Many aspects of the present method 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 method. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views.
Corresponding reference characters indicate corresponding parts throughout the drawings. The exemplifications set out herein illustrate at least one preferred embodiment of the present method, in one form, and such exemplifications are not to be construed as limiting the scope of the invention in any manner.
References will now be made to the drawings to describe preferred embodiments of the present method, in detail.
Referring to
In step (1), a wavelength of the laser beam 24 emitted from the IR laser device 20 is about 794 nanometers. The IR-cut filter 10 is arranged between the IR laser device 20 and the IR laser sensor 22, and the IR laser device 20 and the IR laser sensor 22 are aligned with each other.
The IR-cut filter 10 includes a substrate 12 and an IR-cut filter film 14. The IR-cut filter film 14 is attached on a surface of the substrate 12. A material of the substrate 12 is selected from the group consisting of glass, gelatin, and plastic, preferably glass. The IR-cut filter film 14 reflects IR light so as to avoid the IR light entering into the image sensor of an image pick-up device. Therefore, quality of resulting image is enhanced.
In step (2), a width L of the laser beam 24 is satisfied by the following equation: L=D×sin θ, wherein D represents a thickness of the substrate 12. The incident angle θ is an acute angle. In this preferred embodiment, the incident angle θ is about 45 degrees. Therefore, the width L of the laser beam is equal to D/√{square root over (2)}. The IR laser beam 24 is obliquely incident on an edge portion of the IR-cut filter 10, as shown in
In step (3), since the IR laser beam 24 is obliquely incident on the edge portion of the IR-cut filter 10, a light intensity of the laser beam 24 received by the IR sensor 22 is different if a location of the filter film 14 is on a surface of the substrate 12 facing towards the IR laser device 20 or facing towards the IR sensor 22.
Referring to
in step (4), a set of the determined IR-cut filters 10 are arranged on a supporting table (not shown) in a manner that the oriented direction of the location of the filter film 14 on the substrate 12 are identical. Therefore, in the process of assembling the IR-cut filter to a lens module, the oriented directions of the location of the filter film 14 on the substrate 12 of the IR-cut filters 10 are kept identical to make sure of the optical consistency of each lens module. The direction of orientation of the location of filter film 14 on the substrate 12 of the IR-cut filter 10 may face an object side or an image side of the lens module.
Referring to
The IR sensor 22 receives the IR laser beam 24 reflected by the surface of the IR-cut filter 10. If the light intensity of the IR laser beam 24 received by the IR sensor 22 is the same as or close to a light intensity of the IR laser beam 24 emitted from the IR laser device 20, the location of the filter film 14 is on a surface of the substrate 12 facing towards the IR laser device 20. If the light intensity of the IR laser beam 24 received by the IR sensor 22 is equal to or close to zero, the location of the filter film 14 is on a surface of the substrate 12 away from the IR laser device 20. Accordingly, the location of the filter film 14 on the substrate 12 may be determined.
It is to be understood that the above-described embodiment is intended to illustrate rather than limit the invention. Variations may be made to the embodiment without departing from the spirit of the invention as claimed. The above-described embodiments are intended to illustrate the scope of the invention and not restrict the scope of the invention.
Number | Date | Country | Kind |
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200610060629.0 | May 2006 | CN | national |