JPH09298626A - Flexible printed wiring board for image sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the mixing-in of various noise to the photoelectric conversion analog signals of an image sensor without damaging the flexibility of a flexible printed wiring board. SOLUTION: This flexible printed wiring board 50 is turned to a double-sided printed wiring board and a part where the image sensor 1 is disposed is turned to a solid ground part 53. A mesh-like ground pattern 54 is formed on one surface side (A surface side) of a wiring part between the solid ground part 53 and the part where a male type connector 51 is formed and an analog signal pattern part and a digital signal pattern part are spatially separately formed on the surface (defined as a B surface) on the opposite side of the side where the mesh-like ground pattern 54 is formed. Thus, a connection structure between the image sensor 1 and the signal processing substrate of the photoelectric conversion analog signals is turned to the structure with less mixing-in of the noise to the photoelectric conversion analog signals.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is applied to an image reading device or the like having an image sensor such as a CCD, and more specifically, an image sensor and a signal processing board arranged in the image reading device or the like. The present invention relates to a flexible printed wiring board for an image sensor, which is suitable for application to a wiring structure between them.

[0002]

2. Description of the Related Art An image reading apparatus, for example, illuminates a document placed on a document table with illumination light to condense the light containing image information carried on the document as reflected light or transmitted light. After being guided to the optical system, it is photoelectrically read by a linear image sensor such as a CCD. In this case, the two-dimensional image information can be obtained by reading the original in the main scanning direction by the linear image sensor and by relatively conveying the original in the sub-scanning direction substantially orthogonal to the main scanning direction. .

This image information is a photoelectric conversion analog signal, which is output from the image sensor. Usually, this photoelectric conversion analog signal is converted into a digital image signal in order to facilitate image signal processing such as contour enhancement processing, gradation conversion processing, and binarization processing. Therefore, the photoelectric conversion analog signal is supplied to the A / D converter.

The arrangement structure of such an image reading apparatus will be described. Particularly, in an image reading apparatus which requires high image quality, an image sensor having an IC package structure is
Since the accuracy of the optical placement position is important, it is fixed on the optical surface plate, while the A / D converter, which is not so limited in terms of placement position optically, is used together with other electronic components such as a glass epoxy substrate. Placed on the printed wiring board.

Therefore, it is necessary to electrically connect the image sensor and the printed wiring board for processing the photoelectric conversion analog signal.
For example, a connector with leads has been used.

[0006]

The image sensor is driven by various timing signals such as a transfer clock, a shift pulse, and a reset pulse, and there are amplitudes of about 12 V. These timing signals (binary signal) are used. Therefore, it can be considered as a digital signal.) Is easily mixed as noise into the photoelectric conversion analog signal carrying the image information.

The level of this mixed noise is the target S
In the case of an image reading device having a value smaller than the / N value, its mixing does not pose a problem, but in order to obtain a photoelectric conversion analog signal for reproducing a particularly high-definition image, the above-mentioned read It was found to be a problem with the attached connector. This is because the noise amount radiated from the lead transmitting the digital signal with respect to the lead transmitting the photoelectric conversion analog signal exceeds the target S / N value.

The present invention has been made in consideration of the above problems, and a connection structure between an image sensor and a printed wiring board for processing the photoelectric conversion analog signal is converted into a photoelectric conversion analog signal. It is an object of the present invention to provide a flexible printed wiring board for an image sensor, which enables a structure in which the noise is less mixed.

Further, according to the present invention, the connection structure between the image sensor and the printed wiring board for processing the photoelectric conversion analog signal has a structure in which noise is hardly mixed into the photoelectric conversion analog signal, and is easy to handle. An object is to provide an easy flexible printed wiring board for an image sensor.

[0010]

The present invention has, for example, a flexible printed wiring board, an image sensor is arranged at one end of the flexible printed wiring board, and a conductor of the board is provided at the other end. It is characterized in that a male connector utilizing the is formed.

According to the present invention, the printed wiring board for processing the photoelectric conversion analog signal output from the image sensor and the image sensor can be connected with a flexible and simple structure. As a result, the stress applied to the image sensor can be reduced.

In this case, the flexible printed wiring board is a double-sided printed wiring board, the portion where the image sensor is disposed is a solid ground portion, and the wiring portion between the solid ground portion and the portion where the male connector is formed is A mesh-shaped ground pattern is formed on one surface side (A surface side), and an analog signal pattern, a digital signal pattern, a DC power supply pattern, and a surface on the opposite side (the surface B) on which the mesh-shaped ground pattern is formed. By forming the ground pattern, the connection structure between the image sensor and the printed wiring board for processing the photoelectric conversion analog signal can be a structure in which noise is less mixed into the photoelectric conversion analog signal.

Further, the pattern formed on the B side is
The digital signal pattern and the analog signal pattern (including the DC power supply pattern) are divided on both sides in the width direction orthogonal to the wiring direction, and the digital signal pattern, the analog signal pattern, and the By forming the ground patterns on both sides of the DC power supply pattern, it is possible to obtain a structure in which noise is not mixed into the photoelectric conversion analog signal as much as possible.

Further, by forming a slit between the analog signal pattern side and the digital signal pattern to a position separated from the male connector by at least 3 cm or more from the end of the solid ground portion, more flexibility can be obtained. The male connector can be easily inserted into and removed from the printed wiring board for signal processing by grasping at least a portion within 3 cm of the end portion of the male connector in which the slit is not formed. can do.

Furthermore, the present invention has a flexible double-sided printed wiring board, an image sensor is arranged at one end of the flexible double-sided printed wiring board, and the conductor of the board is used at the other end. A surface on which a male connector is formed and on which the image sensor is arranged (A
Face. The portion other than the input / output terminal portion of the image sensor is a solid ground portion, and a mesh-shaped ground is formed on one surface side (A surface side) of the wiring portion between the solid ground portion and the portion where the male connector is formed. Pattern is formed,
A photoelectric conversion analog signal pattern, a digital signal pattern, a DC power supply pattern, and a ground pattern are formed on the opposite surface (the surface B) on which the mesh-like ground pattern is formed, and the back surface side (B
A surface side) and a buffer side to which a photoelectric conversion analog signal, which is an output signal of the image sensor, is provided on the back side of the solid ground portion, and the output side of the buffer amplifier is connected to the photoelectric conversion analog signal pattern. Is characterized by.

According to the present invention, the pattern wiring section between the output terminal of the photoelectric conversion analog signal of the image sensor and the buffer amplifier is the shortest, and the pattern wiring section is shielded from the image sensor main body by the solid ground. Structure. For this reason, it is possible to block the mixing of EMI (electromagnetic interference) noise radiated from the image sensor body. Since the output impedance of the output terminal of the photoelectric conversion analog signal of the image sensor is usually a relatively high value of about several hundred Ω to 2 kΩ,
Shortening the pattern wiring section having a high output impedance is extremely effective in preventing the mixing of noise.

In this case, a resistor is inserted between the output side of the buffer amplifier and the photoelectric conversion analog signal pattern on the flexible printed wiring board to form between the photoelectric conversion analog signal pattern and the mesh-shaped ground pattern. By forming a low-pass filter by utilizing the distributed capacitance, it is possible to block high-frequency noise components higher than the photoelectric conversion analog signal component by this low-pass filter.

The above invention is effective as an image sensor, particularly when applied to a CCD image sensor.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows a schematic configuration of an image reading apparatus 10 to which this embodiment is applied. In the image reading apparatus 10, the document cassette 12 transported by the transport mechanism 11 in the arrow Y direction (sub-scanning direction) is illuminated by the illumination light from the illumination optical system (illumination light source) 14 in the arrow X direction (also referred to as the main scanning direction X). .) And the document cassette 1 is illuminated.
The image information recorded on the transmissive document F held in 2 is
Light (which may be transmitted light or reflected light, but in this embodiment, transmitted light) L is condensed on an image forming section 18 by an image forming optical system 16 including a plurality of condenser lenses, and an electric signal is formed by the image forming section 18. Is configured to be converted to. The image forming optical system 16 and the image forming unit 18 are fixed to an optical surface plate (not shown).

The illumination light source 14 has a cylindrical diffusion cavity 22 in which a light diffusion surface is formed on the inner peripheral surface and a slit 20 is formed along the longitudinal direction, and the diffusion cavity 22.
Light source 2 consisting of halogen lamps attached to both ends of
4a and 24b.

The image forming unit 18 is mounted on the lower surface of the base 28 on which the slit 31 is formed, and has prisms 32a to 32c for decomposing the transmitted light L into R, G, and B lights. Line-shaped CCD linear image sensor sensors (simply referred to as image sensors) 1a to 1c as photoelectric conversion elements are fixed to the prisms 32a to 32c with a transparent adhesive.

As shown in FIG. 2, this image sensor 1
The configuration of a to 1c is basically a configuration of a dual in-line type IC package, and photoelectric conversion pixels (simply,
Also called a pixel. ) P is a light receiving portion 2 in which P is linearly connected in the longitudinal direction, and a transfer portion 3 including an odd pixel transfer portion 3o and an even pixel transfer portion 3e formed on both sides along the light receiving portion 2.
It is composed of

In practice, the transfer section 3 is covered with a metal film such as an aluminum vapor deposition film (not shown) so as to block the transmitted light L.

The light L received by the light receiving section 2 is photoelectrically converted by each pixel P, and is shifted to the odd / even pixel transfer sections 3o, 3e corresponding to the odd / even pixel Po, Pe for each shift pulse generated at a constant time. Then, the FDA (Floating Diffusion)
Image sensors 1a to 1c through amplifiers 4o and 4e
Is output as an odd pixel signal So and an even pixel signal Se which are photoelectric conversion analog signals.

The odd pixel signal So and the even pixel signal Se output from the image sensors 1a to 1c are
As shown in FIG. 1, the input amplifier (in the image processing board) 34 in the signal processing board (image processing board) 34 is mounted through the female connectors 52a to 52c mounted on the signal processing board 34 through the flexible printed wiring boards 50a to 50c which also function as connectors. Will be described later).

In the following description of the wiring structure and the like, the same applies to the image sensors 1a to 1c, and therefore the symbols a to c are used unless otherwise required.
Will be omitted and simply referred to as the image sensor 1. The flexible printed wiring boards 50a to 50c are also referred to as the flexible printed wiring board 50. Similarly, other components will be described by omitting the reference signs a to c, o, and e.

FIG. 3 schematically shows a connection structure including a flexible printed wiring board 50 on which electronic parts are mounted.

The surface of the image sensor 1 including the light receiving portion 2 is adhered and fixed to the emission surface of the transmitted light L of the prism 32 by a transparent adhesive. Each input / output terminal of the image sensor 1 is electrically connected to one end of the flexible printed wiring board 50 via the IC socket 41. The flexible printed wiring board 50 has a base film made of a polyimide material, and various patterns, which will be described in detail later, are formed on both sides of the base film by conductors (rolled copper foil). Both outer surfaces of the conductor are covered with a cover lay (not shown) which is an insulating film made of polyimide except for a portion where the land is formed. IC socket 4
A reinforcing plate 42 made of a glass epoxy material is attached between 1 and the flexible printed wiring board 50 itself.

At the other end of the flexible printed wiring board 50, a male connector 51 is formed by the conductor of the board 50. The male collector 51 is inserted into and removed from the female connector 52 attached to the signal processing board 34. A resin reinforcing plate is attached to one surface of the male connector 51.

FIG. 4 is a pattern diagram of the A-side pattern 50A of the flexible printed wiring board 50, and FIG.
Shows a pattern diagram of a B-side pattern 50B seen through from the A-side pattern 50A side. As will be described in detail later, FIG. 6 mainly shows a B-side pattern 5 which is a signal pattern.
The schematic circuit signal pattern wiring diagram of the image signal acquisition system including 0B is shown.

As shown in FIG. 4, in the A-side pattern 50A, the surface on which the image sensor 1 is arranged (opposing surface of the image sensor 1) is a full conductor and is at the ground potential. It is set to 53. In the wiring portion between the solid ground portion 53 and the male connector 51, a mesh-shaped ground pattern 54 having a side of about 2.5 mm (the area of one mesh is 2.5 × 2.5 mm ² ) is formed. It is formed on the entire surface.

The photoelectric conversion analog signal Sa output through the FDA 4 (see FIG. 2) of the image sensor 1 is supplied to the back surface side (the B surface pattern 50B side shown in FIG. 5) corresponding to the solid ground portion 53. A pattern in which a buffer amplifier 61 (see FIG. 6) such as an emitter follower is surface-mounted is formed. In this case, the buffer amplifier 61 is
In the case of an emitter follower, which has an impedance conversion function, the FDA 4 of the image sensor 1 has a relatively high output impedance (in this embodiment, several hundred Ω to 2 kΩ).
Can be converted into a low impedance of about several Ω or less.

In this case, as shown in FIG. 7, since the input portion of the buffer amplifier 61 formed by the chip transistor is arranged below the solid ground portion 53, the influence of the EMI emitted from the image sensor 1 is blocked. can do. Therefore, the photoelectric conversion analog signal Sa output from the buffer amplifier 61 does not include noise due to this electromagnetic radiation, and the S / N value increases accordingly. In FIG. 7, reference numeral 71 is a base film made of polyimide, and reference numeral 72 is a pattern for surface mounting parts formed on the opposite side of the solid ground portion 53.

The mesh-shaped ground pattern 5 shown in FIG.
4 is formed on the opposite side, that is, on the B-side pattern 50B shown in FIG. 5, the width direction Q orthogonal to the wiring direction Qa.
Digital signal pattern part (group) 55D and analog signal pattern part (group) on both sides of b {DC power supply pattern part (group)
And 55A are provided separately.

By physically and spatially separating the digital signal pattern portion 55D and the analog signal pattern portion 55A, for example, the low level is 0V and the high level is +12.
Noise mixed in the analog signal pattern portion 55A from the digital signal pattern portion 55D through which a digital signal such as a transfer clock formed of a square wave signal such as V passes is reduced.

As shown in FIG. 6, each analog signal pattern (including the DC power supply pattern) forming the analog signal pattern portion 55A has a so-called sandwich pattern arrangement structure sandwiched by the ground patterns GND. .

For example, both sides of an analog signal pattern such as the pattern of the photoelectric conversion analog signal Sa and the pattern of the DC power supply + 12V (in practice, the DC power supply uses + 10V and + 5V in addition to this + 12V). The ground pattern GND is arranged.

In the image sensor 1, the inventors of the present application have found that about half the value of the noise component (including the power supply high frequency ripple component) on the DC power supply pattern + 12V is mixed in the FDA 4. ,
In this way, the DC power source + 12V pattern and the like are also sandwiched from both sides by the ground pattern GND, and as a result, the mixing of noise into the photoelectric conversion analog signal Sa is minimized. In this case, noise generated by the DC power supply + 12V pattern or the like is caused by the ground patterns GN on both sides of the noise.
It will be absorbed by D.

Similarly, the digital signal pattern portion 55D also has a so-called sandwich structure in which each digital signal pattern such as the reset pulse Rp, the shift pulse Sp, and the transfer clock φ is sandwiched by the ground pattern GND. By adopting a sandwich-like structure, it is possible to prevent the diffusion of noise due to these digital signals to a distant place.

As shown in FIGS. 3 to 5, a slit 63 is formed from the end on the solid ground portion 53 side along the inside of the analog signal pattern portion 55A, and the end on the other side of this slit 63 is formed. The male connector 51 is formed at least a predetermined length Dmin away from the end of the male connector 51 by Dmin = 3 cm or more. Further, the slit 64 having substantially the same length is formed substantially parallel to the slit 63. Slit 6 like this
By forming 3, 64, the flexibility of the flexible printed wiring board 50 is further enhanced, and the signal processing board 3
Even when the male connector 51 of the flexible printed wiring board 50 is connected to the female connector 52 on the fourth side, the stress applied to the image sensor 1 via the flexible printed wiring board 50 can be minimized. The image sensor 1 does not come off from the prism 32. The flexibility of the flexible printed wiring board 50 is further ensured by using the mesh-shaped ground pattern 54 described above.

Moreover, since the slits 63 and 64 are formed at least a predetermined length Lmin away from the end of the male connector 51 by Lmin = 3 cm or more, as shown in FIG. 8, the thumb and the index finger of both hands are separated. , The slits 63, 6
It is possible to easily pull out and insert the male connector 51 to and from the female connector 52 on the image processing board 34 along the arrow direction by picking a flat surface portion having a length of 3 cm in which 4 is not formed.

In this embodiment, the flexible printed wiring board 50 has a total length of about 20 cm and a width W of about 4 cm (see FIG. 4). The reason why the substrate meanders on the side of the solid ground portion 53 is simply due to the requirement based on the restriction of the positional relationship between the signal processing board 34 and the optical system such as the prism 32. If there is no such restriction. Needless to say, it may be a linear flexible printed wiring board.

FIG. 9 shows the configuration of another embodiment of the present invention. In the example of FIG. 9, an emitter follower having a chip NPN transistor 81 as the buffer amplifier 61 is formed, and a chip resistor R2 for keeping the output impedance constant is inserted on the output side of the emitter. A low-pass filter is formed by the resistor R2 and the distributed capacitance C between the mesh ground pattern 54 on the flexible printed wiring board 50 and the transmission pattern of the photoelectric conversion analog signal Sa, and is constant from the photoelectric conversion analog signal Sa. Unnecessary high frequency noise components above the frequency can be removed. In this embodiment, the actual value of the distributed capacitance C is C≈200 pF,
Since the value of the resistor R2 is selected as R2 = 1kΩ,
The cutoff frequency is set to about 800 kHz.

In FIG. 9, the resistance value R1 is a bias resistance, and the input amplifier 83 arranged on the input side of the A / D converter 89 raises the input impedance on the receiving side and outputs the output impedance dance. It is for lowering. As is well known, the amplification degree of the input amplifier 83 including the operational amplifier 82 is determined by the resistors R4 and R5. The resistor R3 includes a male connector 51 and a female connector 5.
This is a pull-down resistor for holding the input voltage of the input amplifier 83 at 0 V when 2 is removed, and R3 = 100 kΩ is selected in this embodiment.

As described above, according to the above-described embodiment, first, as shown in FIG.
Since A and the digital signal pattern portion 55D are spatially separated, noise emission from the digital signal pattern portion 55D to the analog signal pattern portion 55A can be reduced. Further, a pattern of the photoelectric conversion analog signal Sa which is an analog signal pattern, a signal line such as a DC power supply + 12V pattern which is regarded as an analog signal pattern due to the peculiarity of the structure of the image sensor 1 and a digital signal pattern such as a transfer clock φ. As described above, since the signal lines are all sandwiched between the ground patterns GND, the electromagnetic radiation from each signal line is mainly absorbed by the adjacent ground pattern GND, and as a result, the photoelectric conversion analog signal Sa is transmitted. It is possible to prevent noise from being mixed into the generated pattern.

In addition, the flexible printed wiring board 50
In addition, since the entire back surface of the B-side pattern 50B, which is a signal pattern, is the mesh-shaped ground pattern 54, various radiation noises can be effectively shielded. As for the shield effect, the solid ground of the entire surface ground is more excellent, but when the solid ground is used, the flexibility of the flexible printed wiring board 50 is lowered, and the image sensor 1 and the female connector 5 on the signal processing board 34 are reduced.
The range of the mounting positions of 2 is restricted. However, by using the mesh-shaped ground pattern 54, the flexibility of the flexible printed wiring board 50 is increased, and the restrictions on the arrangement positions of various components can be relaxed. It should be noted that the actual mesh size may be determined optimally in accordance with the restrictions on the positions of these various components and the specifications such as the target S / N. The shape of the mesh ground pattern 54 can also be determined by simulation using a computer.

Further, according to this embodiment, the mounting surface of the image sensor 1 is the solid earth portion 53, and the buffer earth 61 for the photoelectric conversion analog signal Sa is provided on the rear surface side.
Since the solid earth portion 53 is provided, a so-called shield effect of blocking pulsed noise (mainly noise generated when various clocks rise and fall) emitted from the image sensor 1 is provided by the solid ground portion 53. can get. In this case, the length of the signal line from the output of the FDA 4 having a relatively high output impedance to the buffer amplifier 61, which is the output of the image sensor 1, becomes the shortest length as a result, and in this sense, noise is mixed. Can be reduced.

Furthermore, according to this embodiment, since the long slits (openings) 63 and 64 are provided in the longitudinal direction (wiring direction) of the flexible printed wiring board 50, the flexible printed wiring board 50 is bent. It is possible to reduce the generation of stress due to, and since the mesh-shaped ground pattern 54 is used, the flexible printed wiring board 50 itself becomes soft. As a result, the flexible printed wiring board 50 becomes difficult to break. In addition, on the male connector 51 side, a predetermined length L about a portion to be sandwiched by fingers is provided.
Since the slits 63 and 64 do not extend and are arranged in the min portion, it is extremely easy to insert and remove the flexible printed wiring board 50 into and from the mating female connector 52.

As shown in FIG. 9, the buffer amplifier 6
1 to the output side, depending on the specifications such as S / N, several hundred Ω to several k
By inserting Ω resistor R2, mainly distributed capacitance C
With, it becomes possible to form a low-pass filter, and unnecessary high-frequency components can be removed. In this case, since the filter uses the distributed capacitance C, its frequency response can be made smooth.

Further, the present invention is not limited to the above-described embodiments, and various configurations are possible without departing from the gist of the present invention, for example, an area image sensor can be used in place of the linear image sensor. Of course there are things that can be taken.

[0052]

As described above, according to the present invention, a flexible printed wiring board devised in various ways is used as the connection structure between the image sensor and the printed wiring board for processing the photoelectric conversion analog signal. As a result, less noise is mixed into the photoelectric conversion analog signal,
In addition, it is possible to construct a connection structure that is easy to handle.

The flexible printed wiring board according to the present invention is particularly suitable for application to an image reading apparatus using a so-called three-plate type image sensor which requires high image quality.

[Brief description of drawings]

FIG. 1 is a perspective view showing a schematic configuration of an image reading apparatus to which an embodiment of the present invention is applied.

FIG. 2 is a perspective view showing a configuration of an image sensor having an IC package structure.

FIG. 3 is a diagram schematically showing a configuration of an embodiment of the present invention.

FIG. 4 is a plan view for explaining a mesh-shaped ground pattern surface.

FIG. 5 is a plan view for explaining a signal pattern surface.

FIG. 6 is a wiring diagram provided for explaining how to divide signal lines.

FIG. 7 is a partial cross-sectional side view provided for explaining interference between the image sensor and the buffer amplifier.

FIG. 8 is a diagram used for explaining an action of inserting and removing the flexible printed wiring board into and from the connector.

FIG. 9 is a diagram provided for explaining a configuration of a low-pass filter that uses distributed capacitance.

[Explanation of symbols]

1a-1c ... Linear image sensor 2 ... Light receiving part 4o, 4e ... FDA 18 ... Imaging part 32a-32c ... Prism 34 ... Signal processing board 50a-50c ... Flexible printed wiring board 51 ... Male connector 52 ... Female connector 54 ... Ground pattern 55A ... Analog signal pattern section 55D ... Digital signal pattern section 61 ... Buffer amplifier 63, 64 ... Slit

Claims (10)

[Claims] 1. A flexible printed wiring board, wherein an image sensor is arranged at one end of the flexible printed wiring board, and a male connector using the conductor of the board is formed at the other end. A flexible printed wiring board for an image sensor, which is characterized in that 2. A flexible double-sided printed wiring board, wherein an image sensor is arranged at one end of the flexible double-sided printed wiring board, and a male connector using the conductor of the board is formed at the other end. A portion other than the input / output terminal portion of the image sensor on the surface on which the image sensor is arranged (referred to as surface A) is a solid ground portion, and the solid ground portion and a portion where the male connector is formed. A mesh-shaped ground pattern is formed on one surface side (A surface side) of the wiring portion between them, and an analog signal pattern and a digital signal are formed on the opposite surface (referred to as B surface) on which the mesh-shaped ground pattern is formed. A flexible printed wiring board for an image sensor, wherein a pattern, a DC power supply pattern and a ground pattern are formed. 3. At least one slit is formed along the wiring direction from an end of the solid ground portion to a section separated from the male connector by at least 3 cm or more. 2. A flexible printed wiring board for an image sensor as described in 2. 4. The pattern formed on the surface B is divided into the digital signal pattern and the analog signal pattern (including the DC power supply pattern) on both sides in the width direction orthogonal to the wiring direction, and The flexible printed wiring board for an image sensor according to claim 2, wherein ground patterns are formed on both sides of the digital signal pattern, the analog signal pattern, and the DC power supply pattern for each one. 5. At least one slit is formed along the wiring direction from an end of the solid ground portion to a section separated from the male connector by at least 3 cm, and the slit is formed in the digital signal pattern. The flexible printed wiring board for an image sensor according to claim 4, wherein the flexible printed wiring board is formed between the analog signal pattern and the analog signal pattern (including the DC power supply pattern). 6. A flexible double-sided printed wiring board, wherein an image sensor is arranged at one end of the flexible double-sided printed wiring board, and a male connector using the conductor of the board is formed at the other end. A portion other than the input / output terminal portion of the image sensor on the surface on which the image sensor is arranged (referred to as surface A) is a solid ground portion, and the solid ground portion and a portion where the male connector is formed. A mesh-shaped ground pattern is formed on one surface side (A surface side) of the wiring portion between the photoelectric conversion analog signal patterns on the opposite surface (referred to as B surface) on which the mesh-shaped ground pattern is formed, A digital signal pattern, a DC power supply pattern, and a ground pattern are formed, and on the back side (B side) of the image sensor, the back side of the solid ground portion. In the Bafaanpu photoelectric converting analog signal which is an output signal of the image sensor is supplied provided, the flexible printed circuit board for an image sensor, wherein the output side of the Bafaanpu is connected to the photoelectric converting analog signal pattern. 7. The pattern formed on the B surface is divided into the digital signal pattern and the analog signal pattern (including the DC power supply pattern) on both sides in the width direction orthogonal to the wiring direction, and 7. The flexible printed wiring board for an image sensor according to claim 6, wherein ground patterns are formed on both sides of the digital signal pattern, the analog signal pattern, and the DC power supply pattern for each one. 8. At least one slit is formed along the wiring direction from an end of the solid ground portion to a section separated from the male connector by at least 3 cm, and the slit is the digital signal pattern. The flexible printed wiring board for an image sensor according to claim 7, wherein the flexible printed wiring board is formed between the analog signal pattern and the analog signal pattern (including the DC power supply pattern). 9. A distributed capacitor formed between the photoelectric conversion analog signal pattern and the mesh ground pattern is inserted by inserting a resistor between the output side of the buffer amplifier and the photoelectric conversion analog signal pattern. 9. The flexible printed wiring board for an image sensor according to claim 6, wherein a low pass filter is formed by utilizing the low pass filter. 10. The flexible printed wiring board for an image sensor according to claim 1, wherein the image sensor is a CCD linear image sensor.