Holographic foil and method for producing same

Patent metadata

Field	Value
Publication number	US-9964679-B2
Application number	US-201414783833-A
Country	US
Kind code	B2
Filing date	Apr 3, 2014
Priority date	Apr 9, 2013
Publication date	May 8, 2018
Grant date	May 8, 2018

Abstract

Described is a holographic film ( 100 ) whose transmission and/or reflection properties vary periodically along at least one of its directions of principal extent, said film being designed for at least partial transmission ( 22, 28 ) of light ( 20, 26 ) of at least one first wavelength range that is irradiated from a multiplicity of periodically disposed illuminants ( 200 ) and that impinges on the holographic film ( 100 ). Also described are a lighting means ( 300 ), a backlighting means and a method for producing a holographic film ( 100 ).

First claim

The invention claimed is:

1. A holographic foil, whose transmission and/or reflection properties vary periodically in at least one of its main extension directions and which is designed to at least partially transmit light from at least one first wavelength range emitted by each of a multiplicity of periodically arranged lighting means and impinging upon the holographic foil, the holographic foil comprising:
a first multiplicity of periodically arranged regions which are formed as reflection holograms, designed to reflect light of the first wavelength range, and
a second multiplicity of periodically arranged regions which are formed as transmission holograms, designed to transmit light of the first wavelength range,
wherein the transmission holograms are each formed in a ring-shaped manner around one of the reflection holograms, respectively.

2. The holographic foil according to claim 1 , wherein the reflection holograms are arranged at regular intervals in at least one main extension direction of the holographic foil.

3. The holographic foil according to claim 2 , wherein the regular intervals are between 5 cm and 40 cm.

4. The holographic foil according to claim 1 , wherein the reflection holograms are designed to partially diffusely reflect light emitted by the lighting means.

5. The holographic foil according to claim 1 , wherein the center points of the ring-shaped transmission holograms are arranged at regular intervals in at least one main extension direction of the holographic foil.

6. The holographic foil according to claim 1 , wherein the transmission holograms are designed to collimate light, emitted by the lighting means and transmitted by the transmission holograms, in a main emission direction.

7. A method for producing a holographic foil according to claim 1 , comprising the following method steps:
providing a layer consisting of a holographic material; and
exposing the layer to light using at least one reference wave from the first wavelength range in a reference direction and at the same time using at least one first signal wave from the first wavelength range,
wherein the signal wave is radiated in a first multiplicity of regions on the other side of the layer to the reference wave, and
wherein the signal wave is radiated in a second multiplicity of regions on the same side of the layer as the reference wave.

8. An illumination device, comprising:
a first multiplicity of periodically arranged lighting means which are designed to emit light from at least one first wavelength range; and
a holographic foil, whose transmission and reflection properties vary periodically in at least one of its main extension directions and which is designed to at least partially transmit light from the at least one first wavelength range emitted by each of the first multiplicity of periodically arranged lighting means and impinging upon the holographic foil,
wherein the holographic foil comprises
a first multiplicity of periodically arranged regions which are formed as reflection holograms, designed to reflect light of the at least one first wavelength range, and
a second multiplicity of periodically arranged regions which are formed as transmission holograms, designed to transmit light of the first wavelength range, wherein the transmission holograms are each formed in a ring-shaped manner around one of the reflection holograms, respectively, and

wherein at each of the lighting means, the region of the holographic foil is formed as a reflection hologram in each case, which region is arranged downstream of the respective lighting means in a viewing direction perpendicular to two main extension directions of the holographic foil such that the light of the at least one first wavelength range, which is transmitted through the holographic foil, has a homogeneous light density.

9. The illumination device according to claim 8 , wherein the first multiplicity of periodically arranged lighting means includes a multiplicity of light-emitting diodes.

10. The illumination device according claim 8 , further comprising a diffuser which is designed to diffusely scatter the light transmitted from the holographic foil.

11. The illumination device according to claim 8 , further comprising:
a third multiplicity of periodically arranged lighting means which are designed to emit light from at least one second wavelength range; and
a fourth multiplicity of periodically arranged lighting means which are designed to emit light from at least one third wavelength range,
wherein the holographic foil is further designed to at least partially transmit light emitted by each of the third multiplicity of lighting means and impinging upon the holographic foil, and
wherein the holographic foil is further designed to at least partially transmit light emitted by each of the fourth multiplicity of lighting means and impinging upon the holographic foil.

12. A back-lighting device, comprising:
an illumination device according to claim 8 ; and
holding means for an element to be backlit.

13. A holographic foil, whose transmission and/or reflection properties vary periodically in at least one of its main extension directions and which is designed to at least partially transmit light from at least one first wavelength range emitted by each of a multiplicity of periodically arranged lighting means and impinging upon the holographic foil, the holographic foil comprising:
a first multiplicity of periodically arranged regions which are formed as reflection holograms; and
a second multiplicity of periodically arranged regions which are formed as transmission holograms,
wherein the transmission holograms are each formed in a ring-shaped manner around one of the reflection holograms, respectively,
wherein the transmission and reflection properties of the holographic foil vary with the same period which is provided for the periodic arrangement of the lighting means so that a homogeneous light density can be achieved.

14. The holographic foil according to claim 13 , wherein the center points of the ring-shaped transmission holograms are arranged at regular intervals in at least one main extension direction of the holographic foil, and
wherein the regular intervals are between 5 cm and 40 cm.

Assignees

• Osram Opto Semiconductors Gmbh
• Osram Opto Semiconductors Gmbh

Inventors

• Morgott Stefan
• Reill Joachim
• Brick Peter

Classifications

• G03H2001/0415

  for recording reflection holograms · CPC title

• G02F1/133606

  including a specially adapted diffusing, scattering or light controlling members · CPC title

• G02B5/1866

  Transmission gratings characterised by their structure, e.g. step profile, contours of substrate or grooves, pitch variations, materials (G02B5/1809, G02B5/1828, G02B5/1833, G02B5/1838 and G02B5/1847 take precedence) · CPC title

• G03H2001/0439

  for recording Holographic Optical Element [HOE] · CPC title

• G02B5/0263

  with positional variation of the diffusing properties, e.g. gradient or patterned diffuser · CPC title