conveyor 81 as described above is a known one, and a plurality of rollers 811 whose both ends are rotatably supported are arranged at predetermined intervals. There are various methods for driving each roller 811, but for example, a sprocket can be attached to the end of each roller 811 and a chain can be wound around each sprocket for driving. Then, by adjusting the rotation speed of each roller 811, the conveyance speed of the glass plate 10 can also be adjusted. The lower mold 822 of the molding device 82 may be in contact with the entire surface of the glass plate 10. In addition, the shape of the upper mold and the lower mold of the molding device 82 is not particularly limited as long as it molds the glass plate 10.

§3 Characteristics As described above, in the window glass 1 according to the present embodiment, the image capturing device 2 installed inside the vehicle captures an image of the outside of the vehicle through the glass plate 10 arranged in a tilted posture. Therefore, there is a possibility that a double image may occur in a captured image obtained by the image capturing apparatus 2 due to the sub-light flux 61 emitted from the same location as the main light flux 60 entering near the optical path of the main light flux 60. ..

  On the other hand, in the present embodiment, the cutoff that blocks the progress of the sub-beam 61 at a position where the inner surface 13 of the glass plate 10 and the optical path of the sub-beam 61 overlap and does not block the optical path of the main beam 60. A section 114 is provided. Therefore, the blocking unit 114 can block the progress of the sub-beam 61 without blocking the progress of the main beam 60, and prevent the sub-beam 61 from reaching the imaging device 2. Therefore, according to this configuration, the blocking unit 114 can prevent a double image from appearing in a captured image acquired by the imaging device 2.

  In addition, in the present embodiment, the blocking section 114 is configured as a part of the blocking layer 11. Therefore, in the present embodiment, the blocking unit 114 does not have to be formed separately from the blocking layer 11, and the blocking unit 114 can be formed in the process of forming the blocking layer 11. Therefore, according to the present embodiment, it is possible to prevent a double image from appearing in a captured image captured by the image capturing device 2 with a simple configuration.

Various standards exist for the shielding layer 11. Among these standards, there is a standard that defines the width of the shielding layer 11. On the other hand, the inventors of the present invention have found a problem that a double image is generated in a captured image, and in order to solve this problem efficiently, the blocking portion formed by a part of the shielding layer 11 For 114, lower limits for lengths L, L _0, etc. were created. That is, the inventors of the present invention go beyond the situation where the width of the shielding layer 11 is simply determined, and further define the width of the blocking portion 114 that is formed by a part of the shielding layer 11 to obtain a captured image. It effectively solved the problem that a double image was generated in the.

§4 Modifications The embodiments of the present invention have been described in detail above, but the above description is merely an example of the present invention in all respects. It goes without saying that various improvements and modifications can be made without departing from the scope of the present invention. For example, with respect to the respective constituent elements of the window glass 1, the image capturing apparatus 2, and the image processing apparatus 3, the constituent elements may be appropriately omitted, replaced, or added depending on the embodiment. For example, the following changes are possible. In addition, below, the same code | symbol is used about the same component as the said embodiment, and description was abbreviate | omitted suitably.

<4.1>
For example, in the above embodiment, the window glass 1 is a windshield for an automobile. However, the window glass to which the present invention is applicable is not limited to the windshield of an automobile, and can be appropriately selected according to the embodiment.

<4.2>
In addition, for example, regarding the above-described specific configuration of the glass plate 10, the omission, change, replacement, and addition of the constituent elements may be appropriately performed depending on the embodiment. For example, although the glass plate 10 has a shape curved toward the front side, it may have a flat shape. The glass plate 10 is formed in a substantially rectangular shape. However, the shape of the glass plate 10 is not limited to the above embodiment, and can be appropriately selected according to the embodiment.

<4.3>
Further, for example, in the above embodiment, the shielding layer 11 is provided along the peripheral edge of the window glass 1. However, the region where the shielding layer 11 is provided can be set as appropriate according to the embodiment. However, if the shielding layer 11 overlaps the driver's visual field range, the shielding layer 11 hinders the driver's visual field during driving. Therefore, it is preferable to set the region of the shielding layer 11 so as not to overlap the driver's visual field range.

<4.4>
Further, for example, in the above embodiment, the shielding layer 11 is laminated on the inner surface 13. However, the surface on which the shielding layer 11 is laminated is not limited to the inner surface 13 and may be the outer surface 14. Further, the shielding layer 11 may be laminated on both the inner surface 13 and the outer surface 14.

  FIG. 9 illustrates a window glass 1A according to this modification. In this window glass 1A, the shielding layer 11 including the shielding portion 114 is laminated on the outer surface 14 of the glass plate 10. Therefore, as illustrated in FIG. 9, the blocking unit 114 can prevent the sub-beam 61 from entering the optical path of the main beam 60 by preventing the sub-beam 61 from passing therethrough.

  Therefore, in this case, at least a part of the shielding layer 11, that is, the shielding portion 114 is formed of a transmission preventing member that prevents the sub-light flux 61 from transmitting. The transmission preventing member is not particularly limited as long as it is a member that prevents or reduces light rays from passing through the glass plate, and is, for example, ceramic or the like forming the shielding layer 11. Further, for example, as a method of forming the permeation-preventing member, a method of sticking an opaque ink, a paint, a metal film or the like on the surface of the glass plate 10 by means of printing, painting, coating or the like, or a means such as sand picking, etching or the like is used. Examples thereof include a method of providing minute unevenness on the portion of the glass plate 10 to form a light scattering surface, and a method of chemically modifying only the vicinity of the surface of the portion to make it opaque.

  When the blocking unit 114 is formed of the permeation-preventing member as described above, the blocking unit 114 may be disposed on the vehicle outer side than the inner surface 13, and may be disposed on a portion other than the outer surface 14. For example, when the glass plate 10 is made of laminated glass described later, the blocking portion 114 is provided on the car outside surface of the outside glass plate, on the car inside surface of the outside glass plate, and on the inside glass plate of the outside glass plate. It may be arranged on a surface outside the vehicle.

<4.5>
Further, for example, in the above-mentioned embodiment, it is configured by one glass plate. However, the glass plate 10 may be made of laminated glass in which the outer glass plate and the inner glass plate are bonded to each other via an intermediate film.

  FIG. 10 illustrates a window glass 1B according to this modification. The window glass 1B includes laminated glass in which an outer glass plate 15 and an inner glass plate 16 are bonded to each other via an intermediate film 17. In the following description, for convenience of description, the outer surface of the outer glass plate 15 is referred to as a “first surface”, the inner surface of the outer glass plate 15 is referred to as a “second surface”, and the inner glass plate 16 is referred to as a “second surface”. The surface on the vehicle outer side is called the “third surface” and the surface of the inner glass plate 16 on the vehicle inner side is called the “fourth surface”.

  In the modification illustrated in FIG. 10, the blocking portion 114 (shielding layer 11) is laminated on the second surface 152. However, the surface on which the blocking unit 114 is laminated is not limited to the second surface 152, and may be the first surface 151, the third surface 161, or the fourth surface 162. In addition, the blocking unit 114 may be provided on a plurality of surfaces of the first surface 151 to the fourth surface 162.

  Here, the outer glass plate 15 and the inner glass plate 16 can be formed of the same material as that of the glass plate 10. Further, the intermediate film 17 can be formed of a material having the same refractive index as the outer glass plate 15 and the inner glass plate 16. Therefore, reflection and refraction of light that may occur at the boundary between the outer glass plate 15 and the intermediate film 17 and at the boundary between the intermediate film 17 and the inner glass plate 16 are extremely small, and therefore need not be considered.

  Therefore, when the shielding layer 11 is disposed on the first surface 151, the second surface 152, or the third surface 161, at least a part of the shielding layer 11, that is, the shielding unit 114 prevents the transmission of the sub-beam. It is composed of a permeation preventing member. On the other hand, when the shielding layer 11 is arranged on the fourth surface 162, at least a part of the shielding layer 11, that is, the shielding unit 114 is formed of an antireflection member that prevents reflection of the sub-beam.

  The thickness of the laminated glass is not particularly limited, but from the viewpoint of weight reduction, the total thickness of the outer glass plate 15 and the inner glass plate 16 is preferably set to 2.4 to 4.6 mm. It is more preferably 6 to 3.8 mm, and particularly preferably 2.7 to 3.2 mm. In order to reduce the weight of the laminated glass, the total thickness of the outer glass plate 15 and the inner glass plate 16 may be reduced. The thickness of each of the outer glass plate 15 and the inner glass plate 16 is not particularly limited, but the thickness of each of the outer glass plate 15 and the inner glass plate 16 can be determined as follows, for example.

  That is, the outer glass plate 15 is mainly required to have durability and impact resistance against the impact of flying objects such as pebbles. On the other hand, as the thickness of the outer glass plate 15 is increased, the weight is increased, which is not preferable. From this viewpoint, the thickness of the outer glass plate 15 is preferably 1.8 to 2.3 mm, and more preferably 1.9 to 2.1 mm. Which thickness is adopted can be appropriately determined according to the embodiment.

  The thickness of the inner glass plate 16 can be made equal to the thickness of the outer glass plate 15, but the thickness can be made smaller than that of the outer glass plate 15 in order to reduce the weight of the laminated glass, for example. Specifically, considering the strength of the glass, the thickness of the inner glass plate 16 is preferably 0.6 to 2.0 mm, more preferably 0.8 to 1.6 mm, and 0.8. It is particularly preferable that it is ˜1.4 mm. Furthermore, the thickness of the inner glass plate 16 is preferably 1.0 to 1.3 mm. Which thickness is adopted also for the inner glass plate 16 can be appropriately determined according to the embodiment.

  Further, the intermediate film 17 can have various configurations according to the embodiment, and for example, can have a three-layer structure in which a soft core layer is sandwiched between a pair of outer layers that are harder than this. .. By thus forming the intermediate film 17 with a plurality of soft layers and hard layers, the damage resistance and sound insulation of the laminated glass can be improved.

  Further, the material of the intermediate film 17 is not particularly limited and can be appropriately selected according to the embodiment. For example, when the intermediate film 17 is composed of a plurality of layers having different hardness as described above, polyvinyl butyral resin (PVB) can be used for the hard outer layer. This polyvinyl butyral resin (PVB) is preferable as a material for the outer layer because it has excellent adhesiveness to each glass plate (15, 16) and penetration resistance. Further, for the soft core layer, an ethylene vinyl acetate resin (EVA) or a polyvinyl acetal resin softer than the polyvinyl butyral resin used for the outer layer can be used.

  In general, the hardness of the polyvinyl acetal resin is (a) the degree of polymerization of polyvinyl alcohol as a starting material, (b) the degree of acetalization, (c) the type of plasticizer, (d) the proportion of the plasticizer added, etc. Can be controlled by. Therefore, the hard polyvinyl acetal resin used for the outer layer and the soft polyvinyl acetal resin used for the core layer may be prepared by appropriately adjusting at least one of the conditions (a) to (d).

  Further, the hardness of the polyvinyl acetal resin can be controlled by the type of aldehyde used for acetalization, co-acetalization with a plurality of types of aldehydes, or pure acetalization with a single type of aldehyde. Although it cannot be generally stated, a polyvinyl acetal resin obtained by using an aldehyde having a large number of carbon tends to be soft. Therefore, for example, when the outer layer is made of polyvinyl butyral resin, the core layer has an aldehyde having 5 or more carbon atoms (for example, n-hexylaldehyde, 2-ethylbutyraldehyde, n-heptylaldehyde, n-). It is possible to use a polyvinyl acetal resin obtained by acetalizing octyl aldehyde) with polyvinyl alcohol.

  The total thickness of the intermediate film 17 can be appropriately set according to the embodiment, and can be, for example, 0.3 to 6.0 mm, preferably 0.5 to 4.0 mm, It is more preferably 0.6 to 2.0 mm. For example, when the intermediate film 17 has a three-layer structure including a core layer and a pair of outer layers sandwiching the core layer, the thickness of the core layer is preferably 0.1 to 2.0 mm, and is 0.1 to 2.0 mm. More preferably, it is ˜0.6 mm. On the other hand, the thickness of each outer layer is preferably larger than the thickness of the core layer, specifically, it is preferably 0.1 to 2.0 mm, and more preferably 0.1 to 1.0 mm. preferable.

  A method for producing such an intermediate film 17 is not particularly limited, but, for example, a resin component such as the polyvinyl acetal resin described above, a plasticizer, and optionally other additives are blended, and after uniformly kneading, Examples thereof include a method of extruding each layer at once, and a method of laminating two or more resin films formed by this method by a pressing method, a laminating method, or the like. The resin film before lamination used in the lamination method such as the pressing method and the lamination method may have a single-layer structure or a multi-layer structure. Further, the intermediate film 17 may be formed of a single layer, instead of being formed of a plurality of layers as described above. When the glass plate 10 is composed of a plurality of layers, the thickness T of the glass plate 10 in the formulas (1) and (2) is the sum of the thicknesses of all layers, and the refractive index n is the thickness ratio. Let it be the average refractive index distributed in.

<4.6>
Further, in the above-described embodiment, the blocking section 114 that blocks the progress of the sub-beam 61 is configured as a part of the blocking layer 11. However, the configuration of the blocking unit is not limited to such an example, and various configurations are possible according to the embodiment. For example, another form of the blocking unit 114 can be illustrated by FIGS. 11 and 12.

  FIG. 11 is a plan view illustrating a window glass 1C according to this modification. In addition, FIG. 12 is a cross-sectional view illustrating a window glass 1C according to this modification. 11 and 12, the shield layer 11 is omitted. That is, as illustrated in FIGS. 11 and 12, the blocking portion 18 may be formed independently instead of as a part of the blocking layer 11. In this case, similarly to the blocking unit 114, the size and position of the blocking unit 18 considers the transmission region of the main light beam 60 received by the imaging device 2 so as to efficiently block the progress of the sub-light beam 61. Can be set.

  That is, as illustrated in FIG. 12, when the glass plate 10 is arranged so as to incline from the vehicle outer side to the vehicle inner side with respect to the vertical direction, the width W of the blocking portion 18 in the vertical direction of the glass plate 10 is It can be formed to have a length L or more that satisfies the above formula 1. In addition, the blocking unit 18 allows the main light flux 60 to travel between the upper end of the blocking unit 18 and a position separated from the upper end of the blocking unit 18 by the length L in the upward direction of the glass plate 10. Can be placed. As a result, it is possible to efficiently prevent a double image from being generated in the captured image obtained by the image capturing device 2.

  In addition, in the modification example illustrated in FIGS. 11 and 12, the blocking portion 18 is arranged on the inner surface 13 of the glass plate 10. However, the blocking portion 18 may be arranged on the outer surface 14 instead of the inner surface 13. When the blocking portion 18 is arranged on the inner surface 13, the blocking portion 18 is composed of the antireflection member. On the other hand, when the blocking portion 18 is arranged on the outer surface 14, the blocking portion 18 is composed of the permeation preventing member. As described above, the blocking unit that blocks the progress of the sub-beam may be formed with a simple configuration. This makes it possible to prevent the occurrence of double images at low cost.

  In addition, as illustrated in FIG. 25, the blocking unit may be configured by a sheet material or the like that adheres to the glass plate. FIG. 25 illustrates the blocking unit 71 according to this modification. The sheet material 70 illustrated in FIG. 25 is bonded to, for example, the inner surface 13 of the glass plate 10 (or the fourth surface 162 of the inner glass plate 16) so that the imaging device 2 cannot be seen from the outside. ..

  Specifically, the sheet material 70 according to the present modification is formed in a trapezoidal frame shape, and heating lines (74, 75) are printed along the inside and outside of the frame, respectively. Then, terminals (72, 73) are provided at the end of each heating wire (74, 75), and an electric current is caused to flow through each heating wire (74, 75) through the terminals (72, 73). The heating wires (74, 75) are configured so that they can be heated.

  The sheet material 70 is bonded to the inner surface 13 of the glass plate 10 with its central opening aligned with the photographing window 113, for example. If the surface of the photographing window 113 becomes cloudy, the main light flux 60 may be prevented from entering the photographing device 2, which may interfere with photographing outside the vehicle by the photographing device 2. On the other hand, when the sheet material 70 is used, the heating wires (74, 75) are heated to prevent the photographing window 113 from being fogged (anti-fog effect). As a result, it is possible to prevent the surface of the photographing window 113 from becoming cloudy and obstructing photographing outside the vehicle by the photographing device 2.

  In the present modification, a part of the lower side portion of the sheet material 70 like this forms the blocking portion 71 that blocks the progress of the sub-light flux, similarly to the blocking layer 11. The sheet material 70 is made of, for example, a material such as a black sticker that blocks the incidence of visible light. In addition to this, for example, the blocking unit may be configured by a part of the bracket for mounting the imaging device 2.

<4.7>
Moreover, in the said embodiment and the said modification, each interruption | blocking part (114, 18) is formed on the surface of a glass plate. However, the blocking portion can be appropriately arranged at a position on the optical path of the sub-beam 61 on the glass plate and at a position that does not block the optical path of the main beam 60. Specifically, in the case where the blocking portion is not provided, on the optical path where the sub-light flux 61 travels, the light is blocked in a range from entering the glass plate 10 to being reflected by the inner surface 13 and before entering the optical path of the main light flux 60. The parts can be arranged.

<4.8>
In the case where the glass plate of the window glass is made of laminated glass in which the outer glass plate and the inner glass plate are bonded to each other through the intermediate film as in the above modification, the blocking portion is configured as a part of the intermediate film. can do.

  FIG. 13 illustrates a window glass 1D according to this modification. In FIG. 13, the blocking section 171 is configured as a part of the intermediate film 17. Such a blocking portion 171 can be formed, for example, by coloring a part of the intermediate film 17 with a pigment that hardly transmits light such as black. As the colorant for coloring such an intermediate film 17, for example, a plasticizer liquid in which a pigment is dispersed may be used. Further, as the plasticizer liquid, an adipic acid alkyl ester plasticizer, a phthalic acid ester plasticizer, or the like can be used.

<4.9>
Further, in the above-described embodiment, the image capturing device 2 includes the four lenses 211 to 214. However, the configuration of the imaging device 2 can be changed as appropriate according to the embodiment. For example, another form of the photographing device 2 can be illustrated by FIGS. 14 and 15.

  FIG. 14 illustrates the configuration of the image capturing apparatus 2A according to this modification. The image capturing apparatus 2A illustrated in FIG. 14 uses a lens system 26 having two plano-convex lenses (261, 262), an aperture stop 27 arranged on the object side from the lens system 26, and light passing through the lens system 26. An image sensor 28 for capturing an image. In this modification, the aperture stop 27 is arranged on the subject side (left side in FIG. 14) of the lens system 26.

  Therefore, in this case, since the position and size of the aperture stop 27 match the entrance pupil, the entrance pupil can be made to appear on the taking window 113 by providing the aperture stop 27 on the taking window 113. Therefore, in this case, the size of the photographing window 113 can be reduced to the size of the entrance pupil.

  Further, as illustrated in FIG. 15, a distortion correction plate 29 may be provided. FIG. 15 illustrates an imaging device 2B according to the modification. The photographing apparatus 2B has the same configuration as the photographing apparatus 2A except for the distortion correction plate 29. The distortion correction plate 29 can correct distortion caused by, for example, the inclination angle, thickness, radius of curvature, lens power, etc. of the glass plate 10 of the window glass 1. Such a distortion correction plate 29 can be configured to fit a window glass by appropriately processing a transparent plate member having a free curved surface, for example.

<4.10>
Further, in the above-described embodiment, the number of the photographing windows 113 provided in the shielding layer 11 is one, and the number of the photographing devices 2 installed in the vehicle is one. However, the number of imaging devices 2 installed in the vehicle may be two or more. That is, a stereo camera including a plurality of image capturing devices may be installed in the vehicle. Further, according to this, the number of the photographing windows 113 provided in the shielding layer 11 may be plural.

  FIG. 16 is a plan view illustrating a window glass 1E according to this modification. In addition, FIG. 17 illustrates an in-vehicle system 5A according to this modification. As illustrated in FIGS. 16 and 17, the stereo camera 20 may include two image capturing devices 2. At this time, these two image capturing devices 2 are arranged apart from each other so that two captured images with parallax can be acquired at the same time. Therefore, as illustrated in FIG. 16, the two photographing windows 113 provided in the shielding layer 11 of the window glass 1E are arranged apart from each other so that each photographing window 113 corresponds to each photographing device 2. .. At this time, two blocking parts 114 are also provided. Then, each blocking unit 114 is arranged below each photographing window 113 so that a double image is not generated in each photographing device 2.

  Further, the stereo camera 20 can simultaneously acquire two captured images with parallax. Therefore, the image processing device 3 (the image processing unit 321) that acquires the captured image from the stereo camera 20 analyzes the two captured images having the parallax to detect the position of the subject in the two captured images. Etc. may be calculated. As a result, the in-vehicle system 5A can acquire abundant information regarding the situation outside the vehicle as compared with the case where the outside of the vehicle is photographed by the single photographing device 2. The position of the subject can be calculated by a known stereo vision method. In addition to the position of the subject, that is, the distance between the subject and the vehicle, the image processing unit 321 acquires various information regarding the condition outside the vehicle from a plurality of captured images with parallax based on a known method. You may. For example, the image processing unit 321 can specify the moving speed of the subject by periodically calculating the position of the subject and referring to the traveling speed of the own vehicle.

  According to this modification, the stereo camera 20 can obtain a wealth of information regarding the situation outside the vehicle. However, if a double image occurs in the captured image, an error may occur in the parallax value between the plurality of captured images acquired by the stereo camera 20, and the accuracy of the position measurement of the subject may decrease. On the other hand, according to this modified example, it is possible to prevent a double image from being generated in the captured image by the blocking unit 114, and thus it is possible to prevent the accuracy of the position measurement of the subject from being lowered. You can The present technology that prevents a double image from being generated in a captured image captured by an image capturing apparatus installed in a vehicle by the blocking unit 114 that blocks the sub-beam 61 is a scene in which distance measurement is performed by such a stereo camera 20. , It is more effective in situations where the accuracy of the shot image is required.

<4.11>
Moreover, in the said embodiment, the glass plate 10 was shape | molded by the press molding method. However, the method of forming the glass plate 10 is not limited to such an example, and can be appropriately selected according to the embodiment. For example, the glass plate 10 may be formed by the self-weight bending method illustrated in FIG.

  FIG. 18 illustrates a glass plate forming apparatus according to the present modification. In this molding apparatus, first, a glass plate 10 having a shield layer 11 laminated on an inner surface 13 by screen printing or the like is prepared. Then, the glass plate 10 is placed on the ring-shaped (frame-shaped) mold 84.

  The forming die 84 is arranged on the carrying table 85, and the carrying table 85 sequentially passes through the heating furnace 86 and the annealing furnace 87 in a state where the glass plate 10 is placed on the forming die 84. At this time, since the molding die 84 has a ring shape, the glass plate 10 passes through the heating furnace 86 with only the peripheral edge thereof being supported. When the glass plate 10 is heated to a temperature near the softening point in the heating furnace 86, the glass plate 10 is curved downward due to its own weight inside the peripheral portion and curved.

<4.12>
Further, in the above embodiment, the shielding layer 11 has a single layer structure. However, the shielding layer 11 can have a multi-layer structure. For example, the first ceramic layer is formed by stacking ceramics on the inner surface 13 of the glass plate 10. Next, a silver layer is formed by laminating silver on the first ceramic layer. Further, a second ceramic layer is formed by laminating a ceramic on this silver layer. Thereby, the shield layer 11 having a three-layer structure can be formed. The shielding layer 11 having the three-layer structure can shield electromagnetic waves by the silver layer. In addition, the material having the composition shown in Table 2 below can be used for this silver layer.

* 1, Main component: Bismuth borosilicate, zinc borosilicate

  Examples of the present invention will be described below. However, the present invention is not limited to this embodiment.

<Distortion near the boundary between the shielding layer and the photographing window>
First, in order to investigate what kind of distortion occurs at the boundary between the area where the shielding layer is formed and the area where the shielding layer is not formed when the shielding layer is formed using ceramics, the following glass plate is used. Prepared.

(1) Structure of glass plate: The outer glass plate and the inner glass plate were made of green glass having a thickness of 2 mm, and a single-layer interlayer film was arranged between them to obtain a laminated glass.
(2) Shielding layer: A three-layered shielding layer was formed by disposing a silver layer having the composition shown in Table 2 between the first ceramic layer and the second ceramic layer having the composition shown in Table 1 above. In addition, a trapezoidal photographing window was formed on the shielding layer.
(3) Fabrication of glass plate: The first ceramic layer, the silver layer, and the second ceramic layer were screen-printed on the vehicle inner surface of the inner glass plate to form a shielding layer. Then, it was fired at 650 ° C. in a heating furnace with a molding die as shown in FIG. 8 to be molded into a curved surface, which was conveyed from the heating furnace and then gradually cooled.

  Subsequently, when the glass plate manufactured as described above was measured for the strain of the glass plate near the boundary of the shielding layer, the results shown in FIG. 19 were obtained. In the graph of FIG. 19, the horizontal axis represents the length of the glass plate in the surface direction, and the vertical axis represents the lens power (millimeter diopter). (Diopter) is the reciprocal of the focal length due to the lens action, and the unit is (1 / m).

  The method of measuring the lens power is as follows. First, light is projected on a glass plate in a dark room to form a shadow on the screen behind the glass plate. At this time, if there is a convex lens action on the glass plate, the light is condensed and the shadow on the screen becomes bright. On the other hand, the concave lens effect on the glass plate makes it dark.

  Here, there is a correlation between the lens power and the brightness of the shadow on the screen, and by placing a lens with a known lens power and measuring the brightness on the screen at that time, the relationship between the lens power and the brightness Can be obtained. Therefore, the lens power of the glass plate can be obtained by disposing the target glass plate and measuring the brightness on the screen over the entire surface of the glass.

  As a result of such a measurement, as shown in FIG. 19, the lens power sharply increases near the boundary from the shielding layer to the non-shielding region, and the distortion of the glass plate increases. Recognize. Then, it can be seen that the distortion is reduced when it is separated from the boundary by a predetermined length, and disappears when it is further separated.

  Further, in order to examine the deformation of the image due to the distortion of the glass plate, a perspective distortion test of JIS R3212 was performed on a glass plate having a trapezoidal photographing window formed in the shielding layer, and the scene was photographed. FIG. 20 shows the photograph thus obtained. As shown in FIG. 20, the true circle is deformed into an elliptical shape within 8 mm from the boundary between the shielding layer and the photographing window (distortion region). On the other hand, it can be seen that the vicinity of the center of the photographing window (the area excluding 8 mm from the boundary) is closer to a perfect circle than the vicinity of the boundary.

  Therefore, as described above, in order to prevent the image capturing range of the image capturing apparatus from including the above-described strained region having a large strain, for example, when the tilt angle φ of the window glass is 30 °, It is presumed that it is preferable to arrange a strain area having a width of 8 mm on the outside. In this case, the photographing window is configured to be larger than an ellipse having a major axis of 24 mm in the vertical direction and a minor axis of 20 mm in the horizontal direction.

<Relationship between the position of the entrance pupil and the amount of distortion>
Next, in order to investigate the relationship between the position of the entrance pupil and the distortion amount in the photographing window, an optical simulation as illustrated in FIG. 21 was performed. For this optical simulation, software OSLO Premium (Release 6.3) manufactured by Lambda Research, USA was used. The window glass is composed of one glass plate, and the thickness of the window glass is 4.8 mm. Further, the glass plate was inclined at 30 ° with respect to the horizontal direction, and the refractive index of the glass plate was 1.52. Furthermore, the outer and inner surfaces are biconic surfaces, the center of symmetry of the outer surface is on the line connecting the target center and the entrance pupil, and the radius of curvature R1x of the outer surface in the horizontal direction (X direction) is R1x. Was 4800 mm. The curvature radius R2y in the vertical direction (Y direction) of the inner surface of the vehicle was set to 1800 mm, and the horizontal curvature radius R2x of the inner surface of the vehicle was set to 4800 mm. The biconic surface is a curved surface whose position z in the optical axis direction (Z direction) satisfies the relational expression shown in the following Expression 7.

Cx is the curvature in the X direction (the reciprocal of the radius of curvature), and Cy is the curvature in the Y direction (the reciprocal of the radius of curvature).

  Here, the radius of curvature R1x in the vertical direction of the surface on the vehicle outer side was changed from 1600 mm to 2000 mm. Further, the optical distance (optical path length in terms of air layer) between the entrance pupil of the photographing device and the window glass (inner surface) was changed from -10 mm to 30 mm at intervals of 5 to 10 mm. Further, the measurement points shown in FIG. 21 were set on the target placed 1500 mm away from the window glass.

Then, the direction at the position of the entrance pupil of the ray (the chief ray) that originates from the measurement point and passes through the center of the entrance pupil is
(A) When a window glass is arranged (angle P)
(B) When no window glass is placed (angle Q)
Then, the distortion amount was calculated by the following equation 5.

This distortion amount is a numerical value that does not depend on the focal length and F value of the image capturing apparatus. The evaluated measurement points and directions were Ay (upward in the Y direction), Cy (downward in the Y direction), and Ex (leftward in the X direction) shown in FIG. As a result, the results shown in FIGS. 22A and 22B were obtained. The distance between the entrance pupil and the window glass being -10 mm means that the entrance pupil is away from the window glass (inner surface) by 10 mm in the optical path length outside the vehicle.

  FIG. 22A shows the distortion amount of the target photographed through the window glass when the distance between the entrance pupil of the camera and the window glass is changed from −10 mm to 30 mm, in the case of R1y = 1600, 1800, 2000 mm. It is a thing. According to this result, when the radius of curvature in the vertical direction outside the vehicle is set to 1800 mm, that is, when the outside surface of the window glass and the inside surface of the vehicle have the same radius of curvature, It was found that the variation of the distortion amount was small even if the distance between the entrance pupil and the window glass was varied.

  Further, in FIG. 22A, when the amount of distortion changes due to the change in the radius of curvature of the window glass, the change in the amount of distortion due to the change in the radius of curvature of the window glass is made by setting the distance D between the window glass and the entrance pupil to approximately 3 mm. It turns out that can suppress. That is, for example, when D was set to -10 mm, when the radius of curvature of the window glass was changed to 1600 mm to 2000 mm, the distortion amount of the target Cy was changed to 1.1% to 2.7%. On the other hand, when D was set to about 3 mm, the amount of distortion of the target Cy was 1.9% and hardly changed even when the curvature radius of the window glass was changed to 1600 mm to 2000 mm. With respect to the target Ay, the variation of the distortion amount becomes almost zero by setting D to about 6 mm. However, since the target Cy has a larger absolute amount of distortion and a larger amount of fluctuation, the change in the amount of distortion due to the fluctuation in the radius of curvature of the window glass can be suppressed by setting the distance D between the window glass and the entrance pupil to approximately 3 mm. I knew I could do it.

  Further, FIG. 22B shows the distortion amount of the target photographed through the window glass when the radius of curvature R1y in the vertical direction of the outer surface of the vehicle is changed from 1600 mm to 2000 mm at intervals of 100 mm. It shows the case where the distance D to the glass is -10, 0, 10, 30 mm. According to this result, Cy had the largest variation in the amount of distortion. Specifically, when the distance between the entrance pupil of the camera and the window glass is set to 30 mm, the distortion amount at the point Cy is 3.3 when the radius of curvature in the vertical direction of the vehicle exterior surface is 1600 mm and 2000 mm. There was about a 2.9% variation from% to 0.4%.

  On the other hand, when the distance between the entrance pupil of the camera and the window glass is set to 10 mm, the variation of the distortion amount at the point Cy is 2.3% when the radius of curvature of the outer surface of the vehicle in the vertical direction is 1600 mm and 2000 mm. It was possible to suppress from 1.5 to 1.5% to about 0.8%. Further, when the distance between the entrance pupil of the camera and the window glass is set to −10 mm, the variation of the distortion amount at the point Cy is 1.1 when the radius of curvature in the vertical direction of the vehicle exterior surface is 1600 mm and 2000 mm. % To 2.6%, and could be suppressed to about 1.5%.

  Therefore, by setting the distance between the entrance pupil of the camera and the window glass in the range of -10 mm to 10 mm, even if the vertical radius of curvature of the outer surface of the vehicle is changed, the target of the target imaged through the window glass It was found that the fluctuation of the distortion amount can be suppressed to some extent. In particular, by setting the distance between the entrance pupil of the camera and the window glass in the range of 2 mm to 3 mm, even if the vertical radius of curvature of the outer surface of the vehicle is changed, the distortion of the target photographed through the window glass is distorted. It was found that the fluctuation of the quantity can be almost suppressed.

  Here, the fluctuation of the radius of curvature in the vertical direction of the outer surface of the vehicle indicates the manufacturing error of the window glass, and the fluctuation of the distance between the window glass and the entrance pupil indicates the error when the camera is attached. That is, when the radius of curvature of the surface on the outside of the vehicle and the radius of curvature of the surface on the inside of the vehicle are the same, the lens effect hardly occurs on the window glass, so the distortion amount of the image captured through the window glass is , Even if the distance between the window glass and the camera fluctuates, the value remains almost constant. On the other hand, when the radius of curvature of the surface on the outer side of the vehicle and the radius of curvature of the surface on the inner side of the vehicle do not match due to variations in manufacturing, due to the mismatch, the lens effect is likely to occur in the window glass, and The amount of distortion of a captured image changes greatly when the distance between the window glass and the camera changes.

  Since the degree of inconsistency may fluctuate due to a manufacturing error, the amount of distortion of the image captured through the window glass may fluctuate due to the variation in the degree of disagreement. Then, the correction value for correcting the captured image taken through the window glass becomes a value unique to each window glass, and the correction value must be specified every time the window glass is manufactured. I will end up.

  On the other hand, according to the result of the above simulation, the radius of curvature of the surface outside the vehicle and the radius of curvature of the surface inside the vehicle are set by setting the distance between the entrance pupil of the camera and the window glass in the range of -10 mm to 10 mm. It was found that even if the degree of disagreement fluctuates, the fluctuation of the distortion amount of the image taken through the window glass can be suppressed to some extent. In particular, it has been found that by setting the distance between the entrance pupil of the camera and the window glass in the range of 2 mm to 3 mm, it is possible to substantially suppress the variation in the distortion amount of the image captured through the window glass. This prevents a large variation in the distortion amount of the image captured through each imaging window due to the manufacturing error of the windshield, and uniformly sets the correction value for correcting the captured image without considering individual differences. be able to.

<Transmittance and reflectance of the shielding layer>
Next, as shown in FIG. 23A, the following measurement was carried out in order to examine whether or not the black ceramics of the components shown in Table 1 above can be used as the antireflection member and the transmission prevention member. That is, as illustrated in FIG. 23A, the black ceramics having the components shown in Table 1 above were attached to the surface of the glass plate. Then, incident light is incident on the glass plate at an incident angle of 6 degrees from the side opposite to the surface on which the black ceramic is attached (hereinafter, also referred to as “black ceramic treated surface”), and is reflected on the surface on which the black ceramic is attached. The reflectance of each reflected light by wavelength was measured with a spectrophotometer (Shimadzu Corporation, model number: UV3100PC). In addition, even for a glass plate to which the black ceramic is not adhered, that is, the surface on which the above-mentioned black ceramic is not adhered (hereinafter, also referred to as “untreated surface”), the wavelength of the reflected light is similarly measured. Another reflectance was measured.

  FIG. 23B shows the measurement results of the reflectance of each glass plate. As shown in FIG. 23B, in the visible light wavelength region, the reflectance of the untreated surface was 4.3 to 4.5%, while the reflectance of the black ceramic treated surface was 1.4 to 1%. It was 0.5%. That is, the reflectance of the black ceramic treated surface was a very small value as compared with the reflectance of the untreated surface. From this, it was found that the shielding layer formed of black ceramic was effective as a blocking portion (antireflection member) on the inner surface.

  The transmittance of the black ceramic treated surface was measured by the following method. That is, as shown in FIG. 23A, incident light was made incident on a glass plate to which a black ceramic was attached under the same conditions as above. Then, the total light transmittance by wavelength of the transmitted light transmitted from the black ceramic treated surface was measured with an integrating sphere (manufactured by Shimadzu Corporation, model number: UV3100PC).

  FIG. 23C shows the measurement result of the total light transmittance for each wavelength. As shown in FIG. 23C, the transmittance of the black ceramic treated surface was 0.025% or less, which was an extremely small value. From this, it was found that the shielding layer formed of black ceramic was effective as a blocking portion (transmission preventing member) on the outer surface.

1 ... window glass,
10 ... glass plate,
11 ... Shielding layer, 111 ... Peripheral area, 112 ... Projection area, 113 ... Photographing window,
114 ... Blocking unit,
12 ... Non-shielding area, 13 ... Inner surface, 14 ... Outer surface,
15 ... Outer glass plate, 151 ... First surface, 152 ... Second surface,
16 ... inner glass plate, 161 ... third surface, 162 ... fourth surface,
17 ... Intermediate film, 171 ... Blocking part,
18 ... Shield,
2 ... Imaging device (camera), 201 ... Incident light,
21 ... Lens system, 211-214 ... Lens, 22 ... Aperture stop,
23 ... Image sensor, 24 ... Entrance pupil,
2A, 2B ... Imaging device (camera),
26 ... Lens system, 261, 262 ... Plano-convex lens, 27 ... Aperture stop,
28 ... Image sensor, 29 ... Distortion correction plate,
250 ... Imaging device (camera), 251 ... Lens, 252 ... Lens,
253 ... Aperture stop, 254 ... Image sensor, 255 ... Entrance pupil,
3 ... Image processing device,
31 ... Storage unit, 32 ... Control unit, 321 ... Image processing unit, 33 ... Input / output unit,
5 ... In-vehicle system,
60 ... Main light flux, 61 ... Sub light flux, 62 ... Arrow (direction of reflection of sub light flux),
80 ... Heating furnace, 81 ... Roller conveyor, 811 ... Roller,
82 ... Molding device, 821 ... Upper mold, 822 ... Lower mold,
84 ... Mold, 85 ... Transport platform, 86 ... Heating furnace, 87 ... Slow cooling furnace,
900 ... Imaging device, 901 ... Glass plate, 902 ... Main luminous flux, 903 ... Sub luminous flux

Claims (11)

A window glass used in a vehicle in which an imaging device can be arranged,
A glass plate arranged in an inclined posture,
A sub-light flux that is emitted from the same place as the main light flux that passes through the glass plate and enters the imaging device, and that can enter the vicinity of the optical path of the main light flux by being reflected in the glass plate. A blocking portion arranged at a position on the optical path of the glass plate of the sub-beam, and at a position that does not block the optical path of the main beam so as to block the progress of
Equipped with
The width of the blocking portion in the direction in which the sub-beam can shift when it is assumed that the sub-beam enters the glass plate and is reflected in the glass plate has a length L or more that satisfies the formula (1). And is not more than a length that does not overlap the driver's visual field range,
The cutoff portion is arranged such that the main light flux passes through the range of the length L from the cutoff portion in a direction in which the sublight flux may be shifted.
Window glass.
L = 2 × T × sin θ / (n ² −sin ² θ) ^0.5 (1)
In addition,
T is the thickness of the glass plate,
θ is the incident angle of the light ray traveling in the horizontal direction with respect to the glass plate,
n is the refractive index of the glass plate,
Show.   A window glass used in a vehicle in which an imaging device can be arranged,
  A glass plate arranged in an inclined posture,
  A sub-light flux that is emitted from the same place as the main light flux that passes through the glass plate and enters the imaging device, and that can enter the vicinity of the optical path of the main light flux by being reflected in the glass plate. A blocking portion arranged at a position on the optical path of the glass plate of the sub-beam, and at a position that does not block the optical path of the main beam so as to block the progress of
Equipped with
  Assuming that the sub-beam enters the glass plate and is reflected in the glass plate, the width of the cutoff portion in the direction in which the sub-beam may shift has a length L that satisfies Expression (2). ₀ The length is equal to or more than the length that does not overlap the driver's visual field range,
  The blocking unit extends from the blocking unit to the length L in a direction in which the sub-beam may shift. ₀ Is arranged so that the main light flux passes through the range of
Window glass.
  L ₀ = 0.347 × T ÷ (n ² -0.030) ^0.5   ... Formula (2)
  In addition,
  T is the thickness of the glass plate,
  n is the refractive index of the glass plate,
Show. The blocking unit is disposed on the vehicle outer side than the vehicle inner surface of the glass plate, is disposed on the vehicle inner surface of the glass plate and the transmission preventing member that prevents the transmission of the sub-beam, and Composed of at least one of antireflection members for preventing reflection,
The window glass according to claim 1 or 2 . A shielding layer provided on the glass plate for shielding a visual field from the outside of the vehicle, further comprising a shielding layer having a photographing window through which the main light flux can be transmitted so that the photographing device can photograph a situation outside the vehicle,
The blocking portion is configured by a part of the shielding layer,
The window glass according to any one of claims 1 to 3 . The area of the photographing window is 3000 mm ² or less,
The window glass according to claim 4 . The width of the blocking portion in the direction in which the sub-beam can shift when it is assumed that the sub-beam enters the glass plate and is reflected in the glass plate has a length L or more that satisfies the formula (1). And
The cutoff portion is arranged such that the main light flux passes through the range of the length L from the cutoff portion in a direction in which the sub-light flux may shift,
The width of the photographing window in the direction in which the sub-light flux can shift is formed to be the length L or more.
The window glass according to claim 5 .
L = 2 × T × sin θ / (n ² −sin ² θ) ^0.5 (1)
In addition,
T is the thickness of the glass plate,
θ is the incident angle of the light ray traveling in the horizontal direction with respect to the glass plate,
n is the refractive index of the glass plate,
Show. The width of the photographing window in the direction in which the sub-beam can shift when it is assumed that the sub-beam enters the glass plate and is reflected in the glass plate is formed so as to satisfy Expression (3). The
The window glass according to any one of claims 4 to 6 .
R ≦ H × cos θ Equation (3)
In addition,
R is the diameter of the entrance pupil in the optical system of the imaging device,
H is the width of the photographing window in the direction in which the sub-light flux can shift,
θ is the incident angle of the light ray traveling in the horizontal direction with respect to the glass plate,
Show. The window glass, Ru is used a stereo camera to the vehicle can be arranged with a plurality of imaging devices spaced apart from each other to obtain a plurality of images generated parallax,
The window glass according to any one of claims 1 to 7 . A vehicle system for mounting to a vehicle comprising a window glass as claimed in any one of claims 1 to 7,
An imaging device that captures the situation outside the vehicle,
An image processing device for processing an image acquired by the photographing device,
Equipped with
The optical system of the imaging device is configured such that the entrance pupil is located closer to the subject than the optical components.
In-vehicle system. The photographing device is arranged such that an optical distance between an entrance pupil in an optical system of the photographing device and a photographing window of the window glass is within 10 mm in an optical axis direction of the photographing device.
The in-vehicle system according to claim 9 . An in-vehicle system for mounting on a vehicle including the window glass according to claim 8 .
A stereo camera having a plurality of imaging devices separated from each other so as to obtain a plurality of images with parallax,
An image processing device that analyzes a plurality of images acquired by the stereo camera to calculate the position of a subject in the shooting range of the stereo camera,
With
In-vehicle system.