JP2021033006A - Lens unit and imaging apparatus - Google Patents

Abstract

To provide a lens unit capable of achieving a blooming reduction, prevention of condensation on the lens, and cost reduction.SOLUTION: A lens unit 1 includes: a lens-barrel 10 formed of resin; a first lens 11 held in the lens-barrel 10; a second lens 13; a third lens 14; a fourth lens 15; a fifth lens 16; and an IR cut glass 12 held in the lens-barrel 10 for removing infrared light. The IR cut glass 12 is arranged between the first lens 11 positioned at the forefront of the multiple lenses and the fifth lens 16 positioned at the end of the multiple lenses. An encapsulant 18 is provided between the IR cut glass 12 and the lens-barrel 10.SELECTED DRAWING: Figure 3

Description

The present disclosure relates to a lens unit and an imaging device.

Conventionally, an image pickup apparatus including a lens unit that holds a plurality of lenses and an electronic component unit that incorporates various electronic components including a solid-state image sensor is known. As the solid-state image sensor, for example, a CCD (Charge Coupled Device) type image sensor, a CMOS (Complementary Metal Oxide Semiconductor) type image sensor, or the like is used.

It is known that such an image pickup device removes infrared light before it enters the solid-state image sensor in order to prevent deterioration of image color reproducibility caused by infrared light (Infrared Ray: IR). ing.

As a means for removing infrared light, for example, IR cut glass is known. IR cut glass removes a little less than 100% infrared light. Therefore, a few percent of infrared light passes through the IR cut glass.

The IR cut glass is provided on the lens barrel, which is a component of the lens unit. An electronic component unit is provided on the rear end side of the lens barrel.

For example, when the IR cut glass is installed at the rearmost end of the lens barrel, the IR cut glass exists at a position close to the solid-state image sensor of the electronic component unit. In this case, since there is no lens effect that bends light between the solid-state image sensor and the IR-cut glass, interplane reflection occurs between the solid-state image sensor and the IR-cut glass.

In particular, when the periphery of a strong light source (for example, the sun, headlights, street lights, etc.) is photographed, strong light is incident on the solid-state image sensor. The incident light is reflected by the solid-state image sensor, then reflected by the lens, and returns to the solid-state image sensor. The light returned to the solid-state image sensor in this way causes a phenomenon called blooming in which an image larger than the light source image and having high brightness is generated around the light source image.

For example, in the case of a camera mounted on a vehicle and photographing the rear of the vehicle, the lens unit is always exposed to the headlights of the following vehicle, so that suppression of the occurrence of blooming is an important issue.

Therefore, in order to suppress the occurrence of blooming, for example, it is conceivable to deposit a reflective IR cut coat on a lens installed closer to the subject than the rearmost end of the lens barrel.

However, when the reflective IR cut coat is vapor-deposited on a plastic lens, the linear expansion coefficient of the plastic base material and the linear expansion coefficient of the vapor-deposited material that controls the reflectance are different, so that microcracks occur on the vapor-deposited surface. It will occur. Therefore, the lens on which the reflective IR cut coat is vapor-deposited needs to be limited to a glass lens, but when a glass lens is used, the cost increases as compared with the case where a plastic lens is used.

Further, since the glass lens has a curvature, depending on the surface shape of the reflective IR cut coat, the reflected light becomes reflected light that is conversely focused, so that strong ghost light is generated in the solid-state image sensor. There is. Therefore, it is not preferable to deposit a reflective IR cut coat on the glass lens in the lens unit.

From the above, it is important to install IR cut glass at the rearmost end of the lens barrel and prevent blooming as much as possible.

Therefore, it is conceivable to use an absorption type IR cut glass which uses a glass capable of absorbing infrared light. This absorption type IR cut glass can suppress the occurrence of blooming as compared with the reflection type IR cut glass.

However, the absorption type IR cut glass is much more expensive than the reflective IR cut glass, and the cost increases.

Therefore, in order to reduce the cost increase in the entire lens unit when the absorption type IR cut glass is provided at the rearmost end of the lens barrel, it is conceivable to change the member of the lens barrel from an expensive metal to an inexpensive resin. Hereinafter, the lens barrel made of resin is referred to as a "resin lens barrel".

As described above, an electronic component unit containing various electronic components including a solid-state image sensor is provided on the rear end side of the lens barrel. The power consumption of electronic components is increasing with the recent increase in image quality and frame rate. Therefore, the amount of heat generated by electronic components tends to increase. As a result, the inside of the electronic component unit becomes a high temperature state.

Further, in a high humidity environment (for example, in rainy weather), the inside of the electronic component unit becomes in a high humidity state due to the inflow of high humidity outside air. The high-humidity outside air flows into the electronic component unit from, for example, a component (for example, a connector connected to an external device) made of a moisture-permeable material (for example, resin) provided in the electronic component unit.

Therefore, high temperature and high humidity air may be present in the electronic component unit.

Since the resin lens barrel is made of a moisture-permeable resin, this high-temperature and high-humidity air flows into the lens unit from the electronic component unit via the resin lens barrel. Even if the contact portion between the absorbent IR cut glass provided at the rearmost end of the resin lens barrel and the resin lens barrel is sealed with an adhesive or the like, it is difficult to prevent the inflow of air.

At this time, since the resin lens barrel is not provided with an electronic component that generates heat, the temperature inside the resin lens barrel is lower than the temperature inside the electronic component unit. For example, when the resin lens barrel is exposed to the outside air, the temperature inside the resin lens barrel becomes the same as the outside air temperature. Therefore, since the temperature difference between the inside of the electronic component unit and the inside of the lens unit is large, when the high temperature and high humidity air flowing into the lens unit is cooled, dew condensation occurs on the surface of the lens on the most subject side. The lens surface becomes cloudy.

Japanese Patent No. 4234626 Japanese Patent No. 4999506

As a means for preventing this dew condensation, for example, Patent Documents 1 and 2 disclose a lens unit provided with an antifogging member between the lens closest to the subject and the lens adjacent thereto.

However, there is a problem that a new cost is required to install the anti-fog member.

An object of one aspect of the present disclosure is to provide a lens unit and an image pickup apparatus that realizes reduction of blooming, prevention of dew condensation on a lens, and reduction of cost.

The lens unit according to one aspect of the present disclosure includes a lens barrel made of resin, a plurality of lenses held in the lens barrel, and an IR (Infrared Ray) held in the lens barrel to remove infrared light. ) Cut glass, and the IR cut glass is between the state-of-the-art lens arranged at the most advanced end among the plurality of lenses and the end end lens arranged at the end end of the plurality of lenses. A sealant is provided between the IR cut glass and the lens barrel.

The imaging device according to one aspect of the present disclosure includes a lens unit according to one aspect of the present disclosure and an electronic component unit provided on the rear end side of the lens unit and provided with a plurality of electronic components.

According to the present disclosure, it is possible to reduce blooming, prevent dew condensation on the lens, and reduce the cost.

A perspective view showing the appearance of the image pickup apparatus according to the first to third embodiments of the present disclosure. Side sectional view of the image pickup apparatus according to the first to third embodiments of the present disclosure. Side sectional view of the lens unit according to the first embodiment of the present disclosure. Side sectional view of the lens unit according to the second embodiment of the present disclosure. Side sectional view of the lens unit according to the third embodiment of the present disclosure.

Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. The components common to each figure are designated by the same reference numerals, and the description thereof will be omitted as appropriate.

(Embodiment 1)
The configuration of the image pickup apparatus 100 according to the first embodiment of the present disclosure will be described with reference to FIGS. 1 to 3.

FIG. 1 is a perspective view showing the appearance of the image pickup apparatus 100. FIG. 2 is a side sectional view of the image pickup apparatus 100. FIG. 3 is a side sectional view of the lens unit 1.

The image pickup device 100 is, for example, a camera mounted on a vehicle and taking a picture of the periphery of the vehicle.

As shown in FIGS. 1 and 2, the image pickup apparatus 100 includes a lens unit 1 and an electronic component unit 2.

The electronic component unit 2 is provided on the rear end side of the lens unit 1. For example, the lens tip portion of the lens unit 1 is provided so as to be exposed from the vehicle body, and the electronic component unit 2 is provided inside the vehicle body.

As shown in FIG. 2, the electronic component unit 2 has a solid-state image sensor 21, a solid-state image sensor substrate 22, an image processing circuit 23, a power supply circuit 24, a communication circuit 25, a power supply board 26, and a connector inside the housing 20. It has 27. These electronic components are electrically connected to each other. Note that in FIG. 2, the components (see FIG. 3) in the lens unit 1 are not shown.

The solid-state image sensor 21 is mounted on the solid-state image sensor substrate 22, and converts the light from the lens unit 1 into an electric signal. As the solid-state image sensor 21, for example, a CCD type image sensor or a CMOS type image sensor can be used.

The image processing circuit 23 is mounted on the solid-state image sensor substrate 22, and performs various processing on the electric signal from the solid-state image sensor 21 to generate a video signal. Then, the image processing circuit 23 transmits the video signal to the communication circuit 25 mounted on the power supply board 26.

The communication circuit 25 transmits the video signal from the image processing circuit 23 from the connector 27 to an external device (not shown) by a predetermined communication method.

The power supply circuit 24 is mounted on the power supply board 26, and uses electric power obtained from outside the image pickup apparatus 100 to supply power to each of the solid-state image pickup element 21, the image processing circuit 23, and the communication circuit 25. As a result, the solid-state image sensor 21, the image processing circuit 23, and the communication circuit 25 can each perform the above-described operations. Further, the solid-state image sensor 21, the image processing circuit 23, the power supply circuit 24, and the communication circuit 25 each generate heat when energized.

As shown in FIG. 3, the lens unit 1 has a first lens 11, an IR cut glass 12, a second lens 13, a third lens 14, a fourth lens 15, and a fifth lens 16 in a lens barrel 10.

The first lens 11 is a lens (in other words, a lens located closest to the subject) arranged at the most advanced position among the five lenses. The first lens is located at the position farthest from the solid-state image sensor 21 among the five lenses. The first lens 11 corresponds to an example of a “state-of-the-art lens”.

The second lens 13 is a lens arranged second from the first lens. The second lens 13 corresponds to an example of the “second lens”. The third lens 14 is a lens arranged third from the first lens. The fourth lens 15 is a lens arranged fourth from the first lens.

The fifth lens 16 is a lens arranged at the rearmost end of the five lenses. The fifth lens 16 is located closest to the solid-state image sensor 21 among the five lenses. The fifth lens 16 corresponds to an example of the "rearmost lens".

The lens barrel 10 is, for example, a member having a substantially cylindrical shape. The lens barrel 10 holds the first lens 11, the IR cut glass 12, the second lens 13, the third lens 14, the fourth lens 15, and the fifth lens 16 on the inner peripheral surface thereof. The lens barrel 10 is a resin lens barrel made of a moisture-permeable resin. Further, the lens barrel 10 is provided with an adhesive portion 10a that is adhered to the electronic component unit 2.

A sealing material 17 is provided between the first lens 11 and the lens barrel 10. The sealing material 17 is, for example, an O-ring.

The IR cut glass 12 has a function of removing infrared light. As the IR cut glass 12, either a reflective IR cut glass or an absorption type IR cut glass can be used. Alternatively, glass in which a reflective IR cut coat is added to the absorbent IR cut glass may be used.

A sealing agent 18 is provided between the IR cut glass 12 and the first lens 11, and between the IR cut glass 12, the second lens 13, and the lens barrel 10. As the sealing agent 18, for example, a resin such as an adhesive, more preferably an ultraviolet curable resin or the like is used. Since the sealing structure (which may be called a heat insulating structure) is formed by the sealing agent 18 and the IR cut glass 12, the fluid from the second lens 13 side to the first lens 11 side (for example, high temperature and high humidity). The inflow of air) can be blocked.

The configuration of the image pickup apparatus 100 according to the first embodiment has been described above.

(Embodiment 2)
In the first embodiment, the case where the sealing agent 18 is provided between the IR cut glass 12 and each of the first lens 11 and the second lens 13 in the lens unit 1 has been described as an example, but the present invention is limited to this. Not done.

For example, as shown in FIG. 4, the sealing agent 18 may be provided between the IR cut glass 12 and the lens barrel 10. As a result, a sealing structure made of the sealing agent 18 and the IR cut glass 12 is formed, so that the inflow of fluid (for example, high temperature and high humidity air) from the second lens 13 side to the first lens 11 side is blocked. can do.

(Embodiment 3)
In the first and second embodiments, the case where the IR cut glass 12 is provided between the first lens 11 and the second lens 13 in the lens unit 1 has been described as an example, but the present invention is not limited to this.

For example, as shown in FIG. 5, the IR cut glass 12 may be provided between the third lens 14 and the fourth lens 15.

Further, in this case, the sealing agent 18 may be provided between the IR cut glass 12 and the lens barrel 10. As a result, a sealing structure made of the sealing agent 18 and the IR cut glass 12 is formed, so that the inflow of fluid (for example, high-temperature and high-humidity air) from the fourth lens 15 side to the third lens 14 side is blocked. can do.

According to the first to third embodiments described above, the following effects are obtained.

The image pickup apparatus 100 of the present embodiment is characterized in that a resin lens barrel made of resin is used as the lens barrel 10. Therefore, even when a relatively expensive absorption type IR cut glass is used as the IR cut glass 12, it is possible to reduce the cost increase in the entire lens unit 1.

Further, the image pickup apparatus 100 of the present embodiment is characterized by having a sealing structure with an IR cut glass 12 and a sealing agent 18. As a result, it is possible to prevent the high temperature and high humidity air from the electronic component unit 2 from flowing into the first lens 11. Therefore, dew condensation on the first lens 11 can be prevented. As a result, fogging of the first lens 11 can be prevented.

Further, the image pickup apparatus 100 of the present embodiment is characterized in that the IR cut glass 12 is provided. As a result, among the light rays incident from the first lens 11, the infrared rays incident on the solid-state image sensor 21 can be significantly attenuated. As a result, deterioration of the color reproducibility of the image can be prevented.

Further, the image pickup apparatus 100 of the present embodiment is characterized in that the IR cut glass 12 is provided closer to the subject than the rearmost end of the lens barrel 10. As a result, the IR cut glass 12 can be kept away from the solid-state image sensor 21, and blooming can be reduced.

For example, regardless of whether the absorption type IR cut glass or the reflection type IR cut glass is used as the IR cut glass 12, the light reflected on the surface of the solid-state image sensor 21 returns to the absorption type IR cut glass and is on the surface. Reflects at. This reflected light is diffused on the solid-state image sensor 21 by passing through each lens in the lens barrel 10. As a result, the irradiation amount per unit area of the solid-state image sensor 21 can be reduced as compared with the case where the IR cut glass 12 is provided at the rearmost end of the lens barrel 10. Therefore, in the image pickup apparatus 100 according to the present disclosure, blooming caused by inter-plane reflection between the surface of the solid-state image sensor and the IR cut glass 12 can be reduced.

Further, the image pickup apparatus 100 of the present embodiment is characterized in that the IR cut glass 12 is provided closer to the subject than the rearmost end of the lens barrel 10. Therefore, the length of the lens barrel 10 can be shortened.

The present disclosure is not limited to the description of the above embodiment, and various modifications can be made without departing from the spirit of the present embodiment.

The lens unit and imaging device of the present disclosure are useful for a camera mounted on a vehicle.

1 Lens unit 2 Electronic component unit 10 Lens tube 10a Adhesive part 11 1st lens 12 IR cut glass 13 2nd lens 14 3rd lens 15 4th lens 16 5th lens 17 Encapsulant 18 Encapsulant 20 Housing 21 Solid Image sensor 22 Solid-state image sensor board 23 Image processing circuit 24 Power supply circuit 25 Communication circuit 26 Power supply board 27 Connector 100 Image pickup device

Claims (8)

A lens barrel made of resin and
A plurality of lenses held in the lens barrel and
It has an IR (Infrared Ray) cut glass that is held in the lens barrel and removes infrared light.
The IR cut glass is
It is arranged between the state-of-the-art lens arranged at the most advanced end among the plurality of lenses and the end end lens arranged at the end end of the plurality of lenses.
A sealant is provided between the IR cut glass and the lens barrel.
Lens unit. The IR cut glass is
It is arranged between the state-of-the-art lens and the second lens arranged second from the state-of-the-art lens.
The lens unit according to claim 1. A sealant is provided between the IR cut glass and each of the state-of-the-art lens and the second lens.
The lens unit according to claim 2. The IR cut glass is
Either absorbent IR cut glass or reflective IR cut glass,
The lens unit according to any one of claims 1 to 3. The sealant is an ultraviolet curable resin.
The lens unit according to any one of claims 1 to 4. The lens unit according to any one of claims 1 to 5.
An electronic component unit provided on the rear end side of the lens unit and provided with a plurality of electronic components.
Imaging device. The plurality of electronic components
A solid-state image sensor that converts light from the lens unit into an electrical signal,
An image processing circuit that generates a video signal based on an electrical signal from the solid-state image sensor,
A communication circuit that transmits a video signal from the image processing circuit to an external device,
A solid-state image sensor, an image processing circuit, and a power supply circuit that supplies power to the communication circuit.
The imaging device according to claim 6. Mounted on the vehicle,
Used for photographing the surroundings of the vehicle,
The imaging device according to claim 6 or 7.

Images