JP4459638B2 - Pushbutton switch with liquid crystal display - Google Patents

Description

  The present invention relates to a pushbutton switch with a liquid crystal display that enables multicolor display using a liquid crystal panel that displays information such as characters and pictures.

  Conventionally, for example, when a push button switch is attached to a vending machine, the function of the push button switch is generally indicated by displaying a charge, a product name, etc. around the push button switch or on the upper surface of the button. there were. However, in the case where the display must be changed due to a change in price or product name, there is a problem that the pushbutton switch itself must be replaced.

Therefore, an LED display device or a liquid crystal display device incorporated into a pushbutton switch has been developed so that various displays can be performed.
Japanese Utility Model Publication No. 7-22012

Conventionally, however, the liquid crystal display screen is black and white as is usually seen on a calculator, and if you want to perform color display, the entire surface of the liquid crystal is simply switched to two colors, red and yellow, using a backlight. It was.
Further, in a general STN (super twist nematic) type liquid crystal, there is a problem in visibility depending on the direction due to viewing angle, contrast, and the like.

Furthermore, with the increase in the number of functions in the market, there is a demand for push button switches capable of multi-color display.
In view of the above circumstances, an object of the present invention is to provide an inexpensive pushbutton switch with a liquid crystal display that has a wide viewing angle, high-speed response, high contrast, and extremely good visibility.

In order to achieve the above object, the present invention provides
[1] A liquid crystal display device including a liquid crystal plate for displaying information such as characters and pictures on the upper surface of the operation button and a printed circuit board on which an IC chip constituting a drive circuit of the liquid crystal plate is mounted is disposed in the operation button. In this pushbutton switch comprising a switch body provided with a contact mechanism that opens and closes an electric circuit by moving the operation button up and down, the drive circuit includes a circuit that alternately applies voltages of both polarities, and a liquid crystal that is turned off. A circuit for generating a reset signal for applying an applied voltage of 0 V when the display is turned off is provided in the IC chip, the liquid crystal plate is an antiferroelectric liquid crystal panel, and a backlight light source composed of a plurality of colors is sequentially provided below the liquid crystal panel. It is possible to turn on at high speed and synchronize with the lighting to display liquid crystal screens with different display contents for each backlight color, enabling multi-color display.

The pushbutton switch with a liquid crystal display of the present invention uses a liquid crystal plate as an antiferroelectric liquid crystal panel, and a backlight light source composed of a plurality of colors is turned on in order and at high speed, and each backlight color is synchronized with the lighting. Multi-color display is possible by displaying liquid crystal screens with different display contents.
In addition, the drive circuit is composed of a circuit that alternately applies voltages of both polarities and a reset signal circuit that sets the applied voltage to 0 V when the power is turned off and the liquid crystal display is turned off. Therefore, it is possible to provide an inexpensive pushbutton switch with a liquid crystal display which has high contrast and extremely good visibility and prevents the liquid crystal display surface from being burned.

  The present invention provides an anti-ferroelectric liquid crystal panel as a liquid crystal panel in order to obtain an inexpensive pushbutton switch with a liquid crystal display, which has a wide viewing angle, high speed response, high contrast and extremely good visibility and prevents the liquid crystal display surface from being burned. The backlight light source composed of a plurality of colors is turned on in order and at a high speed, and a liquid crystal screen with different display contents for each color of the backlight is displayed in synchronization with the lighting, thereby enabling multi-color display. The drive circuit is provided with a circuit for alternately applying bipolar voltages and a circuit for generating a reset signal for setting the applied voltage to 0 V when the power is turned off to turn off the liquid crystal display.

Hereinafter, embodiments of the present invention will be described in detail.
FIG. 1 is a sectional view of a main part of a pushbutton switch with a liquid crystal display showing an embodiment of the present invention, and FIG. 2 is an exploded perspective view of the pushbutton switch with a liquid crystal display.
In these drawings, reference numeral 1 denotes a switch body, and an operating shaft 2 is mounted at the center of the switch body 1. A recess 3 is formed on the left side of the switch body 1, and a connector 4 with a switch terminal 5 is provided below the recess 3. The connector 4 is connected to a circuit pattern 11A at one end of a flexible printed wiring board 10 described later.

  The flexible printed wiring board 10 is formed with through holes 12 through which the operating shaft 2 passes, and circuit patterns 11A and 11B and mounting holes 13 to which the printed circuit board 15 and the holder 20 are fixed are provided at both ends thereof. Plungers 6 are positioned at the upper end of the operating shaft 2 and protrusions 7 are formed at both ends thereof, to which the flexible printed wiring board 10 is attached. The circuit pattern 11 </ b> B at one end of the flexible printed wiring board 10 is connected and fixed to the back surface of the printed board 15. An IC chip 16 to be described later is mounted on the printed board 15. A holder 20 is provided on the printed circuit board 15, and a protrusion (not shown) on the lower surface of the holder 20 passes through the through hole 14 of the printed circuit board 15 and the attachment hole 13 for fixing the flexible printed wiring board 10. 20, the printed circuit board 15, and the flexible printed wiring board 10 are fixed. Further, two pairs of multicolor (red, green, blue, etc.) light emitting diodes 21, 22, 23 and 24, 25, 26 are arranged on the holder 20, and the light emitting diodes 21 to 26 are arranged on the circuit board 15. Connected to the pattern. The light emitting diode may have a shape in which a plurality of colors are integrated.

  Further, on the side of the holder 20 where the light emitting diodes 21 to 26 are not disposed, projecting portions 27 and 28 are formed facing both sides, and long holes 29A and 29B (not shown) are formed inside thereof. The Zebra connectors 31 and 32 are mounted on the circuit pattern on the upper surface of the printed board 15 through the long holes 29A and 29B, and an antiferroelectric liquid crystal panel 33 is disposed above the zebra connectors 31 and 32. . Further, inside the zebra connectors 31 and 32, the diffusing member 30 is disposed in a space between the light emitting diodes 21 to 26 disposed to face the holder 20. An operation button 34 is provided so as to cover the above-described assembly, and a display portion 35 made of a translucent member is formed at the center of the operation button 34.

The plunger 6 is also elastically fitted in the space of the operation button 34, and the operation button 34 accommodates the antiferroelectric liquid crystal panel 33 to the plunger 6 as described above.
A switch mechanism portion is provided in the switch body 1 and projects an operating shaft 2 that drives the switch mechanism portion.
The shaft 8 projecting downward from the plunger 6 and the operating shaft 2 are connected so as to be able to transmit an operating force. Furthermore, the flexible printed wiring board 10 is bent at the end of the plunger 6, the operating shaft 2 passes through the through hole 12 of the flexible printed wiring board 10, and the circuit pattern 11 </ b> A at one end of the flexible printed wiring board 10 is connected to the switch terminal 5. It is connected to the attached connector 4.

  From the above configuration, power is supplied from the switch terminal 5 of the connector 4 with the switch terminal 5 to the printed circuit board 15 via the flexible printed wiring board 10, and further, the light emitting diodes 21, 22, Electric power is supplied to 23, 24, 25, 26 and the antiferroelectric liquid crystal panel 33. The drive control of the light emitting diodes 21, 22, 23, 24, 25, 26 and the antiferroelectric liquid crystal panel 33 is performed by the IC chip 16, and various characters and pictures are displayed and various color tones are changed. Can do.

FIG. 3 is a block diagram showing a circuit configuration of a pushbutton switch with a liquid crystal display according to an embodiment of the present invention.
As shown in this figure, in the circuit 40 of the pushbutton switch with a liquid crystal display, in order to drive the antiferroelectric liquid crystal panel 33 disposed on the upper surface of the operation button, the timing control circuit 41, the signal side voltage waveform generation An IC chip including a circuit 43, a scanning side voltage waveform generation circuit 45, a backlight lighting circuit and backlight 46, a signal side reset signal generation circuit 42, and a scanning side reset signal generation circuit 44, which will be described later, is provided. Reference numeral 47 is a switch mechanism, 48 and 49 are switch terminals, 51 is a display data generation source, and 52 is an external power source.

  FIG. 4 shows the applied voltage of the antiferroelectric liquid crystal according to the embodiment of the present invention and the change of the transmittance with respect to the applied voltage. It has a sequential response in which the liquid crystal molecules are reliably inverted by writing, can operate at high speed, and is extremely inexpensive compared to TFT (thin film transistor) type liquid crystal. For high-speed operation, since it is necessary to display one screen at a speed of 60 Hz or higher, 60 Hz × 3 = 180 Hz per screen. In other words, the value necessary for the liquid crystal operation speed is required to be 5.6 ms or less per screen.

  In FIG. 4, the horizontal axis represents the applied voltage, and the vertical axis represents the relative light transmittance. Since the liquid crystal cell is in a dark state at an applied voltage of 0 V, when the applied voltage is increased in the positive direction, the arrangement of liquid crystal molecules starts to change, and changes to a bright state as the applied voltage increases. That is, the state changes from dark to bright as the applied voltage changes. Further, when the applied voltage is changed in the negative direction, the state changes from dark to bright as in the positive direction. In the present invention, both positive and negative voltages are applied alternately.

  In the present invention, such an anti-ferroelectric liquid crystal panel 33 is arranged on the back surface of the display unit 35 at the center of the operation button 34, and light emitting diodes 21, 22, 23, which are independent backlight sources of a plurality of colors, are provided. 24, 25, and 26 are turned on in order and at high speed, and in synchronization therewith, the display unit (liquid crystal screen) also displays screens with different display contents for each backlight color, and multi-color display is obtained by the afterimage effect of the eyes. Is.

  If the liquid crystal display is turned off by turning off the power with the antiferroelectric liquid crystal panel 33 displaying characters, pictures, etc., it will be extinguished in the holding state where the applied voltage is applied, and it will be used for a long time. Otherwise, there is a problem that the liquid crystal panel is burned and the display becomes unclear. However, according to the present invention, when the power is turned off and the liquid crystal display is turned off, the reset signal for setting the applied voltage to 0 V is used. The IC chip 16 is provided with a signal-side reset signal generating circuit 42 and a scanning-side reset signal generating circuit 44. That is, when the liquid crystal display is turned off by turning off the power supply, the liquid crystal cell can be brought into a dark state at an applied voltage of 0 V, so that the liquid crystal display is not turned off in a holding state where the applied voltage is applied, Even if the liquid crystal panel is used for a long time in the OFF state, it is possible to prevent the liquid crystal panel from being seized.

The present invention uses an antiferroelectric liquid crystal panel capable of simultaneously realizing a wide viewing angle, high-speed response, and high contrast from the above-described configuration, and a plurality of colors of backlight light sources are sequentially and rapidly provided below the liquid crystal panel. It is characterized in that a multi-color display is made possible by lighting up and displaying liquid crystal screens with different display contents for each color of the backlight in synchronization with the lighting.
In addition, a circuit that alternately applies bipolar voltages and a circuit that generates a reset signal that sets the applied voltage to 0 V when the power is turned off and the liquid crystal display is turned off are incorporated into the IC chip, thereby maintaining the applied voltage. The liquid crystal panel can be prevented from being burned in, and an inexpensive pushbutton switch with a liquid crystal display having a wide viewing angle, a high-speed response, and a high contrast can be obtained.

  In addition, this invention is not limited to the said Example, Based on the meaning of this invention, a various deformation | transformation is possible and these are not excluded from the scope of the present invention.

The pushbutton switch with a liquid crystal display of the present invention is suitable for a pushbutton switch with a liquid crystal display that enables multi-color display that can prevent a liquid crystal panel that displays information such as characters and pictures.
In addition, a switch and a display can be used in combination, and can be used freely for various purposes.

It is principal part sectional drawing of the pushbutton switch with a liquid crystal display which shows the Example of this invention. It is a disassembled perspective view of the pushbutton switch with a liquid crystal display which shows the Example of this invention. It is a block diagram which shows the circuit structure of the pushbutton switch with a liquid crystal display which shows the Example of this invention. It is a figure which shows the applied voltage of the antiferroelectric liquid crystal which shows the Example of this invention, and the change of the light transmittance with respect to it.

DESCRIPTION OF SYMBOLS 1 Switch main body 2 Actuation axis | shaft 3 Recess 4 Connector with switch terminal 5 Switch terminal 6 Plunger 7 Protrusion 8 Axis 10 Flexible printed wiring board 11A, 11B Circuit pattern 12, 14 Through-hole 13 Mounting hole 15 Printed circuit board 16 IC chip 20 Holder 21 , 22, 23, 24, 25, 26 Light emitting diode 27, 28 Protruding part 29A, 29B Long hole 30 Diffusion member 31, 32 Zebra connector 33 Antiferroelectric liquid crystal panel 34 Operation button 35 Display part 40 Pushbutton switch with liquid crystal display Circuit 41 timing control circuit 42 signal side reset signal generation circuit 43 signal side voltage waveform generation circuit 44 scanning side reset signal generation circuit 45 scanning side voltage waveform generation circuit 46 backlight lighting circuit and backlight 47 switch mechanism 48, 49 switch Terminal 51 display data generation source 52 external power supply

Claims (1)

A liquid crystal display device comprising a liquid crystal plate for displaying information such as characters and pictures on the upper surface of the operation button and a printed circuit board on which an IC chip constituting a driving circuit of the liquid crystal plate is mounted is disposed in the operation button. In a pushbutton switch consisting of a switch body provided with a contact mechanism that opens and closes an electric circuit by moving the button up and down,
The driving circuit is provided with a circuit for alternately applying bipolar voltages and a circuit for generating a reset signal for setting the applied voltage to 0 V when the liquid crystal display is turned off by turning off the power supply. The backlight light source consisting of multiple colors is turned on in order and at high speed, and the liquid crystal screens with different display contents for each backlight color are displayed in synchronization with the lighting. Push button switch with liquid crystal display that enables multi-color display.

Images