GB2403290A

GB2403290A - Method and apparatus for adjusting lenses

Info

Publication number: GB2403290A
Application number: GB0315072A
Authority: GB
Inventors: Nien-Ting Weng; Kuo Wen Chang
Original assignee: Nucam Corp
Current assignee: Nucam Corp
Priority date: 2003-06-27
Filing date: 2003-06-27
Publication date: 2004-12-29
Also published as: FR2857462B3; GB0315072D0; FR2857462A3

Abstract

In the manufacture of a digital camera, a translation carrier 30 having an aperture 31 is placed on a housing 10 containing an optical sensor 20 such as a CCD. A lens group 40 is the placed on the translation cater, aligned with the aperture. In order to axially align the lens group 40 with the centre of the optical sensor 20, the translation carrier is horizontally adjustable and the lens group is rotatable. The lens group may be held within a drawtube to protect the lenses, in which case the drawtube is rotatable.

Description

Method and Mechanism for Adjusting Lens [00011 The invention generally

relates to a method and mechanism for adjusting lens for adjusting the perpendicularity of the lens optical axis to the image sensor surface at the center of the image sensor and in particular to a method and mechanism for simplifying the adjusting process, reducing number of parts of the mechanism and cost of products.

10002] Generally, an optical imaging product commonly comprises lens group image sensor and so on. During products manipulated, such as in the course of producing digital camera, in order to obtaining clear image, it is very important to insure the axis of lens group vertically aligned with the center of the image detected area (IDA) of the image sensor.

3] Till now, it is very difficult to insure the axis of lens group vertically and precisely aligned with the center of the image detected area of the image sensor in the course of producing digital camera. For example, a factory producing digital camera commonly will not manufacture all assemblies. The image sensor such as CCD or CMOS will be packaged and tested in the package factory after it was made in semiconductor foundry. However, finally integrating manufacturer finds that, under commonly manufacturing process, the axis of lens group is not vertically and precisely aligned with the center of the image detected area of the image sensor. The chip's location is not fixed exactly in the course of package housing.

100041 Because the location error can not be corrected after sensor packaged, at present, the method for correcting the location error is to adjust the lens. Please refer to FIG.5 and FIG.6. FIG.5 and FIG.6 illustrate a method to adjust lens by screw and screw. It is necessary to adjust two screws at the same time. FIG.7 shows another embodiment to adjust lens, which adjusts the screw and urges the spring. When every adjustment is completed, operators have to wait until the spring forces the lens at a steady state. Then, the location of the lens is measured to confirm whether the axis of lens group is vertically and precisely aligned with the center of the image sensor or not. If not, the operator has to adjust again. Such method is not convenience, and increases additional assemblies like screw, spring and so on.

100051 The location error is not too large (horizontal error is about 0.2mm, vertical error is about [degree) and the image detected area of the image sensor is very small(image detect area is about 12sq.mm. 20sq.mm.). For decreasing the cost, the image bug caused by the optical axis of lens vertically deviates from the center of the image detected area is ignored in the course of low price digital camera designed and produced, 100061 An object of the present invention is to provide a mechanism for adjusting lens which comprises lens group, translation-carrier, image- housing which allow the lens group and the translation-carrier to be adjusted, so that the axis of lens group would be vertically and precisely aligned with the center of the image sensor with simple assemblies.

100071 Another object of the present invention is to provide a method for adjusting lens in which the lens group and the translation-carrier is adjusted before fixing, so that the axis of lens group can be easily aligned with the center of the image sensor with simple steps and operation.

10008] In accordance with the present invention, the method for adjusting lens comprises the following steps: providing a sensor-housing which containing an image sensor; placing a translation-carrier on the sensorhousing; locating a lens group on the translation-carrier; horizontally moving the translation-carrier for eliminating horizontal offset of the lens; rotating the lens group for eliminating the vertical incline of the axis of lens group to the center of the image sensor; and fixing the sensor-housing, the translation-carrier and the lens group, so that the adjustment can be easily executed.

[00091 The mechanism for adjusting lens of the invention comprises a sensor-housing; an image sensor contained in the sensor-housing; a translation-carrier placed on the sensor-housing and a lens group disposed on the translation-carrier; the translation-carrier having an aperture formed in the central section thereof to allow the lens group disposed thereon.

0] As described above, the present invention will simplify the process, reduce number of parts, save volume and weight of the products, and in particular suit for manufacturing mobile products such as Notebook computer Mobile Phone and so on.

10011] The present invention will be apparent to those skilled in the art by reading the following description of a preferred embodiment thereof, with reference to the attached drawings, in which: 10012] FIG. 1 is a schematic view of the first embodiment of the mechanism for adjusting lens of the present invention; l0013l FIG. 2 is a schematic view of the second embodiment of the mechanism for adjusting lens of the present invention; lO014] FIG. 3 is a schematic view of the third embodiment of the mechanism for adjusting lens of the present invention; l0015l FIG. 4 is a schematic view of the fourth embodiment of the mechanism for adjusting lens of the present invention; 00161 FIG. 5 is a schematic view of an embodiment of the prior art; [0017] FIG. 6 is a partially cross-sectional view of the FIG.5; 100181 FIG.7 is a partially cross-sectional view of another

embodiment of the prior art.

[00191 Referring to FIG.I, a first embodiment ofthe present invention is disclosed. A mechanism 100 for adjusting lens of the present invention comprises a sensor-housing 10, an image sensor 20 contained in the sensorhousing 10, a translation-carrier 30 placed on the sensor-housing 10 and a lens group 40 including a first lens 41 and a second lens 42 engaged together and disposed on the translation-carrier 30. An aperture 31 is formed in the central section of the translation- carrier 30 and allows light to transmit from objects to the image sensor 20 within the sensor-housing 10 via the aperture 31, thus, the image sensor 20 captures images of the objects. The underside 48 of the second lens 42 is disposed on the translation-carrier 30. The translation- carrier 30 can be moved relative to the sensor-housing 10.

The lens group 40 can be moved relative to the translation-carrier 30.

Therefore, the lens group 40 can be precisely adjusted and aligned with the center of the image sensor 20.

[00201 Referring to FIG.2, which shows second embodiment of the invention. The mechanism 100 for adjusting lens comprises a sensor-housing 10, an image sensor 20 contained in the sensor-housing 10, a translation-carrier 30' placed on the sensor-housing 10, lens group 40' including a first lens 41' and a second lens 42' engaged together and disposed on the translation-carrier 30'. An aperture 31' is formed in the central section of the translation-carrier30'. The mechanism 100 of the second embodiment is similar to that of the first embodiment. In the second embodiment, the translation-carrier 30' further has a brim 32' which upwardly extends from the edge of the aperture 31'. As shown in FIG. I, the underside 48 of the first lens 41 is convex, the aperture 31 is just a simple perforation and the underside 48 enters into the aperture 31, so that the first lens 41 is adjustable disposed on the translation- carrier 30. As shown in FIG.2, the underside 48' of the first lens 41' is concave, the underside 48' covers with the brim 32 so that the first lens 41' is adjustable disposed on the translation-carrier 30'.

When lens group 40 or 40' deviates from the vertical, lens groups 40 or 40' can steadily sit on the translation-carrier 30 or 30'.

[00211 FIG.3 and FIG.4 illustrate third and fourth embodiments of the present invention. To prevent the lenses from being rubbed while adjusting lens groups or the lenses from being incompletely agglutinated, the mechanism 100 for adjusting lens of the present invention further comprises a drawtube 44 or 44'. The drawtube 44 or s 44' receives the lens group 40 or 40', which includes first lens 41 or 41' and second Icns42 or 42'. The drawtube 44 or 44' comprises a cylinder 46 or 46' and a underside portion 48" or 48"'. The underside portion 48" or 48"' of the drawtube 44 or 44' can be convex or concave in order to comply with the first lens 41 or 41' and disposed on the translation- carrier 30 or 30'. The lens groups 40,40' are received in and protected by the drawtube 44 or 44', when adjusting.

100221 The method for adjusting lens of the present invention comprises the following steps: a: providing a sensor-housing which containing an image sensor; b: placing a translation-carrier on the sensor-housing, the a translation-carrier having a aperture formed in the central section thereof; c: locating a lens group on the translation-carrier; d: according to the position offset of the image sensor and the lens group, horizontally moving the translation-carrier for eliminating horizontal offset of the lens; e: according to the angle offset of the image sensor, rotating the lens group for eliminating the vertical incline of the axis of lens group to the center of the image sensor (rotating around x y axis) to make the axis of lens group vertically aligned with the center of the image sensor more precise; f: fixing sensor-housing, translation-carrier and lens group, so that the axis of lens is vertically aligned with the center of the image sensor.

100231 in assembly, the translation-carrier is placed on the sensorhousing, then, the lens group is located on the translation-carrier.

Alternatively, the lens group is located on the translation-carrier, then, the translation-carrier is placed on the sensor-housing.

100241 The sequence of the steps described above can change as: according to the angle offset of the image sensor, rotating the lens group for eliminating the vertical incline of the axis of lens group to the center of the image sensor; then, according to the position offset of the image sensor, horizontally moving the translation-carrier' for eliminating horizontal offset of the lens. The steps described above can be done at the same time, that is, while horizontally moving the translation-carrier for eliminating horizontal offset of the lens, rotating the lens group for eliminating the vertical incline of the axis of lens group to the center of the image sensor.

10025] For protecting the lens group, the step c as described above is changed as follow: c: providing a drawtube which contains lens group therein and locating the drawtube on the translation-carrier. The step e is changed as follow: according to the angle offset of the image sensor, rotating the drawtube for eliminating the vertical incline of the axis of lens group to the center of the image sensor. The lens is protected by the drawtube. Therefore, the lens would not be robbed when rotating the drawtube.

6] This invention has been described with reference to specific embodiments, this description is not to be construed in a limiting sense.

For example, those skilled in the art will recognize modifications and alterations which may be made to the embodiments illustrated herein.

Flowever, it is contemplated that such modifications can be made without departing the scope and spirit of the invention as defined in the following claims; as interpreted by the description and drawings.

Claims

1. A method for adjusting lens comprising the following steps: a. providing a sensor-housing which containing an image sensor; b. providing a translation-carrier and placing the translation-carrier between lens group and the sensor-housing; c. according to the position offset of the image sensor and the lens group, horizontally moving the translationcarrier for eliminating horizontal offset of the lens, rotating the lens group I for eliminating the vertical incline of the axis of lens group to the center of the image sensor; and, d. fixing the sensor-housing, the translation-carrier and the lens group.

2. The method for adjusting lens as claimed in Claim 1, wherein the translation-carrier is placed on the sensor-housing and then the lens group is located on the translation-carrier.

3. The method for adjusting lens as claimed in Claim 1, wherein the lens group is located on the translation-carrier and then the translationcarrier is placed on the sensor-housing.

4. The method for adjusting lens as claimed in Claim 1, wherein the translation-carrier is horizontally moved and rotating the lens group is rotated f at the same time.

5. The method for adjusting lens as claimed in Claim 1, wherein the lens group is rotated and then the translation-carrier is horizontally moved.

6. The method for adjusting lens as claimed in Claim 1, wherein the translation-carrier is horizontally moved and then the lens group is rotated.

7. A mechanism for adjusting lens comprising a sensor-housing; an image sensor contained in the sensor-housing; a translation-carrier placed on the sensor-housing and a lens group at least including a first lens and a second lens engaged together and disposed on the translation-carrier the translation-carrier having an aperture formed in the central section thereof to allow the lens group disposed thereon.

8. A mechanism for adjusting lens as claimed in Claim 7, wherein the underside of the first lens is convex, and the underside enters into the aperture.

9. A mechanism for adjusting lens as claimed in Claim 7, wherein the translation-carrier further comprises a brim upwardly extending from edge of the aperture, so that the underside of the first lens covers with the brim when the underside of the first lens is concave.

10. A mechanism for adjusting lens as claimed in Claim 7, further comprising a drawtube which includes a cylinder and a underside portion to receive the lens group therein and allows the underside portion disposed on the translation-carrier.

11. A method for adjusting a lens substantially as any one herein described with reference to Figs 1 to 4 of the accompanying drawings.

12. A mechanism for adjusting a lens substantially as herein described with reference to and as illustrated in Fig I or Fig 2 or Fig 3 or Fig 4 of the accompanying drawings.