CN110515482B

CN110515482B - Infrared touch screen pressure sensing method based on surface deformation

Info

Publication number: CN110515482B
Application number: CN201910606235.8A
Authority: CN
Inventors: 王迪; 张忠伟; 李金鹏
Original assignee: ZAAG TECH Inc
Current assignee: ZAAG TECH Inc
Priority date: 2019-07-05
Filing date: 2019-07-05
Publication date: 2023-08-15
Anticipated expiration: 2039-07-05
Also published as: CN110515482A

Abstract

The utility model provides an infrared touch screen pressure sensing method based on surface deformation, which comprises the following steps: when the infrared touch screen applies pressure on the surface of the infrared touch screen, the pressure applied by the touch object on the touch surface is judged by utilizing the magnitude of a signal component formed by surface refraction in a surface light path of the infrared touch screen. The utility model has the advantages that: the utility model is sensitive when detecting relatively large pressure, when the pressure is large to a certain extent, the touch surface starts to deform, the larger the pressure is, the larger the deformation is, and compared with a normal state, the detected signal has larger difference.

Description

Infrared touch screen pressure sensing method based on surface deformation

Technical Field

The utility model relates to the technical field of photoelectric detection, in particular to an infrared touch screen pressure sensing method based on surface deformation.

Background

The pressure is generally simulated by the area of a detected object, and the larger the area is, the larger the pressure is, and the method has certain matching requirements on the size of the touch object and the set parameter value, such as setting the parameter corresponding to the size of the touch object, and when the touch object with the size of 10 mm is used, the simulation value of the pressure has great deviation, so that the pressure applied to the surface of the screen by the object cannot be truly reflected.

The utility model patent with publication number CN201600668U discloses a touch system, which detects deformation of a touch panel caused by touch by using a sensor, and then a wake-up circuit confirms whether the touch on the touch panel is an effective touch or a false touch according to the detected deformation of the touch panel, if the touch is a false touch, the touch system does not respond, if the touch is an effective touch, the touch system responds to the effective touch and generates a wake-up signal, and the main controller is woken up by the wake-up signal, so that the problem of false touch can be solved. However, this patent cannot detect the amount of pressure applied by a touch object on the touch surface, and cannot satisfy the touch application service requiring pressure data.

Disclosure of Invention

The utility model aims to provide an infrared touch screen pressure sensing method based on surface deformation, which can detect the pressure applied by a touch object on a touch surface.

In order to achieve the above purpose, the technical scheme adopted by the utility model is as follows: the pressure sensing method of the infrared touch screen based on the surface deformation comprises the following steps: when the infrared touch screen applies pressure on the surface of the infrared touch screen, the pressure applied by the touch object on the touch surface is judged by utilizing the magnitude of a signal component formed by surface refraction in a surface light path of the infrared touch screen.

In the infrared touch screen pressure sensing method based on surface deformation, the method further comprises the following step S before judging the pressure applied by a touch object on the touch surface: and recording the sampling intensity values of all the light paths of the touch screen in the non-touch state.

The pressure sensing method of the infrared touch screen based on the surface deformation further comprises the following step D after the step S: when the touch surface is touched, recording the intensity values of all light paths which do not pass through the touch point and are within a certain range from the touch point, calculating the difference value between the intensity values of the light rays and the intensity values of the light rays in a normal state, and then carrying out weighted average on the difference value of the light rays according to the distance from the touch point.

The pressure sensing method of the infrared touch screen based on the surface deformation further comprises the following step F after the step D: and carrying out table lookup through the coordinate positions of the touch points and the obtained weighted average value, and carrying out fuzzy matching to obtain the corresponding pressure.

Compared with the prior art, the utility model has the advantages that: the utility model is sensitive when detecting relatively large pressure, when the pressure is large to a certain extent, the touch surface starts to deform, the larger the pressure is, the larger the deformation is, and compared with a normal state, the detected signal has larger difference.

Drawings

FIG. 1 is a schematic diagram of a cross-sectional structure of an infrared touch screen according to the present utility model, wherein one end of the diagram is used as a transmitting end, and one end of the diagram is used as a receiving end, and a signal collected by the receiving end is composed of direct light and refracted light.

FIG. 2 is a schematic view of the touch surface in a pressureless state according to the present utility model.

FIG. 3 is a schematic view of the touch surface in a pressurized state according to the present utility model.

FIG. 4 is a schematic view of each optical path when the surface of the infrared touch screen is touched.

Detailed Description

The technical scheme adopted by the utility model is further described below with reference to the schematic diagram.

The utility model provides a pressure sensing method of an infrared touch screen based on surface deformation, which utilizes the magnitude of a signal component formed by surface refraction in a surface light path of the infrared touch screen to judge the magnitude of pressure applied by a touch object on a touch surface when the infrared touch screen applies pressure on the surface of the infrared touch screen.

As shown in fig. 1, the infrared touch screen includes an infrared touch screen surface 1, and the infrared touch screen has an emitting end 2 and a receiving end 3, where S1 is a correlation light, S2 is a refraction light, and T is a receiving virtual image.

When a certain amount of deformation occurs on the touch surface after the touch surface applies pressure (fig. 2 is a schematic diagram of a state that the touch surface is not under pressure, fig. 3 is a schematic diagram of a state that the touch surface is under pressure, a force applied F is given in fig. 3), the deformation affects the intensity of the refracted light (see fig. 4, which shows the position X of the touch object), so that the sum of the actual intensities collected by the receiving lamp is affected, and we perform a difference analysis on the intensity and the intensity under normal state, so as to calculate the pressure applied by the object.

Specifically, the pressure sensing method of the infrared touch screen based on surface deformation comprises the following steps:

step S: and recording the sampling intensity values of all the light paths of the touch screen in the non-touch state.

Step D: when the touch surface is touched, recording the intensity values of all light paths which do not pass through the touch point and are within a certain range from the touch point, calculating the difference value between the intensity values of the light rays and the intensity values of the light rays in a normal state, and then carrying out weighted average on the difference value of the light rays according to the distance from the touch point.

Step F: and carrying out table lookup through the coordinate positions of the touch points and the obtained weighted average value, and carrying out fuzzy matching to obtain the corresponding pressure.

It should be noted that in step F, the table stores the mapping relation of weighted averages of different pressures at each position on the surface of the touch screen, and the table can be generated through actual measurement record, or can be generated through calculation by establishing a glass pressed physical deformation model and a loss model of light propagation on different shapes of surfaces.

Example 1: assuming W is the width of the touch screen, H is the height of the touch screen, and N is the force (in newtons) applied to the touch screen, we can build a three-dimensional table formed by the three parameters above:

for example: table 1 below is a comparison table of the percent change in the sampled signal strength (the percent change in the sampled model strength is the ratio of the amount of change in the sampled signal strength to the signal strength without an obstruction) obtained when a force of 10 newtons is applied at nine coordinate points of the touch screen.

TABLE 1

10 ox	W/4	W/2	W*3/4
				H/4	-13.5％	-14.3％	-13.7％
H/2	-14.1％	-15.4％	-14.2％
				H*3/4	-13.3％	-14.5％	-13.4％

Note that: 1. each point is called a real point; 2. the minus sign indicates that the strength becomes weak after pressing; 3. the plus sign indicates that the intensity becomes stronger after pressing.

The intensity at 20 application of a force is shown in table 2 below.

TABLE 2

20 ox	W/4	W/2	W*3/4
				H/4	-14.5％	-15.3％	-14.3％
H/2	-14.9％	-16.2％	-15.0％
				H*3/4	-14.2％	-15.1％	-14.1％

The resulting table was tested for each different pressure, we called a two-dimensional comparison table, and if four conditions of 5 newtons, 10 newtons, 15 newtons, and 20 newtons were tested, we could obtain 4 two-dimensional tables.

According to the data storage capacity, the distance between the real measurement points of the lookup table can be quite dense.

Every four points adjacent to each other in the left-right direction form a rectangular area.

If a touch point falls on a certain area, the change rate of the signal intensity in the coordinate in each two-dimensional table is calculated through the relative positions between the touch point and four actual measurement of the rectangle (assuming that the pressure value between four points is linear with the distance, the change rate of the intensity in the position in the table can be calculated through a formula of y=ax).

By the above steps we have obtained a one-dimensional table of sampled intensity values at 5 n, 10 n, 15 n, 20 n at this coordinate.

Then, the actual pressure value can be converted by inquiring the intensity change rate of the touch point in which interval and through a fitting formula of the intensity and newton (if the signal quantity between 5 newtons and 10 newtons changes linearly, the conversion between the intensity change rate and the pressure can still be carried out through a y=ax linear formula).

The foregoing is merely a preferred embodiment of the present utility model and is not intended to limit the present utility model in any way. Any person skilled in the art will make any equivalent substitution or modification to the technical solution and technical content disclosed in the utility model without departing from the scope of the technical solution of the utility model, and the technical solution of the utility model is not departing from the scope of the utility model.

Claims

1. The pressure sensing method of the infrared touch screen based on the surface deformation is characterized by comprising the following steps of: when the infrared touch screen applies pressure on the surface of the infrared touch screen, the magnitude of the pressure applied by the touch object on the touch surface is judged by utilizing the magnitude of a signal component formed by surface refraction in the optical path of the surface of the infrared touch screen,

the method further comprises the following step S before judging the pressure exerted by the touch object on the touch surface: recording the sampling intensity values of all light paths of the touch screen in a non-touch state;

the method further comprises the following step D after the step S: when the touch surface is touched, recording the intensity values of all light paths which do not pass through the touch point and are within a certain range from the touch point, calculating the difference value between the intensity values of the light rays and the intensity values of the light rays in a normal state, and then calculating a weighted average value of the difference values of the light rays according to the distance from the touch point;

after step D, the method further comprises the following step F: and carrying out table lookup through the coordinate positions of the touch points and the obtained weighted average value, and carrying out fuzzy matching to obtain the corresponding pressure.