WO2019039502A1

WO2019039502A1 - Reflective optical element and stereo camera device

Info

Publication number: WO2019039502A1
Application number: PCT/JP2018/030949
Authority: WO
Inventors: 嘉則杉浦; 勝元細川; 裕之久保
Original assignee: キヤノン株式会社
Priority date: 2017-08-24
Filing date: 2018-08-22
Publication date: 2019-02-28
Also published as: CN114994815A

Abstract

Provided is a reflective optical element having a light weight and excellent vibration damping characteristics. This reflective optical element has a resin layer on a metal substrate, said resin layer having an optical surface, and the optical surface is provided with a reflecting film. The reflective optical element is characterized in that the metal substrate contains an alloy having Mg as a main component.

Description

Reflective optical element and stereo camera device

The present invention relates to, for example, a reflective optical element excellent in lightness and vibration controllability, which is used as a vehicle.

The reflective optical system is easy to make the entire optical system smaller as compared with the refractive optical system, and has advantages such as no shift in imaging due to wavelength.

Also, in recent years, as imaging devices have become smaller and more sophisticated, they have been actively mounted not only on conventional cameras, videos and smartphones, but also on mobile objects such as drone and automobiles, and visual recognition of the surrounding environment has been made In addition, it is used for more extensive and high-precision applications such as ranging.

Taking autos as an example, in addition to infrared laser scanners and millimeter wave radars, research has also been conducted on mounting cameras in addition to infrared laser scanners and millimeter-wave radars in order to realize future autonomous driving. Be When using a camera for such an application, the lightness in weight and the difficulty of performance degradation due to vibration can be very important elements in the specification.

In a reflection optical system, a mirror is mainly used as an optical element, but Patent Document 1 discloses a lightweight, relatively inexpensive mirror and a method of manufacturing the same. In the mirror, an aluminum die-cast product is used as a substrate, a soft and hard radiation-cured resin layer is provided thereon, and a metal reflection film such as aluminum is further formed thereon.

JP-A-5-107407

However, although such a mirror having a configuration using aluminum as a substrate is lightweight, it can be used for moving objects such as cars, aircrafts, drones, ships, and cameras such as cameras having a physical drive unit in the vicinity, copying machines, etc. Deterioration of optical performance due to vibration may be a problem in the application of the device. This is a problem caused by the fact that aluminum and its alloys are generally low damping materials.

The present invention has been made in view of the above problems, and provides a reflective optical element that is lightweight and has excellent vibration controllability.

According to the present invention, there is provided a reflection optical element comprising a resin layer having an optical surface on a metal substrate, and a mirror provided with a reflection film on the optical surface, wherein the metal substrate has a first connection. A first opening for taking light into an imaging optical system, a plurality of mirrors of a first imaging optical system for reflecting light taken in from the first opening, and a light for taking a second imaging optical system A second opening and a plurality of mirrors of a second imaging optical system for reflecting light taken in from the second opening are provided, and the metal substrate contains an alloy containing Mg as a main component A reflective optical element is provided.

According to the present invention, it is possible to provide a reflective optical element that is lightweight and has excellent damping properties.

FIG. 1 is a perspective view showing an embodiment of a reflective optical element according to the present invention. It is a sectional view showing one embodiment of an optical device concerning the present invention. It is a sectional view showing one embodiment of an optical device concerning the present invention. FIG. 1 is a schematic cross-sectional view of a stereo camera body according to an embodiment of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS Typical sectional drawing which shows the structure of the reflective surface of embodiment of this invention. FIG. 1 is an external perspective view of a stereo camera body according to an embodiment of the present invention. FIG. 1 is an external perspective view of a stereo camera body according to an embodiment of the present invention. The figure which shows the structure of the metal substrate of the stereo camera main body of embodiment of this invention. The typical fragmentary sectional view of the example which provided a plurality of heat conduction paths. Sectional drawing which showed typically the housing | casing of the double structure of embodiment of this invention. The figure which shows the concrete structure of the housing | casing of the double structure of embodiment of this invention. FIG. 1 is an external perspective view of a stereo camera device according to an embodiment of the present invention. FIG. 1 is a front view of a stereo camera device according to an embodiment of the present invention. A closed automobile equipped with a stereo camera device according to an embodiment of the present invention. An open automobile equipped with a stereo camera device according to an embodiment of the present invention. The flowchart which shows the manufacture procedure of embodiment of this invention. The schematic diagram which shows the manufacturing method of a metal substrate. Typical sectional drawing which shows the manufacturing method of the resin part of embodiment of this invention. Typical sectional drawing which shows the manufacturing method of the resin part of embodiment of this invention. FIG. 5 is a schematic view showing a method of manufacturing a reflective film according to an embodiment of the present invention. The schematic diagram which shows the optical axis adjustment by the support stand of embodiment of this invention.

According to the present invention, the problem of the present invention can be solved by the above configuration, and specifically, the following embodiments can be employed.

The reflective optical element according to the present invention is a reflective optical element including a resin layer having an optical surface on a metal substrate, and a mirror provided with a reflective film on the optical surface, wherein the metal substrate includes: A first opening for taking light into a first imaging optical system, a plurality of mirrors of the first imaging optical system for reflecting light taken in from the first opening, and a second imaging optical system A second opening for taking in light and a plurality of mirrors of a second imaging optical system for reflecting the light taken in from the second opening are provided, and the metal substrate is mainly composed of Mg. It is characterized in that it comprises an alloy, more preferably a Mg-Li alloy, which will be described in detail below based on its embodiment.

(First embodiment)
A schematic perspective view of an example of a reflective optical element according to a first embodiment of the present invention is shown in FIG. In FIG. 1, 1 is a metal substrate, 2 is a resin layer formed on the metal substrate 1, and the resin layer 2 has an optical surface. The present embodiment is configured as a reflective optical element by providing the reflective film 3 on the optical surface. Here, the metal substrate 1 is characterized in that it is an alloy mainly composed of Mg, more preferably a Mg—Li alloy.

[Metal substrate]
The metal substrate 1 in the present embodiment is formed of an alloy containing Mg as a main component, more preferably a Mg—Li alloy. Although the Mg-Li alloy is not particularly limited, it is a magnesium-lithium alloy in which at least lithium is added to magnesium, preferably 5% by mass or more and 20% by mass or less of lithium, and 0.5% by mass of aluminum As mentioned above, 15 mass% or less may be contained, and also 5 mass% or less of calcium may be contained, and the remainder consists of magnesium. That is, the metal substrate 1 contains Mg as a main component, and specifically contains 60% by mass or more of Mg. The amount of unavoidable impurities is preferably smaller.

More specifically, LA Dex (trade name; Li, Al, Mg alloy containing Ca) manufactured by Santoku Co., Ltd., ALZ manufactured by Anritsu Materials Technology Co., Ltd. (trade name: Mg alloy containing Al, Li, Zn) And alloys such as

There is no restriction | limiting in particular in the shaping | molding method of a Mg-Li alloy board | substrate, It can shape | mold by well-known various methods, such as forging and injection molding. In general, a substrate that has been primarily processed by forging or injection molding may be subjected to secondary processing after annealing to satisfy a desired dimensional accuracy as a substrate, and then may be subjected to an anticorrosion treatment.

Conventionally, it has been well known that pure Mg materials have high damping properties, but their specific strength is low, and they are flammable and are therefore less practical. On the other hand, alloyed Mg materials such as AZ91 (9% Al-1% Zn-Mg) and AM60 (6% Al-0.4% Zn-Mg) are suitably improved in specific strength etc. Although it is a high material, the high damping property which pure Mg material had by alloying is impaired. Mg alloys are classified as dislocation type in the damping alloy category, but Mg-Li alloys may belong to other different categories such as composite types, and the inventors of the present invention have their unique characteristics. I found it. This characteristic can effectively damp the vibration when used in a moving object or in a member close to a vibration source, and can effectively reduce the deterioration of functions originally possessed by the imaging device etc. .

[Resin layer]
The material of the resin layer in the present invention is not particularly limited, and various known resins can be used.

When forming a resin layer and its optical surface by heat press molding, a desired resin pellet, a film, a melt, etc., a mold having the desired optical surface, an alloy mainly comprising Mg as a substrate, More preferably, it is placed between Mg—Li alloys. Then, it can be heated to a temperature equal to or higher than the melting temperature and pressure-formed by a known method.

The resin used for the resin layer in the present invention is not particularly limited as long as it satisfies the desired properties, but acrylic resins, ester resins, ether resins, amide resins, imide resins, olefin resins, fluorine resins, etc. are known. Resin can be used. When it is desired to particularly suppress deformation due to water absorption of the resin layer, it is preferable to use an olefin-based resin, more preferably a cyclic olefin-based resin.

When forming a resin layer by radiation curing molding, the desired radiation curing resin is between a mold having a desired optical surface and an alloy mainly composed of Mg as a substrate, more preferably a Mg-Li alloy. It can be installed, filled and cured by radiation.

In this case, the resin to be used is not particularly limited as long as it satisfies the desired characteristics, but known resins such as acrylic resins, epoxy resins, cyanate resins and fluorine resins can be used. In consideration of the stability of the optical surface of the resin layer, preferably an acrylic type or an epoxy type can be used. When it is desired to control the surface accuracy of the optical surface more suitably, a radiation curable resin having a small cure shrinkage can be used.

The thickness of the resin layer is not particularly limited, but is preferably 20 μm or more and 2000 μm or less, more preferably 50 μm or more and 1000 μm or less, in particular when distortion of the optical surface due to thermal expansion is particularly concerned. If the thickness of the resin layer is too thin, it may be affected by the surface roughness of the Mg-based alloy serving as the substrate, more preferably Mg-Li alloy, and the surface roughness of the optical surface may not be the desired roughness. . If the thickness of the resin layer is too thick, the effect of reducing distortion of the optical surface due to thermal expansion of the resin due to the support of the substrate is not sufficiently exerted, and the desired optical surface may not be maintained in the temperature range in the use environment. Come out.

In order to improve the adhesion between the resin layer and the substrate, known methods such as surface treatment of the substrate and primer treatment can be used before forming the resin layer. When it is desired to reduce the residual stress due to the formation of the resin layer in the shape stability of the optical surface, annealing may be performed after the formation of the resin layer.

[Reflective film]
As a reflective film provided on the optical surface of the resin layer in the present embodiment, a known reflective film made of aluminum, silver, chromium or the like can be used. From the viewpoint of reflectance, a reflective film of preferably aluminum or silver, more preferably silver can be used. Furthermore, a protective film, a reflection increasing film, etc. may be provided on the surface of the reflecting film, and various known film configurations can be used within the range showing desired characteristics.

Second Embodiment
A schematic cross section of an example of an optical device having a connecting portion, which is a second embodiment of the present invention, is shown in FIG. FIG. 2 shows an example of an optical apparatus holding an optical unit having a plurality of mirrors by a connecting unit. Specifically, it shows an image projection apparatus having a projection optical system which projects an image displayed on the image display panel 23 on a screen in an enlarged manner.

In FIG. 2, M1 to M6 are mirrors which are functional units. 22 is a protective glass. The mirrors M1 to M6 are positioned by the base portion 21. In the present embodiment, an example is shown in which the base portion 21 is formed by the metal portion 211 made of metal and the resin portion 212 made of resin, but the invention is not limited thereto, and it is possible to hold the mirrors M1 to M6. It may be in any form. The metal portion 211 can be an alloy in which all or at least a portion thereof contains Mg as a main component, more preferably a Mg—Li alloy. Reference numeral 24 denotes a connecting part for attaching the optical part having the mirrors M1 to M6 as the functional part and the base part 21 to another member. The connecting portion 24 may be a single member integrally formed with the base portion 21 or may be a separate member from the base portion 21. That is, the optical device according to the present embodiment may be formed of the optical portion and the connecting portion.

In this embodiment, the connecting part 24 for attaching the optical part having the mirrors M1 to M6 and the base part 21 as the functional part to another member is made of an alloy mainly composed of Mg, more preferably a Mg-Li alloy. It is characterized by being formed. Alternatively, the portion 25 of the connecting portion 24 may be formed of an alloy mainly composed of Mg, more preferably a Mg—Li alloy, and the other portion may be formed of another metal. The connecting portion formed of an alloy mainly composed of Mg, more preferably a Mg—Li alloy, is excellent in damping property and lightweight, and is suitable as a damping member.

The mirrors M1 to M6, which are functional units, may be the reflective optical elements described in the first embodiment. That is, it is a mirror in which a reflective film is formed on the surface of a metal substrate (hereinafter also referred to as a substrate portion), and the substrate portion is formed of an alloy containing Mg as a main component, more preferably Mg-Li alloy It is also good.

Further, instead of the mirror in which the reflective film is formed on the surface of the substrate portion, it may be a mirror in which the reflective film is formed directly on the base portion 21. In this case, the base portion 21 also serves as a substrate portion.

A known reflective film made of aluminum, silver, chromium or the like can be used as the reflective film. From the viewpoint of reflectance, a reflective film of preferably aluminum or silver, more preferably silver can be used.

A protective film, a reflection increasing film, etc. may be further provided on the surface of the above-mentioned reflective film, and various known film configurations can be used within the range showing desired characteristics.

In the present embodiment, as in the first embodiment, the Mg—Li alloy is not particularly limited, but is a magnesium-lithium alloy in which at least lithium is added to magnesium, preferably 5% by mass of lithium As mentioned above, 20 mass% or less, 0.5 mass% or more and 15 mass% or less of aluminum may be contained, calcium may be further contained 5 mass% or less, and the balance is made of magnesium. That is, the Mg—Li alloy contains Mg as a main component and contains 60% by mass or more of Mg. The amount of unavoidable impurities is preferably smaller.

More specifically, LAX (trade name) manufactured by Santoku Co., Ltd. having a composition described above, ALZ manufactured by Anritsu Materials Technology Co., Ltd., and the like can be mentioned.

Third Embodiment
A schematic cross section of a reflective optical element, which is a third embodiment of the present invention, is shown in FIG. FIG. 3 shows a metal substrate, a first opening for taking light into a first imaging optical system, and a plurality of mirrors of the first imaging optical system for reflecting light taken from the first opening. Stereo camera apparatus provided with a second opening for taking light into a second imaging optical system, and a plurality of mirrors of the second imaging optical system for reflecting light taken from the second opening An example is shown. Specifically, it shows a schematic cross section of a device having a shape similar to the imaging device described in, for example, JP-A-2017-044722.

FIG. 3 shows how light is taken in from the two openings SP1 and SP2, respectively, reflected sequentially by the reflecting surface mirrors R2 to R8, and imaged on the imaging elements IMG1 and IMG2. R2 to R8 are mirrors which are functional units. The mirrors R2 to R8 are positioned by the base portion 31, respectively. In the present embodiment, an example is shown in which the base portion 31 is formed by the metal portion 311 made of metal and the resin portion 312 made of resin, but the invention is not limited thereto, and it is possible to hold the mirrors R2 to R8. It may be in any form. The metal portion 311 can be an alloy in which all or at least a portion thereof contains Mg as a main component, more preferably a Mg—Li alloy. Reference numeral 34 denotes a connecting portion for attaching the optical portion having the function units, ie, the mirrors R2 to R8 and the base portion 31, to another member. The connecting portion 34 may be a single member integrally formed with the base portion 31 or may be a separate member from the base portion 31. That is, the optical device according to the present embodiment may be formed of the optical unit and the connection unit.

In the present embodiment, the connecting part 34 for attaching the optical part having the mirrors R2 to R8 as the functional part and the base part 31 to another member is made of an alloy containing Mg as a main component, more preferably Mg-Li alloy. It is characterized by being formed. Alternatively, a part 35 of the connection part 34 may be formed of an alloy mainly composed of Mg, more preferably a Mg—Li alloy, and the other part may be formed of another metal. The connecting portion formed of an alloy mainly composed of Mg, more preferably a Mg—Li alloy, is excellent in damping property and lightweight, and is suitable as a damping member.

The mirrors R2 to R8 which are functional units may be the reflection optical elements described in the first embodiment. That is, it is a mirror in which a reflective film is formed on the surface of a metal substrate (hereinafter also referred to as a substrate portion), and the substrate portion is formed of an alloy containing Mg as a main component, more preferably Mg-Li alloy It is also good.

Further, the mirror may be a mirror in which the reflection film is formed directly on the base 31 instead of the mirror in which the reflection film is formed on the surface of the substrate. In this case, the base portion 31 also serves as the substrate portion.

A protective film, a reflection increasing film, etc. may be further provided on the surface of the above-mentioned reflective film, and various known film configurations can be used within the range showing desired characteristics. Alternatively, the mirror which is the functional part is not only made of the mirror in which the reflective film is formed on the surface of the substrate as described above, but may also include the mirror in which the reflective film is directly formed on the base 31. Good. In this case, the base portion 31 also serves as the substrate portion.

EXAMPLES The present invention will be more specifically described below with reference to examples and comparative examples, but the present invention is not limited to these examples.

(Measurement of vibration loss factor)
In each of the following examples and comparative examples, the vibration loss coefficient is used as an index to indicate the damping property of various metal substrates such as Mg-Li alloy substrate, Mg alloy substrate and Al alloy substrate. It measured by. The vibration loss coefficient is a scale showing damping performance, and the higher the value, the higher the damping performance.

Specifically, various metal substrates are cut out to a predetermined size and both ends of the substrate long sides are held, and then the metal substrates are subjected to vibration loading and unloading by a vibrating electromagnetic coil, and the substrate center after unloading. The amount of amplitude variation was measured by a laser displacement meter. The excitation frequency at this time is the resonance frequency of various metal substrates, the internode distance is 40 mm, the coil inductance is 101 K (100 μH), the voltage is a sine wave 1 Vp-p, and eddy currents generated on the sample surface are used. It vibrated.
The vibration loss coefficient was determined from Equation 1 from the time-dependent measurement value of the obtained amplitude variation.

x: time, y: amplitude variation amount, f: frequency, η: vibration loss coefficient

Example 1
Vibration loss coefficient by the above method using Mg-Li alloy substrate (LAX1491 (trade name); 14% Li-9% Al-1% Ca-Mg made by Santoku Co., Ltd.) of 90 mm × 10 mm × 0.5 mm size Was determined (excitation frequency: 1.04 kHz). The results are shown in Table 1. The specific gravity of LAX1491 (trade name) is also shown in Table 1.

Example 2
The vibration loss coefficient was determined by the above method using a 98 mm × 10 mm × 2 mm Mg alloy substrate (AZ91 (9% Al-1% Zn—Mg)) (excitation frequency: 2.82 kHz). The results are shown in Table 1. The specific gravity of AZ91 is also shown in Table 1.

Comparative Example 1
The vibration loss coefficient was determined by the above method using an Al-Si-Mg-based aluminum alloy substrate (AC4C (7.5% Si-0.45% Mg-Al)) of 98 mm × 10 mm × 2 mm size (excitation vibration) Frequency: 3.30 kHz). The results are shown in Table 1. The specific gravity of AC4C is also shown in Table 1.

From the above results, when at least a part of the predetermined member is made of an alloy mainly composed of Mg, more preferably a Mg-Li alloy, it is possible to use a reflection optical element that is lightweight and has high damping performance, and a damping member I found that I could get it.

Fourth Embodiment
Hereinafter, a stereo camera device according to a fourth embodiment of the present invention and a method of manufacturing the same will be described with reference to the drawings. According to the fourth embodiment, it is possible to provide a compact stereo camera device at low cost, in which the reduction in the accuracy of stereo measurement is suppressed even when heating or cooling is received locally.

(Stereo camera body)
FIG. 4A is a schematic cross-sectional view for illustrating the basic configuration of a stereo camera body according to the fourth embodiment.

The stereo camera body 101 includes a stereo imaging optical system STU, and the stereo imaging optical system STU is configured of a first imaging optical system LO1 on the right side in the drawing and a second imaging optical system LO2 on the left side in the drawing. .

The first imaging optical system LO1 has an opening SP11 as a first opening for receiving external light, a reflective surface R11, a reflective surface R12, a reflective surface R13, a reflective surface R14, and a reflective surface R15. The second imaging optical system LO2 has an aperture SP12 as a second aperture for taking in external light, a reflective surface R21, a reflective surface R22, a reflective surface R23, a reflective surface R24, and a reflective surface R25. Each reflective surface is formed as a free-form surface mirror. The opening SP11 and the opening SP12 may be used as a stop of the first imaging optical system LO1 and the second imaging optical system LO2.

In FIG. 4A, reference axes (central chief rays) of the first imaging optical system LO1 and the second imaging optical system LO2 are indicated by alternate long and short dashed lines, but two reference axes are bent by a plurality of tilted reflecting surfaces. An off-axial optical system (off-axial optical system) is configured. Preferably, the first imaging optical system LO1 and the second imaging optical system LO2 are configured to be symmetrical to each other. If the angle of view of the left and right optical systems is different, the range in which the distance can be measured by stereo measurement is determined by the image forming optical system having the narrower angle of view. In addition, if there is a difference between the f-numbers and focal lengths of the two optical systems, the accuracy of distance measurement may be reduced.

The stereo camera body 101 includes a first metal substrate (first metal frame) 102 and a second metal substrate (second metal frame) 103, and includes a first imaging optical system LO1 and a second imaging optical system. LO2 is mounted on the metal substrate as follows.

The first metal substrate 102 has an opening SP11 as a stop surface for taking in external light into the first imaging optical system LO1, and a reflecting surface R12 that constitutes a part of the first imaging optical system LO1. A reflective surface R14 is provided. Further, the first metal substrate 102 is provided with an opening SP12 as a stop surface for taking in external light into the second imaging optical system LO2, and a reflecting surface which constitutes a part of the second imaging optical system LO2. R22 and a reflective surface R24 are also provided. Furthermore, on the first metal substrate 102, the image sensor IMG11 is fixed at a position corresponding to the imaging surface of the first imaging optical system LO1, and the image sensor IMG12 is fixed at a position corresponding to the imaging surface of the second imaging optical system LO2. It is fixed.

As the image sensor, for example, an imaging element having sensitivity to visible light (wavelength: 380 nm to 700 nm) such as a CMOS image sensor or a CCD image sensor is used. However, in addition to visible light, it is more preferable if light in a wavelength band different from visible light (for example, a near infrared region around 1000 nm) can also be received and converted into an electrical signal. As in the present embodiment, in the case of an imaging optical system in which an optical surface having refractive power (optical power) is constituted only by a reflection surface, no chromatic aberration exists, and therefore, an imaging optical system constituted by a refractive optical system High imaging performance can be maintained in a wide wavelength band. Therefore, if the light reception wavelength range of the imaging device is wide, information other than visible light can be acquired simultaneously. For this reason, since it becomes possible to miniaturize the system of whole system rather than the camera system which mounts an infrared camera device separately, it is preferable.

In the second metal substrate 103, a reflecting surface R11 and a reflecting surface R13 which form a part of the first imaging optical system LO1 and a reflecting surface R21 and a reflection surface which forms a part of the second imaging optical system LO2 R23 is provided.

Moreover, although the metal support stand 4 and the metal support stand 5 are installed in the 2nd metal substrate 103, these can adjust a position and attitude | position independently. The support base 4 is provided with a final reflection surface R15 of the first imaging optical system LO1, and the support base 5 is provided with a final reflection surface R25 of the second imaging optical system LO2. Reflective surface R15 and reflective surface R25 can be adjusted in position and posture via the support 4 and the support 5 so that the imaging surfaces of the image sensor IMG11 and the image sensor IMG12 are appropriately imaged from the respective imaging optical systems It is supported by

The first metal substrate 102 and the second metal substrate 103 are aligned, and both ends thereof are held and fixed to each other by the fixing member 6 and the fixing member 7 to form a unit (unitization). The reflecting surfaces provided on the two metal substrates face each other and are positioned and fixed so as to constitute two Off-Axial optical systems on the left and right. The plurality of reflecting surfaces constituting the first imaging optical system LO1 and the second imaging optical system LO2 have rotationally asymmetric curvatures, and are disposed so as to be tilted so as to bend the reference axis. By providing such a reflective surface, aberration correction can be made easier, and imaging performance can be improved. In the present embodiment, since the reflection surfaces and the aperture surfaces of the left and right imaging optical systems are integrated on the same metal substrate, it is not necessary to adjust the positions of the two imaging optical systems at the time of assembly.

In order to facilitate understanding of the structure of the stereo camera body 101, FIGS. 5 and 6 show an external perspective view of the stereo camera body 101. FIG. FIG. 5 is a perspective view seen from the angle at which the odd-numbered reflecting surface is viewed, and FIG. 6 is a perspective view viewed from the angle at which the even-numbered reflecting surface and the imaging surface of the image sensor are viewed. Note that although the even-numbered reflective surfaces in FIG. 6 and the odd-numbered reflective surfaces in FIG. 5 are at positions not directly visible, the metal substrate on the back side of the position where the reflective surfaces are disposed The numbers of the reflective surfaces are illustrated in the attached.

(Reflecting surface)
Next, the reflective surface provided in the metal support board of embodiment and a metal support stand is demonstrated. Although it is possible to use the surface of the base material of a metal substrate or a metal support as a reflective surface, advanced processing techniques are required to process it into a highly reflective reflective surface with rotationally asymmetric curvature. , Mass production can not be expected, and cost is not realistic.

Therefore, in the present embodiment, as shown in FIG. 4B, a resin portion with high shape accuracy is formed on the surface of a metal substrate or metal support which is a base, and a metal material, for example, is formed on the resin portion. Forming a reflective film to be used as a reflective surface.

FIG. 4B is a schematic cross-sectional view showing the configuration of the reflective surface of the present embodiment, wherein 121 is a base, 122 is a resin part, and 123 is a reflective film. The base material 121 shown in the figure is a support made of a metal substrate or metal. Although the curved surface 121a which imitates the shape of a reflective surface is formed in the base material 121, it is not necessary to necessarily be formed with high shape accuracy, for example, a rough surface may be sufficient. The resin portion 122 is a portion formed of resin at a predetermined position on the base 121 using, for example, an insert molding technique. On the surface of the resin portion 122, a curved surface 122a having a rotationally asymmetric curvature is formed with high accuracy by a method such as transferring a mold surface. The reflective film 123 is formed on the highly accurate curved surface 122a by, for example, vapor deposition of metal.

In view of the method of manufacturing the resin portion and the reflective film, it is difficult to form all the reflective surfaces of the two imaging optical systems on a single metal substrate. Reflective surfaces are arranged on the two supports.

Specifically, as shown in FIG. 7, a metal substrate 102 on which a reflective surface that reflects even-numbered from the incident side is formed, and a metal on which a reflective surface that reflects odd-numbered on the incident side are formed The substrate 103 was a separate frame. Furthermore, the support 4 and the support 5 on which the reflection surface of the final stage is formed are provided. If it is not necessary to adjust the alignment between the imaging optical system and the image sensor based on the position and orientation of the reflection surface of the final stage, the reflection surface of the final stage may be formed on the metal substrate 103 as well. By arranging the even-numbered and odd-numbered reflecting surfaces facing each other on one side of a different frame, formation of a resin portion and formation of a reflecting film are performed using a general manufacturing technique such as insert molding or vapor deposition. It became possible to do with high accuracy and low cost.

(Heat conduction path)
Next, a heat conduction path provided in the stereo camera body 101 of the present embodiment will be described with reference to FIG. 4A.

When a temperature distribution occurs in the stereo camera body due to local heating or cooling from the external environment, expansion or contraction occurs in each part of the unit, and the imaging optical system may not exhibit predetermined performance. However, if each frame of the stereo camera body is made of metal having excellent thermal conductivity, the temperature distribution in each frame can be kept small. The problem is when a temperature difference occurs between the first metal substrate 102 and the second metal substrate 103. In this case, there is a possibility that the relative position, the direction, or the shape of the reflecting surface changes in the relationship between the reflecting surface that reflects odd-numbered and the reflecting surface that reflects even-numbered, and the imaging characteristics may be affected.

Therefore, in the present embodiment, the first metal substrate 102 and the second metal substrate 103 abut each other in good heat conduction at both ends, so that a large temperature difference does not occur between the two metal substrates. That is, the first metal substrate 102 and the second metal substrate 102 are fixed using the fixing member 6 and the fixing member 7 which are heat conductive members so that a plurality of thermally conductive heat conduction paths are formed by direct contact between the metal substrates. The metal substrate 103 is fixed. In FIG. 4A, the first metal substrate 102 and the second metal substrate 103 are in contact at the contact portion 8 and the contact portion 9, and two heat conduction paths for transferring heat well are formed.

The contact between the first metal substrate 102 and the second metal substrate 103 is previously mirror-finished or the like so as to enhance the flatness of the surface so that the contact area becomes sufficiently large at the contact portion 8 and the contact portion 9 It is good to apply In the case where a rough surface having low flatness is brought into contact, the total area of the contact portion 8 and the contact portion 9 is secured so that a substantially sufficient contact area can be secured. That is, in consideration of the flatness, the thermal conductance between the first metal substrate 102 and the second metal substrate 103 is provided by providing a contact portion of a size (total area) that can ensure a necessary contact area. Can be secured large enough.

(Other forms of heat conduction path)
In the embodiment of FIG. 4A, in order to form a thermally conductive heat conduction path between the first metal substrate 102 and the second metal substrate 103, the facing surfaces are in direct contact with each other at the ends of both metal substrates. I did. The embodiment of the present invention is not limited to this, as long as it can form a heat conduction path that sufficiently increases the thermal conductance between the first metal substrate 102 and the second metal substrate 103.
Then, the formation method of the heat conduction path which makes heat conductance large enough, and a formation place are demonstrated below.

First, the method of forming the heat conduction path is not limited to the contact between the surfaces of the metal substrate as described above. For example, the first metal substrate 102 and the second metal substrate 103 may be brought close to or locally in contact with each other, and a thermally conductive member may be disposed around the gap or the contact portion.

As the heat conductive member, for example, silver grease containing heat conductive fine particles, ceramic grease, carbon grease, grease including nano diamond grease, and heat conductive gel may be used. Further, a sheet-like heat conductive material such as a heat conductive sheet or a heat conductive tape may be interposed between the first metal substrate 102 and the second metal substrate 103.

Alternatively, the heat conduction path may be formed by the fixing member itself for fixing the first metal substrate 102 and the second metal substrate 103. For example, after the first metal substrate 102 and the second metal substrate 103 are aligned, a heat conductive adhesive may be used as a fixing member to fix them. From the viewpoint of increasing the thermal conductance between the first metal substrate 102 and the second metal substrate 103, the preferable thermal conductivity of the thermally conductive adhesive is 0.1 [W / mK] or more and 5.0 [5.0 or more]. W / mK] or less. Alternatively, using the fixing member 6 and the fixing member 7 as a metal jig having elasticity with good thermal conductivity and holding them like a clip, the first metal substrate 102 and the second metal substrate 103 are fixed. It is also good. Of course, the metal jig is not limited to an elastic metal member, and may be crimped and fixed using a plastically deformed metal material, or a heat conduction path using a mechanical fixing tool using a metal bolt and nut or the like. May be formed.

Further, the heat conducting member may be provided at a position different from the fixing portion and the contact portion of the metal substrates. For example, a metal foil, a heat conductive sheet, or the like may be used so as to be in contact with the first metal substrate 102 and the second metal substrate 103. Alternatively, the first metal substrate 102 and the second metal substrate 103 may be bonded together by a heat conductive member such as a metal wire or carbon fiber.
The formation place of the heat conduction member is not limited to the end of the metal substrate shown in FIG. 4A, and may be provided inside the end. However, it is preferable that the opening SP11 of the first metal substrate 102 and the opening SP12 of the first metal substrate 102 be provided outside the opening SP11, that is, on the end side of the metal substrate, for ease of mounting.

Further, since the first imaging optical system LO1 and the second imaging optical system LO2 are configured in line symmetry, the heat conduction path is also along the direction in which the first imaging optical system and the second imaging optical system are arranged. It is desirable to arrange them symmetrically. Even if the temperature distribution is generated in the stereo imaging optical system STU, the effect on the stereo measurement is smaller if the temperature distribution is generated symmetrically in the first imaging optical system LO1 and the second imaging optical system LO2.

In addition, as shown in FIG. 4A, the heat conduction member is not limited to a mode in which only one place is provided on the side of the first imaging optical system LO1 and the second imaging optical system LO2, but more heat conduction members may be provided. May be In that case, a plurality of methods for forming the heat conduction path described above may be used in combination.

FIG. 8 is a view schematically showing an example in which a heat conducting member is provided at a plurality of places. For convenience of illustration, only the first imaging optical system LO1 side is shown, but a heat conduction path is also formed on the second imaging optical system LO2 side in line symmetry with this.

In the example shown in FIG. 8, the heat conduction paths are disposed at three locations on the first imaging optical system LO1 side. First, the contact portion 10 in which the first metal substrate 102 and the second metal substrate 103 are in contact with each other is provided outside the opening SP11. That is, the heat conduction path is disposed between the opening SP11 and the end of the metal substrate. Further outside, the metal fixing tool 11 for holding and fixing the end portions of the first metal substrate 102 and the second metal substrate 103 is provided. That is, the heat conduction member including the metal fixture 11 is disposed outside the end of the metal substrate. Further, metal is formed on the outer surface of the first metal substrate 102 and the outer surface of the second metal substrate 103 on the inner side of the opening SP11, that is, on the opposite side to the end of the first metal substrate 102 across the opening SP11. A heat conduction path is provided by a heat conduction member which is a manufactured wire rod 12.

As described above, by arranging the plurality of heat conduction paths in each imaging optical system of the stereo imaging optical system, it is possible to more effectively reduce the occurrence of the temperature distribution.

(Stereo camera device)
Next, a stereo camera device mounted with the stereo camera body 101 will be described. The stereo camera device protects the stereo camera body 101 in order to prevent unnecessary external light, dust, etc. from entering the stereo camera body 101 or to prevent the stereo camera body 101 from directly contacting an external object. Equipped with an enclosure for

In the present embodiment, the stereo camera body 101 is mounted in a double-structured casing in order to enhance the protection performance and to suppress the influence of heating and cooling from the external environment on the stereo camera body 101.

FIG. 9 is a cross-sectional view schematically showing a double-structured case, in which 800 is a stereo camera device, 101 is a stereo camera body, 603 is an inner case, and 605 is an outer case. The stereo camera body 101 is housed in the inner casing 603, and supported and fixed in a state of being separated from the inner casing 603 using a plurality of support members 602. The inner casing 603 is supported and fixed in a state of being separated from the outer casing 605 using a plurality of support members 604. The support member 602 and the support member 604 have a structure in which one end is in contact with the other member at a point or a small area and supported. Thus, the thermal insulation between the external environment and the stereo camera body 101 can be enhanced by providing a plurality of double gaps and using a plurality of supports having a small contact area. For this reason, even if the stereo camera device 800 is locally heated or cooled by direct sunlight or cold air from the outside, it is possible to reduce the thermal influence exerted on the stereo camera body 101.

That is, the housing of this double structure and the heat conduction path provided in the stereo camera body 101 are combined, and the stereo camera device 800 of the present embodiment is also inside the stereo camera body 101 even if it receives heating and cooling from the external environment. Occurrence of the temperature distribution of Even if the temperature environment changes, since the change in the optical characteristics of the stereo imaging optical system is small, it is possible to stably acquire a stereo image reflecting appropriate parallax, and maintain the accuracy of stereo measurement.

Next, FIG. 10 shows a specific configuration of a double-structured casing provided in the stereo camera device 800 of the embodiment. As shown, the inner casing 603 is composed of an inner casing upper member 6031 and an inner casing lower member 6032. The stereo camera body 101 is supported by being sandwiched between the inner casing upper member 6031 and the inner casing lower member 6032. Further, the outer housing 605 is composed of an outer housing upper member 6051 and an outer housing lower member 6052, and the outer housing 605 is supported by the outer housing upper member 6051 and the outer housing lower member 6052 so as to sandwich the inner housing 603. Do.

Attached to an upper portion of the outer housing 605 is an attachment member 606 for mounting the stereo camera device on a windshield of a car or the like. The slope 607 of the attachment member 606 is adjusted in shape so as to be in close contact with the other windshield to be mounted.

FIG. 11 is an external perspective view of the stereo camera device 800, and FIG. 12 is a front view of the stereo camera device 800. As shown in the drawing, the front side of the inner case, the outer case, and the attachment member is provided with an outwardly-opened opening so that external light of a predetermined angle of view is incident on the opening SP11 and the opening SP12 of the stereo camera body. It is done.

13A and 13B are examples of a car in which the stereo camera device 800 is mounted. In both figures, 1000 is a car, 1001 is a windshield, 1002 is a passenger seat. As shown in FIGS. 13A and 13B, the stereo camera device 800 is provided on the passenger seat 1002 side with respect to the windshield 1001 which is a window glass, and more specifically, mounted near the upper edge of the windshield 1001 There is.

The stereo camera device 800 according to the present embodiment is an automobile whose passenger seat is closed as illustrated in FIG. 13A or an automobile whose upper portion of the passenger seat as illustrated in FIG. 13B is open, It can be suitably mounted on a windshield.

In addition, when it is necessary to measure the distance to another vehicle traveling backward and the distance to an object at the time of backward movement when advancing automatic driving and driving assistance, the stereo camera device 800 can be used as a window glass on the rear side. It is also possible to mount it on the passenger seat side of the car. Even in such a case, in the stereo camera device according to the present embodiment, since the reduction in the accuracy of stereo measurement due to direct sunlight, cold air or the like is suppressed, it is possible to obtain highly reliable measurement results.

Embodiments of the present invention are not limited to the above-described embodiments, and can be appropriately modified or combined. For example, the number, shape, arrangement, and the like of free-form surface mirrors that constitute each imaging optical system can be changed as appropriate.

(Production method)
Hereinafter, a method of manufacturing a stereo camera device according to a fourth embodiment of the present invention will be described with reference to the drawings.

FIG. 14 is a flowchart for explaining the manufacturing procedure of the stereo camera device.

First, in step S1, a first metal substrate 102, a second metal substrate 103, a support 4 made of metal, and a support 5 made of metal, which are to be a skeleton of the stereo camera body 101, are formed. As described above, it is difficult to form all the reflection surfaces of the two imaging optical systems on a single metal frame in consideration of the method of manufacturing the resin portion and the reflection film, so in this embodiment, Reflective surfaces are arranged on two metal substrates and two supports. Specifically, as shown in FIG. 7, a first metal substrate 102 on which an even-numbered reflecting surface counting from the incident side is formed and a reflecting surface reflecting on an odd-numbered surface counting from the incident side are formed. The second metal substrate 103 is used as a separate frame.

The metal substrate or the metal support can be manufactured by, for example, a press forming method, a die casting method, a mold forming method such as thixomold, a cutting method, or the like. The metal material to be used includes an alloy containing Mg as a main component. An alloy containing Mg as a main component is advantageous in that it is light in weight and excellent in damping property, and the frame and the support can be manufactured inexpensively, light in weight and highly rigid. Furthermore, when a magnesium alloy is used, the metal barrel member can be manufactured with higher accuracy by the thixomolding method, which is advantageous in increasing the accuracy (surface accuracy and position accuracy) of the reflecting surface. It is.

FIG. 15 shows an injection molding apparatus for manufacturing a metal substrate or a metal support. In the figure, 60 is a mold, 61 is a cavity, 62 is a raw material hopper, 63 is a magnesium alloy chip, 64 is a heater, 65 is a screw, 66 is a cylinder, 67 is a reservoir, 68 is a high speed injection unit, 69 is a nozzle. is there.

When, for example, a magnesium alloy chip 63 is charged into the raw material hopper 62 as a metal material, the metal material is heated and liquefied by the heater 64, pressed by the screw 65, and flows inside the cylinder 66 toward the storage portion 67. Then, the liquid metal at a temperature of 560 ° C. to 630 ° C. stored in the storage portion 67 is ejected from the nozzle 69 by the action of the high-speed injection unit 68. The mold 60 is provided with a cavity 61 conforming to the shape of the metal frame or support to be formed, and the molten metal injected from the nozzle 69 into the cavity 61 is cooled and solidified, and then removed from the cavity Be done.

Returning to FIG. 14, in step S2, the resin portion 122 (see FIG. 4B) to be a base of the reflective surface is formed on each metal substrate and each support manufactured in step S1.

As a method of forming the resin portion, a molding technique using a mold such as an insert molding method, a thermocompression bonding method, or a replica molding method can be used. By preparing a mold that satisfies the shape accuracy of the reflecting surface in advance, even if there is a manufacturing error in the metal substrate or the support, it is possible to absorb the influence and form a highly accurate reflecting surface shape.

16A is a schematic cross-sectional view for showing an example of forming a resin portion on the second metal substrate 103 by insert molding, and FIG. 16B is an insert mold in a direction along line XX in FIG. 16A. It is typical sectional drawing which cut off. In the figure, 71 is an upper mold, 72 is a lower mold, 103 is a second metal substrate, and 611, 613, 621 and 623 are a base of reflective surface R11, reflective surface R13, reflective surface R21 and reflective surface R23 respectively. It is a formed resin part. The second metal substrate 103 is sandwiched between the upper mold 71 and the lower mold 72 and fixed so as to be in close contact with the upper mold 71, and between the second metal substrate 103 and the lower mold 72. A cavity is formed. The inner surface of the lower mold 72 is processed with high precision so that a highly accurate free-form surface shape can be transferred to the resin portion that is the base of each reflective surface. What is shown in the figure is a state in which a resin is injected into each cavity in the mold, and a resin portion 611, a resin portion 613, a resin portion 621 and a resin portion 623 are formed on the second metal substrate 103. When the resin injected into each cavity is cooled and solidified, the mold is opened, the upper mold 71 and the lower mold 72 are separated, and the second metal substrate 103 on which the resin portion is formed is taken out of the mold . Since the reflecting surface R11, the reflecting surface R13, the reflecting surface R21, and the reflecting surface R23 are disposed on the surface on one side of the second metal substrate 103, it is possible to easily form the resin portion by insert molding. The respective resin portions of the first metal substrate 102, the metal support 4 and the metal support 5 can be formed in the same manner.

The material of the resin part is not limited as long as molding by a mold is possible, and in view of ease of molding, durability, and the like among thermosetting resins, thermoplastic resins, and ultraviolet curable resins. Can be chosen. For example, polycarbonate resin, acrylic resin, MS resin, polyolefin resin, etc. can be used. In particular, since a polyolefin resin has low hygroscopicity, it is possible to suppress the change in shape of the reflecting surface due to the moisture absorption of the resin, and a reflective optical unit that achieves high distance measurement accuracy without being affected by the humidity environment using the unit. Can be provided. As a specific example of the polyolefin material, for example, ZEONEX (trade name) manufactured by Nippon Zeon Co., Ltd. can be used. Moreover, it does not necessarily need to be comprised from a single material, and the thing in which the inorganic fine particle etc. were disperse | distributed can also be used for the characteristic improvement as material, or functional provision. In addition, it may be composed of a plurality of layers of different materials.

The resin portion may be provided independently for each of the reflecting surfaces, or may be integrated as a common base of a plurality of reflecting surfaces.

Returning to FIG. 14, in step S3, a reflective film is formed on each metal substrate and each support on which the resin portion is formed in step S2. Although various film-forming methods can be used for formation of a reflective film, the vapor deposition, the sputtering method, etc. which are widely utilized generally can be used. As a material of the reflective film, a metal having a high reflectance such as aluminum or silver may be used, and it is desirable to secure a reflectance of 90% or more for light in a wavelength range of 400 nm to 800 nm. Furthermore, a dielectric film or the like may be added to form a multilayer film for the purpose of surface protection and reflectance improvement.

FIG. 17 is a schematic view for showing an example in which the reflective film 123 is formed on the resin portion 611, the resin portion 613, the resin portion 621 and the resin portion 623 of the second metal substrate 103 by vacuum evaporation. Is a vacuum chamber of a vacuum deposition apparatus, 81 is a deposition source, and 82 is a deposition mask. The second metal substrate 103 is set at a predetermined position in the vacuum chamber 80 whose pressure is reduced to a predetermined degree of vacuum. The predetermined position is a position where the resin portion 611, the resin portion 613, the resin portion 621, and the resin portion 623 can be seen from the vapor deposition source 81. A vapor deposition mask 82 is disposed in the vacuum chamber 80 so that the reflective film material does not adhere to the surface of the second metal substrate 103 other than the resin portion 611, the resin portion 613, the resin portion 621, and the resin portion 623. The reflective film material evaporated from the vapor deposition source 81 is deposited on the free curved surfaces of the resin portion 611, the resin portion 613, the resin portion 621, and the resin portion 623 to form a reflective film 123. Because the reflective surface R11, the reflective surface R13, the reflective surface R21, and the reflective surface R23 are disposed on the surface on one side of the second metal substrate 103, the reflective film of each reflective surface can be formed by a single vapor deposition process It is possible. The respective reflective films of the first metal substrate 102, the metal support 4 and the metal support 5 can be manufactured in the same manner.

The mass productivity may be improved by setting a plurality of metal substrates and supports in a vacuum deposition apparatus so as to form a reflective film on a plurality of members by one deposition. The same applies to the case of using other film forming techniques such as sputtering.

Returning to FIG. 14, in step S4, the first metal substrate 102 and the second metal substrate 103 on which the reflective film 123 is formed in step S3 are aligned and fixed. As shown in FIG. 4A, FIG. 5, and FIG. 6, the reflecting surfaces of the first metal substrate 102 and the second metal substrate 103 face each other and fixed so as to constitute two Off-Axial optical systems on the left and right. The member 6 and the fixing member 7 are used to sandwich and unitize both ends. That is, the reflection surface of the first metal substrate and the reflection surface of the second metal substrate form a stereo imaging optical system including the first imaging optical system and the second imaging optical system. Align the second metal substrate with the second metal substrate. Then, at a position closer to one end of the first metal substrate than the opening SP1 and at a position closer to the other end of the first metal substrate than the opening SP2, the second metal substrate is Fix to metal substrate.

In the present embodiment, in order to obtain a structure in which a large temperature difference does not occur between the first metal substrate 102 and the second metal substrate 103, both metal substrates are fixed by heat conductive members at both ends in step S4. Do. That is, the first metal substrate 102 and the second metal substrate 103 are fixed using the fixing member 6 and the fixing member 7 so that a plurality of thermally conductive heat conduction paths are formed by direct contact between the metal substrates. ing. In FIG. 4A, the first metal substrate 102 and the second metal substrate 103 are in contact with each other at the contact portion 8 and the contact portion 9, and two heat conduction paths for transferring heat well are formed. Although the heat conduction path may be formed in various forms as described above, depending on the form, a heat conduction path may be formed separately from the step S4 of aligning and fixing the metal substrate. You may insert into the process flow of FIG.

Referring back to FIG. 14, in step S5, the image sensor is aligned and fixed to the metal substrate unitized in step S4. That is, in order to enable the image sensor IMG11 to be disposed at the imaging position of the first imaging optical system LO1 and the image sensor IMG12 to be disposed at the imaging position of the second imaging optical system LO2, Fix the image sensor IMG11 and the image sensor IMG12 to.

Next, in step S6, the positions of the metal support 4 and the support 5 on which the reflective surface closest to the image sensor is mounted are adjusted, the optical axes are aligned, and then fixed to the second metal substrate 103. Do. Usually, the optical axis adjustment is performed individually for the first imaging optical system LO1 and the second imaging optical system LO2. FIG. 18 schematically shows a state in which the position and orientation of the reflecting surface R15 are adjusted in order to adjust the optical axis of the first imaging optical system LO1 in step S6. In the first imaging optical system LO1, the opening SP11 as a first opening for taking in external light, the reflecting surface R11, the reflecting surface R12, the reflecting surface R13, the reflecting surface R14, and the image sensor IMG11 are already relative to each other The position is fixed. In order to easily adjust the optical axis, it is advantageous to adjust the optical axis using the reflecting surface R15 closest to the image sensor in the first imaging optical system. Therefore, as shown in FIG. 18, light is made incident from the opening SP11, the image formation state in the image sensor IMG11 is observed while looking at the light image or the sensor output signal, and a support stand made of metal using a jig (not shown) Adjust the position and angle of 4. The metal support 4 whose position and angle are adjusted is fixed to the second metal substrate 103. Similarly to this, also for the second imaging optical system LO2, after adjusting the position and angle of the support 5 made of metal using a jig (not shown) and aligning the optical axis of the reflective surface R25, the support 5 is fixed to the second metal substrate 103. By this process, the stereo camera body 101 including the stereo imaging optical system STU is completed.

Returning to FIG. 14, in step S7, the stereo camera body 101 completed in step S6 is housed in the housing. As shown in FIG. 10, the stereo camera body 101 is supported so as to be sandwiched between the inner casing upper member 6031 and the inner casing lower member 6032, and the outer casing upper member 6051 and the outer casing lower member 6052 from the outside thereof. Support by sandwiching. Then, an attachment member 606 for mounting the stereo camera device on a windshield (windshield) of an automobile or the like is joined to the upper portion of the outer housing 605.

As described above, the stereo camera device mounting the stereo camera body 101 is completed. According to the manufacturing method of the present embodiment, even when heating or cooling is received locally, a reduction in the accuracy of stereo measurement is suppressed, and a compact stereo camera device can be manufactured at low cost. In addition, the manufacturing method which is embodiment of this invention is not restricted to the example mentioned above, It is possible to change suitably and to combine it.

[Example 3]
Next, specific examples will be described.
The metal substrate 102, the metal substrate 103, the support 4 and the support 5 of the stereo camera body 101 were formed by a thixomolding method of Mg alloy (AZ91D). On their inner surfaces, ten reflecting surfaces (five surfaces × 2) are formed to constitute two pairs of imaging optical systems for left and right eyes. Each reflective surface was configured such that a multilayer reflective film mainly composed of an Al film was coated on a layer of a polyolefin resin (NEON ZEON ZEONEX E48R (trade name)) having a thickness of about 1 mm.

The polyolefin resin is bonded to a metal substrate or a support by insert molding, and the multilayer reflective film is formed by vapor deposition. In each of the reflective surfaces, a surface accuracy of at least an in-plane PV value of 2 μm or less is realized.

In addition to bringing the metal substrate 102 and the metal substrate 103 into contact with each other, the heat conduction path is configured such that a metal fixing tool also functions as a heat conduction path. In order to sufficiently increase the thermal conductance between the metal substrate 102 and the metal substrate 103, the metal substrate 102, the metal substrate 103, and the fixture made of metal have a thermal conductivity of 20 W / mK or more and 100 W or more. The following members were used.

Next, the following temperature measurement was performed using the housing of the stereo camera device. First, the stereo camera body 101 was not housed in a double-structured casing provided with an inner casing 603 and an outer casing 605, and was installed near the windshield in an automobile exposed to direct summer sunlight. Then, direct sunlight is irradiated on the upper surface of the outer housing 605, and the temperature of the housing is measured in a state where the lower surface of the outer housing 605 receives cold air of the cooling equipment. As a result, the upper surface of the outer housing 605 is near 100 ° C., the lower surface of the outer housing 605 is 25 ° C., and the distribution of the ambient temperature in the inner housing 603 (difference between the highest temperature and the lowest temperature) is within about 4 ° C. The

Next, the stereo camera body of the above embodiment was housed in the above-described double-structured casing, and distance measurement of an object present 50 m ahead was performed. At that time, it measured in two ways environment.

First, there is almost no temperature distribution outside the casing under normal room temperature environment, and measurement with the distribution of the ambient temperature in the inner casing 603 (hereinafter referred to as ΔT) being 0.5 ° C. went.

Second, as described above, measurements were taken when ΔT = 4 ° C. by placing it in direct sunlight in midsummer and installing it near the windshield of a car in which a cooling system was operating in the car.

The results of the ranging error in the two measurements are shown in Table 1. The distance measurement error indicates how much the difference between the result originally calculated to be 50 m and the result to be calculated. Specifically, the error when calculated as 51 m is + 2%.

Although the error was about ± 5% at ΔT = 0.5 ° C, the error at ΔT = 4 ° C was about ± 7%, but the increase of the error is suppressed and stable distance measurement is possible. Met.

Comparative Example 2
Next, as a comparative example 2, a stereo camera device in which a resin is used as a material of the frame and the heat conduction path is not provided between the frames will be described.

In this comparative example, the shape and layout of the reflecting surfaces of the two pairs of imaging optical systems in the left and right eyes are the same as in Example 3, but unlike Example 3, the material of the frame and the supporting member is Zeon ZEONEX E48R (trade name) was used. That is, the frame and the resin forming the base of the reflective surface were integrally molded by injection molding.

Then, the stereo camera main body was housed in the same double structure as that of the third embodiment, and two distance measurement was performed on an object existing 50 m forward as in the third embodiment.

The results of the ranging error in the two measurements are shown in Table 3. At ΔT = 0.5 ° C., the error was reduced to the same level as that of the example, but in the environment of ΔT = 4 ° C., the error increased significantly. It is considered that the temperature distribution occurs between the frames and the characteristics of the imaging optical system change.

As described above, compared to the comparative example, the error in distance measurement is suppressed even in an environment in which a cooling facility is operating in a car exposed to direct sunlight in midsummer as compared with the comparative example, and stable distance measurement is It was possible.

According to the reflective optical element of the present invention, it is possible to provide a lightweight and highly damping reflective optical system.

Japanese Patent Application No. 2017-161366 filed on Aug. 24, 2017, Japanese Patent Application No. 2018-071407 filed on Apr. 3, 2018, filed Apr. 3, 2018 Claims the priority of Japanese Patent Application No. 2018-071408 and Japanese Patent Application No. 2018-153927 filed on Aug. 20, 2018, the contents of which are incorporated herein by reference. It is a department.

1 substrate 2 resin layer 3 reflective film M1 to M6 functional unit (mirror)
R2 to R8 function unit (mirror)
21 and 31

base parts

24 and 34 connection part 101 stereo camera body 102 first metal substrate 103 second metal substrate 4 metal support base 5

metal support base

6, 7 fixing member 8, 9 contact part 11 Fastener 12 Metal wire rod 121 Base material 121a Curved surface 122 Resin part 123 Reflective film 602 Support member 603 Inner case 604 Support member 605 Outer case 606 Attachment member 800 Stereo camera device 1000 Automobile 1001 Front glass 1002 Passenger seat IMG1, IMG2 , IMG11, IMG12 image sensor LO1 first imaging optical system LO2 second imaging optical system R11 to R15, R21 to R25 reflective surface SP1, SP2, SP11, SP12 aperture STU stereo imaging optical system

Claims

A reflective optical element comprising a resin layer having an optical surface on a metal substrate, and a mirror provided with a reflective film on the optical surface,
In the metal substrate, a first opening for taking light into a first imaging optical system, a plurality of mirrors of a first imaging optical system for reflecting light taken in from the first opening, and A second opening for taking light into two imaging optical systems and a plurality of mirrors of the second imaging optical system for reflecting the light taken in from the second opening are provided, and the metal substrate is Mg What is claimed is: 1. A reflective optical element comprising an alloy containing as a main component.
The reflective optical element according to claim 1, wherein the alloy containing Mg as a main component is a Mg—Li alloy.
The thickness of the said resin layer is 20 micrometers-2000 micrometers, The reflective optical element of Claim 1 or 2 characterized by the above-mentioned.
The reflective optical element according to any one of claims 1 to 3, wherein the resin layer contains an olefin resin.
A stereo camera device comprising the reflective optical element according to any one of claims 1 to 4.
The metal substrate comprises a first metal substrate and a second metal substrate,
The first metal substrate has a first aperture for taking light into a first imaging optical system, a plurality of mirrors that are a part of the first imaging optical system, and a second imaging optical system. A second aperture for taking in and a plurality of mirrors that are part of the second imaging optical system;
The second metal substrate is provided with a plurality of other mirrors which are a part of the first imaging optical system, and a plurality of other mirrors which are a part of the second imaging optical system. Yes,
The plurality of mirrors provided on the first metal substrate and the plurality of other mirrors provided on the second metal substrate are disposed to face each other, and the first image forming optical system and the second image formation are provided. A stereo imaging optical system consisting of an optical system is formed,
The first metal substrate and the second metal substrate are fixed to each other at a position closer to the end of the first metal substrate than the first opening and the second opening to form a unit. Yes,
A thermally conductive member is provided at a portion where the first metal substrate and the second metal substrate are in contact with each other.
The stereo camera device according to claim 5, characterized in that:
The plurality of heat conductive members are disposed symmetrically along the direction in which the first imaging optical system and the second imaging optical system are arranged,
The stereo camera apparatus according to claim 6,
The thermally conductive member includes grease containing a thermally conductive material interposed between the first metal substrate and the second metal substrate.
The stereo camera device according to claim 6 or 7, characterized in that:
The thermally conductive member includes a sheet-like thermally conductive material disposed between the first metal substrate and the second metal substrate.
The stereo camera device according to claim 6 or 7, characterized in that:
The heat conductive member includes a heat conductive adhesive for fixing the first metal substrate and the second metal substrate.
The stereo camera device according to claim 6 or 7, characterized in that:
The heat conductive member includes a metal jig for fixing the first metal substrate and the second metal substrate.
The stereo camera device according to claim 6 or 7, characterized in that:
And a thermally conductive member coupled to the first metal substrate and the second metal substrate at a position different from the position where the first metal substrate and the second metal substrate are fixed.
The stereo camera device according to any one of claims 6 to 11, characterized in that
The mirror is a free curved mirror having a resin part disposed on the metal substrate and having a free curved surface formed thereon, and a reflective film coated on the free curved surface of the resin part.
The stereo camera device according to any one of claims 6 to 12, characterized in that
The apparatus further includes an inner case and an outer case, wherein the unit is supported at a distance from the inner case, and the inner case is supported at a distance from the outer case.
The stereo camera device according to any one of claims 6 to 13, characterized in that
With window glass,
The stereo camera device according to any one of claims 5 to 14, which is installed closer to the passenger seat than the window glass.
A car characterized by