IMAGING LENS UNIT

• US 20110038065A1
• Filed: 04/16/2009
• Published: 02/17/2011
• Est. Priority Date: 04/16/2008
• Status: Active Grant

• Current Assignee: Komatsulite Mfg Co., Ltd. (Bourns Incorporated), Nippon Shokubai Company Limited
• Original Assignee: Komatsulite Mfg Co., Ltd. (Bourns Incorporated), Nippon Shokubai Company Limited
• Inventors: Kasano, Yukihiro, Tsujino, Yasunori, Miyawaki, Yoshihiro, Nakamura, Junichi, Muraoka, Yuji, Yamashita, Masafumi, Ando, Nobuyuki
• Granted Patent: US 8,270,103 B2
• Time in Patent Office: Days
• US Class Current: 359/819
• CPC Class Codes: G02B 13/0035 having three lenses
• CPC Class Codes: G02B 13/006 at least one element being a compound optical element, e.g. cemented elements
• CPC Class Codes: G02B 7/021 for more than one lens
• CPC Class Codes: G02B 7/022 lens and mount having complementary engagement means, e.g. screw/thread

Abstract

The present invention provides an imaging lens unit configured to be processed by the solder reflow process, can be miniaturized, and has sufficient thermal resistance for the reflow temperatures. The imaging lens unit also provides excellent optical characteristics such as transmissivity, a refractive index, and the like without deteriorating the optical characteristics in alignment of the centers of the lens and the diaphragm even after the reflow process, so as to contribute to reduction in the size and an increase in the capabilities. The imaging lens unit is configured to be processed by a solder reflow process, and includes a lens group consisting of one or more lenses; and a lens tube that supports the lens group, wherein the imaging lens unit comprises one or more cationically-cured epoxy resin lenses formed from an cationically-curable epoxy resin material, the lens tube is formed from a thermoplastic resin material having a deflection temperature under load of not lower than 200° C., and the imaging lens unit has a clearance between the lens tube and at least one of the cationically-cured epoxy resin lenses and has lens supporting portions that are provided at at least three locations inside the lens tube and that support the at least one cationically-cured epoxy resin lens.

Claims

1. An imaging lens unit configured to be processed by a solder reflow process, comprising:

a lens group consisting of one or more lenses; and

a lens tube that supports the lens group,

wherein

the imaging lens unit comprises one or more cationically-cured epoxy resin lenses formed from a cationically-curable epoxy resin material,

the lens tube is formed from a thermoplastic resin material having a deflection temperature under load of not lower than 200°

C., and

the imaging lens unit has a clearance between the lens tube and at least one of the cationically-cured epoxy resin lenses and has lens supporting portions that are provided at at least three locations inside the lens tube and that support the at least one cationically-cured epoxy resin lens.

2. The imaging lens unit according to claim 1,

wherein the imaging lens unit has a clearance between the lens tube and the cationically-cured epoxy resin lens supported by the lens supporting portions, in a manner that satisfies the following formula (1):

{L×

(T−

25)×

α

²−

B−

(T−

25)×

α

¹}×

(½

)≦

X  

 

(1)

wherein B represents an inner diameter of the lens tube at an installation place of the cationically-cured epoxy resin lens at 25°

C.;

L represents a diameter of the cationically-cured epoxy resin lens at 25°

C.;

α

¹ represents an average thermal expansion coefficient of the lens tube in a temperature range of from 25°

C. to 260°

C.;

α

² represents an average thermal expansion coefficient of the cationically-cured epoxy resin lens in the temperature range of from 25°

C. to 260°

C.;

T represents the highest temperature (°

C.) in the solder reflow process for the imaging lens unit; and

X represents the clearance.

3. The imaging lens unit according to claim 2,

wherein the average thermal expansion coefficients of the lens tube formed from the thermoplastic resin material and the cationically-cured epoxy resin lens have a value of α

¹/α

² in the range of 0.01 to 1.

4. The imaging lens unit according to claim 1,

wherein the lens supporting portion supports the lens in a manner to bite into the lens.

5. The imaging lens unit according to claim 1,

wherein the imaging lens unit has a depression on the lens supported by the lens supporting portions, at contact portions in contact with the lens supporting portions.

6. The imaging lens unit according to claim 1,

wherein the lens is configured to be received within the lens tube that has the lens supporting portions provided therein.

7. The imaging lens unit according to claim 1,

wherein the thermoplastic resin material is an organic-inorganic composite that contains an inorganic fiber as an inorganic component.

8. The imaging lens unit according to claim 1,

wherein the lens group consists of multiple cationically-cured epoxy resin lenses,

at least one of the multiple cationically-cured epoxy resin lenses is supported by the lens support portions, and

the other cationically-cured epoxy resin lenses are supported by being fitted with the lens supported by the lens supporting portions and/or with the lens tube.

9. The imaging lens unit according to claim 1,

wherein the cationically-cured epoxy resin lens other than the one or more cationically-cured epoxy resin lenses supported by the lens supporting portions has a tapered portion, and is supported by being fitted with the lens supported by the lens supporting portions and/or with the lens tube.

10. The imaging lens unit according to claim 1,

wherein the lens group consists of multiple cationically-cured epoxy resin lenses, and a difference among the average thermal expansion coefficients of the cationically-cured epoxy resin lenses is not higher than 50 ppm/°

C.

11. The imaging lens unit according to claim 1,

wherein the lens group consisting of the one or more lenses has an Abbe'"'"'s number ν

d that satisfies the following formula (2);

31≦

d≦

62.  

 

(2)

12. The imaging lens unit according to claim 1,

wherein the imaging lens unit has a circular hollow light-shielding plate, being not more than 0.5 mm in thickness, between at least two lenses among the multiple lenses constituting the lens group.

13. The imaging lens unit according to claim 1,

wherein the imaging lens unit is produced through the solder reflow process.

14. The imaging lens unit according to claim 13,

wherein the imaging lens unit is mounted on a camera module when being processed by the solder reflow process, and is intended to be used for a camera module.

15. A method of producing an imaging lens unit, including a process of producing the imaging lens unit according to claim 1.

16. The imaging lens unit according to claim 2,

wherein the lens supporting portion supports the lens in a manner to bite into the lens.

17. The imaging lens unit according to claim 3,

wherein the lens supporting portion supports the lens in a manner to bite into the lens.

18. The imaging lens unit according to claim 2,

wherein the imaging lens unit has a depression on the lens supported by the lens supporting portions, at contact portions in contact with the lens supporting portions.

19. The imaging lens unit according to claim 3,

wherein the imaging lens unit has a depression on the lens supported by the lens supporting portions, at contact portions in contact with the lens supporting portions.

20. The imaging lens unit according to claim 4,

wherein the imaging lens unit has a depression on the lens supported by the lens supporting portions, at contact portions in contact with the lens supporting portions.