JPH11337815A - Solid photographing device and range finder for camera - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make the range findable more widely from a short distance to a long distance by arranging two kinds of pixel lines of a usual pixel line and a pixel line applied with a filter of transmissivity higher in an infrared region than a visible light region. SOLUTION: A pixel line 1 for a passive system having a reference part and a standard part and a pixel line 2 for an active system coated with a filter that the transmissivity becomes higher in an infrared region than a visible light region are arranged in parallel with two lines and a shift electrode 3 and a CCD register 4 are provided respectively on the outside. An output circuit 5 covering a transferred signal charge to an output signal is connected to the output terminal of the CCD register 4 transferring the signal charge photoelectric-converted by the pixel line 1 for the passive system. An amplifier circuit 6 and an output circuit 7 converting its signal charge into the output signal are connected to the output terminal of the CCD register 4 transferring the signal charge photoelectric-converted by the pixel line 2 for the active system. Then, the output signals from these output circuits 5, 7 are synthesized by a synthetic circuit 8.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solid-state imaging device, and more particularly to a solid-state imaging device used for an image sensor for auto-focusing (hereinafter, referred to as AF) of a camera.

[0002]

2. Description of the Related Art There are two types of AF: an active method used in a lens shutter camera having a zoom of about 2 to 4 times, in which an object is irradiated with infrared light and a reflected light is used to measure a distance, and an infrared light. Because the subject is too far away to receive the reflected light,
For example, there is a passive method used for a single-lens reflex camera that receives light (external light) of an image from a subject and measures the distance.

A conventional AF solid-state imaging device will be described with reference to the drawings. FIG. 6 is a schematic diagram showing a conventional passive distance measuring method. As shown in FIG. 6, in the passive method, two object light beams, a reference portion light beam and a reference portion light beam, enter two portions of the photographing lens 102, respectively.
Light receiving element 1 in which a plurality of photoelectric conversion elements are arranged in a row via a condenser lens 103 and a separator lens 104
An image is formed on the reference unit 106 and the reference unit 107 in FIG.
By moving the position of the photographing lens 102 back and forth, the image interval between the two formed subject images becomes a predetermined value, and a focusing state is established.

[0004] On the other hand, in the active system, as shown in FIG.
09 and reaches the subject 101, and the reflected light is projected on the light receiving element 105 via the light receiving lens 110. Distance measurement is performed based on which position of the light receiving element 105 has an image of the infrared LED 108.

[0005]

As shown in FIG. 8, the spectral sensitivity characteristic of the conventional solid-state imaging device for AF has a wavelength of 5 mm.
The spectral sensitivity is high in the visible light range from 00 nm to 600 nm.
For this reason, in the passive method using external light, FIG.
As shown in (a), the characteristics are similar to those in FIG.

Further, the spectral sensitivity of infrared light having a wavelength of 800 nm to 900 nm which is reflected back from the subject 101 is as follows:
It is about 20 to 50% of the visible light region. For this reason, if the external light is strong when the active method is used, there is a problem that it is difficult to distinguish between the external light component and the infrared light component as shown in FIG. Was.

When the passive method is used at a short distance because infrared light cannot be detected, the reference unit 106 and the reference unit 10
There is a problem that it is difficult to adjust the image interval of the image No. 7 and the focusing becomes difficult.

In view of the above circumstances, the present invention can measure the distance using the active method even if the influence of external light is strong, and can accurately measure the distance even at a short distance or a long distance. It is an object of the present invention to provide a solid-state imaging device for AF that can be performed.

[0009]

In order to achieve the above object, a solid-state imaging device according to the present invention comprises: a first pixel column in which a plurality of photoelectric conversion units corresponding to respective pixels are arranged in a line;
A first CCD register for sequentially transferring signal charges photoelectrically converted by the photoelectric conversion units of the pixel columns in a predetermined direction;
A first output circuit for outputting a first analog signal corresponding to the signal charge output from the first CCD register;
A second pixel row in which a plurality of photoelectric conversion units corresponding to each pixel are arranged in a row and a filter having a higher light transmittance at a wavelength in an infrared light region than a wavelength in a visible light region is applied; A second CCD register for sequentially transferring the signal charges photoelectrically converted by the photoelectric conversion units of the pixel row in a predetermined direction, and a second analog signal corresponding to the signal charges output from the second CCD register And a combining circuit that outputs a combined signal of the first analog signal and the second analog signal.

Further, it is preferable that the apparatus further comprises an amplifier circuit for amplifying the second analog signal output from the second output circuit and outputting the amplified second analog signal to the synthesis circuit. Further, a first pixel row in which a plurality of photoelectric conversion units corresponding to each pixel are arranged in a row, and signal charges photoelectrically converted by the photoelectric conversion units in the first pixel row in a predetermined direction. A first CCD register for transferring, a first output circuit for outputting a first analog signal corresponding to the signal charge output from the first CCD register, and a plurality of photoelectric conversion units corresponding to each pixel; A second pixel row, which is arranged in a row and is coated with a filter having a higher light transmittance at a wavelength in the infrared light region than a wavelength in the visible light region, and photoelectric conversion in each of the photoelectric conversion units in the second pixel row Second CC that sequentially transfers the transferred signal charges in a predetermined direction.
D register, and a second register for outputting a second analog signal corresponding to the signal charge output from the second CCD register.
And a selector for switching and outputting the first analog signal and the second analog signal.

Further, it is preferable that the first pixel column has a reference portion and a reference portion. A first pixel row in which a light-emitting element that emits infrared light toward a subject, and a photoelectric conversion unit that converts light incident through a photographing lens into an electric signal are arranged in a row; And a first output circuit for outputting a first analog signal corresponding to the signal charge output from the first CCD register. A filter in which a filter having a high light transmittance in the wavelength region of infrared light than the wavelength region of visible light is applied and a photoelectric conversion unit that converts infrared light reflected from the subject into an electric signal is arranged in a line. And a second C that sequentially transfers the signal charges photoelectrically converted by the second pixel column in a predetermined direction.
A CD register, a second output circuit for outputting a second analog signal corresponding to the signal charge output from the second CCD register, the first analog signal and the second
A solid-state imaging device including a synthesizing circuit that outputs a synthesized signal with an analog signal of the same; a distance measuring circuit that measures a distance to the subject based on an output result of the solid-state imaging device; 2. Description of the Related Art There is a distance measuring device for a camera, comprising a calculation circuit for controlling a focus driving system.

[0012]

BRIEF DESCRIPTION OF THE DRAWINGS FIG.
A solid-state imaging device according to the first embodiment will be described. FIG. 1 is a configuration diagram of the solid-state imaging device according to the first embodiment of the present invention.

As shown in FIG. 1, a solid-state imaging device according to a first embodiment of the present invention includes a passive-type pixel row 1 having a reference section and a reference section, and an infrared-ray pixel array 1 that is more infrared than the visible light region. A filter having a high transmittance in the light region, for example, an active type pixel column 2 coated with a black filter is arranged in two rows in parallel.
A register 4 is provided. Pixel column 1 for passive system
CCD register 4 for transferring the signal charge photoelectrically converted by
Is connected to an output circuit 5 for converting the transferred signal charges into an output signal. Further, the CC for transferring the signal charge photoelectrically converted by the active type pixel column 2 is used.
The output terminal of the D register 3 is connected to an amplifier circuit 6 for amplifying the transferred signal charge and an output circuit 7 for converting the amplified signal charge to an output signal. The output signals output from the two output circuits 5 and 7 are combined by the combining circuit 8 to output a combined signal.

A black filter generally used to suppress reflection by covering over Al of a CCD area sensor is shown in FIG.
As shown in the spectral sensitivity characteristics of
Although hardly transmits light in the visible light region of 00 nm,
It is known that it has a property of transmitting light in an infrared light region having a wavelength of 800 nm or more and increasing sensitivity. Therefore, by applying the black filter to the pixel rows, it becomes easy to receive the infrared light component by cutting the visible light even if the external light is strong, and accurate distance measurement becomes possible.

The signal charge of the infrared light component transferred from the active type pixel column 2 shown in FIG. 3A is amplified, for example, about 2 to 5 times, and then the passive type pixel shown in FIG. By combining with the signal charge of the external light component photoelectrically converted in column 1, the infrared light component can be emphasized as shown in FIG. Therefore, even if the external light is strong, the distance can be measured using the active method. Also, even in a long distance where infrared light does not reach, a passive signal is output as it is, so that both the active method and the passive method can be used, and it is possible to support ranging from a short distance to a long distance. .

The amplifying circuit 6 for amplifying the infrared light component includes:
It can also be realized by connecting an arbitrary number of circuits similar to the output circuits 5 and 7 in series. Next, a solid-state imaging device according to a second embodiment of the present invention will be described with reference to FIG. FIG. 4 is a configuration diagram of a solid-state imaging device according to a second embodiment of the present invention.

As shown in FIG. 4, the solid-state imaging device according to the second embodiment of the present invention has a passive-type pixel column 1 having a reference portion and a reference portion, similarly to the first embodiment.
And a filter having a transmittance higher in the infrared region than in the visible region, for example, two active pixel columns 2 coated with a black filter are arranged in parallel, and the corresponding shift electrode 3 and CCD register 4 are provided. Each C
The output terminals of the CD register 4 are connected to output circuits 5 and 7 for converting the transferred signal charges into output signals.
Each output signal output from the output circuits 5 and 7 is connected to a switch 9, and the output signal selected by the switch 9 is output. The switch 9 detects an active output signal, and is controlled so as to select a passive output signal when the output signal is smaller than a predetermined value. Note that the present invention is not limited to this embodiment, and an active type output signal may be amplified and then connected to a switch.

Next, a camera distance measuring apparatus according to a third embodiment of the present invention will be described with reference to FIG. FIG. 5 is a schematic view of a camera distance measuring apparatus according to a third embodiment of the present invention.

As shown in FIG. 5, the camera distance measuring apparatus according to the third embodiment has a light emitting element 10 such as an LED.
A light receiving element 12 such as a photoelectric conversion element for receiving light through a photographing lens 11, a distance measuring circuit 13 for measuring a distance from an incident light to a subject, a CPU 14 as an arithmetic circuit, an AF
It comprises a drive system 15.

By using the solid-state imaging device of the present invention for the light receiving element 12, distance measurement from a short distance to a long distance can be performed. Therefore, the distance measurement device of the present embodiment can be used for a wide range of zooming from low magnification to high magnification. It can be used in cameras.

In addition, even when external light is strong at a short distance, accurate distance measurement can be performed by independently extracting and amplifying the infrared light component. Note that the present invention is not limited to the first to third embodiments, and the same effect can be obtained even when all of the red, green and blue filters are applied in place of the black filter.

Further, an active-type pixel column may be arranged between the reference portion and the reference portion of the passive-type pixel column to make the pixel column one line. By increasing the distance (base line length) between the reference section and the reference section, the angle of view is widened, and ranging over a wider range becomes possible.

[0023]

According to the present invention, two types of pixel rows, that is, a conventional pixel row and a pixel row coated with a filter having a higher transmittance in the infrared light region than in the visible light region, are arranged to provide an active system. And the passive method can be used together, and it is possible to measure a wider range from a short distance to a long distance. Further, by amplifying and outputting a signal obtained by photoelectrically converting the infrared light, it is possible to perform a short-distance accurate distance measurement with the infrared light even when the external light is strong.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a solid-state imaging device according to a first embodiment of the present invention.

FIG. 2 is a spectral sensitivity characteristic diagram of a black filter.

FIG. 3A is a diagram illustrating spectral sensitivity characteristics of an infrared light component signal transferred from an active mode pixel column. (B) Spectral sensitivity characteristic diagram of the external light component signal transferred from the passive pixel column. (C) Spectral sensitivity characteristics of the synthesized signal.

FIG. 4 is a configuration diagram of a solid-state imaging device according to a second embodiment of the present invention.

FIG. 5 is a schematic view of a camera distance measuring apparatus according to a third embodiment of the present invention.

FIG. 6 is a configuration diagram of a conventional passive AF sensor.

FIG. 7 is a configuration diagram of a conventional active type AF sensor.

FIG. 8 is a spectral sensitivity characteristic diagram of a conventional solid-state imaging device for AF.

FIG. 9A is a diagram illustrating spectral sensitivity characteristics of an external light signal component when a conventional passive method is used. (B) A spectral sensitivity characteristic diagram of an infrared light component when the conventional active method is used.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Pixel line for a passive system, 2 ... Pixel line for an active system, 3 ... Shift electrode, 4 ... CCD register, 5,7 ... Output circuit, 6 ... Amplification circuit, 8 ... Synthesis circuit, 9 ... Switch, 10 ... Light emission Element: 11, 102: photographing lens: 12, 105: light receiving element, 13: distance measuring device, 14: CPU, 15: AF drive system, 16: control interface, 101: subject, 103: condenser lens, 104: separator lens Reference numeral 106: Reference part 107: Reference part 108: Infrared LED 109: Projection lens 110: Light receiving lens

──────────────────────────────────────────────────続 き Continued on front page (51) Int.Cl. ⁶ Identification symbol FI // H04N 5/33 G03B 3/00 A

Claims (6)

[Claims] 1. A first pixel row in which a plurality of photoelectric conversion units corresponding to each pixel are arranged in a row, and a signal charge photoelectrically converted by each of the photoelectric conversion units in the first pixel row is converted into a predetermined signal. A first CCD register for sequentially transferring data in the
A first output circuit that outputs a first analog signal corresponding to the signal charge output from the CD register, and a plurality of photoelectric conversion units corresponding to each pixel are arranged in a line, and a plurality of photoelectric conversion units are arranged in an infrared region more than a visible light wavelength region. A second pixel row to which a filter having a high light transmittance in the wavelength region of light is applied; and a second pixel row for sequentially transferring signal charges photoelectrically converted by each of the photoelectric conversion units of the second pixel row in a predetermined direction. Two CCD registers and this second CCD
A second output circuit that outputs a second analog signal corresponding to the signal charge output from the register; and a combining circuit that outputs a combined signal of the first analog signal and the second analog signal. A solid-state imaging device characterized by the following. 2. The solid-state imaging device according to claim 1, further comprising an amplifier circuit for amplifying the second analog signal output from the second output circuit and outputting the amplified second analog signal to the synthesis circuit. 3. A first pixel row in which a plurality of photoelectric conversion units corresponding to each pixel are arranged in a line, and a signal charge photoelectrically converted by each of the photoelectric conversion units in the first pixel row is converted into a predetermined signal. A first CCD register for sequentially transferring data in the
A first output circuit that outputs a first analog signal corresponding to the signal charge output from the CD register, and a plurality of photoelectric conversion units corresponding to each pixel are arranged in a line, and a plurality of photoelectric conversion units are arranged in an infrared region more than a visible light wavelength region. A second pixel row to which a filter having a high light transmittance in the wavelength region of light is applied; and a second pixel row for sequentially transferring signal charges photoelectrically converted by each of the photoelectric conversion units of the second pixel row in a predetermined direction. Two CCD registers and this second CCD
A second output circuit that outputs a second analog signal corresponding to the signal charge output from the register; and a selector that switches and outputs the first analog signal and the second analog signal. A solid-state imaging device characterized by the above-mentioned. 4. The solid-state imaging device according to claim 1, wherein the first pixel row has a reference unit and a reference unit. 5. The solid-state imaging device according to claim 4, wherein said second pixel column is disposed between a reference portion and a reference portion of said first pixel column. 6. A first pixel column in which a light-emitting element that emits infrared light toward a subject, and a photoelectric conversion unit that converts light incident through a photographing lens into an electric signal are arranged in a single line.
A first CCD register for sequentially transferring signal charges photoelectrically converted by the pixel columns in a predetermined direction, and a first CCD register for outputting a first analog signal corresponding to the signal charges output from the first CCD register. An output circuit and a photoelectric conversion unit that applies a filter having a high light transmittance in an infrared light wavelength region than a visible light wavelength region and converts infrared light reflected from the subject into an electric signal are arranged in a line. A second pixel row,
A second CCD register for sequentially transferring the signal charges photoelectrically converted by the second pixel column in a predetermined direction; and a second CCD register corresponding to the signal charges output from the second CCD register.
A second output circuit for outputting an analog signal of
A solid-state imaging device including a synthesis circuit that outputs a synthesized signal of the analog signal and the second analog signal; a distance measurement circuit that measures a distance to the subject based on an output result of the solid-state imaging device; An arithmetic circuit for controlling an auto-focus driving system based on an output of the distance measuring circuit.