JPS59139519A - Reflecting photoelectric switch - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [B Technical Field] The invention relates to a reflective photoelectric switch that determines whether a detected object exists within a preset detection area and controls an output circuit. It is something.

[Background technology]

Figures 1 and 2 show the basic side of this type of reflective photoelectric switch. It is an optical means and includes an oscillation circuit (1o) that generates a synchronization signal that sets the light emission timing, a drive circuit (II), and a light emission element (I) such as a light emitting diode or a laser diode.
2) and a projection optical system (13) consisting of a condenser lens that forms a light beam (P). (2
) are juxtaposed at a predetermined distance lO from the light projecting means fi).
The light receiving means +1) and the light receiving means (2) are arranged in a triangular manner with respect to the detected object (2). This light receiving means (2) is provided with a light receiving optical system (3) consisting of a convex slit for collecting the light reflected by the object to be detected (X), and a light collecting surface of the light receiving optical system (3). Expression, condensing spot (S
position detection means () that outputs a position signal corresponding to the position of
This position detection means (4) is composed of δn and 291.
A light-condensing spot t arranged within the light-converging plane of the light-receiving optical system (3)
- It is formed of 21 light receiving elements (20a) (20b) arranged in series in the moving direction (arrow M) of (S). As the light receiving elements (20a) (20b), phototransistors, photodiodes, solar cells, CdS, etc. are used. (5) is a discrimination control means, which detects a wave detection object flash based on the output of the position detection means (4) in a predetermined detection area (
DE) and outputs the output image path (6).
). This discrimination control means (5
) consists of a light receiving circuit (21a) (21b) that amplifies the output current IB from the light receiving element (20a) (20b) to a signal voltage VAXVBK, and a logarithmic amplification circuit (22a) (
22b) and the logarithmic amplification circuit (22a) output log VA
A subtraction circuit 123) that subtracts the output log VB of the am width circuit (22b) from the subtraction circuit (n51 output log V
A/VB and detection area setting volume (VR)? The subtraction circuit is +23 by comparing it with the 6 masterpiece level Vs that was created.
) Output] ogVA/vB operates and the key is below Vs ■
(comparison circuit that outputs level) and light emitting element (12)
The light beam (P) is emitted from the oscillator circuit (1
The comparison circuit g4 is synchronized with the synchronization signal output from
If you link the 1st output, it will become a smart proboscis C.
The signal processing circuit 120 is configured to reliably determine whether or not the
It controls an output circuit (6) consisting of a semiconductor switch element for load control XI. Note that the light receiving circuits (21a) and (21b) include a bassid pass filter circuit that passes only the pulsed optical signal and cuts the DC optical signal, or passes only the frequency of %.

Now, as shown in Fig. 3(a), the detected object (A) is at a distance of Jlias lb from the reflective light heavy switch (Y),
When the positions a4, b, and cK of llc exist, the positions of the condensing spots (S) with respect to the light receiving elements (20a) (20b) arranged in the condensing plane are as shown in Fig. 3 (b).
), and when the object to be detected) moves in the direction of the light beam (P), the condensed beam (S) moves in the direction of arrow N1 and hits the light receiving elements (20a) (20b). The ratio of the amount of incident light changes, and the light receiving element (20a)
The output currents IA and IB of (20b) are the focused spot (S
) is a position signal corresponding to (M iW ).The discrimination control means (5) forms heavy pressures VA, VB proportional to the currents IA, IB in the light receiving circuits (21a) (21b),
Logarithmic amplification circuit (22a) (221)) Reduces the pressure in the stomach (log VA, log VB) due to VC
By subtracting by the circuit (subtraction circuit 123), the logarithm 1 log VA/VB of the ratio of the amount of light incident on the light receiving element (20a) (20bl) is outputted. 23) Output 10g VA/
VB changes according to the movement of the detected object (3), and the subtraction circuit for the distance l from the reflective photoelectric switch (■) to the detected object (A) (drowning output Iog VA / Vl+ is as shown in Figure 4) Therefore, the operating level (Vs
), it is necessary to set the accurate detection area (D
E) can be easily set, subtraction circuit 123) output log
When VA/VB becomes equal to or higher than the operating level vs, the output of the comparator circuit (24) becomes H level, and the output circuit (6) is activated via the signal processing circuit (c). In this case, the discrimination control means (5) selects the light receiving elements (20a) (20b).
The level ratio of the output is calculated, and the level ratio is set in advance.
The output circuit (6) is activated when the operation level Vs is the same, and the reflected light (R
), the detection area (DE) is set regardless of the level of A detection area (DE) is set regardless of the light reflectance of the object 00, and an optical system L1 for emitting and receiving light is set.
3) It is designed not to be affected by +31 contamination.

By the way, in such a basic example, the resolution, that is, the setting accuracy of the detection area (DE) is different from that of a reflective photoelectric switch (
The distance from Y) to the detected object flash <a varies depending on
There has been a problem in that the farther the object to be detected (3) is, the worse the resolution becomes. Toe 9: The condensing spora I-(S) moves in the direction of arrow M on the light receiving element (zoa) (20b) in accordance with the movement of the object to be detected (3), but the movement of this condensing spot (S) The distance X is inversely proportional to the distance l to the detected object (I = fodo k). However, f is the distance between the light-receiving optical system (3) and the light-receiving elements (20a) (20b), and f-lo is a constant. As is clear from the above equation, the moving distance X of the focused spot (S) is the distance 4
The larger the value, the smaller it becomes, and the resolution becomes worse. However, there is a problem in that the incident light on the light receiving elements (20a) (20b) is very different when the detected object (a) is close and when it is far away, and the discrimination control means (5) may malfunction. there were. That is, the light receiving element (20a
) (20b) The amount of light received (only the reflected light from the object to be detected (3)) is inversely proportional to the square of the distance, so if the distance l is 3Qyrtytr~3 (n is the light receiving element The amount of light incident on (20a) (20b) is 1
It changes by about 0.02. On the other hand, if the light reflectance of the object to be detected (3) is taken into consideration, the range of change in the amount of light incident on the light receiving elements (20a) (20b) will be approximately 105, but the dynamic precision of the discrimination control means (5) will be Since it is not possible to take a large margin, there is a problem in that the detection area (DE) cannot be set over a wide range from close range to long range.

[Purpose of the invention]

The present invention was developed in view of the above points, and the light receiving means is arranged in a triangular manner with respect to the object to be detected, and the light receiving means is placed on the light converging surface of the light receiving optical system at a certain position. A reflective photoelectric switch in which a detection means controls an output circuit by determining whether a detected object exists within a predetermined horizontal area based on the position If1g corresponding to the position of a condensed spot. , the detection area can be set over a wide range from short distances to long distances.

[Disclosure of the invention]

(Embodiment 1) FIG. 5 shows an embodiment of the first invention, in which the position detection means (4) in the basic example shown in FIGS.
Instead, a position detecting means (4a) is used in which the light receiving elements (20a) (20b) are arranged in series in a direction perpendicular to the moving direction (arrow M) of the focused spot (S).
20a) (20b) Kensuke line) is the condensing spot (S
), and when the detected object (X) moves and the focused spot S) moves in the direction of arrow M, the difference in light receiving area of both light receiving elements (20a) (20b) is continuous. Adjust the upper 1st line (E) to the focusing spot (S) so that it changes.
) in a direction perpendicular to the moving direction (arrow M). Here, the displacement of Sakai line (ji) is the distance l
Set so that the amount of change in the light-receiving area ratio of the two-party optical elements (20a) (20b) with respect to the moving distance The light-receiving area ratio of both light-receiving elements (20a) (20b) when they are close together (for example, position ia in Figure 3(a)) is slightly reduced, and the ratio of the light-receiving areas of the two light-receiving elements (20a) (20b) becomes smaller (and therefore (for example, at position ia in Figure 3(a)). , c), the light receiving area ratio of both light receiving elements (20a) and (20b) is set to gradually increase.In other words, the moving distance I of the condensed spot (S) is
= 1, and if this is represented by j rough, it will be as shown in Fig. 6. By the way, it is possible to increase the level ratio of the outputs of the light receiving elements (20a) (20b) and change the area of the elements (20a) (20b) in the part where the moving distance X of the focused spot (S) is small. It turns out.

(Effect of the first invention) As described above, in the first example, the
When the object to be detected moves in the projection direction of the light beam, the position detection means is composed of two light receiving elements arranged in series in a direction perpendicular to the direction of movement of the condensed spot when the object to be detected moves in the projection direction of the light beam. When the level ratio of the light-receiving element output reaches a preset value, the output circuit is set to ff. When the line position is changed to 1d and the focused spot moves due to the aid of the object to be detected, the fluorescence of both light receiving elements in 3.
/l, so that the area changes continuously (by appropriately displacing the boundary line in the direction perpendicular to the moving direction of the focused spot, and the distance to the detected object increases This method has the advantage that it can be used to avoid deterioration of resolution, and that the saving area can be set accurately over a wide range from short distances to long distances.

(Embodiment 2) FIG. 7 shows an embodiment of the second invention, in which the position detection means (4) in the basic example shown in FIGS.
1N, a position detection means (4b) is used in which the light receiving elements (20a) (20b) are connected to the moving Wl force rotation (arrow M) of the focused spot (S), and the detected object ( Focused spot (S) when the illusion moves in the direction of approaching
Due to the movement of
) is provided with a light-receiving area lI timer stage to reduce the light-receiving area. In FIG. 7(a), the light receiving element (20a)
By applying a mask (30) to the top surface of (20b), a predetermined light-receiving surface area is obtained for the moving distance X of the condensing spots 1 to (S'l), as shown in FIG. 7(b). In (c), the t'L light-receiving resistors (20a) and (20b) are each formed into a shape with notches 3 at the ends so that a light-receiving area of -CJ-yri can be obtained.

Now, in the second embodiment, the amount of light received is corrected by changing the light receiving area with respect to #auxiliary distance X of the focused spot (S).
When the detected object (X) is close, the light receiving area for the condensed spot (S) is reduced, and the detected object (3)
If it is far away, do it by listening to all the dog's results.'J? 9. Light receiving element (20a
) (20b) becomes small, so when the three-tiner range of the light receiving circuit (21a) (21b), logarithmic amplification circuit (22a) (22b), etc. of the discrimination control handle (5) is small, Also, if the detection area (DE) is set over a wide range from short distance to long distance t4t, 18IT syndrome will occur. Here, the light receiving area is changed based on the curve 72 and the curve □, which is symmetrical with the straight line A as the axis of symmetry (A-2
m)2n is the change in the amount of light received due to the distance β, which is equal to K+P.

(Effects of the second invention) As described above, the second invention provides a light-condensing spot that can be disposed within the light-converging plane of the light-receiving optical system, and when the object to be detected moves in the projection direction of the light beam -6. The position detecting means is composed of two light receiving elements connected in the direction of the moving force, and an output circuit is created when the level ratio of the outputs of both light receiving elements is at a preset operating level. The discrimination control means is configured so that the object to be detected approaches the object, and the light reception limiting means is provided so that the light receiving area of both light receiving elements becomes smaller due to the movement of the condensed spot when the object to be detected moves in the approaching direction. e, the amount of light received by the light receiving element decreases as the familiar object approaches, and the difference in the amount of light received by the light receiving element due to a change in the distance 4 to the object to be detected becomes smaller, so the determination control means is adjusted; : Even if the 7-axis is equipped with a small device, it has the advantage that the detection area can be set over a wide range from close range to long range.

[Brief explanation of the drawing]

Figure 1 is a diagram showing the configuration of a basic example according to the invention, Figure 2 is a circuit diagram of the same as above, Figures 3, 4 and 4 are explanatory diagrams of the previous work of the same, and Figure 5 is the same as the invention. A top view of the main parts showing the operation and configuration of one embodiment, FIG. 6 is an explanatory diagram of the previous work, and FIG.
Figures (a) (b) (C> are top views of the narrow part of other embodiments,
FIG. 8 is an explanatory diagram of the previous work of the same as above. (1) is a light projecting means, (
2) is a light receiving means, +3) is an optical system for ID light receiving, (4) is a position detecting means, (5) is a discrimination control means, (6) is an output circuit, and (20a) and (20b) are light receiving elements. Agent Masu Burier Ishi 1) Ai 7 Figure 5 Figure 6 m 1-

Claims (1)

[Claims] (]) Light projecting means for projecting a light beam onto an object to be detected; A light-receiving optical system that collects light, a position detection means that is disposed on the light-collecting surface of the light-receiving optical system and outputs a position signal corresponding to the position of the light-condensed spot, and a position detection means that outputs a position signal corresponding to the position of the light-condensed spot; In a reflective photoelectric switch, the reflective photoelectric switch is provided with a discrimination control means for discriminating whether or not an object exists within a detection area and controlling an output circuit, and disposed within a light condensing surface of a light receiving optical system. When the object to be detected moves in the projection direction of the light beam, two light-receiving elements arranged in series in a direction perpendicular to the direction of movement of the focused spot constitute the -C position detection means.
, the discrimination control means is configured to operate the output circuit when the level 1 ratio of the outputs of the two light receiving elements is at a preset operating level, and the line between the two light receiving elements is positioned within the locus of the focused spot. The boundary line is appropriately displaced in a direction perpendicular to the direction of movement of the focused spot so that when the detected object moves and the focused spot moves, the light receiving area of both light receiving elements changes continuously. (2) A reflective photoelectric switch characterized by comprising: a light projecting means for projecting a light beam onto an object to be detected; a light-receiving optical system that collects the reflected light beam from the object to be detected; a position detecting means that outputs a position signal corresponding to the position of the light-converging spot disposed on the light-converging surface of the light-receiving optical system; A reflective photoelectric switch comprising a discrimination control means for determining whether a detected object exists within a predetermined detection area based on the output of the detection means and controlling an output circuit. Position detection means using two light-receiving elements arranged in a plane and connected in the direction of movement of the condensed spot when the test subject 51'I'I's proboscis moves in the direction of projection of the light beam. At the same time, the discrimination control means is configured so that the m-force circuit can be operated when the level ratio of the outputs of both light receiving elements is at a preset operating level. A reflective photoelectric switch characterized by being provided with a light receiving limiting means that reduces the light receiving area of both light receiving elements by moving a focused spot.