LENS MODULE AND CAMERA EMPLOYING THE SAME

• US 20070285555A1
• Filed: 11/03/2006
• Published: 12/13/2007
• Est. Priority Date: 06/09/2006
• Status: Active Grant

• Current Assignee: Hon Hai Precision Industry Co., Ltd.
• Original Assignee: Hon Hai Precision Industry Co., Ltd.
• Inventors: CHEN, GA-LANE
• Granted Patent: US 7,663,686 B2
• Time in Patent Office: Days
• US Class Current: 348/340
• CPC Class Codes: G02B 5/208 for use with infrared or ultraviolet radiation, e.g. for separating visible light from infrared and/or ultraviolet radiation
• CPC Class Codes: G02B 7/021 for more than one lens
• CPC Class Codes: H04N 23/54 Mounting of pick-up tubes, electronic image sensors, deviation or focusing coils
• CPC Class Codes: H04N 23/57 Mechanical or electrical details of cameras or camera modules specially adapted for being embedded in other devices

Abstract

A lens module includes a barrel defining a through hole, at least one plastic lens accommodated in the through hole and a UV/IR cut filter mounted on the barrel and configured for preventing entry of both UV light and IR light into the barrel. The lens module has a UV/IR cut filter mounted on the barrel configured for preventing entry of both UV light and IR light into the barrel, so it can prevent UV light damaging plastic lenses, and accordingly can improve the useful life of the lens module.

Claims

1. A lens module, comprising:

a barrel defining a through hole;

at least one plastic lens accommodated in the through hole, and

a UV/IR cut filter mounted on the barrel and configured for preventing entry of both UV light and IR light into the barrel.

2. The lens module as claimed in claim 1, wherein the barrel has a focus adjusting ring arranged at one end thereof with the UV/IR cut filter mounted thereon.

3. The lens module as claimed in claim 2, wherein the focus adjusting ring is integrally formed with the barrel.

4. The lens module as claimed in claim 1, wherein the lens module comprises a first lens and a second lens, the first lens having a peripheral annular wall surrounding the second lens therein.

5. The lens module as claimed in claim 4, further comprising at least one spacer arranged between the first lens and the second lens.

6. The lens module as claimed in claim 1, wherein the UV/IR cut filter comprises a transparent substrate having a first surface and an opposite second surface, a UV/IR cut filter film formed on the first surface, and an anti-reflection coating formed on the second surface.

7. The lens module as claimed in claim 6, wherein the second surface of the transparent substrate faces the at least one plastic lens.

8. The lens module as claimed in claim 6, wherein the UV/IR cut filter film is a film stack, the film stack comprising a plurality of high refractive index layers and a plurality of low refractive index layers alternately stacked one on another, wherein the film stack is represented as follows:

(3.5H3.5L)⁷(2.5H2.5L)⁷(HL)⁶(0.76H0.76L)⁶

wherein H represents a high refractive index layer having a base optical thickness equal to one fourth of a reference wavelength associated with the filter, L represents a low refractive index layer having a base optical thickness equal to one fourth of a reference wavelength associated with the filter, the expression enclosed in each parenthesis represents a filter cavity, and the superscript represents the number of repetitions of the expression enclosed in that parenthesis.

9. The lens module as claimed in claim 8, wherein the high refractive index material is selected from a group consisting of Ti₃O₅, TiO₃, TiO₂, Ta₂O₅, and any mixtures thereof.

10. The lens module as claimed in claim 8, wherein the low refractive index material is selected from a group consisting of SiO₂, Al₂O₃, AlN, and any mixtures thereof.

11. A camera, comprising:

a lens module comprising;

a barrel defining a through hole;

at least one plastic lens accommodated in the through hole, and

a UV/IR cut filter mounted on the barrel and configured for preventing entry of both UV light and IR light into the barrel; and

an imaging module coupled to the lens module, the imaging module comprising

a holder; and

an image sensor received in the holder.

12. The camera as claimed in claim 11, wherein the barrel is threadedly engaged with the holder.

13. The camera as claimed in claim 11, wherein the image sensor is a charge coupled device (CCD) or a complementary metal oxide semiconductors (CMOS).

14. The camera as claimed in claim 11, wherein the barrel has a focus adjusting ring arranged at one end thereof with the UV/IR cut filter mounted thereon.

15. The camera as claimed in claim 14, wherein the focus adjusting ring is integrally formed with the barrel.

16. The camera as claimed in claim 11, wherein the lens module comprises a first lens and a second lens, the first lens having a peripheral annular wall surrounding the second lens therein.

17. The camera as claimed in claim 16, further comprising at least one spacer arranged between the first lens and the second lens.

18. The camera as claimed in claim 11, wherein the UV/IR cut filter comprises a transparent substrate having a first surface and an opposite second surface, a UV/IR cut filter film formed on the first surface, and an anti-reflection coating formed on the second surface.

19. The camera as claimed in claim 19, wherein the UV/IR cut filter film is a film stack, the film stack comprising a plurality of high refractive index layers and a plurality of low refractive index layers alternately stacked one on another, wherein the film stack is represented as follows:

(3.5H3.5L)⁷(2.5H2.5L)⁷(HL)⁶(0.76H0.76L)⁶

wherein H represents a high refractive index layer having a base optical thickness equal to one fourth of a reference wavelength associated with the filter, L represents a low refractive index layer having a base optical thickness equal to one fourth of a reference wavelength associated with the filter, the expression enclosed in each parenthesis represents a filter cavity, and the superscript represents the number of repetitions of the expression enclosed in that parenthesis.