Light detection device

Abstract

The present disclosure relates to a light detection device that makes it possible to suppress degradation of the image quality of an image that is captured by a lensless camera. In the present disclosure, the image quality of an image that is captured by a lensless camera is increased by reducing the principal curvature of an on-chip lens, and thus widening a high sensitivity range close to an angular field of view of 0 degrees. The present disclosure is applicable to a lensless camera.

Description

Photodetector

[0001] The present disclosure relates to a light detection device, and more particularly to a light detection device that can suppress degradation in image quality of an image captured by a lensless camera.

[0002] A typical camera (camera with a lens) has a structure in which a lens is placed in front of the image sensor, the lens focuses light from the subject onto the image sensor's imaging surface, and the image captured by the image sensor is output as is as the final image.

[0003] In response to this, a lensless camera has been proposed in which the lens is eliminated and an optical modulation element is provided in front of the image sensor, an image made of modulated light modulated by the optical modulation element is captured by the image sensor as a modulated image, and then the captured modulated image is subjected to signal processing to reconstruct and output a final image (see Patent Document 1).

[0004] International Publication No. 2019 / 176349

[0005] In a lensless camera, since there is no lens as described above, light is incident on the imaging surface of the imaging element from various angles.

[0006] For this reason, for example, obliquely incident light may enter from outside the angle of view expected for the final image to be reconstructed, and it is generally known that obliquely incident light reduces the light receiving sensitivity of the image sensor.

[0007] However, when attempting to reconstruct the final image using signal processing, light from positions away from the center of the subject becomes obliquely incident light, which can make it impossible to properly reconstruct positions away from the center of the subject, resulting in a deterioration in the quality of the final image.

[0008] In rare cases, oblique incident light from an angle not intended for the subject may enter the imaging surface of the image sensor at a light intensity higher than the specified level. In this case, even though the light receiving sensitivity is low, the light is received as a signal of a certain level, which can have a negative effect on the final image reconstructed by signal processing, resulting in a deterioration in image quality.

[0009] Furthermore, a technique has been proposed in which object recognition processing is performed on modulated images without using reconstructed images. However, even in such cases, there is a risk of reduced recognition accuracy because modulated images, which reduce the image quality of reconstructed images, are used.

[0010] The present disclosure has been made in consideration of such circumstances, and in particular, aims to suppress degradation in image quality of images captured by a lensless camera.

[0011] The photodetection device according to a first aspect of the present disclosure includes an optical modulation element that modulates incident light to generate modulated light, and an image capture element that captures a modulated image based on the modulated light, wherein the image capture element is a photodetection device equipped with a high-sensitivity range control structure that controls a high-sensitivity range in which the incident angle of the incident light is near 0 degrees.

[0012] In a first aspect of the present disclosure, an optical modulation element that modulates incident light to generate modulated light and an imaging element that captures a modulated image based on the modulated light are provided, and a high sensitivity range in which the incident angle of the incident light is near 0 degrees is controlled in the imaging element.

[0013] A photodetection device according to a second aspect of the present disclosure includes an optical modulation element that modulates incident light to generate modulated light, and an image capture element that captures a modulated image based on the modulated light, wherein the image capture element is a photodetection device having a sensitivity control structure that controls the sensitivity of the incident light when the angle of incidence is near 90 degrees.

[0014] In a second aspect of the present disclosure, an optical modulation element that modulates incident light to generate modulated light and an imaging element that captures a modulated image based on the modulated light are provided, and the sensitivity of the imaging element to the incident light at an incident angle of approximately 90 degrees is controlled.

[0015] A photodetection device according to a third aspect of the present disclosure includes an optical modulation element that modulates incident light to generate modulated light, and an imaging element that captures a modulated image based on the modulated light, wherein the imaging element is a photodetection device equipped with a color mixing adjustment structure that adjusts the degree of color mixing.

[0016] In a third aspect of the present disclosure, an optical modulation element that modulates incident light to generate modulated light and an imaging element that captures a modulated image based on the modulated light are provided, and the degree of color mixing is adjusted in the imaging element.

[0017] FIG. 1 is a diagram illustrating the imaging principle of a camera with a lens. FIG. 2 is a diagram illustrating the imaging principle of a lensless camera (camera without a lens). FIG. 3 is a diagram illustrating that light receiving sensitivity decreases as the angle of incidence increases. FIG. 4 is a diagram illustrating an overview of a lensless camera according to the present disclosure. FIG. 5 is a diagram illustrating an example configuration of a lensless camera according to the present disclosure. FIG. 6 is a diagram illustrating an example configuration of an image sensor that serves as a reference. FIG. 7 is a diagram illustrating an example configuration of an image sensor (No. 6). FIG. 8 is a diagram illustrating an example configuration of an image sensor (No. 8). FIG. 9 is a diagram illustrating an example configuration of an image sensor (No. 9). FIG. 10 is a diagram illustrating an example configuration of an image sensor (No. 11). FIG. 12 is a diagram illustrating an example configuration of an image sensor (No. 13). FIG. 14 is a diagram illustrating an example configuration of an image sensor (No. 14). 15 is a diagram illustrating a configuration example (part 15) of an imaging element. 16 is a diagram illustrating a configuration example (part 15) of an imaging element.

[0018] Preferred embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings. In this specification and drawings, components having substantially the same functional configurations are designated by the same reference numerals, and redundant description will be omitted.

[0019] Hereinafter, embodiments for carrying out the present technology will be described. The description will be made in the following order: 1. Overview of the Present Disclosure 2. First Embodiment 3. Second Embodiment 4. Third Embodiment 5. Fourth Embodiment 6. Fifth Embodiment 7. Sixth Embodiment 8. Seventh Embodiment 9. Eighth Embodiment 10. Ninth Embodiment 11. Tenth Embodiment 12. Eleventh Embodiment 13. Twelfth Embodiment 14. Thirteenth Embodiment 15. Fourteenth Embodiment 16. Fifteenth Embodiment

[0020] <<1. Overview of the Present Disclosure>> The present disclosure particularly aims to suppress degradation in image quality of images reconstructed by a lensless camera. Therefore, before describing the overview of the present disclosure, first, a brief description will be given of the imaging principles of a general camera with a lens and a lensless camera (camera without a lens).

[0021] FIG. 1 is a diagram illustrating the imaging principle of a lens-equipped camera.

[0022] The lens-equipped camera 11 in FIG. 1 is composed of a lens 21, an image pickup device 22, and an image output unit 23.

[0023] The lens 21 focuses light emitted from each point on the subject Pi onto the imaging surface of the imaging element 22 .

[0024] The image sensor 22 is composed of a CMOS (Complementary Metal Oxide Semiconductor) image sensor or a CCD (Charge Coupled Device) image sensor, and generates pixel signals based on the amount of light collected by the lens 21, using pixels arranged in an array as units, and outputs the pixel signals to the image output unit 23 as a captured image Poa.

[0025] The image output unit 23 performs predetermined correction processing on the captured image Poa supplied from the image sensor 22 and outputs the image as an output image.

[0026] Here, the captured image Poa is an image in which each point on the subject Pi is inverted vertically and horizontally.

[0027] When the subject Pi is captured by the lens-equipped camera 11, the output image is an image that is close to the captured image Poa itself, and the image in the captured image Poa is an image that can be visually recognized as the subject Pi.

[0028] Next, the imaging principle of a lensless camera (camera without a lens) will be described with reference to FIG.

[0029] The lensless camera 31 in FIG. 2 is composed of an optical modulation element 41, an image pickup element 42, a signal processing unit 43, and an image output unit 44.

[0030] The image pickup device 42 and the image output section 44 are similar to the image pickup device 22 and the image output section 23 of the lens-equipped camera 11 in FIG. 1, and therefore a description thereof will be omitted.

[0031] The optical modulation element 41 has a substantially plate-like configuration, and is formed with a known two-dimensional pattern including an amplitude modulation region or a phase modulation region of light.

[0032] Amplitude modulation of light is achieved by using light-shielding materials or materials with different transmittances, while phase modulation of light is achieved by controlling the uneven structure within the surface of the optical modulation element, the refractive index distribution of a mask, or the effective refractive index obtained by controlling the density of materials with multiple refractive indices on the order of a size less than the wavelength.

[0033] Furthermore, light outside the modulation region may be shielded by any means. When imaging the subject Pi, the optical modulation element 41 modulates incident light emitted from each point on the subject Pi using a known two-dimensional phase amplitude pattern, and propagates the modulated light to a downstream imaging surface located a certain distance away. As a result, a light intensity distribution corresponding to the shape of the subject Pi and the shape of the two-dimensional pattern of the optical modulation element 41 is projected onto the imaging surface. Therefore, the image captured by the imaging element 42 is captured as a hazy modulated image that is not visible as the subject Pi, as shown in the captured image Pob.

[0034] The signal processing unit 43 performs predetermined signal processing based on the pattern of the optical modulation element 41 on the captured image Pob as a modulated image supplied from the imaging element 42, reconstructs a reconstructed image (also called a final image or restored image), and outputs it to the output unit 134.

[0035] The reconstructed image is visually recognized as the object Pi and corresponds to the captured image Poa in FIG.

[0036] The image output unit 44 then performs predetermined correction processing on the reconstructed image and outputs it as an output image.

[0037] The captured image Pob, which is captured as a modulated image, is captured in a state in which light from each point on the subject Pi is diffused and superimposed, and a reconstructed image is generated and output as an output image by performing signal processing on the image signal, which is the modulated image, according to the pattern of the optical modulation element 41 and the distance to the subject. Therefore, in the lensless camera 31, images of subjects at various distances can be reconstructed by signal processing according to the pattern of the optical modulation element 41 and the distance to the subject, and so as long as the subject is present within the angle of view, it is possible to reconstruct an image without causing a phenomenon known as out-of-focus.

[0038] Therefore, even if there is another subject in the background of the subject that was assumed at the time of image capture, by performing signal processing according to the distance to the subject, it is possible to generate a reconstructed image from the captured image, which is a modulated image, that focuses on the other subject in the background of the subject that was assumed at the time of image capture.

[0039] In this way, since a lens is not an essential component of a lensless camera, it is possible to achieve a low-profile configuration, and if it is possible to capture a modulated image that captures the subject within the angle of view, it is possible to reproduce images of subjects at various distances as reconstructed images regardless of the distance from the imaging position.

[0040] On the other hand, as shown in FIG. 3, the lensless camera 31 is not provided with a lens, and therefore, incident light passes through the optical modulation element 41 and enters the imaging element 42 from various angles.

[0041] However, the imaging element 42 generally has high sensitivity to light received from a direction close to the front of the imaging surface, that is, a direction perpendicular to the imaging surface, where the incident angle is small, but the sensitivity decreases as the incident angle increases.

[0042] More specifically, as shown by the waveform Ln of the characteristic graph F1 in FIG. 3, the light receiving sensitivity is a high value of around 1 when the incident angle is in the range close to 0 degrees, but drops sharply when the incident angle exceeds 20 degrees, reaching a minimum of 0.2 at 50 degrees, and then increases slightly thereafter, but remains below 0.4 even after 60 degrees.

[0043] Note that the characteristics graph F1 is merely an example, and although there are image sensors 42 with other characteristics, they generally have roughly similar trends. Also, the dashed-dotted line, dotted line, and solid line at the 0-degree, 30-degree, and 60-degree positions in the characteristics graph F1 correspond to the dashed-dotted line, dotted line, and solid line representing the trajectory of incident light in the left part of Figure 3, respectively.

[0044] As shown in the reconstructed image Pi' on the left side of Figure 3, which corresponds to the subject Pi in Figures 1 and 2, the area near the center of the image can be reconstructed with relatively high accuracy, but as the image moves away from the center position, it cannot be captured with sufficient sensitivity, and reconstruction cannot be performed properly.As for the peripheral area away from the center of the subject, the image may not be sufficiently reconstructed, as shown in black.

[0045] Furthermore, as shown by one subject Pn, if the light intensity of the solid line light corresponding to 60 degrees in the characteristic graph F1 is extremely high, it may be captured as unnecessary light, causing artifacts in the signal processing of the reconstructed image and behaving as noise.

[0046] Therefore, in order to realize incidence of incident light from within the angle of view that includes the subject Pi, the image sensor 42 has high oblique incidence sensitivity within the angle of view from an angle of incidence of approximately 0 degrees and low oblique incidence sensitivity outside the angle of view, i.e., an oblique incidence sensitivity characteristic such as that shown by the vertical waveform Lid in Figure 3. Note that although an example in which the angle of view range is 40 degrees is shown here, the angle of view range may be other angles. However, if the required angle of view range is sufficiently narrow, the image sensor 42 of the characteristic graph F1 in Figure 3 will suffice.

[0047] Therefore, in the present disclosure, assuming a case where the angle of view range is relatively wide, as shown in the lower part of Figure 4, instead of the image sensor 42, an image sensor 42' having characteristics as shown by the waveform Lp, which is close to the ideal waveform Lid of the characteristic graph F11, is provided.

[0048] As a result, the image sensor 42' can be configured to have a wide range of high light sensitivity where the incident angle is smaller than a predetermined value, for example, near 0 degrees, and a wide range of low light sensitivity where the incident angle is larger than the predetermined value, for example, near 90 degrees. This makes it possible to set a wide angle of view over which the subject can be captured, and to reduce the impact of unexpected high-intensity oblique incident light on the reconstructed image. In reality, the above-mentioned predetermined value assumes a half-angle of view range of about 20 degrees or more. If the range were to be smaller than about 20 degrees, it would be necessary to sacrifice resolution in order to prioritize thinness of the image sensor 42', and this is not practically preferable because it would be necessary to sacrifice thinness in order to prioritize resolution.

[0049] As a result, it is possible to achieve high quality images reconstructed using a lensless camera.

[0050] In addition, in Figure 4, the upper section shows a characteristic graph F1 of the lensless camera 31 and image sensor 42 similar to Figure 3, and the lower section shows a characteristic graph F11 of the lensless camera 31' and image sensor 42' of the present disclosure.

[0051] 2. First Embodiment Next, a configuration example of a lensless imaging device according to the present disclosure will be described with reference to Fig. 5. Fig. 5 is a side cross-sectional view of a lensless camera 111.

[0052] The lensless camera 111 in FIG. 5 is a so-called lensless camera, and includes an optical modulation element 131, an image pickup element 132, a signal processing unit 133, and an output unit 134.

[0053] The optical modulation element 131 is a plate-like structure made of a light-shielding material and provided in front of the image sensor 132, and is composed of, for example, a transmission region made of a hole-like opening that transmits incident light, and a light-shielding region that blocks other light. The openings and light-shielding regions of the optical modulation element 131 are configured in a predetermined pattern. Note that the transmission region may have various transmittances.

[0054] When the optical modulation element 131 receives light as incident light from the subject plane G1 indicated by the optical axis AX (in reality, the plane from which radiant light is emitted from a three-dimensional subject), it transmits the incident light through the transparent region, thereby modulating the incident light from the subject plane G1 as a whole and converting it into modulated light, and the converted modulated light is received by the image sensor 132 to be captured as a modulated image.

[0055] The image sensor 132 is composed of a CMOS (Complementary Metal Oxide Semiconductor) image sensor or a CCD (Charge Coupled Device) image sensor, captures modulated light obtained by modulating incident light from an object plane G1 using an optical modulation element 131, and outputs the modulated signal G2 consisting of a pixel-by-pixel signal to the signal processing unit 133. More specifically, the image sensor 132 generates RAW data based on the image consisting of the modulated signal G2 and outputs the RAW data to the signal processing unit 133.

[0056] The optical modulation element 131 is basically configured so that the imaging element 132 receives only modulated light that has been modulated by passing through the optical modulation element 131. The optical modulation element 131 may be divided into multiple members.

[0057] Furthermore, the size of the transmission area formed in the optical modulation element 131 is at least larger than the pixel size of the image sensor 132. Furthermore, a minute gap of distance d is provided between the image sensor 132 and the optical modulation element 131.

[0058] More specifically, the optical modulation element 131 is an optical modulation element that performs amplitude and phase modulation on a wavefront having an in-plane distribution in which the magnitude of the PSF (Point Spread Function) is 5% or more of the size (diagonal length) L1 of the image sensor 132 at any distance to the subject, and light of a plurality of non-continuous incident angles is superimposed over at least one pixel or more. Note that the magnitude of the PSF here refers to the distance between the most distant points when the threshold is set to 10% of the peak intensity.

[0059] Furthermore, when the size (diagonal length) of the image sensor 132 is L1 and the distance between the surface that functions as the optical modulation element 131 and the surface farthest from the image sensor 132 and the image sensor 132 is L2, it is assumed that 0.005 < L2 / L1 < 0.9.

[0060] The signal processing unit 133 performs predetermined signal processing according to the pattern of the optical modulation element 131 based on the captured modulated image (modulated signal G2 in Figure 5) consisting of RAW data supplied from the imaging element 132, reconstructs a reconstructed image (also referred to as a final image or restored image) (image G3 in Figure 5) and outputs it to the output unit 134.

[0061] The output unit 134 applies predetermined correction processing to the final image supplied from the signal processing unit 133 and outputs the result as an image signal.

[0062] In this disclosure, an example will be described in which a reconstructed image is reconstructed by performing predetermined signal processing according to the pattern of the optical modulation element 131 based on an image consisting of a modulated signal, but the signal processing unit 133 for reconstructing the reconstructed image is not a required component.

[0063] For example, when performing object recognition processing of a subject using the imaging results, a recognition processing unit that recognizes the object from the imaging results is required, and this recognition processing unit may be one that recognizes the object based on a reconstructed image, or one that recognizes the object based on a modulated image consisting of a modulated signal.

[0064] That is, when an object is to be recognized by providing an object recognition unit, the image required for the object recognition process of the object recognition unit may be either a reconstructed image or a modulated image made up of a modulated signal.

[0065] Therefore, when the imaging results of the lensless camera 111 are used for, for example, object recognition processing of a subject, the signal processing unit 133 can be considered not to be an essential component.

[0066] However, signal processing is omitted only when a reconstructed image is not necessary so that object recognition processing of the subject can be performed based on the modulated image. Therefore, in this specification, we will describe an example in which the lensless camera 111 is provided with a signal processing unit 133, and will also describe an example in which the signal processing unit 133 is not provided.

[0067] <Example of Reference Configuration of Image Sensor> Next, an example of the reference configuration of the image sensor 132 will be described with reference to FIG.

[0068] It should be noted that the "reference configuration example" of the imaging element 132 is a configuration that has the problem of the present disclosure, but does not exclude its use, and is a configuration that can be used as needed.

[0069] In other words, for example, when the required angle of view is narrow and the device is used in an environment where there is no need to consider high-intensity oblique incident light from outside the expected angle of view, no issues arise, so it can be an option.

[0070] However, when the angle of view is widened as envisioned in this disclosure, or in an environment where high-intensity oblique incident light occurs from outside the envisioned angle of view, the above-mentioned problems may arise in the "standard configuration example" of the image sensor 132.

[0071] The left part of Fig. 6 is a side cross-sectional view of two pixels of the image sensor 132, where the refractive index is expressed by density, and a color scale of the refractive index expressed by density is shown in the center of the figure. The right part of Fig. 6 shows the relative sensitivity curves of R, Gr, Gb, and B for obliquely incident light (shown for a light source wavelength of 550 nm).

[0072] The imaging element 132 is configured, from top to bottom in the drawing, with the direction of incident light being from top to bottom, and is composed of an OCL (On Chip Lens) 151, a color filter 152, an inter-pixel light shielding portion 153, and a PD (Photodiode) 154.

[0073] The OCL 151 collects the incident light and focuses it on the light receiving surface of the PD 154 .

[0074] The color filter 152 is an optical band-pass filter that selectively transmits predetermined wavelength bands of R, Gr, Gb, and B from the incident light.

[0075] The inter-pixel light-shielding portion 153 is made of a light-shielding material, and prevents leakage of incident light between pixels, thereby suppressing crosstalk between adjacent pixels.

[0076] The PD (photodiode) 154 is composed of a photoelectric conversion element, and generates a pixel signal according to the amount of incident light.

[0077] The relative sensitivity curve on the right side of FIG. 6 is a curve showing the relationship between the incident angle and normalized sensitivity at the image sensor 132 on the left side of FIG. 6, and shows an example of incident light when the light source wavelength is 550 nm.

[0078] As shown in the right part of Figure 6, for incident light of Gr and Gb with a light source wavelength of 550 nm, the sensitivity is highest when the incident angle is 0, and gradually decreases to about 0.8 in the range up to about 20 degrees. Thereafter, at angles above 20 degrees, the sensitivity drops sharply to 0.2 or less at angles above 40 degrees.

[0079] Furthermore, since R and B are not the wavelengths of the light source, they indicate the sensitivity state to obliquely incident light, i.e., the degree of crosstalk. In other words, the higher the R and B values ​​become with an increase in obliquely incident light, the greater the impact of crosstalk.

[0080] In addition, in the image sensor 132 on the left side of Figure 6, as shown by the relative sensitivity characteristics shown on the right side of Figure 6, sensitivity drops sharply when the angle of incidence exceeds 20 degrees, so that incident light from areas away from the center of the subject cannot be sufficiently received, and there is a possibility that the signal processing unit 133 will not be able to obtain a modulation signal sufficient to obtain a reconstructed image.

[0081] <Configuration Example (1) of Image Sensor According to the Present Disclosure> Therefore, in the present disclosure, the principal curvature of the OCL 151 is reduced in order to widen the range in which the relative sensitivity characteristics are high when the incident angle is near 0 degrees, in other words, to widen the range up to the incident angle at which the relative sensitivity characteristics drop sharply.

[0082] Fig. 7 shows an example configuration of an image sensor 132A that widens the range of incident angles at which a rapid drop in relative sensitivity occurs. Note that in the image sensor 132A in Fig. 7, the same components as those in the image sensor 132 in Fig. 6 are denoted by the same reference numerals, and descriptions thereof will be omitted where appropriate. Furthermore, in the first embodiment of the lensless camera 111 of the present disclosure, the image sensor 132A is provided instead of the image sensor 132.

[0083] That is, the imaging element 132A on the left side of FIG. 7 differs from the imaging element 132 in FIG. 6 in that an OCL 151A is provided instead of the OCL 151.

[0084] The OCL 151A has a configuration in which the principal curvature of the OCL 151 is reduced. With the OCL 151A, in the relative sensitivity characteristics on the right side of Fig. 7, the curves of Gr and Gb of the image sensor 132A shown by the solid lines show a gradual decrease in sensitivity with changes in the angle of incidence, compared to the curves of Gr and Gb of the image sensor 132 shown by the dotted lines.

[0085] As a result, it is possible to widen the high sensitivity range where the incident angle is close to 0 degrees, in other words, to widen the range up to the incident angle where the relative sensitivity characteristic drops sharply.

[0086] Note that the OCL 151A in FIG. 7 has a principal curvature of approximately 0. However, if the principal curvature can be made smaller than that of the OCL 151 in FIG. 6, the high sensitivity range where the angle of incidence is close to 0 degrees can be widened. For example, by setting the principal curvature to approximately 0≦pixel pitch×principal curvature≦2.0, it is possible to sufficiently widen the high sensitivity range where the angle of incidence is close to 0 degrees compared to the image sensor 132.

[0087] Furthermore, by changing the principal curvature of the OCL 151A within the range of 0≦pixel pitch×principal curvature≦2.0, it is possible to control the high sensitivity range where the incident angle is close to 0 degrees.

[0088] That is, by changing the principal curvature of the OCL 151A and bringing the ratio of the inter-pixel pitch to the principal curvature closer to 0, it is possible to control the high sensitivity range where the incident angle is close to 0 degrees so as to be set wider. Conversely, by changing the principal curvature of the OCL 151A and bringing the ratio of the inter-pixel pitch to the principal curvature closer to 2.0, it is possible to control the high sensitivity range where the incident angle is close to 0 degrees so as to be set in a narrower range than when the ratio of the inter-pixel pitch to the principal curvature is 0.

[0089] However, as shown in the right part of Figure 7 , if the principal curvature is reduced to near 0, the R and B of the image sensor 132A (shown by the solid line) will be higher than the R and B of the image sensor 132 (shown by the dotted line) over almost the entire range, regardless of the angle of incidence, making crosstalk more likely to occur. Furthermore, for example, when the required angle of view is narrow and the device is used in an environment where it is not necessary to anticipate high-intensity oblique incident light from outside the expected angle of view, it is also possible to select the reference image sensor 132 described with reference to Figure 6 instead of the image sensor 132A. Therefore, when considering the image sensor 132 shown in Figure 6 , the pixel pitch x principal curvature of the OCL 151 can be set to, for example, about 2.0. Therefore, by changing the principal curvature of the OCL 151A within the range of 0 ≦ pixel pitch x principal curvature ≦ 2.0, it is possible to control the high-sensitivity range where the angle of incidence is close to 0 degrees. Furthermore, when the principal curvature of the OCL 151A is near 0, the OCL 151A can be considered to have a structure that does not substantially have a light-collecting function, or in other words, the OCL 151A can be considered to have the same effect as a structure without the OCL 151A. Therefore, even when the OCL 151A itself is removed from the image sensor 132A on the left side of Figure 7, the same effect as when the OCL 151A with a principal curvature near 0 is provided can be obtained.

[0090] <<3. Second embodiment>> <Configuration example (part 2) of the image sensor according to the present disclosure>> Based on the configuration of the image sensor 132A in the first embodiment, an inter-pixel isolation structure may be configured in an area including the OCL 151 and the color filter 152 in order to suppress crosstalk.

[0091] Fig. 8 shows an example configuration of an image sensor 132B having an inter-pixel separation structure. Note that in the image sensor 132B of Fig. 8, the same components as those in the image sensor 132 of Fig. 6 are denoted by the same reference numerals, and descriptions thereof will be omitted where appropriate. Furthermore, in a second embodiment of the lensless camera 111 of the present disclosure, the image sensor 132 is replaced with the image sensor 132B.

[0092] 8 differs from the image sensor 132 in FIG. 6 in that an inter-pixel light shielding portion 161 is provided even in the area where the OCL 151 and the color filter 152 are provided, instead of the inter-pixel light shielding portion 153. The inter-pixel light shielding portion 161 is an inter-pixel separation structure made of a light shielding member that optically separates the pixels that make up the image sensor 132B.

[0093] With this configuration, the R and B of the image sensor 132B, shown by the solid line in the relative sensitivity characteristics on the right side of Figure 8, have lower sensitivity characteristics than the R and B of the image sensor 132, shown by the dotted line, particularly in the range where the angle of incidence is greater than 30 degrees, indicating that crosstalk is suppressed.

[0094] Furthermore, with this configuration, the Gr and Gb of image sensor 132B, shown by the solid line in the relative sensitivity characteristic on the right side of Figure 8, have lower sensitivity characteristics than the Gr and Gb of image sensor 132, shown by the dotted line, particularly in the range where the incident angle is greater than 40 degrees, and the light receiving sensitivity in areas away from the center position of the subject is suppressed, indicating that even if oblique incident light of strong light intensity occurs from an unexpectedly large incident angle, the impact can be reduced.

[0095] In FIG. 8, the inter-pixel light shielding portion 161 is provided between adjacent pixels, ahead of the PD 154 in the direction of incidence of incident light, at a height that spans the area where the color filter 152 and the OCL 151 are provided.

[0096] However, it is possible to suppress crosstalk even if the height of the inter-pixel light-shielding portion 161 is lower than that shown in FIG. 8 , and for example, within a range of approximately 0.3≦height of the inter-pixel light-shielding portion 161 / inter-pixel pitch≦3, it is possible to control the influence of obliquely incident light with strong light intensity from an unexpectedly large angle of incidence and the degree of suppression of crosstalk.

[0097] That is, by setting the height of the inter-pixel light shielding portion 161 low and setting the height of the inter-pixel light shielding portion 161 / inter-pixel pitch to a value close to 0.3, it is possible to set the degree of suppression of crosstalk and the influence of obliquely incident light of strong light intensity from an unexpectedly large incident angle to a weaker level. Conversely, by setting the height of the inter-pixel light shielding portion 161 high and setting the height of the inter-pixel light shielding portion 161 / inter-pixel pitch to a value close to 3, it is possible to set the degree of suppression of crosstalk and the influence of obliquely incident light of strong light intensity from an unexpectedly large incident angle to a stronger level.

[0098] <<4. Third embodiment>> <Configuration example (third) of the image sensor according to the present disclosure>> In the above, an example has been described in which the inter-pixel light shielding portion 161 is provided upstream of the PD 154 to a height spanning the OCL 151 and the color filter 152 in order to suppress crosstalk, thereby suppressing the effects of crosstalk and strong, obliquely incident light from an unexpectedly large angle of incidence. However, crosstalk may also be suppressed by providing the inter-pixel light shielding portion within the PD 154.

[0099] Fig. 9 shows a configuration example of an image sensor 132C in which an inter-pixel isolation structure is provided within the PD 154. Note that in the image sensor 132C in Fig. 9, the same components as those in the image sensor 132 in Fig. 6 are denoted by the same reference numerals, and descriptions thereof will be omitted as appropriate. Furthermore, in a third embodiment of the lensless camera 111 of the present disclosure, the image sensor 132C is provided in place of the image sensor 132.

[0100] That is, the imaging element 132C on the left side of FIG. 9 differs from the imaging element 132 of FIG. 6 in that an inter-pixel light-shielding portion 171 is provided in the PD 154.

[0101] With this configuration, the sensitivity characteristics of the image sensor 132C, shown by the solid line in the relative sensitivity characteristics on the right side of Figure 9, are lower over almost the entire range of R and B than those of the image sensor 132, shown by the dotted line, indicating that crosstalk is suppressed.

[0102] In FIG. 9, the inter-pixel light shielding portion 171 has a height of a predetermined range from the incident surface of the PD 154 to the bottom, where the incident surface of the incident light of the PD 154 is the top and the bottom in the figure is the bottom.

[0103] However, crosstalk can be suppressed even if the height of the inter-pixel light shielding portion 171 is other than that shown in FIG. 9 , and the degree of crosstalk suppression can be controlled by the height, for example, within the range of approximately 0.2≦height of the inter-pixel light shielding portion 171 / inter-pixel pitch≦2.

[0104] That is, it is possible to weaken the degree of crosstalk suppression by setting the height of the inter-pixel light-shielding portion 171 low, or conversely, it is possible to strengthen the degree of crosstalk suppression by setting the height of the inter-pixel light-shielding portion 171 high.

[0105] <<5. Fourth embodiment>> <Configuration example (part 4) of image sensor according to the present disclosure> Furthermore, an inter-pixel isolation structure may be formed by combining inter-pixel light shielding portion 161 in image sensor 132B of FIG. 8 and inter-pixel light shielding portion 171 in image sensor 132C of FIG. 9 .

[0106] FIG. 10 shows an example of the configuration of an image sensor 132D in which an inter-pixel isolation structure is formed by combining the inter-pixel light shielding portion 161 in the image sensor 132B in FIG. 8 and the inter-pixel light shielding portion 171 in the image sensor 132C in FIG.

[0107] 10, the same components as those of the image sensor 132 in FIG. 6 are denoted by the same reference numerals, and the description thereof will be omitted as appropriate. In addition, in the fourth embodiment of the lensless camera 111 of the present disclosure, the image sensor 132 is replaced with the image sensor 132D.

[0108] 10 differs from the image sensor 132 in FIG. 6 in that inter-pixel light shielding portions 161 and 171 are provided instead of the inter-pixel light shielding portion 153. In FIG.

[0109] With this configuration, the sensitivity characteristics of the image sensor 132D, shown by the solid line in the relative sensitivity characteristics on the right side of Figure 10, are lower across the entire range of R and B than those of the image sensor 132, shown by the dotted line, indicating that crosstalk is suppressed.

[0110] Furthermore, with this configuration, the Gr and Gb of the image sensor 132D shown by the solid line in the relative sensitivity characteristic on the right side of Figure 10 have lower sensitivity characteristics than the Gr and Gb of the image sensor 132 shown by the dotted line, particularly in the range where the incident angle is greater than 40 degrees, and this shows that the light receiving sensitivity in areas away from the center position of the subject is suppressed, and the influence of oblique incident light with strong light intensity from an unexpectedly large incident angle can be reduced.

[0111] The inter-pixel light shielding portions 161 and 171 in FIG. 10 can control the degree of suppression of crosstalk and the influence of strong, obliquely incident light from an unexpectedly large incident angle by adjusting their respective heights.

[0112] 6. Fifth Embodiment Fifth Configuration Example of Image Sensor of Present Disclosure Furthermore, the configuration of the image sensor 132D in FIG. 10 may be combined with the OCL 151A in FIG. 7 and the inter-pixel light shielding unit 171 in FIG.

[0113] The left part of Fig. 11 shows an image sensor 132E that combines the OCL 151A of Fig. 7 and the inter-pixel light shielding portion 171 of Fig. 10. In addition, in the fifth embodiment of the lensless camera 111 of the present disclosure, the image sensor 132E is provided instead of the image sensor 132.

[0114] With the configuration shown in the left part of Figure 11, the relative sensitivity characteristics of the image sensor 132E are such that, as shown in the right part of Figure 11, the Gr, Gb curves of the image sensor 132E shown by the solid lines gradually decrease in sensitivity with changes in the angle of incidence, compared to the Gr, Gb curves of the image sensor 132 shown by the dotted lines, thereby widening the high sensitivity range where the angle of incidence is close to 0 degrees.

[0115] Moreover, over the entire range of R and B of the image sensor 132E shown by the solid line, the sensitivity characteristics are lower than those of R and B of the image sensor 132 shown by the dotted line, indicating that crosstalk is suppressed.

[0116] In the inter-pixel light shielding portion 171 of FIG. 11, the influence of strong, obliquely incident light from an unexpectedly large incident angle and the degree of suppression of crosstalk can also be controlled by adjusting the height.

[0117] Also, in the OCL 151A of FIG. 11, by changing the principal curvature, it is possible to control the high sensitivity range where the incident angle is close to 0 degrees.

[0118] 7. Sixth Embodiment Configuration Example (No. 6) of Image Sensor of the Present Disclosure The OCL 151A in FIG. 7 and the inter-pixel light shielding portion 161 in FIG. 8 may be combined.

[0119] The left part of Fig. 12 shows an image sensor 132F that combines the OCL 151A of Fig. 7 and the inter-pixel light shielding portion 161 of Fig. 8. In addition, in a sixth embodiment of the lensless camera 111 of the present disclosure, an image sensor 132F is provided instead of the image sensor 132.

[0120] With the configuration shown in the left part of Figure 12, the relative sensitivity characteristics of the image sensor 132F are such that, as shown in the right part of Figure 12, the Gr and Gb curves of the image sensor 132F shown by the solid lines gradually decrease in sensitivity with changes in the angle of incidence compared to the Gr and Gb curves of the image sensor 132 shown by the dotted lines, thereby widening the high sensitivity range where the angle of incidence is close to 0 degrees.

[0121] Furthermore, in a portion of the range of R and B of the image sensor 132F indicated by the solid line, the sensitivity characteristics are lower than those of R and B of the image sensor 132 indicated by the dotted line, indicating that crosstalk is suppressed.

[0122] In the inter-pixel light shielding portion 161 of FIG. 12, the influence of strong, obliquely incident light from an unexpectedly large incident angle and the degree of suppression of crosstalk can also be controlled by adjusting the height.

[0123] Also, in the OCL 151A of FIG. 12, by changing the principal curvature, it is possible to control the high sensitivity range where the incident angle is close to 0 degrees.

[0124] 8. Seventh Embodiment Configuration Example (No. 7) of Image Sensor of the Present Disclosure Furthermore, the OCL 151A in FIG. 7, the inter-pixel light shielding portion 161 in FIG. 8, and the inter-pixel light shielding portion 171 in FIG. 9 may be combined.

[0125] The left part of Fig. 13 shows an image sensor 132G that combines the OCL 151A of Fig. 7, the inter-pixel light shielding portion 161 of Fig. 8, and the inter-pixel light shielding portion 171 of Fig. 9. In addition, in the seventh embodiment of the lensless camera 111 of the present disclosure, an image sensor 132G is provided instead of the image sensor 132.

[0126] With the configuration shown in the left part of Figure 13, the relative sensitivity characteristics of the image sensor 132G are such that, as shown in the right part of Figure 13, the Gr, Gb curves of the image sensor 132G shown by the solid lines gradually decrease in sensitivity with changes in the angle of incidence, compared to the Gr, Gb curves of the image sensor 132 shown by the dotted lines, thereby widening the high sensitivity range where the angle of incidence is close to 0 degrees.

[0127] Furthermore, in almost the entire range except for the vicinity of 0 degrees of R and B of the image sensor 132G shown by the solid line, the sensitivity characteristics are lower than those of R and B of the image sensor 132 shown by the dotted line, indicating that crosstalk is suppressed.

[0128] In the inter-pixel light shielding portions 161 and 171 shown in FIG. 13, the influence of strong, obliquely incident light from an unexpectedly large incident angle and the degree of suppression of crosstalk can also be controlled by adjusting the height.

[0129] Also, in the OCL 151A of FIG. 13, by changing the principal curvature, it is possible to control the high sensitivity range where the incident angle is close to 0 degrees.

[0130] <<9. Eighth Embodiment>> <Configuration Example (No. 8) of Image Sensor According to the Present Disclosure>> In the above, an example has been described in which at least one of the OCL 151A in Fig. 7, the inter-pixel light shielding portion 161 in Fig. 8, and the inter-pixel light shielding portion 171 in Fig. 9 is used. However, apart from these configurations, an aperture structure may be provided to suppress crosstalk.

[0131] 14 shows an example of the configuration of an image sensor 132H that is provided with an aperture structure. In addition, in the eighth embodiment of the lensless camera 111 of the present disclosure, an image sensor 132H is provided instead of the image sensor 132.

[0132] The image sensor 132H in FIG. 14 differs from the image sensor 132 in FIG. 6 in that an aperture structure 181 is provided instead of the inter-pixel light shielding portion 153.

[0133] The diaphragm structure 181 has a function of blocking, for each pixel, the incident light that has passed through the OCL 151 and the color filter 152 and is far from the pixel center, and adjusting the angle of incidence (field of view) and amount of light (brightness) of the incident light at the pixel center. Since the diaphragm structure 181 can be prepared with different angles of incidence (field of view) and amounts of light (brightness) of the transmitted incident light, it is possible to adjust the amount of diaphragm diaphragm aperture related to the angle of incidence (field of view) and amount of light (brightness) of the incident light by designing the diaphragm using, for example, the area and shape as parameters, and depending on the amount of diaphragm aperture, it is possible to adjust the degree of suppression of crosstalk and the degree of reduction of the influence of strong, oblique incident light from an unexpectedly large angle of incidence.

[0134] With the configuration shown in the left part of Figure 14, the relative sensitivity characteristics of the image sensor 132H are lower than the R and B of the image sensor 132 shown by the dotted line in almost the entire range except for the vicinity of 0 degrees of R and B of the image sensor 132H shown by the solid line, as shown in the right part of Figure 14, making it possible to suppress crosstalk.

[0135] Furthermore, as shown in the right part of Figure 14, particularly in the range of large incident angles in areas away from the center position of the subject, the Gr and Gb curves of image sensor 132H shown by the solid line are lower than the Gr and Gb curves of image sensor 132 shown by the dotted line, indicating that the light receiving sensitivity in areas away from the center position of the subject is suppressed and that the effects of oblique incident light with strong light intensity from an unexpectedly large incident angle can be reduced.

[0136] However, compared to the Gr and Gb curves of the image sensor 132 shown by the dotted lines, the Gr and Gb curves of the image sensor 132H shown by the solid lines drop sharply with changes in the incident angle, so the high sensitivity range where the incident angle is close to 0 degrees is narrowed.

[0137] <<10. Ninth Embodiment>> <Configuration Example (No. 9) of Image Sensor According to the Present Disclosure>> In the above, an example has been described in which an aperture structure is provided to suppress crosstalk. However, instead of the inter-pixel light-shielding portion 161 of FIG. 8 , an inter-pixel light-guiding structure may be provided to widen the high-sensitivity range where the angle of incidence is close to 0 degrees.

[0138] The left part of Fig. 15 shows a configuration example of an image sensor 132I in which an inter-pixel light guide structure is provided instead of the inter-pixel light shielding portion 161 of Fig. 8. In addition, in a ninth embodiment of the lensless camera 111 of the present disclosure, an image sensor 132I is provided instead of the image sensor 132.

[0139] The imaging element 132I in FIG. 15 differs from the imaging element 132B in FIG. 8 in that an inter-pixel light guide portion 191 is provided instead of the inter-pixel light shielding portion 161.

[0140] The inter-pixel light-guiding section 191 is made of a material with a lower refractive index than the surrounding area, and has the function of confining and guiding incident light within the pixel. The material with a lower refractive index than the surrounding area may be any material that has a light-guiding structure, such as a gap.

[0141] With the configuration shown in the left part of Figure 15, the relative sensitivity characteristics of the image sensor 132I are such that, as shown in the right part of Figure 15, the Gr and Gb curves of the image sensor 132I shown by the solid lines gradually decrease with changes in the angle of incidence compared to the Gr and Gb curves of the image sensor 132 shown by the dotted lines, making it possible to widen the high sensitivity range where the angle of incidence is close to 0 degrees.

[0142] However, the image sensor 132I shown by the solid line has higher sensitivity characteristics over substantially the entire range of R and B than the image sensor 132 shown by the dotted line, and crosstalk is more likely to occur.

[0143] The inter-pixel light-guiding section 191 can control the high sensitivity range where the incident angle is close to 0 degrees by adjusting the height with respect to the incident direction of the incident light.

[0144] <<11. Tenth embodiment>> <Configuration example (10) of the image pickup element according to the present disclosure>> In the above, an example has been described in which an inter-pixel light-guiding structure is provided in place of the inter-pixel light-shielding portion 161 of FIG. 8 to widen the high-sensitivity range in which the incident angle is close to 0 degrees. However, it is also possible to provide an OCL 151A in place of the OCL 151 to further widen the high-sensitivity range in which the incident angle is close to 0 degrees.

[0145] The left part of Fig. 16 shows an example configuration of an image sensor 132J in which the OCL 151A of Fig. 7 is provided instead of the OCL 151 in the configuration of the image sensor 151I of Fig. 15. In addition, in a tenth embodiment of the lensless camera 111 of the present disclosure, the image sensor 132 is configured to be provided instead of the image sensor 132.

[0146] The imaging device 132J in FIG. 16 differs from the imaging device 132I in FIG. 15 in that the OCL 151A in FIG. 7 is provided instead of the OCL 151.

[0147] With the configuration shown in the left part of Fig. 16, the relative sensitivity characteristics of the image sensor 132J are such that the Gr and Gb curves of the image sensor 132J shown by the solid lines gradually decrease compared to the Gr and Gb curves of the image sensor 132 shown by the dotted lines, as shown in the right part of Fig. 16, making it possible to widen the high sensitivity range where the angle of incidence is close to 0 degrees. Furthermore, the Gr and Gb curves of the image sensor 132J decrease more gradually with changes in the angle of incidence than the Gr and Gb curves of the image sensor 132I shown on the right part of Fig. 15, making it possible to widen the high sensitivity range where the angle of incidence is close to 0 degrees even compared to the image sensor 132I.

[0148] Although not shown, an inter-pixel light shielding portion 171 as shown in FIG. 9 may be further added, and such a configuration makes it possible to suppress crosstalk.

[0149] <<12. Eleventh embodiment>> <Configuration example (eleventh) of the image pickup element according to the present disclosure>> In the above, an example has been described in which the inter-pixel light-guiding unit 191 and the OCL 151A are provided to widen the high-sensitivity range in which the incident angle is close to 0 degrees. However, the high-sensitivity range in which the incident angle is close to 0 degrees may be widened by removing the color filter 152 and converting to monochrome.

[0150] The left part of Fig. 17 shows a configuration example of the image sensor 132K from which the color filter 152 in Fig. 6 has been removed. In addition, in the eleventh embodiment of the lensless camera 111 of the present disclosure, the image sensor 132K is provided instead of the image sensor 132.

[0151] The imaging element 132K in Figure 17 differs from the imaging element 132 in Figure 6 in that the color filter 152 is removed and, instead of the OCL 151, an OCL 151B is provided, which includes the area where the color filter 152 has been removed.

[0152] With the configuration shown in the left part of Figure 17, the relative sensitivity characteristics of the image sensor 132K are such that, as shown in the right part of Figure 17, the curve of the image sensor 132K shown by the solid line gradually decreases with changes in the angle of incidence compared to the Gr and Gb curves of the image sensor 132 shown by the dotted line, making it possible to widen the high sensitivity range where the angle of incidence is close to 0 degrees.

[0153] However, in the image sensor 132K shown by the solid line, in the range of large angles of incidence, the sensitivity characteristics are higher than the R and B of the image sensor 132 shown by the dotted line, and at first glance it may appear that crosstalk to adjacent pixels is more likely to occur and become a problem, but in the absence of color filters, it can also be seen as an improvement in the sensitivity of channels of the same color, and particularly in a lensless camera in which focusing light to a single point at the imaging stage is not an ideal, this can be seen as a wide control over the high sensitivity range and is acceptable in practical use.

[0154] In other words, the high sensitivity range where the angle of incidence is close to 0 degrees can be controlled by using a configuration in which the color filter 152 is removed, as in the image sensor 132K of Figure 17, or a configuration in which the color filter 152 is provided, as in the image sensor 132 of Figure 6.

[0155] <<13. Twelfth embodiment>> <Configuration example (12) of the image pickup element according to the present disclosure>> In the above, an example in which the color filter 152 is removed to produce a monochrome image has been described. However, the height of the OCL 151 may be reduced to widen the high sensitivity range where the angle of incidence is close to 0 degrees.

[0156] The left part of Fig. 18 shows a configuration example of an image sensor 132L that is a lower-profile version of the OCL 151 of Fig. 6. Note that in the left part of Fig. 18, the image sensor 132 of Fig. 6 is written on the left side of the left part for comparison with the image sensor 132L. Furthermore, in a twelfth embodiment of the lensless camera 111 of the present disclosure, the image sensor 132 is configured to be provided instead of the image sensor 132.

[0157] 18 differs from the image sensor 132 of FIG. 6 in that an OCL 151C, which is a lower-profile version of the OCL 151, is provided instead of the OCL 151. That is, the OCL 151 has a height H1, while the OCL 151C has a height H2 (

[0158] With the configuration shown in the left part of Figure 18, the relative sensitivity characteristics of the image sensor 132L are such that, as shown in the right part of Figure 18, the curve of the image sensor 132L shown by the solid line gradually decreases with changes in the incident angle compared to the Gr and Gb curves of the image sensor 132 shown by the dotted line, thereby widening the high sensitivity range where the incident angle is close to 0 degrees.

[0159] It has also been shown that the light sensitivity in areas away from the center of the subject is suppressed, making it possible to reduce the effects of obliquely incident light with strong light intensity from an unexpectedly large angle of incidence.

[0160] Furthermore, by adjusting the height of the upper layer, it is possible to control the width of the high sensitivity range and the degree of reduction in the influence of strong, obliquely incident light from an unexpectedly large incident angle.

[0161] More specifically, by adjusting the height of the upper layer within a range of, for example, 0 < height of upper layer / pixel pitch ≦ 0.7, it is possible to adjust the degree to which the effect of strong, obliquely incident light from an unexpectedly large angle of incidence is reduced.

[0162] ​That is, by controlling the height of the upper layer portion, including the height of OCL 151C, and setting the height of the upper layer portion / pixel pitch to a state close to 0, it is possible to set the width of the high sensitivity range wide and to set a strong degree of reduction in the influence of obliquely incident light of strong light intensity from an unexpectedly large incident angle. Conversely, by controlling the height of the upper layer portion, including the height of OCL 151C, and setting the height of the upper layer portion / pixel pitch to a state close to 0.5, it is possible to set the width of the high sensitivity range narrow and to set a weak degree of reduction in the influence of obliquely incident light of strong light intensity from an unexpectedly large incident angle.

[0163] <<14. Thirteenth embodiment>> <Configuration example (13) of the image pickup element according to the present disclosure>> Furthermore, the color filter 152 may be removed to convert to monochrome, and the height of the OCL 151A may be reduced to widen the high sensitivity range where the angle of incidence is close to 0 degrees.

[0164] 19 shows an example of the configuration of an image sensor 132M in which the color filter 152 has been removed to produce a monochrome image and the OCL 151A has been reduced in height. In addition, in a thirteenth embodiment of the lensless camera 111 of the present disclosure, an image sensor 132M is provided in place of the image sensor 132.

[0165] The image sensor 132M in FIG. 19 differs from the image sensor 132A in FIG. 7 in that the OCL 151A is replaced with an OCL 151D that is thinner than the OCL 151A, and the color filter 152 is removed.

[0166] With the configuration shown in the left part of Figure 19, the relative sensitivity characteristics of the image sensor 132M, as shown in the right part of Figure 19, are such that the curve of the image sensor 132M shown by the solid line gradually decreases with changes in the angle of incidence compared to the Gr and Gb curves of the image sensor 132 shown by the dotted line, making it possible to widen the high sensitivity range where the angle of incidence is close to 0 degrees.

[0167] Furthermore, in the image pickup element 132M indicated by the solid line, crosstalk is suppressed over the entire range by being converted to monochrome.

[0168] In other words, the high sensitivity range where the angle of incidence is close to 0 degrees can be controlled by using a configuration in which the color filter 152 is removed, as in the image sensor 132M of FIG. 19, or a configuration in which the color filter 152 is provided, as in the image sensor 132 of FIG. 6.

[0169] <<15. Fourteenth Embodiment>> <Configuration Example (14) of the Image Sensor According to the Present Disclosure>> In the above, an example has been described in which the color filter 152 is removed to convert to monochrome, and the OCL 151D is used, which is a low-curvature OCL 151A that has been reduced in height. However, it is also possible to remove the OCL 151 and form the inter-pixel light-shielding portion in a louver shape so that it protrudes toward the front side, which is opposite the incident direction of the incident light, with respect to the incident surface of the color filter 152, thereby widening the high-sensitivity range where the incident angle is close to 0 degrees and suppressing crosstalk.

[0170] 20 shows a configuration example of an image sensor 132N in which the OCL 151 is removed and the inter-pixel light-shielding portion is formed in a louver shape so as to protrude toward the front side, which is the opposite direction to the incident light, relative to the incident surface of the color filter 152. Also, in a fourteenth embodiment of the lensless camera 111 of the present disclosure, an image sensor 132N is provided instead of the image sensor 132.

[0171] The image sensor 132N in Figure 20 differs from the image sensor 132 in Figure 6 in that the OCL 151 is removed, and instead of the inter-pixel light-shielding portion 153, an inter-pixel light-shielding portion 201 formed in a louver shape is provided so as to protrude toward the front side, which is in the opposite direction to the incident direction of the incident light, relative to the incident surface of the color filter 152.

[0172] With the configuration shown in the left part of Figure 20, the relative sensitivity characteristics of the image sensor 132N are such that, as shown in the right part of Figure 20, the Gr and Gb curves of the image sensor 132N shown by the solid lines gradually decrease with changes in the angle of incidence compared to the Gr and Gb curves of the image sensor 132 shown by the dotted lines, making it possible to widen the high sensitivity range where the angle of incidence is close to 0 degrees.

[0173] Furthermore, the R and B of the image sensor 132N shown by the solid line have lower sensitivity characteristics than the R and B of the image sensor 132 shown by the dotted line in a range greater than a predetermined angle of incidence, thereby suppressing crosstalk.

[0174] In other words, the high sensitivity range where the angle of incidence is close to 0 degrees can be controlled by using a configuration in which OCL 151 is removed, as in image sensor 132N in Figure 20, or a configuration in which OCL 151 is provided, as in image sensor 132 in Figure 6.

[0175] <<16. Fifteenth Embodiment>> <Configuration Example (15) of Image Sensor According to the Present Disclosure>> In the above, an example has been described in which crosstalk is suppressed by the inter-pixel light shielding portion 201. However, it is also possible to reduce the influence of strong, obliquely incident light with a large, unexpected angle of incidence by forming an absorbing member such as an ND filter or an AR-coated material to which an AR coating is applied in front of the low-curvature OCL 151A.

[0176] FIG. 21 shows an example of the configuration of an image sensor 132O in which the color filter 152 is removed and an absorbing member 211 is formed in front of the OCL 151A, as compared to the image sensor 132A in FIG.

[0177] The absorbing member 211 is made of a light absorbing member such as an ND (Neutral Density) filter, and can reduce sensitivity by increasing the optical path length due to oblique incident light, thereby making it possible to reduce the effects of oblique incident light with strong light intensity from an unexpectedly large incident angle.

[0178] 22 shows an example of the configuration of an image sensor 132P in which the color filter 152 is removed and an AR (Anti-Reflection) coating material 221 is formed in front of the OCL 151A, as compared to the image sensor 132A in FIG.

[0179] The AR coating material 221 is an anti-reflection film, and functions as a reflection-enhancing film due to the change in optical path length caused by obliquely incident light, thereby making it possible to reduce the effects of obliquely incident light with strong light intensity from an unexpectedly large incident angle.

[0180] In the fifteenth embodiment of the lensless camera 111 of the present disclosure, the imaging element 132 is replaced with an imaging element 132O or 132P.

[0181] In other words, the degree to which the influence of strong, obliquely incident light from an unexpectedly large angle of incidence is reduced can be controlled (adjusted) by using a configuration in which an absorbing member 211 or an AR coating material 221 is provided, as in the image sensor 132O, 132P in FIGS. 22 and 23, or a configuration in which an absorbing member 211 or an AR coating material 221 is not provided, as in the image sensor 132 in FIG. 6.

[0182] Furthermore, the embodiments of the present disclosure are not limited to the above-described embodiments, and various modifications are possible within the scope of the gist of the present disclosure.

[0183] The present disclosure can also be configured as follows.

[0184] <1> A photodetector including: an optical modulation element that modulates incident light to generate modulated light; and an imaging element that captures a modulated image based on the modulated light, wherein the imaging element has a high sensitivity range control structure that controls a high sensitivity range in which the incident angle of the incident light is near 0 degrees. <2> The photodetector described in <1>, wherein the imaging element includes an on-chip lens that focuses the modulated light, and the high sensitivity range control structure controls the high sensitivity range by a principal curvature of the on-chip lens. <3> The photodetector described in <2>, wherein the principal curvature of the on-chip lens satisfies the following condition: 0≦pixel pitch of the imaging element×principal curvature of the on-chip lens≦2. <4> The photodetector described in <1>, wherein the imaging element includes a photoelectric conversion element that generates, for each pixel, an electric charge according to the amount of incident light, and wherein the high sensitivity range control structure controls the high sensitivity range by an inter-pixel light guiding structure that is made of a material having a lower refractive index than its surroundings and separates the pixels, located upstream of the photoelectric conversion element with respect to the direction of incidence of the incident light. <5> The photodetector according to <1>, wherein the imaging element includes a photoelectric conversion element that generates, for each pixel, an electric charge according to the amount of incident light, and the high sensitivity range control structure controls the high sensitivity range depending on the presence or absence of a filter that optically transmits a predetermined band of the incident light for each pixel. <6> The photodetector according to <1>, wherein the imaging element includes a photoelectric conversion element that generates, for each pixel, an electric charge according to the amount of incident light, and the high sensitivity range control structure controls the high sensitivity range depending on the presence or absence of an on-chip lens that optically focuses the incident light for each pixel. <7> A photodetector including: an optical modulation element that modulates incident light to generate modulated light; and an imaging element that captures a modulated image based on the modulated light, wherein the imaging element has a sensitivity control structure that controls the sensitivity of the incident light when the angle of incidence is around 90 degrees. <8> The photodetector according to <7>, wherein the imaging element includes a photoelectric conversion element that generates, for each pixel, an electric charge according to the amount of incident light, and an inter-pixel separation unit that optically separates the pixels, and the sensitivity control structure controls the sensitivity of the incident light when the incident angle is near 90 degrees depending on the height of the inter-pixel separation unit with respect to the incident direction of the incident light.<9> The photodetector according to <8>, wherein the height of the inter-pixel separator in the incident direction of the incident light satisfies the following condition: 0.3≦height in the incident direction of the incident light / pixel pitch of the image sensor≦3. <10> The photodetector according to <8>, wherein the inter-pixel separator optically separates the pixels upstream of the photoelectric conversion element with respect to the incident direction of the incident light. <11> The photodetector according to <8>, wherein the inter-pixel separator is made of a light-shielding member. <12> The photodetector according to <7>, wherein the image sensor includes a photoelectric conversion element that generates, for each pixel, a charge according to the amount of the incident light, and the sensitivity control structure controls the sensitivity to the incident light when the angle of incidence is near 90 degrees by an aperture structure that narrows the incident light for each pixel. <13> The photodetector according to <7>, wherein the imaging element includes a photoelectric conversion element that generates, in pixel units, an electric charge corresponding to the amount of incident light, and the sensitivity control structure controls the sensitivity to incident light with an incident angle of approximately 90 degrees depending on the height, in the incident direction of the incident light, of an upper layer portion made of an optical member formed before the incident surface of the photoelectric conversion element. <14> The photodetector according to <13>, wherein the height of the upper layer portion satisfies the following relationship: 0<height of the upper layer portion / pixel pitch of the imaging element≦0.7. <15> The photodetector according to <7>, wherein the sensitivity control structure controls the sensitivity to incident light with an incident angle of approximately 90 degrees depending on the presence or absence of an optical absorption material or an AR coating material subsequent to the optical modulation element and preceding the imaging element. <16> A photodetector including: an optical modulation element that modulates incident light to generate modulated light; and an imaging element that captures a modulated image based on the modulated light, wherein the imaging element includes a color mixing adjustment structure that adjusts the degree of color mixing. <17> The photodetector according to <16>, wherein the imaging element includes a photoelectric conversion element that generates, for each pixel, an electric charge according to the amount of incident light, and an inter-pixel separator that optically separates the pixels, and the color mixing adjustment structure adjusts the degree of color mixing depending on a height of the inter-pixel separator that optically separates the pixels in the incident direction of the incident light.<18> The photodetector according to <17>, wherein the inter-pixel separator optically separates the pixels within the photoelectric conversion element. <19> The photodetector according to <17>, wherein the inter-pixel separator is configured to protrude from the light receiving surface of the image sensor in a direction opposite to the direction of incidence of the incident light, upstream of the light receiving surface of the photoelectric conversion element, and optically separates the pixels upstream of the light receiving surface of the image sensor. <20> The photodetector according to <17>, wherein the color mixing adjustment structure adjusts the degree of color mixing depending on the presence or absence of an on-chip lens that optically focuses the incident light on a pixel-by-pixel basis.

[0185] REFERENCE SIGNS LIST 111 Imaging device, 131 Optical modulation element, 132, 132A to 132P Imaging element, 133 Signal processing unit, 134 Output unit, 151, 151A to 151D OCL, 152 Color filter, 153 Inter-pixel light shielding unit, 154 PD, 161, 171 Inter-pixel light shielding unit, 181 Aperture structure, 191, 201 Inter-pixel light guide structure, 211 Absorption member, 221 AR coating material

Claims

1. A photodetector comprising: an optical modulation element that modulates incident light to generate modulated light; and an imaging element that captures a modulated image based on the modulated light, wherein the imaging element is equipped with a high sensitivity range control structure that controls the high sensitivity range where the incident angle of the incident light is near 0 degrees.

2. The photodetector according to claim 1, wherein the imaging element includes an on-chip lens that focuses the modulated light, and the high sensitivity range control structure controls the high sensitivity range by the principal curvature of the on-chip lens.

3. The photodetector according to claim 2, wherein the principal curvature of the on-chip lens satisfies the following condition: 0≦pixel pitch of the imaging element×principal curvature of the on-chip lens≦2.

4. The photodetector according to claim 1, wherein the imaging element comprises a photoelectric conversion element that generates an electric charge corresponding to the amount of incident light in units of pixels, and the high sensitivity range control structure controls the high sensitivity range by an inter-pixel light guide structure that is made of a material with a lower refractive index than the surrounding area and separates the pixels in front of the photoelectric conversion element in the direction of incidence of the incident light.

5. The photodetector according to claim 1, wherein the imaging element comprises a photoelectric conversion element that generates an electric charge corresponding to the amount of incident light in units of pixels, and the high sensitivity range control structure controls the high sensitivity range depending on the presence or absence of a filter that transmits a predetermined optical band of the incident light in units of pixels.

6. The photodetector according to claim 1, wherein the imaging element comprises a photoelectric conversion element that generates an electric charge corresponding to the amount of incident light in units of pixels, and the high sensitivity range control structure controls the high sensitivity range depending on the presence or absence of an on-chip lens that optically focuses the incident light in units of pixels.

7. A photodetector comprising: an optical modulation element that modulates incident light to generate modulated light; and an imaging element that captures a modulated image based on the modulated light, wherein the imaging element has a sensitivity control structure that controls the sensitivity of the incident light when the angle of incidence is close to 90 degrees.

8. The photodetector according to claim 7, wherein the imaging element comprises a photoelectric conversion element that generates an electric charge corresponding to the amount of incident light in units of pixels, and an inter-pixel separation section that optically separates the pixels, and the sensitivity control structure controls the sensitivity to the incident light when the incident angle is near 90 degrees depending on the height of the inter-pixel separation section relative to the incident direction of the incident light.

9. The photodetector according to claim 8, wherein the height of the inter-pixel separation portion in the incident direction of the incident light satisfies the following condition: 0.3≦height in the incident direction of the incident light / pixel pitch of the imaging element≦3.

10. The photodetector according to claim 8, wherein the inter-pixel separator optically separates the pixels in the direction of incidence of the incident light, upstream of the photoelectric conversion element.

11. The photodetector according to claim 8, wherein the inter-pixel separator is made of a light-shielding material.

12. The photodetector according to claim 7, wherein the imaging element comprises a photoelectric conversion element that generates an electric charge corresponding to the amount of incident light in units of pixels, and the sensitivity control structure controls the sensitivity of the incident light when the incident angle is near 90 degrees for each pixel by using an aperture structure that narrows the incident light.

13. The photodetector according to claim 7, wherein the imaging element comprises a photoelectric conversion element that generates an electric charge corresponding to the amount of incident light in units of pixels, and the sensitivity control structure controls the sensitivity of the incident light when the incident angle is near 90 degrees by adjusting the height of an upper layer made of an optical member formed before the incident surface of the photoelectric conversion element in the incident direction of the incident light.

14. The photodetector according to claim 13, wherein the height of the upper layer portion satisfies the relationship of the following formula: 0<height of the upper layer portion / pixel pitch of the imaging element≦0.

7.

15. The optical detection device according to claim 7, wherein the sensitivity control structure controls the sensitivity of the incident light having an incident angle of about 90 degrees depending on the presence or absence of an optical absorbing material or an AR coating material in a stage subsequent to the optical modulation element and in a stage preceding the imaging element.

16. A photodetector comprising: an optical modulation element that modulates incident light to generate modulated light; and an imaging element that captures a modulated image based on the modulated light, wherein the imaging element has a color mixing adjustment structure that adjusts the degree of color mixing.

17. The photodetector according to claim 16, wherein the imaging element comprises a photoelectric conversion element that generates an electric charge corresponding to the amount of incident light for each pixel, and an inter-pixel separation section that optically separates the pixels, and the color mixing adjustment structure adjusts the degree of color mixing by adjusting the height of the inter-pixel separation section that optically separates the pixels in the direction of incidence of the incident light.

18. The photodetector according to claim 17, wherein the inter-pixel isolation section optically isolates the pixels within the photoelectric conversion element.

19. The photodetector device of claim 17, wherein the inter-pixel separation section is configured to protrude from the light receiving surface of the image sensor in a direction opposite to the incident direction of the incident light, upstream of the light receiving surface of the photoelectric conversion element, and optically separates the pixels upstream of the light receiving surface of the image sensor.

20. The photodetector according to claim 17, wherein the color mixing adjustment structure adjusts the degree of color mixing depending on the presence or absence of an on-chip lens that optically focuses the incident light on each pixel.

Images