JPH03185977A - Solid-state image pickup device - Google Patents

Abstract

PURPOSE:To facilitate the signal processing and to prevent color mixture by forming part of a CCD charge transfer vertical register with a transparent transfer electrode, applying photoelectric conversion, and using the vertical register as a 2nd picture element group storing generated charge. CONSTITUTION:A 3-phase drive CCD charge transfer vertical register 121 sets a transfer electrode phi3 among transfer electrodes phi1-phi3 receiving 3-phase clock pulses to a low level and sets the transmission electrodes phi1, phi2 to a high level. Thus, the vertical register 121 acts like a 2nd picture element group storing the charge generated through photoelectric conversion as well as like a 1st picture element group transferring the charge stored in picture element arrays 11a, 12a, transfers the charge generated in itself to the lowermost section and gives the charge to a horizontal register 21 thereby transferring the charge generated by the 1st picture element group. As a result, in the case of color reproduction, since the color signal is outputted in time series for each color signal, then even when the transfer efficiency of the horizontal register 21 is deteriorated, the possibility of mixed color is precluded and the signal processing is easily implemented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Field of Industrial Application) The present invention relates to a CCD type solid-state imaging device, and particularly to a device suitable for high integration.

(Prior Art) A CCD type solid-state imaging device is used in an electronic still camera 50 having a mechanical shutter function as shown in FIG. Optical image information is provided to the solid-state imaging device 54 through a lens 52 and a mechanical shutter 53 mounted on a housing 51, converted into an electrical image signal, and recorded on a magnetic disk (not shown).

A conventional solid-state imaging device 54 mounted on such a camera 50 will be described with reference to FIG. 6, which shows its configuration. Pixels 11, 12, and 13 that perform photoelectric conversion are arranged in the vertical direction, respectively, to form pixel columns 11a, 12a, and 13a, and are arranged in a two-dimensional grid as a whole. Each pixel row 11a to 13a has three primary colors of light (green (G), red (R), blue (B)).
Color filters 101, 102, and 103 are formed to enable color imaging. Furthermore, each pixel column 1
Light shielding films 101, 102 and 10 are provided on 1a to 13a.
3 are formed respectively.

Vertical registers 31, 32 and 33 are arranged in the vertical direction between each of the pixel columns 11a to 13a.

The vertical registers 31 to 33 each have an adjacent pixel column 1.
1a to 13a are given the accumulated signal charges and sequentially transferred downward.

The signal charges transferred to the bottom by the vertical registers 31 to 33 are given to the horizontal register 21, sequentially transferred to the left, and output to the output section 22. In the output section 22, this signal charge is converted into a signal voltage and output to the outside of the device.

(Problems to be Solved by the Invention) However, the conventional solid-state imaging device having such a configuration has the following problems.

The signals outputted from the output unit 22 are G, R, B, G, R, B in chronological order as shown in FIG.

. . . are carried out in this order. Therefore, if the transfer efficiency of the horizontal register 21 is poor, color mixing will occur, resulting in image deterioration. Furthermore, the signal output from the output section 22 is
Since it is necessary to separately process each of the primary colors G, R, and B, a technique is required to perform complex signal processing at high speed.

There was also the problem that it was difficult to improve the degree of integration in the horizontal direction. The width required in the horizontal direction is the element width Ll, vertical register width L3, and pixels 11 to 1 for each primary color.
This value is the sum of the field shift portion width L2 that controls charge transfer from 3 to the vertical register, and the element isolation region width L4 between the pixels 11 to 13 and the vertical register. Therefore, the pitch 3P of the three primary colors is 3P-3.(L1+L2+L3+L4).

Here, each dimension is Ll-4ums L2-2umsL3
= 3 μm and L4 = 1 μm, the pitch P per -pixel column is required to be 10 μm. Considering use with a general camera, if the optical system of the lens is 2/3 inch, the horizontal direction will be 8 to 9 m, so the number of horizontal pixels will be 80.
It will be 0 to 900.

With this number of pixels, the resolution is too low to be used as an electronic still camera compared to a normal 35am size camera using silver halide.

The present invention has been made in view of the above circumstances, and provides a solid-state imaging device that can easily perform signal processing, can effectively prevent color mixture, and can improve horizontal resolution without reducing sensitivity. The purpose is to

[Structure of the invention]

(Means for Solving the Problems) A solid-state imaging device of the present invention includes a plurality of first pixel groups in which pixels that accumulate charges generated by photoelectric conversion are vertically arranged, and each of the first pixel groups. The first pixel group is arranged vertically between columns or between every other column and transfers the accumulated charge to the bottom.<CCD type charge transfer vertical register and CCD type charge transfer A horizontal register is arranged horizontally adjacent to the bottom of the vertical register, and receives the charge transferred by the CCD type charge transfer vertical register and transfers it in the horizontal direction, and a horizontal register receives the charge from the horizontal register. The CCD type charge transfer vertical register is equipped with an output section for outputting to the outside of the device, and at least a portion thereof is formed of a transparent electrode type transfer electrode, and also functions as a second pixel group for accumulating charges generated by photoelectric conversion. However, after the charges generated in the second pixel group are transferred to the bottom and applied to the horizontal register, the charges generated in the first pixel group are transferred.

(Function) The CCD type charge transfer vertical register not only transfers the charges generated and accumulated in the first pixel group, but also transfers the charges generated by photoelectric conversion in the portion formed by the transparent electrode type transfer electrode. It also functions as a second pixel group for accumulation. Then, the charges generated by itself are transferred toward the bottom and applied to the horizontal register, and then the charges generated by the first pixel group are transferred. As a result, the charges generated in the second pixel column are first output from the output section, and then the charges generated in the first pixel column are output. As a result, when performing color reproduction, each color signal is output in time series, so there is no risk of color mixing even if the transfer efficiency of the horizontal register is poor, and it is not necessary to process each color separately. There is no
There is no need for technology to perform complex signal processing at high speed.

Further, since the CCD type charge transfer vertical register is also used as the second pixel group, the degree of integration in the horizontal direction is improved compared to the case where only the charge transfer function is provided.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.

FIG. 1 shows the configuration of this embodiment. The difference from the conventional case is that the CCD-type charge transfer vertical register (hereinafter referred to as vertical register) 121 is used not only to transfer signals from the pixel columns 11a1 and 12a, but also as the second pixel group. There is.

That is, the vertical register 121 has not only a charge transfer function but also a photoelectric conversion function. Here, the vertical register 121 is composed of a light-transmitting transfer electrode such as polycrystalline silicon, and furthermore, on top of the transfer electrode,
The light shielding films 111 to 113 as in the conventional case are not formed so that it can be used as a pixel.

The overall configuration includes this vertical register 121 and a pixel column 11 as a first pixel group arranged adjacent to it.
a1 and 12a1, horizontal register 21, and output section 22
It is equipped with A green color filter 101 and a blue color filter 103 are formed on the pixel columns 11a1 and 12a, respectively, and a red color filter 102 is formed on the vertical register 121.

The operation of this embodiment having such a configuration will be described next. Here, it is assumed that the vertical register 121 is driven in three phases. Then, transfer electrodes to which three-phase clock pulses are applied are connected to Φ1. Φ2. and Φ3, and Φ
3 is set to low level, and Φ1 and Φ2 are set to high level. Thereby, the vertical register 121 also functions as a second pixel group, and the charge pattern generated by photoelectric conversion is accumulated under the transfer electrodes Φ1 and Φ2 of the vertical register 121.

First, when the mechanical shutter of the camera is closed, the charges accumulated in the pixel columns 11a1 and 12a as the first pixel group and the charges accumulated in the vertical register 121 are transferred via the vertical register 12. Disposed of outside. When the mechanical shutter opens, pixel row 11
Photoelectric conversion is performed in the a and 12a1 vertical registers 121, and the generated signal charges are accumulated.

After the mechanical shutter closes, the accumulated signal charges are read out. When a three-phase clock pulse is applied to the transfer electrode of the vertical register 121, the signal charge accumulated in the vertical register 121 itself is first transferred downward, and then from the bottom via the horizontal register 121 to the output section 22. It is output externally as a signal voltage. As a result, only the signal of the second pixel group corresponding to the red (R) signal is read out and recorded on an external storage device such as a floppy disk.

Next, the signal charge (green (B) signal) accumulated in the pixel column 11a of the first pixel group is transferred to the vertical register 1
Transferred to 21. Then, as in the case of the R signal described above, the signal is transferred to the lower part of the vertical register 121 by application of a clock pulse, and is converted into a signal voltage from the output section 22 via the horizontal register 21 and output. Then, it is recorded in an external storage device.

Finally, pixel column 1. corresponding to the other first pixel group.
Transfer of the signal charge (blue (B)) signal accumulated in 2a is performed in the same manner as in the case of the pixel column 11a described above. As a result, the signal charge pattern imaged by the solid-state imaging device according to this embodiment is recorded in the external storage device.

In this way, unlike the conventional case, in this embodiment, each signal is output independently for each primary color (G, R, B) as shown in FIG. 2, so the transfer efficiency is particularly excellent. Even if it is not used, color mixing will not occur and image deterioration will be prevented.

Further, the pitch 3P in the horizontal direction is the width (2L1) of the two pixel columns 11a and 12a, as shown in FIG.
The total width of the vertical register (L3), the width of the two field shift sections (2L2), and the element isolation region width (L4) is 3P-3・(2L1+2L2+L3+L4).
).

Here, as in the conventional case described above, each dimension is Ll-
4, czm, L2-2ttmSL3-3um.

If L4-1 μm, then 16 μm is sufficient for the pitch 3P. Therefore, the pitch P per pixel row is 5.3 μm, which is about half the size of the conventional case (P−10 μm).

1 As a result, when the optical system of the lens is 2/3 inch (horizontal width is 8 to 9++ un), the number of pixels in the horizontal direction increases to 1500 to 1700.

As a result, it becomes possible to satisfy the demand for a larger number of pixels, which is necessary for electronic still cameras to compete with silver halide film cameras. Even if the pitch size in the horizontal direction is reduced, the pixel size remains the same as before, and performance deterioration such as a decrease in sensitivity can be prevented.

FIG. 4 shows a case where the solid-state imaging device according to this embodiment is incorporated into an electronic still camera 42 and used. Subject 4
1 (G, R, B) is converted into a signal voltage by a solid-state imaging device for each primary color, and is recorded on the magnetic disk 43. Therefore, when printing the color reproduced image 45 in the color printing device 44, it is only necessary to sequentially read out the signals from the disk 44 and print them synchronously as they are, eliminating the need for complicated signal processing and easily configuring an electronic camera system. becomes possible.

The embodiments described above are merely examples and do not limit the present invention. For example, in this embodiment, the vertical registers are driven by 3
However, it may be driven using other two phases or four phases. Further, a light shielding film may be formed on the transfer electrode that is maintained at a low level voltage during photoelectric conversion.

In this embodiment, the color filters are arranged in a stripe pattern for each pixel column or vertical register, but they can also be arranged in a mosaic pattern. In this case, each filter will be composed of complementary colors instead of primary colors. Further, as in this embodiment, the first pixel group does not need to exist on both sides of the vertical register, and when color filters are arranged in a mosaic pattern, they may be provided only on one side.

〔Effect of the invention〕

As explained above, in the solid-state imaging device of the present invention, the vertical register not only transfers the charges generated and accumulated in the first pixel group, but also functions as a second pixel group that photoelectrically converts and accumulates the generated charges. also functions, and after transferring the generated charge toward the bottom and outputting it, the charge generated in the first pixel group is transferred, so when performing color reproduction, each color signal is output in time series, and color mixing is performed. This prevents image deterioration without causing any risk of image deterioration, and allows signal processing to be performed easily. Furthermore, since the vertical register is also used as the second pixel group, the degree of integration in the horizontal direction is improved compared to the case where only a charge transfer function is provided, and high resolution can be achieved.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of a solid-state imaging device according to an embodiment of the present invention, FIG. 2 is an explanatory diagram showing the output state of time-series signals output from the device, and FIG. 3 is the same. An explanatory diagram showing the pitch of each element arranged in the horizontal direction of the device,
FIG. 4 is an explanatory diagram showing the configuration of an electronic still camera system to which the device can be applied, and FIG. 5 is an explanatory diagram showing the configuration of an electronic still camera to which the solid-state imaging device of the present invention can be applied. 6 is a block diagram showing the configuration of a conventional solid-state imaging device, FIG. 7 is an explanation showing the output state of time-series signals output from the device, and FIG. 8 is a diagram of the device. It is an explanatory view showing pitch of each element arranged in the horizontal direction. 11.12... Pixel, lla, 12a... Pixel column,
21...Horizontal register, 22...Output section, 41...
・Subject, 42...Camera, 43...Magnetic disk, 44...Color printing device, 45...Color reproduction image, 101° 102.103...Color filter, 121
...Vertical register.

Claims (1)

[Claims] A plurality of first pixel groups in which pixels that accumulate charges generated by photoelectric conversion are arranged vertically, and vertically arranged between each column of the first pixel group or between every other column. is,
a CCD-type charge transfer vertical register that receives charges accumulated in the first pixel group and transfers them to the bottom;
a horizontal register that is arranged horizontally adjacent to the bottom of the CD-type charge transfer vertical register, and receives the charge transferred by the CCD-type charge transfer vertical register and transfers it in the horizontal direction; and the horizontal register. said C
The CD-type charge transfer vertical register is formed at least in part by a transparent electrode-type transfer electrode, and also functions as a second pixel group that accumulates charges generated by photoelectric conversion.
A solid-state imaging device characterized in that the charges generated in the first pixel group are transferred to the bottom and transferred to the horizontal register, and then the charges generated in the first pixel group are transferred.