Zoom lens and image projection apparatus having the same

An image projection apparatus comprising:

• a zoom lens;
• a display unit for forming an original picture;
• wherein the original picture formed by the display unit is projected onto a projection surface by the zoom lens,
• wherein the zoom lens includes a plurality of lens units including a first lens unit disposed most adjacent to an enlargement side and having negative refractive power, at least one of said plurality of lens units is moved in the direction of the optical axis thereof during magnification change;
• and said first lens unit includes a 1-1st lens unit comprising at least one lens having negative refractive power and moved during focusing and a 1-2nd lens unit having positive refractive power and fixed during focusing.

A zoom lens comprising:

• a first lens unit disposed most adjacent to an enlargement side and having negative refractive power;
• a last lens unit disposed most adjacent to a reduction side and having positive refractive power;
• and
• one or more lens units moved in the direction of the optical axis thereof during zooming (magnification change);
• wherein a first lens in the first lens unit which is disposed most adjacent to the enlargement side has negative refractive power,
• the last lens in said last lens unit which is disposed most adjacent to the reduction side has positive refractive power, and the following condition is satisfied,
• 32<νdR−νdF,
• where νdF represents the Abbe number of the material of the first lens and νdR represents the Abbe number of the material of the last lens.

An image projection apparatus comprising:

• a zoom lens;
• and
• a display unit for forming an original picture;
• wherein the original picture formed by the display unit is projected onto a projection surface by the zoom lens,
• wherein the zoom lens includes a first lens unit disposed most adjacent to an enlargement side and having negative refractive power;
• a last lens unit disposed most adjacent to a reduction side and having positive refractive power;
• and one or more lens units moved in the direction of the optical axis thereof during zooming (magnification change);
• wherein a first lens in the first lens unit which is disposed most adjacent to the enlargement side has negative refractive power, the last lens in said last lens unit which is disposed most adjacent to the reduction side has positive refractive power, and the following condition is satisfied,
• 32<νdR−νdF,
• where νdF represents the Abbe number of the material of the first lens and νdR represents the Abbe number of the material of the last lens.