Patent Application
20060290801
1. Field of the Invention
The present invention relates generally to digital camera modules and, more particularly, to a digital camera module which improves image quality.
2. Discussion of the Related Art
Generally, digital cameras are image recording media capable of photographing a plurality of still images without using regular film. Such a digital camera typically uses an image pickup device, which is a kind of semiconductor device, such as a charge coupled device (CCD) or complementary metal oxide semiconductor (CMOS). In the digital camera, an object image formed on the image pickup device through a lens is converted into an electrical signal by the image pickup device, and the electrical signal is stored as a digital signal in a mobile phone or PDA in which the digital camera is mounted.
A digital camera module, as shown in
However, dust and/or particle pollution/contamination associated with friction between the lens barrel 10 and the lens holder 12 may fall onto the image pick-up chip 144, thus affecting image quality of the digital camera module.
What is needed, therefore, is a digital camera module, which overcomes the above-described problem.
A digital camera module comprises a lens holder, a lens mount, and an image pick-up module. The lens holder is hollow, and has at least one lenses received therein. The lens mount is hollow, and an inner diameter of the lens holder being slightly greater than or equal to an outer diameter of the lens mount such that the lens holder capable of locating around the lens mount and movable along an axis of the lens mount. The image pick-up module is arranged to receive the light signal from the lenses.
Other advantages and novel features will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings.
Many aspects of the digital camera module can be better understood with reference to the following drawings. The components in the drawings are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of the present digital camera module. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views.
Referring now to the drawings,
The lens holder 20 is a hollow cylinder in shape with two open ends so that light can be transmitted therethrough. The lens holder 20 includes a first cylinder portion 202, and a second cylinder portion 204 integrally formed with the first cylinder portion 202. An inner diameter of the first cylinder portion 202 is smaller than that of the second cylinder portion 204. The first cylinder portion 202 has a plurality of lenses 206 (only one shown) received therein. The second portion 204 has an internal thread 208 defined in an inner periphery thereof.
The lens mount 22 is a hollow cylinder with two open ends so that light can be transmitted therethrough. The lens mount 22 has a projecting stage 222 projecting from an outer periphery thereof adjacent to a bottom thereof The lens mount 22 has an external thread 224 defined in an outer periphery thereof, corresponding to the internal thread 208 of the lens holder 20.
The base plate 25 is made of a material such as a plastic, a ceramic or a fibrous composite. The base plate 25 has a top surface 250, a bottom surface 252 on an opposite side of the base plate 25 to the top surface 251, a plurality of top pads 251 and a plurality of bottom pads 253. The top pads 251 are arranged in a circular pattern on the top surface 250 of the base plate 25. The bottom pads 253 are arranged in a circular pattern on the bottom surface 252. The base plate 25 is used for electrically connecting the image pick-up chip 27 to other printed circuit boards.
The image pick-up chip 27 attached to the top surface 250 of the base plate 25 via the adhesive means 26, surrounded by the top pads 251. A top side of the image pick-up chip 27 is arranged with a photosensitive area 271 and a plurality of chip pads 272 around the photosensitive area 271.
The bonding wires 28 are made of a conductive material such as gold or aluminum alloy. One end of each bonding wire 28 is connected/joined with a respective chip pad 272 of the image pick-up chip 27, and the other end of the bonding wires 28 is connected/joined with a respective top pad 251 of the base plate 25.
The adhesive means 26, such as a silicone, epoxy, acrylic, or polyamide adhesive, is also applied peripherally around the image pick-up chip 27, over the bonding wires 28. The adhesive means 26 covers the bonding wires 28 and junctions of the bonding wires 28 and the pads 272, 251, in order to protect the bonding wires 28 from cracking from metal fatigue and to ensure the firm connection between the ends of the bonding wires 28 and pads 272, 251. It is to be understood that the adhesive means 26 could be applied to the peripheral edge of the image pick-up chip 272 and/or over the bonding wires 28, therefore the adhesive means 26 covers part of each bonding wire 28 and junctions between the bonding wire 283 and the chip pads 272.
In assembling the digital camera module 100, the lens holder 20 is placed around the lens mount 22, with the internal thread 208 engaging with the external thread 224 of the lens mount 22. Then, the lens mount 22 is fixed on the image pick-up module 24, with the image pick-up chip 27 received in the lens mount 22 and the lens mount 22 secured on the base plate 25. During auto-focusing, a distance between the lens holder 20 and the image pick-up chip 27 is slightly adjusted to focus the digital camera module 100 by adjusting the thread engagement of the internal thread 208 of the lens holder 20 and the external thread 224 of the lens mount 224.
Referring to
The lens holder 30 is a hollow cylinder in shape with two open ends so that light can be transmitted therethrough. The lens holder 20 includes a first cylinder portion 302, and a second cylinder portion 304. An inner diameter of the first cylinder portion 302 is smaller than that of the second cylinder portion 304. The cylinder portion 302 has a plurality of tenses 306 (only one shown) received therein. The second portion 304 has an internal thread 308 defined in an inner periphery thereof.
The lens mount 32 is a hollow cylinder with two open ends so that light can be transmitted therethrough. The lens mount 32 includes an upper cylinder portion 321, and a lower cylinder portion 322 extending from an outer periphery of the upper cylinder portion 321. An inner diameter of the lower cylinder portion 321 is larger than that of the upper cylinder portion 321. The upper cylinder portion 321 has an external thread 324 defined in an outer periphery thereof, corresponding to the internal thread 308 of the lens holder 30.
The base plate 35 is made of a material such as a plastic, a ceramic or a fibrous composite. The base plate 35 has a top surface 351, and a bottom surface 352.
The flange 36 is a hollow rectangle in shape, and includes an upper surface 362 and a lower surface 364. The lower surface 364 is adhered to the top surface 351 of the base plate 35, defining a receiving space 346 with the base plate 35.
The image pick-up chip 38 is adhered to the top surface 351 of the base plate 35 via the adhesive means 37. A top side of the image pick-up chip 38 is arranged with a photosensitive area 381 and a plurality of chip pads 382 around the photosensitive area 381.
The bonding wires 39 is same as the bonding wires 28. One end of each bonding wires 38 is connected/joined with a respective chip pad 382 of the image pick-up chip 38, and the other end of the bonding wires 39 is connected/joined with the metal plate 41.
The metal plate 41 has a first plate portion 411, a second plate portion 413 parallel to the first plate portion 411, and a third plate portion 412 connecting with the first plate and the second plate portion 413. The first plate portion 411 is placed on the upper surface 362 of the flange 36. The second plate portion 413 is adhered to the lower surface 364 of the flange 36. The third plate portion 412 is jointed to a side of the flange 36. The first plate portion 411 electrically connects with the bonding wires 39, and the second plate portion 412 electrically connects with a printed circuit board.
The transparent plate 40 may be a transparent glass, and is fixed on the metal plate 41, thus sealing the photosensitive area 381 of the image pick-up chip 38.
In assembling the digital camera module 200, the lens holder 30 places around the lens mount 32, with the internal thread 308 engaging with the external thread 324 of the lens mount 32. Then, the lens mount 32 is fixed on the image pick-up module 34, with the transparent plate 40 securely received in a bottom of the lens mount 32. During auto-focusing, a distance between the lens holder 30 and the image pick-up chip 38 is adjusted to focus the digital camera module by adjusting the thread engagement of the internal thread 308 of the lens holder 30 and the external thread 2324 of the lens mount 32.
In the embodiments, since the thread engagement between the lens holder and the lens mount is disposed on outer periphery of the lens mount, dust and/or particle pollution/contamination associated with friction between the lens holder and the lens mount can be effectively prevented from entering the pick-up module. In the second embodiment, a transparent plate 40 is disposed on the image pick-up chip 38 to completely prevent particles or dust from falling onto the image pick-up chip 38, thus improving image quality of the digital camera module.
It is to be understood, however, that even though numerous characteristics and advantages of the present embodiments have been set forth in the foregoing description, together with details of the structures and functions of the embodiments, the disclosure is illustrative only, and changes may be made in detail, especially in matters of shape, size, and arrangement of parts within the principles of the invention to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.
| Number | Date | Country | Kind |
|---|---|---|---|
| 200510035555.0 | Jun 2005 | CN | national |
