CN1061090A - Displacement detection method and device using light sensing method - Google Patents

Abstract

The invention relates to a displacement detection method and device by adopting a light sensing mode, the device mainly comprises a coordinate grid plate 11 with a vertical and horizontal coordinate line and a machine body which moves on the coordinate grid plate and contains an optical element and a light sensing element, and the principle is as follows: the light source 10 irradiates the coordinate grid plate, the imaging lens 12 enlarges the fine scales on the coordinate grid plate, the light is focused and focused on the vertical and horizontal optical sensing elements 14 and 16 by utilizing the condenser lenses 13 and 15 or the reflector on the imaging surface respectively, and the axial displacement information of X, Y is directly obtained by the output signals of the optical sensing elements. The method and the device are simple and have high accuracy.

Description

The invention relates to a displacement detection method and device, in particular to a displacement detection method and device using light sensing.

Displacement detection technology in two-dimensional space has been used in industrial control and computer input and input devices for many years, and it has become a must-have. The precision of the corresponding devices has always been pursued and flaunted by the business community. Taking the increasing popularity of computers as an example, the human-machine interface of the system has gradually abandoned the traditional keyboard input method, and uses the hand to move on the board to cooperate with the window. (WINDOW) software to complete the computer cursor (CURSOR) control and the way to issue operation instructions. Devices and software that realize this function are not only showing their power in computer-aided design (CAD) and drawing software, but also in business, education, family, and even entertainment software. The reason is that such devices can be used in It is more economical, practical and convenient to use.

The existing commonly used devices mostly adopt the mechanical friction transmission mode. There are two sets of encoders (ENCODER) in the X and Y axes in the moving body. The encoder is a standard rotary encoder (ROTARY ENCODER). The transmission shaft is directly connected to the plate. Surface friction, or transmission by a sphere; during displacement, the encoders in the X and Y axes are used to give displacement information. But these technologies have many congenital and acquired defects, because it must possess multiple transmission mechanisms, its structure is complex, and its mechanism configuration must be quite precise.

As we all know, rotation will cause friction, and if there is friction, there will be gaps and some errors. Therefore, the accuracy of this friction transmission device will naturally decrease. Furthermore, any material will be worn out, causing its error value to increase with the number of times of use. Even if the problem on the mechanism is overcome, the transmission shaft or the ball will carry the dust and dirt on the plate surface to the internal mechanism during use, causing Frequent cleaning and maintenance are required, and in severe cases, it is even completely inoperable, causing a major problem in use.

Apparently, the design and manufacturing methods of the known similar devices really need to be updated with better methods to break through. The inventor finally produces the present invention with years of experience in the use and design of similar devices, and after repeated experiments and improvements.

The object of the present invention is to provide a displacement detection method and device thereof with simple structure, frictionless transmission, high precision and high resolution.

The displacement detection method adopting the optical sensing method of the present invention mainly realizes the purpose of the invention in the following manner: a body and a specific coordinate grid plate do a relative displacement movement, project a light source onto the coordinate grid plate to generate an image, and utilize After the imaging lens magnifies the image, the light is collected by condenser lenses or reflectors in different axes, and the light sensing element converts the collected light in each axis into an electrical signal representing the displacement state.

In addition, the way to collect the light source is to use lenses or reflectors, or use both of them in an interactive manner. The light source is located on the same side or another side of the grid relative to the light sensing element. The distance from the coordinate grid to the center of the imaging lens is smaller than the distance from the center of the imaging lens to the imaging plane, and its magnifying effect on the image is used to improve the resolution. The coordinate grid is reflective or translucent. The vertical and horizontal coordinate lines on the surface of the coordinate grid are of equal width and the line width and line spacing are equal.

The displacement detection device adopting the optical sensing mode of the present invention mainly realizes its object of the invention in the following ways:

A coordinate grid made of reflective or light-transmitting material, marked on its surface with vertical and horizontal markings of equal width, and the line width and line spacing are equal;

1. The body that makes relative displacement with the coordinate grid;

A light source installed in the body or on the other side of the coordinate grid corresponding to the reflective or light-transmitting grid;

An imaging lens arranged in the body to magnify the coordinates of the coordinate grid;

A group of condensing lenses or reflectors arranged in the body and on the imaging plane of the imaging lens to focus the rays from different axes of the imaging lens respectively;

The light sensing element is arranged in the body and at least one-to-one corresponding to each condensing lens or a reflecting mirror.

In addition, the condensing lens or reflector is in the shape of a rectangle, and the lenses or reflectors on the same axis can be arranged adjacent to each other or separated by a distance between a marking line.

General physical knowledge about optical light that can be guided, gathered, and diffused by lens refraction and mirror reflection, etc., is not going to be repeated here, and the known accessories necessary for any electrical equipment, such as power supply and signal transmission wires, Wait, I won't go into details here.

The technical means, elements and functions used in the application and implementation of the present invention will be described in detail below with examples and associated drawings.

The description of the accompanying drawings in the manual is as follows:

FIG. 1 is a schematic diagram of the present invention when a condenser lens group is used.

Fig. 2 is a cross-sectional view of the present invention when a condenser lens group is used.

Fig. 3 is a partially enlarged top view of the coordinate grid of the present invention.

Fig. 4 is an enlarged schematic view of the focusing area of the present invention.

FIG. 5 is a diagram illustrating the variation of the uniaxial displacement signal of the present invention.

FIG. 6 illustrates the variation of the biaxial composite displacement signal of the present invention.

Fig. 7 is a schematic diagram of the present invention when a mirror group is used.

Fig. 8 is a cross-sectional view of the present invention when a mirror group is used.

Fig. 9 is an application design example 1 of the present invention.

Fig. 10 is the second application design example of the present invention.

As shown in Figure 1, when the present invention uses a condenser lens, its main components include a light source 10 (or 10'), which is mainly used to project on the coordinate grid 11, and its color, wavelength, material, shape, etc. are not special Requirements, this example takes the commonly used light-emitting diode (LED) as an example. The coordinate grid plate 11 used in the present invention can utilize reflective plate to print coordinate grid, or use light-transmitting materials such as film, glass and print coordinate grid on its surface to realize, when coordinate grid plate uses reflective material , the light source 10 is fixed in the body 20 and projects into the object image area of the imaging lens 12 . The imaging lens 12 is an imaging mirror, which has better light-gathering performance, and can gather incident light from any direction in front of the lens to the center, and form an image at the rear of the imaging lens 12 .

After passing through the imaging lens 12, the light can be imaged on the sections 13, 13', 15, 15', according to the optical magnification M (magnification) = P (image distance) / S (object distance), let P (i.e. imaging The distance between the surfaces 13, 13', 15, 15' and the center of the imaging lens 12) is greater than the object distance (that is, the distance from the center of the lens to the surface of the coordinate grid 11), and accordingly, the scale of the coordinate grid can be enlarged. As shown in Fig. 3 and Fig. 4, the oblique line area 17 is the shadow of the coordinate scale line, and the blank area 18 is the interval of the coordinate scale line, which is formed by the light source 10, 10' projection, and the coordinate line width and interval can be adjusted. Set to completely equal width, and the image areas covered by rectangular condenser lenses 13, 13 ' and 15, 15 ' are designed as shown in Figure 4, the condenser lenses of the same axial direction can be arranged adjacently, or can be One block apart. The area covered by each condensing lens is now defined as the "light-collecting surface", and the focus of each condensing lens must correspond to more than one light sensing element. As shown in Fig. 1 , the condenser lenses 13, 13' focus all the light on the light-collecting surface they cover to the light sensing elements 14, 14', and the lenses 15, 15' focus on the elements 16, 16'. It can be seen from the focusing situation shown in FIG. 4 that the light sensing elements 14, 14', 16, and 16' have no bright spots or only very small bright spots on their corresponding light-collecting surfaces 13, 13', 15, and 15'. Part of the light-collecting surface has bright blocks. If the surface does not receive any light or the light is too weak, at this time, its output is defined as a "0" signal, and the light-sensing element 16' has a 1/1 2 is irradiated by light, and thus can change the state of the light sensing element 16', which is defined as a "1" signal.

As shown in Fig. 2, in the embodiment that the present invention adopts condensing lens, imaging lens 12, condensing lens group 13,13', 15,15' and light sensing element 14,14', 16,16' are connected with electronic Necessary components 19 such as circuits and wires 21 are all assembled in a body 20, so that the body 20 and the coordinate grid 11 are separated into two independent bodies. When there is a relative displacement between the body 20 and the coordinate grid 11, the object image in front of the imaging lens 12 must change. Therefore, the relationship between the light-collecting surface and the coordinate grid bright and dark images shown in FIG. 4 must also change. , now give a detailed description of the displacement in the X-axis direction.

Figure 5 shows the displacement detection principle of the present invention when performing uniaxial displacement. Only horizontal (X-axis) displacement is performed between the machine body 20 and the coordinate grid 11, and sequentially generate A, B, C, D, etc. Signal, during which or for the body 20 to move to the right, or for the coordinate grid 11 to move to the left.

According to the above, the light and dark images received by the light sensing element are defined as 1, 0 signals, then when the light collecting surface 13, 13' is displaced, the following signal combination can be obtained from the light sensing element 14, 14', if the displacement changes In order to change from state A to state B, its combination changes from [0, 0] to [0, 1], and so on, if it continues to shift to the right from state D, it returns to state A, and changes to Periodic relationship, after sorting and arranging its combined state, the following relationship can be obtained:

This combination relationship is the output signal of a commonly used standard displacement detector. It must be noted that at this time, the machine body 20 or the coordinate grid 11 is only displaced in one axis, and the other axial state will not be affected by this movement.

When the body 20 and the coordinate grid 11 have displacements in the X and Y axis directions, as shown in Figure 6, the body 20 from state E to state F can be known as a displacement of one unit (UNIT) to the lower right. The combination of output signals in the X-axis direction changes from [0, 1] to [1, 1], and the combination changes from [1, 1] to [1, 0] from state F to state G; at the same time, the combination of output signals in the Y-axis direction is changed from [0, 0] changes to [0, 1], and its combination changes from [0, 1] to [1, 1] when state F changes to state G. At this time, the simultaneous detection status of the light sensing element can be known from the output signals in the X-axis and Y-axis directions.

Another embodiment of the present invention is to use reflectors to condense light, as shown in Figures 7 and 8, its operating principle is exactly the same as the above-mentioned embodiment, and also includes a light source 30 or 30', a coordinate grid 31, a lens 32, The light sensing elements 34, 34', 36, 36', the circuit elements 39, and the body 40, except that the condensing lens is changed into the arched reflectors 33, 33', 35, 35' here.

Because the light can be deflected to any direction by both the condenser lens and the reflection mirror, so the present invention does not have any restrictions on the combination shape when applied, such as the combination of an axial condenser lens and an axial reflection condenser lens, or For other similar combinations, there are as many as 16 combinations (4 ² ). When the lens focusing method is used, the imaging area is on the top, which is more suitable for vertical or elongated designs. Figure 9 is an example of this type of application; When concentrating light, a slightly larger cross-section is required, and it is more suitable for a horizontal design. Figure 10 is an example of this form of application.

After the image of the coordinate grid 11 is enlarged, it is then focused on the light sensing element by a condenser lens or a mirror. Considering the economic cost, in practice, the light sensing element can be a phototransistor (PHOTO-TRANSISTOR) or a photodiode (PHOTO-DIODE), and its actual light-receiving area is generally only about 20 mil (MIL) square, if the magnification of the image is 2, the enlarged line width (to cover the width of two condenser lenses or reflectors) only needs to be 20 mils, that is, the coordinate line width on the coordinate grid is 10 mils, and the interval is also 10 mils. Mill, in this way, there can be 1000/20=50 (about 20/cm) coordinate lines per inch, because 4 points (COUNTS) can be detected between the coordinate lines and the coordinate lines, so it is Designed to achieve an accuracy of 200 dots (D, P, I) per inch (about 79 dots/cm), if the optical magnification is 12, it can reach 1200 dots (about 472 dots/cm), which is very accurate , which is almost impossible to achieve precisely by commonly used displacement detectors. It is particularly worth noting that the coordinate grid is not particularly fine, and it can be made without special manufacturing technology. If you want to make a fine scale on the coordinate grid, with the current industrial technology level, use evaporation or photosensitive method can be achieved.

The method and device provided by the present invention have the characteristics of simple structure, high precision and high resolution; more importantly, the output provided by the present invention is the output of the existing standard displacement detector, but without any complicated and time-consuming calculations , will not reduce the response speed of the displacement detector. It is an invention with great practical value.

Obviously, the present invention can be designed in various transformations without departing from its basic spirit, that is, the implementation of the present invention should exceed the implementation mode described in detail above. Should be included in the patent application scope of the present invention.

Claims (8)

1, a kind of displacement detecting method that adopts the light sensing mode, it comprises: a body and a specific coordinate lattice plate are done the relative displacement campaign, light source projects is produced image to coordinate lattice plate, after utilizing imaging len that image is amplified, through disalignment to collector lens or catoptron make light-ray condensing, collected light each is axial by light sensing element is converted to the electric signal of representing displacement state.

2, displacement detecting method as claimed in claim 1 is characterized in that: the mode of described gathering light source is for utilizing lens or catoptron, or both are mutual simultaneously uses.

3, displacement detecting method as claimed in claim 1 is characterized in that: described light source is positioned at the same side or the opposite side of coordinate lattice plate with respect to light sensing element.

4, displacement detecting method as claimed in claim 1 is characterized in that: described coordinate lattice plate to the distance at imaging len center less than the distance of imaging len center to imaging plane, improve resolution with its amplification to image.

5, displacement detecting method as claimed in claim 1 is characterized in that: described coordinate lattice plate is reflecting type or Nonopaque type.

6, displacement detecting method as claimed in claim 1 is characterized in that: the vertical and horizontal base graticule on described coordinate lattice plate surface equates with distance between centers of tracks for waiting width and live width.

7, a kind of displacement detector that adopts the light sensing mode, it comprises:

-by have reflective or light transmissive material is made, the vertical and horizontal graticule of width such as its surperficial marking and the coordinate lattice plate that live width equates with distance between centers of tracks;

-do the body of relative displacement with coordinate lattice plate;

-be located in the body corresponding to the coordinate lattice plate of reflective or printing opacity or the light source of the another side of coordinate lattice plate;

-be located at the imaging len that amplifies in order to coordinate in the body with coordinate lattice plate;

-be mounted in the body and be positioned at the imaging plane of imaging len, in order to will from the disalignment of imaging lens to the light collector lens or the catoptron that focus on respectively;

Be located in the body and at least with each collector lens or catoptron light sensing element one to one.

8, displacement detector as claimed in claim 7 is characterized in that: described collector lens or catoptron are rectangle, and same axial lens or catoptron can adjacent arrangements or at a distance of the distance of a graphed lines spacing.

Images