JP2014002222A - Camera unit and range-finding device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a camera unit that secures reliability without lowering a production yield even if there is a difference in a linear expansion coefficient between an imaging lens and an imaging element and is also proof against an environment temperature change.SOLUTION: The camera unit is configured to comprise: a plurality of imaging lenses 111 that image light reflected on a subject; supporting means 113 that supports the imaging lenses 111 on one plane and includes a light path of light passing through each of the imaging lenses 111; and a plurality of pieces of imaging means 114 that are fixedly adhered to the other plane facing the one plane of the supporting means 113 and photograph an image relating to the subject on the basis of the light passing through the light path. The supporting means 113 is formed by material that has the almost same linear expansion coefficient as that of main material of the imaging means 114, and the imaging lenses 111 are held on one plane of holding means in a non-adhesion manner.

Description

  The present invention relates to a camera unit applicable to a distance measuring device using the principle of triangulation, and a distance measuring device using the same.

Conventionally, a small distance measuring device that can obtain a distance to a distance measuring object based on triangulation is known. In such a distance measuring apparatus, an imaging optical system for forming an image of a subject as a distance measuring object on each of two light receiving elements is arranged so that the respective light receiving optical axes are parallel to each other and photographed by each light receiving element. The distance to the subject is measured on the basis of the deviation between the images detected by comparing the obtained images.
That is, when the distance between the optical axes of the two lenses, called the baseline length, is D, the distance from the subject to the lens is L, and the focal length of the lens is f, and L >> f, the following [Equation 1] holds. . Therefore, since the baseline length D and the focal length f of the lens are design values and are known, the distance L to the subject can be calculated by detecting the parallax δ from [Equation 1].
[Formula 1] L = D · f / δ
Conventionally known small image pickup devices using the principle of triangulation include at least a lens constituting an imaging optical system, an image pickup device as a light receiving element for taking a subject image, and a back focus distance of the lens. An image distance holding member is required.
As the lens, a resin lens using a resin material and a glass lens using a glass material are generally used. Their linear expansion coefficients are several tens of ppm / ° C. or more for resin materials and 10 ppm / ° C. or more for glass materials.

Moreover, the image sensor is generally made on a silicon wafer using a semiconductor technology, and the linear expansion coefficient of the image sensor is about 3 ppm / ° C.
There is a problem that a large distortion occurs due to the difference in linear expansion coefficient between the lens and the image sensor, and the manufacturing yield is lowered.
In addition, since the base line length D and the focal length f of the lens in [Equation 1] described above change depending on the environmental temperature, the ranging accuracy is lowered, and the reliability line as a ranging device is impaired. Also occurs.
In order to deal with such a problem, Patent Document 1 discloses that an imaging unit that acquires an image of a subject as a distance measuring object includes a pair of imaging lenses (lens array) and an optical sensor array that constitute an imaging optical system. By forming the lens array holding member that also serves as the imaging distance holding member and the optical sensor array holding member from the same material (a non-hygroscopic plastic such as an amorphous cycloolefin polymer), the ambient temperature There has been proposed a distance measuring device that eliminates the deviation between the imaging lenses and the sensor array due to humidity and improves the distance measuring accuracy.

However, in Patent Document 1, the linear expansion coefficient of the plastic material (resin material) that is the material of the holding member of the lens array and the holding member of the sensor array is larger than that of the image sensor (photosensor) material. Because it is about an order of magnitude higher, thermal fatigue damage between the imaging distance holding member (lens array holding member and sensor array holding member) / imaging element (damage due to temperature change, cracking and peeling being the main damage) It could not be completely removed.
The distortion caused by this thermal fatigue damage has also affected the characteristics of the image sensor.
The present invention has been made in view of the above problems, and an object of the present invention is to provide a highly reliable camera unit that is resistant to environmental temperature changes even when there is a difference in linear expansion coefficient between the imaging lens and the imaging device. And

  In order to solve the above-described problems, the present invention provides a plurality of imaging lenses that form an image of light reflected by a subject, and each of the imaging lenses held at a portion facing the subject. A first holding unit having a first holding unit and having a plurality of openings through which the light transmitted through the imaging lenses held by the first holding unit passes, and the first holding unit; A plurality of imaging means that are joined to a part facing the holding part and image the light of the subject by imaging the light that has passed through each opening, and the first holding means includes The camera unit is formed of a material having substantially the same linear expansion coefficient as the main material of the image pickup means, and each of the image pickup lenses is held by the first holding portion of the first holding means in a non-adhesive manner. To do.

  With the above configuration, according to the present invention, a camera that suppresses a decrease in distance measurement accuracy due to the ambient temperature and reduces peeling and distortion between members caused by the difference in linear expansion coefficient is achieved. Units can be provided.

The figure explaining the basic principle of ranging by the triangulation applicable to embodiment of this invention. FIG. 3 is a cross-sectional view illustrating a configuration example of a distance measuring device according to the first embodiment. The figure which shows the structure for incorporating an imaging lens in the imaging lens holding member in 1st Embodiment. Sectional drawing which shows the manufacturing process of the imaging part (camera unit) in the distance measuring device which concerns on 1st Embodiment. Sectional drawing which shows the structure of the camera unit which concerns on the 2nd Embodiment of this invention. The figure which shows the structure for incorporating an imaging lens in an imaging lens holding member and an imaging distance holding member in 2nd Embodiment. Sectional drawing which shows the structure of the ranging apparatus which concerns on the 3rd Embodiment of this invention. The figure which shows the structure for incorporating an imaging lens in the imaging distance holding member in 3rd Embodiment. Sectional drawing which shows the structure of the ranging apparatus concerning the 4th Embodiment of this invention. The system block diagram using the distance measuring device of this invention.

Embodiments of the present invention will be described below in detail with reference to the drawings.
FIG. 1 is a diagram for explaining the basic principle of distance measurement by triangulation applicable to the embodiment of the present invention.
In FIG. 1, a case is considered in which light from a subject 101 is photographed by arranging two cameras (first camera 102a and second camera 102b) having the same optical system.
The first camera 102a and the second camera 102b are fixed on the base substrate 106, for example, and are arranged so that their optical axes are parallel to each other.
In the first camera 102a, the first subject image 107a obtained through the first lens 103a is projected onto the first image sensor 104a by shifting the same point on the first subject image from the optical axis by δ1. Light is received by a large number of light receiving elements (pixels) in an imaging region on one image sensor 104a and converted into an electrical signal.
Similarly, in the second camera 102b, the second subject image 107b obtained through the second lens 103b is projected onto the second image sensor 104b with the same point on the subject image shifted from the optical axis by δ2. Light is received by a large number of light receiving elements (pixels) in the image pickup area on the second image pickup element 104b and converted into an electric signal.

The parallax δ (δ1, δ2) is generated as a shift in a direction perpendicular to the two optical axes in a plane including the two optical axes. Therefore, when the arrow direction of the subject 101 is a plus coordinate and the opposite direction is a minus coordinate, the subject image 107a is displaced by δ1 in the plus direction and the subject image 107b is displaced by δ2 in the minus direction, so that δ = δ1-(− δ2).
[Formula 1] L = D · f / δ
Accordingly, since the baseline length D and the focal length f of the lens are design values and are known, the distance L to the subject can be calculated by detecting the parallax δ.

The configuration of the camera unit applicable to the distance measuring device that performs the above-described stereo distance measurement will be described below.
In the following embodiments, a stereo camera unit having two cameras used in the distance measuring device is described as an example. However, the present invention is not limited to this, and a compound eye camera having three or more cameras or a single camera unit is used. Needless to say, the present invention is also applicable to a monocular camera having a camera.

[First Embodiment]
FIG. 2 is a cross-sectional view showing a configuration example of the camera unit according to the first embodiment of the present invention.
The camera unit shown in FIG. 2 includes a distance measurement arithmetic circuit, an electrical board 116 provided with a circuit including a digital signal processor (DSP), and a plurality of, for example, mounted on electrodes 119 provided on the electrical board 116. Two solid-state imaging devices (first solid-state imaging device 117a and second solid-state imaging device 117b), and imaging devices (first imaging device provided on one surface of the first solid-state imaging device 117a and second solid-state imaging device 117b) An imaging lens (first imaging lens 111a, second imaging lens 111b) for forming a subject image on the imaging element 114a and the second imaging element 114b), and a holding unit having the imaging lens on the subject side ( While being held by 113 </ b> A, the imaging lens (first imaging lens 111 a and second imaging lens 111 b) to the solid-state imaging device (first solid-state imaging device 11). a, an imaging distance holding member 113 as a first holding means which is a member for holding the imaging distance to the second solid-state imaging device 117b), and the imaging lens (first And an imaging lens holding member 112 as a second holding means that is a member that sandwiches and fixes the imaging lens 111a and the second imaging lens 111b).

In FIG. 2, the imaging distance holding member 113 includes an imaging lens (first imaging lens 111a and second imaging lens 111b) and a solid-state imaging device (first solid-state imaging device 117a and second solid-state imaging device 117b). Are provided between the formation surfaces of the imaging elements 114a and 114b.
The optical axis centers of the first imaging lens 111a and the second imaging lens 111b are aligned so as to coincide with the centers of the imaging elements 114a and 114b.

As the imaging lens (the first imaging lens 111a and the second imaging lens 111b), for example, a glass lens or a resin lens can be used. The glass lens is more expensive than the resin lens and disadvantageous in terms of cost, but has a smaller linear expansion coefficient than the resin lens and is effective in ensuring high measurement accuracy. As an advantage.
In the present embodiment, the imaging lenses (the first imaging lens 111a and the second imaging lens 111b) are formed by press-molding a glass material.
As the optical glass material of the first imaging lens 111a and the second imaging lens 111b, for example, K-VC78 manufactured by Sumita Optical Glass Co., Ltd. can be used.
Of course, the first imaging lens 111a and the second imaging lens 111b are not limited to K-VC78, and any optical glass material can be selected according to the optical design.
Furthermore, the imaging lens holding member 112 and the imaging distance holding member 113 are made of the same member, and are both made of silicon in this embodiment.

Further, in the solid-state image pickup device (first solid-state image pickup device 117a, second solid-state image pickup device 117b) as the image pickup means, the opposite of the light receiving portion of the image pickup device (first image pickup device 114a, second image pickup device 114b). The electrodes of the imaging elements 114a and 114b are drawn out by TSV (Through Silicon Via) on the side, and solder balls 118 are arranged on the drawn electrodes.
That is, the solid-state imaging device 117 (first solid-state imaging device 117a, second solid-state imaging device 117b) is mounted on the electrode 119 on the electrical board 116 via the solder balls 118 via SMT (Surface Mount Technology).
Further, for the purpose of ensuring the reliability of the joining with the solder balls 118, an underfill is provided between the solid-state imaging device (the first solid-state imaging device 117 a and the second solid-state imaging device 117 b) joined with the solder ball 118 and the electrical board 116. The agent 120 is formed.

In the first solid-state imaging device 117a and the second solid-state imaging device 117b, the first imaging device 114a and the second imaging device 114b are arranged in a line on the same plane with respect to the imaging device surface, respectively. The distances between the centers of 114a and 114b are the distances that are the base line length D described in FIG.
As the solid-state imaging device (the first solid-state imaging device 117a and the second solid-state imaging device 117b), a CCD (Charge Coupled Device) or a CMOS (Complementary Metal Oxide Semiconductor) is used. However, in this embodiment, CMOS is adopted.

The two imaging lenses (the first imaging lens 111a and the second imaging lens 111b) have a distance between their centers that is the distance of the baseline length D (FIG. 1), and the optical axes of the imaging lenses 114a and 114b, respectively. It is arranged so as to be orthogonal to the surface of
In addition, the imaging distance holding member 113 described above is formed on the silicon wafer having a thickness that can define the back focus of the first imaging lens 111a and the second imaging lens 111b from the first imaging lens 111a and 111b to the solid-state imaging device 117a. Two openings (through holes) 113a and 113b are provided for securing an optical path up to 117b.
The centers of the openings 113a and 113b are configured to coincide with the optical axes of the first imaging lens 111a and the second imaging lens 111b.
As the material of the imaging distance holding member 113, silicon is used as in the main material of the solid-state imaging device (the first solid-state imaging device 117a and the second solid-state imaging device 117b).

The solid-state imaging devices (the first solid-state imaging device 117a and the second solid-state imaging device 117b) have the imaging devices 114a and 114b for the purpose of protecting the imaging devices 114a and 114b (preventing scratches, adhering dust, etc.). Cover glass 115a, 115b is provided on the light receiving part side.
The cover glass (cover glasses 115a and 115b) used here is preferably made of a material close to the linear expansion coefficient of the solid-state imaging devices 117a and 117b. In this example, AF45 (manufactured by shot) having a linear expansion coefficient of α = 4.5 ppm / ° C. was used.
Since the imaging distance holding member 113 is made of silicon having the same linear expansion coefficient as that of the solid-state image sensor (including the cover glass 115), the solid-state image sensor (the first solid-state image sensor 117a and the second solid-state image sensor). It is easy to secure the bonding strength between the element 117b) and the imaging distance holding member 113, and it is possible to reduce thermal fatigue due to a difference in linear expansion coefficient between the members.
By making the material of the imaging distance holding member 113 sandwiched between the pair of imaging lenses and the pair of imaging elements substantially the same as the linear expansion coefficient of the imaging element 117, distortion generated between the imaging distance holding member and the imaging element is reduced. It is possible to avoid deterioration of the characteristics of the image sensor.
Thereby, the reliability of the distance measuring apparatus using this stereo camera can be improved.

In addition, since silicon having a small linear expansion coefficient is applied to the imaging distance holding member 113, the dependence of the baseline length on the environmental temperature is reduced, and the dependence of the distance measurement on the environmental temperature can be suppressed.
Furthermore, since the imaging lens holding member 112 and the imaging distance holding member 113 are opaque to visible light, light between adjacent cameras (a combination of an imaging lens, an imaging distance holding member, and an imaging device) can be used. Crosstalk can be prevented.
Since the silicon constituting the imaging lens holding member 112 and the imaging distance holding member 113 is opaque to the visible light region, it is possible to cross the imaging light flux without providing a separate light shielding member for the imaging distance holding member 113. It functions as a light shielding member that prevents talk, and the imaging lens holding member 112 functions as a diaphragm. Therefore, the number of manufacturing steps for forming the light shielding structure can be reduced.

FIG. 3 is a diagram illustrating a structure for incorporating the imaging lens into the imaging lens holding member in the first embodiment, and FIG. 3A is a front view of the imaging surface of the imaging lens holding member before the imaging lens is assembled ( (a) and AA ′ cross-sectional views (b) and (B) are image plane side front views of the imaging lens, and (C) is an image plane side front view of the imaging lens holding member after the imaging lens is assembled (a). ) And AA ′ cross-sectional view (b).
As shown in FIG. 3A, grooves 112a and 112b are formed in the second holding portion 112A of the imaging lens holding member 112 along the outer shapes of the first imaging lens 111a and the second imaging lens 111b. The first imaging lens 111a and the second imaging lens 111b are fitted into the groove and assembled.
A groove that matches the outer shape of the imaging lens may be formed on the imaging distance holding member 113 side, and the imaging lens may be fitted into the groove. Further, a groove for fitting the imaging lens may be formed in both the imaging lens holding member 112 and the imaging distance holding member 113.
As shown in FIG. 3 (B), the collars 111c of the first image pickup lens 111a and the second image pickup lens 111b are provided at three locations, and when assembled as shown in FIG. 3 (C). The first imaging lens 111a and the second imaging lens 111b are designed not to rotate in the groove.
Besides this shape, the first imaging lens 111a and the second imaging lens 111b can be freely designed so as not to rotate.

FIG. 4 is a cross-sectional view illustrating a manufacturing process of the imaging unit (camera unit) in the distance measuring apparatus according to the first embodiment.
In FIG. 4, the same components as those in FIG. 2 are denoted by the same reference numerals as those in FIG.
First, an imaging distance holding member 113 as shown in FIG. 4A is prepared.
The imaging distance holding member 113 has two openings (through holes) 113a and 113b. The distance between the centers of the two openings 113a and 113b is designed to be the distance of the base line length D (FIG. 1). As described with reference to FIG. 2, a silicon material is used as the base material of the imaging distance holding member 113.
As described above, since the base silicon is an opaque member in the visible light region, it can also serve as a light shielding structure that shields light between the adjacent imaging elements 114a and 114b. This eliminates the need for a separate light shielding structure, leading to a reduction in manufacturing cost.

Next, as shown in FIG. 4B, the centers of the first image sensor 114a and the second image sensor 114b are aligned with the centers of the openings 113a and 113b of the imaging distance holding member 113. Then, the solid-state imaging devices 117a and 117b are bonded and fixed.
The solid-state imaging device (first solid-state imaging device 117a, second solid-state imaging device 117b) protects the imaging devices (first imaging device 114a, second imaging device 114b) (scratch prevention, dust adhesion, etc.). For this purpose, a cover glass 115 is provided on the light receiving portion side of the image sensors 114a and 114b, and the surface (incident surface) of the cover glass 115 is bonded and fixed to the imaging distance holding member 113.

The solid-state image sensors 117a and 117b have TSVs (Through Silicon Vias) formed on the opposite sides of the image sensors 114a and 114b. The solder balls / BGA (Ball Grid Array) 118 described above are formed on the electrode surfaces. Is formed.
As the BGA 118, for example, a tin (Sn), silver (Ag), or copper (Cu) based alloy that does not contain lead can be used.
As a component of the alloy, Sn-30% Ag-0.5% Cu is the mainstream. However, if the silver content increases, the cost increases. Therefore, Sn-10% Ag having a low silver composition is used to reduce the cost. -0.7% Cu, Sn-0.3% Ag-0.7% Cu, Sn-0.1% Ag-0.7% Cu, or the like may be used.

Next, as shown in FIG. 4C, the first imaging lenses 111 a and 111 b are placed on the imaging distance holding member 113 and the imaging lens holding member 112 is bonded onto the imaging distance holding member 113. Put the lid on.
In the bonding process shown in FIGS. 4B to 4C, an adhesive that can withstand a lead-free reflow process at about 270 ° C. is preferable, and a heat-resistant epoxy adhesive, a modified silicone adhesive, and the like are suitable. Yes. Here, Alemco Bond 570 (Alemco Products, USA), which is a high heat-resistant epoxy adhesive, was used.
Alemcobond 570 is a one-component adhesive having a heat resistant upper limit of 316 ° C. It is a highly productive material that can withstand lead-free reflow and is easy to handle due to its one-part nature. The thickness of the adhesive was adjusted to 0.2 mm.

Finally, as shown in FIG. 4D, the BGA 118 in the component made in FIG. 4C is aligned with the image sensor substrate electrode pad 119 on the electrical board 116 and passed through a reflow furnace to electrically Connected.
Further, in order to improve the reliability of the electrical connection portion, an underfill agent 120 was poured and the periphery of the BGA 118 was fixed. This is also as described in FIG.
In the present embodiment, the imaging lens (the first imaging lens 111a and the second imaging lens 111b) is not bonded and fixed to the imaging lens holding member 112 or the imaging distance holding member 113.
As described with reference to FIG. 3, the imaging lens is held in a state where the imaging lens is fitted in the grooves 112 a and 112 b provided in the imaging lens holding member 112 (or the grooves provided in the imaging distance holding member 113). By sticking the member 112 to the imaging distance holding member 113, the imaging lenses (the first imaging lens 111a and the second imaging lens 111b) are placed between the imaging distance holding member 113 and the imaging lens holding member 112. Hold.
In the present embodiment, the imaging lenses (the first imaging lens 111a and the second imaging lens 111b) are not bonded to the imaging lens holding member 112 or the imaging distance holding member 113. It is possible to suppress the occurrence of lens distortion caused by the difference in linear expansion coefficient due to the difference in material from the imaging lens.

Further, as described above, the imaging lenses 111a and 111b having different linear expansion coefficients and the imaging distance holding member 113 have a structure that does not need to be bonded and bonded, so that imaging caused by ambient temperature (environmental temperature change) occurs. Generation of distortion between the lens / imaging distance holding member and prevention of peeling can be achieved.
In the first embodiment, the two imaging lenses, that is, the first imaging lens 111a and the second imaging lens 111b are physically separated, and the imaging lens holding member 112 and the imaging distance holding member 113 are separated. Therefore, the environmental temperature change of the distance between the imaging lenses is determined by the linear expansion coefficient of the imaging lens holding member 112 and the imaging distance holding member 113.
Since silicon having a small coefficient of linear expansion is applied to both the imaging lens holding member 112 and the imaging distance holding member 113, the dependence of the baseline length D on the environmental temperature is reduced, and the dependence of the distance measurement on the environmental temperature is suppressed. Measurement accuracy can be improved.
In addition, since the two imaging lenses are physically divided into two individual lenses and assembled, even if materials having different linear expansion coefficients are used, the influence due to temperature change between members can be ignored.

The effect of using two single lenses that are physically separated (independent) instead of the lens array will be described in detail with reference to FIGS.
For example, in the example of FIG. 2, when the base line length D of the pair of imaging lenses 111a and 111b is 5 mm and the aperture Φ of each lens is 1 mm, the lens array direction is 6 mm when the two imaging lenses are integrated (lens array). It becomes the above length.
The joint surface length length A of the imaging lenses 111a and 111b and the imaging distance holding member 113 is 6 mm, the linear expansion coefficient α1 of the imaging distance holding member 113 is 3 ppm / ° C., and the linear expansion coefficient α2 of the imaging lens is 70 ppm / When the temperature change Δt is 10 ° C., the following [Expression 2] and [Expression 3] indicate that a difference of about 4 μm occurs when the temperature change Δt is 10 ° C. when the two imaging lenses are integrated. It will be.
[Formula 2] A × α1 × Δt = 0.18 μm
[Formula 3] A × α2 × Δt = 4.2 μm
On the other hand, when the two imaging lenses are made into a single lens that is physically divided, the length in the lens array direction is equal to or longer than 1 mm in terms of the lens aperture Φ.

The joint surface length length A of the imaging lenses 111a and 111b and the imaging distance holding member 113 is 1 mm, the linear expansion coefficient α1 of the imaging distance holding member is 3 ppm / ° C., and the linear expansion coefficient α 2 of the imaging lens is 70 ppm / ° C. When the temperature change Δt is 10 ° C.,
From the following [Expression 4] and [Expression 5], when the two imaging lenses are made into a single lens that is physically divided, a difference of 0.67 μm occurs at a temperature change Δt of 10 ° C.
[Formula 4] A × α1 × Δt = 0.03 μm
[Formula 5] A × α2 × Δt = 0.7 μm
Therefore, when the temperature change Δt is 10 ° C., the difference in length between the imaging lens and the imaging distance holding member is about 4 μm when the two imaging lenses are integrated, whereas the two imaging lenses are physically It can be seen that when the single lens is divided into 0.67 μm.

Since the two imaging lenses are physically separated and held by the imaging distance holding member, the temperature characteristic of the distance between the two imaging lenses is almost determined by the temperature characteristic of the imaging distance holding member 113.
In this embodiment, the linear expansion coefficient of the imaging distance holding member is about 3 to 5 ppm / ° C., which is substantially the same as the linear expansion coefficient of the image sensor, and the linear expansion of the plastic material (resin material) in Patent Document 1 described above. Compared to the coefficient, it is about one order of magnitude smaller. Therefore, the change due to the ambient temperature of the distance between the pair of imaging lenses can be reduced, and the ranging accuracy can be improved.

(1) Improvement of ranging accuracy Patent Document 1 describes that the imaging lens, the holding member for the imaging lens, and the holding member for the optical sensor array are formed of the same material made of non-hygroscopic plastic. It is described that an amorphous cycloolefin polymer is used as the non-hygroscopic plastic.
Therefore, the distance measurement accuracy due to the environmental temperature change of the base line length D (see FIG. 1) is determined by the linear expansion coefficient of the holding member of the imaging lens and the holding member of the optical sensor array. The linear expansion coefficient of amorphous cycloolefin polymer is generally about 70 ppm / ° C.
For example, the base line length D of the pair of first lens 103a and the second lens 103b is 5 mm, the distance L from the center of the first lens 103a and the second lens 103b to the subject is 5 m, the first lens 103a, If the focal length f of the second lens 103b is 5 mm, the parallax δ from [Equation 1] is
[Formula 6] δ = D · f / L = 5 μm
It becomes.

That is, in this distance measuring apparatus, when a parallax δ of 5 μm is detected, the distance L is recognized as 5 m.
For example, in the case where plastic is used for the imaging distance holding member as in Patent Document 1 described above, if the plastic linear expansion coefficient α is 70 ppm / ° C., and the temperature change Δt is 10 ° C.,
[Formula 7] D × α × Δt = 3.5 μm
This is equivalent to changing the parallax by 3.5 μm.
As a result, if the temperature change is 10 ° C., a distance measurement error as large as 70% (= 3.5 μm / 5 μm) occurs even if the same distance of 5 m is measured.

On the other hand, in the case of the present invention, the imaging distance holding member 113 (corresponding to the positions of the imaging lens holding member and the photosensor array holding member of Patent Document 1) is substantially the same as the linear expansion coefficient of the image sensor. Since it becomes 3-5 ppm / ° C., the coefficient of linear expansion can be reduced as compared with the conventional example, so that the dependence of measurement accuracy on environmental temperature change can be reduced, and distance measurement can be performed with high accuracy.
When the material substantially the same as the linear expansion coefficient of the image sensor (the first image sensor 104a and the second image sensor 104b) is used for the imaging distance holding member 113 as in the present invention, the linear expansion coefficient α is 3 ppm. Assuming that the temperature change Δt is 10 ° C.
[Formula 8] D × α × Δt = 0.15 μm
This is equivalent to a change in parallax of 0.15 μm.
As a result, if the temperature change is 10 ° C., even if the same distance of 5 m is measured, the distance measurement error is 3% (= 0.15 μm / 5 μm).
Furthermore, the imaging lens (glass lens or plastic lens) having a larger linear expansion coefficient than the imaging device uses two physically separated single lenses, and the temperature dependence of the distance between the lenses is an imaging distance holding member. Since the structure is almost determined by the linear expansion coefficient, the measurement accuracy can be improved.

(2) Reduction of peeling between members caused by the difference in linear expansion coefficient In Patent Document 1, the imaging lens, the holding member for the imaging lens, and the holding member for the photosensor array are not hygroscopic. It is made of the same material made of plastic. Further, as the non-hygroscopic plastic, an amorphous cycloolefin polymer is used.
Since the optical sensor array is a CCD, it is made on a silicon wafer, so its linear expansion coefficient is about 3 ppm / ° C.
Amorphous cycloolefin polymers include heat-resistant polycarbonate and ZEONEX (registered trademark). Their linear expansion coefficient is about 70 ppm / ° C., which is about 20 times larger than the linear expansion coefficient of the matrix of the optical sensor array.
Therefore, if the difference in coefficient of linear expansion between members is large, thermal fatigue damage will occur. In a device composed of parts having different coefficients of thermal expansion, the problem of thermal stress accompanying temperature change cannot be avoided. When restraint is strengthened to suppress thermal deformation, a large stress works, and destruction starts from a structurally weak place. On the other hand, if the constraint is weakened, a positional deviation occurs between the lens and the solid-state imaging device, resulting in a problem that measurement reproducibility cannot be obtained, or a problem that damage starts from a place where the constraint is weak.

In the present invention, the imaging distance holding member (corresponding to the positions of the holding member of the imaging lens and the holding member of the optical sensor array in Patent Document 1) is made substantially the same as the linear expansion coefficient of the image sensor, thereby forming the imaging distance. Thermal fatigue damage between the holding member and the image sensor is reduced.
Furthermore, the imaging lens (glass lens or plastic lens) having a larger linear expansion coefficient than the imaging device uses two physically separated single lenses, and the temperature dependence of the distance between the lenses is an imaging distance holding member. Since the structure is almost determined by the linear expansion coefficient, the measurement accuracy can be improved.
However, since the imaging lens and the imaging distance holding member have a large difference in linear expansion coefficient, thermal fatigue damage is reduced by using two physically separated single lenses. In addition, the imaging lens holding member and the imaging distance holding member, which have a shape to be dropped according to the outer shape of the imaging lens, are held and the imaging lens and the imaging distance holding member are not bonded and fixed. Separation between members due to changes can be avoided.

[Second Embodiment]
FIG. 5 is a cross-sectional view showing a configuration of a camera unit according to the second embodiment of the present invention.
In the present embodiment, ceramic is used for the imaging distance holding member and the imaging lens holding member.
The solid-state imaging device 217 (first solid-state imaging device 217a, second solid-state imaging device 217b) has two imaging devices 214a and 214b arranged in a line on the same plane with respect to the imaging device surface. They are placed at a distance so that the center-to-center distance is the baseline length.
As the solid-state imaging device (first solid-state imaging device 217a, second solid-state imaging device 217b), a CCD or a CMOS can be used as in the first embodiment shown in FIG. Uses CMOS.
The two imaging lenses (the first imaging lens 211a and the second imaging lens 211b) use the distance between the centers as the distance of the base line length D (FIG. 1), and each imaging lens (the first imaging lens 211a and the second imaging lens 211b). The optical axis of the imaging lens 211b) is disposed so as to be orthogonal to the surface of the imaging element (first imaging element 214a, second imaging element 214b).

As the imaging lenses 211a and 211b, for example, glass lenses and resin lenses can be used as in the first embodiment.
The imaging distance holding member 213 serving as the first holding unit is configured from the imaging lens (the first imaging lens 211a and the second imaging lens 211b) disposed in the first holding unit 213A on the subject side to the solid-state imaging device (first imaging element). It is an imaging distance holding member for holding the imaging distance to the solid-state imaging device 217a and the second solid-state imaging device 217b), and has openings (through holes) 213a and 213b with the optical axes of the imaging lenses as centers. It has.

The imaging distance holding member 213 includes an image plane side opposite to the subject with respect to the imaging lens (first imaging lens 211a and second imaging lens 211b) and a solid-state imaging device (first solid-state imaging device). 217a and the second solid-state imaging device 217b) are provided between the formation surfaces of the imaging devices 214a and 214b.
The imaging lens holding member 212 is positioned on the imaging lens (the first imaging lens 211a and the second imaging lens 211b), and together with the imaging distance holding member 213, the imaging lens in the second holding unit 212A on the image plane side. Is sandwiched.
The specific structure of the imaging lens holding member 212 is the same as that of the imaging lens holding member 112 of the first embodiment shown in FIG.
In this embodiment, a silicon carbide (SiC) ceramic material is applied to the imaging lens holding member 212.

Silicon carbide (SiC) -based and silicon nitride (Si ₃ N ₄ ) -based ceramic materials, which are covalent bonding materials having strong bonding forces between atoms, are composed of silicon carbide (SiC) -based ceramic materials at 3 to 4 ppm / ° C. Many ceramic materials of silicon (Si ₃ N ₄ ) having a linear expansion coefficient of 2 to ₃ ppm / ° C. have been commercialized, and solid-state image sensors (first solid-state image sensor 217a and second solid-state image sensor 217b). ) Is suitable as a material for the imaging distance holding member 213.
Ensuring the bonding strength between the imaging element and the imaging distance holding member is facilitated, and thermal fatigue due to the difference in linear expansion coefficient between the members can be reduced.
The dependence of the baseline length on the environmental temperature is reduced, and the dependence of the distance measurement on the environmental temperature can be suppressed. Therefore, the reliability of the distance measuring device is improved.
In addition, the linear expansion coefficient of the silicon wafer which is the main material of the solid-state image sensor (the first solid-state image sensor 217a and the second solid-state image sensor 217b) is about 3 ppm / ° C. and is used for the cover glass of the solid-state image sensor. The material used is AF45 manufactured by shot, and its linear expansion coefficient is 4.5 ppm / ° C.

In addition, silicon carbide-based and silicon nitride-based ceramics are opaque to the visible light range, and the material itself has a light shielding effect, and it is necessary to newly provide a light shielding member for preventing crosstalk. No. Therefore, it is possible to reduce the number of manufacturing steps for forming the light shielding structure and the cost.
The solid-state image sensor (first solid-state image sensor 217a, second solid-state image sensor 217b) protects the image sensor (first image sensor 214a, second image sensor 214b) (prevents scratches, adheres to dust, etc.). For the purpose, a cover glass 215 is provided on the light receiving part side of the image sensor 214 (the first image sensor 214a and the second image sensor 214b).
In addition, the electrodes of the imaging elements 214a and 214b are drawn out by TSV (Through Silicon Via) on the opposite side of the light receiving portion of the imaging elements (the first imaging element 214a and the second imaging element 214b). Solder balls 218a and 218b are disposed on the electrodes.
The electrical board 216 is provided with a circuit including a ranging arithmetic circuit and a digital signal processor (DSP). Solid-state imaging devices 217a and 217b are mounted on the electrodes 219 on the electrical substrate 216 via SMT (Surface Mount Technology) via solder balls 218a and 218b. Furthermore, an underfill agent 220 is formed between the solid-state imaging devices 217a and 217b joined by the solder balls 218a and 218b and the electrical board 216 for the purpose of ensuring the reliability of the joining of the solder balls 218a and 218b.

FIG. 6 is a diagram showing a structure for incorporating an imaging lens (first imaging lens 211a, second imaging lens 211b) into the imaging lens holding member and the imaging distance holding member in the second embodiment. (A) is an image plane side front view of the imaging lens holding member before incorporating the imaging lens, and (A) is a cross sectional view (b), (B) is an image plane side front view of the imaging lens (a). And AA ′ sectional views (b) and (C) are an image plane side front view (a) and an AA ′ sectional view (b) and (B) of the imaging distance holding member 213 before the imaging lens 211 is assembled. 2D is a front view (a) and an AA ′ cross-sectional view (b) of an image plane side of a main part of the camera unit after the imaging lens 211 is incorporated.
As shown in FIG. 6A, the imaging lens holding member 212 and the imaging distance holding member 213 have grooves 212a and 212b along the outer shape of the imaging lens (first imaging lens 211a and second imaging lens 211b). The first imaging lens 211a and the second imaging lens 211b are fitted into the grooves 212a and 212b and assembled.
Key collars 211c are provided at three locations on the collars of the first imaging lens 211a and the second imaging lens 211b, and the imaging lenses (the first imaging lens 211a and the second imaging lens 211b) are grooves. It is designed not to rotate in 212a and 212b.

Besides this shape, the imaging lens (the first imaging lens 211a and the second imaging lens 211b) can be freely designed so as not to rotate.
The groove that matches the outer shape of the imaging lens may be formed on the first holding portion 213A side of the imaging distance holding member 213 or on the second holding portion 212A side of the imaging lens holding member 212. Furthermore, a groove for fitting the imaging lens may be formed in both the imaging lens holding member 212 and the imaging distance holding member 213.

[Third Embodiment]
FIG. 7 is a cross-sectional view showing a configuration of a distance measuring apparatus according to the third embodiment of the present invention.
In the present embodiment, a glass material is used for the imaging lens holding member 312 and the imaging distance holding member 313.
In the solid-state imaging device (the first solid-state imaging device 317a and the second solid-state imaging device 317b), the two imaging devices 314a and 314b are arranged in a line, and the distance between the centers of the imaging devices is the baseline length D (FIG. 1). The structure deserves to be taken.
The two imaging lenses (the first imaging lens 311a and the second imaging lens 311b) have a distance between the centers of the base line length D, and each imaging lens (the first imaging lens 311a and the second imaging lens 311b). Are arranged so as to be substantially orthogonal to and parallel to the respective image sensors (the first image sensor 314a and the second image sensor 314b).
As the imaging lens (first imaging lens 311a, second imaging lens 311b), for example, a glass lens or a resin lens can be used.
An aperture 312 as an imaging lens holding member is provided on the subject side with respect to the imaging lenses (the first imaging lens 311a and the second imaging lens 311b).
The imaging distance holding member forms an image from the imaging lens (the first imaging lens 311a and the second imaging lens 311b) to the solid-state imaging device (the first solid-state imaging device 317a and the second solid-state imaging device 317b). It is a member for holding a distance, and includes openings (through holes) 313a and 313b having respective optical axes of the respective imaging lenses (first imaging lens 311a and second imaging lens 311b) as centers.
In addition, the imaging distance holding member 313 captures the image plane side opposite to the subject and the solid-state imaging devices 317a and 317b with respect to each imaging lens (the first imaging lens 311a and the second imaging lens 311b). It is provided between the formation surfaces of the elements 314a and 314b.

FIG. 8 is a diagram illustrating a structure for incorporating an imaging lens into the imaging distance holding member in the third embodiment. FIG. 8A is an image plane side of the imaging distance holding member before the imaging lens is incorporated. Front view (a) and AA ′ cross-sectional views (b) and (B) are image plane side front views of the imaging lens, and (C) is an image plane of the imaging distance holding member after the imaging lens is incorporated. It is a side front view (a) and AA 'sectional drawing (b).
As shown in FIG. 8A, the first holding portion 313A on the subject side of the imaging distance holding member 313 has a groove along the outer shape of the imaging lens (the first imaging lens 311a and the second imaging lens 311b). 313c and 313d are formed, and the imaging lenses (the first imaging lens 311a and the second imaging lens 311b) are fitted and assembled in the grooves 313c and 313d.
As shown in FIG. 8B, the collars of the imaging lenses 311a and 311b are provided with three key holes 311c, and the imaging lenses 311a and 311b are designed not to rotate within the grooves 313c and 313d. Yes.
In addition to this shape, the imaging lenses 311a and 311b can be freely designed so as not to rotate.
The groove that matches the outer shape of the imaging lens may be formed on the first holding portion 313A side of the imaging distance holding member 313 or on the second holding portion 312A side of the imaging lens holding member 312. Furthermore, a groove for fitting the imaging lens may be formed in both the imaging lens holding member 312 and the imaging distance holding member 313.

The imaging lens holding member (aperture) 312 serving as the second holding unit is provided with the imaging distance holding member 213 and the imaging lenses (the first imaging lens 311a and the second imaging lens 311b) in the second holding unit 312A on the image plane side. ).
As a material for the imaging lens holding member 312 and the imaging distance holding member 313, Tempax glass or Pyrex (registered trademark) glass is suitable.
Tempax glass has a linear expansion coefficient of 3.2 ppm / ° C., and Pyrex (registered trademark) glass has a linear expansion coefficient of 3.7 ppm / ° C., and can be made substantially the same as the linear expansion coefficients of the solid-state imaging devices 317a and 317b.
In this embodiment, Tempax glass is used for the base material 313-1 of the imaging distance holding member 313.

Since the base material 313-1 of the imaging distance holding member 313 has the same linear expansion coefficient in addition to Tempax glass and Pyrex (registered trademark) glass, AF45 and AF32 are also applicable.
The imaging distance holding member 313 made of a base material 313-1 that is transparent in the visible light region, such as glass, requires a light shielding function as means for suppressing crosstalk between the image sensors 314a and 314b.
In the present embodiment, crosstalk is suppressed by adding a light shielding film 313-2 to the base material 313-1 of the imaging distance holding member 313.
The light shielding film 313-2 is formed by forming a chromium or nickel metal film. As a film forming method, a vacuum deposition method, a sputtering method, a plating method, or the like is effective. In particular, the plating method is more practical in securing the adhesion of the film.
Tempax glass made of the same material as the base material 313-1 of the imaging distance holding member 313 was used as the base material 312-1 of the imaging lens holding member (aperture) 312.
As in the case of the imaging distance holding member, AF45 and AF32 can be applied from the linear expansion coefficient in addition to Tempax glass and Pyrex (registered trademark) glass as the base material 312-1 of the imaging lens holding member 312. is there. Further, there is no problem even if the material is different from the base material 313-1 of the imaging distance holding member 313.

Similar to the imaging distance holding member 313, a light shielding film 312-2 is also formed on the base material 312-1 of the imaging lens holding member 312 to provide a light shielding function for suppressing crosstalk.
The light shielding film 312-2 of the imaging lens holding member 312 is formed by depositing a chromium or nickel metal film. As a film forming method, a vacuum deposition method, a sputtering method, a plating method, or the like is effective. In particular, the plating method is more practical in securing the adhesion of the film.
In this embodiment, the light shielding films 312-2 and 313-2 are not formed on the bonding surfaces of the imaging lens holding member 312 and the imaging distance holding member 313, but are bonded on the glass surface. This technique has an advantage that it can be easily joined using a laser welding apparatus.
It has already been found that there is no problem in use even if the light shielding films 312-2 and 313-2 are provided on the bonding surface between the imaging lens holding member 312 and the imaging distance holding member 313 and bonded with an adhesive.
The solid-state imaging device (first solid-state imaging device 317a, second solid-state imaging device 317b) protects the imaging device (first imaging device 314a, second solid-state imaging device 314b) (scratch prevention, dust adhesion, etc.). For this purpose, a cover glass 315 is provided on the light receiving portion side of the image sensor. In addition, a solid-state image sensor (first solid-state image sensor 317a, second solid-state image sensor 317a) is provided with TSV (Through Silicon Via) on the opposite side of the light receiving portion of the image sensor (first image sensor 314a, second solid-state image sensor 314b). The electrode of the solid-state imaging device 317b) is drawn out, and solder balls 318a and 318b are arranged on the drawn-out electrode.
The electrical board 316 is provided with a circuit including a ranging arithmetic circuit and a digital signal processor (DSP). Solid-state image sensors 317a and 317b are mounted on electrodes 319 on the electrical board 316 via SMT (Surface Mount Technology) via solder balls 318a and 318b. Further, for the purpose of securing the reliability of the solder balls 318a and 318b, the solid-state image pickup device (the first solid-state image pickup device 317a and the second solid-state image pickup device 317b) in which the underfill agent 220 is joined by the solder balls 318a and 318b and the electrical equipment Formed between the substrates 316.

Glass (Pyrex (registered trademark) glass, Tempax glass, AF45, AF32) can be made substantially the same as the linear expansion coefficient of the solid-state imaging device (first solid-state imaging device 317a, second solid-state imaging device 317b). It is easy to secure the bonding strength between the element and the imaging distance holding member, and it is possible to reduce thermal fatigue due to a difference in linear expansion coefficient between the members. Therefore, the reliability of the distance measuring device is improved.
Since the linear expansion coefficient of the imaging distance holding member 313 can be made substantially the same as the linear expansion coefficient of the solid-state imaging device (first solid-state imaging device 317a, second solid-state imaging device 317b), the imaging lens (first imaging) It is easy to ensure the bonding strength between the lens 311a, the second imaging lens 311b) and the solid-state imaging device (the first solid-state imaging device 317a, the second solid-state imaging device 317b) and the imaging distance holding member 313. The reliability of the distance measuring apparatus is improved by reducing thermal fatigue due to the difference in linear expansion coefficient between the two.
Since a glass (Pyrex (registered trademark) glass, Tempax glass, AF45, AF32) having a small linear expansion coefficient is applied to the imaging distance holding member that connects the two imaging lenses and the imaging lens holding member, the environment of the baseline length The temperature dependence is reduced, and the environmental temperature dependence of distance measurement can be suppressed.

[Fourth Embodiment]
FIG. 9 is a cross-sectional view showing a configuration of a distance measuring apparatus according to the fourth embodiment of the present invention.
As shown in FIG. 9, in this embodiment, two solid-state image sensors 417a and 417b are mounted on an electrical board 416 that is physically separated.
The two imaging lenses (the first imaging lens 411a and the second imaging lens 411b) have a center-to-center distance, and the optical axes of the imaging lenses 411a and 411b are substantially perpendicular to the imaging elements 414a and 414b. They are arranged in parallel. As the imaging lens (first imaging lens 411a, second imaging lens 411b), for example, a glass lens or a resin lens can be used.
The imaging distance holding member 413 forms an image from the imaging lens (first imaging lens 411a and second imaging lens 411b) to the solid-state imaging device (first solid-state imaging device 417a and second solid-state imaging device 417b). It is a member for maintaining the distance, and includes openings (through holes) 413a and 413b that are formed by the respective optical axes of the imaging lenses 411a and 411b as their centers.
The imaging distance holding member 413 is formed on the imaging lens (first imaging lens 411a, second imaging lens 411b) and solid-state imaging element 417 imaging element (first imaging element 414a, second imaging element 414b) formation surface. It is provided in between. As the imaging distance holding member 413, the same silicon as the main material of the solid-state imaging devices 417a and 417b is used.

The main material of the solid-state imaging device (first solid-state imaging device 417a, second solid-state imaging device 417b) is a ceramic material (silicon carbide (SiC) -based material, silicon nitride (silicon nitride) applied in the second embodiment in addition to silicon. Si ₃ N ₄ ) -based material) and glass materials (Tempax glass, Pyrex (registered trademark) glass, AF45, AF32, etc.) applied in the third embodiment.
The imaging lens holding member 412 is positioned on the imaging lens (the first imaging lens 411a and the second imaging lens 411b), and sandwiches the imaging lenses 411a and 411b together with the imaging distance holding member 413.
The solid-state image sensor (first solid-state image sensor 417a, second solid-state image sensor 417b) protects the image sensor (first image sensor 414a, second image sensor 414b) (scratch prevention, dust adhesion, etc.). For this purpose, a cover glass 415 is provided on the light receiving part side of the image sensor (the first image sensor 414a and the second image sensor 414b). Each image sensor (first image sensor 414a, second image sensor) is provided with TSV (Through Silicon Via) on the opposite side of the light receiving portion of the image sensor (first image sensor 414a, second image sensor 414b). 414b) is drawn out, and solder balls 418a and 418b are arranged on the drawn electrode.

The electrical board 416 is provided with a circuit including a ranging arithmetic circuit and a digital signal processor (DSP). Solid-state imaging devices 417a and 417b are mounted on electrodes 419 on the electrical substrate 416 via SMT (Surface Mount Technology) via solder balls 418a and 418b. Furthermore, an underfill agent 220 is formed between the solid-state imaging devices 417a and 417b joined with the solder balls 418a and 418b and the electrical board 416 for the purpose of securing the reliability of the solder balls 418a and 418b.
Note that the electrical board 416 is at least separated between the extraction electrodes of the imaging elements 414a and 414b.
In this embodiment, an electrical board 416 having a slit (cut) in the middle of the position where the two solid-state imaging devices 417a and 417b are mounted is employed. The electrical board 416 may be divided into two parts.
Since the electrical board 416 is physically separated by the electrode pads 419 corresponding to the two solid-state image pickup devices 417a and 417b, the solder due to the difference in linear expansion coefficient between the solid-state image pickup devices 417a and 417b and the imaging distance holding member 413. The distortion applied to the balls 418a and 418b can be reduced. Therefore, manufacturing yield and reliability are improved.

FIG. 10 is a system configuration diagram using the distance measuring apparatus of the present invention.
The system includes an electrical board 1001, a camera A 1002, a camera B 1003, a processing board 1004, a PC 1005, and an external communication unit 1006.
An electrical board 1001 is a board that draws electrical signals from the camera A 1002 and the camera B 1003.
Cameras A1002 and B1003 are cameras corresponding to the left and right eyes of the stereo camera.

The processing board (parallax calculation means) 1004 receives images taken by the camera A and the camera B and performs calculations for determining the dimensions, mainly image processing.
The PC 1005 can communicate with the processing board 1004 and displays image processing parameter designation, captured images, and images processed on the processing board 1004. A touch panel type dedicated terminal or the like may be prepared instead of the PC.
The external communication unit 1006 communicates with the processing substrate 1004. For example, it is possible to give a shooting trigger to the processing substrate 1004, monitor the operation state of the processing substrate 1004, receive a determination result from the processing substrate 1004, and the like. In general, the external communication unit 1006 is connected to a PLC (Programmable Logic Controller).

  101 Subject, 102a, 102b Camera, 103a, 103b Lens, 104a, 104b Imaging element, 106 Base substrate, 107a, 107b Subject image, 111a, 111b Imaging lens, 111c Keyaki, 112 Imaging lens holding member, 112a Groove, 113 Connection Image distance holding member, 113a Aperture, 114a, 114b Image sensor, 115a, 115b Cover glass, 116 Electrical board, 117a, 117b Solid image sensor, 118a, 118b Solder ball, 119 Image sensor substrate electrode pad, 120 Underfill agent, 211a , 211b imaging lens, 211c keyaki, 212 imaging lens holding member, 212a groove, 213 imaging distance holding member, 214a, 214b imaging element, 215a, 215b cover glass, 216 Substrate, 217a, 217b Solid-state imaging device, 218a, 218b Solder ball, 219 Electrode, 220 Underfill agent, 311a Imaging lens, 311b Imaging lens, 311c Keyaki, 312, Aperture, 312-1 Base material, 312-2 Light shielding film 313 Imaging distance holding member, 313-1, base material, 313-2 light shielding film, 313c groove, 314a, 314b image sensor, 315a, 315b cover glass, 316 electrical board, 317a, 317b solid-state image sensor, 318a, 318b Solder balls, 319 electrodes, 411a, 411b Imaging lens, 412 Imaging lens holding member, 413 Imaging distance holding member, 414a, 414b Imaging element, 415a, 415b Cover glass, 416 Electrical board, 417a, 417b Solid imaging element, 41 a, 418b solder ball 419 electrode, 1001 electrical substrate, 1002 a camera A, 1003 camera B, 1004 substrate, 1005 PC, 1006 external communication unit

JP-A-11-281351

Claims (9)

A plurality of imaging lenses that image light reflected from the subject;
A first holding unit that holds each imaging lens at a portion facing the subject, and a plurality of openings through which light transmitted through the imaging lenses held by the first holding unit passes. 1 holding means;
A plurality of imaging units that are joined to a portion of the first holding unit facing the first holding unit, and that image the light of the subject by imaging the light that has passed through the openings. ,
The first holding means is formed of a material having substantially the same linear expansion coefficient as the main material of the imaging means,
Each of the imaging lenses is held by the first holding portion of the first holding means in a non-adhering manner. The camera unit according to claim 1,
A second holding unit that is bonded to the first holding unit on the side having the first holding unit and fixes each of the imaging lenses with the first holding unit;
The camera unit, wherein the second holding means is formed of a material having substantially the same linear expansion coefficient as the first holding means. The camera unit according to claim 2,
Each imaging lens is held in a groove provided in at least one of the first holding unit of the first holding unit and the second holding unit facing the first holding unit of the second holding unit. A camera unit characterized by The camera unit according to claim 2 or 3,
Each of the imaging lenses is not bonded and fixed to the second holding unit. The camera unit according to any one of claims 2 to 4,
The camera unit, wherein the first holding means and the second holding means are made of silicon. The camera unit according to any one of claims 2 to 4,
The camera unit, wherein the first holding means and the second holding means are made of ceramics of silicon carbide (SiC) or silicon nitride (Si ₃ N ₄ ). The camera unit according to any one of claims 2 to 4,
The camera unit, wherein the first holding means and the second holding means are made of a glass material, and a light shielding film is formed on a surface thereof. The camera unit according to any one of claims 1 to 7,
A camera unit comprising an electrical board on which the plurality of imaging means are surface-mounted, and the electrical board is at least partially divided for each mounting position of the imaging means.   9. A distance measuring apparatus comprising: the camera unit according to claim 8; and parallax calculation means for calculating a distance from the subject based on parallax between a plurality of images captured by the image sensor. .

Images