CN214256407U - Camera module - Google Patents

Abstract

The utility model discloses realize small-size and prevent the high camera module of dewfall performance under the low temperature environment. A camera module (10) of the present disclosure includes: an imaging window (1), an imaging element (2), a heater (3), and a housing (4) that contains the imaging window (1), the imaging element (2), and the heater (3), wherein the heater (3) has: a ceramic base (31); a heating resistor (32) provided on the ceramic base (31); and a heat radiation film (33) on the surface of the ceramic base (31).

Description

Camera module

Technical Field

The present disclosure relates to a camera module of a monitoring camera or an in-vehicle camera or the like for crime prevention.

Background

As a camera module, for example, as shown in patent document 1, an imaging device including an imaging window, a lens, and an imaging element is known. The imaging device disclosed in patent document 1 further includes a heater and a fan, and patent document 1 discloses that condensation in a low-temperature environment is prevented by feeding hot air to the imaging window. In recent years, there is a demand for a compact and lightweight imaging device.

Prior art documents

Patent document

Patent document 1: japanese patent laid-open publication No. 2018-14700

However, since such an imaging device includes a fan for supplying hot air to the imaging window, it is difficult to reduce the size of the device. In addition, when a small fan is used, the output of the air flow decreases, and it is therefore difficult to prevent condensation in a low-temperature environment.

SUMMERY OF THE UTILITY MODEL

Problem to be solved by utility model

An object of the present disclosure is to provide a camera module that is small in size and has high dew condensation prevention performance in a low-temperature environment.

Means for solving technical problems

The disclosed camera module is provided with: the image pickup device includes an image pickup window, an image pickup element, a heater, and a case including the image pickup window, the image pickup element, and the heater, wherein the heater includes a ceramic base, a heating resistor provided on the ceramic base, and a heat radiation film provided on a surface of the ceramic base.

-utility model effect-

According to the camera module of the present disclosure, the heater has a heat radiation film on a surface of the ceramic base. This can increase the intensity of radiant heat radiated from the heater surface. Therefore, the dew condensation prevention performance in a low-temperature environment can be improved without using a fan. As a result, the camera module can be downsized, and the dew condensation prevention performance in a low temperature environment can be improved.

Drawings

Fig. 1 is a schematic diagram showing an example of a camera module of the present disclosure.

Fig. 2 is a schematic diagram representing another example of the camera module of the present disclosure.

Fig. 3 is a schematic diagram representing another example of the camera module of the present disclosure.

Fig. 4 is a schematic diagram representing another example of the camera module of the present disclosure.

Fig. 5 is a schematic diagram representing another example of the camera module of the present disclosure.

Fig. 6 is a schematic diagram illustrating an example of a heater used in the camera module of the present disclosure.

Fig. 7 is a schematic diagram representing another example of the camera module of the present disclosure.

Fig. 8 is a schematic diagram representing another example of the camera module of the present disclosure.

Fig. 9 is a schematic diagram representing another example of the camera module of the present disclosure.

Fig. 10 is a schematic view showing an example of a positional relationship between a heat conductive member and a heater in the camera module of the present disclosure.

Fig. 11 is a schematic view showing another example of the positional relationship of the heat conductive member and the heater in the camera module of the present disclosure.

Fig. 12 is a schematic diagram representing another example of the camera module of the present disclosure.

Fig. 13 is a schematic diagram representing another example of the camera module of the present disclosure.

Fig. 14 is a schematic diagram representing another example of the camera module of the present disclosure.

-description of symbols-

1: the photographing window 2: the imaging element 3: heater 31: ceramic matrix 32: the heating resistor 33: heat radiation film 4: a housing 5: a lens 6: the camera body portion 7: the reflection plate 8: electrode extraction unit 9: heat conductive member 10: a camera module.

Detailed Description

The camera module 10 will be described in detail.

Fig. 1 is a schematic diagram showing an example of a camera module 10. As shown in fig. 1, the camera module 10 includes an imaging window 1, an imaging element 2, a heater 3, and a housing 4.

The camera module 10 may be used for a surveillance camera installed in a house for crime prevention, for example, or may be mounted in a mobile communication device such as an automobile or an unmanned aerial vehicle.

The camera module 10 is covered by the housing 4, and can photograph a subject through the photographing window 1 which is a part of the housing 4. The camera module 10 may further have a lens 5 and a camera body portion 6. The camera module 10 may also have further components for image processing or digital data storage. The camera body 6 may acquire the temperature inside the camera module 10 by a connected temperature sensor, and compare the internal temperature with a predetermined threshold value to control the operation of the heater 3.

The camera module 10 can form an object image on the image pickup device 2 through an image pickup optical system such as the lens 5. The camera module 10 can capture a subject image using the image pickup device 2 to generate an image signal. Further, the camera module 10 can output an image signal to the display device via the signal connection portion. The display device can display a subject image corresponding to the image signal acquired from the signal connection unit.

When the camera module 10 is placed in a low-temperature environment, the camera body 6 is heated because the circuit generates heat by energization, but the periphery of the imaging window 1 is easily cooled by outside air. Therefore, there is a fear that dew condensation of the imaging window 1 occurs or fine moisture such as mist is generated in the module. The camera module 10 has the heater 3, and thus can remove moisture. The heater 3 may simply perform ON/OFF control, or may control the amount of heat generation. The heater 3 may be formed by arranging a plurality of resistor bodies, for example, and controlling the amount of heat generation by variably controlling the current or voltage flowing through the resistor bodies.

The imaging window 1 in the camera module 10 of the present disclosure is a light-transmitting member, and is a member through which light from an object passes. Here, the imaging window 1 may be, for example, a lens cover that protects the lens 5 or the lens 5. The camera window 1 may also form part of the housing 4. Here, the imaging window 1 includes a member such as glass, acrylic, plastic, or polycarbonate. The imaging window 1 is a member heated by radiation from a heat radiation film 33 described later. The imaging window 1 may have metal particles or the like inside in order to be efficiently heated by radiation from a heat radiation film 33 described later.

As shown in fig. 1 and 6, the heater 3 in the camera module 10 of the present disclosure includes a ceramic substrate 31, a heating resistor 32 provided on the ceramic substrate 31, and a heat radiation film 33 positioned on the surface of the ceramic substrate 31.

The ceramic base 31 is a member for protecting the heating resistor 32. The ceramic substrate 31 is made of, for example, a ceramic material such as alumina, cordierite, mullite, aluminum titanate, β -spodumene, zircon or titania. The shape of the ceramic substrate 31 may be, for example, a round bar shape, a plate shape, or a cylindrical shape. The ceramic base 31 can be reduced in size to be accommodated in the case 4. For example, the ceramic substrate 31 may have a plate shape with a length of 10 to 160mm, a thickness of 0.5 to 5.5mm, and a width of 5 to 160 mm.

The heating resistor 32 is a member that generates heat by energization. The heating resistor 32 may be made of gold, silver, tungsten, molybdenum, silver palladium, or the like. The heating resistor 32 is provided inside or on the surface of the ceramic body. The heat generating resistor 32 may be a meandering pattern having a plurality of folded portions.

The heater 3 can transfer heat generated by the heating resistor 32 to the imaging window 1 by radiation. The heater 3 may be conducted through the housing 4 by heat conduction to heat the imaging window 1.

The heat radiation film 33 is a member for enhancing the radiation of the heater 3. The heat radiation film 33 is provided on the surface of the ceramic substrate 31. The heat radiation film 33 may be a ceramic containing at least one of metals such as Mo, W, Ni, Cr, Fe, Co, Mn, and Ti as a blackening component. Also, the heat radiation film 33 may have the same material as the ceramic substrate 31 as a main component. This can reduce the thermal stress generated between the ceramic substrate 31 and the heat radiation film 33. The heat radiation film 33 is ceramic containing a blackening component, and thus radiation efficiency can be improved. In particular, the heat radiation film 33 may also be a ceramic coating including molybdenum or tungsten. In this case, the efficiency of radiation can be further improved.

The heat radiation film 33 may be provided on the surface of the ceramic substrate 31 to increase the heat emissivity. For example, when the conditions such as the shape and the size of the heat radiation film 33 are made close to those of the ceramic substrate 31, the emissivity in the infrared region may be higher than that of the ceramic substrate 31. The heat radiation film 33 is, for example, a black or gray member. Further, the heat radiation film 33 may have a surface rougher than the ceramic substrate 31, for example. This can improve the emissivity.

The heater 3 has a heat radiation film 33, and the heating resistor 32 is heated by energization, whereby electromagnetic waves in the infrared region are radiated in a wide range from the heat radiation film 33. The mist or condensed water inside and outside the housing 4 can be heated and evaporated by the radiant heat in the infrared region. Further, the surrounding glass or plastic is also heated at the same time, and the amount of moisture existing on the optical axis inside the housing 4 can be reduced.

Further, as the temperature becomes lower, the saturated water vapor pressure decreases, so the outside air temperature decreases, and when the temperature inside the apparatus is 0 ℃ or lower, almost all the water vapor in the air condenses, and appears as frost (freeze). At this time, when the heater 3 is operated, the air around the heater 3 is heated to raise the temperature to 0 ℃ or higher and the saturated water vapor pressure is raised, so that frost in the vicinity of the heater 3 can be eliminated.

When the heated air containing water vapor floats in the imaging window 1, the surface of the imaging window 1 is cooled, and the saturated water vapor pressure decreases. When the temperature near the imaging window 1 is 0 ℃ or lower and the water vapor pressure is higher than the saturated water vapor pressure at that temperature, frost condenses on the surface of the imaging window 1.

By providing the heat radiation film 33 on the surface of the ceramic substrate 31, the radiation intensity in the near-to mid-infrared region among the infrared region radiation heat can be increased. Therefore, the effect of removing floating fine moisture can be improved.

Further, since the heater 3 has the heat radiation film 33, the intensity of the radiation heat radiated from the surface of the heater 3 can be increased. Therefore, the dew condensation prevention performance in a low-temperature environment can be improved without using a fan. As a result, the camera module 10 can be downsized, and the dew condensation prevention performance in a low temperature environment can be improved.

As shown in fig. 3, the shape of the case 4 may be a shape having a trapezoidal cross section obtained by cutting a part of a rectangular parallelepiped. Thus, by arranging the imaging window 1 obliquely, it becomes difficult to attach the imaging window 1 during snowfall, and it is possible to melt snow on the upper portion of the casing 4. In addition, water droplets are hard to flow on the surface of the imaging window 1 during rainfall. The infrared camera, which is susceptible to moisture, can have particularly excellent functions. Further, as shown in fig. 4, the case 4 may have a hemispherical portion. By forming the hemispherical portion of the housing 4 as the imaging window 1, the possibility of snow adhering to the imaging window 1 during snowfall can be reduced.

At the same time, the dew condensation of the case 4 can be prevented, the optical axis fog of the lens 5 can be eliminated by the radiant heat, and the water vapor can be eliminated by the heater 3 by effectively utilizing the characteristic that the water vapor easily rises. In particular, when the straight-traveling characteristic by infrared light is excellent, even if the optical axis of the lens 5 and the imaging window 1 do not travel straight, the infrared light can travel straight without being refracted by the imaging window 1, and thus the infrared camera can have an excellent function. At the same time, the radiation heat from the heater 3 does not reflect on the imaging window 1 and reaches the lens 5, and therefore, halation is less likely to occur. By heating the imaging window 1 itself, the possibility of freezing outside the imaging window 1 can be reduced. Further, since the intensity of the heat radiation in the direction perpendicular to the surface of the heater 3 is the strongest, by disposing the imaging window 1 in the irradiation direction of the surface of the heat radiation film 33, condensation on the imaging window 1 can be further prevented.

The heater 3 may be located at a position deviated from the optical axis of the camera lens 5. This is because the intensity of the heat radiation in the direction perpendicular to the surface of the heater 3 is the strongest, and therefore, by shifting the optical axis of the lens 5 from the optical axis of the infrared radiation of the heater 3, the halo at the time of photographing can be reduced.

Further, as shown in fig. 3, the heater 3 may be provided on the inner peripheral surface of the housing 4. Thus, heat generated by the heater 3 can be transmitted to the imaging window 1 via the housing 4 by heat conduction. This enables the imaging window 1 to be heated by both heat conduction and heat radiation.

As shown in fig. 6, the heater 3 may further include an electrode lead-out portion 8, and the electrode lead-out portion 8 may be located on a surface of the ceramic substrate 31 opposite to the surface on which the heat radiation film 33 is provided. This can reduce the possibility that the electrode lead-out portion 8 is heated by the influence of radiant heat. As a result, heating of the circuit portion connected to the heater 3 can be suppressed, and long-term reliability of the circuit can be improved.

As shown in fig. 6, the heater 3 may have a plate shape, and the heating resistor 32 may be positioned so as to be sandwiched between a plurality of sheet-shaped ceramic substrates 31. In this case, the heat radiation film 33 may be provided on the entire surface of the ceramic substrate 31 or may be provided only on one main surface facing the inside of the case 4. Compared to the case where the heat radiation film 33 is provided on the entire surface of the ceramic substrate 31, the intensity of radiation can be partially increased, and the heat capacity of the entire heater 3 can be reduced, so that the temperature increase rate of the imaging window 1 can be further increased.

As shown in fig. 2, the heater 3 is cylindrical, and the imaging window 1 may be located inside the heater 3. This enables the imaging window 1 to be uniformly heated in the circumferential direction. At this time, the outer peripheral surface of the heater 3 may be in contact with the case 4.

As shown in fig. 5, a reflection plate 7 for reflecting radiant heat may be further provided. The reflecting plate 7 thereby reflects radiant heat, thereby heating the imaging window 1. The reflection plate 7 may be a metal member such as aluminum, copper, or stainless steel. The reflection plate 7 may be located on the inner circumferential surface of the housing 4, for example. The reflecting plate 7 may be located so as to cover the heater 3. This enables the radiant heat from the heater 3 to be reflected in a wide range.

As shown in fig. 7 and 8, the heater 3 may be in contact with the imaging window 1. This allows heat emitted from the heater 3 to be transferred to the imaging window 1 by heat transfer. Therefore, the imaging window 1 can be heated more efficiently. This can further reduce the possibility of dew condensation on the imaging window 1.

In this case, as shown in fig. 7, the heater 3 is a plate-like member, and the main surface may be in contact with the imaging window 1. In this case, since heat transfer between the surfaces occurs, the imaging window 1 can be heated more efficiently. As shown in fig. 8, the end of the heater 3 may be in contact with the imaging window 1. In this case, when viewed from the optical axis direction (direction perpendicular to the lens 5), the overlap of the photographing window 1 and the heater 3 can be reduced. Therefore, the field of view of the camera module 10 can be enlarged.

As shown in fig. 9, a heat conduction member 9 may be further provided to be in contact with the heater 3 and the imaging window 1, respectively. This enables heat emitted from the heater 3 to be transmitted to the imaging window 1 via the heat conductive member 9. Therefore, the imaging window 1 can be heated more efficiently. This can further reduce the possibility of dew condensation on the imaging window 1. Here, the heat conduction member 9 may be a member having a thermal conductivity higher than that of ceramic. The heat conductive member 9 is a metal member such as stainless steel, aluminum, silver, or copper, for example. The heater 3 and the heat conductive member 9 may be bonded by a bonding material made of, for example, resin. The heater 3 and the heat conductive member 9 may be bonded to each other via grease or the like, for example.

Further, as shown in fig. 7 and 8, when the heater 3 is in contact with the imaging window 1, or when a heat conduction member 9 is further provided in contact with the heater 3 and the imaging window 1 as shown in fig. 9, the imaging window 1 can be heated more efficiently than when the imaging window 1 is heated by radiation from the heater 3. Therefore, not only dew condensation is prevented, but also frost or ice adhering to the surface of the imaging window 1 can be induced even in an environment where the outside of the camera freezes. As a result, the subject can be clearly imaged even in a severe external environment such as below the freezing point.

Further, as shown in fig. 10, the heat conductive member 9 is provided so as to surround the photographing window 1. In this case, heat can be uniformly transferred to the imaging window 1 in the circumferential direction. Therefore, dew condensation or freezing occurring in the imaging window 1 can be uniformly eliminated in the circumferential direction.

As shown in fig. 10, the heat conduction member 9 may be a hollow plate-like (disk-like) member, and a plurality of heaters 3 may be provided on the surface thereof. This manages the heat transfer to the imaging window 1 uniformly in the circumferential direction. Further, by arranging the plurality of heaters 3 uniformly in the circumferential direction, stress caused by a difference in thermal expansion between the heaters 3 and the heat conductive member 9 can be reduced. As a result, the long-term reliability of the camera module 10 can be improved.

As shown in fig. 11, the heat conduction member 9 may be an annular member having a plurality of heaters 3 on the inner peripheral surface. At this time, the inner peripheral surface of the heat conduction member 9 may have a linear portion when viewed from the optical axis direction, and the heater 3 may be provided at the linear portion. This can increase the contact area between the heater 3 and the heat conduction member 9, and therefore, the heat generated from the heater 3 can be transmitted to the imaging window 1 via the heat conduction member 9. Therefore, the imaging window 1 can be heated more efficiently. This can further reduce the possibility of dew condensation on the imaging window 1.

As shown in fig. 13, the heat radiation film 33 may be provided on the surface of the heater 3 that contacts the heat conductive member 9. Thereby, the heat of the heater 3 can be transferred to the imaging window 1 via the heat conduction member 9, and the imaging window 1 can be further heated by the radiation from the heat radiation film 33. Therefore, the imaging window 1 can be heated more efficiently. This can further reduce the possibility of dew condensation on the imaging window 1.

As shown in fig. 14, the heat radiation film 33 may be provided on the opposite surface of the heater 3 from the surface in contact with the heat conductive member 9. Thereby, not only the imaging window 1 is heated by heat conduction and heat radiation, but also the lens 5, the imaging element 2, or the drive circuit inside the housing 4 can be heated by the heat radiation effectively. Therefore, for example, the auxiliary heating can be performed before operating the camera. As a result, even immediately after the camera module 10 is operated, imaging can be performed at a response speed as in the case of room temperature.

Hereinafter, a method for manufacturing the ceramic substrate 31 and the heat radiation film 33 containing alumina will be described. In alumina (Al)₂O₃) The original ceramic sheet of (1) is patterned by applying a conductive paste containing W, Mo or the like on one main surface thereof by a printing method, and applying another paste containing 0.3 to 12 wt% of MgO, CaO and SiO on the other main surface thereof₂、ZrO₂At least 1 kind of (A) and 0.3-10 wt%The oxide is added as the blackening component, and the balance is Al₂O₃The original ceramic sheet and a ceramic sheet containing a raw ceramic in an unfired state are laminated with the other principal surface facing outward. The green ceramic for ceramic sheet also contains 0.3-12 wt% of MgO, CaO and SiO₂And at least 1 or more kinds of alumina selected from ZrO 3. And then, sintering at 1400-1700 ℃ in a reducing atmosphere environment. Thus, the heater 3 is obtained in which the black heat radiation film 33 is coated on the outer peripheral surface of the plate-like ceramic body 31 in which the pattern 5 of the heating resistor 32 is embedded, in a state of being integrally sintered.

According to the above production method, even if oxides of Mo, W, Ni, Cr, Fe, Co, Mn, and Ti are added, the oxides or metal monomers are insufficiently reduced by firing in a reducing atmosphere environment, and these become blackened components.

As described above, according to the heater 3 of the present disclosure, the black heat radiation film 33 is coated on the white ceramic substrate 31, thereby improving the heat radiation property in the infrared region.

In addition, as in the present disclosure, when the blackened heat radiation film 33 is formed on the white ceramic substrate 31, the blackened heater 3 is prevented from being blackened because the white ceramic substrate 31 can be transmitted if the heat radiation film 33 is made significantly thin. Therefore, by increasing the thickness of the heat radiation film 33 to 10 μm or more, preferably 15 μm or more, the color tone of the heater 3 does not become pale due to the white color of the ceramic substrate 31, and as a result, more excellent heat radiation rate can be obtained.

Claims (13)

1. A camera module is characterized by comprising:

a photographing window;

an imaging element;

a heater; and

a housing including the imaging window, the imaging element, and the heater,

the heater has: a ceramic substrate; a heating resistor provided on the ceramic base; and a heat radiation film on a surface of the ceramic base.

2. The camera module of claim 1,

the imaging window is located in a direction perpendicular to a surface of the ceramic base on which the heat radiation film is provided.

3. The camera module according to claim 1 or 2,

the heater is disposed on an inner circumferential surface of the housing.

4. The camera module according to claim 1 or 2,

the heater further has an electrode take-out portion,

the electrode extraction portion is located on a surface of the ceramic base opposite to a surface on which the heat radiation film is provided.

5. The camera module according to claim 1 or 2,

the heater is in the form of a plate,

the heating resistor is provided along the heat radiation film.

6. The camera module according to claim 1 or 2,

the heater is in the shape of a cylinder,

the photographing window is located inside the heater.

7. The camera module according to claim 1 or 2,

the camera module further has: a reflection plate for reflecting radiant heat.

8. The camera module according to claim 1 or 2,

the heater is connected with the photographing window.

9. The camera module according to claim 1 or 2,

the camera module further has: and a heat conduction member connected to the heater and the imaging window, respectively.

10. The camera module of claim 9,

the heat conductive member is disposed to surround the photographing window.

11. The camera module of claim 10,

the heat conduction member is a hollow plate-like member, and a plurality of the heaters are provided on a surface thereof.

12. The camera module of claim 11,

the heat conduction member is an annular member and has a plurality of heaters provided on an inner peripheral surface thereof.

13. The camera module of claim 9,

the heat radiation film is provided on an opposite face of the heater to the heat conductive member.

Images