Image display device and method of manufacturing a light conductor for such an image display device

• US 6,396,637 B2
• Filed: 05/01/2001
• Issued: 05/28/2002
• Est. Priority Date: 05/04/2000
• Status: Expired due to Fees

• Current Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Original Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Inventors: Roest, Wouter, Van Santen, Helmar
• Primary Examiner(s): Dang, Hung Xuan
• Assistant Examiner(s): TRA, TUYEN Q
• Application Number:
  US09/846,460
• Publication Number:
  US 20010055142A1
• Time in Patent Office: 392 Days
• Field of Search: 359/301,302,487,627,483,485,486,630
• US Class Current: 359/627
• CPC Class Codes: G02B 6/0038 Linear indentations or grooves, e.g. arc-shaped grooves or meandering grooves, extending over the full length or width of the light guide
• CPC Class Codes: G02B 6/0056 for producing polarisation effects, e.g. by a surface with polarizing properties or by an additional polarizing elements
• CPC Class Codes: G02F 1/133536 Reflective polarizers G02F1/13362 takes precedence
• CPC Class Codes: G02F 1/133545 Dielectric stack polarisers
• CPC Class Codes: G02F 1/133615 Edge-illuminating devices, i.e. illuminating from the side
• CPC Class Codes: G02F 1/133616 Front illuminating devices
• CPC Class Codes: G02F 1/13362 providing polarized light, e.g. by converting a polarisation component into another one
• CPC Class Codes: G02F 2203/02 reflective

Abstract

An image display device comprising a light modulation panel, a light conductor arranged opposite the light modulation panel and a light source connected to the light conductor. The light conductor comprises a serrated foil which reflects a light beam emitted by the light source and having a first direction of polarization, and transmits a light beam modulated by the light modulation panel and having a second direction of polarization.

Claims

1. An image display device comprising a light modulation panel, a light conductor situated opposite the light modulation panel, and a light source coupled to the light conductor, characterized in that the light conductor comprises a serrated foil which is reflective to a light beam emitted by the light source and having a first direction of polarization, and transparent to a light beam modulated by the light modulation panel and having a second direction of polarization.

2. An image display device as claimed in claim 1, characterized in that the serrated foil has a plurality of juxtaposed sawtooth-shaped projections each comprising a first and a second face, a first face situated closer to the light source and facing the light source enclosing a larger angle with respect to the light modulation panel than a first face situated further remote from the light source and facing the light source.

3. An image display device as claimed in claim 2, characterized in that the image display device comprises at least a second light source situated on a side of the light modulation panel remote from the first light source, in which a second face situated closer to the second light source and facing the second light source encloses a larger angle with respect to the light modulation panel than a second face situated further remote from the second light source and facing the second light source.

4. An image display device as claimed in any one of the preceding claims, characterized in that the serrated foil is connected on at least one side to a sawtooth-shaped, light-transmissive support.

5. An image display device as claimed in claim 3, characterized in that the foil is provided with the sawtooth-shaped projections by means of pressing between two facing mold parts.

6. An image display device as claimed in claim 5, characterized in that the mold parts constitute optical elements which are provided with complementary teeth, the foil being connected to the optical elements.

7. A method of manufacturing a light conductor suitable for an image display device as claimed in claim 6, characterized in that a foil is positioned between two sawtooth-shaped mold parts, whereafter the mold parts are moved towards each other, thus providing the foil with sawtooth-shaped projections.

8. A method as claimed in claim 7, characterized in that the foil is a reflective polarizer.

9. A method as claimed in claim 7 or 8, characterized in that the mold parts constitute optical elements, in which the foil is connected to the mold parts during the provision of the sawtooth-shaped projections by means of the mold parts.