JPS6145836B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to display elements used in home appliances and the like.

2. Description of the Related Art Recently, computerization of household electrical appliances has rapidly progressed, and there has been an increasing demand for display elements to display operating modes of appliances. Conventionally, various display elements have been produced, and these will be explained below. Figure 1 shows a push button switch whose button head has the function of emitting light.
is a front view, and FIG. 1b is a side view. In the figure, by pushing the push button 1, the switch body 2 is
is turned on or off, and in conjunction with this operation, the light emitting diode 3 (or incandescent lamp) lights up. The light emitted from the light emitting diode 3 passes through the transparent plastic that constitutes the push button 1 and is emitted from the front surface of the push button 1, making it appear as if the head is emitting light. However, a push button switch with a display device having such a structure has a complicated structure, it is difficult to make the light emitting part large and the depth is deep, and a mounting hole is required to attach it to a panel. However, many of them have drawbacks such as difficulty in mounting them on the same plane. As a solution to some of these shortcomings,
There is a switch with a display device having a capacitance change detection type sensor shown in FIG. In FIG. 2, 5 is a sensor panel that also serves as a display section, and a detection circuit 7 detects a capacitance change between this sensor panel 5 and, for example, a ground plane (a capacitance change due to a person touching the sensor panel). , by turning on and off the switch 8 with the output signal, the incandescent lamp 6 is turned on.
(or a light emitting diode) that blinks. However, even with a switch with a display device having this structure, it is difficult to display a large area, and from a mounting point of view, it is necessary to attach an incandescent lamp or a light emitting diode, and there are disadvantages that the switch is deep.

SUMMARY OF THE INVENTION An object of the present invention is to eliminate the above-mentioned drawbacks of the prior art and to provide a switch with a display device that is thin and easy to implement. In order to achieve this object, the main point of the present invention is to use electrodes of a thin light emitting element placed opposite each other as a sensor for capacitance detection, etc., to create a display element with a built-in switch sensor.
As a result, a thin switch element with a display device can be obtained. In this way, by using the transparent electrode on the first main surface side of the substrate constituting the light emitting element as the sensor electrode, there is no need to provide a sensor electrode for detecting changes in capacitance etc. separately from the display element, and the light emitting part itself A display with a built-in switch sensor can be realized.

In addition, according to this configuration, since the sensor electrode is naturally formed on the back surface of the display panel when forming the light emitting element, it is not necessary to form transparent electrodes on both sides of the panel and to connect from the front surface to the back surface of the panel, thereby simplifying the manufacturing process. Simplified and improved reliability. Furthermore, it is possible to construct a highly reliable switch sensor that is free from malfunctions caused by dirt on the panel, oxidation or damage to the electrodes, and the like.

Next, one embodiment of the present invention will be specifically described using the drawings. First, a transparent glass substrate 10 (40 mm x
40 mm), an In ₂ O ₃ Nesa film (film thickness 2000 Å, sheet resistance 150 Ω/cm ² ) was formed by vapor deposition, and then a Nesa pattern 1 was formed as shown in Figure 3.
The film is removed by etching, leaving only 1. Next, as shown in FIG. 4, a phosphor layer 12 is formed.
The phosphor layer 12 may be screen printed using an electroluminescent phosphor printing paste. At this time, the printing film thickness is preferably about 10 to 40 μm. The reason for this is that when the thickness is less than 10 μm, the dielectric strength of the film is insufficient, and when it is thicker than 40 μm, a high voltage is required to emit light. Next, the fifth
As shown in FIG. 6, the back electrode 13 is formed by aluminum vapor deposition. In addition, Figure 5 is a rear view,
FIG. 6 is a sectional view taken along line XX' in FIG. The electroluminescent display element (hereinafter referred to as an EL display element) manufactured as described above has a NESA pattern 11 on the back surface of the front glass substrate 10, as shown in FIG. By using it as a touch sensor electrode, it can be used as a display element with a built-in switch sensor.

Next, the circuit configuration of this embodiment will be explained with reference to the block diagram of FIG. Figure 7 shows an EL display element
14 , a drive circuit 15, a detection circuit 16, a drive oscillator 17, a switching element 19, and a sensor capacitor 20. Of these, the sensor capacitance 20 will be briefly explained as follows.
In FIG. 6, when a finger touches the front panel 18, if a glass plate or the like is used as the panel material, the finger forms a capacitance of several pF with respect to the Nesa pattern 11 through the glass substrate 10. The sensor capacity is 20.

Next, a method for detecting whether or not there is contact will be described using a specific circuit, taking as an example a case where an induced hum component is used. FIG. 8 shows the circuit. In the figure, 21 is a hum component induced in the human body, which is generally 10 volts or more. When the potential difference of this hum component 21 is injected through the sensor capacitor 20, the drive circuit 29 and the detection circuit 2
Hum noise divided by the ratio of the impedance of the third side and the sensor capacitance 20 is generated at the point A. Although the signal generated at point A is DC biased when the EL element is not driven, it is only a 50Hz or 60Hz hum noise and does not contain other components. However, when touching the touch sensor,
When an EL display element is driven, a drive signal component enters the point A, making it difficult to separate the hum component and the drive signal component. Therefore, in this example,
The EL display element is driven by a drive oscillator 17, whose oscillation frequency is 500Hz, and is detected separately from hum noise at 50Hz or 60Hz. In FIG. 8, 23 indicated by a chain line is a detection circuit;
It is a high input impedance amplifier. The output of the detection circuit 23 is filtered through the low-pass filter 2 shown by the chain line.
4 and pass only the 50Hz or 60Hz component. Next, after removing the DC component, the rectifier circuit 2
5 and output terminal 2 through the waveform shaping circuit 26.
Output to 7. In this case, the potential of the output terminal 27 is
While in contact via the sensor capacitor 20, the potential is high, and when not in contact, the potential is zero. Furthermore, the signal at the output terminal 27 may be processed and input to the drive circuit input terminal 28 according to the display operation mode.

In the embodiments described above, the display element is an EL display element, but if a liquid crystal, an electrochromic element, or the like is used as the display element, the embodiments can be implemented in exactly the same manner.

As described above, according to the present invention, it is possible to obtain a thin display element having a switch sensor in the light emitting part, so that the switches of a product having a large number of switches on the front operation panel can be easily converted into sensors, and the user can easily This makes it possible to have a function that allows you to easily identify the switch that has been touched.

[Brief explanation of the drawing]

Figures 1a and b are front and side views, respectively, of a conventional pushbutton switch with a display device, and Figures 2a and b are front and side views, respectively, of a conventional capacitance change detection type switch with a display device. FIG. 3 is a rear view of a glass substrate with a Nesa pattern used in an embodiment of the present invention, FIG. 4 is a rear view showing the state of the substrate after phosphor printing, and FIG. 6 is a cross-sectional view taken along line X-X' in FIG. 5, FIG. 7 is a block diagram showing the circuit configuration of the embodiment, and FIG. FIG. 2 is a circuit diagram showing a specific example of the detection method of the embodiment. Explanation of symbols, 1...Push button, 2...Switch body, 3...Light emitting diode, 5...Sensor panel, 6...Incandescent lamp, 7...Detection circuit, 8...Switch, 10...Glass substrate , 11... Nesa pattern, 12... Fluorescent layer, 13... Back electrode, 14
...EL display element, 15...Drive circuit, 16
...detection circuit, 17 ... oscillator, 18 ... front panel, 19 ... switching element, 20 ... sensor capacitance, 21 ... hum component, 23 ... detection circuit,
24...Low pass filter, 25...Rectifier circuit,
26... Waveform shaping circuit, 27... Output end, 28...
...drive circuit input terminal, 29 ...drive circuit.

Claims (1)

[Claims] 1. A thin display element formed by sequentially laminating a transparent electrode, a display layer, and a transparent or opaque electrode on a partially or fully transparent substrate, and the display element is mounted on the substrate. The electrode of at least one display element provided on the first main surface of the substrate is used as a sensor electrode, and the hum component applied by the capacitance generated between this and the second main surface of the substrate is detected. 1. A display element with a built-in switch sensor, comprising a detection circuit for controlling a drive circuit for a switch element or a power source for driving the display element based on an output of the detection circuit.