The present invention relates to a photographic film package in which a photographic film, a taking lens and an exposure member, with their associated elements, are incorporated in a light-tight film casing as a unit.
A lens-fitted photographic film package can provide many opportunities for enjoyment by readily taking pictures even with no camera. This lens-fitted photographic film package comprises a light-tight film casing fitted with a taking lens, a simple exposure mechanism with includes a film winding mechanism and a shutter mechanism with their associated elements incorporated in the film casing, and a 110-size cartridge film previously packaged in the film casing, which can be sold wherever photographic film is sold. The lens-fitted photographic film, after the exposure of all frames of the film, is forwarded to a photo shop or photo laboratory without removing the film. There, the film package is opened and the exposed film is developed to make prints therefrom while the film package without the film is scrapped. The prints, together with the developed film, are returned to the customer. Such a lens-fitted single-use film package makes it easy to take pictures because there is no need for film loading and unloading.
As is well known in the art, a 110-size film cartridge contains therein a roll of 110-size film which has a sensitivity (ISO 100) sufficient to form an image with a satisfactory image quality within a certain range of brightness by using a taking lens having a focal length f of 26 mm and an F-number of 11 at a shutter speed of 1/100 sec. However, it is hard to make an enlarged print with a favorable image quality from the 110-size film. For better image quality, it has been proposed to provide a lens-fitted film package including a 135-size roll film whose image size is 36.times.24 mm. By incorporating the 135-size roll film contained in a film patrone defined by the International Organization for Standardization (ISO code 1007: 1979 Edition) in such a lens-fitted film package, the existing film manufacturing processes, film processing systems, printing systems can be utilized in their entireties for the lens-fitted film packages.
It is absolutely required, for such 135-size film packages, not only that they be simple and compact in construction but also that they be cheap. The film package containing a 135-size film needs a taking lens having a focal length of approximately 45 to 55 mm in order to form a normally magnified image in an image frame (24.times.36 mm) of the film; the provision of such a taking lens having a relatively long focal length results in making the film package bulky, in particular thick.
In order to make the film package thinner, it has hitherto been well known to those skilled in the art to provide a retractable taking lens. However, the provision of such a retractable taking lens needs to incorporate a retracting mechanism, resulting in an expensive film package.
Alternatively, one can utilize a standard taking lens having a focal length of approximately 55 mm which is used in the conventional 35 mm-size lens shutter type compact camera. However, such a standard taking lens has a plurality of lens components which includes some components having a large diameter, resulting in an expensive and bulky film package.
Another requirement for the film package is that it be simple in construction and hence low in manufacturing cost and cost of assembling. For this reason, the film package is divided into two or three unit blocks which are formed of plastic materials, namely a main body section, a front cover section and a rear cover section. Necessary elements including optical elements for a taking lens and a finder and mechanisms for exposure and film advance, with their associated elements, are incorporated in the main body section before assembling the three unit blocks.
For fitting such necessary elements made individually into the main body section, a delicate fitting operation which usually takes time is required. Therefore, it has been attempted not only to reduce the number of components of the film package but also to provide the necessary components which make assembling operations simple so as to provide a cheap film package.