JPS5821234B2 - Electronic clock display device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement of a lighting device in an electronic timepiece equipped with a light-receiving electro-optical display device.

Conventionally, electronic wristwatches equipped with light-receiving electro-optic displays such as liquid crystal displays have been inferior to external displays or luminescent displays such as light emitting diodes in terms of display clarity in dark places.

In order to improve this point, the current amount is also used as a general method.
Lighting is done with incandescent bulbs.

However, this method required a light-guiding space below the liquid crystal for the passage of light from the incandescent bulb, which hindered the creation of thinner wristwatches.

Furthermore, since the reflective surface in daylight is separated from the liquid crystal surface, there is a drawback that the displayed image appears double when viewed from the waist direction.

Regarding the lighting effect, since the light source is a point light source or a line light source, a brightness gradient occurs on the liquid crystal display surface, and a sufficient lighting effect cannot be obtained.

On the other hand, a method has been considered in which a reflective surface coated with a luminescent or self-luminous substance is placed behind the liquid crystal display element.
This method did not provide enough light, and in some cases there was a problem with radiation damage, so it was not a sufficient lighting method.

An object of the present invention is to eliminate the above-mentioned drawbacks of the prior art and provide a method for increasing sufficient illumination effects using a thin surface light source. The electro-optical display device is characterized in that an electroluminescent cell for illumination is integrated into the electro-optical display device.

Hereinafter, specific examples of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a cross-sectional view of a liquid crystal cell (hereinafter referred to as LC cell) that is a light-receiving display device used in the present invention and an electroluminescent cell (hereinafter referred to as EL cell) that is a lighting device. A cell 10 is an EL cell placed on the back side of the LC cell 1.

The LC cell 1 has between an upper glass 2 and a lower glass 3,
A twisted nematic liquid crystal 4 is sealed by a sealing member 5, and an upper polarizing plate 6 and a lower polarizing plate 7 are provided on the upper and lower surfaces of the upper glass 2 and lower glass 3, respectively, with their polarization axes perpendicular to each other. Furthermore, the upper glass 2
A transparent upper electrode 8 and a lower electrode 9 are formed on the inner surface of the lower glass 3.

It is well known that in such an LC cell 1, when a voltage is applied between the upper electrode 8 and the lower electrode 9, the overlapping part of both electrodes becomes opaque. The display pattern is divided into two parts to obtain a display pattern suitable for the display purpose.

On the other hand, the EL nacelle 0 includes a transparent electrode 11 formed by a method described later on a transparent or semi-transparent substrate 12 such as opal glass, an insulating film 13 such as barium titanate, and an electroluminescent material. 14 (hereinafter referred to as EL material) is applied to a metal plate 15 in a layered manner, and the periphery thereof is sealed with a moisture-proof seal 16.

The transparent electrode 11 is made by etching a metal thin film obtained by vapor deposition into a mesh shape by etching '77 [II],
These include those made by vapor-depositing indium oxide and those made by hydrolyzing and sintering tin oxide.

Further, as the EL material 14, zinc sulfide mixed with a small amount of copper is usually used.

The EL nacelle 0 having the above structure has a 100 mm
By applying an AC voltage of ~200 μm, the EL material 14 emits light and emits light through the transparent electrode 11 and the substrate 12.

FIG. 2 shows the LC cell 1 and EL nacelle 0 shown in FIG.
FIG. 3 is a cross-sectional view showing the display state in which A shows the state under daylight, and the mouth shows the state in a dark place.

That is, in Figure A, the light ray 11 that enters the non-displayed part of the LC cell 1 is transmitted through the surface layer of the EL nacelle 0 and the EL substance 1.
The reflected light rays 11 are reflected and scattered by the light emitting layer etc.
', which reaches the observer's eyes, but since the light ray 12 that enters the display area (shown with diagonal lines) is absorbed in the LC cell 1, the light ray 12' that is reflected back to the EL nacelle 0 is weak. As a result, a pattern based on the difference in brightness is displayed on the LC cell 1.

On the other hand, loss indicates a state in which the EL nacelle 0 is emitted in a dark place, and the light rays emitted from the EL nacelle 0 are incident on the bottom surface of the LC cell 1, but the light rays 13 that have entered the non-display area are The light ray 14 passes through the LC cell 1 and reaches the observer's eye, but the light ray 14 enters the non-displayed area (shown with diagonal lines).
Since the light is absorbed and attenuated in the LC cell 1, a pattern is displayed on the LC cell 1 even when there is a difference in brightness.

FIG. 3 is a cross-sectional view of a composite cell in which the LC cell 1 and the EL nacelle are integrated, and the composite cell 20 includes the upper glass 2, the lower glass 3, the twisted nematic liquid crystal 4,
An LC cell 1 constituted by a sealing member 5, an upper polarizing plate 6, and a lower polarizing plate 7, and an EL integrally constituted below the LC cell 1.
It is composed of cells 21.

The structure of the EL nacelle 1 is that 22 is a glass substrate with a diffused reflection surface formed on the upper surface, and the lower surface of the glass substrate 22 has
A transparent electrode 23 constituting an upper electrode is formed.

24 is an insulating substrate made of ceramic, glass, etc., and a lower electrode 25 is provided on the upper surface of the insulating substrate 24.
However, on the lower surface, a shield electrode 26 is formed by a technique such as printing or vapor deposition, and furthermore, on the upper surface of the lower electrode 25, the insulating film 13 of barium titanate or the like and EL are formed.
The material 14 is applied in layers.

Further, the lower electrode 25 passes through a through hole 24 a provided in the insulating substrate 24 to form a connecting electrode 25 a on the lower surface of the substrate 24 , and the upper electrode 23 connects to the shield electrode 26 through a conductive connecting member 27 . electrically connected to.

After the glass substrate 22 and the insulating substrate 24 are brought into close contact with each other, they are laminated from the bottom side of the LC cell 1, and the entire periphery is sealed with a moisture-proof seal 28.

In the composite cell 20 having the above configuration, a signal voltage is applied to the connection electrode 8a formed at the end of the upper glass 2 to drive the display of the LC cell 1, and a lower electrode formed on the lower surface of the insulating substrate 24 is operated. 25 connection electrode 25a and shield electrode 2
By applying a high AC voltage between the electrodes 6 and 6, an AC electric field is generated between the upper electrode 23 and the lower electrode 25, and the EL cell 21 is driven.

FIG. 4 is a cross-sectional view showing the arrangement of the electronic timepiece according to the present invention, including a case body 30, a windshield 31, and a back cover 32.
The composite cell 20 is arranged in correspondence with the windshield 31 inside a watch case configured by the above, and a battery 33 for power supply and a watch unit 34 driven by the battery 33 are placed below the composite cell 20. , EL cell drive circuit 35 are arranged, respectively.

Note that the shield electrode 26 provided at the lower part of the composite cell 20 is exposed to the clock unit 34 due to the high voltage AC electric field generated inside the EL cells 21 constituting the composite cell 20.
is protected from causing logical corruption.

FIG. 5 is a wiring diagram of the EL cell drive circuit 35 shown in FIG. 4, in which the battery 33, the clock unit 34, the EL cell 21,
The upper electrode 23, the lower electrode 25, and the shield electrode 26 are as described above, and further, 36 has three windings 1.
37 is a driving transistor, 38 is a bias resistor, 39 is a coupling capacitor, and 40 is a switch for lighting the EL cell controlled by an external operating member. be.

The EL cell drive circuit 35 constituted by the transistor 37, resistor 38, capacitor 39, and transformer 36 constitutes a collector-tuned anticoupling oscillation circuit using the EL cell 21 as a collector-tuned capacitor.

Here, each winding of the transformer 36. L2. L, are all wound in the same direction, and their winding start terminals are as indicated by black dots.

Also, winding. is the other winding L1. By making the number of turns sufficiently thick (10:1000) compared to L, a high AC voltage is generated in the collector tuning circuit, and the EL cell 21 is excited to emit light.

Each electrode of the EL cell 21 is connected to the upper electrode 23 and the shield electrode 26 as shown in FIG.
By connecting the lower electrode 25 to the ground terminal of the lower electrode and wrapping the lower electrode 25 between the two electrodes, the high-voltage AC electric field is shielded from leaking to the outside.

6 and 7 show other embodiments of the composite cell in the present invention, and the composite cell 50 shown in FIG.
By guiding the lower electrode 25 and the shield electrode 26 to the ends of the upper glass 2 of the LC cell 1 using conductive connecting members 51 and 52, respectively, to form a connecting electrode, the LC cell and the EL nacelle are connected. External connections are made from the same surface.

Furthermore, the composite cell 60 shown in FIG.
By forming the cell, the glass substrate 22 is omitted and the cell is made thinner.

Furthermore, it is also possible to omit the conductive connection member 2T and extend a portion of the lower polarizing plate 7 on which the conductive film is formed to connect it to the shield electrode 26.

As mentioned above, as a lighting device for LCD wristwatches,
By using an EL nacelle, the entire surface of the liquid crystal display device can be illuminated with uniform brightness, and the spectrum of emitted light can be changed by selecting the EL material, making it possible to produce colorful displays. It becomes possible.

In addition, when used as an EL nacelle reflective surface, a good reflective surface can be obtained due to the bright yellow-green color of the EL substance containing zinc sulfide as a main component and the white color of the barium titanate layer underneath.

Furthermore, by integrating the LC cell and the EL nacelle to form a composite cell, it is possible to make the entire watch thinner, and the ease of assembly is significantly improved.

[Brief explanation of drawings]

1 and 2 are cross-sectional views of a liquid crystal cell and an electroluminescent cell, FIG. 3, FIG. 6, and FIG. 7 are cross-sectional views of a composite cell according to the present invention. FIG. 5, which is a sectional view of the electronic timepiece according to the invention, is a wiring diagram of the EL cell drive circuit. 1... Liquid crystal cell, 10... Electroluminescence cell, 20, 50, 60... Composite cell.

Claims (1)

[Claims] 1. A light-receiving type electro-optical display device comprising a dog-shaped upper glass and a small-shaped lower glass, and having a connection electrode for an input signal at a protruding end of the upper glass, and the display device In an electronic watch that uses an electroluminescent cell for illumination, the electroluminescent cell is integrated with the lower surface of the lower glass of the display device to form a composite cell, and the driving electrode of the electroluminescent cell is connected to a conductive connecting member. An electronic time display device, characterized in that the display device and the external connection electrodes of the electroluminescence cells are provided on the same plane by leading to the upper glass end of the display device through the interface.