| 发明名称 |
IMAGE READING LENS, IMAGE READING DEVICE, AND IMAGE FORMING DEVICE |
| 摘要 |
An image reading lens includes a front lens group of five lenses including a positive lens and a negative lens, disposed on an object side and a rear lens group disposed on an image side, including a negative plastic lens. The image reading lens satisfies the following conditions:;0<ΣdnN/dt(N)−Σdnp/dt(P)<25;0.10<fa/f×d11/D<0.90;−1.5<fb/f<−0.5;0.35<d11/D<0.70;where ΣdnN/dt(N) and Σdnp/dt(P) are sums of 106-fold temperature coefficients of refractive indexes of the negative and positive lenses of the front lens group along a He—Ne line at a temperature of 40 to 60° C., respectively, fa, fb, and f are focal lengths of the front lens group, rear lens group, and image reading lens, respectively, d11 is an on-axis distance between the front and rear lens groups, and D is the total length of the image reading lens. |
| 申请公布号 |
US2015212319(A1) |
申请公布日期 |
2015.07.30 |
| 申请号 |
US201514597657 |
申请日期 |
2015.01.15 |
| 申请人 |
NAGANO Takuya |
发明人 |
NAGANO Takuya |
| 分类号 |
G02B27/00;G02B13/18;G02B9/34;H04N1/028;H04N1/193 |
主分类号 |
G02B27/00 |
| 代理机构 |
|
代理人 |
|
| 主权项 |
1. An image reading lens, comprising:
a front lens group disposed on an object side, comprising first to fifth lenses including a positive lens and a negative lens; and a rear lens group disposed on an image side, comprising a negative plastic lens, wherein the image reading lens has an angle of view of 56 degrees or more the image reading lens is formed to satisfy the following four conditions:
0<ΣdnN/dt(N)−Σdnp/dt(P)<25 (1)0.10<fa/f×d11/D<0.90 (2)−1.5<fb/f<−0.5 (3)0.35<d11/D<0.70 (4) where ΣdnN/dt(N) and Σdnp/dt(P) are sums of 106-fold temperature coefficients of refractive indexes of the negative and positive lenses of the front lens group along a He—Ne line at a temperature of 40 to 60° C., respectively, fa is a focal length of the front lens group, fb is a focal length of the rear lens group, f is a focal length of the entire image reading lens, d11 is an on-axis distance between the front lens group and the rear lens group, and D is the total length of the image reading lens. |
| 地址 |
Kanagawa JP |
