JPH03156816A - Keyboard - Google Patents

Abstract

PURPOSE:To improve the static discharge resistance, increase the life, and eliminate need of dust proofing and drip proofing by separating an operation part using light from a switch part. CONSTITUTION:Light emitting elements L1-Li+5 repeat light emission at a constant short cycle (20ms, for example). Where no key switches are pushed, light from the light emitting elements is received by light receiving elements P1-Pi+5. When a key switch Kj is pushed, light from the light emitting element Li+1 is shielded by a plunger 7 of the key switch Kj, and does not reach the light receiving element Pi+1. Similarly, light from the light emitting element Li+5 cannot reach the light receiving element Pi+5. The switch Kj as an intersection of straight lines of Li+1-Pi+1, Li+5-Pi+5 is thus recognized as being depressed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to the structure of a keyboard for an operator's console, which is a man-machine section in a process control system.

[Conventional technology]

The operator's console in a process control system can be broadly divided into a display section and an operation section. Currently, most of the operation units are keyboards.

The following items are required for the keyboard:

i) High reliability.

IT) Easy to use.

To increase reliability, consider the usage environment.

Switches must have a dust-proof and drip-proof structure and have a long lifespan.

Noise resistance is required.

In terms of ease of use, the color, placement, size of the switches, etc. are major factors, but in order to avoid fatigue, appropriate strokes and clicks are essential. If you do not have both, you will have to keep pressing the button until the key-in response is confirmed and the key-in response is displayed on the display. Especially if there is no click, it is unclear at what point the key is in contact with the key, so you end up pressing it harder.

FIG. 2 shows a conventional example.

In this example, key switch 1 with a click is used.

The top surface of the key switch is covered with a sheet 2 for the purpose of dustproofing and drip-proofing. The sheet 2 has a concave and convex portion corresponding to the key switch, and the convex portion is made to be recessed when pressed. In such a structure, you can have clicks, but
I can't get a proper stroke. This is because there is a limit to the unevenness of the sheet 2 that covers the key switch, and the limit is usually about 1 m.

FIG. 3 shows another conventional example.

In this example, conductive rubber is used as a switch. The conductive rubber 11 is a printed circuit board 3 with a switch pattern.
is placed on top. The upper surface of the conductive rubber is covered with a sheet 2 intended to be dustproof and dripproof. With such a structure, it is impossible to make a stroke, and it is also impossible to obtain a click, making it the worst in terms of usability and fatigue.

In addition, in both of the previous two examples, the mechanical system of the switch and the electrical system are close to each other, making the structure vulnerable to electrostatic discharge, which is the biggest cause of malfunction of the operating section, which is also unfavorable from a reliability standpoint. . Furthermore, in the example shown in FIG. 2, there is a problem of reduced reliability due to the small size and complexity of the key switch, and in the example shown in FIG. 3, there is a problem of disconnection of the switch pattern when the print basic button is pressed.

[Problem to be solved by the invention]

The aim is to achieve both ease of use and high reliability, something that could not be achieved with conventional keyboards.

Specifically, in addition to obtaining appropriate strokes and clicks,
The object of the present invention is to obtain a keyboard that is dustproof, dripproof, and has a structure that is resistant to static electricity.

[Means to solve the problem]

By separating the operation part and switch part using light,
The design aims to improve resistance to electrostatic discharge, extend the lifespan by eliminating contact parts, and eliminate the need for dustproof and drip-proofing because the only parts that are actually operated are the mechanical system.

The method of detecting ON10FF of the switch using light is the same as the method used for general touch switches. The operating section has a plunger that blocks light for each key, which is normally located in a position where it does not block light due to the force of a spring, etc., and is moved to a position where it blocks light only when the corresponding key is pressed. Light is output from two directions, vertically and horizontally, one light-emitting element and one light-receiving element are placed opposite each other, and each key is arranged so as to be located at the cross point of the light in the vertical and horizontal directions.

Each key also provides a mechanism for obtaining clicks.

[Effect]

Light-emitting elements and light-receiving elements arranged in the same manner as the key arrangement (for example, if the key arrangement is 10 vertically and 3 horizontally, the light-emitting elements are 10 vertically and 3 horizontally, and the light-receiving elements are also 10 vertically and 3 horizontally. Moreover, the keys are arranged on a straight line connecting the light emitting elements and the light receiving elements), and the light emitting elements emit light continuously or periodically. Further, the light receiving element receives light from the light emitting element. When no key is pressed, there is nothing blocking the light from the light emitting element, and all light is received by the light receiving element. When any key is pressed, light from the correspondingly arranged vertical and horizontal light emitting elements is blocked and no light reaches the light receiving element. This allows it to be detected which key has been pressed. By detecting that a key is being pressed using the structure that moves the key in this way, an appropriate stroke can be obtained.

〔Example〕

An example is shown in FIG.

This keyboard has a key arrangement of 3 columns vertically and i+2 columns horizontally.

The light emitting elements are L1 to L++5, and the light receiving elements are P1 to Pt.
+5. A light receiving element P1 corresponds to the light emitting element L1.

The structure of the keyboard is as follows.

A plurality of key switches 1 are attached to a hold plate 5.

Each key switch can be operated in the vertical direction, and is fixed upwardly by the force of the spring 12 unless a pushing force is applied from above. or.

Each key switch has a plunge 7 on its lower side.

The length of the plunger is adjusted so that it does not block light from the light emitting element when the key switch is not pressed, and blocks light from the light emitting element when the key switch is pressed down. Further, a click mechanism 6 is provided in the middle of the plunger 7 so that a click can be obtained. The click mechanism has a protrusion attached to a part of the plunger, and the protrusion pushes the spring.

A printed circuit board 8 on which a light emitting element and a light receiving element are attached is arranged outside the series of key switches.

The positional relationship between the light emitting element and the light receiving element is such that the center of the plunger of the key switch is on a straight line connecting the two.

Due to the structure described above, the key switch itself does not have an electrical circuit. Further, no electric circuit is arranged below the key switch group.

Explain the operation.

The light emitting elements L1 to L L+IS have a certain short period (for example, 2
0m5), the light is emitted repeatedly. When no key switch is pressed, light from all the light emitting elements is received by the light receiving elements P1 to P1+Is. key switch K
Consider the case where J is pressed. The light from the light emitting element L i+1 is blocked by the plunger of the key switch KJ and does not reach the light receiving element P1+1.

Similarly, the light from the light emitting element L+÷5 also does not reach the light receiving element Pt+6. Therefore, L1+1~Pt÷11 L1+5~
It is recognized that KJ, which is the intersection of both straight lines of P t's, is being pressed.

Note that the control circuits, such as the circuit that controls the light emission of the light emitting element and the circuit that determines whether or not light is received by the light receiving element, may be installed on the printed circuit board 8 on which the light emitting element and the light receiving element are mounted, or may be installed on the printed circuit board 8 on which the light emitting element and the light receiving element are mounted. It is also possible to place it outside.

As is clear from this example, there is no electric circuit in the lower part of the key switch group, so there is no need for a drip-proof structure6.Also, since there is no electrical contact part in the key switch, there is no need for a dust-proof structure. Further, the key switch that is actually operated by a person and the electric circuit can be made non-contact, and resistance to electrostatic noise can be improved.

In this example, the plunger for blocking light is usually long enough to not block light when the key switch is not pressed, but the length is not a concern as long as the same function can be achieved in terms of shape.

〔Effect of the invention〕

According to the present invention, it is possible to obtain a keyboard with appropriate strokes and clicks that does not require a dust-proof or drip-proof structure.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an embodiment of the present invention, and FIGS. 2 and 3 are diagrams showing a conventional example. DESCRIPTION OF SYMBOLS 1...Key switch, 4-way case, 5...Hold plate, 6...Click mechanism, 7...Plunger, 8...
...Printed circuit board, 9...Light emitting element, 10...Light receiving element, 12...Hanging 1 Funeral diagram

Claims (1)

[Scope of Claims] 1. A keyboard of an operator's console of a process control system, in which a light emitting element and a light receiving element are arranged in positions surrounding a group of arbitrarily arranged key switches, and the light emitting element A key switch is arranged on a straight line (light path) connecting the light emitting element and the light receiving element of each set, and the key switch is placed along at least two of the straight lines. They are arranged in a straight line, and each key switch has a plunger so that when the key switch is not pressed, the light from the light emitting element is not blocked, and when the key switch is pressed, the light from the light emitting element is blocked. A keyboard, characterized in that the position of a pressed key switch is detected by blocking light from the light emitting element at two places. 2. In item 1, by alternately arranging the light-emitting elements and the light-receiving elements, two light-emitting elements and two light-receiving elements are controlled as one set, thereby reducing the influence of light leakage between the light-emitting elements. A keyboard that features: