초록 ▼

A microfilm image reader apparatus for detecting an image on a microfilm strip and projecting the detected image onto a target plane, wherein a beam of light bearing an image detected from the microfilm strip is produced by illuminating the microfilm strip and is projected through a projection lens

A microfilm image reader apparatus for detecting an image on a microfilm strip and projecting the detected image onto a target plane, wherein a beam of light bearing an image detected from the microfilm strip is produced by illuminating the microfilm strip and is projected through a projection lens onto the target plane, and wherein an automatic mode of focus control is established through detection of a condition in which the image-bearing beam is focussed with respect to the target plane and, when it is detected that the automatic mode of focus control is inoperable, the projection lens is automatically moved to a position having its focal plane located on a predetermined plane with respect to the target plane and, after the projection lens is moved to such a position, the focal plane of the projection lens may be manually adjusted by the operator of the apparatus.

대표청구항 ▼

A microfilm image reader for projecting an image of a microfilm onto a target plane, comprising: means for illuminating the microfilm for producing an image-bearing beam of light bearing the image of the microfilm; a projection lens for projecting said image-bearing beam of light onto said target pl

A microfilm image reader for projecting an image of a microfilm onto a target plane, comprising: means for illuminating the microfilm for producing an image-bearing beam of light bearing the image of the microfilm; a projection lens for projecting said image-bearing beam of light onto said target plane; first detecting means for detecting a condition in which said image-bearing beam of light is focused with respect to said target plane; first focus control means responsive to the condition detected by said detecting means and operative to establish an automatic mode of focus control operation for automatically moving said projection lens to adjust the focal plane of the lens with respect to said target plane depending on the condition detected by said detecting means; second detecting means for detecting a condition in which the automatic mode of focus control is inoperable; second focus control means responsive to the condition detected by said second detecting means and operative to automatically move said projection lens to a position having its focal plane located on a predetermined plane with respect to said target plane when it is detected by said second detecting means that the automatic mode of focus control is inoperable; manual focus control means for permitting manual adjustment of the focal plane of said projection lens after the projection lens is moved to said position by said second automatic focus control means; and indicating means for indicating the direction in which said projection lens should be moved with respect to said target plane by said manual focus control means when said projection lens is moved to said position by said second focus control means.