JPS58106589A - Display element - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a display element suitable for use as a display device of a display device that performs good display operations both day and night.

Flat thin display elements have been proposed as display devices for devices that display characters, figures, etc. and are limited in space. These display elements include light-emitting display elements such as 1d1 plasma display panel (PDP) and electroluminescent display (ELD'), and light-receiving display elements such as liquid crystal display (LCD) and electrochromic display (ECD).The former emits light by itself. Although it is effective for use in dark surroundings such as at night, the contrast decreases and visibility is poor in situations where sufficient external light can be obtained such as during the day, and it is expensive to prevent this. Luminance of brightness is required. In addition, the latter has higher visibility when there is more external light, and conversely, it may not be possible to display in dark surroundings, so it is suitable for use during the day rather than at night, and when used at night, a dedicated light source is required. Each display element has its advantages and disadvantages, such as the need to provide a display element.

The present invention provides a display element that can be used as a display device of a display device that takes advantage of the space factor and performs good display operation both day and night, based on the characteristics of the various flat thin display elements described above. Specifically, an electroluminescent display section that performs light-emitting display and a liquid crystal display section that performs light-receiving display are integrally stacked between two opposing substrates, and each display section is By driving them individually or simultaneously depending on the surrounding conditions, it is possible to realize a display element having novel display operations and effects not found in conventional flat thin display elements of this type.

Embodiments of the present invention will be described below with reference to the accompanying drawings.

Fig. 1 is a cross-sectional view of the main part of this embodiment, and Fig. 2 is an exploded view showing the same structure. 3 is an IT substrate on the first insulating substrate 2.
A transparent first electrode formed with O to a thickness of 2000 to 3000 A by an electronic vino vapor deposition method, and then subjected to heat treatment;
The film thickness of Y2O3 is 20oO~3o on the first electrode 3.
00A is a transparent first insulating layer formed by electron beam evaporation, and 5 is Z, S:M, on the first insulating layer 4 at a film thickness of 4000 to 6000λ and a substrate temperature of about 200''C. 6 is a normally transparent light emitting layer formed by electron beam evaporation method on the light emitting layer 5, and a transparent second insulating layer formed with the same material and under the same conditions as the first insulating layer 4, 7, ITO is deposited on the second insulating layer 6 to a thickness of 200 mm in an oxidizing atmosphere.
A transparent second electrode within the formation range of the first electrode 3 formed by reactive sputtering at 0 to 3000 A to have a pattern portion 7a corresponding to the display pattern. The electrode 7 constitutes an electroluminescent display section EL; 8 is a transparent second insulating substrate made of a glass plate or the like that faces the insulating substrate 2 with the electroluminescent display section EL sandwiched therebetween; 9;
The second insulating substrate 8 is formed with ITO to a thickness of 2000 to 3000 Å by electron beam evaporation on the surface facing the electroluminescent display portion EL, and is then heat-treated. A transparent 4th electrode 7 that does not face the other part of the electrode 7, 10, a second insulating substrate 8, and an insulating substrate 2.
Second, a frame part for setting intervals made of Epoquin sealant, etc. mixed with spacers to be fixedly adhered from time to time with a small allowable interval;
1.1: P-type TN liquid crystal injected during the above-mentioned small interval, for example, a liquid crystal in which cholesteric liquid crystal in an amount equivalent to 2% of the total amount is mixed into P-type nematic liquid crystal; 12 is a liquid crystal of the second insulating substrate 8; The second electrode 7 to the polarizing plate 12 constitute the liquid crystal display section LC, which is a substantially transparent polarizing plate attached to the display surface.The second electrode 7 is used as a common electrode, and the first electrode The electrode 3 and the second electrode 7, and the second electrode 7 and the third electrode 9 are each connected to a dedicated power source (not shown) via a switch (not shown).

Next, the operation will be explained.

First, the first electrode 3 and the second electrode 7, the second electrode 7
If no voltage is applied to each of the first electrode 3 and the second electrode 9, an electric field will not be generated between the first electrode 3 and the second electrode 7, and the luminescent center in the luminescent layer 5 located between them will not be excited. Therefore, the electroluminescent display section EL maintains its normal transparent state. Since no electric field is generated between the second electrode 7 and the third electrode 9, the liquid crystal 11 (d) located between them (see FIG. 3(a) due to the surface treatment formed on the second insulating substrate 8) As shown in the model, the second electrode 7 and the third electrode 9 are twisted at 90 degrees and arranged in parallel with the electrodes 7 and 9,
Demonstrate the direction of the polarization axis of the polarizing plate 12 in which the pattern portion 7a of the second electrode 7 is formed and the other portion is not formed when viewed from the user M.

Δ(7) Maintain a display that makes people feel uncomfortable.

When displaying a predetermined pattern using this display element when sufficient external light is available, such as during the daytime, the second electrode 7 of the liquid crystal display section LC is activated by operating the switch from the above state.
A voltage is applied only between and the third electrode 9. At this time, since the liquid crystal 11 between the electrodes '7+'' has positive dielectric anisotropy, the director of the cholesteric phase molecules of the liquid crystal 11 tends to be parallel to the direction of the electric field, causing a phase transition to a so-called nematic phase. As shown in the model of FIG. 3(b), the liquid crystal 11 is oriented perpendicularly to the electrodes 7°9.The liquid crystal 11, which is not between the twisted electrodes 7°9, remains parallel to the electrodes 7 and 9 as before. That is, the pattern portion 7a of the second electrode 7
Only the light rays passing through the liquid crystal 11 are not affected by the twisting effect (8) of the liquid crystal 11 and go against the polarization axis of the polarizing plate 12. Since the electroluminescent display section E L maintains a transparent state, only the pattern section 7a of the second electrode 7 has a dark color, and when viewed from the user M, the second electrode 7 of the second insulating substrate 8 has a dark color. A difference in color occurs between a portion corresponding to the pattern portion 7a and a portion not corresponding to the pattern portion 7a, and a predetermined pattern is displayed.

When it is difficult to obtain external light and the surroundings are dark, such as at night, a voltage is applied only between the first electrode 3 and the second electrode 7 of the electroluminescent display section EL.

At this time, the electric field generated in the light-emitting layer 5 excites the electrons in the conduction band and accelerates them, which excites the electrons in the MeA dormant body which is the luminescence center, and when it returns to the ground state, it produces yellow light emission, and this light emission The pattern is formed in a shape corresponding to the pattern portion 7a of the second electrode 7 facing the first electrode 3. Since the liquid crystal display section LC maintains a substantially transparent state, only the portion of the second insulating substrate 8 corresponding to the pattern section 7a of the second electrode 7 when viewed from the user M emits light. Since the dark portion does not emit light, a difference in brightness occurs between the two portions, and a predetermined pattern is displayed.

Therefore, by selectively operating either the smudge light display section EL or the liquid crystal display section LC by operating the switch according to the surrounding situation, a display operation based on a predetermined pattern can be obtained.

FIG. 4 is a sectional view of a main part of another embodiment of the present invention, which is characterized by the structure of the liquid crystal display section LC.

The liquid crystal display section LC of the display element shown in FIGS. 1 to 3 above
The configuration was such that the second electrode 7 was used as one electrode, the third electrode 9 formed on the second insulating substrate 8 was used as the other electrode, and display was performed depending on the alignment state of the liquid crystal 11 between these two electrodes. but,
In this embodiment, ITO is placed on the same plane of the second insulating substrate 8.
The first liquid crystal electrode 9a and the second liquid crystal electrode 9b facing this electrode 9a are formed to have a film thickness of 2000 to 2000 depending on the display shape.
3QOOA, spaced approximately 2-1, by electron beam evaporation, and then heat treated to make it transparent.

A liquid crystal 11 is interposed between the electrodes 9a and 9b, and the liquid crystal 11 is a hemiform nematic liquid crystal mixed with cholesteric phase crystal in an amount corresponding to 2% of the total amount.

Next, the operation of this embodiment will be explained.

First, when no voltage is applied to the first electrode 3 and the second electrode, or the first crystal liquid electrode 9a and the second liquid crystal electrode 9b, the electroluminescent display section EL is the same as that of the embodiment described above. C1
1) Maintain the normal transparent state as well. In addition, the first liquid crystal electrode 9
In order to prevent an electric field from occurring between the liquid crystal electrode 9b and the liquid crystal electrode 9b, the liquid crystal electrode located between them is connected to the IC like the other liquid crystal 11.
As shown in the model in Fig. 5 ia), an irregular focal conic structure is formed in which the twist axes of the cholesteric phase are arranged randomly, so that when viewed from the user M, the first liquid crystal electrode 9a and the second electrode The second part has no difference in color from the part between 9b.
Due to the imaginary determination of the direction of the polarization axis of the insulating group 12, the liquid crystal display section LC maintains a display that gives the impression that nothing is being displayed.

When displaying using the liquid crystal display section LC, a voltage is applied only between the first liquid crystal electrode 9a and the second liquid crystal electrode 9b. Since the liquid crystal 11 has negative dielectric anisotropy, the director of molecules in the cholesteric phase of the liquid crystal 11 between the electric fields 4i9a and 9b tends to be parallel to the direction of the electric field, causing a phase transition to a so-called nematic phase. Figure 5 1
1. ) as shown in the model.

9b, that is, perpendicular to the second insulating substrate 8. Also, the liquid crystal 11 that is not between the electrodes 9a and 9b
remains a focal conic organization. That is, only the light beam passing between the electrodes 9a and 9b is not subjected to the twisting effect by the liquid crystal 11 and is directed against the polarization axis of the polarizing plate 12. and,
Since the electroluminescent display section EL is kept in a transparent state, only the electrodes 9a and 9b are dark in color when viewed from the user M, and a difference in color occurs between the electrodes 9a and 9b and other parts, as shown in FIG. Displays a pattern.

When displaying using the electroluminescent display section EL, (, +Z
) A voltage is applied only between the first electrode 3 and the second electrode 7. At this time, as in the previous embodiment, the electrode 7 of the box 2 emits light in a shape corresponding to the pattern portion 7a. Liquid crystal △ Since the display part LC maintains a substantially transparent state, only the part corresponding to the pattern part 7a of the second electrode 7 of the second insulating substrate 8 as seen from the user M emits light, and the other parts do not. Since the part does not emit light, there is a difference in brightness between the two parts, and the seventh part does not emit light.
A predetermined pattern display as shown in the figure is performed.

Therefore, by selectively operating either the electroluminescent display section EL or the liquid crystal display section LC by operating the switch according to the state of the surrounding situation, a display operation based on a predetermined pattern display can be obtained.

By the way, at night or the like, it is also possible to simultaneously apply a voltage to the electroluminescent display section EL and the liquid crystal display section LC and use the light emitted from the light emitting layer 50 of the electroluminescent display section EL as an illumination light source for the liquid crystal display section LC. .

In any case, the temperature of the liquid crystal 11 can be raised by the heat generation of the light emitting layer 5, so that operation at low temperatures can be compensated for, and there is also the effect that the operating temperature range of the liquid crystal display section LC can be expanded. FIG. 8 is a characteristic diagram showing this function, where the horizontal axis shows the ambient temperature near the display element, and the vertical axis shows the rise time, which is the time for the liquid crystal 11 to transition from a transparent state to a scattering state in response to a switch operation. The voltage applied to the liquid crystal display unit LC is 6 V and the frequency is 100 H when the liquid crystal display unit LC is operated alone and when the electroluminescent display unit EL is used together.
It shows the difference in characteristics in Z. It is clear from this figure that the rise time for each ambient temperature is shorter in the latter case than in the former case (15).
The liquid crystal 11 is heated by the heat generated by the light emitted from the electroluminescent display section EL.
It can be seen that the responsiveness to voltage application can be improved.

The material of the light emitting layer 5 of the electroluminescent display section EL in each of the above embodiments is mainly composed of ZTLS, with M added thereto as an active substance forming a luminescent center, and Tb.

Rare earth elements such as T- and S- may also be used, and light emission unique to each material can be obtained.

The liquid crystal H used in the liquid crystal display section LC has the above-mentioned TN.
A GH type liquid crystal in which a small amount of dichroic dye is added may be used, and in this case, the color can be colored depending on the color characteristics of the added dye.

In this invention, an electroluminescent display section that performs a light emitting display and a liquid crystal display section that performs a light receiving display are integrally stacked between two opposing substrates, and each display section can be displayed independently or simultaneously depending on the surrounding situation. (1) When the surroundings are bright, such as during the day, the display can be displayed using the liquid crystal display, and when the surroundings are dark, such as at night, the display can be displayed using the electroluminescent display, so that only the advantages of the image display can be utilized; Therefore, good display operation can always be obtained.

(2゛1 The electroluminescent display section and the liquid crystal display section are connected at the same time.
The former can also be driven and used as an illumination light source for the latter; in this case, the heat generated by the light-emitting layer of the former can heat the liquid crystal of the latter to raise its temperature, which can compensate for operation at low temperatures. , the operating temperature range of the liquid crystal display section can be expanded.

(3) Since the electroluminescent display section and the liquid crystal display section are integrated in the same space, and the latter's liquid crystal surrounds the former, the liquid crystal that does not contain OH groups functions as a moisture-proof layer for the former. Therefore, the light emitting characteristics of the electroluminescent display section can be stably maintained without forming a moisture-proof layer using other members.

(4) In a display element in which an electroluminescent display element and a liquid crystal display element are separately provided and stacked, at least one transparent substrate is required between the image display element and the liquid crystal display part. There is no need for a predetermined display, so there is no need for two emitted or transmitted light to be partially absorbed within the display element, and there are two brightness colors.

It provides good contrast, high-quality display operation, and can be made thinner.

The present invention has the following effects, and will greatly contribute to the realization and popularization of display elements that have novel display operations and effects that have not been found in conventional flat-panel thin display elements of this type.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of essential parts of an embodiment of the display element of the present invention, FIG. 2 is an exploded view showing the structure of the same embodiment, and FIG. 3 is Oa
), tbl is a molecular orientation model diagram of the liquid crystal of the same embodiment, FIG. 4 is a sectional view of a main part of another embodiment of the display element of the present invention, and FIG. Figures 6 and 7 are diagrams showing the display operation (19) of another example of the same as the above. FIG. 3 is a diagram showing 1-return time characteristics. 2: First insulating substrate 3: First electrode 4; First insulating layer 5: Light emitting layer 6: Second insulating layer 7: Second electrode 8: Second insulating substrate 9: Third Electrode 9a: first liquid crystal electrode
9b: Second liquid crystal electrode 11: Liquid crystal EL:
Electroluminescent display section LC: Liquid crystal display section (20) (a) Fig. 6 5 (b) Fig. 7

Claims (1)

[Claims] Creating a space with a first insulating substrate and a second insulating substrate,
In this space, an electroluminescent display section that emits light when a voltage is applied and a liquid crystal display section that displays by controlling the orientation of liquid crystal molecules by applying a voltage are provided. A display element characterized by having an integral structure that surrounds its surroundings.