WO2013065226A1 - 固体撮像素子、撮像装置および信号処理方法 - Google Patents
固体撮像素子、撮像装置および信号処理方法 Download PDFInfo
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- H01L27/14—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate including semiconductor components sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation
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Definitions
- This application relates to a technology for increasing the sensitivity and color of a solid-state imaging device.
- image sensors In recent years, there has been a remarkable increase in functionality and performance of digital cameras and digital movies using solid-state image sensors such as CCDs and CMOSs (hereinafter sometimes referred to as “image sensors”). In particular, due to rapid progress in semiconductor manufacturing technology, the pixel structure in an image sensor has been miniaturized. As a result, the pixels of the image sensor and the drive circuit are highly integrated, and the performance of the image sensor is increasing. In particular, in recent years, a camera using a backside illumination type image sensor that receives light on the back surface side rather than the surface (front surface) side on which the wiring layer of the solid-state image sensor is formed has been developed, and its characteristics are attracting attention. ing. On the other hand, with the increase in the number of pixels of the image sensor, the amount of light received by one pixel is reduced, which causes a problem that the camera sensitivity is reduced.
- ⁇ The sensitivity of the camera is reduced due to the use of color filters for color separation in addition to the increase in the number of pixels.
- a subtractive color filter using an organic pigment as a coloring matter is arranged facing each photosensitive cell of the image sensor. Since the color filter absorbs light other than the color component to be used, when such a color filter is used, the light utilization rate of the camera is lowered.
- each color filter of R, G, B is Only the R, G, B light is transmitted and the remaining light is absorbed. Therefore, the light used in the color camera with the Bayer array is about 1/3 of the entire incident light.
- Japanese Patent Application Laid-Open No. H10-228561 discloses a technique for increasing the amount of received light by attaching a microlens array to the light receiving portion of the image sensor in order to capture much incident light.
- the light aperture ratio in the image sensor can be substantially improved by condensing the light sensing cell using the microlens.
- This technique is currently used in most solid-state image sensors. If this technique is used, the substantial aperture ratio is certainly improved, but it does not solve the problem of a decrease in the light utilization rate due to the color filter.
- Patent Document 2 discloses a technique for making maximum use of light by combining a multilayer color filter (dichroic mirror) and a microlens.
- a multilayer color filter dichroic mirror
- a microlens a plurality of dichroic mirrors that selectively transmit light in a specific wavelength region and reflect light in other wavelength regions without absorbing light are used.
- FIG. 10 is a diagram schematically showing a cross section in a direction perpendicular to the imaging surface of the imaging device disclosed in Patent Document 2.
- the imaging device includes condensing microlenses 4a and 4b, a light shielding unit 20, photosensitive cells 2a, 2b, and 2c, and dichroic mirrors 17, 18, and 19 disposed on and inside the imaging device, respectively. It has.
- the dichroic mirrors 17, 18, and 19 are disposed so as to face the photosensitive cells 2a, 2b, and 2c, respectively.
- the dichroic mirror 17 has characteristics of transmitting R light and reflecting G light and B light.
- the dichroic mirror 18 has a characteristic of reflecting G light and transmitting R light and B light.
- the dichroic mirror 19 has characteristics of reflecting B light and transmitting R light and G light.
- the light incident on the microlens 4 a is incident on the first dichroic mirror 17 after the light flux is adjusted by the microlens 4 b.
- the first dichroic mirror 17 transmits R light but reflects G light and B light.
- the light transmitted through the first dichroic mirror 17 is incident on the photosensitive cell 2a.
- the G light and B light reflected by the first dichroic mirror 17 are incident on the adjacent second dichroic mirror 18.
- the second dichroic mirror 18 reflects G light out of incident light and transmits B light.
- the G light reflected by the second dichroic mirror 18 enters the photosensitive cell 2b.
- the B light transmitted through the second dichroic mirror 18 is reflected by the third dichroic mirror 19 and is incident on the photosensitive cell 2c immediately below it.
- Patent Document 3 discloses an image sensor that can prevent light loss by using a microprism.
- This imaging device has a structure in which different photosensitive cells receive light separated into red, green, and blue by a microprism. Such an image sensor can also prevent light loss.
- Patent Document 2 and Patent Document 3 it is necessary to provide as many photosensitive cells as the number of dichroic mirrors to be used or the number of spectrums. For example, in order to detect light of three colors of RGB, there is a problem that the number of photosensitive cells must be increased by a factor of three compared to the number of photosensitive cells when a conventional color filter is used.
- Patent Document 4 discloses a technique for increasing the utilization factor of light using a dichroic mirror and reflection.
- FIG. 11 shows a part of a cross-sectional view of an image sensor using the technique.
- dichroic mirrors 22 and 23 are disposed in a translucent resin 21.
- the dichroic mirror 22 has characteristics of transmitting G light and reflecting R light and B light.
- the dichroic mirror 23 has characteristics of transmitting R light and reflecting G light and B light.
- R light and G light can all be detected by the following principle.
- the R light is reflected by the dichroic mirror 22 and transmitted by the dichroic mirror 23.
- the R light reflected by the dichroic mirror 22 is further reflected at the interface between the translucent resin 21 and air and enters the dichroic mirror 23.
- the R light passes through the dichroic mirror 23, and further passes through the organic dye filter 25 and the microlens 26 having R light transmittance. In this way, although part of the light is reflected by the metal layer 27, most of the R light incident on the dichroic mirrors 22 and 23 is incident on the light sensing unit.
- the G light when the G light is incident on the dichroic mirrors 22 and 23, the G light is transmitted through the dichroic mirror 22 and reflected by the dichroic mirror 23.
- the G light reflected by the dichroic mirror 23 is further totally reflected at the interface between the translucent resin 21 and air, and enters the dichroic mirror 22.
- the G light passes through the dichroic mirror 22, and further passes through the organic dye filter 24 and the micro lens 26 having G light transmittance. In this way, although part of the light is reflected by the metal layer 27, most of the G light incident on the dichroic mirrors 22 and 23 is incident on the light sensing unit without any loss.
- the technique disclosed in Patent Document 4 can receive two colors with almost no loss, although one color of RGB light is lost. For this reason, it is not necessary to arrange the light sensing units for the three colors RGB.
- the light utilization rate with only the organic dye filter is about 3
- the light utilization factor when using this technique is about 2/3 of the total incident light. That is, according to this technique, the imaging sensitivity is improved about twice. However, even with this technique, one of the three colors is lost.
- Patent Document 5 discloses a colorization technique that increases the light utilization rate without significantly increasing the number of photosensitive cells using a spectral element. According to this technique, light is incident on different photosensitive cells depending on the wavelength range by the spectral elements arranged corresponding to the photosensitive cells. Each photosensitive cell receives light on which components in different wavelength ranges are superimposed from a plurality of spectral elements. As a result, a color signal can be generated by signal calculation using a photoelectric conversion signal output from each photosensitive cell.
- Embodiments of the present invention provide a color imaging technique that can increase the light utilization rate and have good color reproducibility without significantly increasing the number of photosensitive cells.
- a solid-state imaging device includes a first photosensitive cell, a second photosensitive cell, a third photosensitive cell, and a fourth photosensitive cell.
- the light received by each photosensitive cell is the cell incident light of each photosensitive cell, and the visible light included in the cell incident light includes the first color component, the second
- the visible light of the color component which is composed of the color component and the third color component, excluding each color component is used as the complementary color light of the color component
- the spectral element array is incident on the cell of the first photosensitive cell.
- Light obtained by adding light of the first color component to light obtained by removing complementary color light of the first color component from light is incident on the first photosensitive cell, and cell incidence of the second photosensitive cell
- the light obtained by adding the complementary color light of the first color component to the light obtained by removing the light of the first color component from the light is incident on the second photosensitive cell, and is incident on the cell of the third photosensitive cell.
- the light obtained by adding the complementary color light of the third color component to the light obtained by removing the light of the third color component from the light is the third light.
- the solid-state imaging device and the imaging apparatus by using a spectral element that causes incident light to be incident on different photosensitive cells according to color components, it is possible to use light without significantly increasing the number of photosensitive cells.
- the rate is high, and color imaging with higher color reproducibility than before is possible.
- FIG. 1 It is a perspective view which shows typically the arrangement
- FIG. 1 is a top view which shows an example of the unit block of the solid-state image sensor by this invention,
- (b) is AA 'sectional view,
- (c) is BB' sectional view.
- (A) is a figure which shows an example of the pixel array of the image pick-up element in Embodiment 1 of this invention
- (b) is a figure which shows the other example of the pixel array of the image pick-up element in Embodiment 1 of this invention.
- (A) is a top view which shows the basic structure of the image pick-up element in Embodiment 1 of this invention
- (b) is AA 'sectional view
- (c) is BB' sectional view. It is a flowchart which shows the procedure of the color information generation process in Embodiment 1 of this invention.
- (A) is a top view which shows the basic structure of the other image pick-up element in Embodiment 1 of this invention, (b) is AA 'sectional view, (c) is BB' sectional view.
- (A) is a top view which shows the basic structure of the image pick-up element in Embodiment 2 of this invention, (b) is CC 'line sectional drawing, (c) is DD' line sectional drawing. It is sectional drawing of the conventional image pick-up element using a micro lens and a multilayer film filter (dichroic mirror). It is sectional drawing of the conventional image pick-up element using a multilayer filter (dichroic mirror) and reflection.
- a solid-state imaging device includes a plurality of unit blocks each including a first photosensitive cell, a second photosensitive cell, a third photosensitive cell, and a fourth photosensitive cell. Is arranged in a two-dimensional manner, and a spectral element array that is arranged to face the photosensitive cell array and includes a plurality of spectral elements.
- the light received by each photosensitive cell is the cell incident light of each photosensitive cell, and the visible light included in the cell incident light includes the first color component, the second
- the visible light of the color component which is composed of the color component and the third color component, excluding each color component is used as the complementary color light of the color component
- the spectral element array is incident on the cell of the first photosensitive cell.
- Light obtained by adding light of the first color component to light obtained by removing complementary color light of the first color component from light is incident on the first photosensitive cell, and cell incidence of the second photosensitive cell
- the light obtained by adding the complementary color light of the first color component to the light obtained by removing the light of the first color component from the light is incident on the second photosensitive cell, and is incident on the cell of the third photosensitive cell.
- the light obtained by adding the complementary color light of the third color component to the light obtained by removing the light of the third color component from the light is the third light.
- the spectral element array includes a first spectral element arranged to face the first photosensitive cell in each unit block, Opposing to the second light-sensing element disposed opposite to the second light-sensitive cell, facing the third light-sensing element disposed opposite to the third light-sensitive cell, and facing the fourth light-sensitive cell.
- a fourth spectral element arranged in the same manner. The first spectral element causes at least a part of the complementary color light of the first color component to be incident on the second photosensitive cell, and the light of the first color component enters the first photosensitive cell.
- the second spectral element causes at least part of the light of the first color component to enter the first photosensitive cell, and the complementary color light of the first color component is input to the second light.
- the third spectral element causes at least a part of the light of the third color component to enter the fourth photosensitive cell, and the complementary color light of the third color component is incident on the fourth light sensing cell.
- the fourth light-splitting element causes at least a part of the complementary color light of the third color component to be incident on the third light-sensitive cell, so that the light of the third color component is incident on the third light-sensitive cell. Is incident on the fourth photosensitive cell.
- the first spectral element causes half of the complementary color light of the first color component to enter the second photosensitive cell, and The other half of the complementary color light of the first color component is incident on one photosensitive cell included in the adjacent first adjacent unit block, and the second spectral element is configured to emit light of the first color component.
- Half of the light is incident on the first photosensitive cell, and the remaining half of the light of the first color component is incident on one photosensitive cell included in an adjacent second adjacent unit block, and the third
- the spectral element causes the half of the light of the third color component to enter the fourth photosensitive cell, and the other half of the light of the third color component is adjacent to the first and second adjacent units.
- the light is incident on one photosensitive cell included in one of the blocks, and the fourth spectral element is Half of the complementary color light of the color component is incident on the third photosensitive cell, and the other half of the complementary color light of the third color component is included in the other of the adjacent first and second adjacent unit blocks. Is incident on one photosensitive cell.
- the first spectral element causes almost all of the complementary color light of the first color component to be incident on the second photosensitive cell
- the second spectral element causes almost all of the light of the first color component to be incident on the first photosensitive cell
- the third spectral element is substantially all of the light of the third color component. Is incident on the fourth photosensitive cell, and the fourth light-splitting element causes substantially all of the complementary color light of the third color component to be incident on the third photosensitive cell.
- the first color component is one of red and blue
- the third color component is The other color component of red and blue.
- the first spectral element, the second spectral element, the third spectral element, and the fourth has a translucent member, the shape of the translucent member, and the refraction of the translucent member and another translucent member having a refractive index lower than that of the translucent member. Spectroscopy using the difference in rate.
- the first spectral element, the second spectral element, the third spectral element, and the fourth Each of the light-splitting elements includes a dichroic mirror, and the light is dispersed by the dichroic mirror.
- An imaging device includes a solid-state imaging device according to any one of items (1) to (7), an optical system that forms an image on the solid-state imaging device, and the solid-state imaging device.
- a signal processing unit that generates color information by calculation using the third photoelectric conversion signal output from the third photosensitive cell and the fourth photoelectric conversion signal output from the fourth photosensitive cell; Is provided.
- the signal processing unit calculates a difference between the first photoelectric conversion signal and the second photoelectric conversion signal, and the third photoelectric conversion.
- a first color signal and a second color signal are generated by calculating a difference between the signal and the fourth photoelectric conversion signal.
- the signal processing unit adds the first and second photoelectric conversion signals, and the third and fourth photoelectric conversion signals. And a luminance signal is generated by an operation including any one of addition of the first to fourth photoelectric conversion signals.
- a signal processing method is a method for processing a signal output from a solid-state imaging device according to any one of items (1) to (7), wherein the first light sensing is performed.
- the method includes a step A for obtaining a fourth photoelectric conversion signal output from the fourth photosensitive cell, and a step B for generating color information using the first to fourth photoelectric conversion signals.
- the step B generates a first difference signal indicating a difference between the first photoelectric conversion signal and the second photoelectric conversion signal. And generating a second difference signal indicating a difference between the third photoelectric conversion signal and the fourth photoelectric conversion signal.
- the step B includes the addition of the first and second photoelectric conversion signals, the addition of the third and fourth photoelectric conversion signals, and the first A step of generating a luminance signal by an operation including any one of addition of the first to fourth photoelectric conversion signals, and the cell incident light using the luminance signal, the first difference signal, and the second difference signal. Generating red, green, and blue color signals included in.
- a solid-state imaging device includes a photosensitive cell array including a plurality of photosensitive cells (pixels) arranged two-dimensionally on an imaging surface, and a spectral element array including a plurality of spectral elements.
- FIG. 1 is a perspective view schematically showing a part of the photosensitive cell array 200 and the spectral element array 100 formed on the imaging surface of the solid-state imaging device 10.
- the spectral element array 100 is disposed on the light incident side facing the photosensitive cell array 200.
- the arrangement, shape, size, and the like of the photosensitive cells 2 are not limited to the example shown in this figure, and may be any known arrangement, shape, and size.
- the spectral element array 100 is represented by a quadrangular prism for convenience, the spectral element array 100 does not actually have such a shape and can have various structures.
- each light sensing cell 2 When each light sensing cell 2 receives light, it outputs an electrical signal (hereinafter referred to as a “photoelectric conversion signal” or a “pixel signal”) corresponding to the intensity of the light received by photoelectric conversion (incident light amount). To do.
- each photosensitive cell 2 receives light in a plurality of wavelength regions (color components) whose traveling directions are changed by the spectral element array 100. As a result, the light received by each photosensitive cell 2 has a spectral distribution (intensity distribution for each wavelength range) different from the light received when it is assumed that there is no spectral element.
- FIG. 2A is a plan view showing an example of a basic pixel configuration (unit block) 40 of the photosensitive cell array 200.
- the photosensitive cell array 200 has a structure in which a plurality of unit blocks 40 each including four photosensitive cells 2a, 2b, 2c, and 2d are two-dimensionally arranged on the imaging surface. In the example shown in the figure, four photosensitive cells are arranged in two rows and two columns in one unit block.
- FIG. 2 (b) and 2 (c) are diagrams schematically showing an AA ′ line cross-section and a BB ′ line cross-section in FIG. 2 (a), respectively.
- 2B and 2C the traveling direction changes depending on the color component when light incident on the image sensor 10 passes through the spectral element array 100, and as a result, the spectral distribution of the light received by each photosensitive cell is shown. It shows that they are different from each other.
- the spectral element array 1 does not exist, the light received by each photosensitive cell is referred to as “cell incident light” of the photosensitive cell.
- the photosensitive cells 2a to 2d included in one unit block are close to each other, it can be considered that the light intensity and the spectral distribution included in the cell incident light of the photosensitive cells are almost the same.
- the intensity of the visible light component of the cell incident light of these photosensitive cells is represented by the symbol “W”.
- the visible light color component excluding each color component is referred to as “complementary color” of the color component
- the complementary color light is referred to as “complementary color light”.
- the complementary color of the first color component C1 is represented by C2 + C3
- the complementary color of the second color component C2 is represented by C1 + C3
- the complementary color of the third color component C3 is represented by C1 + C2.
- the complementary color of the color component Cn (Cn is any one of C1, C2, and C3) and its intensity may be represented by Cn ⁇ .
- the combination of the first to third color components is typically a combination of three primary colors of red (R), green (G), and blue (B), but divides visible light into three wavelength ranges. Any other combination of color components may be used.
- the spectral element array 100 is obtained by removing the first color component light (intensity C1) from the light obtained by removing the complementary color light (intensity C1 ⁇ ) of the first color component from the cell incident light (intensity W) of the first photosensitive cell 2a. ) Is added to the first photosensitive cell 2a. Further, the complementary color light (intensity C1 ⁇ ) of the first color component is added to the light obtained by removing the light (intensity C1) of the first color component from the cell incident light (intensity W) of the second photosensitive cell 2b. Light is incident on the second photosensitive cell 2b.
- complementary color light (intensity C3 ⁇ ) of the third color component was added to light obtained by removing light of the third color component (intensity C3) from the cell incident light (intensity W) of the third photosensitive cell 2c. Light is incident on the third photosensitive cell 2c. Further, the light of the third color component (intensity C3) is added to the light obtained by removing the complementary color light (intensity C3 ⁇ ) of the third color component from the cell incident light (intensity W) of the fourth photosensitive cell 2d. Light is incident on the fourth photosensitive cell 2d.
- the photosensitive cells 2a to 2d are respectively W-C1 ⁇ + C1, W-C1 + C1 ⁇ , W-C3 + C3 ⁇ , and W-C3 ⁇ + C3, as shown in FIGS. Receives light of the indicated intensity. Each photosensitive cell outputs a photoelectric conversion signal (pixel signal) corresponding to these intensities.
- S2a to S2d can be expressed by the following formulas 1 to 4, respectively.
- D1 and D2 are expressed by the following formulas 5 and 6, respectively.
- the RGB signal can be obtained by matrix operation. That is, the color signal can be calculated by signal calculation based on the four photoelectric conversion signals S2a to S2d output from the photosensitive cells 2a to 2d.
- color information can be obtained by signal calculation using a spectral element without using a color filter that absorbs part of light. Therefore, loss of light can be prevented and imaging sensitivity can be increased.
- the spectral element array 100 is depicted as a continuous element covering a plurality of photosensitive cells, but the spectral element array 4 is spatially separated. It may be an aggregate of a plurality of spectral elements. As such a spectral element, for example, a high refractive index transparent member, a dichroic mirror, a microprism, etc., which will be described later, can be used.
- the spectral element array 100 in the present embodiment may be configured in any way as long as the photoelectric conversion signals represented by the above formulas 1 to 4 can be obtained.
- the spectral element array 100 may perform spectroscopy using a hologram element or the like. .
- FIG. 3 is a block diagram illustrating the overall configuration of the imaging apparatus according to the first embodiment.
- the imaging apparatus according to the present embodiment is a digital electronic camera, and includes an imaging unit 300 and a signal processing unit 400 that generates a signal (image signal) indicating an image based on a signal transmitted from the imaging unit 300. ing. Note that the imaging device may generate only a still image or may have a function of generating a moving image.
- the imaging unit 300 is an optical lens 12 for imaging a subject, an optical filter 11, and a solid-state imaging device 10 (converting optical information imaged through the optical lens 12 and the optical filter 11 into an electrical signal by photoelectric conversion ( Image sensor).
- the imaging unit 300 further generates a basic signal for driving the imaging device 10, receives an output signal from the imaging device 10, and sends it to the signal processing unit 400, and signal generation / reception.
- an element driving unit 14 that drives the image sensor 10 based on the basic signal generated by the unit 13.
- the optical lens 12 is a known lens and may be a lens unit having a plurality of lenses.
- the optical filter 11 is a combination of a quartz low-pass filter for reducing moire patterns generated due to pixel arrangement and an infrared cut filter for removing infrared rays.
- the image sensor 10 is typically a CMOS or a CCD, and is manufactured by a known semiconductor manufacturing technique.
- the signal generation / reception unit 13 and the element driving unit 14 are configured by an LSI such as a CCD driver, for example.
- the signal processing unit 400 generates an image signal by processing a signal transmitted from the imaging unit 300, a memory 30 for storing various data generated in the process of generating the image signal, and the generated signal And an image signal output unit 16 for sending the image signal to the outside.
- the image signal generation unit 15 can be suitably realized by a combination of hardware such as a known digital signal processor (DSP) and software that executes image processing including image signal generation processing.
- the memory 30 is configured by a DRAM or the like. The memory 30 records the signal transmitted from the imaging unit 300 and temporarily records the image data generated by the image signal generation unit 15 and the compressed image data. These image data are sent to a recording medium (not shown) or a display unit via the image signal output unit 16.
- the imaging apparatus may include known components such as an electronic shutter, a viewfinder, a power source (battery), and a flashlight, but a description thereof is omitted because it is not particularly necessary for understanding the present embodiment.
- the above configuration is merely an example, and in the present embodiment, publicly known elements can be appropriately combined and used for the constituent elements other than the image sensor 10 and the image signal generation unit 15.
- FIG. 4 is a diagram schematically illustrating a state in which light transmitted through the lens 12 is incident on the image sensor 10 during exposure.
- the lens 12 can be generally composed of a plurality of lenses arranged in the optical axis direction, but is drawn as a single lens for simplicity.
- a photosensitive cell array including a plurality of photosensitive cells (pixels) arranged two-dimensionally is disposed on the imaging surface 10a of the imaging element 10. Each photosensitive cell is typically a photodiode, and outputs a photoelectric conversion signal (pixel signal) corresponding to the amount of incident light by photoelectric conversion.
- Light (visible light) transmitted through the lens 12 and the optical filter 11 is incident on the imaging surface 10a.
- the intensity of light incident on the imaging surface 10a and the distribution (spectral distribution) of the amount of incident light for each wavelength range differ depending on the incident position.
- FIGS. 5A and 5B are plan views showing an example of a pixel array in the present embodiment.
- the photosensitive cell array 200 includes a plurality of photosensitive cells arranged in a square lattice pattern on the imaging surface 10a as shown in FIG.
- the photosensitive cell array 200 includes a plurality of unit blocks 40, and each unit block 40 includes four photosensitive cells 2a, 2b, 2c, and 2d.
- the arrangement of the photosensitive cells is not such a square lattice arrangement, and may be, for example, an oblique arrangement shown in FIG. 4B or another arrangement.
- the four photosensitive cells 2a to 2d included in each unit block are close to each other as shown in FIGS. 5 (a) and 5 (b). It is possible to obtain color information by appropriately configuring the spectral element array.
- Each unit block may include five or more photosensitive cells.
- a spectral element array including a plurality of spectral elements is disposed on the light incident side facing the photosensitive cell array 200.
- one spectral element is provided for each of the four photosensitive cells included in each unit block.
- the spectroscopic element in the present embodiment is an optical element that directs incident light in different directions according to the wavelength range by using diffraction of light generated at the boundary between two types of translucent members having different refractive indexes.
- This type of spectroscopic element consists of a high refractive index transparent member (core part) formed of a material having a relatively high refractive index and a low contact with each side surface of the core part formed of a material having a relatively low refractive index. And a refractive index transparent member (cladding portion). Due to the difference in refractive index between the core part and the clad part, a phase difference occurs between the light transmitted through the core part and diffraction occurs.
- a high refractive index transparent member may be referred to as a “spectral element” because spectroscopy is possible due to a difference in refractive index between the core portion and the cladding portion. Details of such a diffractive spectral element are disclosed in, for example, Japanese Patent No. 4264465.
- the spectral element array having the spectral elements as described above can be manufactured by performing thin film deposition and patterning by a known semiconductor manufacturing technique.
- the material (refractive index), shape, size, arrangement pattern, and the like of the spectral elements it becomes possible to separate and integrate light in a desired wavelength range into individual photosensitive cells.
- a signal corresponding to a necessary color component can be calculated from a set of photoelectric conversion signals output from each photosensitive cell.
- FIG. 6A is a plan view showing the basic structure of the image sensor 10.
- the spectroscopic elements 1a, 1b, 1c, and 1d are disposed to face the four photosensitive cells 2a, 2b, 2c, and 2d, respectively.
- a plurality of patterns having such a basic structure are repeatedly formed on the imaging surface 10a.
- the imaging device 10 includes a semiconductor substrate 7 made of a material such as silicon, photosensitive cells 2a to 2d arranged inside the semiconductor substrate 7, and a surface side of the semiconductor substrate 7 (light is incident thereon).
- microlenses 4a for efficiently condensing light to each photosensitive cell are arranged corresponding to the individual photosensitive cells with a transparent layer 6a interposed therebetween. Even if the microlens 4a is not arranged, it is possible to obtain the effect of the present embodiment.
- the imaging element 10 shown in FIGS. 6A to 6C can be manufactured by a known semiconductor manufacturing technique.
- the imaging element 10 shown in FIGS. 6A to 6C has a surface irradiation type structure in which light enters each photosensitive cell from the wiring layer 5 side.
- the imaging device 10 of the present embodiment is not limited to such a structure, and may have a back-illuminated structure that receives light from the opposite side of the wiring layer 5.
- the spectral elements 1a and 1b have a rectangular cross section that is long in the light transmitting direction, and spectrally separate by the difference in refractive index between itself and the transparent layer 6a.
- the spectral element 1a makes red (R) light incident on the opposing photosensitive cell 2a, and halves cyan (Cy) light into the photosensitive cell 2b and photosensitive cells (not shown) included in adjacent unit blocks. Make it incident.
- cyan (Cy) light is light composed of green (G) light and blue (B) light.
- the spectroscopic element 1b causes Cy light to enter the opposing photosensitive cell 2b, and causes R light to be incident in half on the photosensitive cell 2a and on photosensitive cells (not shown) included in other adjacent unit blocks.
- the length and thickness of the spectral elements 1a and 1b are designed so that the spectral elements 1a and 1b have the spectral characteristics described above.
- Cy light is not necessarily light which makes the cyan color which is a mixed color of green and blue visually recognized. For example, when the cell incident light does not include B light at all, the Cy light is light that makes green visible as in the G light.
- the photosensitive cell 2a receives R light from the spectral element 1a, and also receives R light by half from the spectral element 1b and the spectral elements included in the adjacent unit block.
- the photosensitive cell 2b receives Cy light from the spectral element 1b, and also receives Cy light by half from the spectral element 1a and spectral elements (not shown) included in adjacent unit blocks.
- the spectroscopic elements 1c and 1d also have a rectangular cross section that is long in the direction in which light is transmitted, and spectrally separate by the difference in refractive index between itself and the transparent layer 6a.
- the light-splitting element 1c makes yellow light (Ye) incident on the opposing photosensitive cell 2c, and divides blue (B) light by half into the photosensitive cell 2d and the photosensitive cell (not shown) included in the adjacent unit block. Make it incident.
- yellow light (Ye) is light composed of red (R) light and green (G) light.
- the spectroscopic element 1d causes blue (B) light to enter the opposing photosensitive cell 2d, and yellow (Ye) is applied to the photosensitive cell 2c and the photosensitive cells (not shown) included in other adjacent unit blocks.
- Light is incident half by one.
- the length and thickness of the spectral elements 1c and 1d are designed so that the spectral elements 1c and 1d have the spectral characteristics described above.
- Ye light is not necessarily light which visually recognizes yellow which is a mixed color of red and green. For example, when the cell incident light does not include G light at all, Ye light is light that causes red to be visually recognized, like R light.
- the photosensitive cells 2a to 2d output photoelectric conversion signals S2a to S2d represented by the following equations 12 to 15, respectively.
- signals corresponding to the intensities of red light, green light, and blue light are respectively represented by Rs, Gs, and Bs.
- a signal Cs corresponding to the intensity of cyan light is Gs + Bs
- a signal Ys corresponding to the intensity of yellow light is Rs + Gs
- a signal Ws corresponding to the intensity of white light is Rs + Gs + Bs.
- Equations 12 to 15 correspond to those obtained by substituting C1s for Rs, C1 ⁇ s for Cs, C3s for Bs, and C3 ⁇ s for Ys in Equations 1 to 4, respectively. That is, in the present embodiment, the first color component is R light, the second color component is G light, and the third color component is B light.
- the image signal generation unit 15 (FIG. 3) generates color information by a calculation using the photoelectric conversion signals represented by equations 12 to 15.
- color information generation processing by the image signal generation unit 15 will be described with reference to FIG.
- FIG. 7 is a flowchart showing the procedure of color information generation processing in the present embodiment.
- an RGB color signal is obtained from the two color difference signals and one luminance signal by matrix calculation. Specifically, 4Rs is generated by adding 1/2 of the luminance signal to the color difference signal (4Rs-2Ws), and 4Bs is generated by adding 1/2 of the luminance signal to the color difference signal (4Bs-2Ws). 4Gs is obtained by subtracting 4Rs and 4Bs from.
- the image signal generation unit 15 executes the above signal calculation for each unit block 40 of the photosensitive cell array 2 to thereby generate a signal (referred to as a “color image signal”) indicating an image of each color component of R, G, and B. Generate.
- the generated color image signal is output to a recording medium (not shown) or a display unit by the image signal output unit 16.
- a color image signal can be obtained by the addition / subtraction process using the photoelectric conversion signals S2a to S2d.
- the imaging device 10 in the present embodiment since an optical element that absorbs light is not used, light loss can be significantly reduced as compared with the conventional technology using a color filter or the like.
- the spectral element array having a basic configuration of 2 rows and 2 columns is arranged facing the photosensitive cell array.
- a spectral element 1a that divides light into red light and non-red light is arranged.
- a spectral element 1b for separating light into cyan light and non-cyan light is arranged.
- a spectral element 1c that divides light into yellow light and non-yellow light is arranged.
- a spectral element 1d that divides light into blue light and non-blue light is arranged.
- the four photoelectric conversion signals obtained are: It is always a combination of four signals represented by equations 12-15. That is, by performing the above signal calculation while shifting the pixel block to be calculated one row and one column at a time, it is possible to obtain information on each RGB color component by the number of pixels. This means that the resolution of the imaging device can be increased to the number of pixels. Therefore, the imaging apparatus of the present embodiment can generate a high-resolution color image in addition to higher sensitivity than the conventional imaging apparatus.
- the image signal generation unit 15 does not necessarily generate all the image signals of the three color components. It may be configured to generate only one or two color image signals depending on the application. Further, signal amplification, synthesis, and correction may be performed as necessary.
- each spectral element has the above-described spectral performance strictly, but their spectral performance may be slightly shifted. That is, the photoelectric conversion signal actually output from each photosensitive cell may be slightly deviated from the photoelectric conversion signals shown in equations 12-15. Even when the spectral performance of each spectral element deviates from the ideal performance, good color information can be obtained by correcting the signal according to the degree of deviation.
- the signal calculation performed by the image signal generation unit 15 in the present embodiment can be executed not by the imaging apparatus itself but by another device.
- the color information can also be generated by causing an external device that has received an input of the photoelectric conversion signal output from the image sensor 10 to execute a program that defines the signal calculation processing in the present embodiment.
- the basic structure of the image sensor 10 is not limited to the configuration shown in FIG.
- the effect of this embodiment is not changed even if the spectral element 1a and the spectral element 1b are interchanged or the spectral element 1c and the spectral element 1d are interchanged.
- the arrangement of the first row and the arrangement of the second row shown in FIG. 6A may be interchanged, and the spectral elements 1a and 1b and the spectral elements 1c and 1d are arranged in the column direction instead of the row direction. Even if it is arranged like this, its effectiveness does not change.
- Any configuration may be used as long as it is configured as described above.
- the spectral element in the present embodiment emits light of a desired color component to each photosensitive cell. Any type of incident light can be used.
- a microprism or a dichroic mirror may be used as the spectral element. It is also possible to use different types of spectral elements in combination.
- FIG. 8 shows a configuration example of an image sensor that partially uses light transmission and reflection by a dichroic mirror.
- FIG. 8A is a plan view showing a basic pixel configuration in this example.
- FIGS. 8B and 8C are views showing the AA ′ line cross section and the BB ′ line cross section in FIG. 8A, respectively.
- spectral elements 1e and 1f including dichroic mirrors are arranged instead of the spectral elements 1a and 1b shown in FIG.
- the spectral elements 1c and 1d have the same characteristics as the spectral elements 1c and 1d shown in FIG.
- the imaging element 10 shown in FIG. 8 has a back-illuminated structure in which light enters from the opposite side of the wiring layer 5, but this is not particularly important, and has a front-illuminated structure. It may be.
- the image pickup device 10 includes a semiconductor substrate 7 made of a material such as silicon, photosensitive cells 2a to 2d arranged in the semiconductor substrate 7, and A transparent layer 6b formed on the back side (light incident side), and spectral elements 1e and 1f and spectral elements 1c and 1d arranged inside the transparent layer 6b are provided.
- a wiring layer 5 is formed on the surface side of the semiconductor substrate 7 (the side opposite to the light incident side).
- a fixed base 9 that supports the semiconductor substrate 7, the wiring layer 5, and the like is disposed on the surface side. The fixed substrate 9 is bonded to the semiconductor substrate 7 through the transparent layer 6b.
- the transparent layer 6b is formed of a translucent member having a higher refractive index than air and a lower refractive index than the spectral elements 1c and 1d.
- the spectroscopic element 1e includes a combination of two dichroic mirrors that reflect Cy light and transmit light other than Cy light.
- the spectral element 1f includes a combination of two dichroic mirrors that reflect R light and transmit light other than R light.
- the two dichroic mirrors included in each spectral element are arranged so as to be symmetrically inclined with respect to the normal line of the imaging surface. The inclination angles of these dichroic mirrors are set so that the reflected light is totally reflected at the interface with the air layer outside the image sensor 10 and enters two pixels adjacent to the opposing pixel.
- the R light When light enters the spectral element 1f, the R light is reflected and the Cy light is transmitted. Half of the reflected R light is totally reflected at the interface between the transparent layer 6b and air and enters the photosensitive cell 2a. The remaining half of the reflected R light is totally reflected at the interface between the transparent layer 6b and air, and enters the photosensitive cell included in another adjacent unit block. The Cy light transmitted through the spectral element 1f enters the photosensitive cell 2a.
- the spectroscopic element 1 c causes Ye light to be incident on the photosensitive cell 2 c and B light is incident on the photosensitive cell included in the unit block adjacent to the photosensitive cell 2 d.
- the B light is incident on the photosensitive cell 2d
- the Ye light is incident on the photosensitive cell included in the unit block adjacent to the photosensitive cell 2c.
- the sizes and shapes of the spectral elements 1c and 1d are designed in consideration of refraction at the interface between the transparent layer 6b and the semiconductor substrate 7.
- each of the photosensitive cells 2a to 2d receives the same light as when the configuration shown in FIG. 6 is adopted. Therefore, the photoelectric conversion signal output from each of the photosensitive cells 2a to 2d is not different from the photoelectric conversion signal in the configuration of FIG. 6, and the above signal calculation can be applied as it is. Thus, even if the configuration shown in FIG. 8 is adopted, the same effect as that obtained when the configuration shown in FIG. 6 is adopted can be obtained.
- the imaging apparatus according to the present embodiment is different from the imaging apparatus according to the first embodiment only in the structure of the imaging element 10, and the other components are the same. The following description will be focused on the differences from the imaging apparatus of the first embodiment, and the description of overlapping points will be omitted.
- the image sensor 10 in the present embodiment is not a spectral element using diffraction, but includes a dichroic mirror that separates light into primary and complementary colors.
- each spectral element in the present embodiment does not allow light to be incident on the photosensitive cell in the adjacent unit block, but allows light to be incident only on the photosensitive cell in each unit block.
- the basic structure of the image sensor 10 in the present embodiment will be described.
- FIG. 9 is a diagram showing a basic structure of the image sensor 10 in the present embodiment.
- the image sensor 10 in the present embodiment is a back-illuminated image sensor. Also in this embodiment, it is not important whether the type of the image sensor 10 is a backside illumination type or a front side illumination type, and the image sensor 10 may be a front side illumination type.
- FIG. 9A is a plan view of the light receiving surface side of the image sensor 10. The arrangement of the photosensitive cells of the imaging device 10 in the present embodiment is the same as that in the first embodiment, and one unit block has four photosensitive cells 2a to 2d.
- Dichroic mirrors 3a, 3b, 3c, and 3d are arranged to be inclined with respect to the imaging surface so as to face the photosensitive cells 2a, 2b, and 2c.
- the inclination angle of the dichroic mirror is set so that the reflected light is totally reflected at the interface with the air layer outside the image sensor 10 and enters the adjacent pixel of the counter pixel.
- FIGS. 9B and 9C are diagrams respectively showing a CC ′ line cross section and a DD ′ line cross section in FIG. 9A.
- the image pickup device 10 includes a semiconductor substrate 7 made of a material such as silicon, photosensitive cells 2a to 2d disposed in the semiconductor substrate 7, and a back surface side of the semiconductor substrate 7 (a light incident side). ) And a dichroic mirror 3a, 3b, 3c, 3d disposed inside the transparent layer 6b.
- a wiring layer 5 is formed on the surface side of the semiconductor substrate 7 (the side opposite to the light incident side).
- a fixed base 9 that supports the semiconductor substrate 7, the wiring layer 5, and the like is disposed on the surface side. The fixed substrate 9 is bonded to the semiconductor substrate 7 through the transparent layer 6b.
- the dichroic mirror 3a has a characteristic of transmitting R light and reflecting Cy light. Further, the dichroic mirror 3b has a characteristic of transmitting Cy light and reflecting R light. As a result, the R light transmitted through the dichroic mirror 3a enters the photosensitive cell 2a. The Cy light reflected by the dichroic mirror 3a is totally reflected at the interface between the transparent layer 6b and air and enters the photosensitive cell 2b. The Cy light transmitted through the dichroic mirror 3b enters the photosensitive cell 2b. The R light reflected by the dichroic mirror 3b is totally reflected at the interface between the transparent layer 6b and air and enters the photosensitive cell 2a.
- the dichroic mirror 3c has a characteristic of transmitting Ye light and reflecting B light. Further, the dichroic mirror 3d has a characteristic of transmitting B light and reflecting Ye light. As a result, the Ye light transmitted through the dichroic mirror 3c enters the photosensitive cell 2c. The B light reflected by the dichroic mirror 3c is totally reflected at the interface between the transparent layer 6b and air and enters the photosensitive cell 2d. The B light transmitted through the dichroic mirror 3d enters the photosensitive cell 2d. The Ye light reflected by the dichroic mirror 3d is totally reflected at the interface between the transparent layer 6b and air and enters the photosensitive cell 2c.
- each of the photosensitive cells 2a to 2d receives light of the same color component as when the configuration in the first embodiment is adopted. That is, the photosensitive cell 2a receives the R light transmitted through the dichroic mirror 3a and the R light reflected by the dichroic mirror 3b.
- the photosensitive cell 2b receives Cy light transmitted through the dichroic mirror 3b and Cy light reflected by the dichroic mirror 3a.
- the photosensitive cell 2c receives Ye light transmitted through the dichroic mirror 3c and Ye light reflected by the dichroic mirror 3d.
- the photosensitive cell 2d receives the B light transmitted through the dichroic mirror 3d and the B light reflected by the dichroic mirror 3c.
- the photoelectric conversion signals S2a to S2d output from the photosensitive cells 2a to 2d can be expressed by equations 12 to 15 as in the case of adopting the configuration in the first embodiment. Therefore, color information can be obtained by the same processing as that in the first embodiment.
- a color image signal can be obtained by signal calculation processing using the photoelectric conversion signals S2a to S2d, as in the imaging device of Embodiment 1.
- the imaging device 10 according to the present embodiment also does not use an optical element that absorbs light, so that the loss of light can be significantly reduced as compared with the conventional technique using a color filter or the like.
- three color signals are obtained by calculation using four photoelectric conversion signals, there is an effect that the amount of color information obtained with respect to the number of pixels is larger than in the case of a conventional image sensor.
- the dichroic mirror 3a that divides light into cyan light and non-cyan light is arranged in the first row and the first column.
- a dichroic mirror 3b that divides light into red light and non-red light is arranged in the first row and the second column.
- a dichroic mirror 3c that divides light into blue light and non-blue light is arranged in the second row and the first column.
- a dichroic mirror 3d that divides light into yellow light and non-yellow light is arranged in the second row and the second column.
- the four photoelectric conversion signals obtained are always obtained even if the method of selecting unit blocks in the photosensitive cell array 200 is changed one row or one column at a time.
- This is a combination of four signals represented by equations 12-15. That is, by performing the above signal calculation while shifting the pixel block to be calculated one row and one column at a time, it is possible to obtain information on each RGB color component by the number of pixels. Therefore, the imaging apparatus of the present embodiment can generate a high-resolution color image in addition to higher sensitivity than the conventional imaging apparatus.
- the basic structure of the image sensor 10 is not limited to the configuration shown in FIG.
- the dichroic mirror 3a and the dichroic mirror 3b are interchanged and the dichroic mirror 3c and the dichroic mirror 3d are interchanged, the effect of this embodiment is not changed.
- the arrangement of the first row and the arrangement of the second row shown in FIG. 9A may be interchanged, and the dichroic mirrors 3a and 3b are arranged so as to be aligned in the column direction instead of the row direction. There is no change in its effectiveness.
- a dichroic mirror is used as the spectral element, but the spectral element may be any element as long as it separates into primary color light and its complementary color light.
- the spectroscopic element a microprism or an optical element using diffraction used in the first embodiment may be used. It is also possible to use different types of spectral elements in combination.
- the solid-state imaging device, the imaging apparatus, and the program according to the embodiment of the present invention are effective for all cameras using the solid-state imaging device.
- it can be used for consumer cameras such as digital still cameras and digital video cameras, and industrial solid-state surveillance cameras.
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Abstract
Description
(式1) S2a=Ws-C1^s+C1s=2C1s
(式2) S2b=Ws-C1s+C1^s=2C1^s
(式3) S2c=Ws-C3s+C3^s=2C3^s
(式4) S2d=Ws-C3^s+C3s=2C3s
(式5) D1=S2a-S2b=2C1s-2C1^s
(式6) D2=S2d-S2c=2C3s-2C3^s
(式7) D1=4C1s-2Ws
(式8) D2=4C3s-2Ws
すなわち、(4C1s-2Ws)および(4C3s-2Ws)の色差信号が得られる。
(式9) S2a+S2b=2Ws
(式10) S2c+S2d=2Ws
(式11) S2a+S2b+S2c+S2d=4Ws
図3は、第1の実施形態による撮像装置の全体構成を示すブロック図である。本実施形態の撮像装置は、デジタル式の電子カメラであり、撮像部300と、撮像部300から送出される信号に基づいて画像を示す信号(画像信号)を生成する信号処理部400とを備えている。なお、撮像装置は静止画のみを生成してもよいし、動画を生成する機能を備えていてもよい。
(式12)S2a=Ws-Cs+Rs=2Rs
(式13)S2b=Ws-Rs+Cs=2Cs
(式14)S2c=Ws-Bs+Ys=2Ys
(式15)S2d=Ws-Ys-Bs=2Bs
次に、図9を参照しながら、第2の実施形態を説明する。本実施形態の撮像装置は、実施形態1の撮像装置と比較して、撮像素子10の構造のみが異なっており、その他の構成要素は同一である。以下、実施形態1の撮像装置との相違点を中心に説明し、重複する点は説明を省略する。
2,2a,2b,2c,2d 撮像素子の光感知セル
3a、3b、3c、3d 分光要素(ダイクロイックミラー)
4a、4b マイクロレンズ
5 撮像素子の配線層
6a、6b 透明層
7 シリコン基板
9 固定基板
10 撮像素子
11 光学フィルタ
12 光学レンズ
13 信号発生/受信部
14 素子駆動部
15 画像信号生成部
16 画像信号出力部
17 赤(R)以外を反射する多層膜フィルタ(ダイクロイックミラー)
18 緑(G)のみを反射する多層膜フィルタ(ダイクロイックミラー)
19 青(B)のみを反射する多層膜フィルタ(ダイクロイックミラー)
20 遮光部
21 透光性の樹脂
22 G光透過の多層膜フィルタ(ダイクロイックミラー)
23 R光透過の多層膜フィルタ(ダイクロイックミラー)
24 G光透過の有機色素フィルタ
25 R光透過の有機色素フィルタ
26 マイクロレンズ
27 金属層
30 メモリ
40 光感知セルの単位ブロック
100 分光要素アレイ
200 光感知セルアレイ
300 撮像部
400 信号処理部
Claims (13)
- 各々が第1の光感知セル、第2の光感知セル、第3の光感知セル、および第4の光感知セルを含む複数の単位ブロックが2次元状に配列された光感知セルアレイと、
前記光感知セルアレイに対向して配置され、複数の分光要素を含む分光要素アレイと、を備え、
前記分光要素アレイが存在しないと仮定した場合に各光感知セルが受ける光を各光感知セルのセル入射光とし、前記セル入射光に含まれる可視光が、第1の色成分、第2の色成分、および第3の色成分から構成され、各色成分を除く色成分の可視光を、当該色成分の補色光とするとき、
前記分光要素アレイは、
前記第1の光感知セルのセル入射光から前記第1の色成分の補色光を除いた光に前記第1の色成分の光を加えた光を前記第1の光感知セルに入射させ、
前記第2の光感知セルのセル入射光から前記第1の色成分の光を除いた光に前記第1の色成分の補色光を加えた光を前記第2の光感知セルに入射させ、
前記第3の光感知セルのセル入射光から前記第3の色成分の光を除いた光に前記第3の色成分の補色光を加えた光を前記第3の光感知セルに入射させ、
前記第4の光感知セルのセル入射光から前記第3の色成分の補色光を除いた光に前記第3の色成分の光を加えた光を前記第4の光感知セルに入射させる、
固体撮像素子。 - 前記分光要素アレイは、各単位ブロックにおいて、前記第1の光感知セルに対向して配置された第1の分光要素、前記第2の光感知セルに対向して配置された第2の分光要素、前記第3の光感知セルに対向して配置された第3の分光要素、および前記第4の光感知セルに対向して配置された第4の分光要素を含み、
前記第1の分光要素は、前記第1の色成分の補色光の少なくとも一部を前記第2の光感知セルに入射させ、前記第1の色成分の光を前記第1の光感知セルに入射させ、
前記第2の分光要素は、前記第1の色成分の光の少なくとも一部を前記第1の光感知セルに入射させ、前記第1の色成分の補色光を前記第2の光感知セルに入射させ、
前記第3の分光要素は、前記第3の色成分の光の少なくとも一部を前記第4の光感知セルに入射させ、前記第3の色成分の補色光を前記第3の光感知セルに入射させ、
前記第4の分光要素は、前記第3の色成分の補色光の少なくとも一部を前記第3の光感知セルに入射させ、前記第3の色成分の光を前記第4の光感知セルに入射させる、請求項1に記載の固体撮像素子。 - 前記第1の分光要素は、前記第1の色成分の補色光の半分を前記第2の光感知セルに入射させ、前記第1の色成分の補色光の残りの半分を隣接する第1の隣接単位ブロックに含まれる1つの光感知セルに入射させ、
前記第2の分光要素は、前記第1の色成分の光の半分を前記第1の光感知セルに入射させ、前記第1の色成分の光の残りの半分を隣接する第2の隣接単位ブロックに含まれる1つの光感知セルに入射させ、
前記第3の分光要素は、前記第3の色成分の光の半分を前記第4の光感知セルに入射させ、前記第3の色成分の光の残りの半分を隣接する前記第1および第2の隣接単位ブロックの一方に含まれる1つの光感知セルに入射させ、
前記第4の分光要素は、前記第3の色成分の補色光の半分を前記第3の光感知セルに入射させ、前記第3の色成分の補色光の残りの半分を隣接する前記第1および第2の隣接単位ブロックの他方に含まれる1つの光感知セルに入射させる、請求項2に記載の固体撮像素子。 - 前記第1の分光要素は、前記第1の色成分の補色光のほぼ全てを前記第2の光感知セルに入射させ、
前記第2の分光要素は、前記第1の色成分の光のほぼ全てを前記第1の光感知セルに入射させ、
前記第3の分光要素は、前記第3の色成分の光のほぼ全てを前記第4の光感知セルに入射させ、
前記第4の分光要素は、前記第3の色成分の補色光のほぼ全てを前記第3の光感知セルに入射させる、請求項2に記載の固体撮像素子。 - 前記第1の色成分は赤および青の一方の色成分であり、前記第3の色成分は赤および青の他方の色成分である、請求項1から4のいずれかに記載の固体撮像素子。
- 前記第1の分光要素、前記第2の分光要素、前記第3の分光要素、および前記第4の分光要素の各々は、透光性部材を有し、前記透光性部材の形状、および前記透光性部材と前記透光性部材よりも屈折率の低い他の透光性部材との屈折率の差を利用して分光する、請求項1から5のいずれかに記載の固体撮像素子。
- 前記第1の分光要素、前記第2の分光要素、前記第3の分光要素、および前記第4の分光要素の各々は、ダイクロイックミラーを含み、前記ダイクロイックミラーによって分光する、請求項1から5のいずれかに記載の固体撮像装置。
- 請求項1から7のいずれかに記載の固体撮像素子と、
前記固体撮像素子に像を形成する光学系と、
前記固体撮像素子から出力される信号を処理する信号処理部であって、前記第1の光感知セルから出力される第1の光電変換信号、前記第2の光感知セルから出力される第2の光電変換信号、および前記第3の光感知セルから出力される第3の光電変換信号、前記第4の光感知セルから出力される第4の光電変換信号を用いた演算によって色情報を生成する信号処理部と、
を備える撮像装置。 - 前記信号処理部は、前記第1の光電変換信号と前記第2の光電変換信号との差分演算と、前記第3の光電変換信号と前記第4の光電変換信号との差分演算とにより、第1の色信号および第2の色信号を生成する、請求項8に記載の撮像装置。
- 前記信号処理部は、前記第1および第2の光電変換信号の加算、前記第3および第4の光電変換信号の加算、および前記第1から第4の光電変換信号の加算のいずれかを含む演算により、輝度信号を生成する、請求項8または9に記載の撮像装置。
- 請求項1から7のいずれかの固体撮像素子から出力される信号を処理する方法であって、
前記第1の光感知セルから出力される第1の光電変換信号、前記第2の光感知セルから出力される第2の光電変換信号、前記第3の光感知セルから出力される第3の光電変換信号、および前記第4の光感知セルから出力される第4の光電変換信号を取得するステップAと、
前記第1から第4の光電変換信号を用いて色情報を生成するステップBと、
を含む方法。 - 前記ステップBは、
前記第1の光電変換信号と前記第2の光電変換信号との差分を示す第1の差分信号を生成するステップと、
前記第3の光電変換信号と前記第4の光電変換信号との差分を示す第2の差分信号を生成するステップと、
を含む、請求項11に記載の方法。 - 前記ステップBは、
前記第1および第2の光電変換信号の加算、前記第3および第4の光電変換信号の加算、および前記第1から第4の光電変換信号の加算のいずれかを含む演算によって輝度信号を生成するステップと、
前記輝度信号、前記第1の差分信号、および前記第2の差分信号を用いて前記セル入射光に含まれる赤、緑、および青の色信号を生成するステップと、
をさらに含む請求項12に記載の方法。
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