Photograph printing device

• US 6,456,359 B1
• Filed: 08/02/1999
• Issued: 09/24/2002
• Est. Priority Date: 08/04/1998
• Status: Expired due to Fees

• Current Assignee: Noritsu Koki Co., Ltd.
• Original Assignee: Noritsu Koki Co., Ltd.
• Inventors: Tsukamoto, Kazuya, Nishikawa, Hidetoshi
• Primary Examiner(s): Adams, Russell
• Assistant Examiner(s): FULLER, RODNEY EVAN
• Application Number:
  US09/366,023
• Time in Patent Office: 1,149 Days
• Field of Search: 355/43, 355/67, 355/71, 348/751, 348/756, 348/761, 348/766, 359/629, 359/630, 359/196, 359/212, 359/223, 359/225, 359/237, 359/245, 359/263, 359/298, 359/303, 359/85
• US Class Current: 355/43
• CPC Class Codes: B41J 2/465 using masks, e.g. light-switching masks
• CPC Class Codes: G02B 27/283 used for beam splitting or combining
• CPC Class Codes: H04N 5/7458 the modulator being an array of deformable mirrors, e.g. digital micromirror device [DMD]

Abstract

A PBS for guiding light from a light source to a DMD as light modulating means as well as for guiding light modulated by the DMD to photographic paper is provided on an optical path between the light source and the DMD. The DMD is arranged so that light from the PBS perpendicularly enters itself, and is equipped with a plurality of micromirrors which swing in accordance with image data. This arrangement allows optical components to be disposed so that an angle of incidence of light with respect to the DMD is 0°, thereby enabling tight layout of the light source section. In other words, there is no need to spread the optical components around the light modulating means like in the conventional cases where an angle of incidence with respect to the light modulating means is more or less required. Besides, since the micromirrors are positioned so as to be substantially symmetric with respect to an optical axis connecting the PBS and the DMD, respective distances from the light source to the micromirrors are substantially equal.

Claims

1. A photograph printing device for printing an image by selectively evenly exposing a photosensitive material layer to light, said photograph printing device comprising:

a light source;

light modulating means including a plurality of elements corresponding to pixels of the image to be printed for modulating light from said light source in accordance with image data; and

an optical element positioned in an optical path between said light source and said light modulating means, said optical element being adapted for guiding light from said light source to said light modulating means, and for guiding light from said light modulating means to said photosensitive material layer;

wherein said light modulating means comprises a digital micromirror device including a plurality of micromirrors, each said micromirror being separately attached to an underlying substrate and defining an outwardly facing reflective surface, said micromirrors being arranged in a matrix form so as to correspond to said pixels and being adapted for movement relative to said optical element and to said underlying substrate in accordance with said image data such that (a) for exposure of said photosensitive material layer at locations corresponding to selected ones of said pixels, the light reflecting surfaces of the micromirrors corresponding to said selected ones of said pixels are set perpendicular to an optical axis perpendicularly connecting said optical element and said light modulating means; and

(b) for non-exposure of said photosensitive material layer at locations corresponding to non-selected ones of said pixels, the light reflecting surfaces of the micromirrors corresponding to the non-selected ones of said pixels are set at angles relative to said optical axis such that light reflected therefrom cannot reach said photosensitive layer via said optical element.

2. The photograph printing device as set forth in claim 1, wherein said light modulating means is disposed so that light from said optical element is made incident perpendicularly onto said light modulating means.

3. The photograph printing device as set forth in claim 1, wherein said light modulating means reflects light from said optical element at least at pixels to expose said photosensitive material, so as to cause the light to again enter said optical element.

4. A photograph printing device as set forth in claim 1, wherein said light modulating means causes light to outgo therefrom in a direction opposite to a direction of incidence of light from said optical element, at least at pixels to expose said photosensitive material.

5. The photograph printing device as set forth in claim 1, further comprising phase difference generating means for generating a phase difference between a horizontal component and a vertical component of incident light, said phase difference generating means being positioned in an optical path between said optical element and said light modulating means.

6. The photograph printing device as set forth in claim 5, wherein light having been transmitted through said phase difference generating means twice in going and returning is equivalent to light obtained by imparting a phase difference of an odd number of times of one half wave length between a horizontal component and a vertical component of the light before the transmission through said phase difference generating means.

7. The photograph printing device as set forth in claim 6, wherein said phase difference generating means is composed of a quarter wave length plate.

8. The photograph printing device as set forth in claim 6, wherein said optical element is a polarizing beam splitter.

9. The photograph printing device as set forth in claim 8, wherein said polarizing beam splitter transmits the light from said light source, and reflects the light from said light modulating means.

10. The photograph printing device as set forth in claim 8, wherein said polarizing beam splitter reflects the light from said light source, and transmits the light from said light modulating means.

11. The photograph printing device as set forth in claim 1, further comprising a condenser lens in an optical path between said light source and said optical element.

12. The photograph printing device as set forth in claim 1, further comprising a printing lens in an optical path between said optical element and said photosensitive material.

13. The photograph printing device as set forth in claim 1, wherein said light modulating means has a light modulating region which is provided symmetrically with respect to a plane including said optical axis connecting said optical element and said light modulating means.