WO2008129460A1

WO2008129460A1 - Camera module

Info

Publication number: WO2008129460A1
Application number: PCT/IB2008/051436
Authority: WO
Inventors: Menno B. Kubbinga
Original assignee: Penta Optics B.V.
Priority date: 2007-04-20
Filing date: 2008-04-15
Publication date: 2008-10-30

Abstract

A camera module (1) comprises a holder (2), an optical module (3) mounted in said holder (2) and a filter (6) connected to said holder (2) by an adhesive. The holder (2) is provided with at least one elongated air passage (11) located at least partly between the holder (2) And the filter (6) and the elongated air passage (11) between the holder (2) and the filter (6) is partly narrowed.

Description

CAMERA MODULE

FIELD OF THE INVENTION

The invention relates to a holder, an optical module mounted in said holder and a filter connected to said holder by an adhesive.

BACKGROUND OF THE INVENTION

Such a camera module can for example be used for the mobile phone camera market, whereby an imager chip is connected to the holder on a side of the filter remote from the optical module. By such an application it is important that no foreign loose particles, bigger than for example 10 μm are present in the space bounded by the holder, the filter and the imager chip.

Furthermore it has to be noticed that normally such an imager chip is connected to the holder at a relatively high temperature causing air to expand. It is important that the air pressure on both sides of the filter is almost equal to ensure optimal functioning of the camera module.

SUMMARY OF THE INVENTION

It is an object of the invention to provide a camera module whereby the air pressure on both sides of the filter can easily be balanced, whereby relatively large particles are prevented from moving to the side of the filter remote from the optical module.

This object is achieved by a camera module according to the invention in that the holder is provided with at least one elongated air passage located at least partly between the holder and the filter, whereby the elongated air passage between the holder and the filter is partly narrowed.

Due to the air passage, pressure on both sides of the filter can easily be equalized. Since the elongated air passage is partly narrowed, relatively large particles, for example bigger than 10 μm, are prevented from moving from the optical module to a side of the filter directed away from the optical module. Larger particles, up to for example 40 μm, may enter the elongated air passage but are prevented from moving to the side of the holder which will be connected to the imager chip and will be "caught" in the narrowed air passage.

An embodiment of the camera module according to the invention is characterized in that the elongated air passage is U-shaped, comprising two elongated relatively deep channels and an elongated relatively shallow channel connecting the two deep channels, whereby the elongated air passage is partly narrowed by a U-shaped barrier comprising two leg parts located in the deep channels and a bridge part extending between the two leg parts and located in the shallow channel. Due to said U-shaped barrier the elongated air passage can easily be narrowed, whereby the dimensions of the air passage on both sides of the barrier can be relatively large to enable relatively large particles to be collected in the air passage.

The dimensions of the air passage as well as of the U-shaped bridge are chosen such that particles of a certain size are prevented from moving across the air passage whilst maintaining a gap for air venting. Furthermore it must be ensured that adhesive used for connecting the filter to the holder will not block the air passage.

Yet another embodiment of the camera module according to the invention is characterized in that the U-shaped barrier has a relatively rough surface.

Due to the rough surface of the U-shaped barrier, relatively small particles will be caught by the U-shaped barrier and will stay attached to the U-shaped barrier so that these particles are maintained out of the optical light way between the optical module and the imager chip.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will now be explained in more detail with reference to the drawings in which:

Fig. 1 is a perspective top view of the camera module according to the invention,

Fig. 2 is a perspective bottom view of the camera module of Fig. 1, Fig. 3 is a cross section of the camera module of Fig. 1,

Fig. 4 is a bottom view of the camera module of Fig. 1, Fig. 5 is a cross section V-V of the camera module of Fig. 4, Fig. 6 is a cross section of the air passage of the camera module according to the invention, whereby the air passage is not narrowed, Fig. 7 is a cross section of the air passage of Fig. 6, whereby the air passage is narrowed.

Like parts are indicated by the same reference numbers in the Figures.

DETAILED DESCRIPTION OF EMBODIMENTS

Figs. 1-5 show different views of the camera module 1 according to the invention, which camera module 1 comprises a holder 2 in which an optical module 3 is mounted. The optical module 3 comprises a carrier 4 with three lenses 5. The lenses 5 are connected to the carrier 4, which carrier 4 is mounted by means of thread in the holder 2. The camera module 3 also comprises an IR filter 6 which filter 6 is connected to flanges 7 of the holder 2 by means of an adhesive, such as for example glue.

The camera module 1 furthermore comprises an imager chip (not shown) which is connected to an edge 8 of the holder 2 on the side of the IR filter 6 remote from the optical module 3. To ensure that the air pressure in the space 9 between the optical module 3 and the IR filter 6 equals the air pressure in the space 10 between the IR filter 6 and the imager chip (not shown) air passages 11 are provided in the holder 2 to allow air to flow in the direction as indicated by the double arrow Pl. On each side of each air passage 11 ribs 12 are provided to which the IR filter 6 abuts and which prevent that the air passage 11 is being blocked by the IR filter 6.

Figs. 6 and 7 show enlarged views of the air passage 11 and are cross sections VI-VI and VII-VII of the holder 2 as shown in fig. 4 whereby the IR filter 6 is attached to the holder 2.

Each air passage 11 comprises two elongated relatively deep channels 13 formed in the flange 7 of the holder 2 and a shallow channel 14 extending parallel to the channels 13 and connecting the channels 13 to each other. The shallow channel 14 is formed in the flange 7 by an elongated strip 15. The air passage 11 comprising the deep channels 13 and the shallow channel 14 can be formed in the flange 7 of the holder 2 by spark erosion, milling etcetera. The elongated air passage 11 is partly blocked by a U-shaped barrier 16 comprising two leg parts 17 located in the deep channels 13 and a bridge part 18 extending between the leg parts 17. The bridge part 18 is located in the shallow channel 14. Due to the U-shaped barrier 16, the narrow channels 13 and shallow channel 14 of the air passage 11 are partly blocked thereby reducing the dimensions of the air passage 11 to such an extend that for example foreign particles larger than 10 μm will not be able to move through the whole air passage 11.

The U-shaped barrier 16 preferably has a relatively rough surface due to which particles will attach to the barrier 16 and will be prevented from moving back to the optical module 3. The rough surface surface has a roughness for example according to ISO 1302, N6-N10.

The barrier 16 is moulded together with the holder 2 and is therefore made of the same material as the holder.

The U-shaped barrier 16 is located between the flange 7 of the holder 2 and the IR filter 6, whereby the dimensions of the air passage 11 both at the location of the U- shaped barrier 16 as well as on a distance thereof are such that the adhesive by means of which the IR filter 6 is being connected to the holder 2 is prevented to block the air passage 11.

The distance between the barrier 16 and the IR- filter 6 is 10 μm so that particles larger than 10 μm will be stopped.

It should be noted that the above-mentioned embodiments illustrate rather than limit the invention, and that those skilled in the art will be able to design many alternative embodiments without departing from the scope of the appended claims. In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. The word "comprising" does not exclude the presence of other elements or steps than those listed in a claim. The word "a" or "an" preceding an element does not exclude the presence of a plurality of such elements.

Claims

CLAIMS:

1. Camera module (1) comprising a holder (2), an optical module (3) mounted in said holder (2) and a filter (6) connected to said holder (2) by an adhesive, characterized in that the holder (2) is provided with at least one elongated air passage (11) located at least partly between the holder (2) and the filter (6), whereby the elongated air passage (11) between the holder (2) and the filter (6) is partly narrowed.

2. Camera module (1) according to claim 1, characterized in that the elongated air passage (11) is U-shaped, comprising two elongated relatively deep channels (13) and an elongated relatively shallow channel (14) connecting the two deep channels (13), whereby the elongated air passage (11) is partly narrowed by a U-shaped barrier (16) comprising two leg parts (17) located in the deep channels (13) and a bridge part (18) extending between the two leg parts (17) and located in the shallow channel (14).

3. Camera module (1) according to claim 2, characterized in that the U-shaped barrier (16) is fully located between the holder (2) and the filter (6).

4. Camera module (1) according to one of the preceding claims, characterized in that the U-shaped barrier (16) has a relatively rough surface.

5. Camera module (1) according to one of the preceding claims, characterized in that the narrowed elongated air passage (11) has an opening of about 10 μm.

6. Camera module (1) according to one of the preceding claims, characterized in that an imager chip is connected to the holder (2) on a side of the filter (6) remote from the optical module (3).