High efficiency monolithic glass light shaping diffuser and method of making

• US 6,158,245 A
• Filed: 08/25/1998
• Issued: 12/12/2000
• Est. Priority Date: 07/29/1997
• Status: Expired due to Term

• Current Assignee: United California Bank (Los Angeles, California) (Old) (BNP Paribas S.A.)
• Original Assignee: Physical Optics Corporation
• Inventors: Savant, Gajendra D.
• Primary Examiner(s): VINCENT, SEAN E
• Application Number:
  US09/139,379
• Time in Patent Office: 840 Days
• Field of Search: 65/17.2
• US Class Current: 65/17.2
• CPC Class Codes: C03B 19/12 by liquid-phase reaction processes
• CPC Class Codes: C03C 1/008 for the production of films or coatings
• CPC Class Codes: C03C 17/007 containing a dispersed phase, e.g. particles, fibres or flakes, in a continuous phase
• CPC Class Codes: C03C 17/02 with glass C03C17/34, C03C17/44 take precedence
• CPC Class Codes: C03C 2217/213 SiO2
• CPC Class Codes: C03C 2217/77 Coatings having a rough surface
• CPC Class Codes: C03C 2218/113 by sol-gel processes
• CPC Class Codes: C03C 2218/32 After-treatment
• CPC Class Codes: G02B 5/021 the diffusion taking place at the element's surface, e.g. by means of surface roughening or microprismatic structures
• CPC Class Codes: G02B 5/0247 by means of voids or pores
• CPC Class Codes: G02B 5/0252 using holographic or diffractive means
• CPC Class Codes: G02B 5/0268 characterized by the fabrication or manufacturing method
• CPC Class Codes: G02B 5/0278 used in transmission
• CPC Class Codes: G02B 5/0294 adapted to provide an additional optical effect, e.g. anti-reflection or filter
• CPC Class Codes: G02B 5/32 Holograms used as optical elements

Abstract

A surface light shaping diffuser (LSD) is formed from a monolithic glass material by recording light shaping structures on a surface of the material during its formation. A surface LSD is produced by embossing or molding light shaping structures onto a high quality optical glass or by embossing light shaping structures on a glass film layer coated onto a substrate. A rubber submaster carrying the light shaping structures is used as the master in such diffusers control the angular spread of transmitted light while homogenizing otherwise spatially noisy light sources such as LCDs and filamented light sources and while maintaining damage thresholds consistent with any glass optical element. The surface LSD has a transmission efficiency of over 90% from the Ultraviolet wavelengths through the physical spectrum and into the near-infrared.

Claims

1. A method of making a light shaping surface diffuser, the method comprising the steps of:

providing a diffuser submaster of a relatively soft flexible material with at least a first surface and having a plurality of light shaping structures carried on the first surface;

forming a monolithic oxide glass substrate from a solution of a sol-gel material comprising;

recording the plurality of light shaping structures from the diffuser submaster onto a surface of the glass substrate; and

heat treating the glass substrate at a temperature greater than or equal to approximately 1000°

C.

2. The method according to claim 1, wherein the step of forming further comprises:

preparing the solution from a metal alkoxide, an amount of water and a solvent;

causing a sol-to-gel transition of the solution to form a gel;

aging the gel to produce a porous glass; and

heat treating the porous glass to form the glass substrate as a generally non-porous, consolidated glass.

3. The method according to claim 1, wherein the step of forming further comprises:

providing a precursor solution of tetraethylorthosilicate in ethanol;

partially hydrolyzing the precursor solution with water containing approximately 1-% hydrochloric acid at room temperature for about one hour to produce a partially hydrolyzed solution;

casting the partially hydrolyzed solution in a casting mold;

aging the partially hydrolyzed solution to form a gel;

further aging the gel to produce a porous glass; and

heat treating the porous glass to form the glass substrate as a generally non-porous, consolidated glass.

4. The method according to claim 3, wherein the step of further aging the gel is carried out for at least one week.

5. The method according to claim 1, further comprising the steps of:

preparing the solution from a metal alkoxide, an amount of water and a solvent;

causing a sol-to-gel transition of the solution to form a gel;

aging the gel to produce a porous glass;

embossing the plurality of light shaping structures onto the gel as the step of recording; and

heat treating the porous glass to form the glass substrate as a generally non-porous, consolidated glass.

6. The method according to claim 1, further comprising the steps of:

preparing the solution from a metal alkoxide, an amount of water and a solvent;

providing the diffuser submaster in a mold cavity;

adding the solution to the mold cavity so that the solution contacts the plurality of light shaping structures on the diffuser master;

causing a sol-to-gel transition of the solution to form a gel;

aging the gel to produce a porous glass and to cast the plurality of light shaping structures onto the porous glass as the step of recording; and

heat treating the porous glass to form the glass substrate as a generally non-porous, consolidated glass.

7. The method according to claim 1, further comprising the steps of:

providing a base substrate;

preparing the solution from a metal alkoxide, an amount of water and a solvent;

coating a portion of the base substrate with a film layer of the solution;

causing a sol-to-gel transition of the film layer to form a gel;

aging the gel to produce a porous glass;

pressing the diffuser sub-master against the film layer during the step of aging to emboss the plurality of light shaping structures onto the film layer as the step of recording; and

heat treating the porous glass to form the glass substrate as a generally non-porous, consolidated glass layer on the base substrate.

8. The method according to claim 7, wherein the step of providing further comprises providing a base substrate of a glass material.

9. The method according to claim 1, further comprising the steps of:

providing a base substrate;

preparing the solution from a metal alkoxide, an amount of water and a solvent;

coating at least one surface of the base substrate with a film layer of the solution;

causing a sol-to-gel transition of the film layer to form a gel;

heating the gel to a temperature of between about 70°

C. and about 120°

C. for between about 4 and 7 hours;

aging the gel to produce a porous glass;

pressing the diffuser sub-master against the film layer during the step of aging to emboss the plurality of light shaping structures onto the film layer as the step of recording;

heat treating the porous glass to form the glass substrate as a generally non-porous, consolidated glass layer on the base substrate.

10. The method according to claim 9, further comprising the step of:

simultaneously performing the steps of pressing and heating during the step of aging.

11. The method according to claim 1, further comprising the steps of:

preparing the solution from a metal alkoxide, an amount of water and a solvent;

causing a sol-to-gel transition of the solution to form a gel;

aging the gel to produce a porous glass; and

heat treating the porous glass at a temperature of between about 1000°

C. and about 1050°

C. to form the glass substrate as a generally non-porous, consolidated, sintered glass.

12. The method according to claim 1, further comprising the steps of:

recording the plurality of light shaping structures on at least an entrance surface of the glass substrate; and

forming a curved surface as a three dimensional lens on an exit surface of the glass substrate.

20. A surface light shaping diffuser formed by the process of claim 1.

13. A method of making a surface light shaping diffuser, the method comprising the steps of:

providing a diffuser submaster of a relatively soft flexible rubber material with at least a first surface and having a plurality of light shaping structures carried on the first surface;

preparing a sol-gel solution from a metal alkoxide, an amount of water and a solvent;

causing a sol-to-gel transition of the sol-gel solution to form a gel;

aging the gel to produce a porous glass;

pressing the first surface of the diffuser submaster into contact with the gel during the step of aging to record the plurality of light shaping structures onto a surface of the porous glass;

separating the submaster diffuser from the porous glass; and

heat treating the porous glass at a temperature greater than or equal to approximately 1000°

C. to form a generally non-porous and consolidated monolithic glass substrate.

21. A surface light shaping diffuser formed by the process of claim 13.

14. A method of making a surface light shaping diffuser, the method comprising the steps of:

providing a diffuser submaster of a relatively soft flexible rubber material with at least a first surface and having a plurality of light shaping structures carried on the first surface;

preparing a sol-gel solution from a metal alkoxide, an amount of water and a solvent;

coating a film layer of the sol-gel solution onto a base substrate;

causing a sol-to-gel transition of the film layer to form a gel;

aging the film layer to produce a porous glass layer;

pressing the first surface of the diffuser submaster into contact with the film layer during the step of aging to record the plurality of light shaping structures onto the porous glass film layer;

separating the submaster diffuser from the porous glass layer; and

heat treating the porous glass layer at a temperature greater than or equal to approximately 1000°

C. to form a generally non-porous and consolidated monolithic glass layer on the base substrate.

15. The method according to claim 14, wherein the step of aging further comprises the step of:

heating the film layer to a temperature of between about 70°

C. and about 120°

C.

16. The method according to claim 14, wherein the step of aging further comprises the steps of:

heating the film layer to a temperature of between about 70°

C. and about 120°

C.; and

simultaneously performing the step of pressing.

22. A surface light shaping diffuser formed by the process of claim 14.

17. A method of making a surface light shaping diffuser, the method comprising the steps of:

providing a casting mold having a diffuser submaster surface on at least a portion of an interior surface of the mold, wherein the diffuser submaster surface is of a relatively soft flexible rubber material having a plurality of light shaping structures carried thereon;

preparing a sol-gel solution from a metal alkoxide, an amount of water and a solvent;

inserting the sol-gel solution into the casting mold so that the plurality of light shaping structures contact the sol-gel solution;

causing a sol-to-gel transition of the sol-gel solution to form a gel;

aging the film layer to produce a porous glass having the plurality of light shaping structures recorded onto a surface of the porous glass; and

heat treating the porous glass at a temperature greater than or equal to approximately 1000°

C. to form a generally non-porous and consolidated monolithic glass substrate.

18. The method according to claim 17, wherein the step of providing further comprises the steps of:

providing a mold insert as the diffuser submaster surface; and

placing the mold insert into the casting mold.

19. The method according to claim 17, wherein the step of providing further comprises the step of:

providing a casting mold formed from the relatively soft flexible rubber material wherein the plurality of light shaping structures are integrally carried on the interior surface of the mold.

23. A surface light shaping diffuser formed by the process of claim 17.