WO2016088472A1

WO2016088472A1 - Windshield and vehicle-mounted system

Info

Publication number: WO2016088472A1
Application number: PCT/JP2015/080117
Authority: WO
Inventors: 神吉　哲; 橘高　重雄
Original assignee: 日本板硝子株式会社
Priority date: 2014-12-04
Filing date: 2015-10-26
Publication date: 2016-06-09
Also published as: JP2016107755A

Abstract

Provided is a windshield that can be used in a vehicle-mounted system capable of acquiring sufficient information using a simple configuration. A windshield according to an aspect of the present invention is a windshield for an automobile in which a stereo camera including a plurality of mutually spaced-apart photography devices can be installed so as to enable acquisition of a plurality of images between which parallax arises, the windshield being provided with a glass plate and a shielding layer which is disposed on the glass plate and which shields a field of view from outside the vehicle. The shielding layer is provided with a plurality of photography windows corresponding respectively to the plurality of photography devices, to enable each of the plurality of photography devices of the stereo camera installed in the vehicle to capture images of the situation outside the vehicle.

Description

Windshield and in-vehicle system

The present invention relates to a windshield and an in-vehicle system.

Conventionally, some windshields for automobiles are provided with a shielding layer for blocking the field of view from the outside of the vehicle. This shielding layer is provided along the peripheral edge of the windshield so that the adhesive for attaching the windshield to the automobile cannot be seen from the outside of the vehicle.

In recent years, an in-vehicle system has been proposed in which a camera for photographing the situation outside the vehicle is installed in the vehicle. This in-vehicle system recognizes oncoming vehicles, preceding vehicles, pedestrians, traffic signs, lane boundaries, etc. by analyzing captured images of the subject acquired by the camera, and informs the driver of various dangers. Driving assistance can be provided. However, the camera of this in-vehicle system is often installed at a position where the shielding layer is included in the photographing range of the camera, such as in the vicinity of the support portion of the rearview mirror, and the shielding layer may hinder the photographing of the camera. is there.

Therefore,

Patent Documents

1 and 2 propose providing a transmission window in a part of the shielding layer. For example, by replacing a part of the intermediate film with a material having a high visible light transmittance, or by providing a region not laminated with ceramic, a region with a high visible light transmittance (transmission window) is provided on a part of the shielding layer. ) Can be formed. As a result, the camera installed in the vehicle can photograph the situation outside the vehicle without being blocked by the shielding layer.

JP 2006-327381 A JP 2007-039278 A

However, in

Patent Documents

1 and 2, since a single transmission window is provided in the windshield and a traffic situation outside the vehicle is photographed from the single transmission window using a single camera, The distance, the moving speed of the subject, etc. could not be measured only by information from the camera. Therefore, the conventional in-vehicle system is further equipped with different types of measuring devices such as millimeter wave radar and laser radar to measure the distance between the subject and the vehicle, the moving speed of the subject, etc. There is a problem that the system configuration becomes complicated as much as connecting the two.

The present invention has been made in view of such a situation in one aspect, and an object thereof is to provide a windshield applicable to an in-vehicle system capable of acquiring sufficient information with a simple configuration.

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

In other words, a windshield according to one aspect of the present invention is a windshield for an automobile in which a stereo camera having a plurality of imaging devices spaced apart from each other can be obtained so that a plurality of images with parallax can be acquired. And a shielding layer that is provided on the glass plate and shields the field of view from the outside of the vehicle. The shielding layer includes a plurality of photographing windows respectively corresponding to the plurality of photographing devices so that each of the plurality of photographing devices of the stereo camera arranged in the vehicle can photograph a situation outside the vehicle.

In the windshield according to the configuration, the shielding layer provided on the glass plate includes a plurality of photographing devices corresponding to the photographing devices so that each photographing device of the stereo camera arranged in the vehicle can photograph the situation outside the vehicle. Has a window. Therefore, the windshield according to the present invention can be applied to a stereo camera that can measure the distance to the subject by parallax generated between a plurality of images. Therefore, according to the configuration, it is possible to acquire information such as the distance to the subject without connecting different types of data with the stereo camera, and thus it is possible to acquire sufficient information with a simple configuration. A windshield applicable to an in-vehicle system can be provided. By analyzing the captured image of the subject acquired by the stereo camera, it recognizes oncoming vehicles, preceding vehicles, pedestrians, traffic signs, lane boundaries, etc., and supports various driving such as notifying the driver of danger. It is of course possible to do this. However, the present invention does not exclude the provision of different types of measuring devices such as millimeter wave radars and laser radars that do not have advanced image analysis functions such as subject recognition as described above.

As another form of the windshield according to the above configuration, the shielding layer may be configured by laminating a ceramic having a thermal expansion coefficient different from that of the glass plate on the inner surface of the glass plate. A strain region in which the glass plate is distorted at a peripheral portion of the shielding layer due to a difference in coefficient of thermal expansion between the glass plate and the ceramic, and a visual field range in which a driver driving the automobile confirms traffic conditions when driving , May be arranged so as not to overlap.

When the shielding layer is made of a ceramic having a different thermal expansion coefficient from that of the glass plate, due to the difference in thermal expansion coefficient between the glass plate and the ceramic, the glass plate is formed on the periphery of the shielding layer when forming the windshield. A strain region having a large strain is formed. The width of the strain region is about 8 mm.

Therefore, in this embodiment, the shielding layer is arranged so that the strain region of the glass plate and the visual field range of the driver do not overlap. As a result, an automobile equipped with this windshield can provide a driver with a good field of view during driving.

The field of view for confirming the traffic situation when the driver driving the car is the range that the driver in the driver's seat is careful when driving, and can be set as appropriate according to the embodiment. is there. For example, you may employ | adopt the test area | region A prescribed | regulated to JIS (R) 3212 (1998, "the safety glass test method for motor vehicles") as this visual field range.

Further, as another form of the windshield according to the above configuration, the glass plate is a laminated glass in which an outer glass plate arranged on the vehicle outer side and an inner glass plate arranged on the vehicle inner side are bonded to each other through an intermediate film. It may be constituted by. And the said shielding layer may be comprised by laminating | stacking the ceramic which has a different thermal expansion coefficient from the said inner side glass plate on the surface inside the vehicle of the said inner side glass plate. According to this configuration, it is possible to provide a photographing window with less distortion by forming a ceramic layer on the inner glass plate. Further, according to this configuration, it is possible to reduce the occurrence of an optical defect in the photographing window, so that it is possible to accurately measure the distance between the subject and the own vehicle.

Further, as another form of the windshield according to the above configuration, the glass plate is a laminated glass in which an outer glass plate arranged on the vehicle outer side and an inner glass plate arranged on the vehicle inner side are bonded to each other through an intermediate film. It may be constituted by. And the said shielding layer laminates | stacks the ceramic which has a thermal expansion coefficient different from the said outer side glass plate and the said inner side glass plate on the inner surface of the said outer side glass plate and the inner surface of the said inner side glass plate, respectively. It may be constituted by.

According to this configuration, the shielding layer is formed by providing the ceramic layer on each of the inner surface of the outer glass plate and the inner surface of the inner glass plate. Therefore, a two-layer shielding layer can be formed, and the appearance can be improved.

Also, there are cases where wires, antennas, etc. are embedded in the intermediate film. In this case, by providing a ceramic layer on each of the inner surface of the outer glass plate and the inner surface of the inner glass plate, these can be hidden from the outer side and the inner side of the vehicle. Therefore, even in such a case, the appearance on the outer ring can be improved.

Further, as another form of the windshield according to the above configuration, each of the plurality of photographing windows may be formed such that the vertical and horizontal widths of the plurality of photographing windows satisfy Expression (1).

Note that H represents the vertical and horizontal widths of the imaging window. a shows the width | variety of the distortion area | region in the peripheral part of an imaging | photography window. b indicates the diameter of the entrance pupil. c shows an attachment error.

When the plate glass is heat-treated at the boundary between the laminated region of the ceramic having a different coefficient of thermal expansion from the glass plate and the non-laminated region of the ceramic, in other words, at the boundary between the photographing window and the shielding layer. Due to the difference in thermal expansion coefficient, optical defects due to strain are likely to be formed (strain region). As will be described later, the width a of the strain region is formed in a range of about 8 mm from the boundary between the photographing window and the shielding layer. The diameter b of the entrance pupil is 4 mm in the case of a camera (imaging device) having a focal length f = 8 mm and an aperture ratio F = 2. Furthermore, the mounting error c is about 5 mm. Therefore, in the case of the above conditions, the vertical and horizontal widths of each photographing window are configured to be 25 mm or less. Thus, according to this configuration, it is possible to make the size of each imaging window relatively small while avoiding the influence of distortion on each imaging device.

Also, a heater may be installed around each shooting window to prevent condensation on each shooting window. In this case, in the central region of each photographing window, there is a problem that dew condensation tends to remain due to being far from the heater installed around each photographing window. On the other hand, according to the configuration, since the size of each photographing window can be formed relatively small, it is possible to prevent dew condensation from easily remaining in the central region of each photographing window, and in the heater. Power consumption can be reduced.

Further, as another form of the windshield according to the above configuration, each of the plurality of photographing windows may be formed such that the vertical and horizontal widths of the plurality of photographing windows satisfy Expression (2).

The entrance pupil is an image when the aperture stop of the optical system constituting the photographing apparatus is viewed from the subject side, and corresponds to an “entrance” of light used in the optical system. In the case of a camera lens having a focal length f and an aperture ratio F, the diameter of the entrance pupil is (f / F). Therefore, in order not to block the light beam required by the photographing apparatus, the diameter of the photographing window is required to be a minimum (f / F + 2D · tanφ). However, D is the distance between the imaging window and the entrance pupil, φ is the field of view (half angle) of the imaging apparatus, and the imaging window is perpendicular to the optical axis of the imaging apparatus. Therefore, the minimum size of the imaging window is (f / F) when D = 0, that is, the diameter of the entrance pupil. As a result, since a guideline for the size of each photographing window is determined, the size of each photographing window can be determined relatively freely.

An in-vehicle system according to an aspect of the present invention is an in-vehicle system for mounting on an automobile including the windshield according to any one of the above aspects, and is separated from each other so that a plurality of images with parallax can be acquired. A stereo camera having a plurality of photographing devices, and an image processing device that analyzes a plurality of images acquired by the stereo camera and calculates a position of a subject appearing in a photographing range of the stereo camera. The image processing apparatus holds correction data for correcting an image deformed by the windshield, the correction data having a deformation amount determined according to the surface on which the ceramics are laminated, and the correction data Is used to execute correction processing for each image.

The present inventors have found that when the shielding layer is formed of a ceramic having a different coefficient of thermal expansion from that of the glass plate, the lens power of the photographing window varies depending on the surface of the ceramic laminated glass plate. Therefore, in this configuration, the image processing apparatus executes correction processing for each image using correction data in which the amount of deformation is determined according to the surface on which the ceramics are stacked. As a result, it is possible to realize an image correction process suitable for the photographing window provided in the windshield.

An in-vehicle system according to an aspect of the present invention is an in-vehicle system for mounting on an automobile including the windshield according to any one of the above aspects, and is separated from each other so that a plurality of images with parallax can be acquired. A stereo camera having a plurality of photographing devices, and an image processing device that analyzes a plurality of images acquired by the stereo camera and calculates a position of a subject that appears in the photographing range of the stereo camera. Good. The optical system in each of the plurality of photographing devices of the stereo camera may be configured such that the entrance pupil exists on the subject side with respect to the optical component. According to this configuration, since the entrance pupil of each photographing apparatus exists on the subject side of the optical component, it can be arranged on or near the windshield. Therefore, the incident light area on the windshield that enters the stereo camera can be reduced, and the size of each imaging window corresponding to each imaging apparatus can be reduced. This also makes it less likely to be affected by distortion on each shooting window.

As another form of the mounting system according to the above-described configuration, the stereo camera is configured such that, in the optical axis direction of each of the plurality of imaging devices, the entrance pupil of the optical system and the plurality of windshields in each of the plurality of imaging devices. It may be arranged so that the distance from each of the imaging windows is within a range of 10 mm or less. The present inventors arrange a stereo camera so that the distance between the entrance pupil of the lens constituting each photographing apparatus and each photographing window of the windshield is within 10 mm in the front and rear direction in the optical axis direction of each photographing apparatus. Thus, it has been found that the amount of deformation due to distortion of an image taken through the shooting window is less likely to fluctuate. Therefore, according to this configuration, it is possible to prevent the amount of distortion of the image captured through each imaging window from fluctuating greatly due to a manufacturing error of the windshield, and to correct the captured image without considering individual differences. The value can be set uniformly.

According to the present invention, it is possible to provide a windshield applicable to an in-vehicle system capable of acquiring sufficient information with a simple configuration.

FIG. 1 is a plan view illustrating a windshield according to an embodiment. FIG. 2 is a cross-sectional view illustrating a windshield according to the embodiment. FIG. 3A illustrates the relationship between the shooting window of the windshield and the shooting range of the shooting device according to the embodiment. FIG. 3B illustrates the relationship between the imaging window of the windshield and the entrance pupil of the imaging apparatus according to the embodiment. FIG. 4A illustrates the imaging device according to the embodiment. FIG. 4B illustrates an imaging apparatus in which the entrance pupil exists inside the lens system. FIG. 5 illustrates an in-vehicle system according to the embodiment. FIG. 6 illustrates the manufacturing process of the glass plate of the windshield according to the embodiment. FIG. 7 is a cross-sectional view illustrating a windshield according to another embodiment. FIG. 8 illustrates a photographing apparatus according to another embodiment. FIG. 9 illustrates a photographing apparatus according to another embodiment. FIG. 10 shows an example of a method for manufacturing a windshield according to another embodiment. FIG. 11 illustrates a shooting window according to another embodiment. FIG. 12 is a graph showing the distortion of the glass plate. FIG. 13 is a photograph showing the distortion of the glass plate. FIG. 14A is a graph showing the relationship between the surface on which the shielding layer is provided and the lens power of the left imaging window. FIG. 14B is a graph showing the relationship between the surface on which the shielding layer is provided and the lens power of the right imaging window. FIG. 15 illustrates a scene in which the amount of image distortion due to the windshield is simulated. FIG. 16 is a graph showing the amount of image distortion when the distance between the windshield and the entrance pupil is varied. FIG. 17 is a graph showing the amount of image distortion when the radius of curvature of the surface on the subject side is varied.

Hereinafter, an embodiment according to one aspect of the present invention (hereinafter also referred to as “this embodiment”) will be described with reference to the drawings. However, this embodiment described below is only an illustration 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 adopted as appropriate.

§1 Configuration Example First, the windshield 1 according to this embodiment will be described with reference to FIGS. 1 and 2. FIG. 1 is a plan view schematically illustrating a windshield 1 according to this embodiment. FIG. 2 is a cross-sectional view schematically illustrating the windshield 1 according to this embodiment. For convenience of explanation, the up and down direction in FIGS. 1 and 2 is referred to as “up and down”, the left and right direction in FIG. 1 is referred to as “left and right”, and the left and right direction in FIG.

As illustrated in FIGS. 1 and 2, the windshield 1 according to this embodiment includes a substantially trapezoidal glass plate and is attached to an automobile by being inclined from the vertical. This glass plate is composed of a laminated glass in which an outer glass plate 13 disposed on the outer side of the vehicle and an inner glass plate 14 disposed on the inner side of the vehicle are bonded to each other via a resin intermediate film 15.

The inner glass plate 14 constituting the laminated glass is provided with a shielding layer 11 that shields the field of view from the outside of the vehicle, and the stereo camera 2 is mounted inside the vehicle so as to be shielded by the shielding layer 11. The stereo camera 2 has two photographing devices (21A, 21B) separated from each other so that two images with parallax can be simultaneously acquired. Correspondingly, the shielding layer 11 has two imaging devices (21A, 21B) corresponding to the imaging devices (21A, 21B) so that the imaging devices (21A, 21B) arranged inside the vehicle can capture the situation outside the vehicle. Shooting windows (113A, 113B) are formed.

Further, the stereo camera 2 is connected to the image processing device 3 and constitutes an in-vehicle system 5 that can analyze the distance between the subject and the own vehicle based on a plurality of images acquired by the stereo camera 2. Hereinafter, each component will be described. For convenience of explanation, the vehicle outer surface of the outer glass plate 13 is referred to as “first surface”, the vehicle inner surface of the outer glass plate 13 is referred to as “second surface”, and the inner glass plate 14 is described below. A surface outside the vehicle may be referred to as a “third surface”, and a surface inside the vehicle of the inner glass plate 14 may be referred to as a “fourth surface”.

<Glass plate>
Depending on the embodiment, the glass plate constituting the windshield 1 can have various configurations. In the present embodiment, as illustrated in FIG. 2, the glass plate of the windshield 1 is composed of laminated glass in which an outer glass plate 13 and an inner glass plate 14 are bonded to each other via an intermediate film 15. This laminated glass is manufactured by a manufacturing method to be described later, so that it is formed in a curved shape from the peripheral part to the central part. Each of the outer glass plate 13 and the inner glass plate 14 constituting such a laminated glass can be a known glass plate, and can also be formed of heat ray absorbing glass, clear glass, green glass, UV green glass, or the like. .

However, the outer glass plate 13 and the inner glass plate 14 are each configured to realize visible light transmittance in accordance with the safety standards of the country where the automobile is used. For example, a desired solar radiation absorptivity can be secured by the outer glass plate 13, and the visible light transmittance can be adjusted by the inner glass plate 14 so as to satisfy safety standards. Below, as an example of the composition of the glass which can comprise the outer side glass plate 13 and the inner side glass plate 14, an example of a composition of a clear glass and an example of a heat ray absorption glass composition are shown.

(Clear glass)
SiO ₂ : 70 to 73% by mass
Al ₂ O ₃ : 0.6 to 2.4% by mass
CaO: 7 to 12% by mass
MgO: 1.0 to 4.5% by mass
R ₂ O: 13 to 15% by mass (R is an alkali metal)
Total iron oxide converted to Fe ₂ O ₃ (T-Fe ₂ O ₃ ): 0.08 to 0.14% by mass

(Heat ray absorbing 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 The ratio of ₂ is 0 to 2% by mass, the ratio of TiO ₂ is 0 to 0.5% by mass, and the glass skeleton components (mainly SiO ₂ and Al ₂ O ₃ ) are T-Fe ₂ O ₃ , CeO. _The composition can be reduced by an increase of ₂ and TiO ₂ .

The thickness of the laminated glass according to this embodiment is not particularly limited, but from the viewpoint of weight reduction, the total thickness of the outer glass plate 13 and the inner glass plate 14 is preferably 2.4 to 4.6 mm, More preferably, the thickness is 2.6 to 3.8 mm, and particularly preferably 2.7 to 3.2 mm. Thus, what is necessary is just to make the total thickness of the outer side glass plate 13 and the inner side glass plate 14 small for weight reduction. Although the thickness of each of the outer glass plate 13 and the inner glass plate 14 is not particularly limited, for example, the thickness of each of the outer glass plate 13 and the inner glass plate 14 can be determined as follows.

That is, the outer glass plate 13 is mainly required to have durability and impact resistance against impacts of flying objects such as pebbles. On the other hand, as the thickness of the outer glass plate 13 is increased, the weight increases, which is not preferable. In this respect, the thickness of the outer glass plate 13 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.

Moreover, although the thickness of the inner side glass plate 14 can be made equal to the thickness of the outer side glass plate 13, for example, thickness can be made smaller than the outer side glass plate 13 for weight reduction of a laminated glass. Specifically, considering the strength of the glass, the thickness of the inner glass plate 14 is preferably 0.6 to 2.0 mm, more preferably 0.8 to 1.6 mm, It is particularly preferable that the thickness is ˜1.4 mm. Furthermore, the thickness of the inner glass plate 14 is preferably 0.8 to 1.3 mm. Which thickness is used for the inner glass plate 14 can be appropriately determined according to the embodiment.

<Intermediate film>
Next, the intermediate film 15 that joins the outer glass plate 13 and the inner glass plate 14 will be described. The intermediate film 15 can have various configurations according to the embodiment. For example, the intermediate film 15 can have a three-layer structure in which a soft core layer is sandwiched between a pair of harder outer layers. In this way, the damage resistance performance and sound insulation performance of the windshield 1 can be improved by configuring the intermediate film 15 with a plurality of layers of a soft layer and a hard layer.

The material of the intermediate film 15 is not particularly limited, and can be appropriately selected according to the embodiment. For example, when the intermediate film 15 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. Since this polyvinyl butyral resin (PVB) is excellent in adhesiveness and penetration resistance with each glass plate (13, 14), it is preferable as a material for the outer layer. 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 the starting polyvinyl alcohol, (b) the degree of acetalization, (c) the type of plasticizer, (d) the addition ratio of the plasticizer, etc. Can be controlled. Therefore, a hard polyvinyl acetal resin used for the outer layer and a soft polyvinyl acetal resin used for the core layer may be produced by appropriately adjusting at least one of the conditions (a) to (d).

Furthermore, the hardness of the polyvinyl acetal resin can be controlled by the type of aldehyde used for acetalization, coacetalization with a plurality of types of aldehydes or pure acetalization with a single aldehyde. Although it cannot generally be said, the polyvinyl acetal resin obtained by using an aldehyde having a large number of carbon atoms tends to be softer. 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- Octyl aldehyde) can be used as a polyvinyl acetal resin obtained by acetalization with polyvinyl alcohol.

The total thickness of the intermediate film 15 can be appropriately set according to the embodiment, and can be set to, for example, 0.3 to 6.0 mm, preferably 0.5 to 4.0 mm. More preferably, it is 0.6 to 2.0 mm. For example, when the intermediate film 15 is configured with a three-layer structure of 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, 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.

The method for producing the intermediate film 15 is not particularly limited. For example, after blending a resin component such as the above-described polyvinyl acetal resin, a plasticizer, and other additives as necessary, and kneading uniformly, Examples thereof include a method of extruding each layer at once, and a method of laminating two or more resin films prepared by this method by a press method, a laminating method, or the like. The resin film before lamination used in a method of laminating by a press method, a laminating method or the like may have a single layer structure or a multilayer structure. Further, the intermediate film 15 can be formed of a single layer in addition to the above-described plural layers.

<Shielding layer>
Next, the shielding layer 11 provided on the glass plate of the windshield 1 will be described. As illustrated in FIG. 1, in this embodiment, a shielding layer 11 is formed on the peripheral edge of the windshield 1. Specifically, as illustrated in FIG. 2, the shielding layer 11 is laminated on the inner surface (fourth surface) of the inner glass plate 14.

The material of the shielding layer 11 may be appropriately selected according to the embodiment as long as the field of view from the outside of the vehicle can be shielded. For example, a dark color ceramic such as black, brown, gray, or dark blue is used. Also good. In this case, black ceramic is laminated on the inner surface of the inner glass plate 14 by screen printing or the like, and the laminated ceramic together with the inner glass plate 14 is heated. Thereby, the shielding layer 11 can be formed on the peripheral edge of the windshield 1. Various materials can be used for the ceramic used for the shielding layer 11. For example, a ceramic having the following composition can be used for the shielding layer 11.

* 1, Main component: Copper oxide, Chromium oxide, Iron oxide and Manganese oxide * 2, Main component: Bismuth borosilicate, Zinc borosilicate

As illustrated in FIG. 1, the shielding layer 11 according to this embodiment includes a peripheral region 111 along the peripheral portion of the windshield 1 and a protruding region 112 that protrudes downward in a rectangular shape from the upper side portion of the windshield 1. Can be divided. The peripheral region 111 shields light incident from the peripheral portion of the windshield 1. On the other hand, the protruding region 112 prevents the stereo camera 2 arranged in the vehicle from being seen from outside the vehicle.

However, if the shielding layer 11 blocks the photographing range of each photographing device (21A, 21B) of the stereo camera 2, the stereo camera 2 cannot photograph the situation in front of the vehicle. Therefore, in the present embodiment, the projecting region 112 of the shielding layer 11 has two areas corresponding to each imaging device (21A, 21B) so that each imaging device (21A, 21B) can capture the situation outside the vehicle. Substantially trapezoidal imaging windows (113A, 113B) are provided. Specifically, the photographing windows (113A, 113B) are regions that are spaced apart in the left-right direction and are not laminated with ceramic. That is, when screen-printing ceramic on the fourth surface, two shooting windows (113A, 113B) can be formed by providing two areas in the protruding area 112 where the ceramic is not printed.

Here, the size of each photographing window (113A, 113B) will be described with reference to FIGS. 3A and 3B. FIG. 3A illustrates the relationship between each imaging window (113A, 113B) provided in the shielding layer 11 and the imaging range of each imaging device (21A, 21B). FIG. 3B illustrates the relationship between each imaging window (113A, 113B) provided in the shielding layer 11 and the entrance pupil of each imaging device (21A, 21B).

As shown in FIG. 6 described later, the windshield 1 (laminated glass) according to this embodiment is heated at about 650 degrees in the shaping process. At that time, since the ceramic as the material of the shielding layer 11 is a dark color such as black, the amount of heat absorbed is smaller than that of a region where the ceramics are not stacked, for example, the region of each imaging window (113A, 113B). Become more. In addition, since the ceramic that is the material of the shielding layer 11 has a thermal expansion coefficient different from that of the inner glass plate 14, in the region where the shielding layer 11 is formed, compressive stress and tensile stress are generated during the shaping process. When the curvatures of the glass surfaces of the outer glass plate 13 and the inner glass plate 14 are different, the boundary between the inner glass plate 14 and the shielding layer 11 is likely to be distorted. Therefore, distortion is likely to occur also in the peripheral portion of each photographing window (113A, 113B) that is a boundary between the inner glass plate 14 and the shielding layer 11.

This distortion is formed in a range of about 8 mm from the peripheral edge of each photographing window (113A, 113B) according to an embodiment to be described later (corresponding to the width a of the distortion area in Equation 1 above). For this reason, as illustrated in FIG. 3A, in the vertical direction and the horizontal direction, the respective shooting windows (113A, 113B) are arranged so that regions each having a width of 8 mm are arranged on both sides of the shooting range of each shooting device (21A, 21B). ) Can be avoided the influence of the distortion on the captured image.

On the other hand, the larger the photographing windows (113A, 113B), the more the influence of the distortion can be avoided, but the area of the shielding layer 11 becomes smaller, and the shielding property of the visual field from the outside of the vehicle is impaired. Therefore, in order to prevent the captured image of each imaging device (21A, 21B) from being deformed while ensuring the shielding of the visual field by the shielding layer 11, the vertical direction of each imaging window (113A, 113B) and It is preferable that the width in the horizontal direction satisfy the above formula (1). As described above, the width a of the strain region is formed in a range of about 8 mm from the boundary between the imaging window and the shielding layer. When each photographing apparatus (21A, 21B) is configured by a camera having a focal length f = 8 mm and an aperture ratio F = 2, the diameter b of the entrance pupil is 4 mm. Furthermore, it is assumed that the attachment error c is set to about 5 mm. In such a case, it is preferable that the vertical and horizontal widths of the photographing windows (113A, 113B) are 25 mm or less.

In addition, the laminated glass which comprises the windshield 1 inclines from a perpendicular direction, and is attached to a motor vehicle. Therefore, the vicinity of the upper side of the windshield 1 is closer to each imaging device (21A, 21B), and the vicinity of the lower side of the windshield 1 is farther from each imaging device (21A, 21B). Therefore, in FIG. 3A, the width of the upper side approaching each imaging device (21A, 21B) is reduced in the imaging range of each imaging device (21A, 21B), and the width of the lower side away from each imaging device (21A, 21B) is It becomes trapezoid shape by becoming long.

Basically, the closer the respective photographing devices (21A, 21B) are to the respective photographing windows (113A, 113B), the smaller the photographing range on each photographing window (113A, 113B). Specifically, when the stereo camera 2 is arranged so that an entrance pupil of an optical system constituting the stereo camera 2 to be described later is positioned on each shooting window (113A, 113B), each shooting window (113A, 113B). The size of the light beam that passes through is the smallest.

Therefore, as illustrated in FIG. 3B, each shooting window (113A, 113B) is formed so that the vertical and horizontal widths of each shooting window (113A, 113B) satisfy the above formula (2). Good. When each photographing apparatus (21A, 21B) is configured with a camera having a focal length f = 8 mm and an aperture ratio F = 2, the vertical width and the horizontal width of each photographing window (113A, 113B) are 4 mm or more. Formed to be.

Further, for example, the diameter of the entrance pupil is 4 mm, the total angle of view of the photographing apparatus is 30 °, and the distance between the entrance pupil and the windshield is Dmm. In this case, the diameter F of the photographing window that is required because the photographing of the photographing apparatus is not hindered by the shielding layer can be expressed by the above formula 3.

Thereby, it is possible to secure the minimum size of each photographing window (113A, 113B) in which each photographing device (21A, 21B) can photograph the outside of the vehicle without being obstructed by the shielding layer 11. In addition, as a result, a guideline for the size of each photographing window (113A, 113B) is determined, so that the size of each photographing window (113A, 113B) can be determined relatively freely. .

In this embodiment, the visual field range 60 in which the driver confirms the traffic situation when driving the vehicle is arranged so as not to overlap the distortion region. The visual field range 60 is a range that a driver on the driver's seat pays attention when driving, and can be set as appropriate according to the embodiment. For example, the test area A defined in the appendix “Test Area for Optical Properties and Light Resistance of Safety Glass” of JIS R3212 (1998, “Safety Glass Test Method for Automobiles”) is adopted as this field of view. May be. As a result, the vehicle equipped with the windshield 1 can provide the driver with a good field of view during driving.

And each imaging | photography window (113A, 113B) may be arrange | positioned outside the visual field range 60 in which a driver | operator confirms a traffic condition, when driving a motor vehicle. This prevents the stereo camera 2 mounted on the automobile from blocking the driver's field of view, and provides the driver with a good field of view during driving.

In addition, each photographing window (113A, 113B) is configured so that the visible light transmittance in each photographing window (113A, 113B) is 70% or more as defined in JIS R 3211, for example. In addition, this transmittance | permeability can be measured by the spectroscopic method prescribed | regulated to JISＪZ 8722 as prescribed in JIS R 3212 (3.11 visible light transmittance test).

Further, a heater for preventing the condensation of each of the photographing windows (113A, 113B) may be installed around each of the photographing windows (113A, 113B). With this heater, condensation in each photographing window (113A, 113B) can be prevented, and the field of view of each photographing device (21A, 21B) can be kept in a good state. However, in this case, in the central region of each photographing window (113A, 113B), there is a possibility that condensation is likely to remain due to being far from the heater installed around each photographing window (113A, 113B). On the other hand, according to the configuration, since the size of each photographing window (113A, 113B) can be formed to be relatively small, condensation is likely to remain in the central region of each photographing window (113A, 113B). Can be prevented. In addition, since the amount of heat for preventing condensation is small, power consumption in the heater can be suppressed.

Further, in the windshield 1, a region on the inner side in the plane direction from the shielding layer 11 is a non-shielding region 12 where the shielding layer 11 is not formed. The driver and a companion sitting in the passenger seat check the traffic situation outside the vehicle through the non-shielding area 12. Therefore, the non-shielding region 12 of the windshield 1 is configured to have a visible light transmittance so that at least traffic conditions outside the vehicle can be visually observed.

<Stereo camera>
Next, the configuration of each imaging device (21A, 21B) of the stereo camera 2 will be described with reference to FIGS. 4A and 4B. FIG. 4A shows an example of the configuration of each imaging device (21A, 21B) of the stereo camera 2 according to the present embodiment. FIG. 4B shows an example of a camera in which the entrance pupil exists inside the lens system (optical system). Each photographing apparatus (21A, 21B) according to the present embodiment includes a lens system 22 having four lenses 221 to 224, an aperture stop 23 disposed between the third lens 223 and the fourth lens 224, and a lens. And an image sensor 24 that captures an image using light that has passed through the system 22.

In the present embodiment, the lenses 221 to 223 on the subject side (left side in FIG. 4A) with respect to the aperture stop 23 are configured so that the entrance pupil, which is a real image of the aperture stop 23, is located on the subject side with respect to the lens system 22. Is done. As shown in FIG. 4B, in a general camera lens, the position of the entrance pupil is inside the lens system. Therefore, it is difficult to set the distance between the entrance pupil and the windshield 1 to a certain value or less. On the other hand, according to the present embodiment, since the entrance pupil is located closer to the subject side than the lens system 22, the distance between the entrance pupil and the windshield 1 can be reduced, and is set to zero or a negative value. It is also possible to set.

The aperture stop 23 defines the thickness of the light beam incident on the image sensor 24. The size of the diameter of the aperture stop 23 may be configured to be changeable. For example, when each imaging device (21A, 21B) is configured as a camera having a focal length f = 8 mm and an aperture ratio F = 2, the diameter of the entrance pupil is 4 mm.

The image sensor 24 images a subject by forming an image of light that has passed through the lens system 22 on a light receiving plane. The image sensor 24 is an image pickup device constituted by, for example, a CCD. However, the type of the image sensor 24 is not limited to the CCD, and may be appropriately selected according to the embodiment. The stereo camera 2 can simultaneously acquire a plurality of images with parallax using each of the imaging devices (21A, 21B).

Such a stereo camera 2 is 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 stereo camera 2 is disposed in the vicinity of the support portion of the rearview mirror symmetrically about the rearview mirror as the target axis.

Here, as will be described later, in the optical axis direction of each imaging device (21A, 21B), the inventors of the present invention each of the entrance pupil of the lens system 22 constituting each imaging device (21A, 21B) and each of the windshield 1 By disposing the stereo camera 2 so that the distance from the shooting window (113A, 113B) is within 10 mm before and after, the amount of distortion of the image shot through each shooting window (113A, 113B) is unlikely to fluctuate. I found out. Therefore, in this embodiment, in the optical axis direction of each imaging device (21A, 21B), the entrance pupil of the lens system 22 constituting each imaging device (21A, 21B) and each imaging window (113A, 113B) of the windshield 1 are used. The stereo camera 2 is arranged so that the distance to the front and rear is within 10 mm. As a result, it is possible to prevent the amount of distortion of the image photographed through each photographing window (113A, 113B) from fluctuating greatly due to a manufacturing error of the windshield 1, and without considering individual differences of the windshield 1. The correction values of the correction data 311 can be determined uniformly.

<In-vehicle system>
Next, the in-vehicle system 5 constituted by the stereo camera 2 and the image processing device 3 will be described with reference to FIG. FIG. 5 illustrates the configuration of the in-vehicle system 5. As illustrated in FIG. 5, the in-vehicle system 5 according to the present embodiment includes the stereo camera 2 and an image processing device 3 connected to the stereo camera 2. As described above, the stereo camera 2 acquires a plurality of images with parallax.

The image processing device 3 is a device that analyzes a plurality of images acquired by the stereo camera 2 and analyzes the distance between the subject and the vehicle, the moving speed of the subject, the type of the subject, and the like. The image processing apparatus 3 has general hardware such as a storage unit 31, a control unit 32, and an input / output unit 33 connected by a bus as a hardware configuration.

The storage unit 31 stores various data and programs used in processing executed by the control unit 32 (not shown). The storage unit 31 may be realized, for example, by 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 acquired from a recording medium such as a CD (Compact Disc) or a DVD (Digital Versatile Disc). Furthermore, the storage unit 31 may be referred to as an auxiliary storage device.

As described above, the stereo camera 2 photographs the situation outside the vehicle via the windshield 1. Therefore, each image acquired by the stereo camera 2 is deformed according to the shape, refractive index, optical defect, and the like of the windshield 1. Therefore, in the present embodiment, the storage unit 31 stores correction data 311 for correcting the image deformed by the windshield 1.

Here, as shown in FIGS. 14A and 14B to be described later, when the shielding layer 11 is formed of a ceramic having a different thermal expansion coefficient from that of the glass plate, the present inventors have different surfaces depending on the surface on which the ceramic is printed on the laminated glass. It has been found that the lens power of the imaging windows (113A, 113B) varies. The lens power indicates the degree to which the light is bent. The larger the lens power value of each photographing window (113A, 113B), the more the direction of the light beam changes due to the passage of each photographing window (113A, 113B). That is, the present inventors have found that the amount of deformation generated in an image acquired through each photographing window (113A, 113B) differs depending on the surface of the laminated glass on which the ceramic is printed.

Therefore, in the correction data 311 stored in the storage unit 31, the amount of deformation corresponding to the surface on which the ceramic is printed on the laminated glass constituting the windshield 1 is determined. The control unit 32 can appropriately correct each image acquired by the stereo camera 2 by using such correction data 311. The data format of the correction data 311 may be appropriately selected according to the embodiment. For example, the correction data 311 may be data in a table format.

Such correction data 311 may be obtained, for example, by actually measuring the amount of distortion of a laminated glass (windshield) manufactured as a test product, and has the lens power shown in FIGS. 14A and 14B described later. It may be obtained by simulating the amount of distortion of the windshield. The method for obtaining the amount of distortion corresponding to the surface on which the ceramics are laminated can be appropriately selected according to the embodiment.

The control unit 32 includes one or more processors such as a microprocessor or a CPU (Central Processing Unit), and peripheral circuits (ROM (Read Only Memory), RAM (Random Access Memory), an interface circuit) used for processing of the processor. Etc.). ROM, RAM, and the like may be referred to as 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 analysis unit 321 by executing various data and programs stored in the storage unit 31.

The image analysis unit 321 analyzes the plurality of images acquired by the stereo camera 2 and calculates the position of the subject in the plurality of images, thereby acquiring information related to the situation outside the vehicle. 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 analysis unit 321 may acquire various information regarding the situation outside the vehicle based on a plurality of images with parallax based on a known method. Good. For example, the image analysis unit 321 can specify the type of subject by pattern matching or the like. Further, for example, the image analysis 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.

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

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

§2 Manufacturing Method Next, a manufacturing method of the windshield 1 according to the present embodiment will be described with reference to FIG. FIG. 6 schematically illustrates a manufacturing process of each glass plate (13, 14) of the windshield 1 according to the present embodiment. In addition, the manufacturing method of the windshield 1 demonstrated below is only 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.

First, the shaping process in the production line of each glass plate (13, 14) of the windshield 1 will be described. As illustrated in FIG. 6, in this production line, a heating furnace 901 and a molding device 902 are arranged in this order from upstream to downstream. And the roller conveyor 903 is arrange | positioned from the heating furnace 901 to the shaping | molding apparatus 902 and its downstream, Each glass plate (13, 14) used as a process target is conveyed by this roller conveyor 903. Each glass plate (13, 14) is formed in a flat plate shape before being carried into the heating furnace 901, and is carried into the heating furnace 901. Among these, the inner glass plate 14 is carried into the heating furnace 901 after the shielding layer 11 is further laminated.

The heating furnace 901 can have various configurations, but can be an electric heating furnace, for example. The heating furnace 901 includes a rectangular tube-shaped furnace main body whose upstream and downstream ends are open, and a roller conveyor 903 is disposed in the interior from upstream to downstream. Heaters (not shown) are respectively arranged on the upper surface, the lower surface, and the pair of side surfaces of the inner wall surface of the furnace body, and the temperature at which each glass plate (13, 14) passing through the heating furnace 901 can be formed, for example, Heat to near the softening point of the glass.

The forming apparatus 902 is configured to press a glass plate with an upper die 921 and a lower die 922 to form a predetermined shape. The upper die 921 has a curved surface that protrudes downward so as to cover the entire upper surface of each glass plate (13, 14), and is configured to be movable up and down. The lower mold 922 is formed in a frame shape corresponding to the peripheral edge of each glass plate (13, 14), and the upper surface thereof has a curved surface shape corresponding to the upper mold 921. With this configuration, each glass plate (13, 14) is press-formed between the upper die 921 and the lower die 922 and formed into a final curved shape. A roller conveyor 903 is disposed in the frame of the lower mold 922, and the roller conveyor 903 can move up and down so as to pass through the frame of the lower mold 922. And although illustration is abbreviate | omitted, the slow cooling apparatus (illustration omitted) is arrange | positioned in the downstream of the shaping | molding apparatus 902, and the shape | molded glass plate is cooled.

Here, the heating furnace 901 is heated at about 650 degrees. At that time, since the ceramic that is the material of the shielding layer 11 is a dark color such as black, compared with a region where the ceramic is not laminated, for example, the region of each imaging window (113A, 113B) and the non-shielding region 12. Increases heat absorption. And since the ceramic laminated | stacked on the shielding layer 11 has a thermal expansion coefficient different from the inner side glass plate 14 in the ceramic which is the material of the shielding layer 11, in the area | region in which the shielding layer 11 is formed, it is a compressive stress at the time of a shaping process. And tensile stress is generated. Furthermore, when the curvatures of the glass surfaces of the outer glass plate 13 and the inner glass plate 14 are different, the boundary between the inner glass plate 14 and the shielding layer 11 is likely to be distorted. That is, a distorted region in which the distortion described below is generated is formed at the peripheral portion of each photographing window (113A, 113B) and the boundary between the non-shielding region 12 and the shielding layer 11.

Therefore, in this embodiment, the shielding layer 11 is disposed so that the driver's visual field range 60 does not overlap the strain region. As a result, the vehicle equipped with the windshield 1 can provide the driver with a good field of view during driving.

In consideration of the width of the distorted area, each photographing window (113A, 113B) is formed so that the vertical and horizontal widths of each photographing window (113A, 113B) satisfy the above formula (1). Can do. Accordingly, it is possible to make the size of each shooting window (113A, 113B) relatively small while avoiding the influence of distortion on each shooting device (21A, 21B).

The roller conveyor 903 as described above is a known one, and a plurality of rollers 931 whose both ends are rotatably supported are arranged at predetermined intervals. There are various methods for driving each roller 931. For example, a sprocket can be attached to the end of each roller 931, and a chain can be wound around each sprocket to drive it. And the conveyance speed of each glass plate (13, 14) can also be adjusted by adjusting the rotational speed of each roller 931. FIG. The lower mold 922 of the forming apparatus 902 may be in contact with the entire surface of each glass plate (13, 14). In addition, if the shaping | molding apparatus 902 shape | molds a glass plate, the form of an upper mold | type and a lower mold | type will not be specifically limited.

Thus, when the outer glass plate 13 and the inner glass plate 14 are formed, the intermediate film 15 is sandwiched between the outer glass plate 13 and the inner glass plate 14, and this is put in a rubber bag and sucked under reduced pressure. While pre-adhering at about 70-110 ° C. The pre-adhesion method may be other methods. For example, the intermediate film 15 is sandwiched between the outer glass plate 13 and the inner glass plate 14 and heated at 45 to 65 ° C. in an oven. Subsequently, this laminated glass is pressed by a roll at 0.45 to 0.55 MPa. Next, the laminated glass is again heated at 80 to 105 ° C. in an oven and then pressed again with a roll at 0.45 to 0.55 MPa. Thus, preliminary adhesion is completed.

Next, this bonding is performed. The laminated glass that has been pre-bonded is subjected to main bonding by an autoclave at, for example, 8 to 15 atm and 100 to 150 ° C. For example, the main bonding can be performed under the conditions of 14 atm and 145 ° C. In this way, the laminated glass which comprises the windshield 1 which concerns on this embodiment is manufactured.

It should be noted that the angle at which such a laminated glass is attached to the automobile (hereinafter also referred to as “attachment angle”) can be appropriately set according to the embodiment. For example, the mounting angle of the laminated glass can be 45 degrees or less from the vertical.

§3 Features As described above, in the windshield 1 according to this embodiment, the shielding layer 11 that shields the field of view from the outside of the vehicle has the two imaging windows (113A, 113B). As a result, the stereo camera 2 installed in the vehicle can capture the situation outside the vehicle via the respective imaging windows (113A, 113B) and simultaneously acquire two images with parallax. In addition, by applying a known analysis process such as stereo vision to these two images, it is possible to acquire information such as the distance between the subject and the vehicle that is difficult to acquire with a single photographing device. Therefore, according to the present embodiment, it is possible to acquire information that is difficult to acquire with a single imaging device without using different types of measurement devices such as millimeter wave radar and laser radar. It is possible to provide the windshield 1 applicable to an in-vehicle system capable of acquiring sufficient information with a simple configuration.

In the present embodiment, the shielding layer 11 is formed by laminating ceramic on the inner surface of the inner glass plate 14 constituting the windshield 1 and heating the ceramic together with the inner glass plate 14. Here, as described later, the present inventors have found that when the shielding layer 11 is formed on the fourth surface with ceramic, the amount of distortion in each photographing window (113A, 113B) is the smallest. Therefore, according to the present embodiment, each imaging window (113A, 113B) with less distortion can be provided by forming a ceramic layer as the shielding layer 11 on the inner surface of the inner glass plate 14.

§4 Modifications Embodiments of the present invention have been described in detail above, but the above description is merely an illustration 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 constituent elements of the windshield 1, the stereo camera 2, and the image processing device 3, the constituent elements may be omitted, replaced, and added as appropriate according to the embodiment. For example, the following changes are possible. In the following description, the same components as those in the above embodiment are denoted by the same reference numerals, and the description thereof is omitted as appropriate.

<4.1>
For example, the glass plate of the windshield 1 according to the above embodiment is made of laminated glass in which an outer glass plate 13 and an inner glass plate 14 are bonded to each other via an intermediate film 15. However, the windshield 1 can have various configurations, and may be configured by a single glass plate, for example. Furthermore, in the said embodiment, the glass plate of the windshield 1 is formed in the substantially trapezoid shape. However, the shape of the glass plate of the windshield 1 may not be limited to such a shape, and may be appropriately selected according to the embodiment.

<4.2>
Further, for example, in the above embodiment, the shielding layer 11 is provided along the peripheral edge of the windshield 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 visual field range of the driver, the visibility of the driver is hindered by the shielding layer 11 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 60.

<4.3>
For example, in the said embodiment, the shielding layer 11 is laminated | stacked on the 4th surface of the laminated glass which comprises the windshield 1. FIG. However, the surface on which the shielding layer 11 is laminated need not be limited to the fourth surface of the laminated glass, and can be appropriately selected according to the embodiment. For example, the shielding layer 11 may be laminated on the second surface and / or the third surface of the laminated glass.

FIG. 7 is a cross-sectional view schematically illustrating the windshield 1 according to this modification. As illustrated in FIG. 7, dark ceramics such as black are screened on the inner surface (second surface) of the outer glass plate 13 and the inner surface (fourth surface) of the inner glass plate 14. The shielding layer 11 may be formed by laminating by printing or the like and heating the ceramic together with the glass plates (13, 14).

In addition, by forming the shielding layer 11 by laminating ceramics on the second surface and the fourth surface in this way, the shielding layer 11 having a two-layer structure can be formed. When the shielding layer 11 is viewed, the color of the shielding layer 11 can be increased. Therefore, according to the said structure, the appearance on the external appearance of the shielding layer 11 can be improved. Further, by laminating the ceramic on the fourth surface, it is possible to improve the adhesiveness when attaching the windshield 1 to the automobile. Further, the ceramic laminated on the fourth surface serves as a cushion between the inner glass plate 14 and the mounting portion of the automobile, so that the windshield 1 can be prevented from being easily broken at the mounting portion.

<4.4>
In the above-described embodiment, each photographing apparatus (21A, 21B) includes four lenses 221 to 224. However, the configuration of each imaging device (21A, 21B) can be changed as appropriate according to the embodiment. For example, as illustrated in FIGS. 8 and 9, each imaging device (25A, 25B) can be configured.

FIG. 8 illustrates the configuration of each photographing apparatus (25A, 25B) according to this modification. Each imaging device (25A, 25B) illustrated in FIG. 8 includes a lens system 26 having two plano-convex lenses (261, 262), an aperture stop 27 disposed on the subject side from the lens system 26, and the lens system 26. And an image sensor 28 that picks up an image by light that has passed through. In this modification, the aperture stop 27 is disposed on the subject side (left side in FIG. 8) of the lens system 26.

Therefore, in this case, since the position and size of the aperture stop 27 coincide with the entrance pupil, by providing the aperture stop 27 on each imaging window (113A, 113B), it is incident on each imaging window (113A, 113B). The pupil can appear. Therefore, in this case, the size of each imaging window (113A, 113B) can be reduced to the size of the entrance pupil.

Further, as illustrated in FIG. 9, the photographing apparatus may include a distortion correction plate 29. FIG. 9 shows an example in which the distortion correction plate 29 is provided in each of the imaging devices (25A, 25B) in the above modification. This distortion correction plate 29 can correct, for example, distortion (numerized by lens power) caused by a difference in curvature between the outer glass plate 13 and the inner glass plate 14 of the windshield 1 and can make the lens power zero. Such a distortion correction plate 29 can be configured to fit a windshield by appropriately processing a transparent plate member having a free-form surface.

<4.5>
In the above embodiment, the molding apparatus 902 that press-molds the outer glass plate 13 and the inner glass plate 14 of the windshield 1 has been described. However, the method for forming the glass plate of the windshield 1 is not limited to such an example, and may be formed by, for example, the self-weight bending method illustrated in FIG.

FIG. 10 illustrates a glass plate forming apparatus according to this modification. In this molding apparatus, first, a laminated glass (windshield 1) is prepared in which an intermediate film 15 is sandwiched between an outer glass plate 13 and an inner glass plate 14 on a flat plate. In this previous stage, the shielding layer 11 is laminated on the fourth surface and / or the second surface by screen printing or the like.

Then, this laminated glass is placed on a ring-shaped (frame-shaped) mold 800. This forming die 800 is disposed on a conveying table 801, and the conveying table 801 sequentially passes through the heating furnace 802 and the slow cooling furnace 803 in a state where the laminated glass is placed on the forming mold 800. At this time, since the mold 800 is ring-shaped, the laminated glass passes through the heating furnace 802 with only the peripheral edge supported. Then, when heated to near the softening point temperature in the heating furnace 802, the laminated glass is bent downward on the inner side from the peripheral edge by its own weight, and is formed into a curved surface shape. In addition, even if the windshield 1 is not a laminated glass but a single glass plate, it can be formed by the same method.

<4.6>
The intermediate film 15 can employ various modes. For example, a part of the intermediate film 15 may be dyed in a dark color such as black, and one region (stained region) of the intermediate film 15 may be configured as a part of the shielding layer 11. However, if this stained area overlaps each imaging window (113A, 113B), this stained area may hinder imaging by each imaging apparatus (21A, 21B). For this reason, the portion where the staining area and each imaging window (113A, 113B) overlap is replaced with a material having a high visible light transmittance so that the staining area does not overlap each imaging window (113A, 113B). May be.

<4.7>
Moreover, in the said embodiment, the stereo camera 2 has two imaging devices (21A, 21B). However, the number of imaging devices included in the stereo camera 2 is not limited to two, and may be three or more. In this case, the number of photographing windows provided in the shielding layer 11 may be set according to the number of photographing devices.

<4.8>
Further, the correction data 311 in the above embodiment, the size of each photographing window (113A, 113B), and the surface of the laminated glass on which the shielding layer 11 is provided can be applied not only to a stereo camera but also to a single camera. It is. Therefore, when a single camera is used without using a stereo camera, the number of shooting windows may be one.

<4.9>
Moreover, in the said embodiment, the shielding layer 11 is a single layer structure. However, the shielding layer 11 can have a multilayer structure. For example, the first ceramic layer is formed by laminating ceramics on the inner surface of the inner glass plate 14. Next, a silver layer is formed by laminating silver on the first ceramic layer. Furthermore, a second ceramic layer is formed by laminating a ceramic on the silver layer. Thereby, the shielding layer 11 having a three-layer structure can be formed. The shielding layer 11 having a three-layer structure can shield electromagnetic waves by a silver layer. In addition, the material of the composition shown in the following Table 2 can be utilized for this silver layer.

* 1, Main component: Bismuth borosilicate, Zinc borosilicate

<4.10>
Moreover, in the said embodiment, each imaging | photography window (113A, 113B) and the non-shielding area | region 12 are spaced apart. However, as illustrated in FIG. 11, each imaging window (113 </ b> A, 113 </ b> B) may be formed to be continuous with the non-shielding region 12.

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

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

(1) Configuration of glass plate: A laminated glass in which an outer glass plate and an inner glass plate are made of green glass having a thickness of 2 mm, and a single-layer interlayer film is disposed therebetween.
(2) Shielding layer: A shielding layer having a three-layer structure in which a silver layer was arranged in the composition shown in Table 2 between the first ceramic layer and the second ceramic layer having the composition shown in Table 1 above was formed. In addition, a trapezoidal photographing window was formed in the shielding layer.
(3) Production of glass plate: A first ceramic layer, a silver layer, and a second ceramic layer were screen-printed on the inner surface of the inner glass plate to form a shielding layer. The composition of the silver layer is shown in Table 2 below. Thereafter, it was baked to 650 ° C. in a heating furnace with a molding die as shown in FIG. 6 and formed into a curved shape, and gradually cooled after being conveyed from the heating furnace.

Subsequently, when the distortion of the glass plate near the boundary of the shielding layer was measured for the glass plate produced as described above, the result shown in FIG. 12 was obtained. In the graph of FIG. 12, the horizontal axis indicates the length in the surface direction of the glass plate, and the vertical axis indicates the lens power (millimeter diopter). (Diopter) is the reciprocal of the focal length due to the lens action, and its unit is (1 / m).

The method for measuring the lens power is as follows. First, light is projected onto a glass plate in a dark room, and a shadow is formed 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, when there is a concave lens action on the glass plate, it becomes dark. Here, there is a correlation between the lens power and the brightness of the shadow on the screen. 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 arranging the target glass plate and measuring the brightness on the screen over the entire surface of the glass.

As a result of such measurement, according to FIG. 12, the lens power increases rapidly and the distortion of the glass plate increases near the boundary from the shielding layer toward the non-shielding region. Recognize. And when it leaves | separates predetermined length from a boundary, it turns out that distortion reduces, and when it leaves | separates further, distortion lose | disappears.

Also, in order to examine the deformation of the image due to the distortion of the glass plate, a JIS-R3212 perspective distortion test was conducted on a glass plate having a trapezoidal shooting window in the shielding layer, and the scene was photographed. FIG. 13 shows a photograph thus obtained. As shown in FIG. 13, the perfect circle is deformed into an elliptical shape within 8 mm from the boundary between the shielding layer and the imaging window (distortion region). On the other hand, it can be seen that the vicinity of the center of the imaging 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, it is presumed that it is preferable to form the imaging window so that the vertical and horizontal widths satisfy the above-described formula 1 so that the imaging range of the imaging apparatus does not include the above-described distortion region with large distortion. Is done.

<Relationship between the surface on which the shielding layer is provided and the distortion of the shooting window>
Next, by the same method as described above, a glass plate in which a shielding layer is formed by laminating ceramic on the second surface, a glass plate in which a shielding layer is formed by laminating ceramic on the second surface and the fourth surface, and ceramic A glass plate in which a shielding layer was formed by laminating the film on the fourth surface was prepared, and the relationship between the surface on which the shielding layer was provided and the distortion of the photographing window was examined. In this embodiment, two photographing windows spaced apart from each other are formed on the shielding layer. Each photographing window was formed in a trapezoidal shape having an upper side width of 20 mm, a lower side width of 50 mm, and a height of 40 mm. Then, using the depth gauge (manufacturer name: Mitutoyo Corporation, model number: ID-C112RB), the horizontal curvature radii of each of the outer surface and the inner surface of the left and right photographing windows were measured. . In addition, the width of the depth gauge was 50 mm, and the radius of curvature of each surface of each imaging window was measured by applying a depth gauge to the portion where the width of the center of each imaging window (position of 30 mm height) was 50 mm. . Furthermore, the lens power in the horizontal direction of each photographing window was calculated by substituting the radius of curvature of each surface into the following equation (4).

However, the unit of lens power is (1 / m), the unit of R1 and R2 is m, and 1.52 is the refractive index of glass.

Note that the radius of curvature of the vehicle outer surface is substituted for R1 in Equation 4, and the radius of curvature of the vehicle inner surface is substituted for R2. As a result, the lens power of the left photographing window was obtained as shown in FIG. 14A. Moreover, the result shown by FIG. 14B was obtained about the lens power of the right imaging | photography window. The scale of the vertical axis is milli-diopter.

14A and 14B show that when the ceramic is laminated on the fourth surface, the lens power is almost zero on both the left and right sides. A lens power of 0 means that the curvature of the first surface and the fourth surface are the same, so the windshield does not have a concave lens function or a convex lens function, in other words, there is no convergence or divergence. To do. Therefore, from the result, it was found that by forming a shielding layer by laminating ceramics on the fourth surface, it is possible to form a photographing window that hardly generates lens power due to distortion. Moreover, it turned out that the deformation amount which arises in the image acquired through the imaging | photography window differs according to the surface which laminates | stacks a ceramic. For this reason, as described above, it has been found that the image acquired through the photographing window can be corrected appropriately by setting the correction value according to the surface on which the ceramic is printed.

On the other hand, when ceramic was laminated on the second surface, the lens power of each photographing window was −21.6 to −20 mdpt, indicating a tendency of a concave lens. When ceramics were laminated on the second surface and the fourth surface, an intermediate result was obtained between the case where the ceramics were laminated on the second surface and the case where the ceramics were laminated on the four surfaces.

From these results, the value of the lens power can be different depending on other factors such as the difference in curvature of the surface between the outer glass plate and the inner glass plate, but only on the fourth surface as shown in FIGS. 14A and 14B. It has been found that when ceramics are laminated, the lens power due to distortion hardly occurs in the photographing window. Further, it has been found that when ceramic is laminated only on the second surface, the lens power due to distortion occurs most in the photographing window. Further, in the case where ceramics are laminated on the second surface and the fourth surface, in the photographing window, a lens caused by distortion that is intermediate between the result of laminating the ceramic only on the second surface and the result of laminating the ceramic only on the fourth surface. It turns out that power is generated.

<Relationship between entrance pupil position and distortion>
Finally, in order to investigate the relationship between the position of the entrance pupil and the amount of distortion in the imaging window, an optical simulation as exemplified in FIG. 15 was performed. For this optical simulation, software OSLO Premium (Release 6.3) manufactured by Lambda Research, USA was used. And the windshield shall be comprised with one glass plate, and the thickness of the windshield was 4.8 mm. The glass plate was inclined 30 ° with respect to the horizontal direction, and the refractive index of the glass plate was 1.52. Furthermore, the curvature radius in the horizontal direction of the outer surface of the vehicle was 4800 mm. And the curvature radius of the vertical direction of the surface inside the vehicle was 1800 mm, and the curvature radius of the horizontal direction of the surface inside the vehicle was 4800 mm.

Here, the vertical radius of curvature of the outer surface of the vehicle was varied from 1600 mm to 2000 mm at intervals of 200 mm. Further, the distance (optical length in terms of air layer) between the entrance pupil of the photographing apparatus and the windshield (inner surface) was varied from -10 mm to 30 mm at intervals of 5 to 10 mm. Furthermore, a measurement point was set on a target placed at a position 1500 mm away from the windshield.

And the direction at the entrance pupil position of the light ray (chief ray) that emanates from the measurement point and passes through the center of the entrance pupil,
(A) When a windshield is placed (angle P)
(B) When no windshield is placed (angle Q)
The amount of distortion was calculated by the following equation (5).

This amount of distortion is a numerical value that does not depend on the focal length and F value of the photographing apparatus. The evaluated measurement points and directions were the Ay and Y directions, the Cy and Y directions, and the Ex and X directions shown in FIG. As a result, the results shown in FIGS. 16 and 17 were obtained. Note that the distance between the entrance pupil and the windshield being −10 mm means that the entrance pupil is separated from the windshield (inner surface) by an optical length of 10 mm toward the outside of the vehicle.

FIG. 16 shows the amount of distortion of the target imaged through the windshield when the distance between the entrance pupil of the camera and the windshield was varied from −10 mm to 30 mm at intervals of 10 mm. According to this result, when the curvature radius in the vertical direction outside the vehicle is set to 1800 mm, that is, when the shape of the same curvature radius is formed on the vehicle outer surface and the vehicle inner surface of the windshield, It was found that even when the distance between the entrance pupil and the windshield was varied, the variation in the amount of distortion was small.

In FIG. 16, the amount of distortion changes depending on the curvature of the windshield. By setting the distance D between the windshield and the entrance pupil to about 3 mm, the change in the amount of distortion due to the curvature of the windshield can be suppressed. I understood. That is, for example, when D is set to −10 mm, the amount of distortion of the target Cy varies from 1.1% to 2.7% when the curvature of the windshield is varied from 1600 mm to 2000 mm. On the other hand, when D was set to approximately 3 mm, even when the curvature of the windshield was varied from 1600 mm to 2000 mm, the amount of distortion of the target Cy did not vary at 1.9%. Further, for the target Ay, by setting D to approximately 6 mm, the variation in the distortion amount becomes almost zero. However, since the target Cy has a larger amount of absolute distortion and variation, it can be seen that the change in the amount of distortion due to the curvature of the windshield can be suppressed by setting the distance D between the windshield and the entrance pupil to approximately 3 mm. It was.

The shape of the windshield is curved for design and aerodynamic reasons. Since the glass plate has a constant thickness in terms of design, the lens power is almost zero, and distortion caused by the lens power hardly occurs. Further, if the shape of the curve is as designed, the amount of distortion caused by the curve can be calculated and dealt with. However, the distortion due to the lens power caused by the difference in curvature between the outer surface (first surface) and the inner surface (fourth surface) of the windshield causes a deviation from the design value. For this reason, when such distortion caused by the lens power occurs, it is difficult to correct the deformation of the image captured by the stereo camera only by the design value of the windshield, and it is difficult to correct the distortion caused by the lens power. Is required separately. On the other hand, as described above, since the generation of lens power can be suppressed by laminating ceramic only on the fourth surface, it is not necessary to deal with distortion caused by such lens power.

FIG. 17 shows the amount of distortion of the target imaged through the windshield when the curvature radius in the vertical direction of the outer surface of the vehicle is varied from 1600 mm to 2000 mm at intervals of 100 mm. According to this result, Cy had the largest variation in distortion. Specifically, when the distance between the entrance pupil of the camera and the windshield is set to 30 mm, the curvature of the point Cy is 3.3 when the vertical curvature radius of the outer surface of the vehicle is 1600 mm and 2000 mm. It varied by approximately 2.9% from% to 0.4%.

On the other hand, if the distance between the entrance pupil of the camera and the windshield is set to 10 mm, the variation in the distortion of the point Cy is 2.3% when the vertical curvature radius of the outer surface of the vehicle is 1600 mm and 2000 mm. From about 1.5% to about 0.8%. When the distance between the entrance pupil of the camera and the windshield is set to -10 mm, the variation in the distortion at the point Cy is 1.1 when the vertical curvature radius of the outer surface of the vehicle is 1600 mm and 2000 mm. % To 2.6% could be reduced to about 1.5%.

Therefore, by setting the distance between the entrance pupil of the camera and the windshield in a range of −10 mm to 10 mm, the image is taken through the windshield even if the vertical curvature radius of the outer surface of the vehicle is changed. It was found that the variation of the target distortion amount can be suppressed to some extent. In particular, by setting the distance between the entrance pupil of the camera and the windshield 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, for example, the surface provided with the shielding layer Thus, it has been found that even if variations occur due to lens power, fluctuations in the amount of distortion of the target imaged through the windshield can be substantially suppressed.

Here, the variation in the vertical radius of curvature of the vehicle outer surface indicates a manufacturing error of the windshield, and the variation in the distance between the windshield and the entrance pupil indicates an error when the camera is attached. In other words, when the curvature radius of the vehicle outer surface and the curvature radius of the vehicle inner surface are the same, the lens effect hardly occurs with the windshield, so the amount of distortion of the image taken through the windshield is Even if the distance between the windshield and the camera fluctuates, the value is almost constant. On the other hand, if the radius of curvature of the vehicle outer surface and the radius of curvature of the vehicle inner surface do not match due to manufacturing variations, the lens effect tends to occur in the windshield due to the mismatch, and the windshield The amount of distortion of the photographed image changes greatly when the distance between the windshield and the camera changes.

Since this discrepancy can vary due to manufacturing errors, the amount of distortion of the image taken through the windshield fluctuates due to this discrepancy. In this case, the correction value for correcting the image photographed through the windshield becomes a value specific to each windshield, and the correction value must be specified every time the windshield is manufactured.

On the other hand, according to the result of the above simulation, by setting the distance between the entrance pupil of the camera and the windshield in the range of −10 mm to 10 mm, the curvature radius of the vehicle outer surface and the curvature radius of the vehicle inner surface are set. It was found that even if the disagreement fluctuates, the fluctuation of the distortion amount of the image taken through the windshield 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 windshield in the range of 2 mm to 3 mm, fluctuations in the amount of distortion of the image taken through the windshield can be substantially suppressed. As a result, it is possible to prevent the amount of distortion of the image captured through each imaging window from fluctuating greatly due to manufacturing errors of the Indian shield, and to uniformly determine a correction value for correcting the captured image without considering individual differences. be able to.

1 ... Windshield,
DESCRIPTION OF SYMBOLS 11 ... Shielding layer, 111 ... Peripheral area | region, 112 ... Protrusion area | region, 113 (A * B) ... Shooting window,
12 ... non-shielding area,
13 ... outer glass plate, 14 ... inner glass plate, 15 ... intermediate film,
2 ... Stereo camera,
21 (A / B): photographing apparatus,
22 ... Lens system, 221 to 224 ... Plano-convex lens, 23 ... Aperture stop,
24. Image sensor,
25 (A / B) ... photographing device,
26: Lens system, 261, 262: Plano-convex lens, 27 ... Aperture stop,
28 ... Image sensor, 29 ... Distortion correction plate,
3 ... Image processing device,
31 ... Storage unit, 311 ... Correction data, 32 ... Control unit, 321 ... Image analysis unit,
33 ... Input / output unit,
60 ... field of view,
800 ... Mold, 801 ... Transfer, 802 ... Heating furnace, 803 ... Slow cooling furnace,
901 ... Heating furnace, 931 ... Roller,
902 ... Molding device, 921 ... Upper mold, 922 ... Lower mold,
903 ... Roller conveyor

Claims

A windshield for an automobile capable of arranging a stereo camera having a plurality of photographing devices spaced apart from each other so that a plurality of images with parallax can be obtained,
A glass plate,
A shielding layer that is provided on the glass plate and shields a field of view from outside the vehicle;
With
The shielding layer includes a plurality of photographing windows respectively corresponding to the plurality of photographing devices so that each of the plurality of photographing devices of the stereo camera arranged in a vehicle can photograph a situation outside the vehicle.
Windshield.
The shielding layer is configured by laminating a ceramic having a thermal expansion coefficient different from that of the glass plate on the inner surface of the glass plate, and the shielding layer depends on a difference in thermal expansion coefficient between the glass plate and the ceramic. Disposed so that the strain area where the glass plate is distorted at the peripheral edge of the vehicle and the visual field range where the driver driving the automobile confirms the traffic situation during driving do not overlap,
The windshield according to claim 1.
The glass plate is composed of laminated glass obtained by bonding an outer glass plate arranged on the vehicle outer side and an inner glass plate arranged on the vehicle inner side via an intermediate film,
The shielding layer is configured by laminating a ceramic having a thermal expansion coefficient different from that of the inner glass plate on the inner surface of the inner glass plate.
The windshield according to claim 1 or 2.
The glass plate is composed of laminated glass obtained by bonding an outer glass plate arranged on the vehicle outer side and an inner glass plate arranged on the vehicle inner side via an intermediate film,
The shielding layer is configured by laminating ceramics having different thermal expansion coefficients from the outer glass plate and the inner glass plate on the inner surface of the outer glass plate and the inner surface of the inner glass plate, respectively. To be
The windshield according to claim 1 or 2.
Each of the plurality of shooting windows is formed such that the vertical and horizontal widths of the plurality of shooting windows satisfy Expression (1).
The windshield according to claim 3 or 4.
H ≦ 2a + b + c (1)
In addition,
H is the vertical and horizontal width of the shooting window,
a is the width of the distorted region at the periphery of the imaging window,
b is the diameter of the entrance pupil,
c is the mounting error,
Show.
Each of the plurality of shooting windows is formed such that the vertical and horizontal widths of the plurality of shooting windows satisfy the formula (2).
The windshield according to claim 5.
b ≦ H (2)
An in-vehicle system for mounting on a vehicle including the windshield according to any one of claims 3 to 6,
A stereo camera having a plurality of imaging devices separated from each other so that a plurality of images with parallax can be acquired;
An image processing device that analyzes a plurality of images acquired by the stereo camera and calculates a position of a subject that is captured within a shooting range of the stereo camera;
With
The image processing device holds correction data for correcting an image deformed by the windshield, the correction data having a deformation amount determined in accordance with the ceramic laminated surface, and uses the correction data. To execute correction processing for each image,
In-vehicle system.
An in-vehicle system for mounting on a vehicle including the windshield according to any one of claims 3 to 6,
A stereo camera having a plurality of imaging devices separated from each other so that a plurality of images with parallax can be acquired;
An image processing device that analyzes a plurality of images acquired by the stereo camera and calculates a position of a subject that is captured within a shooting range of the stereo camera;
With
The optical system in each of the plurality of photographing devices of the stereo camera is configured such that the entrance pupil is present on the subject side with respect to the optical component.
In-vehicle system.
In the stereo camera, the distance between the entrance pupil of the optical system in each of the plurality of imaging devices and each of the plurality of imaging windows of the windshield in each of the plurality of imaging devices is within a range of within 10 mm in the front and rear direction. Arranged to be
The in-vehicle system according to claim 8.