Illuminated pushbutton with colors and brightness electronically controlled

The invention relates an illuminated pushbutton with variable color lights electronically controlled, where the light is emitted utilizing solid state devices. Momentary action or alternate action switch is realized without electromechanical commutation. "Momentary action" means the generation of an electrical or electronic signal for all the time the button is maintained active. "Alternate action" means the generation of an electrical or electronic signal which changes the state each time the pushbutton is pushed. The illuminated part consists of a display which can be divided in independent zones, illuminated with visible light, generated inside of the button, having any wave length programmable in an operative, semi-operative or fixed way, independently for each zone. The zones can be of any number.

The pushbutton described in the following is the version divided in four zones.

The invention lies in the field of the electronic devices and can find application where it is necessary dispose of command/control illuminated pushbuttons; in mechanical, electrical and electronic equipments. It can be used in any operative ambient. Regarding naval, avionical, space fields, it must underline that the invention has the requirement to be used in said sectors, for instance, said pushbutton can support any stress even when the device is in operation.

The invention represents a new step in the planning and realization technique of the control pushbutton: the display light is obtained by a solid state components. The pushbutton configuration is such that the zones can be colored with one of the wished colors, and these colors can be electrically changed depending on the user needs.

The push buttons known until now in the market, at least known by the inventors, are constituted by switch and display, but the switch generally is mechanical and then the commutations number has a limited life of mechanical parts, for instance with mechanical contacts and springs. Mechanical and electrical bounces of commutation are unwanted negative effects.

Such effects generate false signals to be eliminated by electronic stratagems.

Until now in such pushbutton, the part activated by the operator, is illuminated by lamps which generate a base light similar to the white and to obtain different coloration, filters and optical corrections are employed. Said lamps do not allow to generate changes in the emitted light coloration, but only the light emission in a color or missing light. In this way the base requirement, necessary for the operative application which is to dispose with a display always illuminated with light which can change color and brightness, is not obtained.

For instance, operative rules and the human engineering prescriptions require for operative readout of any information the use of lighting of different coloration and brightness in dependence on the operative meaning of the same. For instance, white light to permit the reading of the information and the identification of the command by the operator; red light to readout alarm states and variable lighting (green, blue, amber, etc) depending on the operative conditions.

Lamps have a limited operative life, because of their employing needs a frequent access into the internal parts of the illuminated pushbutton for the replacement of the failed lams. With the necessity of active maintainability plan.

To verify the presence of failed lamps it is necessary to implement the lamp test function that the operator activates using a specific command. The off state of the lamps, creates ambiguity between the condition of failed lamps or lamps deactivate state.

The inconveniences above described are overcome by the illuminated pushbutton, as here below described:

• the pushbutton has a display made of solid state components able to supply light, for instance leds, in the colors, red, green and blue, by mixing them; any light color in the visible light spectrum can be generated without using filters. (Even the lightness can be electronically controlled).
• the color commutation and intensity are obtained electronically;
• it allows the activation of electric/electronic commutation devices, as means of conductive robber switch, solid state switch (phototransistor/photodiodes) etc.;
• it allows the carrying out of millions of operations without incurring in inconveniences caused by wear;
• the MTBF values (Medium Time Between Failure) reachable are such to eliminate any maintenance work.

This illuminated pushbutton is also created to be employed in cockpits and in command and control panels in mechanical and electric and electronic equipments.

The display illumination is one of the original aspects. It is obtained by solid state components, through which it is possible produce light of any color, even white. The display as unlimited working life, with respect to previous solutions:

• it is not necessary to curry out "the lamp test", nor the following operations of substitution of the same, as there are no lamps;
• the display is cold at the touch, even in maximum luminosity conditions.

The display is subdivided in zones, and can be illuminated independently both for luminosity and color:

• the color of each zone can be dynamically varied in accordance with their operational conditions. The possibility of change the color of the light, in a dynamically way, allows to meet any rules prescribed. It is therefore possible to illuminate any zone with white light to facilitate the legend reading and modifying thereof the writing of the background, in accordance with the rules to the modification of operative status, making it readable also in sun light ambient;
• an especial switch actuator is employed, able to control switches obtainable without mechanical contacts, for instance by conductive rubber or through solid state optical elements allowing unlimited number of maneuvers, maintaining a correct operation even in severe shock and vibration conditions.

Even if we refer to the version preferred to realize the invention, this pushbutton can change many configuration just modifying the internal electronic circuits. For instance, properly modifying the electronic circuits is obtained :

• alternate functions (bistable) of the electric contact;
• direct control throw external commands of the emitted light, control and command of the illuminated pushbutton through many kinds of serial comunications using several standard hardware and software protocols.

In fact, relatively to the version of the invention now preferred, calculated housings, to containing electronic parts of different complexity, are foreseen, including the use of an internal microcontroller, realizing the above cited functions and others required in the specific market.

An other advantage of this invention is that the illuminated pushbuttons can be applied on panels, singularly or in matrix, utilizing in this last case a proper container. The version in matrix, realizing in a firm, offers better compactness and, reduction of the space, weight, costs and a better quality for the smaller number of the parts utilized.

The input-output pushbutton connections are realized by direct coupling throw motherboards or crimp connectors.

The invention, described in the following, is the version actually preferred by the inventors, and refers to the enclosed figures.

Fig. 1 Side view of the pushbutton.

Fig. 2 Top view.

Fig. 3 Side view section.

Fig. 4 Exploited view of the display.

Fig. 5 Exploited view of the pushbutton.

Fig. 6 Some configurations of the display.

Fig. 7 Pushbutton housing for matrix assembly.

Fig. 8 Pushbutton assembly matrix configuration.

With reference to Fig. 1, the display assembly 5, constituted by a movable part 3 and a fixed part 4, includes the flange 2 for panel mounting 36 and it is united to the switch assembly 6 to constitute the pushbutton. The clamping spacer 8, clamped by the cam 9, is the contrasting element of the flange 2, used to fix the pushbutton on the panel 36 and the compression of the seal mounting gasket 11. The pushbutton is closed on the rear side by a cover 7. Also the input-output connector 10 is on this side.

With reference to the Fig. 2, the pushbutton illuminated area 1, the flange 2 and the movable part of the display can be seen.

With reference to Fig. 3, the pushbutton is constituted as follows:

• the display assembly (of which the exploited view is in Fig. 4) constituted by the display cover 12 which is mechanically connected to the housing display 13, by a mechanical latch 27, inside of which housing display optical devices 18 are enclosed. These optical devices arc transparent elements 40, a label 41, an optical diffuser 42 and all is necessary to realize any optical performance required. The reflector 14 is utilized to direct the lighting emission of the solid state elements 15. The housing display 13 includes slide guide 28 which allows that the movable element 3 of the display to shift along the actuator axis. The pushbutton gasket 20, (Figures 3 and 5), is employed to seal the pushbutton internal parts to avoid humidity or other contaminating elements in the switch 6 zone (Fig. 1). The mounting gasket 11 (which does not appear in Fig. 4) is mounted under the flange 2 to realize a seal to external agents as water, etc. The flexible circuits 16 blocked by the screw 43 and sealed in the zones 17 and 21, realizes the electrical connections between the display 5 assembly and the other parts of the pushbutton. The seal of the external agents is frontally realized by the display gasket 19. The transmission of the movement in the pushbutton is realized by the actuator support 44;
• the switch assembly (6 in Fig. 1) comprises the switch shell 51, the rear input-output cover 7, the spring guide 32, the actuator axis 31, the switch actuator 25, the spring 33, the rubber switch 24. The movement on the vertical axis, effected by the activation of the lighting pushbutton and then by the moving of the movable part display 3, moves the switch actuator 25 and then presses the spring 33 housed in the spring guide 32 activating the rubber switch 24, so realizing the switching function.

The vertical axis movement of the actuator is guided by the actuator slide guide 29. The actuator slide guide 29 and the washer 50 protect even the metallic parts, as they are in plastic material or similar, to be damaged by wear and abrasion.

The pushbutton electrical connections are realized by the flexible circuit 23 and the electronic parts 30.

The connector 22 connects the display assembly with the switch. The electronic parts are housed in the zones 26. The electric connections of the pushbutton to the external, are realized by connector/connectors 10 mounted on the flexible circuit 23.

Fig. 6 shows some of the many configurations in which the display can be realized.

Fig. 7 represents one example of matrix housing 45 for assembly single pushbutton 46 matrix installation.

The example shows a four rows-three columns matrix. It can contain so twelve single pushbutton. Each pushbutton inserts in the direction of the insertion 47 showed and when assembled, it reaches the position represented 46. Even the flange 48 of this matrix has a gasket to avoid contamination by external agents.

Fig. 8 shows a pushbutton matrix assembled during the manufacturing. It is the version with four rows and two columns, that is with eight lighting pushbuttons.

In this case the fixed parts of the display 4, represented in Fig. 3, are substituted by a flange 54 on which the parts which constitute the pushbutton are assemble

The pushbutton activation happens applying a proper pressure on the element 1. This action causes the shifting of the movable part 3 and then the movement on the axis of the switch actuator 25, the pressure on the switch 24 until the activation and then the generation of the signal electrical command. The travel of the display movable part is limited by the mechanical block realized between spring guide 32 and the actuator slide 29, while the spring 33 provides the reinstatement of the initial position of the pushbutton when the action of pressure on the element 1 stops. The lighting is activated by electronic command applied through the connector 10, the flexible 24, electronic parts 30, connector 22, flexible 16, solid state clement 15 like leds or similar components.