Slide scanner

Claim 2

A scanner that converts analog information of colour slide transparencies into digital information for storage in a computer memory comprising: (a) means for producing a thin stripe of light much thinner than the length dimension of the slide; (b) a slide carriage for holding a slide; (c) means for moving the slide carriage along a line of movement across the thin stripe of light at predetermined speeds to produce projected analog images; (d) red, green, and blue filters; (e) means for moving the filters sequentially into the projected analog images each for a different period of time to produce filtered images; (f) detector means for detecting the analog images and generating corresponding electrical signals; and (g) means for converting the electrical signals into digital signals suitable for storage in a computer.

Claim 3

A scanner as claimed in Claim 1 wherein the detector means includes an array of CCD devices.

Claim 4

A scanner as claimed in Claim 2 wherein the different periods of time are a function of the responses of the CCD devices to red, green, and blue light.

Claim 5

The scanner claimed in Claim 3 including a neutral density filter as one of the filters and the period of time for the neutral density filter produces an over exposed grey in the CCD array.

Claim 6

A scanner as claimed in any one of Claims 2 to 4 wherein the means for producing a thin stripe of light includes a light source remote from the slide carriage, and optical fibers in the path of light from the light source having an outlet conforming to the thin stripe of light to produce the thin stripe of light.

Claim 7

A scanner as claimed in Claim 5 wherein the filter moving means includes means for stepping the filters one at a time into the projected analog images.

Claim 8

A scanner as claimed in Claim 6 including a lens to focus the projected images onto the CCD array and means to move the lens and filters together towards and away from the CCD array without moving the slide carriage.

Claim 9

A scanner as claimed in any one of Claims 1 to 7 wherein the means for moving the slide carriage includes a motor, a drive shaft driven by the motor in rotation, means to mount the drive shaft for rotation and with its axis parallel to the line of movement of the slide carriage; and skewed rollers on the carriage and the drive shaft that impart linear motion to the carriage from the rotation of the drive shaft.

Claim 10

A scanner as claimed in Claim 8 including an outrigger on the carriage extending normal to the axis of the drive shaft and guide for the outrigger to bear on and react torque of the drive shaft imparted to the carriage.

Claim 11

A scanner as claimed in Claim 9 wherein the guide includes a guide shaft parallel to the drive shaft and the outrigger includes a roller engaging the guide shaft.

Claim 12

A scanner as claimed in any one of Claims 8 to 10 wherein the skewed rollers comprise at least two pairs of rollers mounted to the carriage at spaced apart locations along the line of movement with the two rollers of each pair resting on and straddling the drive shaft to support the weight of the carriage by the drive shaft with no forces other than the weight of the carriage and the drive forces of the drive shaft acting between the carriage and the drive shaft.

Claim 13

A scanner that converts analog information of colour slide transparencies into digital information for storage in a computer memory comprising: (a) a base; (b) a light source mounted on the base; (c) a fibre optic bundle having an entrance and an exit and mounted to the base, the exit of the fibre optic bundle being in the shape of a long and narrow stripe to project a thin stripe of light from the light source; (d) a slide carriage for holding a slide; (e) means for moving the slide carriage linearly across the stripe of light; (g) red, green, blue, and neutral density filters; (h) a filter mount holding the filters for serial interception of images from a slide in the slide carriage projected by the slide of light to create superimposable images; (i) means to present each of the filters serially for the interception of the images and to produce filtered images, the presentation being for a period of time selected for each of the filters; (j) a lens mounted to the base for movement towards and away from the CCD means and the slide carriage for focusing the image on the CCD means, the lens and the filter mount being counted together for this movement; (k) CCD detector means for detecting the images from the filters superimposed for each stripe and converting them into analog electrical signals, the different periods of time being a function of the response of the CCD detector means to the particular light striking it, the period of time for the neutral distance filter being sufficient to overexpose the CCD detector means except for shadowy areas of the slide; and (l) means for converting the electrical analog signals into digital signals suitable for storage in a computer.

Claim 14

A scanner that converts analog information of colour slide transparencies into digital information for storage in a computer memory comprising: (a) a base; (b) a light source mounted on the base; (c) a fibre optic bundle having an entrance and an exit and mounted to the base, the exit of the fibre optic bundle being in the shape of a long and narrow stripe to project a thin stripe of light from the light source; (d) a slide carriage for holding a slide; (e) means for moving the slide carriage linearly across the stripe of light; (g) red, green, blue, and neutral density filters; (h) a filter mount holding the filters for serial interception of images from a slide in the slide carriage projected by the slide of light to create superimposable images; (i) means to present each of the filters serially for the interception of the images and to produce filtered images, the presentation being for a period of time selected for each of the filters; (j) a lens mounted to the base for movement towards and away from the CCD means and the slide carriage for focusing the image on the CCD means, the lens and the filter mount being counted together for this movement; (k) CCD detector means for detecting the images from the filters superimposed for each stripe and converting them into analog electrical signals, the different periods of time being a function of the response of the CCD detector means to the particular light striking it, the period of time for the neutral distance filter being sufficient to overexpose the CCD detector means except for shadowy areas of the slide; and (l) means for converting the electrical analog signals into digital signals suitable for storage in a computer.

Claim 15

A scanner as claimed in Claim 12 wherein the slide carriage moving means includes a drive shaft mounted to rotate on the base around an axis normal to the direction of projection, means to drive the drive shaft in rotation, and roller means coupling the carriage and the drive shaft to impart linear motion to the carriage upon rotation of the drive shaft.

Claim 16

A scanner as claimed in Claim 12 or in Claim 13 including a fan to cool the light source, the fan and light source being remote from the slide carriage so that heat from the light source does not deflect the slide.

Claim 17

A scanner as claimed in Claim 13 or Claim 14 wherein the roller means includes at least two pair of skewed rollers mounted at spaced apart locations along the drive shaft to the carriage in position to transmit the weight of the carriage to the drive shaft, the rollers being the only things that transmit forces between the drive shaft and the carriage.

Claim 18

A scanner as claimed in Claim 15 wherein the filter presentation means includes a stepper motor and drive coupled to the filter mount to progessively step each filter for the interception of the images.

Claim 19

A scanner as claimed in Claim 16 wherein the stepper motor and drive includes a crank drive and a stepper shaft, the stepper motor driving the stepper shaft, the stepper shaft driving the crank, the crank translating the filter mount, the stepper shaft having coupler means to permit relative movement between the filter mount and crank on the one hand and the stepper motor on the other in response to focusing movement of the lens.

Claim 20

A scanner as claimed in Claim 17 wherein the lens is mounted in a lens assembly having opposed wings that guide on linear tracks attached to the base.

Claim 21

A scanner as claimed in Claim 18 wherein the linear tracks restrain the lens assembly in all but one degree of freedom.

Claim 22

A scanner as claimed in any one of Claims 12 to 19 including a light condenser between the light source and the entrance to the optical fibre bundle to concentrate the light entering the optical bundle.