RU2541849C2 - Light waveguide-based touch panel - Google Patents

Abstract

FIELD: measurement equipment.

SUBSTANCE: invention relates to optical-electronic instruments for information input into computer systems. The offered touch panel contains a set of light waveguides, designed as channels in a polymeric base and laying parallel to the touch surface. The touch panel also contains a photodiode array optically connected to output ends of light waveguides, connected to the valuator output. Besides the touch panel contains two point radiators optically connected to input ends of light waveguides and connected to the valuator outputs. The valuator performs sequential actuation of all radiators, input of the signals, corresponding to each radiator from the photodiode array, and also performs calculation of the position of a pin or stylus using the values of these signals.

EFFECT: simplification of the touch panel design due to exception of the second set of light waveguides.

3 cl, 6 dwg

Description

The present invention relates to techniques for optoelectronic measuring systems, TouchScreen panels and devices for inputting information into computer systems and control systems. The proposed touch panel differs from devices of a similar purpose in the simplicity of design and low cost of manufacture. With its help, you can implement new options for their design.

A number of devices of a similar application are known using optical methods for determining the coordinates of a touch point with a finger or a stylus on the surface of a screen (monitor).

A large group of such devices is formed by those that use the triangulation method for determining the coordinates of the touch point. So, in the devices proposed in US patent No. 6480187 dated 12/12/2002 [1], No. 6492633 dated 12/10/2002 [2], No. 6844539 dated January 18, 2005 [3], No. 7522156 dated April 21. 2009 [4], a regular reflective structure is used located on three sides of the quadrangular screen. Further, using 2 scanning transmit-receive optical modules located on the edges of the fourth side, the level of radiation reflected from this structure is analyzed. When a finger (stylus) appears on their way, the calculator, which is part of these devices, registers the angular coordinates of the shaded area. The disadvantage of this class of devices is that the receiving modules are mechanical optoelectronic scanners.

There is also a group of devices in which the triangulation method for determining the coordinates of the touch point is based on 2 convergent and television cameras located in the corners of the touch screen. So, in US Pat. . Further, using a computing device associated with television cameras, the coordinates of the object (finger, stylus) crossing the propagation path of reflected radiation are calculated. In US patents No. 7333094 dated February 19, 2008 [6], No. 7333095 dated February 19, 2008 [7], No. 7477241 dated January 13, 2009 [8], No. 7573465 dated August 11, 2011 [9] An infrared emitter is used, made in the form of an optical element with a special spatial geometry, which allows directing the radiation supplied to its end from the light source towards television cameras. The disadvantage of this type of device is the need for preliminary geometric alignment of the television cameras included in their composition, the use in the manufacture of such devices a large number of mounting and alignment elements.

A significant simplification of such devices can be obtained using optical fibers in their composition. These include devices described in US patent No. 7477816 dated January 13, 2009 [10], No. 7627209 dated December 1, 2009 [11], No. 7496265 dated February 24, 2009 [12], No. 7805036 dated September 28. 2010 [13], No. 7817886 dated 10/19/2010 [14], No. 7957615 dated June 7, 2011 [15], No. 8111958 dated February 7, 2012 [16]. All of them contain one set of receiving and transmitting optical fibers, and the output ends of the transmitting optical fibers are optically coupled to the input ends of the receiving optical fibers, and IR radiation from a laser or LED is supplied to their input ends. The output ends of the receiving optical fibers are optically coupled to photodetectors, or, as suggested in US Pat. No. 7809221 of October 5, 2010 [17], a photodiode array.

A device of a similar purpose is also known, proposed in RF patent No. 2278423 dated October 15, 2004 [18], containing two infrared emitters connected to the outputs of the computer and optically coupled to photodetectors connected to the same computer, the location of the photosensitive surface of which covers part of the perimeter of the controlled surface. By alternately turning on the IR emitters, the calculator enters the coordinates of the shaded photodetectors and determines the coordinates of the finger (stylus) that crossed the path of radiation propagation.

The closest technical solution to the proposed invention is US patent No. 8184108 from 05.22.2012, [19], which uses optical fibers formed on a polymer substrate. This device includes two sets of optical fibers - receiving and transmitting, the input ends of the first of which are optically coupled to the output ends of the second set, and the output ends are connected to the photodiode array, while the input ends of the second set of optical fibers are optically coupled to the IR emitter. At the same time, its radiation passing along each of the optical fibers forms streams at their output ends that propagate along the sensor surface and reach the input ends of the receiving optical fibers. Further propagating along them, the radiation reaches the photodiode array and is recorded by the processor included in the device. By analyzing the brightness of the individual elements of this array, the processor determines the zone in which the optical flows intersected with a finger or stylus. The disadvantages of this device include the presence of a second set of optical fibers, complicating the design of the device.

The aim of the invention is to simplify and reduce the cost of optical, in particular infrared, touch panels.

To do this, in a known device containing a set of optical fibers, made in the form of cavities in a polymer material, the input ends of which are located on the border of the touch panel and are optically coupled to the infrared light source included in the device, and the output ends of this set of optical fibers are optically connected to the photodiode array , the output of which is in turn connected to the input of the calculator, a second source of IR illumination is introduced, optically coupled to the input ends of the optical fibers, the first and second emitters being made in the form of The values associated with the output of the calculator, while their fluxes fall on the input ends of all the receiving fibers, and the intersection of both fluxes on the input ends forms the working area of the touch panel, in addition, the calculator turns on one of the emitters and, by entering the signal values from the photodiode array for each of the emitters, calculates the coordinates of the finger or stylus that crossed the work area.

In FIG. 1 shows a functional diagram of the proposed device, where:

1, 2 - sources of infrared illumination, with a solid angle of radiation propagation ψ ₁ and ψ _2, respectively,

3 - photodiode array

4 - calculator,

5 - polymer base,

6 - optical fibers.

In FIG. 2 shows a geometric diagram of the optical fibers formed in the polymer base, where:

Ω is the input end

7 - output end reflector,

φ is the radiation flux emanating from the reflector 7.

In FIG. 3 shows a geometric diagram of a touch panel made with two layers of polymer bases, where:

8 - showdown in the upper layer,

9 - the bottom layer,

ω - radiation flux passing through the opening 8.

In FIG. 4 shows the optical-geometric diagram of the formation of the image of the shadows from the finger of the operator, where:

10 - finger overlapping optical streams,

11 - shadows formed by illuminating a finger with emitters 1 and 2.

In FIG. 5 shows an optical model of the formation of partial shading of the input end of the fiber, where:

- площадь освещенного торца i-го световода,

- the area of the illuminated end of the i-th fiber,

- площадь затененного торца i-го световода,

- the area of the shaded end of the i-th fiber,

- площадь освещенного торца i+1-го световода,

- the area of the illuminated end of i + 1-st optical fiber,

a is the width of the end

X _i - the linear coordinate of the edge of the end.

In FIG. 6 is a geometric diagram of a separate fiber.

The operation of the device is as follows.

IR emitters 1 and 2 (Fig. 1) create IR radiation streams whose solid propagation angles ψ ₁ and ψ ₂ respectively cover the input ends of the optical fibers 6, made in the form of a base board 5, and are placed so that the spatial pointer 10 placed between and in front of them cast a shadow 11 at the inputs of the optical fibers 6, which is illustrated in FIG. four.

The polymer base is a polymer plate, for example polymethylmethacrylate [20], which for greater strength can be applied to a glass surface.

The optical fibers (Fig. 6) are formed using a special stamp as follows: a stamp is pressed under high pressure and at high temperature into a layer of polymethyl methacrylate, which is currently in a liquid state. During cooling, the polymer fixes the required shape, after which the stamp is removed [21].

As shown in FIG. 2, the input apertures of the optical fibers are on the side facing the infrared emitters, and the reflectors 7 formed at the ends of the optical fibers direct their reaching radiation φ towards the photodiode array. To reduce optical loss, the lateral surfaces of the optical fibers 6 may have a mirror coating, for example, of deposited aluminum [22].

Polymer bases with the optical fibers formed in them can be stacked on top of each other so that the input ends of the optical fibers are staggered, which will increase the resolution of the device. This embodiment is shown in FIG. 3. In this case, the upper base should have openings 8, which allow optical fluxes ω directed upward by the reflectors 7 to obtain optical coupling with the photodiode array.

, то можно записать:The resolution can also be increased by expanding the horizontal extent of the input apertures, as illustrated in FIG. 5. If we assume that the shadow boundary extends at a distance ΔΧ _i from the left edge of the end face, and its width is equal to a, and that the signal taken from the photodiode array and corresponding to the partially illuminated i-th end of the fiber is equal to U ⁱ and is proportional to the illuminated area

, then you can write:

Similarly, for a fully illuminated end close to the i-th, we can write:

From 1 and 2 you can get:

Thus, the refined X - coordinate of the right border of the shadow is X _i + ΔX _i .

,

) и (

,

), определяет координаты пальца (стилуса), аналогично тому, как описано в [18].Calculator 4 according to the coordinates of the centers of shadows formed from the action of the first and second emitters - (X ₁ , Υ ₁ ) and (X ₂ , Υ ₂ ), and the coordinates of these emitters in the coordinate system OΧΥ - (

,

) and (

,

), determines the coordinates of the finger (stylus), similar to that described in [18].

Information sources

1. US patent No. 6480187 from 12/12/2002

2. US patent No. 6492633 from 12/10/2002

3. US patent No. 6844539 from 01/18/2005

4. US Patent No. 7522156 of 04/21/2009

5. US patent No. 8164581 from 04.24.2012

6. US patent No. 7333094 of 02.19.2008.

7. US patent No. 7333095 of 02/19/2008.

8. US patent No. 7477241 from 01/13/2009

9. US patent No. 7573465 from 08/11/2011

10. US patent No. 7477816 from 01/13/2009

11. US Patent No. 7627209 of December 1, 2009.

12. US Patent No. 7496265 of 02.24.2009

13. US patent No. 7805036 from 09/28/2010.

14. US patent No. 7817886 from 10.19.2010.

15. US patent No. 7957615 from 06/07/2011

16. US Patent No. 8111958 of February 7, 2012.

17. US patent No. 7809221 from 10.10.2010

18. RF patent No. 2278423 of 10/15/2004

19. US patent No. 8184108 of 05.22.2012.

20. Arakcheeva E.M., Tanklevskaya E.M., Nesterov S.I. Obtaining photonic crystals in structures based on semiconductors and polymers using the nanoimprint method. Journal of Technical Physics, 2005.

21. Lapshinov B.A. Technology of lithographic processes. Textbook - Moscow State Institute of Electronics and Mathematics. M., 2011.

22. Dorofeev S.G., Vasiliev R.B. Vacuum spraying of thin-film structures. Moscow State University Lomonosov. M., 2011.

Claims (3)

1. A touch panel containing a set of optical fibers made in the form of channels in a polymer base and lying parallel to the sensor surface, a photodiode array optically coupled to the output ends of the optical fibers connected to the input of the computer, and an emitter optically coupled to the receiving ends of the optical fibers, characterized in which contains a second emitter, optically coupled to the receiving ends of the optical fibers, both emitters connected to the outputs of the computer and made in the form of point, and their optical flows are blocked in odnye ends of optical fibers, wherein the calculator performs alternately switch each of the emitters, each emitter respective input signals from the photodiode array and the subsequent calculation of the position of the finger or stylus on the values of these signals. 2. The touch panel according to claim 1, characterized in that it has at least two sets of receiving optical fibers made in polymer bases, stacked on top of each other, with the upper closest to the photodiode array having openings for optical communication of the lower base with the photodiode array and the input ends of the optical fibers of the upper and lower sets are offset relative to each other. 3. The touch panel according to claim 1 or 2, characterized in that the optical fibers have extended input apertures facing the first and second emitters.

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