Abstract:
A film scanner includes a light source, an illumination optical system which illuminates a film surface of a film with a light bundle emitted from the light source after the light bundle is varied in accordance with a film size of the film, and an image pickup optical system which makes the light bundle transmitted through the film surface incident upon an image pickup element after the light bundle is varied in accordance with the size of an effective area of the image pickup element.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The present invention relates to a film scanner in which an image recorded on an exposed silver halide film is picked up and converted into digital image data.  
           [0003]    2. Description of the Related Art  
           [0004]    In general, a film scanner in which an image recorded on an exposed silver halide film is scanned to produce digital image data includes a light source, an image pickup element, an illuminating optical system which transmits light emitted from the light source to a film, and an image pickup optical system which transmits the light transmitted through the film to the image pickup element.  
           [0005]    In many film scanners, films of different sizes (i.e., different widths of film strip), such as a 35 mm film or a Brownie film (a strip of film having a width of 60 mm), can be scanned. However, in conventional film scanners, the illumination optical system and image pickup optical system are provided so that the image on the film having the largest width matches with the area of the image pickup element.  
           [0006]    To solve this problem, the image pickup optical system can be constructed as a optical system in which the focal length can be switched, so that the image pickup element does not have a non-utilized area when a narrow film is scanned. However, if the image pickup optical system is constructed from a optical system in which the focal length can be switched, the amount of light which can be received by the image pickup element is remarkably reduced when the small width film is scanned, thus resulting in a dark image compared to when a large width film is scanned.  
           [0007]    Moreover, in conventional film scanners, a fluorescent lamp is used as the light source. Accordingly, it is difficult to synchronize the picking up of the image by the image pickup element with the emission of light by the fluorescent lamp. If synchronization fails, the picking-up of image is carried out with an insufficient amount of light. Furthermore, there is a drawback that the fluorescent lamp has large power consumption.  
         SUMMARY OF THE INVENTION  
         [0008]    The present invention provides a film scanner in which an image pickup optical system has a zooming function to make it possible to pick up images of films of different sizes at the same size, and the amount of light which can be received by the image pickup element is not reduced if the zooming operation of the image pickup optical system is carried out.  
           [0009]    According to an aspect of the present invention, a film scanner is provided, including a light source, an illumination optical system which illuminates a film surface of a film with a light bundle emitted from the light source after the light bundle is varied in accordance with a film size of the film, and an image pickup optical system which makes the light bundle transmitted through the film surface incident upon an image pickup element after the light bundle is varied in accordance with the size of an effective area of the image pickup element.  
           [0010]    It is desirable for the image pickup optical system to have a plurality of image pickup optical systems having different focal lengths, the plurality of image pickup optical system being selectively used.  
           [0011]    It is desirable for the film scanner to include an image pickup optical system selection mechanism for selecting the plurality of image pickup optical systems, a power varying mechanism for varying the optical power of the illumination optical system, and a single drive mechanism for driving the image pickup optical system selection mechanism and the power varying mechanism.  
           [0012]    The light source can be an LED.  
           [0013]    The present disclosure relates to subject matter contained in Japanese Patent Application No. 2002-248752 (filed on Aug. 28, 2002) which is expressly incorporated herein by reference in its entirety. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0014]    The invention will be discussed below with reference to the accompanying drawings, in which;  
         [0015]    [0015]FIG. 1 is a longitudinal sectional view of a film scanner which scans a Brownie film, according to an embodiment of the present invention;  
         [0016]    [0016]FIG. 2 is a plan view of an internal structure of the film scanner when a Brownie film is scanned;  
         [0017]    [0017]FIG. 3 is a plan view of an image pickup optical system when a Brownie film is scanned;  
         [0018]    [0018]FIG. 4 is a sectional view of a drive mechanism of the image pickup optical system and an illumination optical system;  
         [0019]    [0019]FIG. 5 is a side elevational view of main components of the film scanner which scans a 35 mm film; and  
         [0020]    [0020]FIG. 6 is a plan view of an internal structure of the film scanner when a 35 mm film is scanned. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0021]    An embodiment of the present invention will be discussed with reference to the drawings. As shown in FIG. 1, a film scanner  1  includes a casing  3  in the form of a laterally extending rectangular parallelepiped in which a light source made of a white LED  5 , an illumination optical system  7 , a pair of upper and lower mirrors M 1 , M 2 , an image pickup optical system  27 , an RGB 3-line linear CCD (image pickup element)  37  which will be referred to hereinafter as a linear CCD, a drive mechanism of the illumination optical system  7  and the image pickup optical system  27 , and a motor M as a drive source of the drive mechanism are arranged. The rotating shaft  15 , the gear  17 , the rotation transmission shaft  19 , the gears  21 ,  23 , the gear  25 , the upper gear train G 1 , the lower gear train G 2 , the motor M, and the pinion P thereof constitute the drive mechanism.  
         [0022]    The casing  3  is provided, on the front surface thereof, with a film insertion opening (not shown) and a slot (not shown) for a memory card. In the vicinity of the film insertion opening and the memory card slot, ejector buttons (not shown) are provided to eject a film F 1  or F 2  and a memory card (not shown), inserted in the film insertion opening and the memory card slot, respectively. A Brownie film F 1  and a 35 mm film F 2  can be selectively inserted in the film insertion opening. In the casing  3 , a film discrimination sensor (not shown) which discriminates the films F 1  and F 2 , and a film feeder (not shown) which moves the film F 1  or F 2  in the right hand direction in FIG. 1 intermittently by a displacement corresponding to a line pitch of the linear CCD  37  are arranged. The film discrimination sensor and the film feeder are connected to a CPU (not shown).  
         [0023]    The white LED  5  is located in the casing  3  at the upper corner thereof and emits light from the front surface of the LED. The illumination optical system  7  which receives the light emitted from the white LED  5  is made of a plurality of lenses. As can be seen in FIGS. 2 and 6, a pair of guide rails  9  are provided on opposite sides of the illumination optical system  7  and extend in a direction parallel with the optical axis O 1  of the illumination optical system  7 . A lens holder  11  is slidably fitted in the guide rails  9 . The lens holder  11  holds a movable lens  7   a  of the illumination optical system  7 . The illumination optical system  7  includes a plurality of lenses of which only the lens  7   a  is movable in the optical axis direction O 1  and the remaining lenses are all stationary.  
         [0024]    The lens holder  11  is provided on the side surface thereof with long and short racks  11   a  and  11   b  (power varying mechanism) which extend in the optical axis direction. The long rack  11   a  is always engaged with a gear G 1   a  which is located at one end of an upper gear train G 1  and is disengageably engaged with one of gears  13  that is located adjacent to the upper gear train G 1 . The short rack  11   b  is disengageably engaged with both the gears  13 . As shown in FIG. 4, a gear G 1   b  at the other end of the upper gear train G 1  has a rotating shaft  15  to which a gear  17  is secured at the lower end of the shaft. The gear  17  engages with a gear  21  secured to an upper end of a rotation transmission shaft  19  which extends in the upward and downward direction. A gear  23  which is secured to the lower end of the rotation transmission shaft  19  is in mesh with a gear  25  which is in mesh with a pinion P secured to the drive shaft of the motor M. The motor M is connected to the CPU so that the motor M rotates in the forward or reverse direction in accordance with a forward or reverse rotation signal supplied from the CPU. The rotational force is transmitted to the long rack  11   a  through the gears  25 ,  23 ,  21 ,  17  and the upper gear train G 1 , so that the lens holder  11  (lens  7   a ) is moved in the optical axis direction O 1  to vary the focal length of the illumination optical system  7 .  
         [0025]    The mirror M 1  is provided on the side of the illumination optical system  7  away from the white LED  5 . The second mirror M 2  is provided directly below the first mirror M 1 .  
         [0026]    The image pickup optical system  27  is arranged on the right side of the lower mirror M 2  in FIG. 1. The image pickup optical system  27  includes two image pickup optical systems (a first image pickup optical system  29  and a second image pickup optical system  31 ) having different focal lengths, as shown in FIG. 3. The image pickup optical systems  29  and  31  have optical axes O 2  and O 3  extending in parallel with the optical axis O 1 . The first and second image pickup optical systems  29  and  31  are held by an image pickup optical system holder  33  which is, in turn, slidably held by a pair of guide rails  35  perpendicular to the optical axes O 2  and O 3 . The image pickup optical system holder  33  is provided with a rack (image pickup optical system selection mechanism)  33   a  which is always in mesh with a gear G 2   a  located at one end of a lower gear train G 2 . As shown in FIG. 4, a gear G 2   b  at the other end of the lower gear train G 2  is in mesh with the pinion P of the motor M, so that when the motor M is rotated in the forward or reverse direction, the rotational force of the motor M is transmitted to the rack  33   a  through the gear train G 2 . Consequently, the first image pickup optical system  29  or the second image pickup optical system  31  is moved between the mirror m 2  and the linear CCD  37 .  
         [0027]    The scanning operation of the film F 1  or F 2 , using the film scanner constructed as above will be discussed below.  
         [0028]    A power switch (not shown) is turned ON to cause the white LED  5  to emit light and a memory card is inserted in the memory card slot. Thereafter, the Brownie film F 1  is inserted in the film insertion opening of the casing  3 . The film discrimination sensor detects that the inserted film is the Brownie film F 1 . As a result, the motor M is rotated in the forward direction in response to the forward rotation signal supplied from the CPU to the motor M. The rotation of the motor M is transmitted to the lens holder  11  and the image pickup optical system  33  via the upper gear train G 1  and the lower gear train G 2 , etc. Consequently, the lens holder  11  is moved close to the mirror M 1  and the first image pickup optical system  29  is moved to a light path between the mirror M 2  and the linear CCD  37 , as shown in FIGS. 1 through 3. Moreover, an operation signal is supplied from the CPU to the film feeder, so that the brownie film F 1  is moved between the upper and lower mirrors M 1  and M 2 , intermittently by a displacement corresponding to the line pitch of the linear CCD  37 .  
         [0029]    In this position, as shown in FIG. 1, the light transmitted through the illumination optical system  7  is incident upon the mirror M 1  and is reflected thereby downwardly. The reflected light is transmitted through one frame of the Brownie film F 1  at a width corresponding to the line pitch, with a coverage slightly larger than the distance between the opposing sides of a photosensitive surface of the Brownie film F 1 . The light transmitted through the Brownie film F 1  is reflected by the mirror M 2  and is made incident upon the linear CCD  37  via the first image pickup optical system  29 . Consequently, an image whose width corresponds to the line pitch, recorded on the photosensitive surface of the Brownie film F 1  is formed on the entire light receiving surface  37   a  of the linear CCD  37 . Thus, each frame is scanned at a width interval corresponding to the line pitch. The film is moved intermittently by a displacement corresponding to the line pitch by the film feeder, so that one frame can be entirely scanned. Thereafter, a subsequent frame is scanned.  
         [0030]    The object image formed on the light receiving surface  37   a  is converted into electrical image data by the linear CCD  37 . The image data is recorded in an internal memory through a gain control circuit, an A/D converter, a DSP, a memory controller, and the CPU. The CPU is connected to a card controller, so that the image data is recorded also in the memory card inserted in the memory card slot.  
         [0031]    The digital image data processed in the film scanner  1  is converted into analogue data by a D/A converter, so that the analogue image data can be supplied to an external electronic device through a video output terminal.  
         [0032]    When a 35 mm film F 2  is inserted in the film insertion opening, as shown in FIGS. 5 and 6, the film discrimination sensor detects that the inserted film is the 35 mm film F 2 . Consequently, the CPU sends a reverse rotation signal to the motor M, so that the motor M is rotated in the reverse direction. As a result, the lens holder  11  is moved away from the mirror M 1 , the second image pickup optical system  31  is moved in a light path between the mirror M 2  and the linear CCD  37  while the first image pickup optical system  29  is moved out of the light path.  
         [0033]    In this position, as shown in FIG. 6, the light transmitted through the illumination optical system  7  is incident upon the mirror M 1 , wherein the light incident upon the mirror M 1  has a width smaller than that in FIG. 2. The light reflected downward by the mirror M 1  is transmitted through the 35 mm film F 2  at a width corresponding to the line pitch, with a coverage slightly larger than the distance between the opposing sides of a photosensitive surface of the 35 mm film F 2 . The light transmitted through the 35 mm film F 2  is reflected by the mirror M 2  and is made incident upon the linear CCD  37  via the second image pickup optical system  31 . Consequently, an image of a portion corresponding to the line pitch of the 35 mm film F 2  is formed on the entire light receiving surface  37   a  of the linear CCD  37 . The object image formed on the light receiving surface  37   a  is converted into electrical image data which is recorded in an internal memory and the memory card, and can be transmitted to an external electronic device connected to the video output terminal or a personal computer through a digital interface.  
         [0034]    As can be understood from the foregoing, according to the embodiment of the present invention, the light can be received by the entirety of the light receiving surface  37   a  of the linear CCD  37  by selectively using one of the two image pickup optical systems  27  (first image pickup optical system  29  and the second image pickup optical system  31 ) regardless of the kind of film to be used, i.e., the Brownie film F 1  or the 35 mm film F 2 . Thus, the linear CCD  37  does not have a non-utilized area. Moreover, the light emitted from the white LED  5  can be transmitted through the film F 1  or F 2  with a coverage slightly larger than the distance between the opposing sides of the photosensitive surface of the film F 1  or F 2  by varying the power of the illumination optical system  7  depending on the kind of film, i.e., the film F 1  or the film F 2 . Therefore, when the 35 mm film is scanned, the amount of light which can be received by the linear CCD  37  is not reduced, so that a bright image can be obtained.  
         [0035]    Furthermore, since the white LED  5  is used as the light source, it is not necessary to synchronize the timing of the image pickup with the timing of the light emission of the light source, unlike the prior art in which the fluorescent lamp is used. Thus, the image can be always picked up by the linear CCD  37  with a sufficient amount of light.  
         [0036]    In addition, since the white LED  5  consumes less amount of electric power, the cost can be reduced. Note that a light source other than the white LED  5  can be used, for example, an RGB LED.  
         [0037]    Since the illumination optical system  7  and the image pickup optical system  27  are driven by the single drive mechanism having a single drive source (motor M), the drive mechanism can be simplified.  
         [0038]    According to the present invention, even if the operation, in which the focal length can be switched, of the image pickup optical system is carried out, a bright image can be obtained without reducing the amount of light which can be received by the image pickup element.  
         [0039]    Obvious changes may be made in the specific embodiments of the present invention described herein, such modifications being within the spirit and scope of the invention claimed. It is indicated that all matter contained herein is illustrative and does not limit the scope of the present invention.