JP2002514776A - How to make an optical master using incoherent light - Google Patents

Abstract

(57) Abstract: An improved method for making a diffuser master having an irregularly distributed pattern that is preferred for making light diffusers of various sizes inexpensive. The method uses a non-interfering light source (26) through an optical element and is used to expose a photoresist (24) coated on a preferred substrate 25 through a mask pattern (23).

Description

DETAILED DESCRIPTION OF THE INVENTION

BACKGROUND OF THE INVENTION

(1. Field of the Invention)

[0003] The present invention is directed to an improved, faster, and more reliable method for creating irregular pattern holes in a master suitable for making light molded diffusers and similar optical components. It is.

(2. Examination of Related Technology)

Hitherto, interference lasers have been used to make optical products such as light molded diffusers. As shown in FIG. 1, a photosensitive medium 4 such as a photoresist is recorded by exposure to interference (laser) light 1 applied from a krypton laser through a spatial filter 2 and a diffuser 3. The diffuser 3 is a diffuser, holographic, lenticular or acetate diffuser or frosted glass prerecorded in the recording setup of FIG.

A preferred method and apparatus for making such a diffuser is described in US Pat. No. 5,365,354 “Grein-type diffuser based on volume holographic material”, US Pat. No. 5,534,386, owned by the assignee of the present invention. Nos. 5,387,898, and 5,059,939, entitled "Homogeneizers and holographic diffusers made with coherent light" and U.S. Pat. No. 5,609,939, "Viewing screens made with coherent light". A method for recording an optical product, such as a reproduction of an optical product. Each of these U.S. patents is provided as background and known examples of the present invention. U.S. patent application Ser. No. 08 / 595,307 "LCD with light source distribution and shaping device" and U.S. patent application Ser. No. 08 / 601,133 "Liquid crystal with collimated background and non-Lambertian diffuser" Display System ", US Patent Application 08/61
8,539 "Method of manufacturing a liquid crystal display system", US patent application Ser. No. 08 / 800,872.
No. "Method for producing replicas and compositions for use therewith", and US patent application Ser.
There is 2,586 "How to make a duplicate while preserving the master". All of these U.S. patent applications are owned by the assignee of the present invention and are provided by way of background and known examples of the present invention, but the invention is not limited thereto.

[0007] The methods shown in these patents provide both internal and surface structures, called "speckles," which diffuse light in a more efficient, uniform and controlled manner than conventional methods can do. It can be made in the medium 4. The size and shape of the speckle recorded in the photosensitive medium can be controlled as well described in the above patents,
Therefore, the angle of the output light from the diffuser can be controlled after development. Diffusers made by the method of the above patent are extremely useful as viewing screens and homogenizers with myriad uses.

For mass production, the surface structure remaining in the photosensitive medium 4 after processing is utilized. After exposing the photosensitive medium for a preferred time, it is processed to form a master. A first generation submaster or replica of epoxy or other synthetic resin is created from the master by adding epoxy to the surface of the master, spreading it evenly on the master, and releasing the epoxy from the master after the epoxy has cured. Sub-masters of successive generations are made from previous generations of sub-masters by the above process. Each successive generation of submasters causes a change (usually a decrease) in the aspect ratio of the features of the surface structure due to shrinkage.

The above-mentioned known examples have a number of disadvantages. First, the overall size of the diffuser that can be created is limited by the intensity of the laser used and the sensitivity of the photosensitive medium. Second, the prior art requires an interference light source that produces a very high energy density on the order of 2.7 Joules / cm ² to obtain the desired exposure. As a result, as shown in FIG. 2, it was conceived that a large seamless master was formed by connecting a large number of small sub-masters to each other. It was extremely difficult to do.

[0010] Furthermore, when making a large master diffuser, the holes in the corner areas become misaligned with respect to the center area, resulting in an undesirable non-uniform pattern. Finally, conventional systems are extremely sensitive to vibration and motion due to the slow response of the photoresist to light and the need to physically separate the light source from the diffuser and photosensitive medium, as shown in FIG. .
Even a very slight vibration causes a phase change in the interference light source, causing undesirable aberrations in the master. The size of this aberration may exceed the size of the speckle, making the master unusable. Due to vibrations and other disadvantages of the above recording method, it is difficult or impossible to record speckles of extremely small size. For example, to create a diffuser having an extremely wide output in the horizontal direction and an extremely narrow output in the vertical direction, the speckle recorded in the photosensitive medium needs to be extremely small in the horizontal direction (and large in the vertical direction). (The light output light distribution from the diffuser is inversely proportional to the speckle size and the light distribution inside the diffuser). For example, to triple the horizontal output angle, the speckle size must be reduced to one third.

[0011] Furthermore, it is conventionally necessary to make separate masters for diffusers with special angular outputs, which requires a large library of masters with different angular outputs. For example, different masters are desired to achieve 10 ° × 10 ° circular output, 10 ° × 15 ° elliptical output, and the like. To make these masters, it is necessary to use the recording setup shown in FIG. As mentioned above, this recording process is slow and susceptible to vibration and other effective impairment factors.

It is very desirable to have a method for producing a large and inexpensive seamless master without being affected by vibration.

(Summary and Object of the Invention)

A primary object of the present invention is to provide an improved method of making a master having a plurality of randomly distributed speckles suitable for making a light-shaped diffuser.
It is another object of the present invention to provide a simple and reliable method for creating a large seamless master. It is another object of the present invention to provide a method for inexpensively, completely and uniformly reshaping a large-sized light shaping diffuser without sensitivity to vibration and movement. Yet another object of the present invention is to provide a method for making a master, wherein the angular spread of light output from the light-shaping diffuser is desired without using many successive generations of submasters. To get.

In the present invention, the above object can be achieved by a method using non-interfering light to record a desired speckle pattern in a photosensitive medium. In the present invention, the film is exposed to one actual speckle pattern or one produced by a computer. The film is exposed by a standard interference laser setup as shown in FIG. 1 replacing the film with a photosensitive medium 4, or a computer driven imagesetter driven by a number of random sequences that expose the film randomly with dots. After exposure, the film is developed, placed in contact with a photosensitive medium, such as a standard photoresist, and exposed to non-interfering light so that the speckle pattern in the film is exposed on the photosensitive medium. The speckle structure in the photosensitive medium is used as a master to create a sequential submaster and final diffuser product.

In the present invention, a film is exposed in an image setter corresponding to a pseudo-random sequence obtained from a maximum length shift register realized by hardware or software. This pseudo-random sequence is used by the raster image processor of the imagesetter to control the irregular distribution or emission characteristics of the laser or "dots" of the film. The film exposed dots are made to resemble the speckles recorded in the standard setup of FIG.

Also, in the present invention, a highly sensitive millimask film can be exposed in a standard interference laser setup where the millimask film is replaced by a normal photosensitive medium. In this case, the speckles are recorded in the film in a short time, are less sensitive to vibration and have a higher resolution.

If a particularly small feature size in the film is desired, for example, if a diffuser having a large angular output is desired, the film obtained by any of the above methods using standard optical reduction techniques. Reduce (or enlarge). This reduced or enlarged film can then be contact copied onto a photosensitive medium, such as a photoresist, or used in a stepper to obtain a second film with smaller sized dots, and then used in a non-interfering light, such as a photoresist. Used in a stepper to contact-copy on top of or to expose photoresist in the stepper.

In the present invention, the drum in the deformed imagesetter is further covered with a photosensitive medium such as a photoresist and exposed by an imagesetter laser, thereby completely eliminating the need for a film. The unexposed photoresist on the drum is removed by standard etching techniques, and then the drum itself is etched with an irregular dot pattern. This drum is then preferably used to emboss or stamp an epoxy or other layer on a plastic or other sheet in a continuous process.

In the present invention, a collimated UV, excimer or electron beam source is used to expose a photoresist sandwiched on chrome on glass using a pseudo-random dot pattern. The unexposed photoresist is etched away and then the chrome is etched away to create a dot pattern in the chrome.

The diffuser produced by the method of the present invention can be large enough to be used for front and rear projection screens, fluorescent screens, highway and advertising signs, and the like. The present invention provides an inexpensive, fast turnaround (approximately 48 hours from the original concept of mastering), the use of inexpensive non-interfering light sources, such as standard arc lamps, for exposing photoresist material, and vibration and movement. A large scale diffuser is obtained that is insensitive, perfectly uniform and resilient, and a large elliptical or circular diffuser that produces an angular output of any shape is obtained, with a linear or circular gradient, or a variable direction It has the ability to create unique diffuser patterns that exhibit elliptical characteristics. Still other advantages of the present invention will be readily apparent to those skilled in the art.

Other objects and features of the present invention will become apparent from the following description of the drawings. However, the following description and preferred embodiments of the invention are not limiting.
Naturally, the present invention can be variously changed and increased without departing from the spirit of the present invention.

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION

(A. Film Recording in Imagesetter )

The preferred embodiment of the present invention utilizes an imagesetter to create a high resolution master for forming the master. Imagesetters are known in the photographic art to use their capabilities to form high resolution masks on photographic film, and are typically used for high resolution color printing. Preferred imagesetters for use in the present invention are Agfa and Hellinetronic.
nic).

In general, an imagesetter is a supply of unexposed film, a recording surface support or holder, such as a drum, to support the material during exposure, recording based on commands from a dedicated laser image processor or “RIP”. An image exposure system for forming an image to be formed. Image exposure systems use one or more lasers or other light sources. For example, a film such as a Kodak 2000 series film is scanned by a beam and exposed to form a latent image on the material.
The film is then removed from the imagesetter for the next process.

FIG. 3 shows the imagesetter 10. The film 12 is supported by a capstan roller, a flat plate, a cylindrical drum platen and other supporting surfaces 14 as shown in FIG. A scanning exposure system 16 for film exposure includes a light or light source 18 such as a laser mounted at a predetermined distance from the support surface 14 and an optical system for focusing a light beam 22 from the light source 18. And a beam deflecting device for beam scanning across the film 12. The scanning exposure system is moved by a precision linear drive along the line CC of the drum having the support surface 14, while the film 12 is held in place. As the scanning exposure system moves, a laser or other light source is fired to expose an exposed area of the film in response to commands created by the RIP.

In the present invention, the basic characteristics to be recorded on the film are indicated as “dots”, which need not be circular but may be elliptical, rectangular or any other shape. Large features such as elliptical structures can be created by combining multiple adjacent dots. The dots correspond to "speckle" in the prior art and are combined as needed to achieve with a diffuser having the desired angular output. Whether or not a dot located at a particular position on the master is defined by a pseudo-random sequence is described below.

( Generation of a Preferable Pattern for Diffused Light )

FIG. 4A shows a regular, periodic diffraction grating with rectangular holes. FIG. 4B shows a diffraction pattern when the diffraction grating is illuminated with white light. FIG. 5A shows a regular, periodic diffraction grating with circular holes. FIG. 5B shows the result of the diffraction pattern. Because these diffraction patterns are regularly repeating, each light wave shows a fixed phase relationship to the others. Thus, there are certain directions in which light waves interfere constructively and destructively, resulting in a diffraction pattern. The purpose of making a diffuser is to prevent the generation of such diffraction patterns and to evenly diffuse the light output.

FIG. 6A shows an irregular array of rectangular holes. FIG. 6B shows the resulting white light diffraction pattern. FIG. 7A shows an irregular array of circular holes. FIG. 7B shows the resulting white light diffraction pattern and a series of concentric rings surrounding the white center desk. As shown in the figure, an irregular array of holes produces a more diffuse diffraction pattern than the pattern output from a periodic array. However, the diffusion pattern still exists. This pattern is due to the use of a somewhat coherent white light source. If a completely incoherent light source is used, the diffusion pattern will be uniformly diffused. Alternatively, if the holes are blurred to remove sharp edges, the pattern will be erased. Therefore, the masks generally desired to make the diffuser preferably have an irregular disorder without sharp edges.
) It has characteristics.

Such a pattern can be obtained from an imagesetter by creating a mask code based on a pseudo-random sequence of sufficient length so as not to repeat itself over an area equal to the size of the mask. The pseudo-random sequence is created by a maximum length shift register that can be executed by software or hardware. A functional diagram of the hardware implementation is shown in FIG. 8, which includes a shift register 80 and an OR gate 90 connected in a feedback manner. Preferably, making a maximum length shift register by software, it is adapted to be used Stock imagesetter RIP _S instead of hardware bespoke. Because hardware is maximally available for special applications, and is therefore generally fast, hardware implementation is preferred where speed is paramount. One example of a preferred source code for creating a pseudo-random sequence in a C word is as follows.

Here, #section mask 0 × 80000057

Unsigned long static shift register = 1

Void seed LFSR (long unsigned seed) ｛young (seed == 0) / * void void * / seed = 1;

Shift register = seed;

Int deformation LFSR (void)

{Your (shift register and 0 × 00000001)} shift register = (shift register @ mask) >> 1) | 0 × 8000000;

Return 1;

｝ Or ｛shift register >> = 1 = 1;

Return 0;

( Characterization of Light Forming )

In general, the feature size and shape determine the angular output pattern of light from the light shaping diffuser. The angular distribution of light is controlled by the Fresnel diffraction equation. The curvature r of a given circular hole and the angular spread θ corresponding to the wavelength λ of light are

Sin θ = 1.22 λ / 2r

Is as follows.

Elliptical features with aligned axes are often used for shaping the output pattern of a light shaping diffuser. An elliptical feature with a horizontal principal axis produces an output pattern that is vertically elongated, ie rotated 90 ° with respect to the principal axis of the elliptical diffuser feature. Speckle recording methods for producing the desired angular distribution of light from the light-shaping diffuser are described in detail in the U.S. Patents referenced in the Related Art section.

( Determination of Number of Features )

After calculating the size and shape of the holes, it is necessary to determine how to create these features from the collection of dots. Each of the basic features is indicated by one binary bit.

The basic feature size is determined by several factors. First, the programming language that describes the printing process determines the display accuracy of the print command. The preferred embodiment uses the PostScript language. One PostScript point is 1/7 of an inch
As a result of 2, one inch is 25,400 microns and the Postscript point is 352,78 microns. 0.0001 or 0.035 inch PostScript can be calculated. This level of accuracy is sufficient for optical applications of the present invention. Other print programming languages are used to indicate features with sufficient accuracy, as will be apparent to those skilled in the art. Further, in any optical system, the feature size is limited by diffraction and lens aberrations as will be apparent to those skilled in the art.

Some features need to be superimposed to prevent the appearance of periodic features in the space between features. A uniform overlap of 0.75 in the space between features (on the order of √2) is sufficient to ensure sufficient overlap to prevent uniform areas that do not contain features.

The number of features for a given area master is defined as follows.

Feature density × film area = number of features

A pseudorandom sequence of sufficient length that features will be randomly distributed is defined as follows.

In (number of features) / In 2 = bit

Where bits are the number of bits in the maximum length shift register required to create a random sequence of sufficient size to cover the entire area of the film to be exposed without repetition. In general, a 128 bit long register is sufficient for any use.

( Creation of Master )

After exposing the film as described above, the film can be developed to negative by standard development techniques.

As shown in FIG. 9, the negative acts as the mask 23 in a standard contact copying process by placing the mask 23 on a photoresist or similar photosensitive medium. The photoresist 24 is disposed on a substrate as a photolithographic plate 25 made of glass, but a preferred plastic material may be used. This mask 23 is fixed on a photolithographic plate 25 as shown in FIG. 9 by a clamp, a cover sheet, or a vacuum action.

As shown in FIG. 9, the combination of the mask and the photoresist plate is exposed with the non-interfering light source 26, and the mask pattern is exposed on the photoresist. Preferably, the light source has an output of 300
A non-parallel UV light source with a wavelength of ~ 500 watts and a wavelength range of 365-400 nm. This light source shines and diffuses uniformly and is the same size as the size of the sheet film to be exposed. A good example of a diffuse light source of sufficient size is a large fluorescent light. For uniform scanning over the surface to be exposed, a smaller light source is used.

The diffuse light source blurs the boundary between the light and dark portions. The boundaries are preferably blurred because features with very sharp edges produce non-diffused light with a diffraction pattern such as the blue or ring pattern shown in FIG. 7B. As a variant, there are several other ways to obtain a blurred feature if a favorable diffuse light source is not available. One is to create successive generations of masters from the first generation master to eliminate the sharp edges of features. A variation is to adjust the imagesetter so that it is slightly out of focus. Another possibility of blurring feature edges is through linear chemical processes of the film and / or photoresist. The linear process involves changing the intensity of development to obtain a linear change between black and white.

(B. Recording Film in Standard Laser Recording Setup )

In a second embodiment using a film, the master of the present invention uses a recording setup as shown in FIG. 10 and replaces the photoresist / glass plate of FIG. 1 on a semiconductor flat film 31 like an 8E56 mm mask. Make by recording speckles. The film is exposed by interference light from laser 28 passing through diffuser 30.
Since the film 31 has high photosensitivity, it is desired to expose the film 31 for several seconds, unlike the case of a photoresist. The resulting film is used as a mask in a standard contact recording process as shown in FIG. 9 to record features on a photoresist plate by exposing features to non-coherent ultraviolet radiation in the manner described above. The millimask film is in physical contact with the photoresist by a vacuum or clamping mechanism so that the exposure time can be as long as necessary without causing stability problems in conventional methods. Accordingly, deep aspect ratio structures can be recorded in photoresist using extremely long exposure times.

(C. Reduction of Film )

The size between the film negative and the photoresist coated plate is always set to 1: 1 using the contact copying shown in the above sections A and B. It is difficult to obtain feature sizes below about 5 microns using simple contact coating techniques. For dots of 4 microns or less, a light reduction technique is used as shown in FIG. First, the exposed film 32 is made using the techniques described above or other preferred techniques. The film is then developed and the size of the dot record on the film is reduced by a standard photo reduction camera 34. The film is then contact copied onto a photoresist or the like as shown in FIG. Further, the reduced (or enlarged) second film is exposed again using the reduced film as a mask in the stepper shown in FIG. The second film is then contact-copied to a photoresist or the like. Further, in a modified example, a stepper having a first or second film as a mask may be used, and this film may be stepped along the separated points of the photoresist in each step to expose the photoresist. FIG.
As shown in FIG. 2, the stepper includes an ultraviolet light source 36 having a shutter, an enlarging mask 37 which generally increases the actual size by a factor of 5, a 1/5 reducing lens 38, and a precision XY movable stage 40. The photoresist 39 is placed on a stage 40, the stage 40 is moved, the shutter is opened, and a selected area of the photoresist in the "step" is exposed through a mask 37 with UV light.

The size of the holes can be changed optically to determine the angular spread of light output from the diffuser without having to record a new master to change the angular spread of the diffuser. As the feature size decreases, the angular spread of the output increases proportionally. For example, if the feature size is reduced to one tenth, the angle will be increased ten times. Therefore, as shown in FIG. 13, when the circular angle output of the film which is not reduced is 9 °, the angle output increases to 90 ° by one-tenth reduction. In this case, the angular spread of the master can be adjusted by optical reduction or enlargement.

As shown in FIG. 14, the shape of the features can be changed by using anamorphic lenses that distort the horizontal or vertical magnification in the stepper. The preferred optics technique allows the size and shape of the features to be obtained from a single mask, thus creating a custom light-shaped diffuser in which a change in the recording setup of FIG. The process can be very simple.

(D. Etching of Metal Drum without Filter )

In the third non-film embodiment, instead of recording the features on a film fixed to the surface of the drum, the dot pattern display speckle was directly applied to the surface of a metal drum coated with a layer of photoresist. Use a deformed imagesetter for recording. As shown in FIG. 15, the photoresist-coated drum 41 is exposed by a laser 42 that scans all the drums in the imagesetter 43. The drum 41 is then removed from the imagesetter 43 and processed by standard etching techniques.
The unexposed photoresist on the drum surface is first etched using a photoresist developer using standard materials and processes. This unexposed surface is then further etched with nitric acid, causing the metal to etch the pattern.

The photoresist is then removed using a solvent. The drum 44 obtained as shown in FIG. 16 is a master that can be used to emboss a seamless light forming drum of unlimited length. The diffuser can be embossed into an epoxy 45 or other plastic resin attached to a plastic substrate 46. A drum 45 is wrapped with a substrate 45 coated with an epoxy 41 to obtain an imprint of the diffuser and exposed with a UV light source 47 to cure the epoxy. The light source 47 is a non-parallel UV light source having an output of 300 to 500 watts and a wavelength range of 365 to 400 nm.

(E. Excimer Laser or Electron Beam Recording )

A small feature size can be obtained without using a UV excimer laser or an electron beam as a light source and reducing the size of a photograph. When a UV excimer laser is used, a feature size as small as about 7 microns can be obtained. As a variant, smaller dot sizes of 1 micron or less can be obtained using an electron beam. As shown in FIG. 17, the process uses a glass sheet 50 on which a first layer 49 of chrome is deposited and then the first layer 4 of chrome is deposited.
Depositing a first layer 48 of photoresist on top of the photoresist. Computer-generated pseudo-random features can be recorded in photoresist using a UV excimer laser source 51 and / or an electron beam source. The pseudo-random features are created in a maximum length shift register as described above that is used to modulate the laser source 51 when the photoresist 48 is exposed. The unexposed photoresist is then etched away using a standard process and further etched with nitric acid or the like to etch away the chrome metal layer. The remaining photoresist is then washed away with a solvent. Although the resulting dot size is much smaller than with the film process described above, excimer lasers and electron beams are much more expensive.

Although the preferred embodiments of the present invention have been described above, the present invention should not be limited to these detailed descriptions, specific examples, and preferred embodiments. Of course, the present invention can be variously increased, decreased, or changed without departing from the spirit of the present invention.

Many other changes can be made as described above without departing from the spirit of the invention. The scope of this change will become apparent from the description of the claims.

[Brief description of the drawings]

The clear concepts, benefits and features of the present invention and the operation of the arrangement of the exemplary mechanism according to the present invention will be further clarified with reference to the embodiments. The embodiments illustrated in the accompanying drawings are not limiting and form part of the detailed description.

FIG. 1 is an explanatory diagram of a conventional recording method for a photosensitive medium having speckle.

FIG. 2 is an explanatory view of a conventional method for making a large master from a large number of submasters.

FIG. 3 is an illustration of a side view of a preferred imagesetter for performing the method of the present invention.

FIG. 4A is an explanatory diagram of a regular periodic grid of rectangular holes.

FIG. 4B is an explanatory diagram of a diffraction pattern obtained by illuminating the grating with white light.

FIG. 5A is an explanatory view of a regular periodic lattice of circular holes.

FIG. 5B is an explanatory view of a diffraction pattern obtained by illuminating the diffraction pattern of FIG. 5A with white light.

FIG. 6A is an explanatory diagram of an irregular row of rectangular holes.

FIG. 6B is an explanatory diagram of the obtained white light diffraction pattern.

FIG. 7A is an explanatory view of an irregular row of circular holes.

FIG. 7B is an illustration of a white light diffraction pattern having a series of concentric rings around a white center plate.

FIG. 8 is a functional diagram of a preferred apparatus for producing a pseudo-random sequence of the present invention.

FIG. 9 is an explanatory diagram of contact copying of a film on a photoresist.

FIG. 10 is an explanatory diagram of a standard laser recording setup using a millimask film.

FIG. 11 is an explanatory diagram of film reduction.

FIG. 12 is an explanatory diagram of a stepper mask.

FIG. 13 is an explanatory diagram of an angle spectrum output enlarged from 9 ° to 90 ° by reducing the dot size by 1/10.

FIG. 14 is an explanatory diagram of a recording setup for changing a shape of an angular output using an anamorphic lens in a stepper.

FIG. 15 is an explanatory diagram of a filmless recording setup using a photoresist on a metal drum.

FIG. 16 is an explanatory view of a continuous or discontinuous drum press.

FIG. 17 is an illustration of an electron beam or excimer laser recording setup.

[Procedure for Amendment] Submission of translation of Article 19 Amendment of the Patent Cooperation Treaty

[Submission date] October 2, 1999 (1999.10.2)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claims

[Correction method] Change

[Correction contents]

[Claims]

25. The method according to claim 18, wherein said photosensitive medium is a photoresist coated drum.

[Procedural Amendment] Submission of translation of Article 34 Amendment of the Patent Cooperation Treaty

[Submission date] April 11, 2000 (2000.4.11)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claims

[Correction method] Change

[Correction contents]

[Claims]

──────────────────────────────────────────────────の Continuation of front page (81) Designated country EP (AT, BE, CH, CY, DE, DK, ES, FI, FR, GB, GR, IE, IT, LU, MC, NL, PT, SE ), JP, KR (72) Inventor Coupick Stephen A. U.S.A. 90503 Torrance Gamet 2 3725 United States California 90505 Torrance Via El Sereno 4629 F-term (reference) 2H042 BA03 BA06 BA15 BA21 2H049 CA05 CA16 CA28 2H097 AA16 AB08 BA06 CA06 CA13 CA16 CA17 GA11 GA33 JA03 LA17 2K008 BB03 FF17 GG05 HH02 HH26

Claims (29)

[Claims] 1. Exposing a photographic film with a laser beam modulated by a speckle pattern, developing the photographic film, disposing the photographic film adjacent to a photosensitive medium, and exposing the photographic film through the photographic film. A method for producing a master optical diffuser comprising a step of exposing a conductive medium with non-interfering light. 2. The method according to claim 1, wherein said photosensitive medium is a photoresist. 3. The method of claim 1 wherein said photographic film is a Kodak 2000 8E56 millimask. 4. The method of claim 1 wherein said laser light is from a krypton laser. 5. The method of claim 1, wherein the incoherent light is a UV arc lamp. 6. The method of claim 1, wherein said speckle pattern is based on a pseudo-random sequence. 7. A pseudo-random pattern having a feature is formed, the pseudo-random pattern having the feature is recorded in a mask, the photosensitive medium is covered with the mask, and the masked photosensitive medium is exposed by a non-interfering light source. A method for producing a master, comprising transferring a random pattern having the above characteristics to the photosensitive medium. 8. A film is placed on a print drum of an imagesetter, and the film is exposed with a light beam source inside the imagesetter to form a mask of pseudorandom size. The film is removed and the film is removed. Developing the negative, arranging the negative adjacent to the photoresist, exposing the photoresist by non-interfering light through the film, and developing the photoresist. 9. The method of claim 7, further comprising the step of moving said incoherent light source between exposure of said negative and photoresist. 10. The method of claim 7, further comprising the step of reducing said negative in a high resolution reducer. 11. The method of claim 7, wherein said reduced negative is used as a stepper mask. 12. The method of claim 7, wherein said incoherent light source is a diffuse light source. 13. A drum disposed on a drum of an imagesetter, exposing the photoresist with a light beam source in the imagesetter, removing the unexposed portions of the photoresist by etching, and exposing the photoresist by the etched photoresist. A method for producing a master, comprising the steps of: etching the photoresist and washing out the remaining photoresist. 14. A millimask film is exposed by an interfering light beam source passing through a spatial filter and a diffuser, developing the film, placing the developed film on a photoresist, and passing the photoresist through the film. Exposing the photoresist to non-interfering light and developing the photoresist. 15. The method of claim 11, further comprising reducing the film using a high-resolution reducer. 16. The method of claim 11, wherein said light beam comprises a UV excimer laser. 17. Coating the glass with a layer of chrome, coating the layer of chrome with a photosensitive medium, making a computer generated pseudo-random size mask, exposing the photoresist with a light source through the computer generated mask. Etching the unexposed portion of the photoresist, etching the exposed metal with the etched photoresist, and washing out the remaining photoresist. 18. The method of claim 15, further comprising using the etched metal in one of an injection molding process and a stamping operation. 19. The method according to claim 15, wherein the light source is one of a UV excimer and an electron beam light source. 20. A pseudo-random pattern having features, the pseudo-random pattern is recorded on a mask by an imagesetter, the photosensitive medium is covered by the mask, and the coated photosensitive medium is exposed by a non-interfering light source. Transferring a random pattern of features to the photosensitive medium, and etching the photosensitive medium to realize the random pattern of the features in the photosensitive medium. A method for producing a master diffuser using an imagesetter. 21. The method of claim 18, wherein said pseudorandom pattern of features is formed by a maximum length shift register. 22. The method according to claim 18, wherein said mask is a photographic film. 23. The method according to claim 18, wherein said photosensitive medium is a photoresist. 24. The method of claim 18, wherein said incoherent light source is an arc lamp. 25. The method according to claim 1, wherein the incoherent light source is a UV light source.
8. The method according to 8. 26. The method of claim 18, wherein said incoherent light source is a diffuse light source. 27. The method of claim 18, wherein said imagesetter is an excimer laser. 28. The method of claim 18, wherein said imagesetter is an electron beam. 29. The method of claim 18, wherein said photosensitive medium is a photoresist coated drum.