LED illuminating device for providing a uniform light spot

• US 6,033,087 A
• Filed: 12/23/1997
• Issued: 03/07/2000
• Est. Priority Date: 12/26/1996
• Status: Expired due to Fees

• Current Assignee: PATLITE Corporation. (Inaba Denkisangyo Company Limited)
• Original Assignee: PATLITE Corporation. (Inaba Denkisangyo Company Limited)
• Inventors: Shozo, Hitora, Kawashima, Tokio
• Primary Examiner(s): Tso, Laura K.
• Application Number:
  US08/997,596
• Time in Patent Office: 805 Days
• Field of Search: 362/19, 362/33, 362/231, 362/244, 362/246, 362/800
• US Class Current: 362/244
• CPC Class Codes: F21V 5/02 of prismatic shape F21V5/04 takes precedence
• CPC Class Codes: F21V 5/04 of lens shape
• CPC Class Codes: F21Y 2115/10 Light-emitting diodes [LED]
• CPC Class Codes: G01N 21/8806 Specially adapted optical and illumination features
• CPC Class Codes: Y10S 362/80 Light emitting diode

Abstract

An illuminating device including a cylindrical main body that is provided with a circularly arranged plurality of LEDs of different colors so as to be used in, for instance, an optical inspection apparatus. The illuminating device further includes a light diffusing element, light-condensing lens and a polarizing element or a prism having polarizing surfaces, which are all installed inside the cylindrical main body. The LED lights are corrected in intensity to be even by the light-diffusing element, pass through the light-condensing lens and further pass through the prism so as to be directed toward a single point and form a superimposed light illuminating an object, thus a CCD camera that is provided in the center of the cylindrical main body can take an image of the object.

Claims

1. An LED illuminating device comprising:

an LED assembly on which a plurality of LED elements are mounted in a prescribed arrangement;

a polarizing optical means provided in a light beam path of said plurality of LED elements for polarizing light from said LED elements and for superimposing light from each of said plurality of LED elements at a prescribed focal distance; and

a holding means which holds said LED assembly and said polarizing optical means;

whereby illuminating light of a uniform intensity is provided.

2. An LED illuminating device characterized in that said device comprises:

an LED assembly on which a plurality of LED elements are mounted in a prescribed arrangement;

a condensing optical means and a polarizing optical means provided successively in a light beam path of said plurality of LED elements; and

a holding means which holds said LED assembly, condensing optical means and polarizing optical means, and wherein

LED illuminating light beams are susperimposed at a prescribed focal distance.

4. An LED illuminating device according to claim 2 or 3, wherein said polarizing optical means is a polarizing prism which includes a first polarizing surface formed on a source thereof that faces said LEDs and a second polarizing surface formed on a surface thereof facing a surface that is to be illuminated.

5. An LED illuminating device according to claim 2 or 3, wherein said plurality of LED elements comprises LED elements of a plurality of colors, and a control means is provided for controlling a quantity of light of said LED elements.

6. An LED illuminating device according to claim 4, wherein said plurality of LED elements comprises LED elements of a plurality of colors, and a control means is provided for controlling a quantity of light of said LED elements.

3. An LED illuminating device characterized in that said device comprises:

an LED assembly on which a plurality of LED elements are mounted in a prescribed arrangement;

a condensing optical means, a diffusing optical means, a polarizing optical means and a partially light-blocking means provided successively in a light beam path of said plurality of LED elements; and

a holding means which holds said LED assembly, condensing optical means, diffusing optical means, polarizing optical means and light-blocking means; and

wherein

LED illuminating light beams are superimposed at a prescribed focal distance.

7. An illuminating device characterized in that said device comprises:

a device housing comprising a hollow cylindrical body;

a plurality of LEDs provided in said device housing so as to be arranged circularly near one end of said device housing; and

a doughnut-shape polarizing optical means provided near another end of said device housing, said polarizing optical means having at least one diffusion surface so as to polarize from said LEDs and for superimposing light from each of said plurality of LEDs at a prescribed focal distance;

whereby illuminating light of a uniform intensity is provided.

8. An illuminating device characterized in that said device comprises:

a device housing comprising a hollow cylindrical body;

a plurality of LEDs provided in said device housing so as to be arranged circularly near one end of said device housing;

a doughnut-shaped polarizing optical means provided near another end of said device housing, said polarizing optical means having at least one diffusion surface so as to polarize light from said LEDs; and

a doughnut-shaped condensing optical means provided between said plurality of LEDs and said polarizing optical means, said condensing optical means comprising a plurality of lens surfaces which are arranged so as to positionally correspond to said plurality of LEDs.

9. An illuminating device according to claim 8, wherein said plurality of LEDs emit different colors.

10. An illuminating device according to claim 8 or 9, further comprising a imaging means provided at said one end of said device housing, an optical axis of said imaging means being aligned on a center axis of said cylindrical device housing so that said lights from said LEDs are polarized toward said optical axis of said imaging means.