JPH0342540B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for driving a solid-state imaging device, and more specifically to a linear array sensor in which light-receiving elements are arranged in a line, and a method for driving a solid-state imaging device. The present invention relates to a method for driving a solid-state imaging device including a charge transfer section that drives and transfers charges in main scanning and outputs them as time-series signals, and a sub-scanning mirror.

Generally, in fields that require high-resolution visible images, a long sensor such as a CCD linear sensor that combines a CCD and a linear array sensor is used. Performs mechanical scanning. This mechanical scanning becomes the sub-scanning of the imaging device. A case will be described below in which a vibrating mirror is used for sub-scanning and its motion is a sinusoidal function.

FIG. 1 is a conceptual diagram of the main parts showing an example of the structure of a visible long sensor consisting of a linear array sensor and a charge transfer section, in which 1' is a light-receiving element, and each light-receiving element 1' is a line The linear array sensors 1 are arranged in the form of a linear array sensor 1. Further, a charge transfer section 2 shown largely surrounded by a dashed line is provided adjacent to the linear array sensor 1, and the charges photoelectrically exchanged in each of the light receiving elements 1' pass through each charge storage region 3'. The charges are transferred directly below the transfer electrode 4 or 5, and the transferred charges are driven and transferred in main scanning and are output from the output terminal CUT as a time-series signal.

FIG. 2 is a conceptual diagram of main parts showing the configuration of a solid-state imaging device consisting of a combination of a visible long sensor and a sub-scanning vibrating mirror as described above. It is reflected by a mirror 6, passes through a lens 7, and forms an image on a linear array sensor of a long sensor 8. At this time, the sub-scanning vibrating mirror 6 is moved to the intersection 9.
It performs sub-scanning by repeatedly rotating around , performing sinusoidal motion.

By the way, for a sub-scanning vibrating mirror that moves in a sinusoidal manner, if the drive of a long sensor, that is, the main scanning period, which is normally performed, is constant, the left and right edges of both sides of the display (usually a long sensor Since it is arranged vertically and sub-scanning is performed in the horizontal direction, the image (as seen from the center of the sub-scanning field of view toward left and right repeating points) is expanded. Conventionally, as a countermeasure for this, image distortion has been corrected by increasing the scanning line density at the left and right peripheral portions of the display screen and displaying the image in a reduced size by the amount of expansion. In addition to correcting the image distortion described above, this correction also includes a brightness correction that suppresses this and makes the brightness distribution uniform over the entire screen, since the average brightness of the left and right edges of the display screen increases as the scanning line density increases. accompany. Since the scanning line density is changed within the display screen in this way, the resolution differs within the screen, and this is coarse in the center of the screen and dense at the left and right edges, creating a visual discomfort. There are also drawbacks, such as the fact that the device configuration becomes complicated because the two corrections are to be made for image distortion and brightness.

The present invention has been made in view of the above-mentioned points, and its purpose is to control the scanning line spacing of an imaging screen in an imaging device consisting of a sub-scanning vibrating mirror that moves in a sinusoidal manner, a linear array sensor, and a charge transfer section. The purpose of the present invention is to provide a driving method for a solid-state imaging device that eliminates visual discomfort by keeping the image constant.
Charge transfer in which charges are transferred from an array sensor and each light receiving element of the linear array sensor, and the transferred charges are driven and transferred by an electrical signal for main scanning to output as a time series signal. In the solid-state imaging device, the charge transfer unit is driven at both ends of the sub-scanning period in response to the movement of the sub-scanning mirror. This area is made longer than the central part so that the main scanning line interval of the captured image is constant.

Embodiments of the present invention will be described below with reference to the drawings.

FIGS. 3a, b, and c are conceptual diagrams for explaining the driving method of a solid-state imaging device according to the present invention, and FIGS. 4a, b, and c are conceptual diagrams showing a conventional driving method for a solid-state imaging device. On both sides, a indicates the deflection angle with respect to time of the sub-scanning vibrating mirror that moves in a sinusoidal manner, b indicates the main scanning, that is, scanning in the Y direction, and c corresponds to the scanning of a and b. FIG. 3 is a diagram illustrating scanning lines on an image capture screen that appear on the screen.

First, referring to FIG. 4, as is clear from the figure, in the conventional driving method, the main scanning period t is kept constant, so the interval between each scanning line l appearing on the imaging screen is Large X in the center of the screen
It becomes smaller in the direction, that is, toward the left and right edges of the imaging screen. On the other hand, as is clear from FIG. 3, in the driving method according to the present invention, the main scanning period t is
is not constant, but the main scanning period t is variable so that the interval between each scanning line l of the imaging screen is constant,
The main scanning period t at the left and right peripheral portions of the imaging screen, where the sub-scanning speed is slow, is made sequentially longer than the central portion of the screen. Note that when changing the main scanning period t, the shape of the "sawtooth" wave for scanning is the same as in the conventional method, and the to period of the main scanning period t is made variable.

By the way, the number of stages of charge transfer electrodes 4 and 5 in the charge transfer section of a long sensor as shown in FIG. It has a number of transfer stages, and also performs so-called "empty" transfer in which only the transfer operation is performed in a state where there is no charge. In the present invention, as described above, as a means for changing the main scanning period t by adjusting the to period of the main scanning period t, a method of adjusting the time from the transfer is introduced. .

FIG. 5 is a timing chart showing the driving signals applied to each bus line of the charge transfer unit in the long sensor shown in FIG. indicates the period,
to is a period corresponding to the so-called "from" transfer time for changing the main scanning period t (see FIG. 3). In other words, when varying the main scanning period t according to the deflection angle of the sub-scanning vibrating mirror, the output signal (OUT)
The main scanning period t is changed by adjusting the to period in which the t is not output. The charges photoelectrically converted in each light receiving element 1' as shown in FIG. 1 are accumulated in each charge accumulation region 3' at timing tG, and the accumulated charges are accumulated at timing tT.
The transferred charges are transferred directly below the charge transfer electrode 4 connected to the bus line φ1, and the transferred charges are sequentially transferred and output as a time-series signal from the output terminal OUT. Here, RS is a reset pulse for reading.

As is clear from FIG. 5, when the main scanning period t is varied, the charge accumulation time must always be kept constant, so it goes without saying that the timing tG at the accumulation gate BG should always be kept constant. . Although not shown in the figure, in a period other than the timing tG, a charge discharge gate disposed adjacent to the linear array sensor 1 on the opposite side of the charge transfer section 2 in FIG. What is necessary is to discharge the unnecessary charges photoelectrically converted in each light receiving element 1' during a period other than the above period.

Next, FIG. 6 shows a block diagram showing the configuration of a drive circuit for generating the drive signal shown in FIG. 5. The timing of the drive signal shown in FIG. 5 is written in the programmable read-only memory P-ROM 2 according to the contents indicated by the counter 1. Counter 1 is a variable counter, and a certain 1
Outputs an RC signal as a signal to indicate that counting has been completed for the number of times corresponding to the main scanning period,
In accordance with the RC signal, the counter control section outputs an EN signal to the counter 2 and increments the contents of the counter 2 by 1. and counter 2
The contents of are input to the programmable read-only memory P-ROM1. P-ROM1
A value indicating the number of clocks for the main scanning period shown in FIG. 3, that is, the number of clocks CLK that enters the period t shown in FIG. 5, is written in . Further, the counter 2 counts the number of main scanning lines. Then, the counter control section generates the LD signal and controls the counter 1 according to the contents of P-ROM1.
Load. In this way, the counter 1 becomes a variable counter, and its contents are scanned at the timing shown in FIG. 5, and as the contents are counted up, the contents shown in FIG. A drive signal will be output from P-ROM2. Note that the scanning in the Y direction shown in Figure 3b is repeated once per frame,
The FRM signal is a signal synchronized with this frame and is input to the counter control unit once per frame. A clear pulse CLR is generated at the same rate in response to the FRM signal, and clears the counter 2 every frame. Also, CLK is a clock pulse.

In the above-mentioned embodiment, a driving method was described in which the transfer operation is performed "from" the to period in order to make the main scanning period t variable. Yes, and the charge transfer electrode does not necessarily have a two-phase configuration.
In general, it is of course possible to have an N-phase configuration where N is a natural number. Furthermore, it is not necessary to arrange the light-receiving elements in a straight line; for example, they can be arranged in a staggered manner. It is also clear that the present invention can be developed and realized using exactly the same procedure for a vibrating mirror whose motion is represented by an arbitrary function.

As is clear from the above description, according to the present invention, the scanning line interval on the imaging screen can be made constant in a solid-state imaging device using a long sensor and a sub-scanning vibrating mirror that repeatedly rotates. A display screen that does not give a visually strange feeling can be obtained, and since only one type of correction is required compared to conventional methods, the device configuration can be simplified and the device can be made smaller, which has great practical effects. It is.

[Brief explanation of drawings]

Fig. 1 is a conceptual diagram of the main parts showing the structure of an example of a long sensor that is a combination of a linear array sensor and a charge transfer section, and Fig. 2 is a solid-state image pickup using a long sensor and a sub-scanning vibrating mirror. FIG. 3 is a conceptual diagram of the main parts showing the configuration of the device, and FIG. 3 is a diagram for explaining the driving method of the solid-state imaging device according to the present invention. FIG. 4 is a diagram showing the scanning of the main scanning, and c is a diagram showing the scanning lines of the imaging screen corresponding to the scanning of a and b. FIG. 4 explains the driving method of the conventional solid-state imaging device. Fig. 2 is a diagram showing the deflection angle of the sub-scanning vibrating mirror with respect to time, which moves in a sinusoidal manner, b is a diagram showing the main scanning, and c is a diagram showing the main scanning.
5 shows the scanning lines of the imaging screen corresponding to the scanning of a and b, and FIG. 5 shows the drive signals applied to each bus line of the charge transfer unit shown in FIG. The corresponding timing chart and FIG. 6 are block diagrams showing one example of a drive circuit configuration for generating drive signals for a solid-state imaging device according to the present invention. 1': Light receiving element, 1: Linear array sensor,
2: Charge transfer section, 3': Charge storage region, 4, 5:
Charge transfer electrode, 6: sub-scanning vibrating mirror, 8: long sensor, t: main scanning period, l: scanning line of the imaging screen.

Claims (1)

[Claims] 1 A linear array sensor in which a plurality of light receiving elements are arranged in a line, charges are transferred from each light receiving element of the linear array sensor, and the transferred charges are driven by electrical signals for main scanning. In a solid-state imaging device, the solid-state imaging device is equipped with a charge transfer unit that outputs a time-series signal by transferring the charge, and a sub-scanning mirror that rotates back and forth. A method for driving a solid-state imaging device, characterized in that the main scanning period for driving the charge transfer section in the central portion is longer than that in the central portion so that the main scanning line spacing of the imaging screen is constant.