JPS63242071A - Image pickup element of dimmer type for each picture element - Google Patents

Abstract

PURPOSE:To obtain a pickup pattern in which an original picture is not deteriorated by applying a command voltage obtained from an image pickup signal to a transparent film arranged onto a photodetection face of a photosensing section from a transmission quantity control section so as to control the quantity of transmission of an incident light to the transparent film by each picture element depending on the quantity of the command voltage. CONSTITUTION:An address of a picture element of an excess incident light stored in an address decoder 19 and a control data stored in a data decoder section 21 are inputted to the transmitted light quantity control section 9 corresponding to the picture element as a command signal by a distribution gate 23. Thus, in applying a voltage to an electrode 8a of the transparent film 8 from the transmitted light quantity control section 9, since the chemical substance 8c of the transparent film base 8b is changed in proportion to the command voltage in its arranging state, the transmittivity of the incident light 8d is changed and it is possible to control so as to give a proper incident luminous quantity to all photodiodes 4. Thus, a pickup pattern with good quality is obtained even from a picture having a large difference in the luminous quantity distribution from a metallic glitter work very close to the mirror face reflection.

Description

[Detailed Description of the Invention] [Objective of the Invention] (Industrial Application Field) The present invention is an optical semiconductor for detecting the position of incident light using an array of MO8 type capacitors with electrodes attached on the surface of a semiconductor substrate, a so-called CCD image. This invention relates to an improvement of a pixel-specific light control type m-image element of a sensor.

(Prior Art) The photosensitive area for incident light in a conventional CCD image sensor is composed of a photodiode, a storage electrode using an MO8 capacitor, and a shift electrode, and the shift electrode is turned on and off to determine the accumulation time of the signal after photoelectric conversion. By controlling the
The image was electrically generated by adjusting the incident light.

However, when using such a conventional CCD image sensor to image an industrial workpiece, for example, the industrial workpiece generally has a metallic luster close to a specular reflection, and moreover, the reflected illumination light is only partially directly received. Because there are many
There is a photosensitive area where the amount of photoelectric conversion is saturated, and it is difficult to capture an image without saturating the light reception signal over the entire light reception surface.

In addition, in order to eliminate saturation of the photoelectric variation calibration, it is possible to narrow down the amount of light incident on the photodetector until image information of the halation area is obtained in a localized area, but in this way, C
Since the light receiving amount range of brightness and darkness allowed by the OD image sensor is narrow, there is a problem in that, contrary to the above, image information of peripheral dark areas cannot be obtained.

(Problems to be Solved by the Invention) In this way, when imaging a modern glossy workpiece with a COD image sensor, there may be a photosensitive area where the photoelectric variation calibration is saturated, or conversely, if the amount of light incident on the light receiving element is narrowed down. There was a problem in that image information for dark areas could no longer be obtained, resulting in these areas becoming completely black. In computer technology, in any of the above cases, the inability to obtain image information from the entire light-receiving screen is a major problem as it is a fundamental obstacle to image processing.

The purpose of the present invention is to appropriately compress the distribution of the incident light amount so that it falls within the light receiving amount range of the COD image sensor and so that the original image is not damaged. It is an object of the present invention to provide a pixel-by-pixel dimming type ms element that can obtain image information of a signal level suitable for image identification from the entire light receiving screen without causing a portion.

[Structure of the Invention] (Means for Solving the Problems) In order to achieve the above object, the present invention includes a photosensitive section that photoelectrically converts incident light for each pixel and accumulates it as a signal charge, and a light receiving section of the photosensitive section. a transmission film arranged for each pixel on the surface and capable of controlling the amount of transmitted light transmitted according to the magnitude of an applied voltage; and a transfer section that scans and transfers signal charges accumulated in the photosensitive area for each pixel. , a floating diffusion layer section into which the signal charge transferred by this transfer section is injected, and a conversion section that converts the signal charge injected into this floating diffusion layer section into a voltage and outputs it as an imaging signal to an external image processing section. and a transmission-b for controlling the amount of incident light transmitted through the transmission film disposed on the light-receiving surface of the pixel using a command voltage obtained from the output voltage of the conversion section.
It is characterized by having a J'a section.

(Function) In the pixel-by-pixel dimming type image pickup device having such a configuration, a command voltage obtained from an image signal is applied from the transmission amount control unit to the transmission film disposed on the light-receiving surface of the photosensitive section. Since the amount of incident light transmitted through the transmission film is controlled for each pixel according to the magnitude of the command voltage, the entire imaging screen is kept at a signal level suitable for image identification, and the original image is not damaged. It becomes possible to obtain an m-image screen without any problems.

(Practical example) An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows an example of the overall configuration of a pixel-based light-adjustable image carrier according to the present invention, and FIG. 2 shows an example of the basic structure of its light-receiving pixel. In FIGS. 1 and 2, 1 is a package, and on the front surface of this package 1, a large number of light-receiving pixels 2 are arranged vertically and horizontally like the grid of an M board, forming a light-receiving surface 1a. . Each of these light-receiving pixels 2 has a photodiode 4 which is provided through an insulator 11I13 formed on the surface of the semiconductor and serves as a photosensitive area for incident light, and temporarily converts the electric signal converted by the photodiode 4 into a signal charge 6. It consists of a storage electrode 5 based on the MO8 capacitance that accumulates in the photodiode 3, and a transmitting lI8 which is connected to the light receiving surface of the photodiode 3 via an insulating film 3 and whose amount of transmitted light can be controlled according to the magnitude of the applied voltage. As shown in FIGS. 3 and 4, this transmission 1!18 consists of a transmission membrane base material 8b and electrode portions 8a provided on both sides thereof, and when a voltage is applied between these electrodes 1188, an optical substance 8C is applied. For example, it is something like a liquid crystal that is attracted to a voltage and changes the degree of alignment and changes the amount of transmitted light, and the amount of transmitted light is proportional to the magnitude of the applied voltage. Further, reference numeral 9 denotes a transmission amount control unit which is connected to the electrode 8a portion of the transmission film 8 for each pixel and applies a command voltage between the electrodes 8a;
operates in synchronization with the clock signal input through the vertical register clock terminal 11 and the horizontal register clock terminal 12, and operates in synchronization with the clock signal input through the vertical register clock terminal 11 and the horizontal register clock terminal 12, and the storage electrode 5 by the MO8 capacitor of each light receiving pixel 2
A COD analog shift register 13 sequentially shifts the signal charge 6 accumulated in the COD analog shift register 10, and 13 is a floating diffusion into which the signal charge 6 that has passed through the output gate 13 is temporarily injected. It is a floating capacitor consisting of layers. Furthermore, 16 is a MOS transistor section that converts the fluctuation of the signal charge 6 injected into the floating capacitor 15 into an output voltage, and the voltage converted by this MOS transistor 9 section 16 is passed through an output signal terminal 17 to an external image processing unit (not shown). It is designed to be output as an imaging signal to the section. Note that 18 is an output drain voltage terminal of the MOS transistor 9 section 16.

On the other hand, 19 is an address terminal 20 from an external image processing unit.
21 is a data decoder section that stores control data for the amount of transmitted light that is input from an external image processing section through a data terminal 22; The transmitted light amount control data stored in the data decoder section 21 corresponds to the address of the corresponding light receiving pixel stored in the address decoder 19. 23 indicates the pixel address stored in the address decoder 19 and the data decoder section 21
This is a distribution gate that supplies the control data stored in the transmitted light amount control section 9 as a command voltage to the corresponding transmitted light amount control section 9.

In the external image processing section mentioned above, the control amount for controlling the amount of light transmitted through the transmission film 8 with respect to the incident light on the light receiving pixel 2 is determined as follows.

When the image signal output from the MOS transistor 9 section 16 is given to an external image processing section, this image processing section first determines whether the imaging screen is too dark by setting an appropriate threshold level, and then If the brightness is too bright, increase the amount of illumination using an appropriate external lighting means, and conversely, identify whether there are any areas in the image capture screen that are too bright by setting an appropriate threshold level, and For each part, the pixel address and the control amount of the amount of transmitted light are calculated, and the pixel address is input to the address decoder 19 through the address terminal 20, and the control data is input to the data decoder section 21 through the data terminal 22. There is.

Next, the operation of the pixel-by-pixel light control type 11111 element configured as described above will be described.

When incident light hits the light-receiving surface 1a, this incident light is photoelectrically converted by the photodiode 4 of each light-receiving image R2, and the signal charge 6 is accumulated in the storage electrode 5. In this case, the shift electrode 7 is turned on and off to adjust the accumulation time tlIJtlD so that the exposure time becomes appropriate.

The signal charge 6 of each pixel accumulated in the storage electrode 5 is applied through the vertical register clock terminal 11 and the horizontal register clock terminal 12, and by turning on and off the shift electrode 7 in synchronization with the zero clock signal, the COD analog The signal is transferred to the register 10 and injected into the floating capacitor 15 based on the timing from the operation signal terminal 14 of the output gate 13. This 70-
When a signal charge is injected into the switching capacitor 15, the potential drop at that time is transferred to the source of the MOS transistor 9 section 16.
It is detected by the follower circuit and outputted from the output signal terminal 17 as an image signal to an external image processing section. Since the operating range of this output voltage is smaller than the fluctuation width of the incident light, some pixels may reach a saturation voltage. So, I! The m-image signal of the entire image screen is processed by an external image processing unit, and for pixels with excessive incident light that cannot be handled by turning on or off the shift electrode 7, the pixel address is stored in the address decoder unit 19 through the address terminal 20, Further, control data for the amount of transmitted light for each address is transmitted to the data decoder section 21 through the data terminal 22. The pixel address of the excessive incident light stored in the address decoder 19 and the control data stored in the data decoder section 21 are input as a command voltage to the transmitted light amount control section 9 corresponding to the corresponding pixel by the distribution gate 23. Therefore, when a voltage is applied to the electrode 8a of the transmission 118 from the transmitted light amount control unit 9, the alignment state of the optical object '1i8c of the transmission film base material 8b changes in proportion to the command voltage, so that the incident light 8d The transmittance changes, and it becomes possible to control so that all the photodiodes 4 receive an appropriate amount of incident light.

In this way, the pixel-by-pixel dimming type image sensor of this embodiment differs from the conventional CC[) image sensor in that the transmission 118
Since it is possible to control the amount of incident light to the pixel section,
Even for images with large differences in light intensity distribution from metallic glossy workpieces that are close to specular reflection, the entire screen can be identified by simply using υJ111 data obtained by an external image processing unit to detect changes in light intensity distribution. It is possible to obtain a high-quality image capture screen.

It should be noted that the present invention is not limited to the area-type image sensor as in the embodiments described above, but can also be applied to a linear-type image sensor in the same manner as described above.

U Effects of the invention j As described above, according to the present invention, a command voltage determined from an image storage signal is applied from the transmitting section to the transmitting film disposed on the light-receiving surface of the photosensitive section. The transmission film for incident light can be controlled for each pixel according to the magnitude of the command voltage, so the entire screen can be controlled at a signal level suitable for image identification.
Moreover, it is possible to provide a pixel part dimming value imaging element that can obtain a flij image screen without damaging the original image.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram showing the overall structure of the pixel-by-pixel dimming type @image element according to the present invention, Fig. 2 is a basic structural diagram showing the light-receiving pixel portion in the same embodiment, and Figs. 3 and 4 are transparent diagrams. FIG. 3 is an explanatory diagram of the structure and operation of a membrane. 1... Package, 2... Light receiving pixel,
2a... Light receiving surface, 3... Insulating film, 4.
... Photodiode, 5 ... Storage electrode, 6 ... Signal charge, 7 ... Shift electrode, 8 ... Transmission film, 8a.・・・・Denkobu, 8
b...Transmission film base material, 8C...Optical substance, 9...Transmitted light amount control unit, 10...C
CD analog shift register, 11... Vertical register clock terminal, 12... Horizontal register clock terminal, 13... Output gate, 1
4...Operating signal terminal, 15...Floating capacitor, 16...MOS) - transistor section, 17...Output signal terminal, 18...
...Output drain voltage terminal. Applicant's agent Patent attorney Takeshi Suzue Industry Figure 1 Figure 2

Claims (1)

[Claims] A photosensitive part that photoelectrically converts incident light for each pixel and accumulates it as a signal charge, and a photosensitive part arranged for each pixel on the light receiving surface of this photosensitive part, so that the amount of transmitted light can be controlled according to the magnitude of the applied voltage. a transmission film, a transfer section that scans and transfers the signal charges accumulated in the photosensitive section for each pixel, a floating diffusion layer section into which the signal charges transferred by the transfer section are injected, and the floating diffusion layer section. a conversion section that converts the signal charge injected into a voltage and outputs it as an imaging signal to an external image processing section; A pixel-by-pixel light control type image pickup device, comprising: a transmission amount control section that controls the amount of transmission of incident light to the transmission film for each pixel.