JP2010268099A - Vehicle imaging device and vehicle periphery monitoring device - Google Patents

Abstract

The present invention suppresses the output of a false signal from an image sensor and appropriately monitors the external environment around the host vehicle.
An imaging apparatus for a vehicle includes a solid-state imaging element 72 having a light-receiving surface 72a that receives light collected by a lens, and a package base 71 that houses the solid-state imaging element 72 therein, and the light-receiving surface 72a. At least a plurality of different light transmissive material layers (light transmissive material layers 74a, 74b, 74c) filled in the package base 71, and the plurality of different light transmissive material layers are formed on the light receiving surface 72a. The light transmissive material layer closer to 2 has a larger refractive index.
[Selection] Figure 6

Description

  The present invention relates to a vehicle imaging device and a vehicle periphery monitoring device.

Conventionally, for example, near-infrared light is projected around the vehicle, and the reflected light resulting from reflection of the near-infrared light by an object outside the vehicle is received by a near-infrared light camera mounted on the vehicle. A vehicle periphery monitoring device that captures an image of an object outside the vehicle is known (see, for example, Patent Document 1).
Conventionally, for example, a solid-state imaging device that prevents the deterioration of the solid-state imaging device, such as oxidation or corrosion, by filling a light-transmitting material such as a light-transmissive silicone gel into a package in which the light receiving unit of the solid-state imaging device is accommodated. An apparatus is known (see, for example, Patent Document 2).

JP 2008-252327 A JP 58-57871 A

By the way, in the vehicle periphery monitoring device according to the above-described prior art, when a strong light is incident on the solid-state image sensor when an object outside the vehicle is imaged using the camera including the solid-state image sensor, the light is emitted from the light source. Since an electrical signal is output from pixels other than the pixels directly receiving light, there is a problem that blooming or halation occurs in which an originally dark place around the light source is displayed brightly.
For example, when taking an image of the outside world ahead of the direction of travel with a camera mounted on the host vehicle to assist visibility during night driving, the camera can capture the powerful light distributed from the headlamps of the oncoming vehicle. When the light enters the area, the area around the area where the headlight light source of the oncoming vehicle is brightly displayed by the false signal output from the solid-state image sensor. There is a problem that detection becomes difficult without being output.
In addition, there is a problem that a false signal is output when strong light is incident on the solid-state imaging device in this way. For example, there is a method of absorbing stray light by forming a light absorption layer inside the device. Are known. However, the main cause of the false signal output cannot be eliminated by simply reducing the already generated stray light. For this reason, it is desired to take appropriate measures to identify and eliminate the main cause of the false signal being output when strong light is incident on the solid-state imaging device.

  The present invention has been made in view of the above circumstances, and it is possible to suppress the output of a false signal from an image pickup device and the external environment around the host vehicle using the vehicle image pickup device. An object of the present invention is to provide a vehicle periphery monitoring device that can be appropriately monitored.

  In order to solve the above problems and achieve the object, the vehicle imaging device according to the first aspect of the present invention includes a lens (for example, the lens 21 in the embodiment) and light collected by the lens. An image sensor (for example, the solid-state image sensor 72 in the embodiment) having a light-receiving surface (for example, the light-receiving surface 72a in the embodiment) and a housing (for example, An imaging device for a vehicle mounted on a vehicle, wherein the at least a plurality of different light transmitting material layers filled in the housing so as to be stacked on the light receiving surface (For example, the light transmission material layers 74a, 74b, and 74c in the embodiment), and the plurality of different light transmission material layers have a larger refractive index as the light transmission material layer is closer to the light receiving surface.

For example, in the imaging device 90 according to an example of the prior art shown in FIGS. 7A and 7B, the surface of the solid-state imaging device 91 has irregularities with a pitch of several μm formed by a condensing microlens 92. A plurality of wiring layers 93 and a light shielding layer 94 are provided below the microlens 92. For this reason, the light reflected by the surface of the solid-state imaging device 91 includes a diffuse reflection component that is diffusely reflected, and this diffuse reflection component is reflected by a light transmission window 96 provided in the semiconductor package 95 and the like. As a result, the reflected light is incident on the peripheral pixels of the pixel to which the incident light is directly incident, and a false signal is output.
Therefore, in order to prevent the false signal from being output from the solid-state imaging device, it is only necessary to suppress the multiple reflection of the light that is collected by the lens 97 and incident on the solid-state imaging device 91.

  In the vehicle imaging device according to the first aspect of the present invention, when light is incident on the interface of materials having different refractive indexes, the reflectance increases as the refractive index difference increases. A plurality of different light-transmitting material layers are laminated on the light receiving surface so that the refractive index increases sequentially from the outside of the housing (that is, air) to the refractive index of the light receiving surface of the image sensor. Thus, the inside of the housing is filled.

  A vehicle periphery monitoring device according to a second aspect of the present invention is mounted on the vehicle imaging device according to the first aspect (for example, the vehicle imaging device 10 in the embodiment) and the vehicle exterior. Projecting means (for example, the projector 11 in the embodiment) that projects light in the visible region or near-infrared region, and the vehicle imaging device uses the light projected by the projecting unit. The reflected light is received and an object outside the vehicle is imaged.

  According to the vehicle imaging device of the first aspect of the present invention, the refractive index of a plurality of different light transmitting material layers filled in the housing sequentially increases to the refractive index of the light receiving surface of the imaging element, It is possible to suppress the light incident on the light receiving surface of the image sensor from the outside from being reflected due to a sharp change in refractive index at each interface.

  According to the vehicle periphery monitoring device according to the second aspect of the present invention, for example, even when strong light such as a headlight of an oncoming vehicle is incident on the vehicle image pickup device, the image pickup device of the vehicle image pickup device is false. It is possible to appropriately monitor the outside world around the host vehicle by suppressing the output of the signal.

It is a block diagram of the vehicle periphery monitoring apparatus which concerns on embodiment of this invention. It is sectional drawing which shows the imaging device for vehicles which concerns on the 1st Embodiment of this invention. It is a figure which shows an example of the change of the reflectance according to the incident angle of the s polarization wave and p polarization wave which concern on the 1st Embodiment of this invention. It is sectional drawing which shows the imaging device for vehicles which concerns on the 2nd Embodiment of this invention. It is sectional drawing which shows the imaging device for vehicles which concerns on the 2nd Embodiment of this invention. It is sectional drawing which shows the imaging device for vehicles which concerns on the 3rd Embodiment of this invention. It is sectional drawing which shows the imaging device and solid-state image sensor which concern on an example of a prior art.

Hereinafter, a vehicle imaging device and a vehicle periphery monitoring device according to a first embodiment of the present invention will be described with reference to the accompanying drawings.
The vehicle periphery monitoring device 1 according to the present embodiment is mounted on a vehicle, and performs predetermined monitoring based on an image obtained by imaging a predetermined monitoring target region in the outside of the vehicle with a vehicle imaging device 10 in a visible region or a near infrared region. It detects objects such as other vehicles and pedestrians existing in the area.
For example, as shown in FIG. 1, the vehicle periphery monitoring device 1 includes a vehicle imaging device 10, a projector 11, and a processing device 12.

The projector 11 projects light in the visible region or near-infrared region onto a predetermined monitoring target region in the outside of the vehicle in accordance with a control signal output from the processing device 12.
The processing device 12 controls the operation of the vehicular imaging device 10 and the projector 11, images the reflected light of the light projected by the projector 11 by the vehicular imaging device 10, and an image obtained by this imaging. Is subjected to predetermined image processing to detect an object existing in a predetermined monitoring area.

The vehicle imaging device 10 can capture an image in the visible region or the near-infrared region, and includes, for example, a lens 21 and a semiconductor package 22 as shown in FIG.
The semiconductor package 22 includes, for example, a package base 31 that forms a housing, a solid-state imaging device 32, a light transmission window 33, a polarizing film 34, a bonding wire 35, and a lead wire 36.

The package base 31 is formed in, for example, an open box shape, and contains a solid-state imaging device 32 disposed so as to face the lens 21.
The solid-state imaging device 32 is, for example, a CCD image sensor or a CMOS image sensor, and a light receiving surface 32 a that receives light collected by the lens 21 is formed at the center of the upper surface exposed toward the lens 21. .
The light receiving surface 32a includes, for example, a plurality of light receiving elements (not shown) arranged in a matrix, and a microlens (not shown) or the like is stacked on each light receiving element.
An electrode pad (not shown) provided on the periphery of the light receiving surface 32a is connected to a lead wire 36 by a bonding wire 35, and is connected to an external circuit (not shown) by the lead wire 36.

The light transmissive window 33 is made of, for example, a plate-like light transmissive glass, and is disposed so that the normal direction of the light transmissive window 33 is parallel to the optical axis O of the lens 21. The opening of the package base 31 accommodated is closed.
A polarizing film 34 is provided on the inner surface of the light transmission window 33. The polarizing film 34 transmits only a predetermined vibration component, for example, p-polarized light, out of the light collected by the lens 21 and transmitted through the light transmission window 33.
Thereby, the light incident on the lens 21 from the outside of the vehicle is condensed by the lens 21 and transmitted through the light transmission window 33, and then becomes p-polarized wave light by the polarizing film 34, and the light receiving surface 32 a of the solid-state imaging device 32. Is incident on.

In the package base 31, the solid-state imaging device 32 is arranged such that the normal line P of the light receiving surface 32 a is inclined by a predetermined angle θ with respect to the optical axis O of the lens 21.
The predetermined angle θ is, for example, the Brewster angle θb (= arctan (n2 / n1)) described by the refractive index n1 of the incident side material and the refractive index n2 of the transmission side material. When light is incident on the light receiving surface 32 a of the solid-state image sensor 32, the incident-side material is, for example, air inside the package base 31, and the transmission-side material is the light-receiving surface 32 a of the solid-state image sensor 32.

When light is incident on an interface of materials having different refractive indexes, the reflectance varies depending on the vibration component of the light. For example, as shown in FIG. In the case where light is incident on the transmission side material of glass which is 1.5, the reflectance of the s-polarized wave changes in an increasing trend as the incident angle with respect to the normal of the transmission side material increases from zero. On the other hand, the reflectance of the p-polarized wave decreased to zero at a predetermined Brewster angle (for example, about 56 degrees) as the incident angle with respect to the normal of the transmission side material increased from zero. Later, it turns into an increasing trend. That is, if the incident angle with respect to the normal of the transmission side material is the Brewster angle, the reflectance of the p-polarized wave is zero.
Since the normal line P of the light receiving surface 32a of the solid-state imaging device 32 is inclined by the Brewster angle θb with respect to the optical axis O of the lens 21, the light is condensed by the lens 21 and passes through the light transmission window 33 and the polarizing film 34. The reflectance of the p-polarized light that is transmitted and incident on the light receiving surface 32a is zero.

As described above, according to the vehicle imaging device 10 according to the first embodiment, light incident on the light receiving surface 32a of the solid-state image sensor 32 is transmitted to the inside of the package base 31 (for example, light transmission with the solid-state image sensor 32). Multiple reflections between the window 33 and the like, and false signals due to the reflected light can be prevented from being output.
And according to the vehicle periphery monitoring apparatus 1 which concerns on 1st Embodiment, even when it is a case where strong light, such as a headlamp of an oncoming vehicle, injects into the imaging device 10 for vehicles, of the imaging device 10 for vehicles. It can suppress that a false signal is output from the solid-state image sensor 32, and can appropriately monitor the external environment around the vehicle.

In the first embodiment described above, the polarizing film 34 is provided on the inner surface of the light transmission window 33. However, the present invention is not limited to this, and the polarizing film 34 is provided on the outer surface of the light transmission window 33. May be.
Instead of the polarizing film 34, a polarizing filter may be provided outside the package base 31, that is, between the lens 21 and the package base 31.

  In the first embodiment described above, the normal P of the light receiving surface 32a is inclined with respect to the optical axis O of the lens 21 by a predetermined angle θ due to the arrangement of the solid-state imaging device 32 inside the package base 31. However, the present invention is not limited to this. For example, in the package base 31, the light transmission window 33 and the light receiving surface 32a of the solid-state imaging device 32 are parallel (that is, the method of the light transmission window 33). The package base 31 may be disposed so as to be inclined by a predetermined angle θ with respect to the optical axis O of the lens 21.

Hereinafter, a vehicle imaging device and a vehicle periphery monitoring device according to a second embodiment of the present invention will be described with reference to the accompanying drawings.
The vehicle periphery monitoring device 1 according to the second embodiment differs from the vehicle periphery monitoring device 1 according to the first embodiment described above in that the vehicle imaging device 10 is the semiconductor of the first embodiment described above. Instead, the semiconductor package 42 according to the second embodiment is provided instead of the package 22.
For example, as shown in FIG. 4 or 5, the semiconductor package 42 according to the second embodiment includes, for example, a package base 51 that forms a housing, a solid-state imaging device 52, a light transmission window 53, a bonding wire 54, The lead wire 55 is provided.

The package base 51 is formed, for example, in an open box shape, and contains a solid-state imaging device 52 disposed so as to face the lens 21.
The solid-state image sensor 52 is, for example, a CCD image sensor or a CMOS image sensor, and a light receiving surface 52 a that receives light collected by the lens 21 is formed at the center of the upper surface exposed toward the lens 21. .
The light receiving surface 52a includes a plurality of light receiving elements (not shown) arranged in a matrix, for example, and a microlens (not shown) is stacked on each light receiving element.
In the package base 51, the solid-state imaging device 52 is arranged so that the normal line of the light receiving surface 52 a is parallel to the optical axis of the lens 21.
An electrode pad (not shown) provided in the periphery of the light receiving surface 52a is connected to a lead wire 55 by a bonding wire 54, and is connected to an external circuit (not shown) by the lead wire 55.

The light transmissive window 53 is made of, for example, a plate-like light transmissive glass, and is disposed such that the normal direction of the light transmissive window 53 is parallel to the optical axis of the lens 21, and the solid-state imaging device 52 is accommodated therein. The opening of the package base 51 is closed.
The inner surface of the light transmission window 53, that is, at least a part of the facing surface 53a facing the light receiving surface 52a of the solid-state imaging element 52 is a surface formed by a linear locus inclined with respect to the light receiving surface 52a. .

  The surface formed by a linear locus inclined with respect to the light receiving surface 52a is, for example, a cone formed such that the central portion of the inner surface of the light transmission window 53 protrudes toward the light receiving surface 52a of the solid-state imaging device 52. A cone surface (for example, a cone or a pyramid), a plane bent so as to protrude toward the light receiving surface 52a of the solid-state imaging device 52 as shown in FIG. 4, for example, or a solid as shown in FIG. For example, a flat surface inclined at a predetermined angle with respect to the light receiving surface 52 a of the image sensor 52.

  Of the light collected by the lens 21 and incident on the solid-state image sensor 52, the reflected light reflected by the diffused reflection or the like on the light-receiving surface 52a of the solid-state image sensor 52 is again reflected on the inner surface (opposing surface 53a) of the light transmission window 53. When reflected, if this facing surface 53a is inclined with respect to the light receiving surface 52a of the solid-state imaging device 52, for example, compared with the case where the facing surface 53a is parallel to the light receiving surface 52a, it is reflected by the facing surface 53a. The probability that the reflected light (that is, the reflected light reflected twice) is incident on the light receiving surface 52a of the solid-state imaging device 52 again becomes smaller.

And in the vehicle periphery monitoring apparatus 1 provided with the imaging device 10 for vehicles provided with the semiconductor package 42 concerning this 2nd Embodiment, it is at least one part of the inner surface (opposing surface 53a) of the light transmissive window 53, Comprising: A plane formed by a straight locus inclined with respect to 52a is inclined with respect to the left-right direction of the vehicle.
For example, when the vehicle periphery monitoring device 1 including the semiconductor package 42 illustrated in FIG. 5 is mounted on a vehicle that travels in a left-to-right manner, the opposing surface 53a The opposing surface 53a is inclined with respect to the light receiving surface 52a so that the distance between the light receiving surface 52a and the light receiving surface 52a changes in an increasing tendency.
As a result, even when strong light such as a headlight of an oncoming vehicle enters the vehicle imaging device 10 from the right side of the host vehicle, there may be a preceding vehicle or an obstacle, for example. Reflected light due to multiple reflections is incident on the area of the light receiving surface 52a corresponding to the front in the traveling direction of the high vehicle or the left side of the vehicle where there is a high possibility that a pedestrian or a parked vehicle is present. Can be suppressed.

As described above, according to the vehicle imaging device 10 according to the second embodiment, after the light is multiple-reflected between the solid-state imaging device 52 and the light transmission window 53 in the semiconductor package 42, the solid-state imaging device 52. Can be prevented from being incident on the light receiving surface 52a, and a false signal resulting from the reflected light of multiple reflection can be prevented from being output.
And according to the vehicle periphery monitoring apparatus 1 which concerns on 2nd Embodiment, even when it is a case where strong lights, such as a headlamp of an oncoming vehicle, inject into the imaging device 10 for vehicles, of the imaging device 10 for vehicles. It can suppress that a false signal is output from the solid-state image sensor 52, and can monitor the desired area | region of the external environment around a vehicle appropriately.

Hereinafter, a vehicle imaging device and a vehicle periphery monitoring device according to a third embodiment of the present invention will be described with reference to the accompanying drawings.
The vehicle periphery monitoring device 1 according to the third embodiment is different from the vehicle periphery monitoring device 1 according to the first embodiment described above in that the vehicle imaging device 10 is a semiconductor device according to the first embodiment described above. Instead, the semiconductor package 62 according to the third embodiment is provided instead of the package 22.
A semiconductor package 62 according to the third embodiment includes, for example, as shown in FIG. 6, a package base 71 that forms a housing, a solid-state image sensor 72, a light absorption layer 73, a sealing material 74, and antireflection. A film 75, a bonding wire 76, and a lead wire 77 are provided.

The package base 71 is formed in, for example, an open box shape, and contains a solid-state image sensor 72 disposed so as to face the lens 21.
The solid-state image sensor 72 is, for example, a CCD image sensor or a CMOS image sensor, and a light receiving surface 72 a that receives light collected by the lens 21 is formed at the center of the upper surface exposed toward the lens 21. .
The light receiving surface 72a includes, for example, a plurality of light receiving elements (not shown) arranged in a matrix, and a microlens (not shown) or the like is laminated on each light receiving element.
In the package base 71, the solid-state image sensor 72 is arranged so that the normal line of the light receiving surface 72 a is parallel to the optical axis of the lens 21.
An electrode pad (not shown) provided around the light receiving surface 72a is connected to a lead wire 77 by a bonding wire 76, and is connected to an external circuit (not shown) by the lead wire 77.

Then, for example, a plate-shaped light absorption layer 73 having an opening larger than the light receiving surface 72 a is provided in the opening of the package base 71 in which the solid-state imaging element 72 is accommodated. An antireflection film 75 covering the opening is provided.
A plurality of different light transmissive material layers (for example, three light transmissive material layers 74a, 74b, and 74c) stacked on the light receiving surface 72a are provided inside the package base 71 in which the solid-state imaging device 72 is accommodated. A light-transmitting sealing material 74 is filled.
The plurality of different light transmitting material layers constituting the sealing material 74 have a larger refractive index as the light transmitting material layer is closer to the light receiving surface 72a. The refractive index of the plurality of light transmitting material layers is, for example, a semiconductor. The refractive index of the air outside the package 62 is set so as to increase sequentially from the refractive index of the light receiving surface 72a of the solid-state imaging device 72.

The sealing material 74 has a refractive index between the refractive index of the air outside the semiconductor package 62 and the refractive index of the light receiving surface 72a of the solid-state imaging device 72, and is made of, for example, epoxy resin, silicon resin, glass, or the like. .
Further, an antireflection layer (not shown) for suppressing light reflection is provided on the inner wall surface of the package base 71.

As described above, according to the vehicular imaging apparatus 10 according to the third embodiment, in the semiconductor package 62, refraction is sequentially performed from the air outside the semiconductor package 62 to the light receiving surface 72a of the solid-state imaging device 72. By setting the rate to change in an increasing trend, it is possible to suppress an increase in the reflection of light due to a sharp change in refractive index, and a false signal resulting from the reflected light of multiple reflections is output. Can be suppressed.
And according to the vehicle periphery monitoring apparatus 1 which concerns on 3rd Embodiment, even when it is a case where strong lights, such as a headlamp of an oncoming vehicle, inject into the imaging device 10 for vehicles, of the imaging device 10 for vehicles It can suppress that a false signal is output from the solid-state image sensor 72, and can appropriately monitor the external environment around the vehicle.

In the first to third embodiments described above, the bonding wires 35, 54, and 76 formed by wire bonding are present on the surface of the solid-state imaging device 32, 52, and 72. However, the present invention is not limited to this. For example, the semiconductor packages 22, 42, and 62 may be mounted by flip chip bonding.
Thereby, it is possible to prevent the multiple reflection of light from being promoted by the bonding wires 35, 54 and 76 existing on the surfaces of the solid-state imaging devices 32, 52 and 72. In particular, in the third embodiment described above, the thickness of the semiconductor package 62 and the thickness of the sealing material 74 filled in the package base 71 can be reduced. Distortion of an image obtained by imaging can be suppressed.

DESCRIPTION OF SYMBOLS 1 Vehicle periphery monitoring apparatus 10 Vehicle imaging device 11 Floodlight (light projection means)
21 Lens 71 Package Base (Housing)
72 Solid-state imaging device (imaging device)
72a Light receiving surface 74a, 74b, 74c Light transmitting material layer

Claims (2)

An imaging device for a vehicle mounted on a vehicle, comprising: a lens; an imaging device having a light receiving surface that receives light collected by the lens; and a housing that houses the imaging device;
Comprising at least a plurality of different light transmitting material layers filled in the housing so as to be laminated on the light receiving surface;
The plurality of different light transmissive material layers have a higher refractive index as the light transmissive material layer is closer to the light receiving surface. The vehicle imaging device according to claim 1;
A light projecting means mounted on the vehicle and projecting light in a visible region or near infrared region toward the outside of the vehicle;
The vehicle image pickup apparatus receives a reflected light of the light projected by the light projecting unit and images a target object outside the vehicle.

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