KR20070030925A - Apparatus and method for making flexible waveguide substrates for use with light based touch screens - Google Patents

Abstract

Flexible optical waveguide substrates are provided that can be used with a touch screen display. Waveguide substrates include a flexible substrate. A first optical layer having a first refractive index is formed on the flexible substrate. A second optical layer is then formed on the first optical layer and patterned to form a plurality of optical elements and waveguides, respectively. The second optical layer also has a second refractive index that is greater than the first refractive index. Finally, the third optical layer is formed on the second optical layer. The third optical layer has a third refractive index that is less than the second refractive index. Thus, the high N second layer is sandwiched between the lower N first and third layers, creating an internal reflective surface for each portion of the high N and low N material contact. Thus, the substrate and the first, second and third optical layers form flexible waveguide substrates.

Waveguides, Optical Layers, Flexible Substrates

Description

FIELD OF THE INVENTION A method and apparatus for manufacturing a flexible waveguide substrate for use with an optical based touch screen.

Background of the Invention

1. Field of invention

FIELD OF THE INVENTION The present invention generally relates to light-based touch screen displays, and more particularly, to methods and apparatus for manufacturing optical element waveguides that can be used with a touch screen display.

2. Disclosure of related technology

User input devices for a data processing system can take many forms. Two types involved are a touch screen and a pen base screen. If having a touch screen or a pen based screen, the user may enter data by touching the display screen with either a finger or an input device such as a stylus or pen.

One conventional way of providing a touch or pen based input system is to cover a resistive or capacitive film over a display screen. This method has many problems. First, the film subsides and obscures the field of view of the underlying display. To compensate for this, the brightness of the display screen is often increased. However, for most portable devices such as mobile phones, PDAs, and laptop computers, high brightness screens are not typically provided. If a high brightness screen is provided, the added brightness requires additional power while reducing the battery life of the device. The membranes are also easily damaged. These films are therefore not ideal for use via a pen or stylus input device. The movement of the pen or stylus may damage or destroy the thin film. This is particularly accurate if the user records with a large amount of force. In addition, the cost of producing the membrane increases rapidly with the size of the screen. With a wide screen, the production cost is usually very large.

Another method of providing a touch or pen based input system is an array of source light emitting diodes (LEDs) along two neighboring XY planes of the input display and a corresponding photodiode along two neighboring XY planes opposite the input display. Is to use an array. Each LED produces a light beam that is directed to the reverse photodiode. When the user touches the display, either with a finger or a pen, an interruption in the light beam is detected by the X and Y photodiodes corresponding to the opposite side of the display. The data input is thus determined by calculating the coordinates of the interrupt detected by the X and Y photodiodes. However, this type of data input display also has many problems. A large number of LEDs and photodiodes are required for typical data input displays. The location of the LEDs and the back light diodes also need to be aligned. The need for a relatively large number and precise alignment of LEDs and photodiodes makes it complicated, expensive and difficult to manufacture such displays.

Another approach involves the use of polymer waveguides that both produce and receive beams of light from a single light source to a single array detector. Such systems tend to be complex and expensive and require alignment between transmit and receive waveguides, optical elements and waveguides. Waveguides are conventionally made using lithographic processes that are difficult and expensive to generate. In addition, the waveguide is typically flat. As a result, the bezel around the display is relatively wide. See, eg, US Pat. No. 5,914,709.

Accordingly, there is a need for a method and apparatus for making an inexpensive, flexible optical waveguide that can be used with a touch screen display.

Summary of the Invention

The present invention relates to a method and apparatus for manufacturing a low cost flexible optical waveguide that can be used with a touch screen display. The apparatus includes a flexible substrate. The first optical layer having the first refractive index is formed on the flexible substrate. The second optical layer is then formed on the first optical layer, patterned to form a plurality of optical elements and waveguides, respectively. The second optical layer also has a second refractive index higher than the first refractive index. Finally, the third optical layer is formed on the second optical layer. The third optical layer has a third refractive index lower than the second refractive index. Thus, the high N second layer is sandwiched between the lower N first and third layers, creating an internal reflective surface wherever the high N and low N materials are contacted. Thus, the substrate and the first, second and third optical layers form a flexible waveguide substrate.

Brief description of the drawings

The invention will be better understood by reference to the following description in connection with the accompanying drawings, together with other advantages of the invention.

1 is a touch screen display device.

2A is a sheet comprising a plurality of flexible waveguide substrates fabricated on the sheet in accordance with one embodiment of the present invention.

FIG. 2B is a substrate of the flexible waveguide cut off the sheet of FIG. 2A. FIG.

FIG. 2C is a perspective view of the flexible waveguide cut off the sheet of FIG. 2A. FIG.

2D is a perspective view of an application of a flexible waveguide substrate around a touch screen display.

3A is a perspective view of another flexible substrate according to another embodiment of the present invention.

3B is a view showing the flexible substrate of FIG. 3A used around the touch screen according to the present invention.

FIG. 3C is a diagram illustrating an improved resolution of the substrate of FIG. 3A.

4A-4C are illustrations of nested waveguide substrates in accordance with the present invention.

Fig. 5 is a flowchart showing manufacturing steps for manufacturing the waveguide substrate of the present invention.

FIG. 6 is a diagram showing the manufacture of a waveguide substrate according to another embodiment of the present invention. FIG.

7A and 7B show another nested waveguide in accordance with the present invention.

In the drawings, like reference numerals refer to like components and elements.

Detailed description of the invention

Referring to FIG. 1, a touch screen data input device according to one embodiment of the present invention is shown. The data input device 10 defines a continuous sheet or “lamina” 12 of light in an empty space adjacent to the touch screen 14. The remina 12 of light is produced by the X and Y input light sources 16 and 18, respectively. Optical position detection device 20, optically coupled to the remina 12 of light, enters data into the input device by determining the location of an interrupt in the remina 12 caused when data is input into the input device. To detect them. The light position detection device 20 includes an X receive array 22, a Y receive array 24, and a processor 26. The X and Y input light sources 16 and 18 and the X and Y receive arrays 22 and 24 are formed by a single waveguide substrate 28 that surrounds the remina 12 and the touch screen 14.

In operation, the user enters data into the device 10 by touching the screen 14 using an input device such as a pen, a stylus or a finger. While touching the screen with the input device, the remina 12 of light in the empty space adjacent to the screen is interrupted. The X receive array 22 and the Y receive array 24 of the light position detection device 20 detect an interrupt. Based on the X and Y coordinates of the interrupt, processor 26 determines the data input to device 10.

Light remina 12 is a substantially uniform luminance according to one embodiment of the invention. The required active range of the photosensitive circuits in the receiving X and Y axis arrays 22 and 24 is thus minimized and high insertion accuracy is maintained. However, in other embodiments, non-uniform remina 12 may be used. In this situation, the lowest luminance region of the remina 12 should be higher than the light activity threshold of the light detection element used by the X and Y axis arrays 22 and 24.

The touch screen 14 can be any data display type in accordance with various embodiments of the present invention. For example, screen 14 may be a PC, workstation, server, mobile computer, laptop computer, POS terminal, personal digital assistant (PDA), mobile phone, any combination thereof, or any device that receives and processes data inputs. May be a display for the user.

The wavelength of the light generated by the X and Y axis light sources 16 and 18 used to produce the remina 12 may also vary in accordance with another embodiment of the present invention. For example, the light may be broadband with an extended wavelength spectral range of 350-1100 nanometers, such as white light from an incandescent light source. Optionally, the input light can be narrowband with a limited spectrum in the range of 2 nanometers. The use of narrowband light enables the filtering of wideband ambient noise light. The use of narrowband light also enables substantial matching of the wavelength of light to the reaction profile of the X-axis light receiving array 22 and the Y-axis light receiving array 24. In another embodiment, uniform, single wavelength light may be used. For example, infrared or IR light, commonly used in wireless or long distance data transmission communications, may be used in this application.

Referring to FIG. 2A, a sheet 30 is shown that includes a plurality of flexible waveguide substrates 28 fabricated on the sheet. According to one embodiment, multiple waveguides 28 are fabricated on a single sheet 30. Individual substrates 28 are made side by side in an elongated strip on the surface of the sheet 30. After the substrate 28 has been fabricated, the sheet 30 is cut to singulate the individual waveguide substrate 28. The sheet 30 may be cut using one of a variety of known techniques using, for example, a knife, saw blade or the like. Details of the fabrication of the waveguide substrate 28 are provided below.

Referring to FIG. 2B, a flexible waveguide substrate 28 is shown cut from the sheet 30. As is clear from the figure, the waveguide substrate 28 includes a plurality of optical elements 32 provided on one side of the substrate 28. According to various embodiments, the optical elements 32 may include lenses, diffraction gratings, filters, Bragg gratings, coupling horns, and the like. Waveguide 34 is optically connected to each optical element 32. The plurality of waveguides 34 are gathered together and run parallel to the longitudinal direction of the substrate 28 in those called waveguide highways 36.

2C is a perspective view of the flexible waveguide substrate 28. In this figure, the optical elements 32 are shown along one side of the substrate 28. Individual waveguides 34, optically connected to the optical elements 32, are shown gathered together along the optical highway 36. The individual waveguides 34 run in the longitudinal direction of the substrate 28 (not shown in the figure).

Referring to FIG. 2D, a perspective view of waveguide substrate 28 around touch screen display 14 of input device 10 is shown. One application of the flexible waveguide substrates 28 is that the waveguide substrates may be configured to provide X and Y input light sources (16, 18 of FIG. 1) and an X and Y receive array (22, 24 of FIG. 1) for the input device 10. It can be easily used to provide. As shown in the figure, the waveguide substrate 28 has optical elements 32 configured to face the center and is provided on the perimeter of the touch screen 14. Thus, optical elements 32 on the X and Y input light source side of the touch screen are used to generate a remina (12 in FIG. 1) of light on the touch screen 14. For the sake of simplicity, individual waveguides 34 are not shown in the figure. Alternatively, optical elements 32 on the X and Y receive array side of display 14 are used to read the data inputs by detecting interrupts at remina 12. The light source 38 provides light to the waveguides (34 of FIG. 2C) connected to the optical elements 32 along the light input side of the touch screen 14. An imaging device 39, such as a MOS device or CCD, is provided adjacent to the waveguides 34 connected to the optical elements 32 along the X and Y receiving surfaces of the touch screen 14.

Referring to FIG. 3A, a multilayer flexible waveguide substrate 28 in accordance with another embodiment of the present invention is shown. In this embodiment, two layers of optical elements 32 are provided along one side of the substrate 28. The optical elements 32a of the first or base layer are provided at spatial intervals. Optical elements 32b of the second layer are provided over the first layer. The optical elements 32b of the second layer are interposed between the optical elements of the first layer. Similar to the embodiment described above, the waveguides 34 of the optical elements 32a and 32b are gathered together in the highway 36 running in the longitudinal direction of the substrate 28.

Referring to FIG. 3B, a diagram illustrating the multilayer flexible substrate of FIG. 3A is shown. In the figure, the lenses 32a of the first layer and the lenses 32b of the second layer are shown around the outer edge of the touch screen 14. An advantage of the two layered structure of FIG. 3A is that it provides a higher resolution compared to a given size of the optical elements 32.

For example, as shown in FIG. 3C, the optical elements 32 each have a width of approximately 1 mm. As such, the distance between intervening optical elements 32 is approximately 1/2 mm. Thus, the touch screen 14 of FIG. 3B has the ability to resolve interrupts of 1/2 mm or more. In contrast, a substrate 28 having only about 1 mm wide monolayer optical elements will have a resolution of only 1 mm. The above dimensions are illustrative and should not be construed as limiting the invention. More precise or coarser resolution can be achieved by using smaller or larger optical elements 32 respectively.

Referring to FIG. 4A, a cross section of a nested waveguide substrate 40 for use with the touch screen 14 is shown in accordance with another embodiment. This embodiment, referred to as a "laid" waveguide, is described in the co-pending parental application described above. In this embodiment, the substrate 40 includes a flat internal reflective surface 42 that allows the waveguide to overlap on the side of the substrate 40. Having a waveguide on the side, the width of the substrate 28 can be reduced. Similar to the other embodiments described above, as described herein, the substrate 40 of FIG. 4A is fabricated and then cut from the sheet (30 of FIG. 2A).

Referring to FIG. 4B, a partial perspective view of nested waveguide 40 provided around touch screen display 14 is shown. As shown, an optical element 32 of the waveguide is provided along the top surface of the waveguide 40 around the outer edge of the touch screen 14. Individual waveguides 34 are superimposed and collected on highway 36 along the side of substrate 40. The light source 38 and the imaging device 39 are shown adjacent to the point where the waveguide 34 ends.

Referring to FIG. 4C, a nested waveguide substrate 40 used with a touch screen 14 according to another embodiment is shown. This embodiment, also referred to as a "stacked" waveguide, is disclosed in the co-pending parent application described above. In this embodiment, the substrate 40 includes a curved internal reflective surface 42 that allows the waveguides to overlap on the side of the substrate 40. Having a waveguide on the side, the width of the substrate 28 can be reduced. Similar to the other embodiments described above, the substrate 40 of FIG. 4C is fabricated and then cut from the sheet 30 as described herein.

Referring to FIG. 5, a flow chart showing manufacturing steps for manufacturing the various embodiments of the waveguide substrates 28, 40, and 90 of the present invention is shown. In an initial step (box 52), a low N optical material is coated onto the sheet 30. In various embodiments, sheet 30 is made of a flexible but mechanically strong material, such as plastic or polycarbonate. The sheet can be transparent or opaque. According to other embodiments, any low N optically transparent material may be used. In the next step (box 54), a high N optically transparent material is coated onto the sheet 30. Optical elements 32 and waveguide 34 are then formed of a high N optically transparent material using optical lithography (box 56). Specifically, a high N layer is masked and patterned to form optical elements 32 and waveguide 34. Another low N optical layer is then formed on the patterned high N optical layer (box 58). The high N material creates an internal reflective surface wherever the high and low N materials come in contact, thus sandwiching between two lower N layers. As a result, optical elements 32 and waveguide 34 are produced. In the final step, the substrates 28 are cut from the sheet 30 (box 60). The substrates of FIGS. 2C and 2D as well as the multilayer flexible substrates of FIGS. 3A-3C may be fabricated using substantially the same technique. After the first layer of optical elements 32 and waveguides 34 are formed, an intermediate layer is formed on the second N layer. The above-described process described in steps 52 to 58 is then repeated.

Referring to FIG. 6, a diagram illustrating the manufacture of waveguide substrates in accordance with another embodiment of the present invention is shown. With this embodiment, the substrates 28 or 40 are made by passing a continuous strip of substrate through a continuous processing station. Initially at station 60, a spool of substrate 62 is provided. The substrate 62 is supplied to the processing station 64 to which the first low N layer is applied. As the substrate rotates around the station 64, a UV curing device 65 cures the first N layer. At station 66, a second high N layer is applied and cured in a similar manner. In station 68, a layer of light register is applied and cured on the second high N layer. The patterning mask is then applied at station 70. The pattern defines optical elements 32 and waveguides 34. Thereafter, portions of the second high N layer that do not form optical elements 32 and waveguides 34 are etched or removed at station 72. A third low N layer is then applied at station 74. The process strip of waveguide substrates 28 or 40 is then spooled in station 80. In one embodiment, the circumference of each processing station is substantially equal to the length of each waveguide substrate 28 or 40. In this way, the spool of substrate can be made of multiple series waveguide substrates 28 or 40, each the same length. The spools are then cut at periodic intervals equal to the length of each substrate to individualize the individual substrates.

7A and 7B, a diagram illustrating another flexible waveguide in accordance with the present invention is shown. The flexible waveguide substrate 90 includes a plurality of optical elements 32 and waveguides 34 aligned with two waveguide highways 36a and 36b and corresponding to the optical elements. Waveguide substrate 90 also includes a fold 92 that separates highways 36a and 36b. Waveguide highways 36a and 36b extend onto corresponding portions of nested portion 92. After the individual substrates are fabricated and individualized (in one of the methods described above), the waveguide substrate 90 may be superimposed along the overlapping portion. As shown in FIG. 7B, the two portions of the flexible waveguide substrate 90 are shown to be positioned approximately perpendicular to each other, with the two portions of the overlapping portion extending outwardly. This alignment allows the light source and / or imaging device (both not shown) to be easily located adjacent or close to the individual waveguides 34 of the highways 36a and 36b on both sides of the overlapping portion 92.

Although the invention has been described in some detail for clarity of understanding, it is clear that certain modifications and changes can be realized within the scope of the appended claims. Accordingly, the disclosed embodiments are to be understood as illustrative and not restrictive, and the invention is not to be limited to the details given herein, but should be defined by the scope of the following claims and equivalents.

Claims (23)

Flexible substrate, A transparent first optical layer formed on the flexible substrate and having a first refractive index, A second optical layer formed on the first optical layer and patterned to form each of a plurality of optical elements and waveguides, the second optical layer having a second refractive index greater than the first refractive index, and A third optical layer formed on the second optical layer, the third optical layer having a third refractive index less than the second refractive index, And the substrate and the first, second and third optical layers form a flexible waveguide substrate. The method of claim 1, Wherein the first and third indices are substantially the same. The method of claim 1, And the flexible substrate comprises a material of either plastic or polycarbonate. The method of claim 1, And the second optical layer is further patterned to form a plurality of internal reflective surfaces, respectively, between the plurality of optical elements and the waveguides. The method of claim 4, wherein The plurality of optical elements are formed on a first surface of the waveguide substrate and the plurality of waveguides are formed on a second surface of the waveguide substrate, the first surface and the second surface being substantially perpendicular to each other Phosphorus device. The method of claim 1, Wherein the optical elements comprise one of lenses, diffraction gratings, filters, Bragg gratings, or coupling horns. The method of claim 1, And the plurality of optical elements patterned in the second optical layer are aligned in multiple layers. The method of claim 7, wherein And interleaved the plurality of optical elements of the multilayer. The method of claim 1, A light based touch screen substantially formed with a flexible waveguide substrate around a touch screen periphery, a first subset of the plurality of optical elements of the flexible waveguide substrate configured to provide light adjacent the light based touch screen, and the light based And a second subset of optical elements of said flexible waveguide substrate configured to detect data inputs made to a touch screen. The method of claim 9, And a light source optically coupled to the waveguides respectively coupled with the first subset of optical elements. The method of claim 10, And an imaging device optically coupled to the waveguides respectively coupled with the second subset of optical elements. A plurality of flexible waveguide substrates comprising a flexible substrate formed thereon, Each of the flexible waveguides, A transparent first optical layer formed on the flexible substrate and having a first refractive index, A second optical layer formed on said first optical layer and patterned to form each of a plurality of optical elements and waveguides, said second optical layer having a second refractive index greater than said first refractive index, and And a third optical layer formed on said second optical layer, said third optical layer having a third refractive index smaller than said second refractive index. The method of claim 12, And the plurality of flexible waveguide substrates are arranged in parallel strips on the flexible substrate. The method of claim 12, The flexible substrate is a continuous strip and the flexible waveguide substrates are formed in series on the flexible substrate. The method of claim 12, And the waveguide substrate comprises a plurality of optical elements and waveguides. The method of claim 15, And the optical elements are arranged and interposed in a multilayer. The method of claim 15, Wherein the optical elements comprise one of lenses, diffraction gratings, filters, Bragg gratings, or optical elements of connecting horns. The method of claim 12, And the flexible waveguide substrates are further patterned to form a plurality of internal reflective surfaces, respectively, between the plurality of optical elements and the waveguides. The method of claim 18, The plurality of optical elements are formed on a first surface of the flexible waveguide substrate and the plurality of waveguides are formed on a second surface of the flexible waveguide substrate, the first surface and the second surface being substantially relative to each other. Right angle device. Providing a first optical layer having a first refractive index on the flexible substrate, Providing a second optical layer on the first optical layer, the second optical layer having a second refractive index greater than the first refractive index, Patterning the second optical layer to respectively form a plurality of optical elements and waveguides, and Providing a third optical layer on the second optical layer, the third optical layer having a third refractive index lower than the second refractive index, And the flexible substrate and the first, second and third optical layers form a flexible waveguide substrate. The method of claim 20, And forming a plurality of flexible waveguide substrates on the substrate. The method of claim 21, Forming the plurality of flexible waveguide substrates, Providing the first, second and third optical layers in parallel strips on the substrate, and Cutting the substrate to individualize the individual flexible waveguide substrates. The method of claim 22, Forming the plurality of flexible waveguide substrates, Providing the first, second and third optical layers in series on a continuous strip of the flexible substrate at spatial intervals, and Cutting the continuous flexible substrate at the spatial intervals to individualize the individual waveguide substrates.

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