JP2020056858A - Imaging apparatus - Google Patents

Abstract

To provide an imaging apparatus capable of improving the response performance of an electrochromic device degraded in low temperature environment by solving problem in a conventional energization and heating manner that complicated configurations of element drive circuit and heating circuit and relatively large power consumption are required.SOLUTION: The imaging apparatus has an electrochromic device that includes: an image sensor; a pair of transparent electrode substrates; and an electrochromic media containing at least one kind of electrochromic material and a solvent disposed between the pair of transparent electrode substrates. The imaging apparatus also includes: a thermally conductive sealing member that is variable in volume and seals the electrochromic media; and a mechanism that performs thermal connection and interception with a heating element that becomes a high temperature during shooting operation.SELECTED DRAWING: Figure 3

Description

  The present invention relates to an imaging device using an electrochromic device that controls light intensity and color.

  An electrochromic device is a device having a pair of electrodes and an electrochromic layer disposed between the pair of electrodes.

  When a voltage is applied between a pair of electrodes of the electrochromic device to redox the electrochromic compound in the electrochromic layer, the spectral transmittance in the visible light region changes, thereby adjusting the amount of visible light passing through the electrochromic device. can do.

  2. Description of the Related Art In recent years, in a moving image photographing apparatus using a solid-state imaging device, a demand for a variable ND filter capable of adjusting the optical density steplessly has been increasing. Many optical elements using liquid crystal or inorganic electrochromic thin films have been proposed as optical elements for this purpose, but they are inferior to conventional fixed-density ND filters in terms of light amount adjustment range and reliability, and are widely used. Not popular.

  On the other hand, an optical element using organic electrochromic molecules has a wide range of light quantity adjustment and a relatively easy design of spectral transmittance, and is therefore promising as a variable ND filter used in an imaging device.

  An electrochromic element using an organic electrochromic molecule has an electrochemically active anodic material and a cathodic material between a pair of electrodes. At least one of them is configured as a material that exhibits an absorption band in a visible light region by electrochromic property, that is, electrochemical redox. At this time, on the pair of electrodes, an oxidizing reaction of the anodic material and a reducing reaction of the cathodic material occur at the same time, a closed circuit is formed in the element, and current flows.

  However, since an electrochromic device using organic electrochromic molecules utilizes a redox reaction of molecules in a solution phase, the response time for increasing or decreasing the optical density depends on the environmental temperature in principle. That is, in a low temperature environment, the mass transfer of the reaction molecules is inhibited, and the response time becomes extremely slow. In a high temperature environment, the response time becomes short.

  A variable ND filter or the like incorporated in an imaging device needs to operate without any inconvenience even in a low-temperature environment. For that purpose, it is important to heat the electrochromic element to a temperature at which it operates without delay.

  Patent Literature 1 describes that at least one of the electrodes is connected to a heating power supply and is energized in order to heat an electrochromic material layer formed on the electrodes.

JP-A-61-245143

  However, the conventional heating of the electrochromic element by energization has a problem that the driving circuit and the heating circuit configuration of the element are complicated and that relatively large power is consumed.

  On the other hand, with respect to the imaging device, due to the demand for miniaturization, the layout space of the circuit board on which the imaging element is mounted and the main circuit board on which electronic components for processing control signals and image signals are mounted have been reduced. Are arranged in a dense state. In addition, due to an increase in power consumption of the imaging device accompanying an increase in the number of pixels, the amount of heat generated by the imaging device has also increased.

  As described above, in the current imaging apparatus, the circuit board or the main circuit board on which the imaging element is mounted corresponds to a heating element.

  Therefore, the present invention improves the response performance of the electrochromic element in a low-temperature environment by efficiently transferring the heat generated in the circuit board or the imaging element of the imaging apparatus to the electrochromic element, and further improves the thermal performance of the entire imaging apparatus. It is an object of the present invention to improve the performance of an imaging device by optimizing management.

In order to achieve the above object, an imaging device according to the present invention includes:
An imaging device including an electrochromic element including an imaging element, a pair of transparent electrode substrates, and an electrochromic medium including at least one electrochromic material and a solvent disposed between the pair of transparent electrode substrates. A heat-conductive sealing member having a variable volume and sealing the electrochromic medium, and a mechanism for thermally connecting and disconnecting a heating element that is in a high temperature state during a photographing operation; It is characterized by the following.

  ADVANTAGE OF THE INVENTION According to this invention, the response performance at the time of low temperature environment of an electrochromic element is improved by efficiently transmitting the heat | fever which generate | occur | produced in the circuit board of an imaging device or an imaging element to an electrochromic element, Furthermore, the heat of the imaging apparatus whole is improved. The performance of the imaging device can be improved by optimizing the management.

FIG. 2 is a schematic cross-sectional view illustrating an embodiment of an electrochromic device used in the imaging device of the present invention. FIG. 2 is a schematic plan view illustrating an embodiment of an electrochromic device used in the imaging device of the present invention. 1 is a schematic sectional view illustrating an embodiment of an imaging device of the present invention.

  Hereinafter, preferred embodiments of the configuration of an imaging device using the electrochromic device of the present invention will be described in detail with reference to the drawings. However, the configurations, relative arrangements, and the like described in this embodiment are not intended to limit the scope of the present invention unless otherwise specified.

  An imaging device according to the present invention includes an electrochromic element having a pair of transparent electrode substrates and an electrochromic medium including at least one electrochromic material and a solvent, which is disposed between the pair of transparent electrode substrates. An encapsulating imaging device, wherein the sealing of the electrochromic medium is performed by a variable volume heat conductive sealing member, and the heat exchange between the variable volume heat conductive sealing member and a circuit board in the imaging device. It has a special connection and disconnection mechanism.

  FIG. 1 is a schematic cross-sectional view showing one embodiment of an electrochromic device 100 used in the imaging device of the present invention, and FIG. 2 is a plan view showing one embodiment of the electrochromic device 100 used in the imaging device of the present invention. It is a schematic diagram. In FIG. 1, transparent electrodes 2a and 2b are formed on glass substrates 1a and 1b, respectively. Thereby, a pair of transparent electrode substrates is formed. The pair of transparent electrode substrates are bonded together via a seal 3 containing gap control particles (not shown). At this time, an electrochromic medium 4 composed of a solvent containing at least one type of electrochromic material is provided between the pair of transparent electrode substrates. Is filled.

  Further, at least one or more power supply terminals (not shown) are provided on each of the pair of transparent electrode substrates. Each of the power supply terminals is connected to a drive power supply 7 including a drive circuit board, and a voltage pulse is applied between these terminals to drive the element.

  As a method of filling the electrochromic medium 4, a method of forming and filling a pair of electrochromic medium injection holes 5 in the glass substrates 1a and 1b, or a method of vacuum injection from a filling hole on the side surface of the element formed by a seal pattern is used. There are a method and a method of filling in a vacuum at the same time as bonding a pair of transparent electrode substrates, and any of them can be suitably used.

  Since the electrochromic device 100 in the imaging device of the present invention heats by heat transfer using the exhaust heat of a heat source such as a circuit board or an imaging device in the imaging device, these heat sources and the electrochromic device are excellent. It must be connected by a heat conductive member.

  Transparent electrodes are the only components of the electrochromic element that can be said to be good conductors of heat, but if the transparent electrode and the heat source are connected by a heat conductive member, they will interfere with the voltage application operation of the electrochromic element. .

  Therefore, in the electrochromic element 100 in the imaging apparatus of the present invention, the heat conductive member is used as the sealing member for the electrochromic medium 4, and the electrochromic medium is heated by connecting it to a heat source. .

  In addition, the volume of the electrochromic medium 4 expands by about several percent when the temperature rises. Therefore, if the electrochromic medium 4 is fixed with a non-flexible member as a sealing member, a change in outer shape occurs in which the central portion of the electrochromic element expands. . Since a change in the outer shape of the element is accompanied by an optical effect, it is preferable to use a flexible or volume-variable heat conductive portion sealing member 6 as the sealing member in the present invention.

  For example, a metal ultra-small bellows, a metal foil, or the like can be preferably used. In particular, when a metal bellows is used as a sealing member, it is preferable to inject in a state where the bellows is minimized after brazing the glass substrate using indium, indium-tin, indium-silver or the like in advance. At this time, the above brazing material can also be preferably used for sealing the injection hole of the bellows or for sealing with a metal foil.

  FIG. 3 is a schematic sectional view illustrating an embodiment of the imaging device 10 of the present invention.

  Reference numeral 9 denotes a lens unit, 10 denotes an imaging device, and an optical filter 8 using the electrochromic device of the present invention is installed in the imaging device 10 between the glass block 11 and a circuit board on which the imaging device is mounted. . Further, the heat conductive sealing member 6 of the optical filter 8 using the electrochromic element is thermally connected to or cut off from the circuit board 12 or the main circuit board 13 on which the imaging element is mounted by a mechanism 14 described later. Or be in a state of being done.

  The temperature of an optical filter 8 using an electrochromic element (hereinafter, referred to as “electrochromic optical filter 8”) is monitored by a temperature detection unit (not shown). Thus, when the electrochromic optical filter 8 is at a low temperature, thermal connection is made to the circuit board 12 and the main circuit board 13 via the cutoff mechanism 14. When the temperature of the electrochromic optical filter 8 is equal to or higher than a predetermined temperature, the thermal connection between the electrochromic optical filter 8 and the circuit board 12 or the main circuit board 13 is cut off by the cutoff mechanism 14, thereby preventing the temperature of the electrochromic element from excessively rising. Is done.

  As a specific configuration of the shutoff mechanism 14, for example, the shutoff mechanism 14 is in a state where a plurality of heat conducting members are connected, and a part of the shutoff mechanism 14 is disposed in a movable state. In addition, by moving a part of the heat conducting member by a known driving means such as a motor, the heat conducting member is connected to or disconnected from another heat conducting member. With such a configuration, the electrochromic optical filter 8 can be switched between a thermal connection state and a cutoff state with the circuit board 12 and the main circuit board 13.

  That is, the cut-off mechanism 14 corresponds to a mechanism for performing thermal connection and cut-off with the heating element that is in a high temperature state during the photographing operation of the present invention.

  As a method of using the electrochromic optical filter 8 of the present invention, an interface that performs a display that enables the electrochromic device 100 to be used after the electrochromic element 100 is heated to reach a predetermined performance is used. Can also be preferably adopted.

  Hereinafter, the electrochromic device 100 used as the electrochromic optical filter 8 of the present invention will be described in detail.

  As the glass substrates 1a and 1b, optical glass, quartz glass, white plate glass, blue plate glass, borosilicate glass, alkali-free glass, chemically strengthened glass, and the like can be used. In particular, in terms of transparency, durability, and heat resistance. Alkali-free glass can be suitably used.

  On the glass substrates 1a and 1b, in addition to the transparent electrode 2, an anti-reflection layer (not shown) for reducing the reflection on the glass substrate surface, the glass substrate-transparent electrode interface and the transparent electrode-electrochromic medium interface to improve the device transmittance. And an index matching layer can be suitably used.

  As the transparent electrode 2, a so-called transparent conductive oxide, tin-doped indium oxide (ITO), zinc oxide, gallium-doped zinc oxide (GZO), aluminum-doped zinc oxide (AZO), tin oxide, antimony-doped tin oxide (ATO) , Fluorine-doped tin oxide (FTO), niobium-doped titanium oxide (TNO), or the like.

  As the seal 3, a thermosetting resin or an ultraviolet curable resin can be used, and a suitable material is appropriately selected according to the above-described method of filling the electrochromic medium 4, that is, an element process. Further, it is preferable that the cell gap control particles for defining the distance between the pair of transparent electrode substrates are kneaded in the seal 3.

  The electrochromic medium 4 is composed of at least one kind of electrochromic material and a solvent, and may further contain other beneficial agents such as a supporting electrolyte and a thickener.

  As the electrochromic material, a compound whose visible light transmittance is changed by oxidation-reduction can be preferably used, and among them, an organic compound such as a thiophene compound, a phenazine compound, and a bipyridinium salt compound can be preferably used.

  The solvent is not particularly limited as long as it dissolves a beneficial agent such as an electrochromic material or a supporting electrolyte, but a solvent having a large polarity can be preferably used. Specifically, water, methanol, ethanol, propylene carbonate, ethylene carbonate, dimethyl sulfoxide, dimethoxyethane, γ-butyrolactone, γ-valerolactone, sulfolane, dimethylformamide, dimethoxyethane, tetrahydrofuran, acetonitrile, propionnitrile, benzonitrile, benzonitrile, Organic polar solvents such as dimethylacetamide, methylpyrrolidinone, and dioxolane are exemplified.

The supporting electrolyte is not limited as long as it is an ion dissociable salt and shows good solubility in a solvent, but an electrolyte having an electron donating property can be preferably used. Examples thereof include inorganic ion salts such as various alkali metal salts and alkaline earth metal salts, quaternary ammonium salts, and cyclic quaternary ammonium salts. Specifically, alkali metal salts of Li, Na and K such as LiClO ₄ , LiSCN, LiBF ₄ , LiAsF ₆ , LiCF ₃ SO ₃ , LiPF ₆ , LiI, NaI, NaSCN, NaClO ₄ , NaBF ₄ , NaAsF ₆ , KSCN, KCl, etc. And (CH ₃ ) ₄ NBF ₄ , (C ₂ H ₅ ) ₄ NBF ₄ , (n-C ₄ H ₉ ) ₄ NBF ₄ , (n-C ₄ H ₉ ) ₄ NPF ₆ , (C ₂ H ₅₎ And quaternary ammonium salts such as ( ₄ ) NBr, (C ₂ H ₅ ) ₄ NClO ₄ , (n-C ₄ H ₉ ) ₄ NClO _4, and cyclic quaternary ammonium salts.

  As the thickener, for example, at least one selected from the group consisting of cyanoethyl polyvinyl alcohol, cyanoethyl pullulan, and cyanoethyl cellulose can be suitably used. These include CR-V (cyanoethyl polyvinyl alcohol: softening temperature 20 to 40 ° C., dielectric constant 18.9), CR-S (cyanoethyl pullulan: softening temperature 90 to 100 ° C., dielectric constant 18.9), CR-C ( Obtained from Shin-Etsu Chemical Co., Ltd. as cyanoethyl cellulose: softening temperature of 200 ° C. or higher, dielectric constant 16), CR-M (mixture of cyanoethyl pullulan and cyanoethyl polyvinyl alcohol: softening temperature 40 to 70 ° C., dielectric constant 18.9). It is an additive that solves the conflicting problems of high viscosity and high ionic conductivity over a wide temperature range with a good balance.

  The electrochromic device 100 manufactured according to the above configuration can be set to an arbitrary optical density by voltage control or PWM control. There is a principle feature that it is slow.

  Although it depends on the configuration of the electrochromic element 100, it takes about 3 to 4 seconds for 6-step color erasing at -5 ° C, about 1 to 2 seconds at room temperature 25 ° C, and about 1 second at 60 ° C. .

  Hereinafter, an embodiment of the imaging device 10 of the present invention will be described.

  First, the electrochromic optical filter 8 using the electrochromic element 100 will be described.

  An ITO transparent electrode having a sheet resistance of 10Ω / □ was formed on a 0.7 mm thick glass substrate (EAGLE-XG manufactured by Corning), and this was used as a pair of transparent electrode substrates.

  Gap control particles (Micropearl-SP (30 μm in diameter) manufactured by Sekisui Chemical Co., Ltd.) and a thermosetting epoxy resin (Structbond HC-1850 manufactured by Mitsui Chemicals) are kneaded, and a dispenser device is used for one of the transparent electrode substrates. A seal pattern was applied by drawing and bonded to the other transparent electrode substrate on which the injection hole for the electrochromic medium 4 was formed, thereby producing an element having a gap between the electrodes of 30 μm. Here, the effective light area of the device excluding the electrochromic medium injection portion was 11 × 18 mm.

  Next, as a thermally conductive sealing member 8 having a variable volume of the electrochromic medium 4, an ultra-small bellows made of SUS was brazed to a pair of injection holes using metal indium.

  The electrochromic medium 4 was prepared by dissolving three types of anodic electrochromic materials (phenazine compounds) and three types of cathodic electrochromic materials (bipyridinium salt compounds) in a propylene carbonate solvent.

  An electrochromic medium was injected from the metal bellows hole of the device prepared above, and finally the metal bellows hole was sealed with metal indium.

  Further, a pair of lead wires were soldered to the pair of transparent electrodes 2 to produce an electrochromic optical filter 8 whose optical density was variable by applying a voltage.

  Further, a copper foil is connected to the metal bellows which is a heat conductive sealing member, and this is connected to the circuit board 12 or the main circuit board 13 on which the image pickup device is mounted via a thermal connection and cutoff mechanism 14. Then, it was incorporated into the imaging device 10.

(Evaluation)
The lens unit 9 was attached to the imaging device 10 manufactured in Example 1, and operation and actual photographing were confirmed in an environmental tester.

  First, the temperature of the environmental tester is set to −5 ° C., and the imaging apparatus is thermally connected to the electrochromic optical filter 8, the circuit board 12 on which the imaging device is mounted, and the main circuit board 13. When the temperature of the electrochromic optical filter 8 was confirmed 30 minutes after the start-up of 10 and the standard use, the temperature was about 15 ° C. At this time, the six-step decoloring time was about 2 seconds. Was. For comparison, the same evaluation was performed in a state where the thermal connection between the electrochromic optical filter 8 and the circuit board 12 and the main circuit board 13 was cut off. As a result, the temperature of the electrochromic optical filter 8 was about −5 ° C. At this time, the six-step color erasing time was about 3 to 4 seconds.

  Next, the same evaluation was performed by setting the temperature of the environmental tester to 60 ° C. At this time, in a state where the electrochromic optical filter 8 is thermally connected to the circuit board 12 and the main circuit board 13, the temperature of the electrochromic optical filter 8 after 30 minutes is about 80 ° C. The six-step color erasing time was about 0.5 to 1 second.

  On the other hand, when the thermal connection between the electrochromic optical filter 8 and the circuit board 12 and the main circuit board 13 is cut off, the temperature of the electrochromic optical filter 8 is about 60 ° C. The time was about 1 second.

  Further, for comparison, an electrochromic element in which the injection hole was sealed with a standard UV curable resin without using a metal bellows (thermally conductive sealing member 6) was manufactured, and this was mounted on the circuit board 12 and the main circuit. The same evaluation was performed by assembling the imaging device 10 with no thermal connection to the substrate 13.

  The temperature change of the electrochromic optical filter 8 was almost the same as when there was no thermal connection between the circuit board 12 and the main circuit board 13 using the metal bellows. Due to the influence of the change in the outer shape of the optical filter 8, deterioration of the captured image was confirmed in part.

  That is, in a state where the electrochromic optical filter 8 is thermally connected to the circuit board 12 and the main circuit board 13, the electrochromic optical filter 8 can be efficiently heated, and the response performance is improved in a low temperature environment. I was able to. Further, when a metal bellows is used as the heat conductive sealing member 6 having a variable volume, it is possible to buffer the volume change due to the thermal expansion of the electrochromic medium and suppress the optical influence due to the shape change. did it.

  The device of Example 2 was manufactured by the same process as in Example 1. However, a silver foil was used as the heat-conductive sealing member 8 having a variable volume, and the pair of injection holes were brazed.

(Evaluation)
The lens unit 9 was attached to the imaging device manufactured in Example 2, and the operation was confirmed in an environmental tester.

  First, the temperature of the environmental tester is set to −5 ° C., and the imaging apparatus is thermally connected to the electrochromic optical filter 8, the circuit board 12 on which the imaging device is mounted, and the main circuit board 13. When the temperature of the electrochromic optical filter 8 was confirmed 30 minutes after the start-up of 10 and the standard use was performed, the temperature was about 20 ° C., and the six-step decoloring time at this time was about 1-2. Seconds. For comparison, the same evaluation was performed in a state where the thermal connection between the electrochromic optical filter 8 and the circuit board 12 and the main circuit board 13 was cut off, and the temperature of the electrochromic optical filter 8 was about −5 ° C. The six-step color erasing time at this time was about 3 to 4 seconds.

  Next, the same evaluation was performed by setting the temperature of the environmental tester to 60 ° C.

  At this time, in a state where the electrochromic optical filter 8 is thermally connected to the circuit board 12 and the main circuit board 13, the temperature of the electrochromic optical filter 8 after about 30 minutes is about 85 ° C. The six-step color erasing time was about 0.5 seconds.

  On the other hand, when the thermal connection between the electrochromic optical filter 8 and the circuit board 12 and the main circuit board 13 is cut off, the temperature of the electrochromic optical filter 8 is about 60 ° C. Was about 1 second.

  Furthermore, the image taken at about 85 ° C. in a state where the electrochromic optical filter 8 was thermally connected to the circuit board 12 and the main circuit board 13 had a slight deterioration in image quality, and thus reached 80 ° C. By the way, when the thermal connection between the electrochromic optical filter 8 and the circuit board 12 and the main circuit board 13 was cut off, no deterioration in image quality was observed.

  That is, in a state where the electrochromic optical filter 8 is thermally connected to the circuit board 12 and the main circuit board 13, the electrochromic optical filter 8 can be efficiently heated, and the response performance is improved in a low temperature environment. I was able to. Further, when silver foil is used as the heat conductive sealing member 6 having a variable volume, although the effect of buffering the volume change due to the thermal expansion of the electrochromic medium is somewhat insufficient, the circuit board 12 and the main circuit board are not used. The mechanism for interrupting the thermal connection with the optical filter 13 can prevent an excessive temperature rise, and can suppress an optical influence due to a change in the shape of the electrochromic optical filter 8.

  As described above, according to the imaging apparatus of the present invention, the response performance of the electrochromic element in a low-temperature environment is achieved by efficiently transferring the heat generated in the circuit board and the imaging element of the imaging apparatus to the electrochromic element. And the thermal management of the entire imaging device can be optimized to improve the performance of the imaging device.

1a, 1b glass substrate, 2a, 2b transparent electrode, seal,
4 electrochromic medium,
5 injection holes for electrochromic medium,
6 thermal conductive sealing members (metal bellows),
7 drive power supply including drive circuit board,
8 An optical filter using an electrochromic element,
9 lens unit, 10 imaging device, 11 glass block,
12 a circuit board on which an image sensor is mounted, 13 a main circuit board,
14 thermal connection and disconnection mechanism between the electrochromic element and the circuit board,
100 electrochromic element

Claims (3)

An image sensor;
A pair of transparent electrode substrates,
An electrochromic medium including at least one electrochromic material and a solvent disposed between the pair of transparent electrode substrates, and an electrochromic medium including an electrochromic element,
A volume is variable, a heat conductive sealing member for sealing the electrochromic medium,
An imaging apparatus, comprising: a mechanism for thermally connecting and disconnecting a heating element that is in a high temperature state during a shooting operation.   The imaging device according to claim 1, wherein the heat conductive sealing member is a metal bellows.   The imaging device according to claim 1, wherein the heat conductive sealing member is a metal foil.