JP2004199092A5 - - Google Patents

Description

In order to achieve the above object, a feature of the imaging lens according to claim 1 of the present invention is an imaging lens used to form an image of an object on an imaging surface of a solid-state imaging device,
In order from the object side to the image surface side, the first resin lens made of a meniscus lens having a positive power with the convex surface facing the object side, the diaphragm, and the positive power with the convex surface facing the image surface A second lens made of resin, which is a meniscus lens having the lens, is disposed, and the following conditional expressions (1) to (6) are provided:
1.17 x fl L L 1.0 1.07 x fl (1)
1.26 × fl ≧ f ₁ ≧ 0.85 × fl (2)
0.8 × d ₁ dd ₂ > 0.5 × d ₁ (3)
L ≦ 6.25 mm (4)
d ₁ 0.20.225 × fl (5)
d ₃ 0.2 0.225 × fl (6)
However,
L: Total length of lens system (distance from the object side surface of the first lens to the imaging surface (air equivalent length))
fl: focal length of the whole lens system f ₁ : focal length of the first lens d ₁ : center thickness of the first lens d ₂ : distance between the first lens and the second lens on the optical axis d ₃ : of the second lens The point is to satisfy the center thickness.

According to the invention of claim 1, by satisfying the conditional expressions (1) and (2), the entire optical system can be reduced in size and weight, and the exit pupil and the imaging surface ( By maintaining the distance between the sensor and the sensor to improve telecentricity, it is possible to make effective use of light rays incident on the sensor end. Furthermore, coma and distortion can be corrected effectively to improve the optical performance, and manufacturability can be improved. Furthermore, by satisfying the conditional expression (3), it is possible to more effectively ensure manufacturability and to maintain high optical performance. Furthermore, by satisfying the conditional expression (4), it is possible to realize further downsizing of the entire optical system. Further, by making the first and second lenses be lenses made of resin and defining the center thickness of each lens (conditions (5) and (6)), the manufacturability of the lenses is further improved. It becomes possible to provide an inexpensive lens. Furthermore, by forming the second lens as a meniscus lens having positive power, it is possible to more effectively ensure telecentricity.

Further, in the imaging lens system according to claim 2, in claim 1, wherein the diaphragm is a line on the optical axis connecting the object side surface of said the image plane side surface of the first lens the second lens It is located at a position closer to the first lens than the midpoint of the minute.

According to the second aspect of the present invention, the stop is more than the midpoint of the line segment on the optical axis connecting the surface on the image plane side of the first lens and the surface on the object side of the second lens. Since the lens is disposed on the side of the first lens, the distance between the exit pupil and the imaging surface (sensor) can be more reliably maintained, and no load is imposed on the shape or the like of each lens. It will be possible to secure telecentricity.

The feature of the imaging lens according to claim 3 is that in claim 1 or 2 , the brightness of the optical system is defined as follows.
4.0> Fno (7)
However, Fno: Brightness of the optical system

Then, according to the invention of claim 3 , it is possible to exhibit better optical performance under a situation where the light quantity such as night time or dark place required for the imaging device equipped with the imaging lens according to the present invention is small. It becomes possible.

The feature of the imaging lens according to claim 4 is that, in any one of claims 1 to 3 , the diagonal angle of view is defined as follows.
2ω ≧ 50 ° (8)
However, 2ω: diagonal angle of view

Then, according to the invention of claim 4 , it is possible to sufficiently satisfy the requirement for wide angle of view required for the imaging device on which the imaging lens according to the present invention is mounted.

In the imaging lens according to a fifth aspect of the present invention, in the imaging lens according to any one of the first to fourth aspects, the following conditional expression (9):
fl ≦ 5.0 mm (9)
To be satisfied.

And according to the invention concerning this Claim 5 , in order to realize an imaging lens miniaturized while maintaining a wide angle of field, it becomes possible to make a more suitable composition.

According to the imaging lens which concerns on Claim 1 of this invention, the imaging lens small in size and excellent in manufacturability is realizable, maintaining favorable optical performance. Furthermore, a compact imaging lens that is excellent in optical performance and that can effectively utilize the amount of light incident on the solid-state imaging device can be realized.

Further, with the imaging lens according to claim 2, may be claimed in addition to the effects of the imaging lens according to claim 1, implementing effectively available compact imaging lens the amount of light further enters the solid-state imaging device .

Moreover, according to the imaging lens which concerns on Claim 3 , in addition to the effect of the imaging lens which concerns on Claim 1 or 2 , exhibiting the further outstanding optical performance under the condition with few light quantities, such as night time or a dark place Can be realized.

According to the imaging lens of claim 4 , in addition to the effects of the imaging lens of claims 1 to 3 , an imaging lens with a wide angle of view capable of photographing a wide range of scenery and a large number of people is realized. can do.

Moreover, according to the imaging lens which concerns on Claim 5 , in addition to the effect of the imaging lens which concerns on Claims 1-4 , it can implement | achieve the imaging lens which miniaturized the full length, maintaining wide angle of view further. .

Claims (5)

An imaging lens used to form an image of an object on an imaging surface of a solid-state imaging device, the imaging lens comprising:
In order from the object side to the image surface side, the first resin lens made of a meniscus lens having a positive power with the convex surface facing the object side, the diaphragm, and the positive power with the convex surface facing the image surface A second lens made of resin, which is a meniscus lens having the lens, is disposed, and the following conditional expressions (1) to (6) are provided:
1.17 x fl L L 1.0 1.07 x fl (1)
1.26 × fl ≧ f ₁ ≧ 0.85 × fl (2)
0.8 × d ₁ dd ₂ > 0.5 × d ₁ (3)
L ≦ 6.25 mm (4)
d ₁ 0.20.225 × fl (5)
d ₃ 0.2 0.225 × fl (6)
However,
L: Total length of lens system (distance from the object side surface of the first lens to the imaging surface (air equivalent length))
fl: focal length of the whole lens system f ₁ : focal length of the first lens d ₁ : center thickness of the first lens d ₂ : distance between the first lens and the second lens on the optical axis d ₃ : of the second lens An imaging lens characterized by satisfying a center thickness. The diaphragm is disposed on the first lens side with respect to a midpoint of a line segment on an optical axis connecting a surface on the image plane side of the first lens and a surface on the object side of the second lens. the imaging lens according to claim 1, characterized in that it is. The imaging lens according to claim 1 or 2, characterized in that the brightness of the optical system is defined as follows.
4.0> Fno (7)
However, Fno: Brightness of the optical system The imaging lens according to any one of claims 1 to 3, wherein a diagonal angle of view is defined as follows.
2ω ≧ 50 ° (8)
However, 2ω: diagonal angle of view Furthermore, the following conditional expression (9),
fl ≦ 5.0 mm (9)
The imaging lens according to any one of claims 1 to 4 , wherein