阅读说明：本技术 光学装置 (Optical device ) 是由 渡边雅志 福田浩太郎 冈本拓巳 小仓太郎 于 2019-10-17 设计创作，主要内容包括：光学装置具备：感知通过了具有透光性的检测面(43)的光的传感器部(41)；以及透光性膜加热器(30),其具有与具有所述检测面的光学窗(42)相邻配置并加热所述光学窗的加热部(35)。所述透光性膜加热器具有如下温度分布：所述加热部中的位于以所述检测面的中心线(CL)为中心的径向外侧的外侧区域的温度比所述加热部中的相比所述外侧区域位于所述检测面的中心侧的区域温度高。(The optical device includes: a sensor unit (41) for sensing light that has passed through a detection surface (43) having translucency; and a light-transmitting film heater (30) having a heating unit (35) that is disposed adjacent to an optical window (42) having the detection surface and heats the optical window. The light-transmissive film heater has the following temperature distribution: the temperature of an outer region of the heating unit located radially outward of a Center Line (CL) of the detection surface is higher than the temperature of a region of the heating unit located more toward the center of the detection surface than the outer region.)

1. An optical device is provided with:

a sensor unit (41) that senses light that has passed through a light-transmissive detection surface (43); and

a light-transmissive film heater (30) having a heating section (35) that is disposed adjacent to an optical window (42) having the detection surface and heats the optical window,

the light-transmissive film heater has the following temperature distribution: the temperature of an outer region of the heating unit located radially outward of a Center Line (CL) of the detection surface is higher than the temperature of a region of the heating unit located more toward the center of the detection surface than the outer region.

2. The optical device according to claim 1,

the light-transmitting film heater includes:

a first electrode (31) disposed radially outward of a center line of the detection surface in the heating portion;

a second electrode (32) disposed in the heating portion so as to sandwich the detection surface from both sides together with the first electrode;

a third electrode (33) disposed radially outward of the detection surface on the first electrode side in the heating portion; and

a fourth electrode (34) disposed radially outward of the detection surface from the second electrode side in the heating portion,

the heating section has: a first heat generation region (E1) that generates heat according to a potential difference between the first electrode and the second electrode; a second heat generation region (E2) that generates heat according to a potential difference between the first electrode and the third electrode; and a third heat generation region (E3) that generates heat in accordance with a potential difference between the second electrode and the fourth electrode, the heat generation temperatures of the second heat generation region and the third heat generation region being higher than the heat generation temperature of the first heat generation region.

3. The optical device according to claim 2,

the first electrode and the second electrode are disposed at the same position in the thickness direction in the heating portion,

the first electrode and the third electrode are disposed at different positions in the thickness direction of the heating portion, and the second electrode and the fourth electrode are disposed at different positions in the thickness direction of the heating portion.

4. The optical device according to any one of claims 1 to 3,

the light-transmitting film heater includes a hot-wire heater (38) that heats the outer region radially outward of the center line of the detection surface.

5. The optical device according to claim 1,

the light-transmitting film heater includes:

a first electrode (31) disposed radially outward of a center line of the detection surface in the heating portion;

a second electrode (32) disposed in the heating portion so as to sandwich the detection surface from both sides together with the first electrode;

a third electrode (33) disposed radially outward of the detection surface on the first electrode side in the heating portion; and

a fourth electrode (34) disposed radially outward of the detection surface from the second electrode side in the heating portion,

the heating section has: a first heating unit (351) that generates heat in accordance with a potential difference between the first electrode and the second electrode; a second heating section (352), the second heating section (352) generating heat according to a potential difference between the first electrode and the third electrode; and a third heating unit (353) that generates heat in accordance with a potential difference between the second electrode and the fourth electrode, wherein a resistance value of the second heating unit based on the first electrode and the third electrode and a resistance value of the third heating unit based on the second electrode and the fourth electrode are larger than a resistance value of the first heating unit based on the first electrode and the second electrode.

6. The optical device according to claim 5,

the second heating unit and the third heating unit are formed of the same material as the first heating unit, and the length of the second heating unit and the third heating unit in the thickness direction is shorter than the length of the first heating unit in the thickness direction.

7. The optical device according to claim 5 or 6,

the second heating unit and the third heating unit are formed of the same material as the first heating unit, and at least one of the second heating unit and the third heating unit is provided with a notch (3521, 3531) for extending a current path length of a current flowing through at least one of the second heating unit and the third heating unit.

8. The optical device according to claim 5,

the second heating portion and the third heating portion are formed of a material different from the first heating portion.

9. An optical device, characterized in that,

the disclosed device is provided with: a light-transmissive film heater (30) that has a heating unit (35) that is disposed adjacent to an optical window (42) having light-transmissive properties and that heats the optical window; and a heat generating part (38, E2, E3) for generating heat in a predetermined region,

the light-transmitting film heater includes:

a first electrode (31) disposed radially outward of a Center Line (CL) of a predetermined region of the optical window in the heating section; and

a second electrode (32) disposed in the heating portion so as to sandwich a predetermined region of the optical window from both sides together with the first electrode,

the heating portion has a first heat generation region (E1) that generates heat according to a potential difference between the first electrode and the second electrode,

the heat generating portion generates heat in an outer region located radially outward of a center line of a predetermined region of the optical window.

10. The optical device according to claim 9,

the heat generating portion is constituted by a hot wire heater.

11. The optical device according to claim 9,

the light-transmitting film heater includes:

a third electrode (33) disposed radially outward of the heating portion on the first electrode side with respect to a center line of a predetermined region of the optical window; and

a fourth electrode (34) disposed radially outward of the heating portion on the second electrode side with respect to a center line of a predetermined region of the optical window,

the heating section has: the first heat generation area (E1); a second heat generation region (E2) that generates heat according to a potential difference between the first electrode and the third electrode; and a third heat generation region (E3) that generates heat according to a potential difference between the second electrode and the fourth electrode,

the heat generation portion causes the second heat generation region (E2) and the third heat generation region (E3) to generate heat as the outer regions.

12. The optical device according to claim 9,

the light-transmitting film heater includes:

a third electrode (33) disposed radially outward of the heating portion on the first electrode side with respect to a center line of a predetermined region of the optical window; and

a fourth electrode (34), wherein the fourth electrode (34) is arranged on the heating portion more toward the second electrode than the second electrode is arranged on the radial outer side with respect to the center line of the predetermined region of the optical window as the center,

the heating section has: the first heat generation area (E1); a second heat generation region (E2) that generates heat according to a potential difference between the first electrode and the third electrode; and a third heat generation region (E3) that generates heat according to a potential difference between the second electrode and the fourth electrode,

the first electrode and the second electrode are disposed at the same position in the thickness direction in the heating portion,

the first electrode and the third electrode are disposed at different positions in a thickness direction in the heating portion,

the second electrode and the fourth electrode are disposed at different positions in a thickness direction in the heating portion.

13. The optical device according to claim 10,

the hot wire heater is formed in a linear shape,

the first electrode is connected to one end of the hot wire heater, and the second electrode is connected to the other end of the hot wire heater.

14. The optical device according to any one of claims 9 to 13,

at least a portion of the first electrode and the second electrode function as a heater.

15. The optical device of claim 14,

at least one of the first electrode and the second electrode is formed in a linear shape and has a first electrode width and a second electrode width shorter than the first electrode width,

a portion of at least one of the first electrode and the second electrode, which has a width corresponding to the width of the second electrode, functions as the heater.

16. The optical device of claim 14,

at least one of the first electrode and the second electrode has a portion formed of a low-resistance material and a portion formed of a high-resistance material having a higher resistance than the low-resistance material,

a portion formed of the high-resistance material in at least one of the first electrode and the second electrode functions as the heater.

17. The optical device of claim 14,

the heat generating portion is disposed so as to surround a periphery of the predetermined region of the optical window except for a part of the periphery of the predetermined region of the optical window,

at least one of the first electrode and the second electrode is disposed in a part of a periphery of a predetermined region of the optical window, the part functioning as the heater.

Technical Field

The present invention relates to an optical device.

Background

Conventionally, there is a device including a light transmission sensor array disposed on a window glass of a vehicle and a planar overheat membrane disposed on the light transmission sensor array (for example, see patent document 1). The device prevents dew condensation and the like on the light-transmitting sensor array by heating the light-transmitting sensor array with a superheatable film.

Documents of the prior art

Patent document

Patent document 1: japanese Kokai publication No. 2012-530646

Disclosure of Invention

According to the study of the inventors of the present application, in the planar superheatable film as described in patent document 1, when the window glass is cooled, heat is taken away from three directions of the two planes and the side surfaces of the superheatable film. In this case, heat is uniformly removed from both flat surfaces of the superheatable film over the entire surface of each of the superheatable film, but heat is removed from the peripheral edge portion of the superheatable film in the peripheral edge portion of the superheatable film. Therefore, for example, when the amount of heat generation is reduced, fog is generated from the peripheral edge portion of the overheating capable film. The purpose of the present invention is to further suppress the generation of mist.

According to one aspect of the present invention, an optical device includes a sensor unit that senses light passing through a detection surface having translucency. The optical device further includes a light-transmissive film heater having a heating portion disposed adjacent to the optical window having the detection surface and heating the optical window. Further, the light transmissive film heater has the following temperature distribution: the temperature of an outer region of the heating portion located radially outward of the center line of the detection surface is higher than the temperature of a region of the heating portion located more toward the center of the detection surface than the outer region.

According to such a structure, the light-transmissive film heater has the following temperature distribution: the temperature of an outer region of the heating portion located radially outward of the center line of the detection surface is higher than the temperature of a region of the heating portion located more toward the center of the detection surface than the outer region. Therefore, the generation of mist from the peripheral edge portion of the heating portion can be suppressed, and the generation of mist can be further suppressed.

In addition, according to another aspect of the present invention, an optical device includes: a light-transmissive film heater including a heating portion that is disposed adjacent to the optical window having light-transmittance and heats the optical window; and a heat generating portion that generates heat in the predetermined region. Further, the light-transmissive film heater includes: a first electrode disposed radially outward of a center line of a predetermined region of the optical window in the heating portion; and a second electrode arranged in the heating portion so as to sandwich a predetermined region of the optical window from both sides together with the first electrode, the heating portion having a first heat generation region that generates heat in accordance with a potential difference between the first electrode and the second electrode, the heat generation portion generating heat in an outer region located radially outward of the first heat generation region with respect to a center line of the predetermined region of the optical window as a center.

According to such a configuration, the heating portion has a first heat generation region that generates heat in accordance with a potential difference between the first electrode and the second electrode, and the heat generation portion generates heat in an outer region located radially outward of the first heat generation region with respect to a center line of the predetermined region of the optical window as a center. Therefore, the generation of mist from the peripheral edge portion of the heating portion can be suppressed, and the generation of mist can be further suppressed.

The parenthesized reference numerals attached to the respective components and the like indicate an example of correspondence between the components and the like and specific components and the like described in the embodiments described later.

The parenthesized reference numerals attached to the respective components and the like indicate an example of correspondence between the components and the like and specific components and the like described in the embodiments described later.

Drawings

Fig. 1 is a diagram showing a configuration of an optical device according to a first embodiment.

Fig. 2 is a diagram showing the structure of a light-transmissive film heater of the optical device according to the first embodiment.

Fig. 3 is a diagram showing a configuration of a light-transmissive film heater of an optical device according to a second embodiment.

Fig. 4 is a diagram showing a heat generation region of the optical device according to the second embodiment.

Fig. 5 is a diagram showing a configuration of a light-transmissive film heater of an optical device according to a third embodiment.

Fig. 6 is a diagram showing a configuration of a light-transmissive film heater of an optical device according to a fourth embodiment.

Fig. 7 is a diagram showing a configuration of a light-transmissive film heater of an optical device according to a fifth embodiment.

Fig. 8 is a diagram showing a configuration of a light-transmissive film heater of an optical device according to a sixth embodiment.

Fig. 9 is a diagram showing a configuration of a light-transmissive film heater of an optical device according to a seventh embodiment.

Fig. 10 is a diagram showing a configuration of a light-transmissive film heater of an optical device according to an eighth embodiment.

Fig. 11 is a diagram showing a configuration of a light-transmissive film heater of an optical device according to a ninth embodiment.

Fig. 12 is a diagram showing a configuration of a light-transmissive film heater of an optical device according to a tenth embodiment.

Detailed Description

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following embodiments, the same or equivalent portions are denoted by the same reference numerals in the drawings.

(first embodiment)

An optical device according to a first embodiment will be described with reference to fig. 1 to 2. As shown in fig. 1, the optical device 1 includes an imaging device 40, a transparent film heater 30, and a control unit 50. The optical device 1 of the present embodiment captures an image by the imaging device 40.

The imaging device 40 includes an optical window 42 and a sensor unit 41. The planar optical window 42 is provided with a light-transmissive detection surface 43. The center line CL of the detection surface 43 is perpendicular to the planar optical window 42.

The sensor unit 41 senses light passing through the detection surface 43. The sensor unit 41 is formed of an image sensor such as a CCD (charge-Coupled device) or a CMOS (Complementary Metal-Oxide-Semiconductor). The imaging device 40 sends the captured image to the control unit 50 through the sensor unit 41.

The light-transmissive film heater 30 includes a first electrode 31, a second electrode 32, a heating unit 35, and a hot wire heater 38. The first electrode 31 and the second electrode 32 are made of a metal having conductivity. The first electrode 31 and the second electrode 32 are respectively formed in a linear shape. The first electrode 31 and the second electrode 32 are formed on one surface of the heating portion 35 by printing or the like. The first electrode 31 and the second electrode 32 are arranged to avoid the detection surface 43. Specifically, the first electrode 31 and the second electrode 32 are disposed so as to sandwich the detection surface 43 from the outside in the radial direction around the center line CL of the detection surface 43. The first electrode 31 and the second electrode 32 are connected to the control unit 50.

The heating portion 35 is disposed adjacent to a surface of the optical window 42 opposite to the surface facing the sensor portion 41. That is, the heating unit 35 is disposed adjacent to the optical window 42 having the detection surface 43, and heats the optical window 42.

The heating unit 35 can be formed of a transparent conductive film, for example. The transparent conductive film generates heat by applying current to the transparent conductive film via the first electrode 31 and the second electrode 32. The thickness of the heating part 35 is uniform. The heating unit 35 is homogeneous.

The hot wire heater 38 is disposed in an outer region radially outside the detection surface 43. The hot wire heater 38 is formed along the peripheral edge of the heating unit 35. The hot wire heater 38 is formed in a linear shape. The hot wire heater 38 generates heat by joule heat generated when current flows through the hot wire heater 38.

In the transparent film heater 30, the hot wire heater 38 is formed along the peripheral edge portion of the heating section 35, and has the following temperature distribution: the temperature of the outer region of the heating portion 35 radially outside the detection surface 43 is higher than the temperature of the region of the heating portion 35 closer to the center of the detection surface 43 than the outer region.

The optical device 1 of the present embodiment includes a sensor unit 41, and the sensor unit 41 senses light passing through a detection surface 43 having translucency. The optical detection device further includes a light-transmissive film heater 30 and a hot-wire heater 38 as a heat generating portion for generating heat in a predetermined region, and the light-transmissive film heater 30 has a heating portion 35 which is disposed adjacent to an optical window 42 having a detection surface 43 and heats the optical window 42.

Further, the light transmissive film heater 30 includes: a first electrode 31, the first electrode 31 being disposed radially outward of the center line of the detection surface 43 in the heating portion 35; and a second electrode 32, the second electrode 32 being disposed in the heating portion 35 so as to sandwich the detection surface 43 from both sides together with the first electrode 31. In addition, the heating part 35 has a first heat generation region E1, and the first heat generation region E1 generates heat according to a potential difference between the first electrode 31 and the second electrode 32. The hot wire heater 38 as a heat generating portion generates heat in an outer region located radially outward of the first heat generation region E1 with respect to the center line CL of the detection surface 43 as a center.

The control unit 50 is configured as a computer including a CPU, a memory, an I/O, and the like, and the CPU performs various processes according to a program stored in the memory.

The processing of the control unit 50 is, for example, the following processing: when it is determined that the fog is generated on the detection surface 43 based on the image input from the imaging device 40, a predetermined voltage is applied between the first electrode 31 and the second electrode 32 of the transparent film heater 30, and the energization of the hot wire heater 38 is started.

When a predetermined voltage is applied between the first electrode 31 and the second electrode 32 of the transparent film heater 30 by the control section 50, the heating section 35 generates heat. Further, when the control unit 50 starts the energization of the hot wire heater 38, the hot wire heater 38 generates heat. The hot wire heater 38 heats the outer region radially outward of the center line of the detection surface 43.

The hot wire heater 38 is formed along the peripheral edge portion of the heating portion 35, and has the following temperature distribution: the temperature of the outer region of the heating portion 35 radially outside the detection surface 43 is higher than the temperature of the region of the heating portion 35 closer to the center of the detection surface 43 than the outer region. This suppresses the generation of mist from the peripheral edge of the heating section 35.

As described above, the optical device of the present embodiment includes the sensor portion 41, and the sensor portion 41 senses light passing through the detection surface 43 having translucency. Further, the optical detection device is provided with a light-transmissive film heater 30, the light-transmissive film heater 30 having a heating section 35, and the heating section 35 is disposed adjacent to an optical window 42 having a detection surface and heats the optical window. Further, the light transmissive film heater 30 has the following temperature distribution: the temperature of the outer region of the heating portion 35 located radially outward of the center line CL of the detection surface 43 is higher than the temperature of the region of the heating portion 35 located more outward than the center of the detection surface.

According to the above structure, the light-transmissive film heater 30 has the following temperature distribution: the temperature of the outer region of the heating portion 35 located radially outward of the center line CL of the detection surface 43 is higher than the temperature of the region of the heating portion 35 located closer to the center of the detection surface 43 than the outer region. Therefore, the generation of mist from the peripheral portion of the heating portion 35 can be suppressed, and the generation of mist can be further suppressed.

The light-transmissive film heater 30 includes a hot wire heater 38 that heats an outer region radially outward of the center line of the detection surface 43.

In this way, the light-transmissive film heater 30 can include the hot wire heater 38 that heats the radially outer region around the center line CL of the detection surface 43.

The optical device 1 of the present embodiment includes a light-transmissive film heater 30 and a heat wire heater 38 as a heat generating portion for generating heat in a predetermined region, and the light-transmissive film heater 30 includes a heating portion 35 which is disposed adjacent to the light-transmissive optical window 42 and heats the light-transmissive optical window 42.

The light-transmissive film heater 30 includes a first electrode 31, and the first electrode 31 is disposed radially outward of the center line of the predetermined region of the optical window 42 in the heating unit 35. The second electrode 32 is provided, and the second electrode 32 is disposed in the heating portion 35 so as to sandwich a predetermined region of the optical window 42 from both sides together with the first electrode 31. In addition, the heating part 35 has a first heat generation region E1, and the first heat generation region E1 generates heat according to a potential difference between the first electrode 31 and the second electrode 32. The hot wire heater 38 generates heat in an outer region located radially outward of the first heat generation region E1 with respect to the center line of the predetermined region of the optical window 42 as the center. The center line of the predetermined region of the optical window 42 coincides with the center line CL of the detection surface 43.

According to such a configuration, the heating part 35 has the first heat generation region E1, and the first heat generation region E1 generates heat according to a potential difference between the first electrode 31 and the second electrode 32. Further, the hot-wire heater 38 as the heat generating portion generates heat in the outer region located radially outward of the first heat generating region E1 with respect to the center line CL of the predetermined region of the optical window 42 as the center, and therefore generation of mist from the peripheral portion of the heating portion 35 can be suppressed, and generation of mist can be further suppressed.

(second embodiment)

An optical device 1 according to a second embodiment will be described with reference to fig. 3 to 4. The optical device 1 of the present embodiment includes first to fourth electrodes 31 to 34 and a heating unit 35.

The first electrode 31 is disposed radially outward of the heating portion 35 with respect to the center line CL of the detection surface 43. The second electrode 32 is disposed in the heating portion 35 so as to sandwich the detection surface 43 from both sides together with the first electrode 31.

The third electrode 33 is disposed radially outward of the detection surface 43 on the first electrode 31 side in the heating unit 35. The fourth electrode 34 is disposed radially outward of the detection surface 43 on the second electrode 32 side in the heating portion 35. The first electrode 31 to the fourth electrode 34 are each formed in a linear shape. The first electrode 31 to the fourth electrode 34 are parallel to each other.

In addition, the interval between the first electrode 31 and the third electrode 33 is the same as the interval between the second electrode 32 and the fourth electrode 34. In addition, the interval between the first electrode 31 and the third electrode 33 and the interval between the second electrode 32 and the fourth electrode 34 are shorter than the interval between the first electrode 31 and the second electrode 32, respectively.

In the present embodiment, the potential of the first electrode 31 is controlled to 0 v, the potential of the second electrode 32 is controlled to 12 v, the potential of the third electrode 33 is controlled to 12 v, and the potential of the fourth electrode 34 is controlled to 0 v.

As shown in fig. 4, the heating part 35 has a first heat generation region E1, and the first heat generation region E1 generates heat according to a potential difference between the first electrode 31 and the second electrode 32. In addition, the heating part 35 has a second heat generation region E2, and the second heat generation region E2 generates heat according to a potential difference between the first electrode 31 and the third electrode 33. In addition, the heating portion 35 has a third heat generation region E3, and the third heat generation region E3 generates heat according to a potential difference between the second electrode 32 and the fourth electrode 34. Further, the heat generation temperatures of the second heat generation region E2 and the third heat generation region E3 are higher than the heat generation temperature of the first heat generation region E1.

Thus, the light-transmissive film heater 30 has the following temperature distribution: the temperature of the outer region of the heating portion 35 radially outside the detection surface 43 is higher than the temperature of the region of the heating portion 35 closer to the center of the detection surface 43 than the outer region. Therefore, the generation of mist from the peripheral edge portion of the heating portion can be suppressed, and the generation of mist can be further suppressed.

The light transmissive film heater of the present embodiment includes the first electrode 31, and the first electrode 31 is disposed radially outward of the center line of the detection surface 43 in the heating unit 35. Further, the second electrode 32 is provided, and the second electrode 32 is disposed in the heating portion 35 so as to sandwich the detection surface 43 from both sides together with the first electrode 31. The third electrode 33 is provided, and the third electrode 33 is arranged radially outward of the detection surface 43 on the first electrode 31 side in the heating unit 35. The fourth electrode 34 is provided, and the fourth electrode 34 is arranged radially outward of the detection surface 43 on the second electrode 32 side in the heating unit 35.

In addition, the heating part 35 has a first heat generation region E1, and the first heat generation region E1 generates heat according to a potential difference between the first electrode 31 and the second electrode 32. In addition, there is a second heat generation region E2, which generates heat according to the potential difference between the first electrode 31 and the third electrode 33, E2. In addition, there is a third heat generation region E3, the third heat generation region E3 generates heat according to the potential difference between the second electrode 32 and the fourth electrode 34. The heat generating portion generates heat in the second heat generating region E2 and the third heat generating region E3 as outer regions.

According to such a configuration, the heat generating portion generates heat with the second heat generating region E2 and the third heat generating region E3 as outer regions, and therefore, generation of mist from the peripheral edge portion of the heating portion 35 can be suppressed, and generation of mist can be further suppressed.

In the present embodiment, the same effects as those achieved by the configuration common to the first embodiment can be obtained as in the first embodiment.

(third embodiment)

An optical device 1 according to a third embodiment will be described with reference to fig. 5. The first to fourth electrodes 31 to 34 of the optical device 1 according to the second embodiment are arranged on the same plane. In contrast, in the optical device 1 of the present embodiment, the first electrode 31 and the third electrode 33 are disposed at different positions in the thickness direction in the heating portion 35, and the second electrode 32 and the fourth electrode 34 are disposed at different positions in the thickness direction in the heating portion 35.

The heating unit 35 is formed in a thin plate shape extending along an X-Y plane defined by the X axis and the Y axis. The heating portion 35 has a thickness in the Z-axis direction orthogonal to the X-Y plane.

A protective layer 36 is disposed on one surface of the heating portion 35, and a protective layer 37 is disposed on the opposite surface of the heating portion 35.

The first electrode 31 and the second electrode 32 are disposed on the surface of the heating portion 35 on the protective layer 37 side, and the third electrode 33 and the fourth electrode 34 are disposed on the surface of the heating portion 35 on the protective layer 36 side.

That is, the first electrode 31 and the second electrode 32 are disposed at the same position in the thickness direction in the heating portion 35. The first electrode 31 and the third electrode 33 are disposed at different positions in the thickness direction of the heating portion 35, and the second electrode 32 and the fourth electrode 34 are disposed at different positions in the thickness direction of the heating portion 35.

The heat generation temperature of the heat generation region that generates heat due to the potential difference between the first electrode 31 and the third electrode 33 and the heat generation region that generates heat due to the potential difference between the second electrode 32 and the fourth electrode 34 is higher than the heat generation temperature of the heat generation region that generates heat due to the potential difference between the first electrode 31 and the second electrode 32.

Thus, the light-transmissive film heater 30 has the following temperature distribution: the temperature of the outer region of the heating portion 35 radially outside the detection surface 43 is higher than the temperature of the region of the heating portion 35 closer to the center of the detection surface 43 than the outer region. Therefore, the generation of mist from the peripheral edge portion of the heating portion can be suppressed, and the generation of mist can be further suppressed.

The light transmissive film heater of the present embodiment includes the third electrode 33, and the third electrode 33 is disposed radially outward of the detection surface 43 on the side of the first electrode 31 in the heating unit 35. The fourth electrode 34 is provided, and the fourth electrode 34 is arranged radially outward of the detection surface 43 on the second electrode 32 side in the heating unit 35.

In addition, the heating part 35 has a first heat generation region E1, and the first heat generation region E1 generates heat according to a potential difference between the first electrode 31 and the second electrode 32. In addition, there is a second heat generation region E2, which generates heat according to the potential difference between the first electrode 31 and the third electrode 33, E2. In addition, there is a third heat generation region E3, the third heat generation region E3 generates heat according to the potential difference between the second electrode 32 and the fourth electrode 34.

The first electrode 31 and the second electrode 32 are disposed at the same position in the thickness direction in the heating portion 35. The first electrode 31 and the third electrode 33 are disposed at different positions in the thickness direction of the heating portion 35, and the second electrode 32 and the fourth electrode 34 are disposed at different positions in the thickness direction of the heating portion 35. The heat generating portion generates heat in the second heat generating region E2 and the third heat generating region E3 as outer regions.

According to such a configuration, the heat generating portion generates heat with the second heat generating region E2 and the third heat generating region E3 as outer regions, and therefore, generation of mist from the peripheral edge portion of the heating portion 35 can be suppressed, and generation of mist can be further suppressed.

In the present embodiment, the same effects as those achieved by the configuration common to the first embodiment can be obtained as in the first embodiment.

In the light-transmissive film heater 30 of the present embodiment, the first electrode 31 and the third electrode 33 are disposed at different positions in the thickness direction in the heating portion 35, and the second electrode 32 and the fourth electrode 34 are disposed at different positions in the thickness direction in the heating portion 35. That is, the first to fourth electrodes 31 to 31 are arranged three-dimensionally. Therefore, the heating portion 35 can be made space-saving.

(fourth embodiment)

An optical device 1 according to a fourth embodiment will be described with reference to fig. 6. The optical device 1 of the present embodiment includes: first to fourth electrodes 31 to 34; and a light-transmissive film heater 30, the light-transmissive film heater 30 having a heating portion 35 extending in the X-Y plane direction.

The first electrode 31 is disposed radially outward of the heating portion 35 with respect to the center line CL of the detection surface 43. The second electrode 32 is disposed in the heating portion 35 so as to sandwich the detection surface 43 from both sides together with the first electrode 31.

The third electrode 33 is disposed radially outward of the detection surface 43 on the first electrode 31 side in the heating unit 35. The fourth electrode 34 is disposed radially outward of the detection surface 43 on the second electrode 32 side in the heating portion 35. The first electrode 31 to the fourth electrode 34 are each formed in an L shape.

In addition, the interval between the first electrode 31 and the third electrode 33 is the same as the interval between the second electrode 32 and the fourth electrode 34. In addition, the interval between the first electrode 31 and the third electrode 33 and the interval between the second electrode 32 and the fourth electrode 34 are shorter than the interval between the first electrode 31 and the second electrode 32, respectively.

In the present embodiment, the potential of the first electrode 31 is controlled to 0 v, the potential of the second electrode 32 is controlled to 12 v, the potential of the third electrode 33 is controlled to 12 v, and the potential of the fourth electrode 34 is controlled to 0 v.

The heating part 35 has a first heating part 351, and the first heating part 351 generates heat according to a potential difference between the first electrode 31 and the second electrode 32. The heating portion 35 has a second heating portion 352, and the second heating portion 352 generates heat by a potential difference between the first electrode 31 and the third electrode 33. The heating unit 35 has a third heating unit 353, and the third heating unit 353 generates heat according to a potential difference between the second electrode 32 and the fourth electrode 34. The second heating part 352 and the third heating part 353 are respectively formed in an L shape. The second heating unit 352 and the third heating unit 353 form a U-shaped heating unit. The second heating portion 352 and the third heating portion 353 are disposed so as to surround the first heating portion 351. In fig. 6, the second heating unit 352 and the third heating unit 353 are hatched.

The first heating unit 351, the second heating unit 352, and the third heating unit 353 are formed of the same material.

According to this configuration, the translucent film heater 30 has a temperature distribution in which the temperature of the outer region of the heating portion 35 located radially outward of the center line CL of the detection surface 43 is higher than the temperature of the region of the heating portion 35 located more outward than the center of the detection surface 43. Therefore, the generation of mist from the peripheral portion of the heating portion 35 can be suppressed, and the generation of mist can be further suppressed.

In addition, the interval between the first electrode 31 and the third electrode 33 and the interval between the second electrode 32 and the fourth electrode 34 are shorter than the interval between the first electrode 31 and the second electrode 32, respectively. Therefore, the heat generation amounts of the second heating unit 352 and the third heating unit 353 may become excessive, which may cause a failure or the like.

Therefore, in the optical device 1, the resistance value of the second heating portion 352 formed by the first electrode 31 and the third electrode 33 and the resistance value of the third heating portion 353 formed by the second electrode 32 and the fourth electrode 34 are smaller than the resistance value of the first heating portion 351 formed by the first electrode 31 and the second electrode 32.

Specifically, the lengths of the second heating section 352 and the third heating section 353 in the thickness direction are shorter than the length of the first heating section 351 in the thickness direction. Accordingly, the resistance values of the second heating portion 352 and the third heating portion 353 are smaller than the resistance value of the first heating portion 351, and the amounts of heat generation of the second heating portion 352 and the third heating portion 353 are suppressed.

In the present embodiment, the same effects as those achieved by the configuration common to the first embodiment can be obtained as in the first embodiment.

(fifth embodiment)

An optical device 1 according to a fifth embodiment will be described with reference to fig. 7. In the fourth embodiment, the resistance value of the second heating portion 352 based on the first electrode 31 and the third electrode 33 and the resistance value of the third heating portion 353 based on the second electrode 32 and the fourth electrode 34 are set to be larger than the resistance value of the first heating portion 351 based on the first electrode 31 and the second electrode 32. Specifically, the lengths of the second heating section 352 and the third heating section 353 in the thickness direction are made shorter than the length of the first heating section 351 in the thickness direction.

In contrast, in the optical device 1, the resistance value of the second heating portion 352 formed by the first electrode 31 and the third electrode 33 and the resistance value of the third heating portion 353 formed by the second electrode 32 and the fourth electrode 34 are larger than the resistance value of the first heating portion 351 formed by the first electrode 31 and the second electrode 32. Specifically, the second heating unit 352 and the third heating unit 353 are formed with cutouts 3521 and 3531 for extending the current path length of the current flowing through the second heating unit 352 and the third heating unit 353.

In fig. 7, the first to fourth electrodes 31 to 34, the second heating unit 352, and the third heating unit 353 are hatched. The first heating unit 351, the second heating unit 352, and the third heating unit 353 are formed of the same material.

The optical device 1 of the present embodiment includes a first heating unit 351, a second heating unit 352, and a third heating unit 353, which are formed of the same material and have a film shape. Thereafter, a slit 3521 is formed at the second heating part 352 and a slit 3531 is formed at the third heating part 353 by laser processing. The slits 3521 and 3531 are formed to extend in the X-axis direction, respectively.

The resistance value of the second heating portion 352 formed by the first electrode 31 and the third electrode 33 is increased by the slit 3521, and the resistance value of the third heating portion 353 formed by the second electrode 32 and the fourth electrode 34 is increased by the slit 3531.

Accordingly, the resistance value of the second heating portion 352 based on the first electrode 31 and the third electrode 33 and the resistance value of the third heating portion 353 based on the second electrode 32 and the fourth electrode 34 are larger than the resistance value of the first heating portion 351 based on the first electrode 31 and the second electrode 32. Further, the amounts of heat generation of the second heating section 352 and the third heating section 353 are suppressed.

In the present embodiment, the slit 3521 and the slit 3531 are formed to extend in the X-axis direction, but the slit 3521 and the slit 3531 may be formed to have a complicated bend such as a zigzag structure.

(sixth embodiment)

An optical device 1 according to a sixth embodiment will be described with reference to fig. 8. In the optical device 1 of the present embodiment, the high-resistance heat generating portion 323 having a high resistance is formed in a part of the second electrode 32. That is, the second electrode 32 has a low-resistance portion 321 having a low resistance and a high-resistance heat generating portion 323 having a high resistance. The low resistance portion 321 and the high resistance heat generating portion 323 are formed in a linear shape and are made of the same material. The line width of the high resistance heat generating portion 323 is shorter than the line width of the low resistance portion 321, and the cross-sectional area of the current path of the high resistance heat generating portion 323 is smaller than the cross-sectional area of the current path of the low resistance portion 321. Thus, the resistance value of the high-resistance heat generating portion 323 is larger than that of the low-resistance portion 321.

The high-resistance heat generating portion 323 is disposed in an outer region located radially outward of the first heat generating region E1 with respect to the center line CL of the detection surface 43 as the center, and generates heat in the outer region. That is, the high-resistance heat generating portion 323 which is a part of the second electrode 32 functions as a heater.

When a predetermined voltage is applied between the first electrode 31 and the second electrode 32 of the transparent film heater 30 by the control section 50, the heating section 35 generates heat when the transparent conductive film constituting the control section 50 is energized via the first electrode 31 and the second electrode 32. At this time, a current flows through the high resistance heat generating portion 323, and the high resistance heat generating portion 323 also generates heat. In addition, the low-resistance portion 321 does not generate heat. Further, when the control unit 50 starts the energization of the hot wire heater 38, the hot wire heater 38 also generates heat.

As described above, a part of the second electrode 32 of the optical device of the present embodiment functions as a heater. This enables downsizing as compared with a case where the heater is configured by using another member.

In the present embodiment, a part of the second electrode 32 is configured to function as a heater, but a part of the first electrode 31 may be configured to function as a heater. In addition, at least a part of the first electrode 31 and the second electrode 32 may be configured to function as a heater.

(seventh embodiment)

An optical device 1 according to a seventh embodiment will be described with reference to fig. 9. The optical device 1 of the present embodiment is different from the optical device 1 of the sixth embodiment in that the hot wire heater 38 is connected to the first electrode 31 and the second electrode 32. The second electrode 32 also differs in that a portion of the high-resistance heat generating portion 323 functioning as a heater is disposed in a part of the periphery of the optical window 42 having optical transparency.

The hot wire heater 38 is connected between the first electrode 31 and the second electrode 32. That is, the first electrode 31 is connected to one end of the hot wire heater 38, and the second electrode 32 is connected to the other end of the hot wire heater 38.

This makes it possible to share the connection part for supplying voltage to the first electrode 31 and the hot wire heater 38, and to share the connection part for supplying voltage to the second electrode 32 and the hot wire heater 38, thereby making it possible to downsize the optical device.

The hot-wire heater 38 as a heat generating portion is disposed so as to surround the periphery of the detection surface 43 except for a part of the periphery of the optical window 42 having optical transparency. In addition, a portion of the second electrode 32, which serves as a high-resistance heat generating portion 323 serving as a heater, is disposed in a part of the periphery of the optical window 42 having optical transparency.

Thus, the portion of the second electrode 32, which serves as the high-resistance heat generating portion 323, causes the hot wire heater 38 not to generate heat around the optical window 42 having light transmissivity, and therefore, the generation of mist from the peripheral portion of the heating portion 35 can be further suppressed.

(eighth embodiment)

An optical device 1 according to an eighth embodiment will be described with reference to fig. 10. In contrast to the optical device 1 of the first embodiment, the range in which the hot wire heater 38 of the optical device 1 of the present embodiment surrounds the detection surface 43 is increased.

The hot wire heater 38 of the present embodiment is disposed so as to surround substantially the entire detection surface 43. In fig. 10, an insulating layer, not shown, is disposed between the hot wire heater 38 and the second electrode 32 at a position X where the hot wire heater 38 and the second electrode 32 intersect, and the hot wire heater 38 and the second electrode 32 are insulated from each other by the insulating layer.

In this way, the hot wire heater 38 can be configured to surround substantially the entire circumference of the detection surface 43.

(ninth embodiment)

An optical device 1 according to a ninth embodiment will be described with reference to fig. 11. The optical device 1 of the present embodiment is different from the optical device 1 of the first embodiment in that the line width of the hot wire heater 38 is different depending on the position.

The hot wire heater 38 has: a first line wide portion 381, the first line wide portion 381 having a first electrode width; and a second line wide portion 382, the second line wide portion 382 having a second electrode width longer than the line width of the first electrode width. The first wire wide portion 381 and the second wire wide portion 382 are formed using the same material.

The second wire wide portion 382 has a larger heat capacity than the first wire wide portion 381, and therefore the temperature around the second wire wide portion 382 is higher than the temperature around the second wire wide portion 382. That is, the second wire wide portion 382 functions as a heater. Therefore, the second wire wide portion 382 is formed in the region of the heating portion 35 where the temperature is low, and the first wire wide portion 381 is disposed in the region of the heating portion 35 where the temperature is high, whereby the temperature unevenness of the heating portion 35 can be suppressed.

(tenth embodiment)

An optical device 1 according to a tenth embodiment will be described with reference to fig. 12. The optical device 1 of the present embodiment is different from the optical device of the first embodiment in the point that the hot wire heater 38 is connected to the first electrode 31 and the second electrode 32, and the first electrode 31 and the second electrode 32 are configured.

The hot wire heater 38 is connected between the first electrode 31 and the second electrode 32. That is, the first electrode 31 is connected to one end of the hot wire heater 38, and the second electrode 32 is connected to the other end of the hot wire heater 38.

This makes it possible to share the connection part for supplying voltage to the first electrode 31 and the hot wire heater 38, and to share the connection part for supplying voltage to the second electrode 32 and the hot wire heater 38, thereby making it possible to downsize the optical device.

The first electrode 31 has a low-resistance portion 311 formed using a low-resistance material and a high-resistance portion 312 formed using a high-resistance material having higher resistance than the low-resistance material.

The second electrode 32 has a low-resistance portion 321 formed using a low-resistance material and a high-resistance portion 322 formed using a high-resistance material having higher resistance than the low-resistance material.

Also, the high-resistance portion 312 of the first electrode 31 formed using a high-resistance material functions as a heater, and the high-resistance portion 312 of the 32 nd electrode formed using a high-resistance material functions as a heater.

As described above, by forming the first electrode 31 and the second electrode 32 using materials having different resistance values, a portion formed using a material having a large resistance value can function as a heater.

(other embodiments)

(1) In the above embodiments, the detection surface of the optical window 42 of the imaging device 40 is heated by the transparent film heater 30. In contrast, for example, the windshield of the vehicle may be regarded as the optical window 42, and a predetermined region of the optical window 42 may be heated by the heating portion 35 of the transparent film heater 30.

(2) In the present embodiment, the optical device 1 including the Imaging device 40 for capturing an image of the periphery of the vehicle is described, but the optical device 1 may be configured to include a distance sensor called a LIDAR (Laser Imaging Detection and Ranging), or the optical device 1 including a monitoring Imaging device or the like.

(3) In each of the above embodiments, the heating portion 35 is disposed adjacent to the surface of the optical window 42 opposite to the surface facing the sensor portion 41, but the heating portion 35 may be disposed adjacent to the surface of the optical window 42 facing the sensor portion 41.

(4) In each of the above embodiments, the interval between the first electrode 31 and the third electrode 33 is set to be the same as the interval between the second electrode 32 and the fourth electrode 34, but the interval between the first electrode 31 and the third electrode 33 may be set to be different from the interval between the second electrode 32 and the fourth electrode 34.

(5) In the first embodiment, the first electrode 31 to the second electrode 32 are formed in a linear shape, and in the second embodiment to the third embodiment, the first electrode 31 to the fourth electrode 34 are formed in a linear shape. In contrast, the first to second electrodes 31 to 32 and the third to fourth electrodes 33 to 34 may have shapes other than the linear shape.

(6) In the fourth to fifth embodiments, the first heating unit 351, the second heating unit 352, and the third heating unit 353 are formed of the same material, but the second heating unit 352 and the third heating unit 353 may be formed of a different material from the first heating unit 351.

(7) In the first embodiment, when the control unit 50 determines that the fog is generated on the detection surface 43 based on the image input from the imaging device 40, a predetermined voltage is applied between the first electrode 31 and the second electrode 32 of the transparent film heater 30, and the energization of the hot wire heater 38 is started.

On the other hand, the control unit 50 may detect the environmental conditions (temperature, humidity, and radiation amount) on both or one of the detection surfaces 43 and the detection temperature of the object to be heated, and calculate the condition for generating the mist on the detection surface 43 based on the detected environmental conditions and temperature. When the condition for generating the mist on the detection surface 43 is satisfied, a predetermined voltage may be applied between the first electrode 31 and the second electrode 32 of the light-transmissive film heater 30 to start the energization of the hot wire heater 38.

The present invention is not limited to the above-described embodiments, and can be modified as appropriate. The above embodiments are not independent of each other, and can be combined appropriately except when the combination is obviously impossible. In the above embodiments, the elements constituting the embodiments are not necessarily essential, except for cases where the elements are specifically and explicitly described as essential, and cases where the elements are apparently considered essential in principle. In the above embodiments, when numerical values such as the number, numerical value, amount, and range of the constituent elements of the embodiments are mentioned, the number is not limited to a specific number unless it is specifically stated explicitly to be necessary or it is obvious that the number is limited to a specific number in principle. In the above embodiments, when referring to the material, shape, positional relationship, and the like of the constituent elements and the like, the material, shape, positional relationship, and the like are not limited to those unless otherwise specifically indicated or limited to specific materials, shapes, positional relationship, and the like in principle.

(conclusion)

According to a first aspect shown in part or all of the above embodiments, the optical device of the present embodiment includes a sensor unit that senses light passing through a detection surface having translucency. The detection device further includes a light-transmissive film heater having a heating unit that is disposed adjacent to the optical window having the detection surface and heats the optical window. Further, the light transmissive film heater has the following temperature distribution: the temperature of an outer region of the heating portion located radially outward of the center line of the detection surface is higher than the temperature of a region of the heating portion located more toward the center of the detection surface than the outer region.

In addition, according to a second aspect, the light transmissive film heater includes a first electrode disposed radially outward of a center line of the detection surface in the heating portion. Further, the apparatus comprises: a second electrode arranged in the heating portion so as to sandwich the detection surface from both sides together with the first electrode; and a third electrode arranged radially outward of the detection surface on the first electrode side in the heating portion. The detection device further includes a fourth electrode disposed radially outward of the detection surface on the second electrode side in the heating portion.

The heating section includes: a first heat generation region that generates heat according to a potential difference between the first electrode and the second electrode; a second heat generation region that generates heat according to a potential difference between the first electrode and the third electrode; and a third heat generation region that generates heat according to a potential difference between the second electrode and the fourth electrode. The heat generation temperatures of the second heat generation region and the third heat generation region are higher than the heat generation temperature of the first heat generation region.

Therefore, the generation of mist from the peripheral edge portion of the heating portion can be suppressed, and the generation of mist can be further suppressed.

In addition, according to a third aspect, the first electrode and the second electrode are disposed at the same position in the thickness direction in the heating portion. The first electrode and the third electrode are disposed at different positions in the thickness direction of the heating portion, and the second electrode and the fourth electrode are disposed at different positions in the thickness direction of the heating portion.

The heat generation temperature of the heat generation region that generates heat by the potential difference between the first electrode and the third electrode and the heat generation region that generates heat by the potential difference between the second electrode and the fourth electrode is higher than the heat generation temperature of the heat generation region that generates heat by the potential difference between the first electrode and the second electrode.

That is, the first to fourth electrodes are arranged three-dimensionally. Therefore, the heating portion can be made space-saving.

In addition, according to a fourth aspect, the light transmissive film heater includes a hot wire heater that heats an outer region on the radially outer side with respect to the center line of the detection surface as a center.

In this way, the light-transmissive film heater may include a hot wire heater that heats an outer region radially outward of the center line of the detection surface.

In addition, according to a fifth aspect, the light transmissive film heater includes a first electrode disposed radially outward of a center line of the detection surface in the heating portion.

Further, the apparatus comprises: a second electrode arranged in the heating portion so as to sandwich the detection surface from both sides together with the first electrode; and a third electrode arranged radially outward of the detection surface on the first electrode side in the heating portion. The detection device further includes a fourth electrode disposed radially outward of the detection surface on the second electrode side in the heating portion.

Further, the heating section includes: a first heating section that generates heat according to a potential difference between the first electrode and the second electrode; and a second heating section that generates heat according to a potential difference between the first electrode and the third electrode.

In addition, a third heating section is provided, and the third heating section generates heat in accordance with a potential difference between the second electrode and the fourth electrode. The resistance value of the second heating portion based on the first electrode and the third electrode and the resistance value of the third heating portion based on the second electrode and the fourth electrode are larger than the resistance value of the first heating portion based on the first electrode and the second electrode.

Accordingly, the resistance values of the second heating unit and the third heating unit are larger than the resistance value of the first heating unit, and the amounts of heat generation of the second heating unit and the third heating unit can be suppressed.

In addition, according to a sixth aspect, the second heating section and the third heating section are formed of the same material as the first heating section, and the length of the second heating section and the third heating section in the thickness direction is shorter than the length of the first heating section in the thickness direction.

Accordingly, the resistance values of the second heating unit and the third heating unit are larger than the resistance value of the first heating unit 351, and the amounts of heat generation of the second heating unit 352 and the third heating unit can be suppressed.

In addition, according to a seventh aspect, the second heating section and the third heating section are formed of the same material as the first heating section. Further, a cutout for extending a current path length of a current flowing through at least one of the second heating unit and the third heating unit is formed in at least one of the second heating unit and the third heating unit.

Accordingly, the resistance value of the second heating portion based on the first electrode and the third electrode and the resistance value of the third heating portion based on the second electrode and the fourth electrode are larger than the resistance value of the first heating portion based on the first electrode and the second electrode, and the heat generation amounts of the second heating portion and the third heating portion can be suppressed.

In addition, according to an eighth aspect, the second heating section and the third heating section are formed of a different material from the first heating section. In this way, the second heating section and the third heating section can be formed of a different material from the first heating section.

Further, according to a ninth aspect, an optical device includes: a light-transmissive film heater having a heating portion that is disposed adjacent to the light-transmissive optical window and heats the optical window; and a heat generating portion that generates heat in the predetermined region. The heat generating unit is provided to generate heat in a predetermined region. The light-transmissive film heater further includes a first electrode disposed radially outward of a center line of the predetermined region of the optical window in the heating portion. The optical device further includes a second electrode disposed in the heating portion so as to sandwich a predetermined region of the optical window from both sides together with the first electrode. The heating unit has a first heat generation region that generates heat in accordance with a potential difference between the first electrode and the second electrode. The heat generating portion generates heat in an outer region located radially outward of a center line of the predetermined region of the optical window.

In addition, according to a tenth aspect, the light-transmissive film heater includes a hot wire heater that generates heat in an outer region radially outward of a center of the predetermined region of the optical window, and the heat generating portion is configured by the hot wire heater. In this way, the heat generating portion can be constituted by the hot wire heater.

In addition, according to an eleventh aspect, the light transmissive film heater includes a third electrode disposed radially outward of the heating portion on the first electrode side with respect to a center line of the predetermined region of the optical window. The optical window includes a first electrode disposed on the first electrode side in the heating section, and a second electrode disposed on the second electrode side in the heating section. In addition, the heating portion has a first heat generation region and a second heat generation region that generates heat according to a potential difference between the first electrode and the third electrode. In addition, a third heat generation region that generates heat according to a potential difference between the second electrode and the fourth electrode is provided. The heat generation portion generates heat in the second heat generation region and the third heat generation region as outer regions. In this way, the second heat generation region and the third heat generation region can be caused to generate heat as the outer regions.

In addition, according to a twelfth aspect, the transparent film heater includes a third electrode disposed radially outward of the heating portion on the first electrode side with respect to a center line of the predetermined region of the optical window. The optical window includes a first electrode disposed on the first electrode side in the heating section, and a second electrode disposed on the second electrode side in the heating section. In addition, the heating portion has a first heat generation region and a second heat generation region that generates heat according to a potential difference between the first electrode and the third electrode. In addition, a third heat generation region that generates heat according to a potential difference between the second electrode and the fourth electrode is provided. The first electrode and the second electrode are disposed at the same position in the thickness direction of the heating unit, the first electrode and the third electrode are disposed at different positions in the thickness direction of the heating unit, and the second electrode and the fourth electrode are disposed at different positions in the thickness direction of the heating unit.

That is, the first to fourth electrodes are arranged three-dimensionally. Therefore, the heating portion can be made space-saving.

In addition, according to a thirteenth aspect, the first electrode is connected to one end of the hot wire heater, and the second electrode is connected to the other end of the hot wire heater.

Accordingly, the connection portion for supplying voltage to the first electrode and the hot wire heater can be made common, and the connection portion for supplying voltage to the second electrode and the hot wire heater can be made common, so that the optical device can be downsized.

In addition, according to a fourteenth aspect, at least a part of the first electrode and the second electrode functions as a heater. Therefore, the heater can be made smaller than a case where the heater is formed by using another member.

In addition, according to a fifteenth aspect, at least one of the first electrode and the second electrode is formed in a linear shape, and has a first electrode width and a second electrode width shorter than the first electrode width. In addition, a portion of at least one of the first electrode and the second electrode, which has a width corresponding to the second electrode, functions as a heater.

In this way, the electrode width of the electrode is made short, and the portion having the short electrode width functions as a heater, so that the heater can be configured with a simple structure and low cost can be achieved.

In addition, according to a sixteenth aspect, at least one of the first electrode and the second electrode has a portion formed of a low-resistance material and a portion formed of a high-resistance material having higher resistance than the low-resistance material. In addition, a portion formed of a high-resistance material in at least one of the first electrode and the second electrode functions as a heater.

In this way, since the material constituting the electrode has a high resistance and functions as a heater, the heater can be constituted with a simple structure and low cost can be achieved.

Further, according to a seventeenth aspect, the heat generating portion is disposed so as to surround the periphery of the detection surface except for a part of the periphery of the predetermined region of the optical window, and the portion of at least one of the first electrode and the second electrode that functions as the heater is disposed at a part of the periphery of the predetermined region of the optical window.

Thus, the heat generating portion of at least one of the first electrode and the second electrode is disposed at a portion of the hot wire heater not surrounding the detection surface, and therefore, the generation of mist from the peripheral portion of the heating portion can be suppressed.