Imaging element, manufacturing method, and electronic apparatus

The present disclosure relates to an imaging element, a manufacturing method, and an electronic apparatus which enable an image having higher image quality to be captured. In a valid pixel region in which a plurality of pixels is arranged in a matrix, a plurality of microlenses for condensing light is formed in a corresponding relation with the pixels, and in a valid pixel peripheral region which is provided so as to surround an outside of the valid pixel region, a plurality of slit type light diffraction gratings is formed such that a longitudinal direction thereof extends in a direction orthogonal to a side direction of the valid pixel region. Then, an anti-reflection film is deposited on the microlenses and the slit type light diffraction gratings. The present technology, for example, can be applied to a CMOS image sensor.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a national stage application under 35 U.S.C. 371 and claims the benefit of PCT Application No. PCT/JP2017/047264 having an international filing date of 28 Dec. 2017, which designated the United States, which PCT application claimed the benefit of Japanese Patent Application No. 2017-004580 filed 13 Jan. 2017, the entire disclosures of each of which are incorporated herein by reference.

TECHNICAL FIELD

The present disclosure relates to an imaging element, a manufacturing method, and an electronic apparatus, and more particularly to an imaging element, a manufacturing method, and an electronic apparatus which enable an image having higher image quality to be captured.

In recent years, a solid-state imaging device is used in various image inputting apparatuses such as a video camera, a digital still camera, and a facsimile. The solid-state imaging device has a pixel region in which a plurality of pixels for generating signal electric charges in accordance with a quantity of incident light is arranged in a matrix, and outputs signal electric charges generated in the respective pixels as image signals to the outside.

Incidentally, in the past solid-state imaging device, the light which is made incident to a valid pixel peripheral region provided so as to surround an outside of a valid pixel region in which pixels composing an image are arranged is reflected to turn into stray light, so that a flare, a ghost or the like is generated in the image in some cases.

Accordingly, in order to suppress the generation of a flare, a ghost or the like due to stray light, for example, PTL 1 proposes a solid-state imaging element having a configuration in which a convex body similar to an on-chip lens in the valid pixel region is provided on a surface of the valid pixel peripheral region.

CITATION LIST

Patent Literature

SUMMARY

Technical Problem

Incidentally, as described above, in the past as well, the measures to suppress the generation of a flare, a ghost or the like due to the stray light have been taken. However, the suppression effect is not sufficient, and the measures to obtain a higher suppression effect are desired. It is thus expected that a bad influence due to a flare, a ghost or the like is excluded and an image having higher image quality is captured.

The present disclosure has been made in the light of such a situation, and enables an image having higher image quality to be captured.

Solution to Problem

An imaging element according to an aspect of the present disclosure includes: a valid pixel region in which a plurality of pixels is arranged in a matrix and a plurality of microlenses for condensing light is formed in a corresponding relation with the pixels; and a valid pixel peripheral region which is provided so as to surround an outside of the valid pixel region, and in which a plurality of slit type light diffraction gratings is formed such that a longitudinal direction thereof extends in a direction orthogonal to a side direction of the valid pixel region.

A manufacturing method according to an aspect of the present disclosure includes the steps of: forming a plurality of microlenses for condensing light, in a valid pixel region in which a plurality of pixels is arranged in a matrix, in a corresponding relation with the pixels; and forming a plurality of slit type light diffraction gratings in a valid pixel peripheral region provided so as to surround an outside of the valid pixel region such that a longitudinal direction thereof extends in a direction orthogonal to a side direction of the valid pixel region.

An electronic apparatus according to an aspect of the present disclosure includes an imaging element. The imaging element includes: a valid pixel region in which a plurality of pixels is arranged in a matrix and a plurality of microlenses for condensing light is formed in a corresponding relation with the pixels; and a valid pixel peripheral region which is provided so as to surround an outside of the valid pixel region, and in which a plurality of slit type light diffraction gratings is formed such that a longitudinal direction thereof extends in a direction orthogonal to a side direction of the valid pixel region.

In one aspect of the present disclosure, a plurality of microlenses for condensing light is formed, in a valid pixel region in which a plurality of pixels is arranged in a matrix, in a corresponding relation with the pixels; and a plurality of slit type light diffraction gratings is formed in a valid pixel peripheral region provided so as to surround an outside of the valid pixel region such that a longitudinal direction thereof extends in a direction orthogonal to a side direction of the valid pixel region.

Advantageous Effect of Invention

According to one aspect of the present disclosure, an image having higher image quality can be captured.

DESCRIPTION OF EMBODIMENTS

Hereinafter, specific embodiments to which the present technology is applied will be described in detail with reference to the drawings.

<First Configuration Example of Imaging Element>

FIG. 1is a view depicting a configuration example of a first embodiment of an imaging element to which the present technology is applied. A ofFIG. 1depicts a schematic configuration when an imaging element11is planarly viewed. B ofFIG. 1depicts a cross section taken along line a-a′ and a cross section taken along line b-b′ in the imaging element11depicted in A ofFIG. 1.

As depicted in A ofFIG. 1, the imaging element11is a CMOS (Complementary Metal Oxide Semiconductor) image sensor, and includes a plurality of slit type light diffraction gratings14which is formed in a valid pixel peripheral region13provided in an outer periphery of a valid pixel region12provided substantially at a center.

The valid pixel region12is a region in which a plurality of pixels17(refer to B ofFIG. 1) is arranged in a matrix. The valid pixel region12receives light, in which an image of a subject is formed by an optical system (not depicted), for each pixel17, and outputs pixel signals for generating an image obtained by imaging the subject.

The valid pixel peripheral region13is a region provided in a circumference of the valid pixel region12, and is a region in which a peripheral circuit for driving the pixels17provided in the valid pixel region12, various kinds of wirings, and the like are formed. In addition, as depicted in the figure, a plurality of bonding pads15is formed along each of two sides (in the example of A ofFIG. 1, an upper side and a lower side) in the valid pixel peripheral region13. The bonding pads15are each an electrode through which the imaging element11is electrically connected to the outside and, for example, a bonding wire is bonded to the bonding pad15.

The slit type light diffraction gratings14are each formed such that a longitudinal direction thereof extends from one of four sides of the valid pixel region12toward the outside in a direction orthogonal to the side direction and a cross-sectional shape when viewed along the longitudinal direction is substantially a semicircular convex shape (refer to a cross section taken along line b-b′ of B ofFIG. 1). The slit type light diffraction gratings14are formed in this manner, whereby a surface shape of the valid pixel peripheral region13is formed in such a way that a normal vector to the surface is not directed toward the valid pixel region12. Therefore, for example, light made incident to the valid pixel peripheral region13shall be reflected in a direction other than the direction toward the valid pixel region12.

For example, in an upper side region16-1which contacts the upper side of the valid pixel region12and extends to left and right sides of the valid pixel peripheral region13, the slit type light diffraction gratings14are each formed in such a way that the longitudinal direction thereof extends vertically. Likewise, in a lower side region16-2which contacts the lower side of the valid pixel region12and extends to the left and right sides of the valid pixel peripheral region13, the slit type light diffraction gratings14are each formed in such a way that the longitudinal direction thereof extends vertically.

On the other hand, in a left side region16-3which contacts a left side of the valid pixel region12and extends between the upper side region16-1and the lower side region16-2of the valid pixel peripheral region13, the slit type light diffraction gratings14are each formed in such a way that the longitudinal direction thereof extends in the left and right direction. Likewise, in a right side region16-4which contacts a right side of the valid pixel region12and extends between the upper side region16-1and the lower side region16-2of the valid pixel peripheral region13, the slit type light diffraction gratings14are each formed in such a way that the longitudinal direction thereof extends in the left and right direction.

Here, a formation pitch as an interval between the slit type light diffraction gratings14formed adjacent to each other is by no means limited to a specific interval. For example, in a process (a fifth process ofFIG. 4which will be described later) for forming the slit type light diffraction gratings14, the formation pitch of the slit type light diffraction gratings14is limited by an exposure wavelength used by an aligner (semiconductor manufacturing device) which is used in patterning of a positive photoresist. Specifically, the formation pitch of the slit type light diffraction gratings14is formed at 0.35 μm or more in the case where i-ray is used for the exposure wavelength, and is formed at 0.24 μm or more in the case where a KrF excimer laser is used for the exposure wavelength.

For example,FIG. 2depicts reflected diffraction light which is generated in accordance with the formation pitch of the slit type light diffraction gratings14when the light made incident to one of the slit type light diffraction gratings14is reflected by the slit type light diffraction grating14. For example, with respect to a relation among the formation pitch d of the slit type light diffraction gratings14, an incident light wavelength λ, a diffraction angle θ, and a diffraction order m (0, ±1, ±2, ±3, . . . ), an equation depicted inFIG. 2holds.

In addition, the imaging element11, as depicted in B ofFIG. 1, is configured by laminating a semiconductor substrate21, a first flattening film22, a color filter layer23, a microlens layer24, and an anti-reflection film25.

The semiconductor substrate21, for example, is a wafer obtained by thinly slicing a semiconductor including silicon or the like. A plurality of photodiodes31is formed in the semiconductor substrate21so as to correspond to the plurality of pixels17provided in the valid pixel region12.

In addition, an inter-pixel light-shielding film32and wirings33and34are deposited on the surface of the semiconductor substrate21. The inter-pixel light-shielding film32is arranged between the pixels17in the valid pixel region12, and performs light-shielding for preventing color mixing between the adjacent pixels17. The wirings33and34are used in a peripheral circuit provided in the valid pixel peripheral region13.

The first flattening film22buries stepped portions at end portions of the inter-pixel light-shielding film32and the wirings33and34to flatten the surface.

In the color filter layer23, a filter35transmitting light of a corresponding color is formed for each pixel17in the valid pixel region12and a light absorbing film36is formed in the valid pixel peripheral region13. For example, for the filter35formed for each pixel17in the valid pixel region12, red, green, and blue are used as primary colors, and yellow, cyan, and magenta are used as complementary colors. Then, the pixels17each receive the light transmitted through the corresponding filter35.

In addition, for example, a material obtained by internally adding a black-based pigment including carbon black, a black titanium oxide, an iron oxide (magnetite type triiron tetraoxide), a composite oxide of copper and chromium, a composite oxide of copper, chromium, and zinc, or the like is used for the light absorbing film36which is formed over a surface of the valid pixel peripheral region13. It should be noted that the light absorbing film36may use the pigment of at least any one color of the pigments of primary colors such as red, green, and blue, and the pigments of complementary colors such as yellow, cyan, and magenta similarly to the case of the filter35, and can be formed concurrently with the filter35having the color of interest. Alternatively, the light absorbing film36may be formed in such a way that the filters35having the respective colors are extended to the valid pixel peripheral region13in an arrangement similar to that in the valid pixel region12.

A material having a refractive index of approximately 1.5 to 1.6 is used for the microlens layer24. Then, a plurality of microlenses37for condensing light irradiated to the respective pixels17is formed in a corresponding relation with the pixels17in the valid pixel region12of the microlens layer24. The microlens37is provided for each pixel17in this manner, resulting in that an effective area which is effective for reception of light by the pixel17can be enlarged and the sensitivity characteristics of the imaging element11can be enhanced.

Moreover, the slit type light diffraction gratings14as described above are formed in the valid pixel peripheral region13of the microlens layer24.

The anti-reflection film25is a film including a material having a lower refractive index than that of the microlens layer24and is deposited over the whole surface of the microlenses37and the slit type light diffraction gratings14in the microlens layer24. It should be noted that the anti-reflection film25has an opening which is opened at a portion at which the bonding pad16is provided for bonding the bonding wire to the bonding pad16.

As described above, in the imaging element11, a plurality of slit type light diffraction gratings14is formed in the valid pixel peripheral region13in such a way that the longitudinal direction thereof extends in the direction orthogonal to the side direction of the valid pixel region12. Therefore, in the imaging element11, the light made incident to the valid pixel peripheral region13shall be reflected toward a direction orthogonal to the longitudinal direction of the plurality of slit type light diffraction gratings14. Thus, such reflected light as to be directed toward the valid pixel region12can be reduced. As a result, in the imaging element11, a flare, a ghost or the like due to such stray light as to be reflected toward the valid pixel region12can be effectively suppressed, and an image having high image quality free from the flare, the ghost or the like can be captured.

<Method of Manufacturing Imaging Element>

A method of manufacturing the imaging element11will be described with reference toFIG. 3toFIG. 5.

First, in a first process, as depicted in an upper stage ofFIG. 3, the inter-pixel light-shielding film32and the wirings33and34are formed on the surface of the semiconductor substrate21in which the plurality of photodiodes31is formed.

In a second process, as depicted in a middle stage ofFIG. 3, the first flattening film22is deposited so as to bury the stepped portions at the end portions of the inter-pixel light-shielding film32and the wirings33and34on the surface of the semiconductor substrate21for flattening. For example, after a material such as an acrylic thermosetting resin is spin-coated, the material is subjected to a heat treatment to be cured, thereby forming the first flattening film22.

In a third process, as depicted in a lower stage ofFIG. 3, the color filter layer23is formed so as to be laminated on the first flattening film22. The color filter layer23is formed by the filter35of the corresponding color for each photodiode31in the valid pixel region12, and is formed by the light absorbing film36including the material to which the pigment such as the black-based colors, the primary colors, or the complementary colors as described above is internally added in the valid pixel peripheral region13.

Subsequently, in a fourth process, as depicted in an upper stage ofFIG. 4, a microlens material film41is formed so as to be laminated on the color filter layer23. For example, after a material such as a polystyrene or acrylic material, or a material including a copolymeric thermosetting resin of these materials is spin-coated, the material is subjected to a heat treatment to be cured, thereby forming the microlens material film41.

In a fifth process, as depicted in a middle stage ofFIG. 4, positive photoresist patterns42and43are formed so as to be laminated on the microlens material film41. For example, in the valid pixel region12, the positive photoresist pattern42is formed so as to correspond to portions at which the photodiodes31are arranged. On the other hand, in the valid pixel peripheral region13, the photoresist pattern43is formed at intervals in accordance with the formation pitch of the slit type light diffraction gratings14with a longitudinal direction thereof following the slit type light diffraction gratings14. It should be noted that, for example, after a resist material having photosensitivity is spin-coated, the resist is pre-baked and is exposed in accordance with the respective patterns, and then is subjected to a developing process, thereby forming the photoresist patterns42and43.

In a sixth process, as depicted in a lower stage ofFIG. 4, a process is performed such that a microlens base material pattern44is formed from the photoresist pattern42, and a slit base material pattern45is formed from the photoresist pattern43. For example, heat reflow by a heat treatment at a temperature equal to or higher than a heat softening point of each of the photoresist patterns42and43is performed for the photoresist patterns42and43, thereby forming the microlens base material pattern44according to the shape of the microlens37and the slit base material pattern45according to the shape of the slit type light diffraction grating14.

Subsequently, in a seventh process, as depicted in an upper stage ofFIG. 5, in the valid pixel region12, the microlens37is arranged for each pixel17, and in the valid pixel peripheral region13, the microlens layer24is formed in which the slit type light diffraction gratings14are arranged. For example, together with the microlens base material pattern44and the slit base material pattern45, the microlens material film41formed as the base of the patterns44and45is subjected to dry etching processing using gas such as fluorocarbon gas. As a result, the microlens base material pattern44is transferred by an etching method such that the effective area of the microlens is enlarged, thereby forming the microlens37in the microlens layer24. At the same time, the slit base material pattern45is transferred by the etching method, thereby forming the slit type light diffraction grating14in the microlens layer24.

In an eighth process, as depicted in a lower stage ofFIG. 5, the anti-reflection film25is deposited over the entire surface of the microlens layer24. A silicon oxide film, for example, having a refractive index of approximately 1.45 is used for the anti-reflection film25, and heat of approximately 180° C. to 220° C. is used for the deposition of the silicon oxide film in consideration of heat resistance properties of the first flattening film22, the color filter layer23, the microlens layer24, and the like.

By performing the processes as described above, the imaging element11can be manufactured. In this case, in the imaging element11, the plurality of microlenses37is formed so as to correspond to the respective pixels17in the valid pixel region12, the plurality of slit type light diffraction gratings14is formed in the valid pixel peripheral region13, and the anti-reflection film25is deposited on the microlenses37and the slit type light diffraction gratings14. As a result, as described above, it is possible to manufacture the imaging element11having the higher quality in which the light reflected in the valid pixel peripheral region13can be prevented from being directed toward the valid pixel region12and the generation of a flare, a ghost, or the like can be suppressed.

Here, various image inputting apparatuses each using the imaging element11have therein respective optical systems. In this case, the light made incident to the image inputting apparatus is guided to the valid pixel region12of the imaging element11via an optical path including a lens, a prism, a mirror and the like of the optical system. For this reason, the formation pitch of the slit type light diffraction gratings14needs to be adaptively changed depending on the optical systems of the various image inputting apparatuses. Moreover, the slit type light diffraction gratings14may be formed at different formation pitches in one imaging element11.

FIG. 6depicts modified changes of the slit type light diffraction gratings14.

For example, in an imaging element11A depicted in A ofFIG. 6, a formation pitch of the slit type light diffraction gratings14formed in the upper side region16-1and the lower side region16-2, and a formation pitch of the slit type light diffraction gratings14formed in a left side region16-3A and a right side region16-4A are different in interval from each other.

In addition, in an imaging element11B depicted in B ofFIG. 6, the slit type light diffraction gratings14are formed only in the upper side region16-1and the lower side region16-2. On the other hand, no slit type light diffraction grating14is formed in the left side region16-3and the right side region16-4, and thus the left side region16-3and the right side region16-4are in a flat state.

In this way, in the imaging element11, the slit type light diffraction gratings14which are optimal for suppression of the incidence of the stray light to the valid pixel region12can be formed depending on the optical system of the image inputting apparatus to be used.

<Second and Third Configuration Examples of Imaging Element>

Second and third embodiments, of the imaging element, to which the present technology is applied will now be described with reference toFIG. 7. It should be noted that in imaging elements11C and11D depicted inFIG. 7, the constituent elements common to those of the imaging element11ofFIG. 1are assigned the same reference signs, and a detailed description thereof is omitted.

A ofFIG. 7depicts a cross section taken along line a-a′ and a cross section taken along line b-b′ in the imaging element11C similarly to the case of B ofFIG. 1.

For example, in the image element11ofFIG. 1, as described above, the microlenses37and the slit type light diffraction gratings14are formed by using the dry etching method. On the other hand, the configuration of the imaging element11C is different from the configuration of the imaging element11in that microlenses52and slit type light diffraction gratings14C are formed by using heat reflow (heat melt reflow) method.

That is, in the imaging element11C, the semiconductor substrate21, the first flattening film22, the color filter layer23, and the anti-reflection film25are configured similarly to the case of the imaging element11ofFIG. 1. On the other hand, the configuration of the imaging element11C is different from the configuration of the imaging element11of FIG.1in that a second flattening film51is deposited on the color filter layer23, and the microlenses52and the slit type light diffraction gratings14C are formed so as to be laminated on the second flattening film51.

For example, after bleaching exposure is performed for positive photosensitive resins each of which is formed into a pattern by performing exposure and development process by utilizing a known photolithography method to attenuate light absorption of a visible light short wavelength region of a photosensitive material in the photosensitive resins, the heat reflow is performed to form the microlenses52and the slit type light diffraction gratings14C. Thereafter, the anti-reflection film25having a lower refractive index than those of the positive photosensitive resins is deposited. Here, in the photosensitive material in the positive photosensitive resins, light absorption occurs on a short wavelength side of the visible light region. Thus, before the heat reflow is performed, ultraviolet exposure is performed to decompose the photosensitive material to attenuate the light absorption, thereby enabling the higher image quality to be achieved. For example, a material such as a polystyrene or acrylic material, or a material including a copolymeric thermosetting resin of these materials can be used for the microlenses52and the slit type light diffraction gratings14C. In this case, the refractive index of the microlenses52and the refractive index of the slit type light diffraction gratings14C are approximately 1.5 to 1.6, and a silicon oxide film having the refractive index of approximately 1.45 is used for the anti-reflection film25.

B ofFIG. 7depicts a cross section taken along line a-a′ and a cross section taken along line b-b′ in an imaging element11D similarly to the case of B ofFIG. 1.

In the imaging element11D depicted in B ofFIG. 7, the semiconductor substrate21, the first flattening film22, the color filter layer23, and the anti-reflection film25are configured similarly to the case of the imaging element11ofFIG. 1. In addition, the imaging element11D is similar to the imaging element11ofFIG. 1also in that the microlenses37are formed in the microlens layer24in the valid pixel region12.

On the other hand, the configuration of the imaging element11D is different from the configuration of the imaging element11ofFIG. 1in that, in the valid pixel peripheral region13, slit type light diffraction gratings14D formed so as to be laminated on the second flattening film51include a material different from the material of the microlens layer24.

For example, a material obtained by internally adding a black-based pigment including carbon black, a black titanium oxide, an iron oxide (magnetite type triiron tetraoxide), a composite oxide of copper and chromium, a composite oxide of copper, chromium, and zinc, or the like can be used for the slit type light diffraction gratings14D. The material having a light absorption property is used for the slit type light diffraction gratings14D in this manner, resulting in that a quantity of stray light entering the inside of the valid pixel peripheral region13can be reduced, and accordingly the reflected light from a peripheral circuit, a wiring metal (the wirings33and34) and the like shall be reduced.

Therefore, in the imaging element11D, along with the reduction of the reflected light in the valid pixel peripheral region13, re-reflected light from the electronic apparatus optical system can be reduced. Thus, a flare or a ghost which is generated due to the incidence of the re-reflected light to the valid pixel region12shall be reduced. As a result, the deterioration of the image quality of the imaging element11D can be suppressed.

<Configuration Example of Imaging Device Utilizing Photolysis Prism>

FIG. 8depicts a schematic configuration example of an imaging device utilizing a photolysis prism.

As depicted inFIG. 8, an imaging device61includes an objective62, a photolysis prism63, and imaging elements11-1to11-3.

The objective62condenses incident light made incident to the imaging device61to form an image of a subject on light receiving surfaces of the imaging elements11-1to11-3.

The photolysis prism63is configured so as to transmit only light of a specific wavelength range and reflect light other than the light of the specific wavelength range, and, for example, splits the incident light into red light, green light, and blue light. For example, the photolysis prism63transmits light of a green wavelength range to cause the light to be received by the imaging element11-2, reflects light of a red wavelength range to cause the light to be received by the imaging element11-1, and reflects light of a blue wavelength range to cause the light to be received by the imaging element11-3. It should be noted that each of the imaging elements11-1to11-3is not provided with the filter35for each pixel17as described above, and all the pixels17receive the light of the corresponding wavelength ranges.

In the imaging device61configured in this manner, in the case where in the valid pixel peripheral region13of each of the imaging elements11-1to11-3, light is reflected toward the valid pixel region12, it is assumed that the light of interest is re-reflected within the photolysis prism63and made incident as stray light to the valid pixel region12of the imaging element11. Heretofore, such stray light turns into a flare, a ghost, or the like to cause deterioration of the image quality.

On the other hand, the imaging elements11-1to11-3have the configuration in which in the valid pixel peripheral region13, the reflection of such light as to be directed toward the valid pixel region12is suppressed. Therefore, it is avoided that the stray light via the photolysis prism63is made incident to the valid pixel region12. As a result, the imaging elements11-1to11-3can capture an image having high image quality free from a flare, a ghost or the like.

<Configuration Example of Imaging Device>

It should be noted that the imaging element11as described above, for example, can be applied to various kinds of electronic apparatuses such as an imaging system such as a digital still camera or a digital video camera, a mobile phone including an imaging function, or other apparatuses including an imaging function.

FIG. 9is a block diagram depicting a configuration example of an imaging device mounted to an electronic apparatus.

As depicted inFIG. 9, an imaging device101includes an optical system102, an imaging element103, a signal processing circuit104, a monitor105, and a memory106, and can capture still images and moving images.

The optical system102includes one or a plurality of lenses, and guides image light (incident light) from a subject to the imaging element103to cause image formation on a light receiving surface (sensor part) of the imaging element103.

The imaging element11described above is applied as the imaging element103. Electrons are accumulated in the imaging element103for a given period of time in accordance with an image formed on the light receiving surface via the optical system102. Then, a signal according to the electrons accumulated in the imaging element103is supplied to the signal processing circuit104.

The signal processing circuit104executes various kinds of signal processing for a pixel signal outputted from the imaging element103. An image (image data) obtained by the signal processing circuit104executing the signal processing is supplied to the monitor105to be displayed, or supplied to the memory106to be stored (recorded).

In the imaging device101configured in this manner, the imaging element11as described above is applied, thereby, for example, enabling an image having higher image quality to be captured.

<Use Examples of Image Sensor>

FIG. 10is a view depicting examples of use in which the image sensor described above is used.

The image sensor described above, for example, as will be described below, can be used in various cases of sensing light such as visible light, infrared light, ultraviolet light, and X-rays.A device, which captures an image for use in appreciation, such as a digital camera or a portable apparatus with a camera function.A device, for use in traffic, such as a vehicle-mounted sensor which photographs a front side, a rear side, a periphery, an inside or the like of an automobile for safe driving in automatic stop or the like, recognition of a state of a driver, or the like, a monitoring camera which monitors a travelling vehicle and a road, or a distance measuring sensor which measures a distance between vehiclesA device, for use in consumer electronics such as a TV, a refrigerator, or an air conditioner, which images a gesture of a user to perform an apparatus operation according to the gestureA device, for use in medical care or health care, such as an endoscope, or a device which photographs a blood vessel by receiving infrared lightA device, for use in security, such as a monitoring camera for security applications, or a camera for person authentication applicationsA device, for use in beauty, such as a skin measuring instrument which photographs a skin, or a microscope which photographs a scalpA device, for use in sport, such as an action camera or a wearable camera for sport applicationsA device, for use in agriculture, such as a camera which monitors a state of a field or crops

<Example of Application to Endoscopic Surgery System>

The technology according to the present disclosure (present technology) can be applied to various products. For example, the technology according to the present disclosure may be applied to an endoscopic surgery system.

FIG. 12is a block diagram depicting an example of a functional configuration of the camera head11102and the CCU11201depicted inFIG. 11.

The example of the endoscopic surgery system to which the technology according to the present disclosure can be applied has been described so far. The technology according to the present disclosure can be applied to the endoscope11100, (the image pickup unit11402of) the camera head11102, (the image processing unit11412of) the CCU11201, and the like among the constituent elements described above. Specifically, for example, the imaging element11ofFIG. 1can be applied to the image pickup unit11402. Since the technology according to the present disclosure is applied to the image pickup unit11402, resulting in that an image of a surgical region having higher image quality can be obtained, the surgeon can reliably confirm the surgical region.

<Example of Application to In-Vivo Information Acquisition System>

The technology according to the present disclosure (present technology) can be applied to various products. For example, the technology according to the present disclosure may be applied to an endoscopic surgery system.

FIG. 13is a block diagram depicting an example of a schematic configuration of an in-vivo information acquisition system of a patient using a capsule type endoscope, to which the technology according to an embodiment of the present disclosure (present technology) can be applied.

The in-vivo information acquisition system10001includes a capsule type endoscope10100and an external controlling apparatus10200.

The capsule type endoscope10100is swallowed by a patient at the time of inspection. The capsule type endoscope10100has an image pickup function and a wireless communication function and successively picks up an image of the inside of an organ such as the stomach or an intestine (hereinafter referred to as in-vivo image) at predetermined intervals while it moves inside of the organ by peristaltic motion for a period of time until it is naturally discharged from the patient. Then, the capsule type endoscope10100successively transmits information of the in-vivo image to the external controlling apparatus10200outside the body by wireless transmission.

The external controlling apparatus10200integrally controls operation of the in-vivo information acquisition system10001. Further, the external controlling apparatus10200receives information of an in-vivo image transmitted thereto from the capsule type endoscope10100and generates image data for displaying the in-vivo image on a display apparatus (not depicted) on the basis of the received information of the in-vivo image.

In the in-vivo information acquisition system10001, an in-vivo image imaged a state of the inside of the body of a patient can be acquired at any time in this manner for a period of time until the capsule type endoscope10100is discharged after it is swallowed.

A configuration and functions of the capsule type endoscope10100and the external controlling apparatus10200are described in more detail below.

The capsule type endoscope10100includes a housing10101of the capsule type, in which a light source unit10111, an image pickup unit10112, an image processing unit10113, a wireless communication unit10114, a power feeding unit10115, a power supply unit10116and a control unit10117are accommodated.

The light source unit10111includes a light source such as, for example, a light emitting diode (LED) and irradiates light on an image pickup field-of-view of the image pickup unit10112.

The image pickup unit10112includes an image pickup element and an optical system including a plurality of lenses provided at a preceding stage to the image pickup element. Reflected light (hereinafter referred to as observation light) of light irradiated on a body tissue which is an observation target is condensed by the optical system and introduced into the image pickup element. In the image pickup unit10112, the incident observation light is photoelectrically converted by the image pickup element, by which an image signal corresponding to the observation light is generated. The image signal generated by the image pickup unit10112is provided to the image processing unit10113.

The image processing unit10113includes a processor such as a central processing unit (CPU) or a graphics processing unit (GPU) and performs various signal processes for an image signal generated by the image pickup unit10112. The image processing unit10113provides the image signal for which the signal processes have been performed thereby as RAW data to the wireless communication unit10114.

The wireless communication unit10114performs a predetermined process such as a modulation process for the image signal for which the signal processes have been performed by the image processing unit10113and transmits the resulting image signal to the external controlling apparatus10200through an antenna10114A. Further, the wireless communication unit10114receives a control signal relating to driving control of the capsule type endoscope10100from the external controlling apparatus10200through the antenna10114A. The wireless communication unit10114provides the control signal received from the external controlling apparatus10200to the control unit10117.

The power feeding unit10115includes an antenna coil for power reception, a power regeneration circuit for regenerating electric power from current generated in the antenna coil, a voltage booster circuit and so forth. The power feeding unit10115generates electric power using the principle of non-contact charging.

The power supply unit10116includes a secondary battery and stores electric power generated by the power feeding unit10115. InFIG. 13, in order to avoid complicated illustration, an arrow mark indicative of a supply destination of electric power from the power supply unit10116and so forth are omitted. However, electric power stored in the power supply unit10116is supplied to and can be used to drive the light source unit10111, the image pickup unit10112, the image processing unit10113, the wireless communication unit10114and the control unit10117.

The control unit10117includes a processor such as a CPU and suitably controls driving of the light source unit10111, the image pickup unit10112, the image processing unit10113, the wireless communication unit10114and the power feeding unit10115in accordance with a control signal transmitted thereto from the external controlling apparatus10200.

The external controlling apparatus10200includes a processor such as a CPU or a GPU, a microcomputer, a control board or the like in which a processor and a storage element such as a memory are mixedly incorporated. The external controlling apparatus10200transmits a control signal to the control unit10117of the capsule type endoscope10100through an antenna10200A to control operation of the capsule type endoscope10100. In the capsule type endoscope10100, an irradiation condition of light upon an observation target of the light source unit10111can be changed, for example, in accordance with a control signal from the external controlling apparatus10200. Further, an image pickup condition (for example, a frame rate, an exposure value or the like of the image pickup unit10112) can be changed in accordance with a control signal from the external controlling apparatus10200. Further, the substance of processing by the image processing unit10113or a condition for transmitting an image signal from the wireless communication unit10114(for example, a transmission interval, a transmission image number or the like) may be changed in accordance with a control signal from the external controlling apparatus10200.

Further, the external controlling apparatus10200performs various image processes for an image signal transmitted thereto from the capsule type endoscope10100to generate image data for displaying a picked up in-vivo image on the display apparatus. As the image processes, various signal processes can be performed such as, for example, a development process (demosaic process), an image quality improving process (bandwidth enhancement process, a super-resolution process, a noise reduction (NR) process and/or image stabilization process) and/or an enlargement process (electronic zooming process). The external controlling apparatus10200controls driving of the display apparatus to cause the display apparatus to display a picked up in-vivo image on the basis of generated image data. Alternatively, the external controlling apparatus10200may also control a recording apparatus (not depicted) to record generated image data or control a printing apparatus (not depicted) to output generated image data by printing.

The example of the in-vivo information acquisition system to which the technology according to the present disclosure can be applied has been described so far. The technology according to the present disclosure can be applied to the image pickup unit10112among the constituent elements described above. Specifically, for example, the imaging element11ofFIG. 1can be applied to the image pickup unit10112. Since the technology according to the present disclosure is applied to the image pickup unit10112, resulting in that an image of a surgical region having higher image quality can be obtained, the accuracy of the inspection can be enhanced.

<Example of Application to Mobile Body>

The technology according to the present disclosure (present technology) can be applied to various products. For example, the technology according to the present disclosure may also be realized as a device mounted to any kind of mobile body such as an automobile, an electric automobile, a hybrid electric automobile, a motorcycle, a bicycle, a personal mobility, an airplane, a drone, a ship, or a robot.

FIG. 15is a diagram depicting an example of the installation position of the imaging section12031.

The example of the vehicle control system to which the technology according to the present disclosure can be applied has been described so far. The technology according to the present disclosure, for example, can be applied to the imaging section12031or the like among the constituent elements described above. Specifically, for example, the imaging element11ofFIG. 1can be applied to the imaging section12031. The technology according to the present disclosure is applied to the imaging section12031, resulting in that, for example, the outside-vehicle information can be acquired with higher image quality, and the enhancement of the safety of the automatic driving or the like can be realized.

<Examples of Combination of Configurations>

It should be noted that the present technology can also adopt the following configurations.

a valid pixel region in which a plurality of pixels is arranged in a matrix and a plurality of microlenses for condensing light is formed in a corresponding relation with the pixels; and

a valid pixel peripheral region which is provided so as to surround an outside of the valid pixel region, and in which a plurality of slit type light diffraction gratings is formed such that a longitudinal direction thereof extends in a direction orthogonal to a side direction of the valid pixel region.

The imaging element according to (1) described above, in which an anti-reflection film is deposited on the slit type light diffraction gratings and the microlenses.

The imaging element according to (1) or (2) described above, in which the slit type light diffraction gratings in the valid pixel peripheral region are formed in a same process as a process for forming the microlenses in the valid pixel region.

The imaging element according to any one of (1) to (3) described above, in which the slit type light diffraction gratings in the valid pixel peripheral region and the microlenses in the valid pixel region are formed by using an etching method.

The imaging element according to any one of (1) to (3) described above, in which the slit type light diffraction gratings in the valid pixel peripheral region and the microlenses in the valid pixel region are formed by using a heat reflow method.

The imaging element according to any one of (1) to (5) described above, in which the slit type light diffraction gratings in the valid pixel peripheral region include a material different from a material of the microlenses in the valid pixel region.

A manufacturing method including the steps of:

forming a plurality of microlenses for condensing light, in a valid pixel region in which a plurality of pixels is arranged in a matrix, in a corresponding relation with the pixels; and

forming a plurality of slit type light diffraction gratings in a valid pixel peripheral region provided so as to surround an outside of the valid pixel region such that a longitudinal direction thereof extends in a direction orthogonal to a side direction of the valid pixel region.

An electronic apparatus including:

an imaging element includinga valid pixel region in which a plurality of pixels is arranged in a matrix and a plurality of microlenses for condensing light is formed in a corresponding relation with the pixels, anda valid pixel peripheral region which is provided so as to surround an outside of the valid pixel region, and in which a plurality of slit type light diffraction gratings is formed such that a longitudinal direction thereof extends in a direction orthogonal to a side direction of the valid pixel region.

It should be noted that the embodiments are by no means limited to the embodiments described above, and various changes can be made without departing from the subject matter of the present disclosure.

REFERENCE SIGNS LIST