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Projection device for projecting an original image onto a screen

  • US 5,552,938 A
  • Filed: 03/28/1995
  • Issued: 09/03/1996
  • Est. Priority Date: 04/26/1991
  • Status: Expired due to Fees
First Claim
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1. A projection device for projecting an original image formed by an image information forming means onto a screen, comprising:

  • projection lens means having, in succession from a screen side to an original image side, a first lens unit comprising, in succession from the screen side, a front sub-lens unit of negative refractive power and a rear sub-lens unit of positive refractive power and having a positive refractive power as a whole, and a second lens unit having a plurality of lenses and having positive refractive power as a whole, wherein one of the sub-lens units is moved to effect focusing, and wherein an air gap between the front sub-lens unit and the rear sub-lens unit is changed to thereby effect focusing;

    a light source for emitting a light beam; and

    reflecting means disposed between the first lens unit and the second lens unit to reflect the light beam from said light source toward the second lens unit in order to illuminate the image information forming means.

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