JP3495979B2 - Solid-state imaging device and imaging device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image pickup device for picking up a subject image.

[0002]

2. Description of the Related Art FIG. 7 shows an example of the structure of a conventional solid-state image pickup device in which pixels each having a photoelectric conversion portion are two-dimensionally arranged.
In the figure, 101 is a pixel having a photoelectric conversion unit such as a photodiode, and by arranging the pixels two-dimensionally, a pixel region 100 for picking up a subject image is formed.

Further, 103 is a vertical signal line from which a signal from a pixel is read out, 104 is a storage capacitor for temporarily storing the signal read out to the vertical signal line, and 105 is a signal read out to the vertical signal line 103. Transfer MOS for transferring the
Transistor 106 is for holding the signal of holding capacitor 104 on horizontal signal line 10
It is a transfer MOS transistor for transferring to 7.

Reference numeral 108 denotes a vertical scanning circuit for controlling the readout of signals from the pixels to the vertical signal line for each row by sequentially scanning the pixels in one row in the horizontal direction in the vertical direction, and 109 denotes a transfer MOS transistor. By controlling 106, the horizontal scanning circuit that sequentially reads the signals accumulated in the storage capacitor 106 to the horizontal signal line 107, and 110 is a reset MOS transistor for resetting the horizontal signal line.
In addition, 107 is a constant current source that forms a source follower together with a transistor included in the pixel.

Here, the arrangement of the color filters of the conventional solid-state image pickup device will be described. FIG. 8 shows an example of such a case, in which the first color filter (20
1), a second color filter (202) that transmits green light,
It is a third color filter (203) that transmits blue light. Then, corresponding to each of the two-dimensionally arranged pixels, the first color filter and the second color filter are alternately arranged in an odd number column starting from the first column of pixels,
Second and third color filters are alternately arranged in an even-numbered column starting from the second column of pixels. Further, in the odd-numbered columns and the even-numbered columns, the second color filters are arranged so as not to be adjacent to each other in the horizontal direction.

Generally, as shown in FIG. 9, a microlens corresponding to each pixel is used to realize high sensitivity of a solid-state image pickup device. A cross-sectional structure of a unit pixel of a solid-state image sensor having a microlens is shown in the figure. The unit pixel is indicated by 300 (corresponding to one pixel 101 in FIG. 7). The unit pixel includes a photoelectric conversion unit 301, an insulating layer 302, wiring layers 303 and 304, a light shielding layer 305, a protective film 306, flattening layers 307 and 309, a color filter layer 308, and a microlens 310. a is the lens diameter and b is the lens thickness. With this micro lens,
It improves the efficiency of collecting incident light and realizes high sensitivity.

Next, a general microlens manufacturing method will be described with reference to FIG. A transparent resin 409 is applied on the color filter layer 408 to planarize it. Next, a microlens material 410 made of an organic resin is applied, and the pattern is exposed with a mask. a'is the pattern size and b'is the film thickness b'of the microlens material. Thus, as shown in the figure, a space 411 for separating the microlenses is formed by development, and a desired microlens is formed by fluidization and solidification by heat treatment.

[0008]

As described above, the conventional solid-state image pickup device has a structure in which a plurality of color filters are arranged in the pixel region 101 as shown in FIG.

However, in this method, in the case of a solid-state image pickup device having a pixel pitch of 10 μm and a horizontal pixel number of 640 pixels and a vertical pixel number of 480 pixels, the focal length of the lens that gives the standard angle of view is the diagonal of the solid-state image pickup element. 8m long
m.

For this reason, there is a limit to reduction in thickness when an image pickup device such as a digital camera is manufactured using such a solid-state image pickup device.

[0011]

As one means for solving the above problems, a plurality of pixel regions in which pixels including a photoelectric conversion portion are two-dimensionally arranged are provided adjacent to each other with a predetermined space provided. together disposed on the same semiconductor chip to form a microlens on the plurality of pixel regions Te, pixel
There is provided a solid-state image pickup device , characterized in that a microlens is formed on the predetermined space where no is formed .

Further, a plurality of lenses for forming a plurality of subject images, and a plurality of pixel regions in which pixels each including a photoelectric conversion unit for receiving the light formed by the plurality of lenses are arranged two-dimensionally. A plurality of color filters are respectively formed on the front surfaces of the plurality of pixel regions, and the plurality of pixel regions are arranged adjacent to each other with a predetermined space provided on the same semiconductor chip, to form a microlens on the plurality of pixel regions, image
There is provided an imaging device characterized in that a microlens is formed on the predetermined space on which no element is formed . Furthermore, the pixels including the photoelectric conversion unit are arranged in a two-dimensional array.
A plurality of pixel areas, each with a predetermined space
The plurality of pixels are arranged adjacent to each other on the same semiconductor chip.
A microlens is formed on the area and the predetermined
The micro lens is formed on the space of
Number of pixel regions is at least the first, second and third pixels
A first pixel region from the subject
Of the color components of the
Of the second color component of the
A solid characterized by receiving a third color component from the body
An image sensor is provided. In addition, multiple subject images
With a plurality of lenses for imaging and the plurality of lenses
Pixels including photoelectric conversion units that receive the imaged light respectively
A plurality of pixel regions arranged two-dimensionally and the plurality of pixels
Multiple color filters, each formed on the front of the area
And each of the plurality of pixel regions has a predetermined space.
-Providing a spacer and arranging them adjacently on the same semiconductor chip,
When forming microlenses on multiple pixel areas
, Forming a microlens on the predetermined space,
The plurality of pixel regions include at least first, second and third pixel regions.
And the first pixel region is from the subject.
Of the first color component of the
The second color component from the body is received and the third pixel region is received.
Is characterized by receiving the third color component from the subject.
An image pickup device for performing the same is provided. Furthermore, a pixel including a photoelectric conversion unit
A plurality of pixel regions arranged two-dimensionally, and their respective predetermined
Spaces adjacent to each other and arranged adjacent to each other on the same semiconductor chip
Then, a microlens is formed on the plurality of pixel regions.
At the same time, form a micro lens on the specified space.
Output from each of the plurality of pixel areas.
A signal processing unit that synthesizes signals to form an image and
A number of pixel regions and a driver for driving the signal processing unit.
Imming generator, the signal processor, and the timing
A control / arithmetic unit for controlling the generating unit,
An image pickup device for performing the same is provided.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a schematic diagram of a solid-state image sensor according to an embodiment of the present invention.

Reference numeral 1 is a solid-state image pickup element of the same semiconductor chip formed by, for example, a CMOS process, and has a configuration described below.

Reference numerals 2a to 2b are pixel areas for picking up a subject image, and the respective pixel areas have pixels arranged two-dimensionally. Further, each pixel region has an image forming system (lens) corresponding to each pixel region, and the same subject image is captured in each pixel region (see FIG. 5 described later). Further, color filters (hereinafter referred to as G filters) 3a and 3c having a spectral transmission characteristic for mainly transmitting green are formed on the front surfaces of the pixel areas 2a and 2c, and the front surfaces of the pixel areas 2b are mainly formed. A color filter (hereinafter referred to as a B filter) 3b having a spectral transmission characteristic that transmits blue color is formed on the front surface of the pixel region 2d, and a color filter having a spectral transmission characteristic that mainly transmits red color (hereinafter R filter) 3d is formed.

Then, different color signals are output from the respective pixel areas, and the color signals are synthesized by combining them.
An image is formed.

The area 3 in which the color filter is formed is formed not only in the pixel area but also in the peripheral area of the pixel area (including between the pixel area and the pixel area). Further, although one microlens is provided for each pixel, the region 4 in which the microlens is formed is not limited to the pixel region, but may be between the pixel region and the pixel region or between the pixel regions. Is also formed in the peripheral region of the.

Next, the plurality of pixel regions 2a ...
Illustration of details about 2d and its surrounding area
Perform using 2.

Reference numeral 10 is a pixel including a photoelectric conversion unit such as a photodiode (details will be described later), 11 is a vertical signal line from which a signal from the pixel is read out, and 12 is a row of pixels in a horizontal direction which are collectively reset. , A vertical scanning circuit that performs selection and the like and sequentially scans in the vertical direction row by row, 13 is a control line for transmitting a reset pulse, a selection pulse, or the like from the vertical scanning circuit to the pixel, and 14 is a signal included in the pixel A load current source that forms a source follower with a MOS transistor (described later) for amplifying and reading, 15 is a storage capacitor in which signals of pixels in one row are accumulated, and 16 is a transfer capacitor for transferring a signal from the pixel to the storage capacitor. A transfer MOS transistor, 17 is a transfer MOS transistor for transferring a signal from the storage capacitor to the horizontal signal line 18, 19
Is a horizontal scanning circuit for controlling the transfer MOS transistor to sequentially transfer the signal from the storage capacitor to the horizontal signal line 18,
Reference numeral 20 is an amplifier for amplifying and outputting the signal of the horizontal signal line, and 21 is a reset MOS transistor for supplying a reset level for resetting the horizontal signal line.

In the present embodiment, the distance between the pixels at the extreme ends of the pixel areas adjacent to each other is made larger than the pixel pitch of the pixels in each pixel area.

FIG. 3 is a diagram for explaining the details of the pixel of FIG.

Reference numeral 31 is a photoelectric conversion unit such as a photo diode, and 32.
Is a source follower input that receives the signal from the photoelectric conversion unit at the gate electrode, amplifies the signal and outputs it from the source electrode.
A MOS transistor, 33 is a reset MOS transistor for supplying a reset level to the gate electrode of the MOS transistor, 34 is a transfer MOS transistor for transferring the signal of the photoelectric conversion unit 31 to the gate of the MOS transistor, and 35 is A selection MOS for supplying a predetermined voltage to the drain of the MOS transistor so that the signal level corresponding to the signal level of the gate electrode of the MOS transistor 33 is read out to the output signal line.
It is a transistor.

Next, the operation of the solid-state image sensor described with reference to FIG. 2 will be described.

First, the pixels 10 in a plurality of pixel areas are reset row by row. After that, the photoelectric conversion unit included in the pixel 10
31 signals are transferred to the storage capacitor 15 for each row,
The signals stored in the horizontal scanning circuit 19 are sequentially read by the horizontal scanning circuit 19 to the horizontal signal line 18.

As a result, from the amplifier 20, first the pixel area
A row of signals from 2d (R signal: a signal generated by an optical signal mainly passing through a filter transmitting red) is read out, and then a row of signals from the pixel area 2c (G signal: mainly The signal generated by the optical signal through the filter transmitting the green color) is read. Then, such an operation is sequentially repeated.

After the above-described operation is repeated, the amplifier 20 first outputs a signal of one row from the pixel area 2a (B signal: a signal generated by an optical signal mainly passing through a green filter). Is read out, and then a row of signals (B signal: a signal generated by an optical signal that has passed through a filter mainly transmitting blue) from the pixel region 2b is read out. Then, such an operation is sequentially repeated.

FIG. 4 is a sectional view taken along the line AB in FIG.

41 is a photoelectric conversion part, 42 is a wiring layer, 43 is an insulating layer,
44 is a light-shielding layer, 45 is a protective film, 46 is a flattening layer, 47 is a G filter, 48 is an R filter, and 49 is a microlens.

As can be seen from FIG. 4, microlenses are also formed in the peripheral area between the pixel areas 2a and 2b for the following reason.

The distance b between the pixel areas shown in FIG. 2 is larger than the pixel pitch a. However, if it is too large, the chip area of the solid-state image pickup element becomes too large. , The distance b cannot be increased so much.

Therefore, by providing the microlenses in the peripheral area, it is possible to prevent light having an angle that should originally be incident on the pixel area 2b from entering the pixel area 2a. That is, by providing a microlens in the peripheral area, light incident on the peripheral area at an angle is condensed below the peripheral area,
It is possible to prevent light from entering the 2a side.

Further, since the color filter and the microlens are formed also in the peripheral area, the nonuniformity of the shape of the boundary portion of the color filter and the color filter does not affect the pixel area, and the sensitivity is lowered or It is possible to avoid uneven sensitivity.

FIG. 5 shows the solid-state image pickup device described above,
It is a figure showing the relationship of the lens which forms the light from a to-be-photographed object on the solid-state image sensor.

Reference numeral 51a is a lens for forming a subject image on the pixel area 2a, 51b is a lens for forming a subject image on the pixel area 2b, and 51c is a lens for forming a subject image on the pixel area 2c. , 51d are lenses for forming a subject image on the pixel area 2d.

As described above, in the present embodiment, the subject image is divided into a plurality of subject images, and the respective pixel regions are imaged. Therefore, the pixel region of the solid-state image pickup device having the structure as in the conventional example is used. Compared with the above, each pixel area of the present embodiment becomes smaller, the focal length of the lens can be shortened, and when an imaging device such as a digital camera is configured, it can be thinned.

The above-described embodiment shows an example of the pixel structure, and may have another structure, for example, a structure other than the MOS transistor.

Further, a CCD may be used instead of the CMOS sensor described above.

Further, although the areas where the microlenses and the color filters are formed are shown as being in agreement, they may not necessarily be in agreement.

The color filter is not limited to the on-chip filter described above, but a color filter may be provided outside the semiconductor chip.
The array of color filters may be other than those shown above, for example, complementary color filters.

Further, although the pixel area described above has a structure without optical black, it may have a structure having optical black.

Further, in this embodiment, the pixel area is 4
Two are shown, for example, the pixel area for G filter, B
Pixel area for filter and pixel area for R filter 3
It may have one configuration.

A case where the solid-state image pickup device 1 described above is applied to an image pickup apparatus such as a still camera will be described with reference to FIG.

FIG. 6 is a block diagram showing a case where the solid-state image pickup device 1 is applied to a still camera.

In FIG. 6, reference numeral 61 denotes a barrier which also serves as a lens protector and a main switch, and 51 (lenses 51a to 51a in FIG. 5).
(Equivalent to 51d) is a lens that forms an optical image of the subject on the solid-state image sensor 1, 1 is a solid-state image sensor that captures the subject imaged by the lens 51 as an image signal, and 71 is the amount of light that has passed through the lens 51. A diaphragm for changing, 62 is a solid-state image sensor 1
An image pickup signal processing circuit that performs various corrections and clamps on the image signal output from the solid-state image pickup device, 63 is an A / D converter that performs analog-digital conversion of the image signal output from the solid-state image pickup device 1, and 64 is an A / D converter. A signal processing unit for synthesizing signals output from the converter 6 from the respective pixel regions to form image data,
65 is a timing generator that outputs various timing signals to the solid-state imaging device 1, the imaging signal processing circuit 62, the A / D converter 63, and the signal processing unit 64, and 66 is overall control that controls various operations and the entire still video camera. A computing unit, 67 is a memory unit for temporarily storing image data, 68 is an interface unit for recording or reading on a recording medium, and 69 is a semiconductor memory or the like for recording or reading image data. A removable recording medium, 70 is an interface unit for communicating with an external computer or the like.

Next, the operation of the still video camera having the above-described structure at the time of shooting will be described.

When the barrier 61 is opened, the main power source is turned on, then the control system power source is turned on.
The power supply of the imaging system circuit such as the / D converter 63 is turned on.

Then, in order to control the exposure amount, the overall control / arithmetic unit 66 opens the diaphragm 71, the signal output from the solid-state image pickup device 1 is converted by the A / D converter 63, and then signal processed. Input to the part 64. The exposure calculation is performed by the overall control / calculation unit 66 based on the data.

The brightness is determined based on the result of the photometry, and the overall control / calculation unit 66 controls the diaphragm according to the result.

Next, based on the signal output from the solid-state image pickup device 1, high frequency components are extracted and the distance to the object is calculated by the overall control / calculation unit 66. After that, the lens is driven to determine whether or not it is in focus. When it is determined that the lens is not in focus, the lens is driven again to measure the distance.

Then, after the focus is confirmed, the main exposure starts.

When the exposure is completed, the image signal output from the solid-state image sensor 1 is A / D converted by the A / D converter 6,
It is passed through the signal processing unit 64 and written in the memory unit by the overall control / arithmetic unit 66.

After that, the data accumulated in the memory unit 67 is controlled by the recording medium control I / O under the control of the overall control / arithmetic unit 66.
It is recorded on a removable recording medium 69 such as a semiconductor memory through the F portion.

Further, the image may be processed by directly inputting it to a computer or the like through the external I / F section 70.

In the present embodiment, as described above, the solid-state image pickup device 1, the image pickup signal processing circuit 62, and the A / D converter 6 are used.
3 shows that the signal processing unit 64 and the like are formed by separate semiconductor chips, but these are formed on the same semiconductor chip by, for example, a CMOS process, and the imaging signal processing circuit 62, A / D
The converter 63, the signal processing unit 64, and the like may be formed in the peripheral region of the solid-state imaging device 1.

[0055]

By using the solid-state image pickup device of the present invention, a thin image pickup device can be provided.

[Brief description of drawings]

FIG. 1 is a diagram schematically showing a solid-state image sensor according to an embodiment of the present invention.

FIG. 2 is a diagram showing details of a solid-state image sensor according to an embodiment of the present invention.

FIG. 3 is a diagram showing details of pixels included in the solid-state image sensor according to the embodiment of the present invention.

FIG. 4 is a cross-sectional view of a solid-state image sensor according to an embodiment of the present invention.

FIG. 5 is a diagram showing a solid-state image sensor and a lens according to an embodiment of the present invention.

FIG. 6 is an imaging device using the solid-state imaging device according to the embodiment of the present invention.

FIG. 7 is a diagram showing details of a conventional solid-state imaging device.

FIG. 8 is a diagram showing an array of conventional color filters.

FIG. 9 is a diagram showing a cross-sectional view of a conventional solid-state imaging device.

FIG. 10 is a diagram showing a cross-sectional view of a conventional solid-state image sensor.

[Explanation of symbols]

1 Solid-state image sensor 2 pixel area 3 Area where the color filter is formed 4 Area where micro lens is formed

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Claims (11)

(57) [Claims] 1. A plurality of pixel regions in which pixels each including a photoelectric conversion unit are two-dimensionally arranged are provided adjacent to each other on a same semiconductor chip with a predetermined space, and the plurality of pixel regions are arranged on the plurality of pixel regions. to form a microlens, pixels
A solid-state imaging device , wherein a microlens is formed on the predetermined space that is not formed. 2. A scanning circuit for selecting pixels included in the pixel region is provided on the same semiconductor chip on a side of the pixel region that is not adjacent to the other pixel regions. The solid-state imaging device according to claim 1.
Child . 3. The plurality of pixel areas have at least first, second and third pixel areas, and the first pixel area receives a first color component from a subject, and the first pixel area receives the first color component. 3. The second pixel area receives the second color component from the subject, and the third pixel area receives the third color component from the subject. Either one
Item 7. The solid-state image sensor according to item. 4. The first color component is a red color component, and the second color component is the second color component.
The solid-state imaging device according to claim 3, the color components green color component, and the third color component is characterized by a blue component. 5. A plurality of lenses, each of which forms a plurality of subject images, and a plurality of pixel regions, in which pixels each including a photoelectric conversion unit that receives the light formed by the plurality of lenses, are two-dimensionally arranged. A plurality of color filters are respectively formed on the front surfaces of the plurality of pixel regions, and the plurality of pixel regions are provided adjacent to each other with a predetermined space, respectively, on the same semiconductor chip, to form a microlens on the plurality of pixel regions, pixel
The predetermined space is not formed - imaging apparatus characterized by forming a micro lens on the scan. 6. A scanning circuit for selecting a pixel included in the pixel region is provided on the same semiconductor chip on a side of the pixel region which is not adjacent to the other pixel region. The image pickup apparatus according to claim 5. 7. The plurality of pixel regions have at least first, second and third pixel regions, and the plurality of color filters include at least first, second and third color filters. And having the first color filter,
The first color component from the subject is transmitted, and the second color component is transmitted.
Filter, passes through the second color component from the object, the third color - filter, claim 5 or claim 6, characterized in that passing through the third color component from the object The imaging device according to item 1. 8. The first color component is a red component and the second color component is the second component.
Color component green color component of the third color component image pickup apparatus according to claim 7, characterized in that the blue component. 9. Two-dimensional array of pixels including photoelectric converters
Predetermined space for each of the multiple pixel areas
And adjacent to each other on the same semiconductor chip,
In addition to forming a microlens on the elementary region,
A micro lens is formed on a fixed space.
The plurality of pixel regions includes at least the first, second and third pixels.
A first pixel region, and the first pixel region is a first pixel region from a subject.
1 color component is received, and the second pixel area is an object.
Of the second color component, and the third pixel region is
It is characterized by receiving the third color component from the object.
Body image sensor. 10. Form multiple subject images
Multiple lenses, Receiving the light imaged by the lenses
A plurality of images in which pixels including a photoelectric conversion unit are arranged two-dimensionally.
Elementary regions, The plurality of pixel regions formed on the front surfaces of the plurality of pixel regions, respectively.
Has a color filter, Each of the plurality of pixel regions is provided with a predetermined space.
And adjacent to each other on the same semiconductor chip,
In addition to forming a microlens on the elementary region,
A micro lens is formed on a fixed space, and
The pixel region is at least the first, second and third pixel regions.
And the first pixel region is a first color from the subject.
Receiving a component, the second pixel area is
The second color component is received, and the third pixel area is an object.
Image pickup device characterized by receiving the third color component
Place 11. Pixels including photoelectric conversion units are arranged in a two-dimensional pattern.
Set a predetermined space for each of the pixel areas
And adjacent to each other on the same semiconductor chip,
In addition to forming a microlens on the pixel area,
A microlens is formed on a predetermined space.
The signals output from multiple pixel areas are combined.
And a signal processing unit for forming an image, and
And a timing generator for driving the signal processor
And controls the signal processing unit and the timing generation unit.
An image pickup apparatus comprising: