RU2548923C2 - Coordinate measuring device - Google Patents

Abstract

FIELD: physics.

SUBSTANCE: coordinate measurement device contains the first and the second radiators, the photodetector optically interfaced to them and covering a part of perimeter of sensing surface and the specialized calculator the outputs of which are connected to the first and second radiators, and the input is connected to the photodetector output. And the coordinate measurement device in addition contains the third radiator, optically interfaced to a photodetector, meanwhile the photodetector is designed in the form of two linear sets of pixels - upper and lower. The first and second radiators are in the plane of the upper set, and the third - in the plane of the lower set of pixels. The specialized calculator that is a part of the device performs alternate actuation of each radiator, input of values of illumination of pixels and measurement of a period between a shading of the upper and lower sets of pixels. Using these data the specialized calculator determines the coordinates and speed of a finger or a stylus which has toughed the sensing panel.

EFFECT: expansion of functionality, namely in addition to coordinates of a finger-tip or a sticker, determination and its speeds.

2 cl, 8 dwg

Description

The invention relates to techniques for optoelectronic systems and, in particular, to optical touch panels. The proposed device differs from devices of a similar purpose by its expanded functional capabilities, namely, by measuring the speed at which a finger or stylus touches the touch panel. The speed of contact with the touch panel actually displays the force of impact on graphic images, for example, on a monitor screen, which in turn expands the possibilities of interactive interaction. A mechanical analogue of this interaction can be a piano keyboard, the impact force in which determines the sound volume of the corresponding keys.

In general, measuring the speed of touch requires a high speed of updating information about the position of the fingertip or stylus at least at two points adjacent to the surface of the touch panel.

A number of touch panels are known based on optical methods for determining coordinates.

So, for example, a large group of such devices is formed by those that use the triangulation method. 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 located on three sides of the quadrangular screen is used. Further, using 2 scanning optical transceiver 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, a specialized computer, which is part of these devices, registers the angular coordinates of the shaded area. The presence of mechanical optoelectronic scanners in these devices does not allow us to obtain the speed required to determine the speed of touch.

A number of devices have also been proposed in which the triangulation method is implemented on 2 convergent television cameras located at the corners of the touch screen. So, in US patent No. 8164581 dated 04/24/2012 [5], in addition, 2 sources of infrared (IR) radiation are used, which in turn illuminate the reflectors located along the sides of the screen and reflecting the light flux incident on them towards the television cameras . Further, using a specialized computing device associated with television cameras, the coordinates of the object (finger, stylus) crossing the propagation path of the 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 quotation elements. The use of television cameras in all of these devices limits the speed of updating information to at least the frequency of their frame scan, which is insufficient to measure the dynamic characteristics of finger movement.

A large group of optical touch panels is formed by devices that use optical fibers in their composition. These are devices described, for example, in US Pat. No. 7,477,816 dated January 13, 2009 [10], No. 7627209 dated December 1, 2009 [11], No. 7496265 dated February 24, 2009 [12], No. 7805036 dated September 28, 2009 .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 proposed in US patent No. 7809221 from 10.10.2010, [17] - photodiode array. However, all these solutions do not allow, in principle, to solve the problem of measuring the speed of touch with the finger of the operator or the stylus of the touch surface.

Also known is the device proposed in the patent of the Russian Federation No. 2278423 dated 10/15/2004 [18] and which is the prototype of the present invention, containing two IR emitters connected to the outputs of a specialized 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. Moreover, as a result of the functioning of this device, a so-called sensor field is formed, formed by the intersection of the flows of the first and second emitters on the photosensitive surface of the photodetectors. By alternately turning on the IR emitters, a specialized calculator enters the coordinates of the shaded photodetectors and determines the coordinates of the finger (stylus) that crossed the path of radiation propagation, i.e. entered the sensory field.

The aim of the invention is to expand the functionality, namely, in addition to the coordinates of the fingertip or sticker, the definition and its speed.

To do this, in the known device containing the first and second emitters, a photodetector optically coupled to them and covering part of the perimeter of the sensor surface and a specialized computer, the outputs of which are connected to the first and second emitters, and the input of which is connected to the output of the photodetector, a third emitter is introduced, optically paired with a photodetector, the optical photodetector containing two rows of pixels - the upper and lower, while the upper row is in the plane of the first emitter, and the bottom d - in a third emitter to the plane, in addition, the pixels of the upper and lower rows may be shifted relative to each other and formed by a result of operation of the sensor unit is enclosed between these two planes. A specialized calculator, which is part of the device, turns on one of the emitters in turn, enters the values of the light signals of the photodetector pixels for each of them, and calculates the coordinates and speed of the touch point with a finger or a sticker on the bottom surface of the sensor field.

Figure 1 shows the functional diagram of the proposed device,

Where:

1,2,3 - IR sources, with solid angles

radiation propagation, Ψ ₁ , Ψ ₂ , Ψ _3, respectively;

4 - photodetector;

5 - specialized computer.

Figure 2 shows an example implementation of the photodetector 4, where:

6 - printed circuit board;

7 - phototransistors or photodiodes forming sensitive elements - pixels, photodetector 4.

Figure 3 shows the geometric arrangement of the pixels of the photodetector, 2 emitters and the spatial fragment of the finger, where:

P _n , P _{n + 2} , P _{n + 4} , P _{n + 6} ... - pixels of the upper row, odd;

P _{n + 1} , P _{n + 3} , P _{n + 5} , P _{n + 7} ... - pixels of the lower row, even;

P - spatial fragment of the finger of the operator;

V is the velocity vector of the point a;

- тень фрагмента П, формируемая действием 1-го излучателя; $$T_P^{\mathrm{one}}$$

- shadow of fragment P formed by the action of the 1st emitter;

- тень фрагмента П, формируемая действием 3-го излучателя; $$T_P^3$$

- shadow of fragment P formed by the action of the 3rd emitter;

l is the distance between the upper and lower rows of pixels and between the optical centers of the 1st and 3rd emitters.

Figure 4 shows a geometric diagram of the formation of planes, limiting above and below the sensor field, where:

S is the upper plane;

T is the lower plane.

Figure 5 shows the General case of the relative positions of the 1st, 2nd and 3rd emitters, where:

m is the distance between the optical centers 1 and 3 of the emitters;

c, d, e - optical axis 1, 2 and 3 of the emitters;

a is the line along which the optical centers of the upper row of pixels are aligned;

b is the line along which the optical centers of the lower row of pixels are aligned;

R is a straight line perpendicular to lines a, b and c.

Figure 6 shows the geometric diagram of the calculation of coordinates relative to the OXY system.

Figure 7 shows the second embodiment of the photodetector 4, with offset half the inter-pixel distance relative to the upper, lower row of pixels, where:

d is the inter-pixel distance.

The proposed device (figure 1) operates as follows.

Specialized computer 5 sequentially, with a time interval Δt, includes one of the emitters 1, 2 or 3. These emitters are infrared diodes, the radiation flux of which propagate in solid angles Ψ ₁ , Ψ ₂ and Ψ _3, respectively, and propagate towards the photosensitive surface photodetector 4 (optically coupled to it). The photodetector 4 is a two-row set of photodiodes or phototransistors (pixels) located, for example, on a ribbon circuit board with a certain step, as it is shown in figure 2. The signal from the output of the photodetector 4, for each switched-on emitter 1, 2, 3, is entered into the memory of a specialized computer that determines the coordinates and speed of the finger that passed through the working area of the device.

и $$T_{П}^3$$

от действия излучателей 1 и 3, расстояние между оптическими центрами которых l равно расстоянию между верхним и нижним рядами пикселей фотоприемника 6. На фиг.4 изображено образование плоскостей S T, прохождение через которые пальца оператора вызывает затенение соответствующих пикселей фотоприемника 4.Figure 3 shows an example of the formation of shadows $$T_P^{\mathrm{one}}$$

and $${\mathrm{<figure-callout\; id="3"\; label="T\; P"\; filenames="00000012.png,00000013.png"\; state="\{\{state\}\}">T\; </figure-callout>}}_P^{}$$

from the action of emitters 1 and 3, the distance between the optical centers of which l is equal to the distance between the upper and lower rows of pixels of the photodetector 6. Figure 4 shows the formation of planes ST, passing through which the operator’s fingers obscure the corresponding pixels of the photodetector 4.

We assume that the signal values (after threshold processing) from the illuminated pixels are 1, from the shaded ones - 0, and the pixel states P _N ... P _{N + 15} shown in Fig. 3 are in the form of a set - {u _n , u _{n + 1} , ... u _{n + l4} , u _{n + l5} }. When a finger fragment P moves at a certain speed V, in the direction of the plane S, and after it intersects in the direction of the plane T (Fig. 4), the values of the signals from these pixels at times t ₀ - t ₁₀ can have, for example, the following values -

t0 → {1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1},

t1 → {1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1},

t2 → {1,1,1,1,1,1,1,1,1,0,1,1,1,1,1,1,1,1},

t3 → {1,1,1,1,1,1,1,1,1,0,1,1,1,1,1,1,1,1},

t4 → {1,1,1,1,1,1,0,0,0,0,0,0,0,1,1,1,1,1},

t5 → {1,1,1,1,1,1,0,0,0,0,0,0,0,1,1,1,1,1},

t6 → {1,1,1,1,1,1,0,0,0,0,0,0,0,1,1,1,1,1},

t7 → {1,1,1,1,1,1,0,0,0,0,0,0,1,1,1,1,1,1},

t8 → {1,1,1,1,1,1,0,0,0,0,0,0,1,1,1,1,1}}

t9 → {1,1,1,1,1,1,0,0,0,0,0,0,0,1,1,1,1},

t10 → {1,1,1,1,1,1,0,0,0,0,0,0,0,1,1,1,1,1}.

Those. in this example, the shadow reached the top line of pixels at time t ₂ and moved from the top line of pixels to the bottom at time t ₇ . Due to the fact that the shadow size overlaps several pixels, it is clear that first the shadow (lower fingertip) overlapped one pixel of the upper row at time t ₂ , t ₃ , and then, as fragment P moves to the lower plane T, neighboring pixels were obscured top row at time t ₄ , t ₅ , t ₆ . After the shading of one pixel of the lower row at time t ₇ , with further movement of the finger (if there is no obstacle to this), the neighboring pixels of the lower row will be shaded at times t ₈ , t ₉ , t ₁₀ .

Thus, the movement of the fragment П by the distance I, between the upper and lower lines of the pixels on the photodetector 4, occurred during a time equal to t ₇ - t ₂ - Given that the emitters 1,2,3 are turned on at time intervals Δt, the time interval between inclusions of the 1st and 3rd emitters is equal to 2Δt, the speed of the fragment F is equal to:

$$V_P=\frac{\mathrm{<figure-callout\; id="5"\; label="l"\; filenames="00000015.png"\; state="\{\{state\}\}">l</figure-callout>}}{5\cdot 2\cdot \Delta t}$$

In general, the speed of contact is:

one)

; $$V_P=\frac{l}{\pi }$$

;

where l is the distance between the upper and lower rows of pixels of the photodetector 4;

τ is the time interval between the first appearance of a shadow on the upper row of pixels and the first appearance of a shadow on the lower row of pixels.

In the General case, the location of the photodetector and emitters, shown in figure 5, the emitter 3 can be located so that the projection of the line m on a straight line R, perpendicular to lines a , b and c, is equal to the value l. The optical axes c and d fall on line a , while the optical axis e falls on line b.

The calculation of the coordinates (X, Y) of the fragment P is performed according to the geometric diagram shown in Fig.6. The formulas for their calculation [18] have the form:

2)

$$\{\begin{array}{l}\frac{Y-Y_{\mathrm{one}}}{Y_{\mathrm{one}}^{em}-Y_{\mathrm{one}}}=\frac{X-X_{\mathrm{one}}}{X_{\mathrm{one}}^{em}-X_{\mathrm{one}}};\\ \frac{Y-Y_2}{Y_2^{em}-\mathrm{<figure-callout\; id="2"\; label="Y"\; filenames="00000012.png,00000013.png"\; state="\{\{state\}\}">Y</figure-callout>}{}_2}=\frac{X-X_2}{X_2^{em}-{\mathrm{<figure-callout\; id="2"\; label="X"\; filenames="00000012.png,00000013.png"\; state="\{\{state\}\}">X</figure-callout>}}_2}.\end{array}$$

where: (X ₁ , Y ₁ ) - the coordinates of the centers of the shadows formed from the action of the first emitter;

(X ₂ , Y ₂ ) - the coordinates of the centers of the shadows formed from the action of the second emitter;

) - координаты первого излучателя;( $$X_{\mathrm{one}}^{em},Y_{\mathrm{one}}^{em}$$

) are the coordinates of the first emitter;

) - координаты второго излучателя.( $$X_2^{em},Y_2^{em}$$

) are the coordinates of the second emitter.

Specialized calculator 5 performs:

- input signal values corresponding to the illumination values of the pixels of the first and second rows of the photodetector 4;

- threshold processing of these signals, i.e. decision making - “pixel shaded” / “pixel lit” (0/1);

- time measurement τ;

- determination of the values (X ₁ , Y ₁ ) and (X ₂ , Y ₂ );

- calculations of coordinates and speed, according to formulas 1 and 2;

- the issuance of results.

To improve the accuracy of determining the coordinates, the bottom row of pixels of the photodetector should be offset relative to the pixels of the top row by half a sample of d, as shown in Fig.7. The accuracy of measuring the coordinates of the shadow on the surface of the photodetector increases by a factor of 2, with an increase in the error in measuring speed.

On Fig shows a photograph of the photodetector 4, made for use in an experimental sample of this device. To expand the working area, the photodetector contains four rows of phototransistors (type КР3216Р3С from Kingbright). As a specialized calculator, this device uses a system on a chip (SoC), made on a FPGA type XC6SLX150-CSG484 from Xilinx.

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

Claims (2)

1. The coordinate measurement device containing the first and second emitters, a photodetector optically coupled to them and covering part of the perimeter of the sensor surface and a specialized computer, the outputs of which are connected to the first and second emitters, and the input is connected to the output of the photodetector, characterized in that it further comprises the third emitter connected to the output of a specialized computer and optically coupled to a photodetector, in addition, the optical photodetector contains two rows of pixels - the top the lower one, while the upper row is in the plane of the first and second emitters, and the lower one is in the plane of the third emitter, and the sensor field generated as a result of the operation of this device is enclosed between these planes, and a specialized calculator turns on one of the emitters in turn and enters light signals of the pixels of the photodetector for each of them and the calculation of the coordinates and speed of the point of contact with the finger of the bottom surface of the sensor field. 2. The device according to claim 1, characterized in that the lower row of pixels is offset relative to the upper row by half the inter-pixel distance.

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