JP5144956B2 - Imaging device and imaging apparatus - Google Patents

Description

  The present invention relates to an imaging element and an imaging apparatus including the imaging element.

  Silicon, amorphous selenium, and the like are well known as materials for photoelectric conversion films used in imaging devices such as television cameras. As an image pickup apparatus using these materials as a photoelectric conversion film, a color separation prism that separates incident light into three primary color lights of red, green, and blue, and a color separation prism that is disposed in the subsequent stage of this prism and receives each color light 3 A three-plate type including a single photoelectric conversion film (imaging device) is generally used.

  By the way, such a three-plate type imaging device generally has a problem that the size is increased and the weight is increased because the above-described color separation prism and the three imaging elements are mounted. . Therefore, in order to realize a reduction in size and weight of the image pickup apparatus, it is desired to omit the color separation prism and to use a single plate type having one image pickup element. As an image pickup apparatus that meets such demands, an image pickup apparatus in which color pixels are formed by arranging red, green, and blue color filters in a Bayer arrangement on each pixel in a photoelectric conversion film plane is known ( For example, refer nonpatent literature 1).

  However, in the above-described prior art, since one of red, green, and blue is assigned to one pixel to form a color pixel, the resolution is lowered. Among them, the color components other than the color components of the color filter are absorbed when passing through the color filter, so that the light use efficiency is also lowered.

  The above-described reduction in resolution and light utilization efficiency, which is a problem in the prior art using the Bayer array, is provided with a photoelectric conversion unit in which three layers of photodiodes with controlled impurity concentration are stacked in the light incident direction. It is known that this can be improved by stacking a photoelectric conversion film having a wavelength selection function in the light incident direction (for example, see Patent Document 2).

  However, the device disclosed in Patent Document 1 inevitably has a signal readout portion formed on the same plane as the light receiving surface, and thus has an inherent difficulty in setting the aperture ratio for incident light to 100%. There is a problem that it is difficult to increase the light receiving rate.

  On the other hand, the one disclosed in Patent Document 2 is a single layer having excellent light utilization efficiency and resolution by laminating and producing photoelectric conversion films each having photosensitivity only for the three primary colors of light, red, green, and blue. A plate-type imaging device is constructed. Here, as the photoelectric conversion film, for example, an organic material is used. Many organic materials have an absorption band only in a specific wavelength range, and the molecular design is performed so that the composition has an absorption region corresponding to each of the three primary colors of red, green, and blue. A photoelectric conversion film having photosensitivity for each color light is formed.

  However, in such a configuration in which the photoelectric conversion films are laminated, it is necessary to dispose a transparent electrode for reading an electric signal between each layer (film), so that the structure is complicated and the aperture ratio is reduced. There was a problem that it was difficult to read out signals from each layer without any problems.

  Therefore, in order to solve such a problem, a method has been proposed in which signals from each layer are separated and read using the fact that the frequency characteristics of the capacitance of the film differ depending on the material (see, for example, Patent Document 3). .

  Patent Document 3 discloses that a photosensitive film forming a light receiving portion has a red photosensitive material whose electric capacity changes only by reacting with light in the red region, and an electric capacity which reacts only with light in the green region. And a blue light-sensitive material whose electric capacity changes only in response to light in the blue region. When an AC voltage is applied to each material, the electrons in the film Each material is selected so that the frequency at which the capacitance starts to decrease and the frequency at which the electric capacity begins to decrease are different from each other. At this time, the frequency characteristic of the electric capacity of the entire photosensitive film with respect to the AC voltage is as follows.

First, in the low frequency region, since the electric capacities of all the materials (three kinds of materials) can follow the frequency, the measured electric capacitance value is the sum of the electric capacities of all the materials. Next, when the frequency of the applied voltage is increased and set in the middle frequency range, the electric capacity of one of the three types of materials cannot follow the applied voltage frequency, and the electric capacity of the entire film starts to decrease. Finally, an electric capacitance value corresponding to the sum of electric capacities of the two types of materials is measured. When the frequency is further increased and set in the high frequency region, an electric capacity value corresponding to the electric capacity of one of the remaining two types of materials is measured. If the light is not irradiated capacitance value of the film in the (not irradiated with light when) C _d, since it is possible to a known predetermined value, low, medium, for each frequency region of the high, at the time of light irradiation a capacitance value C _p of the membrane, by measuring the difference in which ΔC between the capacitance value C _d of the film when not irradiated with light, so that it is possible to obtain the received light amount for the three primary colors each light.
Yuji Kiuchi, “Basics and Applications of Image Sensors”, p. 145 US Pat. No. 5,965,875 JP 2002-217474 A JP 2004-134593 A

  However, in the conventional imaging device disclosed in Patent Document 3, it is assumed that the electric capacities of three types of materials can be added. This is because the electric capacities of the three types of materials are connected in parallel. Means that The film structure of the light receiving portion that can be assumed by such a model is as shown in FIG. In other words, the light receiving unit 1 shown in FIG. 9 has a red light-sensitive material 3 that changes its electric capacity by reacting only with light in the red region between the surface electrode 2 and the back electrode 6 and light in the green region. The green light-sensitive material 4 whose electric capacity changes only by reacting and the blue light-sensitive material 5 whose electric capacity changes only by reacting with light in the blue region are sequentially arranged in a direction perpendicular to the traveling direction of incident light. It has become the composition. Such a configuration is very difficult in terms of manufacturing method, and it is impossible in principle to obtain an aperture ratio of 100% for each color.

  The present invention has been made to solve the above-described problems, and can improve the sensitivity by increasing the aperture ratio as compared with the conventional ones. Further, it is possible to reduce the size and weight and simplify the structure. An object of the present invention is to provide an image pickup device and an image pickup apparatus that can be used.

The image pickup device of the present invention includes a pair of electrodes, at least one of which has translucency, and first, second, and third wavelength bands that are sandwiched between the pair of electrodes and absorb light in the first, second, and third wavelength ranges different from each other . A photosensitive film including a second and a third material, and the first, the second, and the third material are sequentially stacked between the pair of electrodes along a traveling direction of incident light, and 1 material has a first cut-off frequency, the second material has a second cut-off frequency higher than the first cut-off frequency, and the third material is the second cut-off frequency. A third cut-off frequency higher than the cut-off frequency, and a preset frequency between zero hertz and the first cut-off frequency is f ₁ , and the first cut-off frequency to the second cut-off frequency Two frequencies set in advance between f ′ ₂ and f ₂ (f ′ ₂ <f ₂ ), two frequencies set in advance between the second cutoff frequency and the third cutoff frequency are represented as f ′ ₃ and f ₃ (f ′ ₃ <f ₃ ), and the first, when representing the impedance at the time of not irradiated with light of the second and the third material, respectively Z1, Z2 and Z3, the a at the frequency _{f 1} Z1>Z2> Z3, said frequency f _'2 and _{f 2} in the Z2>Z3> Z1 , Z3>Z2> Z1 at the frequencies f ′ ₃ and f ₃ , and one of the first, second and third materials reacts only to light in the red region. A red photosensitive material whose impedance value changes, one is a green photosensitive material whose impedance value changes only by reacting to light in the green region, and the other one is an impedance value which reacts only to light in the blue region Change A color light-sensitive material, said first, said second and said third material, respectively, the applied voltage of the frequency _{f 1, f '2, f} 2, f' 3, f 3 is the pair of electrodes If it does, it has the structure which outputs a mutually different electric current at the time of light non-irradiation and the time of light irradiation for every said frequency .

  With this configuration, the image pickup device of the present invention takes out the signal of each color light from the photosensitive film using the impedance frequency characteristics of a plurality of materials that absorb each color light, so the aperture ratio is higher than the conventional one. The sensitivity can be improved, and the size and weight can be reduced and the structure can be simplified.

In addition, due to this configuration, the imaging element of the present invention has a laminated structure in which a plurality of materials are sequentially laminated in the traveling direction of incident light, unlike conventional ones. The signal can be extracted.
Also, with this configuration, the image pickup device of the present invention can take out signals of light of three primary colors from the photosensitive film by using impedance frequency characteristics of a plurality of materials that respectively absorb light of the three primary colors.

Furthermore, the imaging device of the present invention includes a pair of electrodes , at least one of which has translucency, and a pair of electrodes that are sandwiched between the pair of electrodes and absorb light in the first, second, and third wavelength ranges different from each other. A photosensitive film including a first material, a second material, and a third material, wherein the first material, the second material, and the third material are substantially uniformly distributed between the pair of electrodes , The first material has a first cutoff frequency, the second material has a second cutoff frequency higher than the first cutoff frequency, and the third material is the second cutoff frequency. Having a third cut-off frequency higher than the cut-off frequency of the first cut-off frequency, and a preset frequency between zero hertz and the first cut-off frequency is f ₁ , and the first cut-off frequency to the second cut-off frequency f preset two frequencies were between _'2 and f _{2 (f' 2} f _2), wherein represents a preset two frequencies were between the second cut-off frequency to said third cut-off frequency f _'3 and _f 3 (f' and _{3 <f 3),} the first, when referring impedance respectively Z1, Z2 and Z3 at the time of not irradiated with light of the second and the third material, in the frequency _{f 1} Z1>Z2> is Z3, in said frequency f _'2 and _{f 2} Z2 >Z3> Z1 , Z3>Z2> Z1 at the frequencies f ′ ₃ and f ₃ , and one of the first, second and third materials reacts only to light in the red region. Red light-sensitive material whose impedance value changes, one is a green light-sensitive material whose impedance value changes only by reacting to light in the green region, and the other one is impedance which reacts only to light in the blue region Value changes That a blue light-sensitive material, said first, said second and said third material, respectively, said frequency _{f 1, f '2, f} 2, f' 3, the voltage of _{f 3} is the pair of electrodes Is applied to each of the frequencies, outputs different currents when light is not irradiated and when light is irradiated .

  Due to this configuration, the imaging device of the present invention has a single layer structure in which a plurality of materials are distributed substantially uniformly, unlike conventional ones, and a signal of each color light from the photosensitive film of this single layer structure. Can be taken out.

Also, with this configuration, the image pickup device of the present invention can take out signals of light of three primary colors from the photosensitive film by using impedance frequency characteristics of a plurality of materials that respectively absorb light of the three primary colors.

In the image pickup device of the present invention, the interval between the first cutoff frequency and the second cutoff frequency and the interval between the second cutoff frequency and the third cutoff frequency are respectively determined in advance. The first material, the second material, and the third material are set to voltages having the frequencies f ₁ , f ′ ₂ , f ₂ , f ′ ₃ , and f ₃ , respectively, provided that they are separated by a frequency interval. Instead , when voltages having the frequencies f ₁ , f ₂ , and f ₃ are applied to the pair of electrodes, the frequencies f ₁ , f ₂ , and f ₃ are different from each other when light is not irradiated and when light is irradiated. It has a configuration for outputting current.
The imaging apparatus of the present invention measures each current value in the imaging element, AC voltage applying means for applying an AC voltage of a predetermined frequency to the pair of electrodes, and the first, second, and third materials. The apparatus includes a current value measuring unit and a color image signal generating unit that generates a color image signal based on each current value.

  With this configuration, the imaging apparatus of the present invention scans the frequency and applies an AC voltage to the photosensitive film of the imaging element, thereby utilizing the impedance frequency characteristics of a plurality of materials that absorb each color light, and the photosensitive film Since each color light signal is taken out, the aperture ratio can be increased and the sensitivity can be improved as compared with the conventional one, and the size and weight can be reduced and the structure can be simplified.

  The present invention can provide an imaging apparatus that can improve the sensitivity by increasing the aperture ratio as compared with the conventional one, and that can achieve a reduction in size and weight and simplification of the structure. is there.

  Hereinafter, an embodiment of an imaging apparatus according to the present invention will be described. First, the configuration of the light receiving unit of the image sensor provided in the imaging apparatus according to the present embodiment and the signal readout algorithm of the imaging apparatus will be described.

First, the case where the light receiving portion of the image sensor has a photosensitive film made of one material layer will be described. The light receiving unit in this case has an electric capacity C and a resistance R due to polarization of the constituent molecules, and can be modeled by an equivalent circuit in which these are connected in parallel. Here, when considering a frequency range in which C and R take a constant value, the impedance (absolute value) is expressed by the equation (1), and the frequency characteristic is as shown in the conceptual diagram of FIG. It is expressed by a constant flat portion and a straight portion having an inclination of −6 dB / octave. F ₀ represents a cut-off frequency. Further, the impedance of the flat portion can be approximated by a resistance value R.

  When this material layer is irradiated with light, the capacitance increases and the resistance decreases. However, assuming that the decrease in resistance is greater than the increase in capacitance, the cutoff frequency is greater than when no light is irradiated. Therefore, as shown in the conceptual diagram of FIG. 2, the frequency characteristic of the impedance changes from X (when no light is irradiated) to Y (when the light is irradiated).

  Next, the case where the light receiving portion of the image sensor has sensitivity to a plurality of colors and has a laminated structure and a case where it has a single layer structure will be described by way of example.

  First, the light receiving portion having a laminated structure of the photosensitive film is configured as shown in FIG. The light receiving unit 10 illustrated in FIG. 3 includes a surface electrode 11 and a back electrode 15, and a material layer 12 made of a photosensitive material having sensitivity only to red light between the surface electrode 11 and the back electrode 15, A material layer 13 made of a photosensitive material sensitive only to green light and a material layer 14 made of a photosensitive material sensitive only to blue light are stacked as the photosensitive film in the direction of incident light. ing. Here, the material layers 12 to 14 have impedance values different from each other at a predetermined frequency. The order of stacking the material layers is arbitrary, and is not limited to the example shown in the figure.

  Since the surface electrode 11 is on the light incident side, the surface electrode 11 preferably has improved translucency, and is formed of, for example, indium tin oxide (ITO), indium oxide, tin oxide, or the like.

  In addition to the same material as the surface electrode 11, the back electrode 15 is made of, for example, aluminum, vanadium, gold, silver, platinum, iron, cobalt, carbon, nickel, tungsten, palladium, magnesium, calcium, tin, lead, titanium, yttrium, It is formed of a metal such as lithium, ruthenium or manganese or an alloy thereof.

  In addition, as a film thickness of the surface electrode 11, about 100-200 nm is preferable, for example, when further improving translucency, it is preferable to set it as 50-100 nm, for example.

  The material layers 12, 13, and 14 formed as a photosensitive film are made of, for example, an organic material, and have sensitivity only to one color light (wavelength band substantially corresponding to the color light) among the three primary colors of light. Any can be used. For example, acridine dyes, coumarin dyes, cyanine dyes, squarylium, oxazine dyes, xanthene dyes, azo dyes, phthalocyanines, perylene derivatives, aluminum quinolines and the like are used.

  In addition, it is more preferable to use a photorefractive material as a material for forming the material layers 12, 13 and 14, since the refractive index of the material changes due to light irradiation and the dielectric constant also changes greatly.

Examples of inorganic photorefractive materials include LiNbO ₃ , BaTiO ₃ , BGO, BSO (Bi ₁₂ SiO ₂₀ ), KTN (K (TaNb) O ₃ ), KNSBN (potassium / sodium / strontium / barium / niobate), SBN ((SrBa) Nb ₂ O ₆ ), GaAs, InP, CdTe, or the like is used.

  In addition, the photorefractive material needs to be a material in which photoconductivity and electro-optic effect coexist. In the case of an organic photorefractive material, usually a material having individual characteristics (photoconductive material and electroreflective material). A material having an optical effect) is mixed and used. As the photoconductive material, for example, polyparaphenylene vinylenes, polyfluorenes, polyvinyl carbazoles, polythiols, polythiophenes, polysilanes, liquid crystal polymers added with sensitizers such as polygermanes and fullerenes General materials are used, and examples of the material having an electro-optic effect include azobenzene dyes.

  Next, the light receiving portion having a single-layered photosensitive film is configured as shown in FIG. The light receiving unit 20 illustrated in FIG. 4 includes a surface electrode 21 and a back electrode 23, and includes a material layer 22 between the surface electrode 21 and the back electrode 23. Here, the material layer 22 includes a material part 22a that is sensitive only to red light, a material part 22b that is sensitive only to green light, and a material part 22c that is sensitive only to blue light. A single layer is formed by being uniformly distributed. Here, the material portions 22a to 22c have impedance values different from each other at a predetermined frequency.

  The material for forming the material layer 22 is the same as that in the case of the photosensitive film having the laminated structure described above, and the size of each material portion 22a, 22b, 22c is, for example, about several nm (corresponding to the size of one molecule). Formed with.

  The film formation of the material layers 12 to 14 (see FIG. 3) and 22 (see FIG. 4) is performed by a dry method represented by a vacuum evaporation method (co-evaporation method), a sputtering method, an ion plating method, or the like, or a spin method. A wet method typified by a coating method, a bar coating method, a casting method, a dipping method or the like can be used.

  Furthermore, the film thicknesses of the material layers 12 to 14 and 22 made of the photosensitive material should be set to such an extent that the voltage is not excessive and the film strength can be secured without causing a short circuit between the electrodes. For example, 50 nm to 5 μm, preferably 100 nm to 1 μm.

  Next, a calculation method for obtaining a current value corresponding to the amount of received light of each color light using the difference in the frequency response of the impedance of each material layer will be described.

If the current value that flows when an alternating voltage V = V ₀ e ^j2πft is applied between the surface electrode 11 and the back electrode 15 (or between the surface electrode 21 and the back electrode 23) is i, the light receiving unit 10 ( Alternatively, an equivalent circuit of the light receiving unit 20) is expressed as shown in FIG. In FIG. _{5, C B, C G,} C R are each material layer having sensitivity only to the light in the blue region, the material layers sensitive only to light in the green region, of the material layers sensitive only to red region Represents electric capacity. R _B , R _G , and R _R are the resistances of the material layer sensitive only to the light in the blue region, the material layer sensitive only to the light in the green region, and the resistance of the material layer sensitive only to the red region, respectively. Represent.

Capacitance _C B of each material _layer, C G, _{C R,} the resistance _{R B, R G, R R} is configured to take different values. Further, since the impedance of each material layer changes between when light is not irradiated and when light is irradiated (see FIG. 2), the impedance (absolute value) of the first material layer having sensitivity only to light in the blue region is expressed as Z. _B , where Z _G is the impedance (absolute value) of the second material layer sensitive only to light in the green region, and Z _R is the impedance (absolute value) of the third material layer sensitive only to the red region, The frequency characteristics of the impedance of each material layer are as shown in FIG. 6 when the light non-irradiation is represented by a solid line and the light irradiation is represented by a broken line.

Here, the frequencies f ₁ , f ₂ , f ′ ₂ , f ₃ , and f ′ ₃ that satisfy the following conditional expression (2) are selected, and when the light of each material layer at the respective frequencies is not irradiated, Impedance is set as in the following conditional expressions (3) to (12).

[When no light is irradiated]

[During light irradiation]

When Kirchhoff's law is applied to the circuit shown in FIG. 5 under the above conditions, the following equations (13) to (22) are obtained. The current i at frequency f ₁ when light is not irradiated is i _1D , the current i at frequency f ₂ is i _2D , the current i at frequency f ′ ₂ is i ′ _2D , and the current i at frequency f ₃ is i _3D , frequency The current i at f ′ ₃ is represented by i ′ _3D . Further, the current i at the frequency f ₁ at the time of light irradiation is i _1L , the i at the frequency f ₂ is i _2L , the current i at the frequency f ′ ₂ is i ′ _2L , the current i at the frequency f ₃ is i _3L , and the frequency f ′. it represents the current i at i _'3L in _3.

Here, the term regarding Z included in the expressions (14) to (17) and (19) to (22) is a complex number. When the electric capacity of the material layer having sensitivity to green and blue when not irradiated with light is C _GD and C _BD when not irradiated with light, and C _GL and C _BL when irradiated with light, respectively, terms relating to Z are as follows: It is expressed as

However,

From these equations, if an AC voltage V having a frequency of 0, that is, a current value at the time of light non-irradiation when a DC voltage V ₀ is applied to only one material layer, can be calculated, the difference between the two can be calculated. This corresponds to the signal current value in the material layer. That is, the signal current value in each of the first material layer sensitive only to light in the blue region, the second material layer sensitive only to the light in the green region, and the third material layer sensitive only in the red region. _Is i _{B_sig} , i _{G_sig} , i _{R_sig} , the following equation is obtained.

Here, the frequencies f ′ ₂ , f ₂ , f ′ ₃ , f ₃ are respectively f ′ ₂ >> f _{0_BD} , f ′ ₂ >> f _{0_BL} , f ₂ >> f _{0_BD} , f ₂ >> f _{0_BL} , When f ′ ₃ >> f _{0_GD} , f ′ ₃ >> f _{0_GL} , f ₃ >> f _{0_GD} , f ₃ >> f _{0_GL} are selected, the signal current values in each material layer are obtained as follows.

However,

  An imaging apparatus that implements the signal readout algorithm described above is shown in FIG. The imaging device 30 shown in FIG. 7 measures a light receiving unit 10 (see FIG. 3) that receives subject light, an AC voltage application circuit 31 that applies an AC voltage to the light receiving unit 10, and a current value of the light receiving unit 10. A current value measurement circuit 32, a signal current calculation circuit 33 that calculates a signal current based on the current value measured by the current value measurement circuit 32, and a process amplifier 34 that generates blue, green, and red color image signals. ing.

  The AC voltage application circuit 31 can scan the frequency of the AC voltage applied to the light receiving unit 10 and corresponds to the AC voltage application means of the present invention. Here, “scanning the frequency” includes not only the case of changing the frequency continuously but also the case of changing a plurality of frequencies by switching. The current value measuring circuit 32 corresponds to the current value measuring means of the present invention. The signal current calculation circuit 33 and the process amplifier 34 correspond to the color image signal generation means of the present invention. Further, the light receiving unit 20 shown in FIG. 4 may be used instead of the light receiving unit 10.

With the above configuration, the imaging apparatus 30 can reproduce the subject image as follows. First, when the frequency of the AC voltage applied to the light receiving unit 10 is changed to f ₁ , f ′ ₂ , f ₂ , f ′ ₃ , f ₃ in the AC voltage application circuit 31, when no light is irradiated. Current values i _1D , i ′ _2D , i _2D , i ′ _3D , i _3D, and current values i _1L , i ′ _2L , i _2L , i ′ _3L , i _3L at the time of light irradiation. The signal in each of the first material layer that is sensitive only to light in the blue region, the second material layer that is sensitive only to light in the green region, and the third material layer that is sensitive only to red region The current value is calculated by the signal current calculation circuit 33 based on the above equations (35) to (37). Thereafter, by generating and outputting blue, green, and red color image signals from the output signal of the signal current arithmetic circuit 33 in the process amplifier 34, it is possible to reproduce a full color image.

  As a method for calculating the signal current value, for example, the current value measured by the current value measurement circuit 32 is converted into a voltage value, and then A / D conversion is performed to obtain digital data, which is then calculated by digital signal processing. Can be considered. Therefore, the signal current calculation circuit 33 may be configured by an I_V conversion circuit, an A / D conversion circuit, and a digital signal processing circuit.

Here, as an ideal case where the above method is established, the cutoff frequency of each material layer is sufficiently separated, and the sensitivity is only to the light in the blue region at the time of light non-irradiation and light irradiation at the frequencies f ′ ₂ and f ₂ . Of the material layer having the sensitivity Z ′ _BD2 , Z ′ _BL2 , Z _BD2 , Z _BL2 and the material layer having sensitivity only to the light in the green region at the time of light irradiation at the frequencies f ′ ₃ and f ₃ . Consider a case where the impedances Z ′ _GD3 , Z ′ _GL3 , Z _GD3 , and Z _GL3 are very small and all zero. In this case, the frequency to be changed in the AC voltage application circuit 31 may be three points f ₁ , f ₂ , and f ₃ as shown in FIG. Therefore, the signal current values i _{B_sig} , i _{G_sig} , i _{R_sig} in each material layer may be set as f ′ ₂ = 0 and f ′ ₃ = 0 in the above formulas (35) to (37), and the formula (39) It is simplified as shown in (41).

Therefore, the signal current values in the respective material layers can be detected separately only from the current measurement values at the _three frequencies f ₁ , f ₂ , and f _{3 when} the light is not irradiated and when the light is irradiated.

  Note that the imaging device in the present embodiment is not limited to the one having the above-described configuration, and various other aspects can be changed. For example, in the present embodiment, the aspect in which the received image information is decomposed into the three primary color image information of blue, green, and red has been described. However, it may be configured to be decomposed into other plural color image information. Is possible.

  Further, in the present embodiment, the magnitude of the cutoff frequency is (first material) <(second material) <(third material), and the magnitude of the resistance component is (first material). Material >> (Second material)> (Third material), but the magnitude relationship is not limited to the above relationship.

  The first material is a blue light-sensitive material, the second material is a green light-sensitive material, and the third material is a red light-sensitive material. However, the correspondence between them is not limited to this.

  As described above, according to the light receiving unit 10 or 20 of the image sensor in the present embodiment, the red photosensitive material having sensitivity only to the light in the red region and the green photosensitive material having sensitivity only to the light in the green region. And a blue light-sensitive material having sensitivity only to light in the blue region, and the red light-sensitive material, the green light-sensitive material, and the blue light-sensitive material have an impedance frequency response when an AC voltage is applied. It is configured so that the characteristics are different from each other, and it is relatively easy to calculate an image electrical signal corresponding to each color intensity of blue, green, and red from the light receiving unit 10 or 20, and obtain a desired color image signal. The aperture ratio with respect to light can be made approximately 100%, and the size and weight can be reduced and the structure can be simplified.

  Moreover, according to the imaging device 30 in the present embodiment, the AC voltage application circuit 31 scans the frequency and applies an AC voltage to the light receiving unit 10 of the imaging element, and the current value measurement circuit 32 The current value is measured, the signal current calculation circuit 33 calculates a signal current based on the current value measured by the current value measurement circuit 32, and the process amplifier 34 generates a color image signal of the three primary colors of light. Therefore, the signals of the three primary colors of light can be extracted from the light receiving unit 10 by using the impedance frequency characteristics of a plurality of materials that respectively absorb blue, green, and red light. Therefore, the imaging apparatus 30 according to the present embodiment can improve the sensitivity by increasing the aperture ratio as compared with the conventional one, and can further reduce the size and weight and simplify the structure.

  As described above, the image pickup device and the image pickup apparatus according to the present invention can improve the sensitivity by increasing the aperture ratio as compared with the conventional one, and can be reduced in size and weight and simplified in structure. And is useful as an imaging device such as a TV camera or a video camera, and an imaging device including the imaging device.

The conceptual diagram which shows the frequency characteristic of an impedance in one Embodiment of the imaging device which concerns on this invention, when a light-receiving part has a photosensitive film | membrane which consists of one material layer. The conceptual diagram which shows the frequency characteristic of the impedance when changing to X (at the time of light irradiation) from X (at the time of light irradiation) in one Embodiment of the imaging device which concerns on this invention Schematic diagram showing a first configuration example of a light receiving unit in an embodiment of an imaging apparatus according to the present invention Schematic diagram showing a second configuration example of the light receiving unit in the embodiment of the imaging device according to the present invention. The figure which shows the equivalent circuit of the light-receiving part in one Embodiment of the imaging device which concerns on this invention The conceptual diagram which shows the frequency characteristic of the impedance in case one embodiment of the imaging device which concerns on this invention has a photosensitive film | membrane which a light-receiving part consists of a multiple layer material layer The block diagram which shows the structure in one Embodiment of the imaging device which concerns on this invention The conceptual diagram which shows the frequency characteristic of the impedance in one Embodiment of the imaging device which concerns on this invention when the cutoff frequency of each material layer is fully separated Schematic diagram of a light receiving unit to which a signal readout algorithm can be applied in a conventional imaging device

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Light-receiving part 11 Surface electrode 12 Material layer which consists of photosensitive material which has sensitivity only to red light 13 Material layer which consists of photosensitive material which has sensitivity only to green light 14 Material layer which consists of photosensitive material which has sensitivity only to blue light 15 Back surface Electrode 20 Light-receiving part 21 Surface electrode 22 Material layer 22a Material part sensitive only to red light 22b Material part sensitive only to green light 22c Material part sensitive only to blue light 23 Back electrode 30 Imaging device 31 AC voltage application Circuit (AC voltage application means)
32 Current value measuring circuit (current value measuring means)
33 Signal current calculation circuit (color image signal generation means)
34 process amplifier (color image signal generating means)

Claims (4)

A pair of electrodes, at least one of which is translucent,
A photosensitive film including first, second, and third materials sandwiched between the pair of electrodes and absorbing light in first, second, and third wavelength ranges different from each other;
The first, second, and third materials are sequentially stacked along the traveling direction of incident light between the pair of electrodes,
The first material has a first cutoff frequency;
The second material has a second cutoff frequency higher than the first cutoff frequency;
The third material has a third cutoff frequency higher than the second cutoff frequency;
A preset frequency between zero hertz and the first cutoff frequency is f ₁ , two preset frequencies between the first cutoff frequency and the second cutoff frequency are f ′ ₂ and f ₂ (f ′ ₂ <f ₂ ), two frequencies set in advance between the second cutoff frequency and the third cutoff frequency are f ′ ₃ and f ₃ (f ′ ₃ <f ₃ ). And when the impedance of the first, second and third materials when not irradiated with light is expressed as Z1, Z2 and Z3, respectively,
Wherein a at the frequency _{f 1} Z1>Z2> Z3,
Z2>Z3> Z1 at the frequencies f ′ ₂ and f ₂ ,
Z3>Z2> Z1 at the frequencies f ′ ₃ and f ₃ ,
Of the first, second, and third materials, one is a red photosensitive material whose impedance value changes only in response to light in the red region, and one in response only to light in the green region. A green photosensitive material whose impedance value changes, and the remaining one is a blue photosensitive material whose impedance value changes only in response to light in the blue region,
The first material, the second material, and the third material are configured so that the frequencies f ₁ , f ′ ₂ , f ₂ , f ′ ₃ , and f ₃ are applied to the pair of electrodes, respectively. Each of the imaging elements outputs different currents when light is not irradiated and when light is irradiated . A pair of electrodes, at least one of which is translucent,
A photosensitive film including first, second, and third materials sandwiched between the pair of electrodes and absorbing light in first, second, and third wavelength ranges different from each other;
The first material, the second material, and the third material are substantially uniformly distributed between the pair of electrodes,
The first material has a first cutoff frequency;
The second material has a second cutoff frequency higher than the first cutoff frequency;
The third material has a third cutoff frequency higher than the second cutoff frequency;
A preset frequency between zero hertz and the first cutoff frequency is f ₁ , two preset frequencies between the first cutoff frequency and the second cutoff frequency are f ′ ₂ and f ₂ (f ′ ₂ <f ₂ ), two frequencies set in advance between the second cutoff frequency and the third cutoff frequency are f ′ ₃ and f ₃ (f ′ ₃ <f ₃ ). And when the impedance of the first, second and third materials when not irradiated with light is expressed as Z1, Z2 and Z3, respectively,
Wherein a at the frequency _{f 1} Z1>Z2> Z3,
Z2>Z3> Z1 at the frequencies f ′ ₂ and f ₂ ,
Z3>Z2> Z1 at the frequencies f ′ ₃ and f ₃ ,
Of the first, second, and third materials, one is a red photosensitive material whose impedance value changes only in response to light in the red region, and one in response only to light in the green region. A green photosensitive material whose impedance value changes, and the remaining one is a blue photosensitive material whose impedance value changes only in response to light in the blue region,
The first material, the second material, and the third material are configured so that the frequencies f ₁ , f ′ ₂ , f ₂ , f ′ ₃ , and f ₃ are applied to the pair of electrodes, respectively. Each of the imaging elements outputs different currents when light is not irradiated and when light is irradiated . The first cutoff frequency and the second cutoff frequency, and the second cutoff frequency and the third cutoff frequency are respectively separated by a predetermined frequency interval. On condition that
Said first, said second and said third material, respectively, said frequency _f 1, f _{'2, f} 2, f' _3, wherein the frequency _f 1 in place of the voltage of the _{f 3,} f 2, _{f 3} Is applied to the pair of electrodes, different currents are output for each of the frequencies f ₁ , f ₂ , and f ₃ when light is not irradiated and when light is irradiated. The imaging device according to claim 1 or 2 . The imaging device according to any one of claims 1 to 3, AC voltage application means for applying an AC voltage having a predetermined frequency to the pair of electrodes, and the first, second, and third materials. An image pickup apparatus comprising: a current value measuring unit that measures each current value in; and a color image signal generating unit that generates a color image signal based on each current value.

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