Apparatus and method for fabricating a lenticular plate

• US 6,226,131 B1
• Filed: 09/25/1998
• Issued: 05/01/2001
• Est. Priority Date: 09/25/1997
• Status: Expired due to Term

• Current Assignee: Hanger Solutions, LLC (IP Investments Group LLC)
• Original Assignee: Korea Advanced Institute of Science and Technology
• Inventors: Son, Jung Young, Smirnov, Vadim V.
• Primary Examiner(s): Epps, Georgia
• Assistant Examiner(s): SPECTOR, DAVID N
• Application Number:
  US09/160,590
• Time in Patent Office: 949 Days
• Field of Search: 340/320, 340/321, 340/494, 340/496, 347/224, 347/256, 347/258, 355/53, 359/454, 359/455, 359/619-628, 359/738, 362/257, 362/259, 362/311
• US Class Current: 359/738
• CPC Class Codes: B23K 26/066 by using masks
• CPC Class Codes: G02B 3/0012 characterised by the manufacturing method
• CPC Class Codes: G02B 3/005 arranged along a single direction only, e.g. lenticular sheets G02B3/0043 takes precedence
• CPC Class Codes: G03B 21/602 Lenticular screens G03B21/625 takes precedence
• CPC Class Codes: G03B 21/625 Lenticular translucent screens

Abstract

An apparatus for fabricating a lenticular plate by irradiating with laser light a plate to which a photosensitive material is deposited. The apparatus for fabricating a lenticular plate comprises a collimator for collimating a beam from a laser to a predetermined diameter, a mask for adjusting the intensity distribution of the collimated beam, a photoplate on which a layer of photosensitive material is deposited, means for directing the beam which has passed through the mask to a desired region of the photoplate, and means for controlling the mask and the means for directing the beam such that the beam of predetermined intensity distribution irradiates on the desired region of the photoplate.

Claims

1. An apparatus for fabricating a lenticular plate, the apparatus comprising:

a collimator for collimating a beam from a laser to a predetermined diameter;

a mask for adjusting the intensity distribution of the collimated beam to provide a laser beam with a predetermined intensity distribution;

a photoplate on which a layer of a photosensitive material is deposited;

means for directing the laser beam from said mask to a desired region of said photoplate, said directing means including means for adjusting the size of the region of said photoplate on which the beam reaches and means for moving the beam in a direction which is perpendicular to the beam; and

means for controlling said mask and said directing means such that the laser beam irradiates on the desired region of said photoplate.

2. The apparatus of claim 1 wherein said mask is operated using a predetermined transmission function such that the collimated beam has the predetermined intensity distribution after it has passed through said mask.

3. The apparatus of claim 2 wherein the predetermined transmission function T(y) is given by:

$T<br><br>\left(y\right)=\frac{y^2}{{\mathrm{\omega <br><br>}}_0^2}+\mathrm{\alpha <br><br>}<br><br>\sqrt{R^2-y^2}+\ln <br><br>\frac{I_c}{I_0}-\mathrm{\alpha <br><br>}·<br><br>l-\ln <br><br>\left\{{\int <br><br>}_{-\mathrm{\infty <br><br>}}^{\mathrm{\infty <br><br>}}<br><br>{\mathrm{<br><br>}}^{-\frac{x^2}{{\mathrm{\omega <br><br>}}_0^2}}<br><br><br><br>x·<br><br>T<br><br>\left(x\right)\right\}$

where x is a coordinate value on a longitudinal axis of a cylindrically symmetric lens to be formed on the photoplate, y is a coordinate value on lens pitch axis of the cylindrically symmetric lens, ω

₀ is a radius of the beam at 1/e² intensity level, α

is absorption coefficient of the photosensitive material, R is the radius of curvature of the cylindrically symmetric lens, I₀ is the intensity of the beam on the center of the beam, I_c is the intensity of the beam needed to form a lens of desired thickness in the y direction, and T(x) is a predetermined function.

4. The apparatus of claim 3 wherein the beam has different diameters in the x and y directions.

5. The apparatus of claim 2 wherein said mask is comprised of a material which passes the beam, the material of said mask having density distribution which is proportional to the predetermined transmission function.

6. The apparatus of claim 2 wherein said mask is comprised of a material which passes the beam, the thickness distribution of the material of said mask being proportional to the predetermined transmission function.

7. The apparatus of claim 3 wherein said mask is a spatial light modulator which modulates the beam such that the intensity distribution of the beam becomes proportional to the predetermined transmission function.

8. The apparatus of claim 1 wherein said means for directing the beam further comprises:

means for adjusting the size of the region of said photoplate on which the beam reach; and

means for moving said photoplate in a direction which is perpendicular to the beam.

9. The apparatus of claim 8 wherein said means for adjusting the size of the region of said photoplate is an optical lens including an optical diffraction element.

10. The apparatus of claim 1 wherein the photosensitive material is a light hardening material which hardens by the irradiation of a laser beam.

11. The apparatus of claim 10 wherein the light hardening material contains photo sensitizers which absorbs a laser beam.

12. The apparatus of claim 11 wherein the shape of the lens to be made on the photoplate is determined by the predetermined intensity distribution of the beam and the absorption coefficient of the sensitizers.

13. The apparatus of claim 10 wherein the light hardening material is dichromated gelatine (DCG).