JPH0834567B2 - Solid-state imaging device and driving method thereof - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solid-state image pickup device that can be used in an image pickup portion such as a video camera.

2. Description of the Related Art In recent years, most solid-state image pickup devices have been replaced with image pickup tubes in the consumer field as image pickup elements for video cameras, and their performance has been improved. Among them, the FIT type solid-state imaging device (Frame-Interlin
e Transfer Carge-Coupled Device) has excellent characteristics and is under active development.

Hereinafter, the conventional solid-state imaging device as described above will be described with reference to the drawings.

FIG. 5 is a schematic diagram of a conventional solid-state imaging device. Fifth
In the figure, 1 is a photodiode for photoelectric conversion, 2 is a readout gate for reading out optical signal charges generated in the photodiode, 3 is a vertical transfer section, 15 is an accumulation section, 16 is a horizontal transfer section, 17 is an output section, and φV _{1 , 2} are transfer pulse application terminals, φ _PT
Is a read pulse application terminal. FIG. 6 is a drive pulse timing chart of a conventional solid-state imaging device. In FIG. 6, φ _PT is a read pulse and φ V _1,2 is a transfer pulse.

The operation of the solid-state imaging device configured as described above will be described below.

First, in the period of t ₁ , the vertical transfer unit 3 and the storage unit 15 are driven at high speed, and smear charges are sent to the horizontal transfer unit 16 and swept out. Next, at t ₂ , a pulse is applied to the read gate 2 by φ _PT to read the signal charge. After that, the signal charges are transferred at high speed during the period of t _{3 and} are accumulated in the accumulating unit 15. Then t ₄
During the period, the signals of the storage unit 15 are sequentially read and output.

However, in the above-described structure, the current wafer processing technology can arrange only about 250 vertical transfer stages for about 500 photodiodes in the vertical direction. Therefore, the signal charges of two adjacent rows cannot be transferred independently, and 1
Must be mixed and transferred. Therefore, although the photodiode section obtains high resolution in the vertical direction, there is a drawback that the resolution is deteriorated by mixing in the vertical transfer section. In view of the above-mentioned drawbacks, the present invention provides a solid-state imaging device capable of independently outputting signal charges generated by photodiodes without mixing them, and a driving method thereof.

Means for Solving the Problems In order to solve the above problems, in the solid-state imaging device of the present invention, a light receiving section in which light receiving elements are arranged in a two-dimensional manner and a signal charge generated in the light receiving section are vertically A vertical transfer section for transferring the signal charge to the vertical transfer section from the light receiving section, first and second storage sections for temporarily storing the signal charge, and A first storage unit and a second storage unit for transferring signal charges to each other, and the transfer gate unit is driven to transfer the signal charges from the second storage unit to the second storage unit. A first storage unit transfer pulse input to the transfer gate unit and a second storage unit transfer pulse input to the first storage unit, respectively. The second input terminal and the signal charge are forwarded from the first storage unit. A first shift register for transferring to the second storage unit, a second shift register for driving a plurality of rows of the second storage unit, and first and second horizontal registers for transferring the signal charges in the horizontal direction. The transfer method includes a transfer section and first and second output sections, and a driving method thereof is to transfer the signal charges read every other row from the light receiving section to the second storage section by a vertical transfer pulse. After that, the first storage section transfer pulse is input from the first input terminal and the second storage section transfer pulse is input from the second input terminal to transfer the first storage section transfer pulse to the first storage section. The remaining signal charges are read from the light receiving unit and transferred to the second storage unit, and the signal charges selected by the second storage unit are transferred to the first storage unit by the first shift register.
And vertical transfer in the second storage unit including a second horizontal transfer unit, and transfers the signal charge selected in the first storage unit by the first shift register to the second storage unit. By doing so, one signal charge is transferred from the second storage section to each of the first and second horizontal transfer sections during one horizontal blanking period, and the first and second signal charges are further transferred within one horizontal period. In the horizontal transfer section, and read independently from the first and second output sections.

Action With this configuration, the signal charge generated in the light receiving element is
The signal charges in the even-numbered rows and the signal charges in the odd-numbered rows can be separated and independently transferred and read without being mixed.

Embodiment One embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic diagram of a solid-state image pickup device according to an embodiment of the present invention. Reference numeral 1 is a photodiode for photoelectric conversion, 2, 2'is read gates of odd and even rows for reading the signal from the photodiode 1, 3 is a vertical transfer unit for vertically transferring the read signal charges, and 4 is a vertical transfer unit. Even (odd)
A first storage unit for temporarily storing signal charges of several rows, a second storage unit for temporarily storing signal charges of odd (even) rows,
6 is a storage unit transfer gate that transfers the signal charges stored in the first (2) storage unit 4 (5) to the second (1) storage unit 5 (4), and 7 is one row of the storage unit transfer gate 6. , 8 is a vertical shift gate unit for transferring signal charges existing in the second storage unit 5, 9 is a second shift register for driving a plurality of rows of the vertical transfer gate unit 8, 10 is a reset gate for resetting the second shift register 9, 11 is a first horizontal CCD for an even (odd) number of rows, 12 is a second horizontal CCD for an odd (even) number of rows, and 13 is an even (odd) number. A first output section for rows and a second output section 14 for even (odd) number of rows. φ
_PT1 is a terminal for applying a read pulse for reading out signals of odd (even) rows, φ _PT2 is a terminal for applying a read pulse for reading out signals of even (odd) rows, φV ₁ to ₄
Is the terminal that applies the vertical transfer pulse, and φ _MT1 and φ _MT2 are the second
(1) A terminal for applying a pulse for transferring a signal charge from the storage unit 5 (4) to the first (2) storage unit 4 (5), φ _R
Is a terminal for applying a reset pulse, φ _SR1 is a terminal for applying a pulse for the first shift register, and φ _SR2 is a terminal for applying a pulse for the second shift register. FIG. 2 is a driving pulse timing chart of the solid-state imaging device according to the embodiment of the present invention. In FIG. 2, φ _PT1 is an odd-row readout pulse, φ _PT2 is an even-row readout pulse, φV ₁ to ₄ are vertical transfer pulses, φ _{MT1 and 2} are storage section transfer pulses, and φ _SR1 is the first pulse.
A shift register pulse, φ _SR2 is a second shift register pulse, and φ _R is a reset pulse.

The operation of the solid-state imaging device configured as described above will be described below. First, when t (time) = t ₁ , φ
_A read pulse is applied from _PT2 to the read gates _2'of even-numbered rows to read signal charges. After that, in the period of t _2, the signal charges are transferred to the second storage unit 5 by the transfer pulses φV ₁ to ₄ . Thereafter, as shown in FIG. 3, signal charges are transferred from the second storage section 5 to the first storage section 4 from φ _MT1,2 and stored. Next, when t = t ₇ , a read pulse is applied from φ _PT1 to the read gates 2 in odd rows to read signal charges.
Then transfer period t ₈ pulses .phi.V ₁ ~ ₄ the signal charges transferred to the second storage unit 5, previously accumulated. The above operation is performed within the vertical blanking period, and when the operation is completed, the signal charge is
It is accumulated as shown in FIG.

Next, at t = t ₉ , the first vertical transfer gate unit 8 from φ _SR2
To transfer the signal charge Q ₁ to the first horizontal CCD 11 (FIG. 4b). At t = t ₁₁ , the first storage unit transfer gate 6 is turned on from φ _SR1 to transfer the signal charge Q ₂ to the adjacent second storage unit 5 (FIG. 4c). At t = t ₁₂ , the first to second vertical transfer gate portions 8 from φ _SR2 are driven to sequentially transfer the signal charges Q ₁ , Q ₂ and Q ₃ downward (step d in FIG. 4). At t = t ₁₃ , the second storage unit transfer gate 6 is turned on from φ _SR1 to transfer the signal charge Q ₄ to the adjacent second storage unit 5 (FIG. 4e). After that, in the horizontal period, the signal charges Q ₁ and Q ₂ are independently transferred to the horizontal transfer units 11 and 12.
And are read out simultaneously from the output units 13 and 14. The following are sequentially read out in the same manner as in the third row of the signal charges Q ₃ and fourth row of the signal charges Q _4, 5 and sixth lines ... (Fig. 4 f, g, h, i) .
A reset pulse for resetting the second shift register is applied by φ _R after the field transfer.

As described above, according to this embodiment, the signal charges of the photodiodes for two rows can be independently read during one horizontal period.

As described above, according to the present invention, the signals of the photodiodes can be read out without being mixed, the resolution in the vertical direction can be increased, and the practical effects thereof are great.

[Brief description of drawings]

FIG. 1 is a schematic diagram of a solid-state imaging device according to an embodiment of the present invention, FIG. 2 is a drive pulse timing diagram of the solid-state imaging device according to the embodiment of the present invention, and FIG. 3 is a solid-state imaging device according to the embodiment of the present invention. FIG. 4 is a schematic diagram showing how signal charges are transferred from the second storage section to the first storage section. FIG. 4 is a schematic diagram showing how signal charges are transferred in the storage section of the solid-state imaging device according to the embodiment of the present invention. FIG. 5 is a schematic diagram of a solid-state image pickup device in the conventional embodiment, and FIG. 6 is a drive pulse timing diagram of the solid-state image pickup device in the conventional embodiment. 1 ... photodiode, 2,2 '... readout gate,
3 ... Vertical transfer unit, 4 ... First storage unit, 5 ... Second storage unit, 6 ... Storage unit transfer gate, 7 ... Storage unit transfer gate driving shift register, 8 ... Vertical transfer gate unit , 9 ...
... Vertical transfer gate driving shift register, 10 ... reset gate, 11 ... first horizontal CCD, 12 ... second horizontal CCD,
13 ... 1st output section, 14 ... 2nd output section, 15 ... storage section,
16 …… Horizontal CCD, 17 …… Output section.

Claims (3)

[Claims] 1. A light receiving section in which light receiving elements are arranged two-dimensionally, a vertical transfer section for vertically transferring signal charges generated in the light receiving section, and a signal charge from the light receiving section to the vertical transfer section. A readout gate unit for reading, first and second storage units for temporarily storing the signal charges, and signal charges for the first storage unit and the second storage unit And a transfer gate unit for transferring the signal charges from the second storage unit by driving the transfer gate unit.
First storage section transfer pulse input to the transfer gate section and second storage section transfer pulse input to the first storage section for transfer to the second storage section Input terminal, a first shift register that transfers the signal charge from the first storage unit to the second storage unit, and a second shift register that drives a plurality of rows of the second storage unit. And a first and a second horizontal transfer section for transferring the signal charges in the horizontal direction, and a first and a second output section. 2. The solid-state image pickup device according to claim 1, wherein the first storage portions and the second storage portions are alternately arranged in a row. 3. A light receiving section in which light receiving elements are arranged two-dimensionally, a vertical transfer section for vertically transferring the signal charges generated in the light receiving section, and a signal charge read from the light receiving section to the vertical transfer section. The read gate unit, the first and second storage units for temporarily storing the signal charge, and the first and second storage units mutually store the signal charge. A transfer gate section for transferring, and a first input to the transfer gate section for driving the transfer gate section and transferring the signal charge from the second storage section to the first storage section. First and second input terminals to which a storage unit transfer pulse and a second storage unit transfer pulse to be input to the first storage unit are respectively input; and the signal charge from the first storage unit to the first storage unit. A first shift register for transferring to the second storage unit;
A second shift register for driving a plurality of rows of the second storage section; first and second horizontal transfer sections for horizontally transferring the signal charges; and first and second output sections. After transferring the signal charges read out from the light receiving section every other row to the second storage section by a vertical transfer pulse, the first storage section transfer pulse is transferred from the first input terminal to the second storage section. The second storage unit transfer pulse is input from the input terminal and transferred to the first storage unit, and then the remaining signal charge is read from the light receiving unit and transferred to the second storage unit, Shift register vertically transfers the selected signal charges of the second storage unit in the second storage unit including the first and second horizontal transfer units, and the first shift register transfers the selected signal charge in the vertical direction. The selected signal charges of one storage unit By transferring 2 to the storage unit,
One signal charge is transferred from the second storage unit to each of the first and second horizontal transfer units during one horizontal blanking period, and the first and second horizontal transfer units are further transferred within one horizontal period. Is transferred in the horizontal direction and read independently from the first and second output sections.