JPS58125978A - Driving method of charge transfer image pickup device - Google Patents

Abstract

PURPOSE:To prevent the horizontal drift of pictures as well as the blur of the reproduced pictures at the right side of a TV screen, by applying at all times a fixed amount of bias charge to a horizontal shift register from a charge input part. CONSTITUTION:For a constitution consisting of vertical shift registers 10, photoelectric converting elements 11, a horizontal shift register 12 and a charge detecting part 13, a fixed amount of bias charge 70 is always applied to the register 12 from a charge input part 60. This charge 70 and the signal charge 71 are stored in both a terminal region 36 of the register 10 and a channel region 37 of the register 12 which are covered with a part of a horizontal charge transfer electrode. In such a way of operation, the signal charge is always transferred with high efficiency by the register 12. As a result, the horizontal drift which is produced when a subject of high luminance is picked up and the blur occuring to the reproduced pictures at the right side of the TV screen can be completely prevented. Furthermore the dynamic range is greatly improved for the register 12.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a solid-state imaging device using a telegraph transfer device. Solid-state imaging devices are characterized by their small size, low cost, power, and reliability, and because they do not suffer from burn-in unlike image pickup tubes, they have recently been researched and developed in many fields. .

Figure 1 schematically shows the so-called interline transfer method among telegraph transfer imaging devices using hyl5, and a vertical shift register group consisting of multiple rows of telegraph transfer devices.
, a photoelectric conversion element group l1 arranged adjacent to one side of each vertical shift register, a horizontal shift register l2 electrically coupled to one end of each vertical shift register, and a charge detection device provided at one end of the horizontal shift register l2. It consists of a section 13.

FIG. 2 is an enlarged view of the coupling region 14 between the vertical shift register group lO and the horizontal shift register l2 among the charge transfer imaging equipment not shown in FIG. electrodes 21 , 22 and the vertical transformer 7 agate electrode 23 that controls the transfer of signal charges from the vertical shift register lO to the horizontal shift register 12
covered with Further, the channel region 24 of the horizontal shift lens 12 is connected to the horizontal charge transfer electrodes 25, 26, 27° 28
．． It's popular at 29. Further, in the figure, the vertical shift register 10 and the horizontal shift register 12 are electrically coupled by covering the end region 30 of the channel region 20 with a part of the horizontal 1 mm transfer device 27.

FIG. 93 schematically shows a cross section on the edge of the joint region shown in FIG. 2. The above-mentioned vertical charge transfer electrodes 21, 22 .
Vertical transfer gate voltage $23. Horizontal charge transfer%2
7 is formed. Under each of the above electrodes, there is a buried channel layer 3 having a conductivity opposite to that of the substrate semiconductor, for example.
3 is formed, and a channel stop region 34 doped with, for example, a conductive impurity opposite to the impurity of the buried channel layer 33 is formed outside the channel region. Further, the main surface of the semiconductor is shielded from light by, for example, a metal layer 35. In the figure, a '44 area 36 indicates the area 30 of FIG. 2 which electrically couples the vertical shift register and the horizontal shift register, and an ill area 37 indicates the channel area of the horizontal shift register.

In order to manufacture a charge transfer imaging device having such a structure, as shown in FIG. ! After being read into the vertical shift register group lO, the downward KF is read out in parallel within the vertical shift register group lO every horizontal scanning period (IH) of the video signal.
@Next forwarded.

The signal charge transferred to the end of the vertical shift register group 10 is transferred to the horizontal shift register 12 in the horizontal scanning period (IH) in which the vertical transfer gate electrode 23 is turned on.
are injected in parallel. The signal electric hook sent to the horizontal shift register 12 is sequentially transferred in the horizontal direction while signal charges are transferred from the vertical shift register group 10 in the next cycle, and is output from the charge detection unit 13 to the outside as a video signal. taken out.

With such conventional digital transfer imaging equipment, when a luminance normal object is used, the image may flow horizontally, or only the reproduction m* on the right side of the TV screen may be blurred. An unfavorable phenomenon was observed. This phenomenon has been the cause of color shift or color shading when the electromagnetic transfer imaging device is applied to a single-chip color camera.

This phenomenon is caused by the structure of the coupling region of the vertical shift register and horizontal shift register shown in FIG. 2 or 3. 4 (a), (b), and (c) schematically show the potential distribution in each part of the cross-sectional view of the bond wA region shown in FIG. 3 in order to explain the above phenomenon. When vertical 1ift electric cocoon transfer electrodes 21 and 22 and horizontal electric ring transfer electrode 27 are on, vertical transformer 7 agutotokikan 23
The first-place distribution at the time when the horizontal shift register 12 is turned off is shown in descending order of the amount of transfer power in the horizontal shift register 12. Further, FIG. 5 shows the actual measurement results showing the relationship between the amount of transferred charge and the non-transfer efficiency in the horizontal shift register 12. The measurement was carried out when the channel width W of the region 30 shown in FIG. A charge transfer imaging device is used in which the channel region 24 has a 411 W M of 30 μm.

Hereinafter, the above phenomenon will be explained using FIGS. 2, 3, 4, and 5.

First, since the channel width Wv of the region 30 shown in FIG. 2 is smaller than the channel width WM of the channel region 24 of the horizontal shift lens, the channel width Wv of the region 30 shown in FIG.

The channel potential φvL of the region 36 in (c) becomes smaller than the channel potential φ□ of the region 37 due to the narrow channel effect. Therefore, as shown in FIG. 4 (1), when a signal charge of a level smaller than the channel region 37t of the horizontal shift lens star - the above two channel potential differences φ, -φ7 is transferred, 36, and efficient transfer is performed. However, the same figure (
As shown in b), when the level of the signal charge to be transferred becomes so large as to exceed the potential difference φyaw φ9, a portion of the signal charge enters the region 36, significantly deteriorating the transfer efficiency of the horizontal shift lens. This is the cause of the horizontal movement of the image of the subject's vagina, which is a luminance subject, and the blurring of the replay image on the right side of the TV screen, as mentioned above.

Therefore, these phenomena tj! In order to reduce the incident light '1k to 1! By II II,
The maximum signal charge level to be photoelectrically converted is shown in Figure 4 (1).
As shown in the figure, it is necessary to limit the channel potential difference φyaw to be smaller than φ9. However, according to the fruitful IJ results in Figure 5, the range with good transfer efficiency as described above is within range 1 in the figure.
! As shown in iIK, the amount of transferred electrococoon is about 0.005 pC,
The output signal voltage is limited to a narrow range of about 200 mV, and a sufficient dynamic range cannot be obtained. This problem cannot be corrected and becomes a cause of not being able to obtain a high signal-to-noise ratio for the entire charge transfer imaging device. Next, when a signal electric image of a higher level than the one shown in FIG. 4 (b1) is transferred in the horizontal shift register,
The transfer efficiency in the case of figure (c) is the effect of bias charge rC
This is better than the case shown in Figure 4 (b). The transfer efficiency improvement effect due to this bias vlL is shown in Figure 5, 6g.
It is also clearly shown in the range ■ of ll16 fruits. However, in the conventional charge transfer imaging device shown in Fig. 1, since the photoelectrically converted signal charge has image information from the zero level, Fig. 5 shows the disadvantageous transfer efficiency improvement effect of bias charge. cannot be expected.

For example, the number ' of 0, 1 OpC obtained by photoelectric conversion
Considering the case where song a is transferred through a horizontal shift lens, this signal electric image is also affected by the area of transfer vehicle deterioration shown in range I in Fig. 5, so that some components of the electric image are inevitably left behind. . However, photoelectric conversion
Although it is possible to obtain the effect of a bias charge by irradiating with a bias 9 that generates pC5aco electric violet, the deterioration of the signal-to-noise ratio in this case is practical and cannot be underestimated.

An object of the present invention is to provide a novel method for driving a charge transfer imaging device that eliminates such drawbacks.

According to the present invention, a plurality of rows of vertical shift register groups formed on the same substrate are formed of iI double speed transfer devices, a photoelectric conversion element group arranged corresponding to the vertical shift register group, and the! l! A horizontal transfer register provided in contact with one end KM of the mountain shift register group and a channel region at the end of the vertical shift register group are provided by covering with a part of the horizontal electric brass transfer mechanism of the horizontal shift register group. a coupling part between the vertical shift register group and the front water distribution half shift register; a charge detection part provided at one end of the horizontal shift register; and an input part provided at the other end of the horizontal shift register. Biru Kamishin Transfer *
In the driving of the seal, the above-mentioned horizontal Kamebi Tikomi Kamebyo is #I! *
f in the potential well of the front 1@ joint formed when the
#A method for driving a KM transfer imager is obtained, characterized in that the amount of the bias electric current is set such that the bias electric current injected from the electric power unit penetrates.

Next, an actual example of the present invention will be explained using the drawings.

The structure of the IIL load transfer linkage device necessary to carry out the present invention is as shown in FIG. 6, and the conventional horizontal shift register 12 shown in FIG. Just that is enough. In Figure 6 Kli, the number 4#, which is the same as No. 1, indicates the same box formation fee.

Also, 'II1.' of such a structure. Since the operation of the I-transfer photographing arrangement is similar to that of the conventional example shown in FIG. 1, here we will briefly explain the process of transferring the turtle hook in the 8AK-related stock horizontal shift lens star.

The feature of the driving method of the ``IIL transfer transfer'' according to the present invention is that a constant amount of bias is always injected from the 4-mass M input section 60 to the horizontal shift register 12 as shown in FIG. . Here, as a method for injecting the 'ik song from Q, the minute hand engineer should use any of the following methods: tiode force, tooff method, noodles, can-pei method, etc. May be used. Also, inject bias electricity L, elephant,
The bias tm is used to set both the range 1 and the range l of the sludge results in FIG. For example, in the case of FIG. 5, the optimum bias charge amount is 0.059C.

FIG. 7 is a diagram for explaining the driving method according to the present invention in detail, and similarly to the fourth example, the potential distribution in each part of the cross section of the coupling region shown in FIG. 3 is shown.

The vertical charge transfer electrodes 21, 22 and the horizontal charge transfer electrodes 27 are shown schematically at the time when they are in the on state and the vertical transformer 7 agoto electric shelf 23 is in the off state. In the same figure,
Reference numeral 70 denotes a bias charge injected from the above-mentioned %cocoon input section 60, and a state in which both the 5-th range lhI and the range l are filled with bias electric charges is shown. At this time, a bias electric image also exists under the area 36. Further, in the same figure, 71 is photoelectrically converted by the photoelectric conversion cable 11,
Vertical shift register pi O? : The signal is transferred to the horizontal shift register 12 via the bias voltage 70, and is stored in both areas 36 and 37 along with the bias voltage 70.
According to the above operation, the transfer of the signal on the horizontal shift lens is always carried out in the range l shown in 5-5 of the transfer video, which is the same as in the conventional drive method. The horizontal flow of the TV - Tartar side playback i! My first mistake is completely preventable. Furthermore, as shown in the actual alignment results in Figure 5, the dynamism and range of the horizontal shift lens star is very small at about 200 mV in the conventional drive method using the range l, but it is very small at about 200 mV. In the driving method of the present invention using IIm, the driving speed is about 2 mm, which is 10 mm compared to the conventional example.
Improved by almost twice as much. Furthermore, in the present invention, the bias voltage at-
Because the injection is done purely electrically, there is no uneven irradiation, false spots, or Kerr shadows compared to the conventional method, which generates bias charges by irradiating the entire photoelectric conversion region with a bias source. It also causes less deterioration of the signal-to-noise ratio of the entire transfer chest apparatus. In the present invention, the most effective hint is to optimally meet the child of Bahia x Electrician, but according to the experiment by the inventor of Book 4+#, the turtle #4 in Figure 5
The curve of the graph showing the relationship between the lid and the non-transfer efficiency does not vary from chip to chip unless device parameters such as channel length and channel width or process conditions change. Furthermore, the amount of bias electricity can be adjusted by the charge input section 6.
This can be easily done by changing the DC bias voltage applied to zero.

As described above, according to the present invention, the horizontal flow of the video and the right side of the TV screen! It is possible to obtain a method for driving an electronic image transfer m-image device koji that does not generate 4-6 images and can have a wide dynamic range.

It should be noted that the present invention will be described here as an example of an interline transfer method.
Although the explanation was given using a transfer camera, it can be similarly achieved using a 7-rem transfer system.

[Brief explanation of the drawing]

Figure 1 shows an image capture device using the interline transfer method.
Figure I, Figure 21 is an enlarged view of the coupling area of the vertical 1 shift register and horizontal shift register in Figure 1, and Figure 3 is the 2nd #
FIG. 4(1) is a cross-sectional view of IA along line 1-1. lb) @ tc) is a schematic diagram showing the potential distribution and transfer voltage value at each point in FIG. 3, and shows the conventional driving method. In addition, @5111 is the result showing the relationship between the transfer mechanism @ lid and non-transfer efficiency in a horizontal shift lens star, and Figure 6 is a schematic diagram of an interline transfer type imaging device equipped with a charge input section necessary for implementing the present invention. , FIG. 7 shows the potential distribution at each point in FIG. 3 and gM-1! when the driving method according to the present invention is used. It is a schematic diagram which shows the state of an electric back and a bias charge. In the figure, 1O is a vertical shift register group, 11 is a photoelectric conversion element group, 12 is a horizontal shift register, 13 is a charge detection unit, 14 is a coupling area between the Fil direct shift lens and horizontal shift lens, 20 is a channel area of the vertical shift register, 21. 22 is a vertical charge transfer electrode, 23 is a vertical transfer gate [4, 24, 37Fi channel region of horizontal shift register, 25 to 29 are horizontal charge transfer electrodes, 30
゜36 is the end area of the vertical shift register covered with a part of the horizontal '1IlcW1 transfer%-, 311i half-width board,
32 is an insulating layer, 33 is an indentation channel riser, 34 is a channel stop region, 35 is a metal layer, and 60 is a charge input portion. Daiken fF deceased Atsushi Uchi Atsushi Ashi Figure 1 Figure 2 Figure 3 Cα) 34 37 36 37 36 3 Figure 5 Yo 1 Rikiden J Gohi (V) Figure 6 Figure 7 Pavilion 37

Claims (1)

[Claims] A plurality of rows of stacked shift register groups formed on a Toj-substrate including charge transfer devices, a photoelectric conversion element group arranged corresponding to the vertical shift register group, and adjacent to one end of the vertical shift register group. The charge transfer horizontal shift register provided at the front and the end of the front vertical shift register group
The channel area of the horizontal '#L' of the horizontal shift register is
Transfer 11 - Prepared by soaking with vinegar II
A connecting part between a group of vertical shift registers and the water shift register, a telegraph detection part installed at one end of the horizontal shift register, and one installed at the other end of the horizontal shift register. In the driving of the turtle transfer imaging device consisting of the load input part, the potential well of the coupling part formed when the horizontal '1Kf+1 transfer electric current is &
A method for driving a telegraph transfer imaging device in which the special mission is to set the amount of bias charge so that the bias charge injected from the sacral input section enters the Fl'll arrangement.