WO2005084012A1

WO2005084012A1 - Camera module

Info

Publication number: WO2005084012A1
Application number: PCT/KR2004/001994
Authority: WO
Inventors: Sung-Min Kim; Kyung-Sik Kim; Bung-Sun Choi
Original assignee: Ids Co., Ltd.
Priority date: 2004-02-26
Filing date: 2004-08-07
Publication date: 2005-09-09
Also published as: TW200528902A; KR20050087186A; KR100593555B1; TWI269925B

Abstract

A camera module for mobile phone is disclosed. The camera module for mobile phone comprises a housing 10 being opened at a lower portion thereof, and formed, at the center of an upper portion thereof, with an opening to be engaged with a lens 11, a ceramic package 20 bonded to the lower portion of the housing 10, mounted with an image sensor 21 therein, and having an opened upper portion of the ceramic package 20, a filter 30 covering the upper portion of the ceramic package 20 for shielding against infrared radiation incident on the upper portion of the ceramic package 20, and a circuit substrate bonded to a lower portion of the ceramic package and mounted with a chip 51 for driving the image sensor thereon. The housing 10 consists of metal or a metallic alloy, and an inner surface thereof is subjected to surface treatment by means of an anodizing method or is coated with chrome. The camera module for mobile phone has enhanced electrical and thermal stabilities, extended life span, and enhanced image quality.

Description

Description CAMERA MODULE Technical Field

[1] The present invention relates to a camera module for mobile phone , and more particularly to a camera module for mobile phone, which has a housing made of a material different from that of a conventional camera module for mobile phone or subjected to a chemical treatment, and a ceramic member provided on a circuit substrate, so that an image sensor in the camera module for mobile phone can be protected from electrical noise inside the camera module or from external environmental factors.

[2] Background Art

[3] An image sensor of a camera module for mobile phone, which carries out a very important function in the camera module, is a device for picking-up information of a subject and converting the picked-up information into an electrical image signal. The image sensor comprises an image pick-up tube and a solid image sensor.

[4] For the solid image sensor, a Complimentary Metal Oxide Semiconductor (CMOS) or a Charge Coupled Device (CCD) is employed. When using the CMOS, the solid image sensor comprises a photoelectric transformation semiconductor, and a CMOS switch, which carries out an operation for reading charges generated by light energy. The solid image sensor employing the CMOS has merits of lower power consumption and being capable of being formed as a single IC chip. However, it has disadvantages in that there oxurs a lot of noise.

[5] Meanwhile, when using the CCD, the solid image sensor comprises the photoelectric transformation semiconductor, and the CCD, which carries out an operation for accumulating the charges generated by light energy and then transferring the accumulated charges. The solid image sensor employing the CCD has merits of excellent image quality and of high sensitivity. However, it has disadvantages in that it is very expensive and has complicated surrounding circuits.

[6] Since the image sensor as described above serves to carry out a very important function, such as determination of image quality, it is very important that the image sensor be influenced as little as possible by internal or external conditions.

[7] In addition to the image sensor for converting light into electrical signals, the camera module for mobile phone generally comprises a housing for protecting the image sensor or for mounting a lens, a filter for filtering the light entering from the lens, and a circuit substrate with a chip mounted thereon for driving the image sensor.

[8] In such a conventional camera module for mobile phone as mentioned above, the housing is formed of a typical injection moulded structure made of plastic material. The housing protects the inside of the camera module from the outside thereof by means of shielding the inside of the camera module for mobile phone from the outside thereof by coating the injection moulded structure with aluminium using vacuum coating technology or by coating the injection moulded structure using a spraying method, followed by curing the coating of the injection moulded structure under heat.

[9] However, according to the conventional technologies, the problems of internal noise generated from the image sensor chip or external electrical problems, such as electromagnetic waves, cannot be thoroughly solved. Furthermore, since the plastic material has a weak heat resistance, influence on the camera module caused by heat from the outside cannot be thoroughly prevented.

[10] Disclosure of Invention Technical Solution

[11] The present invention has been made to solve the above problems, and it is an object of the present invention to provide a camera module for mobile phone, which comprises a housing made of a material, and having a structure, different from those of the housing of the conventional camera module for mobile phone, and a ceramic member provided on a circuit substrate, thereby eliminating environmental and electrical influence from the outside thereof, resulting in enhanced image quality of the camera module.

[12] In accordance with one aspect of the present invention, the above and other objects can be accomplished by the provision of a camera module for mobile phone, comprising: a housing opened at a lower portion thereof, and formed, at the center of an upper portion thereof, with an opening to be engaged with a lens; a ceramic package bonded to the lower portion of the housing while being opened at an upper portion of the ceramic package, and including an image sensor therein; a filter covering the upper portion of the ceramic package for shielding against infrared radiation incident on the upper portion of the ceramic package; and a circuit substrate bonded to a lower portion of the ceramic package with a chip for driving the image sensor mounted thereon.

[13] The housing may consist of metal or a metallic alloy, and the metal may be one selected from aluminum, magnesium and molybdenum. [14] The housing may have an inner surface thereof subjected to surface treatment by anodizing or coated with chrome. [15] The ceramic package may comprise an inner lead line for electrically connecting the image sensor and the circuit substrate. [16] The circuit substrate may comprise a ceramic substrate and an FPCB.

[17] Brief Description of the Drawings [18] The above and other objects, features and other advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which: [19] Fig. 1 is a cross sectional view of a camera module for mobile phone according to a first embodiment of the present inventionFig. 2 is an exploded view of the camera module for mobile phone according to the first embodiment; [20] Fig. 3 is a cross sectional view of a camera module for mobile phone according to a second embodiment of the present inventionFig. 4 is an exploded view of the camera module for mobile phone according to the second embodiment; and [21] Fig. 5 is an enlarged view of circles A in Figs. 1 and 3, showing a coating formed by anodizing an inner surface of the camera module of the present invention. [22] Best Mode for Carrying Out the Invention [23] Now preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily understand and repeat the present invention. [24] Fig. 1 is a cross sectional view of a camera module for mobile phone according to a first embodiment of the present invention, and Fig. 2 is an exploded view of the camera module for mobile phone according to the first embodiment. [25] As shown in Figs. 1 and 2, the camera module for mobile phone comprises: a housing 10 engaged with a lens 11; a ceramic package 20 bonded to the housing 10 at a lower portion of the housing 10 and mounted with an image sensor 21 therein; a filter 30 covering an upper portion of the ceramic package 20 for shielding against infrared radiation incident on the upper portion of the ceramic package; and a circuit substrate with a chip 51 mounted thereon for driving the image sensor 21. [26] The housing 10 is formed by a process separate from that of manufacturing the ceramic package 20. As shown in Fig. 2, the housing 10 is opened at a lower portion thereof, and formed, at an upper portion thereof, with an opening 13 having a predetermined size. The opening 13 is adapted to be engaged with a lens 11.

[27] The housing 10 is formed of metal, such as aluminum (Al), magnesium (Mg) or Molybdenum (Mo), or alloys thereof. As the housing 10 is formed of the metal, such as aluminum (Al) or the like, it can be ensured that the camera module satisfies requirements for thermal stability, moisture resistance and contaminant resistance.

[28] Meanwhile, in order to protect the inside of the camera module, an appropriate chemical treatment is performed on an inner surface of the housing 10. Specifically, during the process of manufacturing the housing 10, after embossing the inner surface of the housing 100 by precisely etching the inner surface of the housing 100 formed of the metal, such as aluminum, using predetermined chemicals, surface treatment is applied to the inner surface of the housing by means of anodizing, otherwise, Cr is coated on the inner surface of the housing.

[29] Meanwhile, the inner surface of the housing is subjected to surface treatment by mean of anodizing or coated with Cr, without embossing the inner surface of the housing.

[30] Fig. 5 is an enlarged view of circles A in Figs. 1 and 3. In Fig. 5, the inner surface of the camera housing 170 is etched to form a micro-etched interface 171, and is then subjected to surface treatment using anodizing to form an anodized coat 172.

[31] As described above, the inner surface of the housing 10 is coated with chrome or is anodized, shielding electromagnetic waves and static electricity, thereby protecting the inside of the camera module for mobile phone and enhancing image quality of the camera module.

[32] The ceramic package 20 is made by another process different from the process of manufacturing the housing 10. As shown in Fig. 2, the ceramic package is opened at an upper portion thereof and is bonded to the circuit substrate at a lower portion of the ceramic package. The opened upper portion of the ceramic package 20 is closed by the filter 30 serving to shield the infrared radiation, and coupled to the housing 10 at the lower portion of the housing 10 by bonding. The ceramic package 20 comprises the image sensor 21 employing a CCD (Charge Coupled Device) or a CMOS (Complementary Metal Oxide Semiconductor).

[33] It is necessary to protect the image sensor from the influence of internal or external conditions of the camera module. Accordingly, the image sensor is protected by the ceramic package 20 such that the image sensor can be isolated from the outside.

[34] Meanwhile, the ceramic package 20 comprises a lead line 22 therein for electrically connecting the image sensor 21 and the circuit substrate. Specifically, in order to electrically connect the lead line 22 connected to the image sensor and a printed circuit formed on the circuit substrate, the ceramic package 20 may be formed with the lead line therein.

[35] As shown in Figs. 1 and 2, the circuit substrate comprises a ceramic substrate 40, a flexible printed circuit board (FPCB) 50, a chip 51, such as an ISP (Image Signal Processor) or DSP (Digital Signal Processor), for driving the image sensor 21, and various passive devices 52 and 53 required for circuit operation. Meanwhile, the circuit substrate is shielded from the outside by a molding process to a lower portion of the circuit substrate, as is indicated by reference numeral 60 or 160 in Figs. 1 to 4.

[36] As shown in Fig. 2, the ceramic substrate 40 is formed between the ceramic package 20 and the FPCB 50, and bonded to the lower portion of the ceramic package. As such, with the ceramic substrate 40, the FPCB 40, the various kinds of passive device 52 and 53, and the chip 51, such as the DSP, are separated from the ceramic package 20 with the image sensor 21 mounted thereon, so that it can minimize influences of heat generated by the passive devices 52 and 53 on the image sensor 21. That is, the ceramic package 20 made of the ceramic material and the ceramic substrate 40 are bonded to each other as double layers, so that the image sensor 21 is not influenced by the heat generated from the passive devices.

[37] Meanwhile, although, as for the circuit substrate, a printed circuit board (PCB) is conventionally used, the circuit substrate of the present invention is formed using the ceramic substrate 40 and the FPCB 50, as described above, in order to enhance the function of the camera module or to reduce the size thereof.

[38] With regard to a process for manufacturing the circuit substrate, first, a die bonding process is performed for attaching the DSP chip or the ISP chip, followed by a wire bonding process, which is performed for enabling current to flow between the DSP chip or the ISP chip and the circuit substrate. Then, a process for forming the passive devices for driving the DSP chip or the ISP chip, and a molding process are sequentially performed, thereby providing a completed circuit substrate.

[39] Fig. 3 is a cross sectional view of a camera module for mobile phone according to a second embodiment of the present invention, which has a structure different from that shown in Figs. 1 and 2, and Fig. 4 is an exploded view of the camera module for mobile phone according to the second embodiment.

[40] As shown in Figs. 3 and 4, the camera module for mobile phone comprises: a housing 110 coupled with a lens 111; a ceramic package 120 bonded to the housing 110 at a lower portion of the housing and with an image sensor 121 mounted therein; a filter 130 covering an upper portion of the ceramic package 120 for shielding against infrared radiation incident on the upper portion of the ceramic package 120; and a circuit substrate with a chip 151 for driving the image sensor 121 mounted thereon.

[41] The camera module for mobile phone according to the second embodiment has a configuration similar to that of the camera module for mobile phone according to the first embodiment, except for the configuration of the ceramic package 120 and the circuit substrate. Specifically, as shown in Figs. 3 and 4, the ceramic package 120 has an "H"-shape, so that the ceramic package is opened at upper and lower portions thereof. The ceramic package is closed by the filter 130 at the upper portion of the ceramic package, and closed by the ceramic substrate 140 at the lower portion of the ceramic package. The chip 151, such as the ISP or the DSP, is located in the ceramic package 120.

[42] As in the first embodiment of the present invention, in the structure of the camera module of the second embodiment shown in Figs. 3 and 4, the ceramic package 120 is bonded, at the lower portion thereof, to the ceramic substrate 140. The ceramic substrate 140 is formed, at the top surface of the ceramic substrate 140, with the chip 151, such as the ISP or the DSP, and is formed, at the bottom surface thereof, with an FPCB 150 and various passive devices 152 and 153. Accordingly, the ceramic substrate can minimize the influences of heat generated from the passive device 152 and 153 on the camera module.

[43] As for a process for manufacturing the housing or the ceramic package, there are various methods, including an extrusion process, a process using a cast-iron, a machining process, and a stamping process, which automatically completes the product through several stages by means of press equipment and molds.

[44] As is apparent from the above description, according to the present invention, the inner surface of the housing of the camera module for mobile phone is formed of metal or alloys, which surface treatment using the anodizing method is applied, so that the camera module for mobile phone has enhanced electrical stability, extended life span, and enhanced image quality.

[45] Further, the housing of the camera module is formed of the plastic material and is then coated with aluminum thereon, thereby not only solving the problems of thermal instability and weakness to contamination from the external environment, but also reducing electromagnetic waves.

[46] It should be understood that the embodiments and the accompanying drawings as described above have been described for illustrative purposes and the present invention is limited by the following claims. Further, those skilled in the art will appreciate that various modifications, additions and substitutions are allowed without departing from the scope and spirit of the invention as set forth in the accompanying claims.

Claims

[1] A camera module for mobile phone, comprising: a housing opened at a lower portion thereof, and formed, at the center of an upper portion thereof, with an opening to be engaged with a lens; a ceramic package bonded to the lower portion of the housing while being opened at an upper portion of the ceramic package, and including an image sensor therein; a filter covering the upper portion of the ceramic package for shielding against infrared radiation incident on the upper portion of the ceramic package; and a circuit substrate bonded to a lower portion of the ceramic package with a chip for driving the image sensor mounted thereon. [2] The camera module as set forth in claim 1, wherein the housing consists of metal or a metallic alloy. [3] The camera module as set forth in claim 2, wherein the metal is one selected from aluminum, magnesium and molybdenum. [4] The camera module as set forth in claim 1 or 2, wherein the housing has an inner surface subjected to surface treatment by anodizing. [5] The camera module as set forth in claim 4, wherein surface treatment by anodizing is applied to the inner surface of the housing after embossing the inner surface of the housing. [6] The camera module as set forth in claim 1 or 2, wherein the housing has an inner surface coated with chrome. [7] The camera module as set forth in claim 6, wherein the housing has the inner surface coated with chrome after embossing the inner surface of the housing. [8] The camera module as set forth in claim 1, wherein the ceramic package comprises an inner lead line for electrically connecting the image sensor and the circuit substrate. [9] The camera module as set forth in claim 1, wherein the circuit substrate comprises a ceramic substrate, an FPCB, a DSP chip, and passive devices, the ceramic substrate being bonded to the ceramic package at a lower portion of the ceramic package.