Imaging lens assembly

Patent metadata

Field	Value
Publication number	US-11835786-B2
Application number	US-202217705884-A
Country	US
Kind code	B2
Filing date	Mar 28, 2022
Priority date	Feb 7, 2017
Publication date	Dec 5, 2023
Grant date	Dec 5, 2023

Abstract

A multi-element imaging lens can be formed from five plastic elements, and an optional null-power or relatively low power sixth plastic element. The lens can use selected plastic materials to reduce a thermal focal shift. In the lens, negative refractive power elements can be formed from plastic materials having a relatively large negative refractive index variation with temperature, abbreviated as dn/dT, while positive refractive power elements can be formed from plastic materials having a relatively small negative dn/dT. Reducing the thermal focal shift, as disclosed, can eliminate the need for an auto-focusing device, such as a voice coil. Reducing the thermal focal shift, as disclosed, can also eliminate the need to use one or more glass elements to further reduce thermal focal shift, which can reduce cost for the lens.

First claim

What is claimed is:

1. An imaging lens assembly having a positive total refractive power, the imaging lens assembly comprising in order from an object side to an image side:
a first lens element being formed from a material having a dn/dT less than −99×10 −6 /° C.;
a second lens element with zero or positive refractive power between 0% and 5% of the total refractive power;
a third lens element being formed from a material having a dn/dT greater than −95×10 −6 /° C.;
a fourth lens element being formed from a material having a dn/dT less than −118×10 −6 /° C.;
a fifth lens element being formed from a material having a dn/dT greater than −95×10 −6 /° C.; and
a sixth lens element being formed from a material having a dn/dT less than −118×10 −6 /° C.

2. The imaging lens assembly of claim 1 , wherein the first, second, third, fourth, fifth, and sixth elements are formed from plastic.

3. The imaging lens assembly of claim 1 , wherein the first, second, third, fourth, fifth, and sixth elements are mounted in a plastic barrel and are spaced apart by plastic spacers.

4. The imaging lens assembly of claim 1 , wherein:
the first lens element is formed from a material having an Abbe number greater than 50;
the second lens element is formed from a material having an Abbe number less than 35;
the third lens element is formed from a material having an Abbe number greater than 50;
the fourth lens element is formed from a material having an Abbe number less than 27;
the fifth lens element is formed from a material having an Abbe number greater than 50; and
the sixth lens element is formed from a material having an Abbe number less than 27.

5. A mobile device, comprising a processor and memory, the memory including instructions that, when executed by the processor, cause the processor to store a digital image generated by the imaging lens assembly of claim 1 .

6. The imaging lens assembly of claim 1 , further comprising a blue glass absorptive filter positioned between the sixth lens element and an image plane.

7. A method of manufacturing an imaging lens assembly, the method comprising:
combining a plurality of lens elements into an imaging lens assembly, the plurality of lens elements comprising:
a first lens element being formed from a material having a dn/dT less than −99×10 −6 /° C.;
a second lens element with zero or positive refractive power between 0% and 5% of a total refractive power;
a third lens element being formed from a material having a dn/dT greater than −95×10 −6 /° C.;
a fourth lens element being formed from a material having a dn/dT less than −118×10 −6 /° C.;
a fifth lens element being formed from a material having a dn/dT greater than −95×10 −6 /° C.; and
a sixth lens element being formed from a material having a dn/dT less than −118×10 −6 /° C.

8. The method of claim 7 , wherein the first, second, third, fourth, fifth, and sixth elements are formed from plastic.

9. The method of claim 7 , wherein the first, second, third, fourth, fifth, and sixth elements are mounted in a plastic barrel and are spaced apart by plastic spacers.

10. The method of claim 7 , wherein:
the first lens element is formed from a material having an Abbe number greater than 50;
the second lens element is formed from a material having an Abbe number less than 35;
the third lens element is formed from a material having an Abbe number greater than 50;
the fourth lens element is formed from a material having an Abbe number less than 27;
the fifth lens element is formed from a material having an Abbe number greater than 50; and
the sixth lens element is formed from a material having an Abbe number less than 27.

11. The method of claim 7 , further comprising placing a blue glass absorptive filter between the sixth lens element and an image plane.

Assignees

• Snap Inc

Inventors

• Bates Robert Matthew

Classifications

• G02B7/028 Primary

  with means for compensating for changes in temperature or for controlling the temperature; thermal stabilisation · CPC title

• G02B1/041

  Lenses · CPC title

• G02B5/226

  Glass filters · CPC title

• G02B7/021

  for more than one lens · CPC title

• G02B9/62

  having six components only · CPC title