CN202404555U - Optical device for optical touch positioning - Google Patents

Abstract

The utility model provides an optical device for optical touch positioning. The optical device comprises an infrared linear light source assembly which is arranged at the bottom and two sides of a touch area and actively emits light; the infrared linear light source assembly comprises a luminous source and an optical oscillating cavity which is provided with only one light emergent port; the luminous source is arranged in the optical oscillating cavity; and the infrared linear light source assembly also comprises a light diffusion plate and a secondary light distribution lens, wherein the light diffusion plate is arranged at the light emergent port of the optical oscillating cavity, and the secondary light distribution lens is arranged between the luminous source and the light diffusion plate. According to the optical device, infrared light emitted by the luminous source is secondarily distributed through the secondary light distribution lens, so that the optical device emits light uniformly; and the light diffusion plate is added at a position where the light emergent port is located, so that the light field is further homogenized, a really uniformly luminous infrared linear light source is provided for touch equipment, the stability and the accuracy of touch positioning are improved, and error triggering is reduced.

Description

The optical devices that are used for the optical touch location

Technical field

The utility model relates to the optical touch field, relates in particular to a kind of optical devices that are used for the optical touch location.

Background technology

Traditional optical touch-control locator meams, as shown in Figure 1, the mode that adopts two angles of screen end to place LED and camera, and the dispersion angle of LED be 90 ° or more than, the shooting angle of camera be 90 ° or more than; The retroreflecting bar is all placed on screen three limits, and its effect is to reflect back light towards original direction; When touch point (shading object arbitrarily) was arranged in the screen, camera can photograph light field and change, and can calculate the angle at touch-control place according to the variation of this light field; Then can confirm the position of touch point through two cameras then at screen.

But above-mentioned touch technology can only carry out single-point touch, and is difficult to be used in the giant-screen.When screen size become big after, for example 80 cun, so since the light intensity of reflection bar reflection excessively a little less than, will be difficult to recognize that the caused light field of touch point changes.Simultaneously, when using reflection bar, in order to obtain the higher light field of brightness ratio; Need to improve the width of reflection bar; Can cause whole optical alignment frame excessive height like this, influence the effect that pen attractive in appearance and disconnected connects pen, that is to say that touch control object does not touch the variation that screen promptly causes the touch screen light field as yet; Be very easy to cause erroneous judgement in this case, the effect of influenced touch-control, writing.

For addressing the above problem, existing at present people proposes to adopt the mode of active illuminating light source.With reference to figure 2, the infrared linear light source of active illuminating on the cloth in the base of touch area and dual-side, this light source infrared light that sheds uniformly.Two angle ends at screen are placed camera, and the shooting angle of these two cameras is all greater than 90 °.At this moment, in infrared wire source imaging and the camera, when having touch control object in the screen, the light of infrared linear light source is blocked, and has caused that the light field that camera photographs changes, and therefore the variation according to this light field then can position.Because this technology adopts the light source of active illuminating, so can not receive the constraint of distance, therefore can be applied on large-sized display screen, the situation that screen promptly causes touch-control can not take place not touch in the situation of the disconnected pen of its company's of efficiently solving pen.

Yet; The technology of above-mentioned employing active illuminating light source; When carrying out the touch-control location, still have a problem, promptly the infrared linear light source of active illuminating can't provide a uniform light face truly, and then causes the lower problem of accuracy of touch-control location.As everyone knows; When carrying out the touch-control location; Camera need be taken a luminous light face and carry out the judgement of touch-control as benchmark; So need the formed light field of overall optical face can reach certain homogeneity, can't accurately judge facula position otherwise cross zone strong or that light field is weak excessively in light field, this be because:

One, can make camera saturated in the strong excessively zone of light field,, can't cause that this light field changes, thereby also just can't accurately judge facula position if when in this zone touch control object being arranged like this;

The image that two, can make camera collect in the weak excessively zone of light field is low excessively, and caused light field changed not obviously when this will cause touch object, caused accurately judging facula position.While is in the also corresponding reduction of threshold value of the low excessively zone hot spot that extracts of light field; So just make the touch-control location technology receive interference of noise (this noise source might be that the electric current shakiness causes luminous light-intensity variation of LED or external ambient light interference etc.) easily; The light field that noise produced changes than is easier to above the hot spot threshold value, thereby causes false triggering.

Into two or more hot spots to a hot spot when simultaneously, the unevenness of light field also may cause hot spot to be judged.As shown in Figure 3; Fig. 3 (a) is the light field image of no touch, and Fig. 3 (b) is the light field image when having touch-control, and Fig. 3 (c) gets the image that difference draws for both; Dotted line among this figure is a threshold size; It is thus clear that if hot spot threshold value value is incorrect, will be judged as the image among Fig. 3 (c) two hot spots of existence, the situation that causes judging by accident occurs.

Through discovering, directly adopt infrared LED lamp bar, no matter be the passive luminous or form of active illuminating then, all be difficult to reach above-mentioned inhomogeneity requirement.This is because the luminous non-uniform phenomenon that just exists of common LED self, and is more intense in the light intensity of the less area L ED of the angle of divergence, the beam intensity ratio of the big area L ED of the angle of divergence a little less than, cause the formed light field undulate of overall optical face shape.With certain LED is example, and Fig. 4 is the distribution curve flux figure of this LED, can find out that from this figure its luminosity curve is very inhomogeneous, has so just caused its formed light field inhomogeneous.

Therefore, how for touch control device provides the accuracy of the infrared linear light source of a uniformly light-emitting with raising touch-control location, become problem demanding prompt solution.

The utility model content

For addressing the above problem, the utility model provides a kind of optical devices that are used for the optical touch location, and the infrared linear light source of a uniformly light-emitting can be provided for touch control device, and then improves the accuracy of touch-control location.

For realizing above-mentioned purpose, the utility model adopts following technical scheme:

A kind of optical devices that are used for the optical touch location; The infrared wire light source assembly that comprises the active illuminating of the base that is arranged on the touch area and dual-side; This infrared wire light source assembly comprises illuminating source, has only the optics vibration chamber of a light-emitting window; Said illuminating source is installed in the said optics vibration chamber; Said infrared wire light source assembly also comprises light diffusing sheet, secondary light-distribution lens, and said light diffusing sheet is arranged at the light-emitting window place in said optics vibration chamber, and said secondary light-distribution lens is arranged between said illuminating source and the light diffusing sheet.

Can find out that by above scheme the optical devices that are used for the optical touch location of the utility model carry out secondary light-distribution through secondary light-distribution lens to the infrared light that illuminating source sent, and make its more even light emission; Be positioned over illuminating source in the cavity that has only a light-emitting window simultaneously, can improve the utilization factor of light intensity like this; And add light diffusing sheet at the light-emitting window place, further the homogenize light field for touch control device provides the infrared linear light source of a uniformly light-emitting truly, thereby has improved the stability and the accuracy of touch-control location, has reduced false triggering.The optical devices that are used for optical touch location of the utility model implement simple and conveniently in addition, and cost is lower, compared with prior art, after introducing the secondary light-distribution technology, only need provide the LED lamp of smaller amounts promptly to can be the uniformity requirement that reaches equal.

Description of drawings

Fig. 1 is a traditional optical touch-control locator meams synoptic diagram;

Fig. 2 is the structural representation of the touch screen of employing active illuminating light source mode;

Fig. 3 carries out the effect synoptic diagram that hot spot into a hot spot when judging two hot spots;

Fig. 4 is the distribution curve flux figure of certain LED;

Fig. 5 is used for the structural representation of the optical devices of optical touch location for the utility model;

Fig. 6 is the taken touch screen synoptic diagram of left side camera;

Fig. 7 is not for to exist touch-control, to have the light intensity intensity contrast synoptic diagram that each pixel of camera is collected under the touch-control condition respectively;

Fig. 8 is the concrete implementation structure synoptic diagram of infrared backlight source;

Fig. 9 is the computation process synoptic diagram of the shape of secondary light-distribution lens;

Figure 10 is the shape synoptic diagram of the secondary light-distribution lens processed with PMMA;

Figure 11 is for to lack the light-field effects synoptic diagram that photographs under the light diffusing sheet situation.

Embodiment

The utility model provides a kind of optical devices that optical touch is located that are used for, to solve in the prior art no matter be that passive light source or active light source all can't be that touch control device provides the infrared linear light source of a uniformly light-emitting and then the problem of the accuracy that the reduction touch-control is located.

A kind of optical devices that are used for the optical touch location of the utility model; As shown in Figure 5; The infrared wire light source assembly that comprises the active illuminating of the base that is arranged on the touch area and dual-side; This infrared wire light source assembly comprises illuminating source, has only the optics vibration chamber of a light-emitting window, and said illuminating source is installed in the said optics vibration chamber, and said infrared wire light source assembly also comprises light diffusing sheet, secondary light-distribution lens; Said light diffusing sheet is arranged at the light-emitting window place in said optics vibration chamber, and said secondary light-distribution lens is arranged between said illuminating source and the light diffusing sheet.

Whole camera and arranging of infrared linear light source can be as shown in Figure 2, promptly place cameras at two angle ends of screen, the infrared linear light source of active illuminating on the base of touch area and dual-side cloth.The camera on the left side can photograph the linear light source of base and right edge so; With reference to figure 6; Under the situation that does not have touch-control, roughly as Fig. 7 (a) shown in, this meaning of scheming representative is the light intensity intensity that each pixel of camera is collected to the taken image of camera this moment.When having touch control object in the screen, the taken image of camera can change, shown in Fig. 7 (b).Then can calculate the position of hot spot according to the contrast of Fig. 7 (a) and Fig. 7 (b), promptly the location of pixels at hot spot place can be assumed to be A.Total number of pixels of supposing camera in addition is 1024, and the field angle of camera is 90 °, and 1024 pixels are divided into 1024 parts to 90 ° field angle, and the residing angle of this touch control object is θ=A * 90 °/1024 so.In like manner can calculate the residing angle of right camera touch control object, so according to these two angles, and the known coordinate figure that then can calculate touch point of screen size.

More than be the method for touch-control location, the utility model focus on adopting the infrared linear light source that uniformly light-emitting can be provided, below for specifically describing:

Be illustrated in figure 8 as the concrete way of realization of infrared backlight source, the light that infrared LED sends at first passes through secondary light-distribution lens, by these lens the light that infrared LED sent is carried out secondary light-distribution, makes its light field more even.Though the light field uniformity of luminance through behind the secondary light-distribution can reach good effect, can't use for this backlight.So another innovation part of the utility model is to have adopted light diffusing sheet, light field behind the secondary light-distribution is through accessing further homogenize behind the light diffusing sheet and the even light face that can take to camera being provided.

The described illuminating source of the utility model can be infrared LED (light emitting diode), infrared laser transmitter or other infrared light supply etc.Is that example describes with common infrared LED as illuminating source; The utility model needs at first the light that infrared LED sent to be carried out secondary light-distribution; This process realizes through before infrared LED, adding a secondary light-distribution lens; This secondary light-distribution lens carries out secondary light-distribution to the light that infrared LED sent, and makes its light field more even, and the light field uniformity of luminance behind secondary light-distribution can reach good effect.

In choosing the process of secondary light-distribution lens, its material, shape play determinative.As an embodiment preferably, said secondary light-distribution lens can be processed by the material that passes through infrared light.Concrete; The material of said infrared light can be below (including but are not limited to) one of several kinds: PMMA (polymethylmethacrylate), PC (Polycarbonate; Polycarbonate) or AB S (Acrylonitrile Butadiene Styrene, acrylonitrile-styrene-butadiene copolymer).

In addition, the shape of said secondary light-distribution lens can confirm that the lens of processing with PMMA are example according to refractive index, the energy conservation formula of the material of processing these lens, and then the computation process of the shape of this secondary light-distribution lens is specific as follows:

As shown in Figure 9, initial point O is a light source position among the figure, and the free form surface at A point place is the shape of secondary light-distribution lens, and the plane at B place is the objective plane of light source irradiation (being light diffusing sheet in the present embodiment).The light field that can make infrared LED send through secondary light-distribution lens is distributed on the light diffusing sheet uniformly.Distribution curve flux according to LED; Because LED is the characteristics of luminescence of similar lambert's type, certain variation can take place through the angle of divergence behind the lens to its light intensity in the light intensity as LED for

.According to the catadioptric law, can draw following formula:

${[1+n^2-2n(\stackrel{\→}{\mathrm{Out}}\·\stackrel{\→}{\mathrm{In}})]}^{1/2}\·\stackrel{\→}{N}=\stackrel{\→}{\mathrm{Out}}-n\·\stackrel{\→}{\mathrm{In}}$

Wherein, The vector representation form of radiation direction behind the light transmission secondary light-distribution lens that sends for LED,

Wherein x, z are the coordinate figure of secondary light-distribution lens, and H is the vertical range that target face leaves light source, x _dBe the coordinate figure on the x axle after the light arrival target face;

The vector representation form of radiation direction when getting into secondary light-distribution lens for LED,

Be the normal vector of secondary light-distribution lens curved surface, wherein (x z) is the curved surface of secondary light-distribution lens, then

So just can construct an One first-order ordinary differential equation, this differential equation is:

$\frac{\mathrm{dz}}{\mathrm{dx}}=(\mathrm{nD}-B)/(A-\mathrm{nC})$

Wherein, n is the refractive index of the material of secondary light-distribution lens, and the expression formula of A, B, C, D is following,

$\left\{\begin{array}{c}A=\frac{H-z}{\sqrt{{(x_d-x)}^2+{(H-z)}^2}}\\ B=\frac{x_d-z}{\sqrt{{(x_d-x)}^2+{(H-z)}^2}}\\ C=\frac{z}{\sqrt{x^2+z^2}}\\ D=\frac{x}{\sqrt{x^2+z^2}}\end{array}\right.---\left(1\right)$

But, also need another equation in order to untie this equation because there are two unknown numbers in above-mentioned formula.Because light follows law of conservation of energy in the air, promptly the luminous flux exported of light source equals to incide the resulting luminous flux of target face.The light intensity I that LED sent is a function relevant with the angle of divergence, therefore can get:

Wherein,

is the dispersion angle of LED; E is the illumination of target face, and A is the area size of LED when shining target face.Because LED is similar lambert's body;

can get in this integral formula more than formula substitution:

Be x at radius so _dThe zone in the luminous flux formula can be expressed as:

Contrast equation (2), (3) can draw:

Wherein,

Simultaneous formula (1), (4) promptly can construct one about x, the differential equation of z, and in order to solve this x, the value of z, available numerical solution is obtained x, the value of z and be x with the x axle, the y axle is that z retouches out curve, then this curve is the curve map of lens.This lens shape is similar to the heart-shaped first half, and is shown in figure 10.

As an embodiment preferably, said light diffusing sheet can be processed by plastic basis material or glass material.Further, said plastic basis material can be PMMA (polymethylmethacrylate), PC (Polycarbonate, polycarbonate) or PET (polyethylene terephthalate, polyethylene terephthalate).

The principle of work of light diffusing sheet is following: light is through the diffusion layer with plastic basis materials such as PMMA/PC/PET; When running into the medium different (diffusion particle) with its refractive index; The phenomenon of multi-angle, multidirectional refraction, reflection and scattering can take place, thereby reaches the light diffusion effect.If do not adopt light diffusing sheet, and only adopt general lens, the taken light field of camera will not be a uniform light face so, but photograph pointolite one by one, and will be shown in figure 11.

As an embodiment preferably, can post reflective membrane or be sprayed with reflecting material at the inwall in said optics vibration chamber, can in the utilization factor that improves light intensity, also play a effect like this to the light field homogenize.

Preferably, as shown in Figure 5, can optical devices the whole series of the utility model be enclosed in the middle of the aluminium frame.Because aluminium has 95% reflectivity to infrared light, this aluminium frame forms an optics vibration reflection chamber, can improve the utilization factor of light intensity, and can carry out homogenization to light field.This is because there is certain diffuse effect in light diffusing sheet itself; The part light intensity is reflected back toward in the cavity; Reflection chamber reflects this part light intensity again, sheds through seeing through diffuser plate after the reflection repeatedly like this, so just can reach and improve light intensity utilization factor and the inhomogeneity effect of light field.

Preferably, said infrared wire light source assembly can also comprise pedestal, and said pedestal is installed in the said optics vibration chamber, and said illuminating source, secondary light-distribution lens are installed on this pedestal.

The above is single led light field homogenize process, only needs above infrared LED and secondary light-distribution lens array are arranged, and can form backlight an of uniformly light-emitting.

Can find out that through above scheme the optical devices that are used for the optical touch location of the utility model carry out secondary light-distribution through secondary light-distribution lens to the infrared light that illuminating source sent, and make its more even light emission; Be positioned over illuminating source in the cavity that has only a light-emitting window simultaneously, can improve the utilization factor of light intensity like this; And add light diffusing sheet at the light-emitting window place, further the homogenize light field for touch control device provides the infrared linear light source of a uniformly light-emitting truly, thereby has improved the stability and the accuracy of touch-control location, has reduced false triggering.The optical devices that are used for optical touch location of the utility model implement simple and conveniently in addition, and cost is lower, compared with prior art, after introducing the secondary light-distribution technology, only need provide the LED lamp of smaller amounts promptly to can be the uniformity requirement that reaches equal.

Above-described the utility model embodiment does not constitute the qualification to the utility model protection domain.The modification of being done within any spirit and principle at the utility model, be equal to replacement and improvement etc., all should be included within the claim protection domain of the utility model.

Claims (10)

1. one kind is used for the optical devices that optical touch is located; The infrared wire light source assembly that comprises the active illuminating of the base that is arranged on the touch area and dual-side; This infrared wire light source assembly comprises illuminating source, has only the optics vibration chamber of a light-emitting window, and said illuminating source is installed in the said optics vibration chamber; It is characterized in that said infrared wire light source assembly also comprises light diffusing sheet, secondary light-distribution lens, said light diffusing sheet is arranged at the light-emitting window place in said optics vibration chamber, and said secondary light-distribution lens is arranged between said illuminating source and the light diffusing sheet.

2. the optical devices that are used for the optical touch location according to claim 1 is characterized in that said secondary light-distribution lens is processed by the material that passes through infrared light.

3. the optical devices that are used for the optical touch location according to claim 2 is characterized in that the material of said infrared light is polymetylmethacrylate, polycarbonate PC or acrylonitrile-styrene-butadiene copolymer ABS.

4. the optical devices that are used for the optical touch location according to claim 1 and 2 is characterized in that, the shape of said secondary light-distribution lens is confirmed according to the refractive index of processing the material of these lens, energy conservation formula.

5. the optical devices that are used for the optical touch location according to claim 1 is characterized in that said light diffusing sheet is processed by plastic basis material or glass material.

6. the optical devices that are used for the optical touch location according to claim 5 is characterized in that said plastic basis material is polymetylmethacrylate, polycarbonate PC or polyethylene terephtalate.

7. the optical devices that are used for the optical touch location according to claim 4 is characterized in that, the inwall in said optics vibration chamber posts reflective membrane or is sprayed with reflecting material.

8. the optical devices that are used for the optical touch location according to claim 4 is characterized in that said optical devices are enclosed in the middle of the aluminium frame.

9. the optical devices that are used for the optical touch location according to claim 8 is characterized in that said illuminating source is infrared LED or infrared laser transmitter.

10. the optical devices that are used for the optical touch location according to claim 1; It is characterized in that; Said infrared wire light source assembly also comprises pedestal, and said pedestal is installed in the said optics vibration chamber, and said illuminating source, secondary light-distribution lens are installed on this pedestal.

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