KR101050845B1 - Flexible Circuit Boards and Image Sensor Modules and Camera Modules Having the Same - Google Patents

Abstract

An object of the present invention is to provide a flexible circuit board having an electromagnetic shielding structure that shields an electric field and a magnetic field harmful to a human body, and thereby does not adversely affect image quality. A base layer having a circuit pattern formed on at least one of upper and lower surfaces of the film and the plastic film, and a base layer having an insulating layer covering the base layer; And an electromagnetic shielding film attached to at least one of an upper surface and a lower surface of the base layer without being electrically connected with a circuit pattern.

Description

 Flexible printed circuit board, image sense module and camera module comprising the same}

1 is a cross-sectional view showing a cross section of a conventional camera module,

2 is a cross-sectional view showing an image sensor module and a flexible circuit board provided therein according to the present invention;

3 is an enlarged cross-sectional view of part A of FIG. 2;

4 is a cross-sectional view of a camera module having the image sensor module of FIG. 2.

Explanation of symbols on the main parts of the drawings

100: camera module 101: image sensor module

110: circuit board 114, 161: adhesive

117: substrate-side electrode pad 120: image sensing element

125: imaging area 127: device side electrode pad

140: flexible circuit board 141: base layer

142: base layer 145: insulating layer

151: electromagnetic shielding film 201: optical system                 

210: lens housing 211: adhesive surface

215: device housing 240: lens

250: filter

The present invention relates to a flexible printed circuit board and a camera module having the same, and more particularly, to a flexible printed circuit board having an improved electromagnetic shielding structure, an image sensor module having the same, and the flexible printed circuit board, which is provided with a moving picture and photographs. And it relates to a camera module housed in a portable device that can transmit it.

Camera module is a device that can take videos and take pictures and transmit them, and is used in mobile devices such as mobile phones, mobile phones, notebook computers, PDAs, cameras for monitor insertion, car rear view cameras with bumpers, cameras for doors / interphones, etc. do.

1 is an exploded perspective view of a conventional camera module. As shown in FIG. 1, the conventional camera module 1 is made of an image sensor module 10 and an optical system 20. The image sensor module 10 includes a flexible printed circuit board (FPCB) 40 having a circuit pattern formed thereon, and an image of an external image passing through the optical system is captured and electrically connected to the flexible circuit board. The imaging element 12 is provided. A window portion is coupled to an upper portion of the imaging device 12 and exposes an imaging area 13 formed at the center of the imaging device 12. The optical system 20 includes a housing 21 and a lens holder 22.

One side of the flexible circuit board 40 is connected with the image pickup device 12 and the bonding means, by the adhesive agent 14, and the other side is connected to the main board of the main body of the portable device by forming a connector 48.

In this case, the flexible circuit board 40 usually includes a base layer 42 such as polyimide or polyester, and a wiring circuit 43 patterned on the surface of the base layer 42. And an insulator layer 44 formed on the wiring circuit 43.

By the way, the camera module 1 installed in a mobile device such as a mobile phone is in close proximity to the antenna. Therefore, since the flexible circuit board 40 is not far from the part where the antenna is attached, the input / output loss of the radio wave transmitted and received through the antenna is generated, and the electromagnetic wave is generated in the flexible circuit board 40, and the electromagnetic wave is flexible. Inflow into elements such as the image pickup device 12 electrically connected to the circuit board may cause noise, image quality, and color defects.

To prevent this, an electromagnetic shielding layer 50 such as an EMI shield layer may be attached to one or both surfaces of the flexible circuit board 40 by an adhesive or the like. The electromagnetic shielding layer 50 may shield the electric field and magnetic field harmful to the human body generated from the mobile phone.

However, since the electromagnetic shielding layer 50 is not reliably separated or in contact with elements such as the driving module ground portion of the camera module 1 and the image module ground portion, the antenna of noise generated in the driving circuit and the camera module is prevented. It plays a role and adversely affects the photographed image of the camera module 1, resulting in deterioration of image quality. In addition, the electromagnetic shielding layer 50 is an element that inhibits the ductility of the flexible circuit board 40.

The present invention has been made to solve various problems including the above problems, and includes a flexible circuit board having an electromagnetic shielding structure that shields electric and magnetic fields harmful to the human body and does not adversely affect image quality. An object of the present invention is to provide an image sensor module and a camera module having the image sensor module.

Still another object of the present invention is to achieve the above object and to have a flexible circuit board having excellent flexibility.

In order to achieve the above object, the flexible circuit board of the present invention:

A base layer having a plastic film and a circuit pattern formed on at least one of upper and lower surfaces of the plastic film, and a base layer having an insulating layer covering at least the circuit pattern; And

And an electromagnetic shielding film attached to at least one of upper and lower surfaces of the base layer without being electrically connected to the circuit pattern.

It is preferable to have an electromagnetic wave shielding film attached with at least one surface and an attack of the upper surface and the lower surface of the base layer.                     

In this case, an adhesive is disposed between the electromagnetic shielding film and the base layer, and the attack is preferably caused by the adhesive between the electromagnetic shielding film and the base layer.

Here, the electromagnetic shielding film is preferably made of the same material as the base layer.

On the other hand the image sensor module in another aspect of the present invention is:

Image sensing elements; And

A flexible circuit board having the above structure and having one side surface bonded by the image sensing element and bonding means is provided.

On the other hand, the camera module in another aspect of the present invention is:

An image sensor module having an image sensing element, and a flexible circuit board having the above structure and having a side surface bonded by the image sensing element and bonding means; And

It is coupled to the image sensor module, and has a lens housing mounted with at least one lens.

Hereinafter, with reference to the embodiments of the present invention shown in the accompanying drawings will be described in more detail.

2 shows an image sensor module 101 having a flexible circuit board according to a preferred embodiment of the present invention. Referring to FIG. 2, the image sensor module 101 according to an exemplary embodiment of the present invention includes a flexible circuit board 140 having a circuit pattern formed thereon, and an image of an external image is captured and electrically connected to the circuit board 110. The image sensing device 120 is connected.

The flexible circuit board 140 includes a base layer 141 and an electromagnetic shielding film 151. The base layer 141 includes a base layer 142 and an insulating layer 145. The base layer 142 is formed by forming a circuit pattern 144 on at least one surface of a plastic film 143 such as a polyamide film, and an upper surface and a lower surface of the plastic film 143. The insulating layer 145 is coated to cover at least the circuit pattern 144 and is usually made of the same material as the material of the plastic film 143.

The electromagnetic shielding film 151 is disposed on at least one surface of the upper and lower surfaces of the base layer 141. A circuit pattern is formed in the electromagnetic shielding film 151 so that the circuit pattern can capture electromagnetic waves or noise flowing from the outside. In this case, the electromagnetic shielding film 151 may be formed of the same material as the base layer 141 as shown in FIG. 2. However, the electromagnetic wave shielding film 151 is not limited to the same material as the base layer 141, and is included in the present invention as long as it can block electromagnetic waves, noise, and the like introduced into the base layer.

An adhesive may be formed between the plastic film 143 and the circuit pattern 144 and between the circuit pattern 144 and the insulating layer 145. In addition, when the flexible circuit board 140 is a double side-FPCB, the circuit patterns 144 disposed on both sides of the plastic film 143 are connected to each other through via holes, and the base layer 141 A finish plating layer may be formed at a portion exposed to the outside of the circuit pattern 144 to prevent oxidation of the circuit pattern 144 to improve electrical contact.

The image sensing device 120 is formed with an imaging area 125 for sensing light energy incident from the outside and converting the light energy into an electrical signal. That is, the image sensing device 120 is an imaging device such as a charge-coupled device (CCD) or a complementary metal oxide semiconductor (CMOS).

Flexible Printed Circuit Boards (FPCBs) include a Tape Carrier Package (TCP) or a Chip On Film (COF), etc., depending on the application example to which the image sensor module is applied. An analog-to-digital converter (ADC) circuit for converting an electrical signal, which is an analog signal converted in the imaging area 125, into a digital signal may be disposed.

The base layer 141 of the flexible circuit board 140 and the image sensing device 120 are electrically connected. In this case, they are flip-chip bonded, or wire-bonded, to be electrically coupled to each other.

The image sensing element 120 and the flexible circuit board 140 are bonded to each other by using the flip chip bonding, for example, the bump 130 as a bonding means. That is, as shown in FIG. 3, substrate-side electrode pads 117 and device-side electrode pads 127 are formed on the flexible circuit board 140 and the image sensing device 120, respectively, for electrically connecting to the outside. A bump 130 is formed on the device side electrode pad 127, and the substrate side electrode pad 117 and the adhesive 114 are coupled to each other.                     

Here, the adhesive 114 is a bonding material such as a non conductive paste (NCP), a non conductive particl film (NCF), an anisotropic conductive film (ACF), an anisotropic conductive paste (ACP), and the like on the image sensing element 120. After being applied between the provided bump 130 and the circuit board 110 is thermocompression bonding.

Here, the bump 130 may be a bump of gold material or a bump of nickel-gold material. In this case, there is an advantage in that the adhesion between the bump and the double-sided board is increased and the adhesion area is increased.

Meanwhile, in the present invention, the electromagnetic shielding film 151 is attached to at least one surface of the upper surface 141u and the lower surface 141b of the base layer 141 without being electrically connected to the circuit pattern 144 of the base layer. As a result, the electromagnetic shielding film 151 may not be electrically connected to the driving module ground and the image module ground of the portable device, even when noise is generated from the image sensing device 120 and the devices mounted on the main board of the portable device. It does not act as an antenna of noise, and thus does not adversely affect the image.

In this case, the electromagnetic shielding film 151 may be attached to the base layer 141 with an air gap.

In addition, since the electromagnetic shielding film 151 is not formed integrally by being coated on the base layer 141, the ductility of the flexible circuit board 140 itself is not reduced.

In this case, the electromagnetic shielding film 151 may be attached to the base layer 141 by applying a non-conductive material, for example, an adhesive 161 such as epoxy, or may be fixed using a tape or the like. When the adhesive 161 is used as a fixing means, the adhesive 161 may be attacked and attached by the thickness of the adhesive 161 disposed between the electromagnetic shielding film 151 and the base layer 141.

On the other hand, in order to block the electromagnetic wave or noise introduced into the base layer 141, it is preferable to cover the entire length of the base layer 141, so at least both sides of the electromagnetic shielding film 151 It is preferred that the ends and both ends of the base layer are attached to each other.

 On the other hand, a camera module having an image sensor module 101 including a flexible circuit board having such a structure is shown in FIG. Referring to FIG. 5, the camera module 100 according to the preferred embodiment of the present invention includes an optical system 201 together with the image sensor module 101.

The optical system 201 includes a lens housing 210 and one or more lenses 240. The lens housing 210 has a hollow portion into which the lens holder 220 is inserted. The lens holder 220 includes a lens 240 and is installed in the lens housing 210.

In addition, the camera module 100 may further include a filter 250. The filter 250 blocks the infrared rays incident into the lens housing 210 and prevents the incident light from being reflected. The lower part of the hollow part of the lens housing 210 is installed above the image sensing element 12. An IR-cut coating may be formed on an upper surface of the filter 250, and an anti-reflection coating may be formed on the lower surface of the filter 250 to prevent reflection.

The camera module 100 is connected to the main board of the mobile device through the flexible circuit board 140. In this case, the structure and function of the flexible circuit board 140 is the same as described above.

One example of such a portable device is a mobile phone incorporating a camera module 100. The antenna of the mobile phone is disposed close to the flexible circuit board connecting the camera module and the mobile phone main board. Accordingly, in order to prevent noise from the outside through the antenna from flowing into the devices, a flexible circuit board according to the present invention is required.

According to the present invention having the above structure, the electromagnetic shielding film and the base layer are attacked and bonded to each other, thereby preventing electromagnetic waves and noise from the outside and preventing electromagnetic waves from flowing into the device through the flexible circuit board. By doing so, image quality becomes excellent.

At the same time, the electromagnetic shielding film is disposed with attack on the base layer, thereby ensuring flexibility of the flexible circuit board.

Although the present invention has been described with reference to the embodiments shown in the drawings, this is merely exemplary, and any person skilled in the art to which the present invention pertains may have various modifications and equivalent other embodiments. Will understand. Therefore, the true technical protection scope of the present invention will be defined by the technical spirit of the appended claims.

Claims (8)

A base layer having a plastic film and a circuit pattern formed on at least one of upper and lower surfaces of the plastic film, and a base layer having an insulating layer covering at least the circuit pattern; And And an electromagnetic shielding film attached to at least one of an upper surface and a lower surface of the base layer without being electrically connected to the circuit pattern. The method of claim 1, And an electromagnetic shielding film attached to at least one of the upper and lower surfaces of the base layer and having an attack therebetween. The method of claim 2, An adhesive is disposed between the electromagnetic shielding film and the base layer, and the attack is caused by the thickness of the adhesive disposed between the electromagnetic shielding film and the base layer. The method of claim 1, The electromagnetic wave shielding film is made of the same material as the base layer. Image sensing elements; And The image sensor module of claim 1, further comprising a flexible circuit board having one side surface bonded by the image sensing element and a bonding means. The method of claim 5, And an electromagnetic shielding film attached to at least one of the upper and lower surfaces of the base layer and having an attack thereon. The method of claim 5, The electromagnetic wave shielding film is an image sensor module, characterized in that made of the same material as the base layer. An image sensor module having an image sensing element and a flexible circuit board having a structure as claimed in claim 1 and having a side surface bonded to the image sensing element by a bonding means; And And a lens housing coupled to the image sensor module and having at least one lens mounted thereon.

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