JP2016146396A - Imaging apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an imaging apparatus capable of improving an image quality of an output image.SOLUTION: An imaging apparatus according to the embodiment comprises: a filter constructed by a penetration band penetrating light, a reflection band reflecting light, and a cutoff frequency band having a penetration ratio higher than that of the reflection band and lower than that of the penetration band; and a solid state imaging apparatus that receives the light penetrated the filter. The solid state imaging apparatus comprises: a light reception part; a micro lens arranged on the light reception part; and a thin film having a first surface contacting to a surface of the micro lens and a second surface facing to the first surface. The thin film satisfies 0<T<λc/2n in the case where a wavelength of a first reflection light reflected in the surface on the micro lens and a second reflection light reflected in the second surface of the thin film is λc (λc is the wavelength in the cutoff frequency band of the filter), an index of refraction of the thin film is n, and a film thickness of the thin film is T.SELECTED DRAWING: Figure 4

Description

  Embodiments described herein relate generally to an imaging apparatus.

  Imaging devices such as small camera modules, digital cameras, and video cameras mounted on electronic devices such as mobile phones, for example, include infrared blocking filters that remove infrared rays from incident light, and image signals that receive incident light. Is mounted.

  When a conventional imaging device is used to image a high-intensity light source such as sunlight, for example, the output image may include another image (so-called ghost) different from the image of the light source in addition to the image of the light source. is there.

JP 2011-82266 A

  An object of the embodiment is to provide an imaging apparatus capable of improving the quality of an output image.

  An imaging apparatus according to an embodiment includes a filter configured by a transmission band that transmits light, a reflection band that reflects light, and a cutoff frequency band that has a transmittance higher than the reflection band and lower than the transmission band, and A solid-state imaging device that receives light transmitted through the filter. The solid-state imaging device includes a light receiving unit, a microlens provided on the light receiving unit, a first surface in contact with the surface of the microlens, and a second surface facing the first surface, Is provided. The thin film is reflected on the second surface of the thin film and the wavelength of the first reflected light having a wavelength within the cutoff frequency band of the filter among the reflected light reflected on the surface of the microlens. Of the reflected light, when the wavelength of the second reflected light having a wavelength matching the wavelength of the first reflected light is λc, the refractive index of the thin film is n, and the film thickness of the thin film is T , 0 <T <λc / 2n.

1 is a block diagram schematically illustrating an imaging apparatus according to an embodiment. It is one sectional view showing a camera module which is an example of an imaging device. It is a top view which shows typically the principal part of the pixel part of the solid-state imaging device applied to an imaging device. FIG. 4 is a cross-sectional view of a pixel portion shown along a one-dot chain line XX ′ in FIG. 3. It is a figure which shows the transmittance | permeability characteristic of the filter applied to an imaging device. It is a figure explaining a mode that the light which injected into the imaging device which concerns on a comparative example is propagated. It is a figure explaining a mode that the light which injected into the imaging device which concerns on a comparative example is propagated. It is a figure explaining a mode that the light which injected into the imaging device which concerns on a comparative example is propagated. It is a figure for demonstrating the generation | occurrence | production cause of a ghost. It is a figure which shows the light intensity distribution of diffracted light. It is sectional drawing corresponding to FIG. 4 which shows the principal part of the pixel part of the solid-state imaging device of the other form applied to an imaging device.

  Hereinafter, an imaging apparatus according to an embodiment will be described in detail with reference to the drawings.

  FIG. 1 is a block diagram schematically illustrating an imaging apparatus according to the embodiment. As illustrated in FIG. 1, the imaging device 10 includes an imaging optical system 11, a filter 12, and a solid-state imaging device 13.

  The imaging optical system 11 is a lens, for example, and is disposed in front of the solid-state imaging device 13. The imaging optical system 11 focuses incident light and forms an image on the solid-state imaging device 13.

  The filter 12 is disposed between the imaging optical system 11 and the solid-state imaging device 13. The filter 12 blocks infrared rays contained in light Lin (incident light) incident through the imaging optical system 11 and mainly transmits visible light.

  The solid-state imaging device 13 is a CMOS sensor, a CCD sensor, or the like. The solid-state imaging device 13 receives incident light Lin collected by the imaging optical system 11 through the filter 12 and photoelectrically converts the image signal S obtained by photoelectric conversion. An image is formed based on the above.

  The solid-state imaging device 13 receives incident light Lin, performs photoelectric conversion, and forms an image signal S, and a signal processing unit 15 that performs various correction processes on the image signal S obtained in the pixel unit 14. And having. The signal processing unit 15 may be a logic circuit provided in a solid-state imaging chip having the pixel unit 14, or a signal processing chip provided separately from the solid-state imaging chip having the pixel unit 14. Also good. Such a signal processing unit 15 may include a drive circuit that drives the pixel unit 14, a storage unit that stores image signals before and after correction, and the like.

  Such an imaging apparatus 10 is, for example, a small camera module mounted on an electronic device such as a digital camera, a video camera, or a mobile phone.

  FIG. 2 is a cross-sectional view illustrating a camera module which is an example of an imaging apparatus. In the camera module 10 ′ shown in FIG. 2, a solid-state imaging device 13 having a pixel portion 14 and the like is disposed on the surface of a mounting substrate 16 such as a printed circuit board. The solid-state imaging device 13 and the wiring (not shown) of the mounting substrate 16 are electrically connected by a desired means.

  Thus, on the surface of the mounting substrate 16 on which the solid-state imaging device 13 is mounted, a cylindrical lens holder 17 made of, for example, a light-shielding resin is disposed. The lens holder 17 is disposed on the surface of the mounting substrate 16 so as to cover the solid-state imaging device 13, and is fixed to the mounting substrate 16 with an adhesive or the like (not shown).

  Inside the lens holder 17, a lens barrel 18 is fitted and disposed above the solid-state imaging device 13 so as to be movable in the vertical direction with respect to the lens holder 17. The lens barrel 18 has a shape in which one end of a cylindrical light-shielding resin is closed by a top plate portion 18 t having an opening at the center, and the light is condensed on the solid-state imaging device 13 inside the lens barrel 18. A lens 11 ′ as an imaging optical system 11 (FIG. 1) is fixed.

  In addition, a screw thread is provided on the inner wall surface of the lens holder 17, and a screw groove is provided on the outer wall surface of the lens barrel 18. Accordingly, by rotating the lens barrel 18 with respect to the lens holder 17, the lens barrel 18 can be moved in the vertical direction with respect to the lens holder 17. By the movement of the lens barrel 18, the position in the vertical direction of the lens 11 'fixed inside the lens barrel 18 can be adjusted.

  In addition, in the lens holder 17, between the solid-state imaging device 13 and the lens 11 ′, the infrared rays contained in the light (incident light) incident through the lens 11 ′ is blocked to mainly transmit visible light. A filter 12 that transmits light is disposed.

  FIG. 3 is a top view schematically showing the main part of the pixel portion of the solid-state imaging device, and FIG. 4 is a cross-sectional view of the pixel portion taken along the alternate long and short dash line XX ′ in FIG. Hereinafter, the pixel unit 14 of the solid-state imaging device 13 will be described with reference to FIGS. 3 and 4.

  The pixel unit 14 of the solid-state imaging device 13 illustrated in FIG. 3 is configured by arranging a plurality of pixels 19 in a grid pattern. Each pixel 19 includes any one of a red pixel 19R, a green pixel 19G, and a blue pixel 19B, and these are arranged in a Bayer array.

  The red pixel 19R includes a red filter layer (not shown) that transmits red light, and can receive red light. Similarly, the green pixel 19G includes a green filter layer 20G (FIG. 4) that transmits green light, and can receive green light. And the blue pixel 19B contains the blue filter layer 20B (FIG. 4) which permeate | transmits blue light, and can receive blue light. Each of the red filter layer, the green filter layer 20G, and the blue filter layer 20B is provided by mixing a predetermined pigment into the transparent resin.

  As shown in FIG. 4, the red filter layer (not shown), the green filter layer 20G, and the blue filter layer 20B constitute the color filter layer 20. The color filter layer 20 is provided on the back surface side (upper surface side in the drawing) of the P-type semiconductor 21 having a substantially uniform thickness via the planarization layer 22. The semiconductor 21 is made of, for example, silicon, and the planarization layer 22 is made of, for example, a transparent silicon oxide film. The P-type semiconductor 21 may be a P-type semiconductor substrate or a P-type well layer provided on the semiconductor substrate.

  A plurality of microlenses 23 are provided in an array on the surface of the color filter layer 20. Each microlens 23 constituting the microlens array may be formed by patterning and heat treatment using a transparent resin having photosensitivity and heat flow, or a transparent resin having photosensitivity, It may be formed by patterning using a grating mask.

  On the other hand, a wiring layer 24 is provided on the surface side (lower surface side in the drawing) of the P-type semiconductor 21 so as to be in contact with the surface of the semiconductor 21. The wiring layer 24 is formed by laminating an interlayer insulating film 24i made of, for example, a silicon oxide film and a metal wiring 24m made of, for example, Cu or Al.

  As described above, the solid-state imaging device 13 according to the present embodiment is a so-called back-side illumination type (BSI type: Back Side Illumination type) solid-state imaging device that receives incident light from the back side of the semiconductor 21.

  In the BSI type solid-state imaging device 13, a plurality of N + type charge storage layers 25 are provided on the surface of the semiconductor 21, and in a region reaching the charge storage layer 25 in the depth direction from the back surface of the semiconductor 21. Are provided with a plurality of N-type light receiving layers 26. The charge storage layer 25 and the light receiving layer 26 are a pair of impurity layers. Each of the plurality of pixels 19 has such a pair of impurity layers.

  The charge storage layer 25 is electrically connected to the metal wiring 24m of the wiring layer 24. The charge accumulation layer 25 accumulates signal charges generated by photoelectric conversion in the light receiving layer 26 to form an image signal. The formed image signal is supplied to the signal processing unit 15 (FIG. 1) of the solid-state imaging device 13 through the metal wiring 24m connected to the charge storage layer 25.

  In the solid-state imaging device 13 described above, a thin film 27 made of, for example, a silicon oxide film is substantially one on the surface of the microlens array made up of a plurality of microlenses 23 arranged in an array. It is provided with various film thicknesses. The thin film 27 is a thin film having a first surface and a second surface opposite to the first surface, and is provided so that the first surface is in contact with the surface of the microlens array. The thin film 27 is a reflectance of reflected light having a desired wavelength (reflected light having a wavelength within the cutoff frequency band of the filter 12 described later in FIG. 5) among the reflected light reflected on the surface of the microlens array. It is an antireflection film having a film thickness optimized so as to be reduced. By providing such a thin film 27, the occurrence of ghost can be suppressed. Hereinafter, the effect of suppressing the ghost generation by the thin film 27 will be described in more detail.

  First, the principle of ghost generation will be described. FIG. 5 is a diagram illustrating transmittance characteristics of a filter provided in the imaging apparatus. This filter 12 is a so-called infrared blocking filter, has a transmission band that transmits incident light in the visible light region (wavelength band of 360 nm to 830 nm), and incident light in the infrared region (wavelength band of 700 nm to). A reflection band for reflecting the light. In addition, the infrared cut filter usually has a reflection band that reflects incident light also in the ultraviolet region (up to 400 nm wavelength band).

  In such a filter 12, a cut-off frequency band having a transmittance higher than the reflection band and lower than the transmission band is provided between the transmission band and the reflection band. The cut-off frequency band is composed of a first cut-off frequency band on the shorter wavelength side than the transmission band, and a second cut-off frequency band on the longer wavelength side than the transmission band. When the filter 12 is irradiated with light having a wavelength within such a cut-off frequency band, a part of the light is transmitted through the filter 12 and the other is reflected by the filter 12.

  Note that the transmittance characteristic of such a filter 12 changes according to the incident angle θ of the incident light with respect to the filter 12. When the incident angle of incident light that is incident perpendicularly to the filter 12 is θ = 0 °, the cutoff frequency band and the transmission band shift to the short wavelength side as the incident angle θ increases. Therefore, particularly when light having a wavelength in the second cutoff frequency band is incident on the filter 12, the transmittance decreases as the incident angle θ increases.

  6, 7, and 8 are diagrams for explaining how light incident on an imaging apparatus according to a comparative example is propagated. Below, with reference to FIGS. 6-8, a mode that the light which injected into the imaging device which concerns on a comparative example is propagated is demonstrated. The imaging device according to the comparative example has the same transmittance characteristics as the solid-state imaging device 113 according to the comparative example that does not have a thin film on the surface of the microlens 123 on the color filter layer 120 and the transmittance characteristics shown in FIG. The imaging device includes a filter 112 having the same.

  As shown in FIG. 6, when light L (λr) having a wavelength λr within the reflection band of the filter 112 is incident on the filter 112, the incident light L (λr) is reflected by the filter 112, and the solid-state imaging device 113. Will not reach.

  In addition, as shown in FIG. 7, when light L (λt) having a wavelength λt within the transmission band of the filter 112 is incident on the filter 112, the incident light L (λt) is transmitted through the filter 112 and is solid-state imaged. Light is received by the device 113. A part of the incident light L (λt) is reflected on the surface of the microlens 123, but the reflected light passes through the filter 112 again.

  Thus, when the incident light L (λr) or the incident light L (λt) is incident on the filter 112, the incident light L (λr) or the incident light L (λt) There is almost no multiple reflection with the device 113.

  A very small part of the incident light L (λr) passes through the filter 112 and is reflected by the microlens 123. A very small part of the incident light L (λt) reflected by the surface of the microlens 123 is reflected by the filter 112. Therefore, even when the incident light L (λr) or the incident light L (λt) is incident on the filter 112, only a part of the incident light L (λr) or the incident light L (λt) is obtained. Multiple reflections occur between the filter 112 and the solid-state imaging device 113. However, since these light intensities are extremely weak, there is little problem.

  On the other hand, as shown in FIG. 8, when light L (λc) having a wavelength λc within the cutoff frequency band of the filter 112 is incident on the filter 112, a part of the incident light L (λc) is reflected by the filter 112. However, others pass through the filter 112 and are received by the solid-state imaging device 113. Part of the incident light L (λc) that has reached the solid-state imaging device 113 is reflected on the surface of the microlens 123, and the reflected light reaches the filter 112 again. Some of the reflected light that has reached the filter 112 again passes through the filter 112, while the other is reflected by the filter 112. As described above, when the light L (λc) having the wavelength λc within the cutoff frequency band of the filter 112 is incident on the filter 112, the incident light L (λc) is multiplexed between the filter 112 and the solid-state imaging device 113. reflect. As described above, the multiple reflection of the incident light L (λc) between the filter 112 and the solid-state imaging device 113 causes a ghost.

  FIG. 9 is a diagram for explaining the cause of occurrence of a ghost. When incident light L (λc) is incident and passes through the filter 112 and reaches the microlens 123, a part of the incident light is reflected by the microlens 123. Here, since the plurality of microlenses 123 is a microlens array having a periodic structure, the reflected light reflected by the microlens array is 0th order, ± 1st order, ± 2nd order as shown in FIG. ,... Are formed. Since these diffracted lights have a wavelength of λc, they are multiple-reflected between the filter 112 and the microlens array, but when incident light L (λc) is incident on the solid-state imaging device 113 vertically, As described above, the 0th-order diffracted light is reflected in the vertical direction with respect to the solid-state imaging device 113. Accordingly, the 0th-order diffracted light is multiple-reflected within the pixel 119 that should be received, and thus does not cause ghosting.

  However, the diffracted light of ± 1st order, ± 2nd order,... Is reflected to the solid-state imaging device 113 in the directions of ± θ1, ± θ2,. Therefore, when these diffracted lights are reflected multiple times, they reach a pixel 119 ′ different from the pixel 119 that should be received, and are received by the pixel 119 ′. This causes ghosts. However, as shown in FIG. 10, the light intensity of the diffracted light becomes lower as the higher order diffracted light, and even if the incident light L is extremely high intensity light such as sunlight, the diffraction after ± 2nd order is performed. The light intensity is extremely weak. Therefore, even if the diffracted light of ± 2nd order or more is reflected multiple times, its light intensity is extremely weak, so that it is difficult to cause ghost, and the multiple reflection of ± 1st order diffracted light becomes a cause of ghost. .

  Therefore, in the solid-state imaging device 13 applied to the imaging device 10 according to the present embodiment, as shown in FIG. 4, the reflected light reflected on the surface of the microlens array is within the cutoff frequency band of the filter 12. A thin film 27 having a film thickness optimized so as to reduce the reflectance of reflected light having a wavelength λc is provided on the surface of the microlens array.

  Here, among the reflected light reflected on the surface of the microlens array, the reflected light having the wavelength λc within the cutoff frequency band of the filter 12 is used as the first reflected light, and the reflected light reflected on the second surface of the thin film 27. Of these, the reflected light having the wavelength λc that matches the wavelength λc of the first reflected light is defined as the second reflected light. At this time, the condition for synthesizing the first reflected light and the second reflected light in the same phase is expressed as in Equation 1, where T is the thickness of the thin film 27 and n is the refractive index of the thin film 27. .

T = 0 + (N × λc) / n (where N is a positive integer) (Equation 1)
Next, a condition in which the first reflected light and the second reflected light are combined by being shifted by a half wavelength is expressed as Equation 2.

T = (λc / 4n) + (N × λc) / n (where N is a positive integer) (Equation 2)
A condition for synthesizing the first reflected light and the second reflected light with a shift of one wavelength is expressed as Equation 3.

T = (λc / 2n) + (N × λc) / n (where N is a positive integer) (Equation 3)
When the film thickness T of the thin film 27 satisfies the expression 2, the first reflected light is weakened to the maximum by the second reflected light. Therefore, the thin film 27 has the film thickness T satisfying the expression 2. Is optimal. However, if the thin film 27 has a film thickness that satisfies the following expression 4, the first reflected light is weakened by the second reflected light. Accordingly, the light intensity of the ± 1st order diffracted light formed by the reflected light is smaller than the light intensity of the ± 1st order diffracted light formed by the reflected light when the thin film 27 is not provided. Therefore, the optimized film thickness of the thin film 27 means that the film thickness satisfies Expression 4.

0 <T <λc / 2n (Formula 4)
In the solid-state imaging device 13 applied to the imaging device 10 according to the present embodiment, the thin film 27 having the optimized film thickness is provided on the surface of the microlens array. Therefore, the reflectance of the reflected light having the wavelength λc within the cutoff frequency band of the filter 12 among the reflected light reflected on the surface of the microlens array can be reduced. As a result, multiple reflections of ± 1st-order diffracted light of wavelength λc between the filter 12 and the microlens array are suppressed, so that the generation of ghost can be suppressed.

  Further, as the incident light has a longer wavelength, the angle ± θ1 (FIG. 9) of the first-order diffracted light increases, and as the angle ± θ1 of the diffracted light increases, the cutoff frequency band shifts to the shorter wavelength side. Therefore, in particular, the ± first-order diffracted light having the wavelength λc2 in the second cutoff frequency band easily repeats multiple reflections between the filter 12 and the microlens array. Therefore, in particular, the thickness of the thin film 27 is optimized so that the reflectance of the reflected light having the wavelength λc2 in the second cutoff frequency band among the reflected light reflected on the surface of the microlens array can be reduced. Therefore, the generation of ghost can be more effectively suppressed. Then, the film thickness of the thin film 27 is optimized so that the reflectance of the reflected light having the center wavelength of the second cutoff frequency band among the reflected light reflected on the surface of the microlens array can be reduced. Thus, the generation of ghost can be more effectively suppressed.

  Although the generation of ghost can be effectively suppressed by optimizing the film thickness of the thin film 27 as described above, the thin film 27 is the first of the reflected lights reflected on the surface of the microlens array. You may optimize so that the reflectance of the reflected light which has the wavelength (lambda) c1 in the 1 cutoff frequency band can be reduced. Thus, even if the film thickness of the thin film 27 is optimized, the occurrence of ghost can be suppressed.

  As described above, according to the imaging device 10 according to the present embodiment, the reflected light reflected on the surface of the microlens array is reflected on the surface of the microlens array of the solid-state imaging device 13 applied to the imaging device 10. Among them, a thin film 27 having a film thickness optimized to reduce the reflectance of reflected light having a wavelength λc within the cutoff frequency band of the filter 12 is provided. As a result, multiple reflections of ± 1st-order diffracted light of wavelength λc between the filter 12 and the microlens array are suppressed, so that the generation of ghost can be suppressed. Therefore, the image quality of the image output from the imaging device 10 can be improved.

  A solid-state imaging device in which an antireflection film is provided on the surface of a microlens array is already known. However, in a generally known solid-state imaging device, the film thickness of the antireflection film is maximized with respect to light having a wavelength near 555 nm (green light) according to the maximum sensitivity of the human eye. Is set. That is, the antireflection film provided in a generally known solid-state imaging device has a film thickness that most transmits light having a wavelength near 555 nm (green light). Such an antireflection film is not optimized for light having a wavelength λc in the cutoff frequency band of the filter 12, so that ± 1st-order diffracted light having a wavelength λc in the cutoff frequency band of the filter 12 is multiplexed. Reflects and a ghost occurs.

  Although the embodiment of the present invention has been described above, this embodiment is presented as an example and is not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the spirit of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

  For example, the solid-state imaging device 13 applied to the imaging device 10 according to the above embodiment is a so-called back-illuminated solid-state imaging device. However, the present embodiment can also be applied to a surface irradiation type solid-state imaging device as shown in FIG. In other words, the pixel portion 31 of the solid-state imaging device shown in FIG. 11 is provided with a color filter layer 36 on the surface of a semiconductor 33 having a plurality of light receiving layers 32 with a wiring layer 34 and a planarizing layer 35 interposed therebetween. A microlens array in which a plurality of microlenses 37 are arranged in an array is provided on the filter layer 36. Of the reflected light reflected on the surface of the microlens array, the reflectance of the reflected light having a wavelength λc within the cutoff frequency band of the filter 12 is applied to the surface of the microlens array of the surface irradiation type solid-state imaging device. Even if the thin film 38 having a film thickness optimized so as to be reduced is provided, the occurrence of ghost can be suppressed as in the embodiment.

DESCRIPTION OF SYMBOLS 10 ... Imaging device 10 '... Camera module 11 ... Imaging optical system 11' ... Lens 12, 112 ... Filter 13, 113 ... Solid-state imaging device 14, 31 ... Pixel Part 15 ... Signal processing part 16 ... Mounting substrate 17 ... Lens holder 18 ... Lens barrel 18t ... Top plate parts 19, 119, 119 '... Pixel 19R ... Red pixel 19G ... Green pixel 19B ... Blue pixels 20, 36, 120 ... Color filter layer 20G ... Green filter layer 20B ... Blue filter layers 21, 33 ... Semiconductors 22, 35 ... Flat Microlenses 24, 34 ... Wiring layer 24i ... Interlayer insulating film 24m ... Metal wiring 25 ... Charge storage layers 26, 32 ... Light receiving layer 27, 38 ... Thin film

Claims (6)

A filter configured by a transmission band that transmits light, a reflection band that reflects light, and a cutoff frequency band that has a transmittance higher than the reflection band and lower than the transmission band;
A solid-state imaging device that receives light transmitted through the filter;
Comprising
The solid-state imaging device
A light receiver;
A microlens provided on the light receiving unit;
A thin film having a first surface in contact with the surface of the microlens and a second surface facing the first surface;
With
The thin film is reflected on the second surface of the thin film and the wavelength of the first reflected light having a wavelength within the cutoff frequency band of the filter among the reflected light reflected on the surface of the microlens. Of the reflected light, when the wavelength of the second reflected light having a wavelength matching the wavelength of the first reflected light is λc, the refractive index of the thin film is n, and the film thickness of the thin film is T , 0 <T <λc / 2n. The cutoff frequency band of the filter is configured by a first cutoff frequency band on a shorter wavelength side than the transmission band, and a second cutoff frequency band on a longer wavelength side than the transmission band,
The imaging apparatus according to claim 1, wherein the wavelengths of the first reflected light and the second reflected light are wavelengths within the second cutoff frequency band of the filter. The cutoff frequency band of the filter is configured by a first cutoff frequency band on a shorter wavelength side than the transmission band, and a second cutoff frequency band on a longer wavelength side than the transmission band,
The imaging apparatus according to claim 1, wherein the wavelengths of the first reflected light and the second reflected light are wavelengths within the first cutoff frequency band of the filter.   4. The imaging according to claim 1, wherein the thin film is a film satisfying T = (λc / 4n) + (N × λc) / n (where N is a positive integer). apparatus.   The imaging apparatus according to claim 1, wherein the thin film has a substantially uniform film thickness.   The imaging apparatus according to claim 1, further comprising an imaging optical system that focuses light on the solid-state imaging apparatus.

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