Prism assembly

• US 20060044654A1
• Filed: 08/25/2005
• Published: 03/02/2006
• Est. Priority Date: 09/01/2004
• Status: Active Grant

• Current Assignee: Naamloze Vennootschap Barco
• Original Assignee: Naamloze Vennootschap Barco
• Inventors: Vandorpe, Krist, Gerets, Peter, Lesschaeve, Stefan, Coulier, Nico
• Granted Patent: US 7,576,932 B2
• Time in Patent Office: Days
• US Class Current: 359/834
• CPC Class Codes: G02B 17/04 using prisms only
• CPC Class Codes: G02B 27/0006 with means to keep optical surfaces clean, e.g. by preventing or removing dirt, stains, contamination, condensation G02B1/18 takes precedence; cleaning in general B08B
• CPC Class Codes: G02B 27/1026 for use with reflective spatial light modulators
• CPC Class Codes: G02B 27/145 having sequential partially reflecting surfaces
• CPC Class Codes: G02B 5/04 Prisms
• CPC Class Codes: G03B 21/00 Projectors or projection-type viewers; Accessories therefor devices for changing pictures G03B23/00
• CPC Class Codes: G03B 21/005 Projectors using an electronic spatial light modulator but not peculiar thereto
• CPC Class Codes: H04N 9/3105 for displaying all colours simultaneously, e.g. by using two or more electronic spatial light modulators simultaneous projection in colour photography G03B33/10; beam splitting or combining systems per se G02B27/10

Abstract

A prism assembly, including two or more prisms, at least one of which has or more surfaces that are used for total internal reflection or partial spectral reflection of incoming light, wherein at least a part of one of the surfaces used for reflection purposes is covered with an element that is spaced apart from the surface, such that a gap is defined in between the surface and the element, and wherein the gap is sealed with a seal that is applied on one of said prisms in order to prevent contaminants from entering the gap.

Claims

1. A prism assembly, comprising two or more prisms, at least one of which comprises one or more surfaces that are used for total internal reflection or partial spectral reflection of incoming light, wherein at least a part of one of said surfaces used for reflection purposes is covered with an element that is spaced apart from said surface, such that a gap is defined in between said surface and said element, and wherein said gap is sealed with a seal that is applied on one of said prisms in order to prevent contaminants from entering said gap.

2. The prism assembly according to claim 1, wherein said element comprises another prism of said prism assembly.

3. The prism assembly according to claim 1, wherein said element comprises a plate.

4. The prism assembly according to claim 1, wherein said element comprises a light reflecting valve.

5. The prism assembly according to claim 1, wherein said seal comprises at least a sealant.

6. The prism assembly according to claim 5, wherein said sealant is only applied on places of the prisms that are not involved in reflecting incoming light relevant for image building.

7. The prism assembly according to claim 6, wherein all parts of the surfaces reflecting incoming light relevant for image building are covered with said element.

8. The prism assembly according to claim 5, wherein said sealant is heat resistant to temperatures up to 80°

C. and is resistant to ultra violet light.

9. The prism assembly according to claim 5, wherein said sealant comprises silicone.

10. The prism assembly according to claim 5, wherein said sealant comprises silicon rubber.

11. A digital light processing prism apparatus comprising a total internal reflection (TIR) prism assembly and a color prism assembly, wherein the TIR-prism assembly comprises two triangular prisms extending in a first direction, said TIR-prisms facing each other with one of their surfaces, wherein the color prism assembly comprises a quadrangular prism and two triangular prisms which are oriented in a transversal direction in view of the TIR-prisms, and wherein the quadrangular prism has one surface facing a surface of a first of said color triangular prisms, said first triangular prism having a second surface facing a first surface of the second color triangular prism, said second color prism having a second surface, partially facing a surface of one of said TIR-prisms, wherein all of said facing surfaces are located at a mutual distance of each other, such that a gap is formed in between each of said facing surfaces, and wherein said gaps are sealed with a seal that is applied on said prisms.

12. The digital light processing prism apparatus according to claim 11, wherein each of the color prisms are provided at one of their surfaces with a light reflecting valve, wherein said light reflecting valves are spaced apart from the corresponding surfaces such that a gap is formed in between said light reflecting valves and their correspondent surface, and wherein said gaps are sealed with a seal applied on said light reflecting valves and said prisms.

13. The digital light processing prism apparatus according to claim 11, wherein the outwardly oriented surfaces of the TIR-prisms and the outwardly oriented surfaces of the color prisms that are usable for total internal reflection or partial spectral reflection of an image building part of the incoming light, are covered with an element that is spaced apart from said surface, such that a gap is defined in between said surface and said element, and wherein said gap is sealed with a seal that is applied on one of said prisms in order to prevent contaminants from entering said gap.