JPH01118115A - Electrochromic display element - Google Patents

Abstract

PURPOSE:To decrease the driving current at the time of coloring and decoloring and to enable high-speed address control by alternately forming the boundary faces of 1st regions consisting of electrochromic materials and 2nd regions consisting of electron blocking type materials in multiple stages between electrodes. CONSTITUTION:This display element has the layer dispersed with many microparticles 7, in which the electrochromic materials 3' consisting of a transition metal oxide and the electron-donative materials 4' are paired and are incorporated, within the electron blocking type materials 5' consisting of an insulator between a transparent electrode 2 and a counter electrode 6. Since the directions of the boundary faces of both the materials 3', 4' in the respective microparticles 7 are randomly formed, the components parallel with the directions of both the electrodes exist at least at 50% in the boundary face directions thereof. Polarization is, therefore, generated in the electrochromic regions 3' of the microparticles 7 and the electron-donative regions 4' when a voltage is impressed to the electrodes. The need for ion conduction is thereby eliminated and the driving current is decreased in the coloring and decoloring operations. The high-speed display is thus enabled.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electrochromic display element, and more particularly to an electrochromic display element that can perform high-speed display with a small current by using charges due to polarization without ion conduction during coloring/decoloring operation.

In conventional electrochromic elements, the display electrode and the
For example, an electrochromic j- of M-pole metal oxide and an ion conductive layer are provided between the electrodes to cause ion conduction, and electrons corresponding to this charge are injected and released into the electrochromic ~ to display color/decolorization. It is done. This group had a drawback in that the driving current was excessive because a charge of about 5 mCβ was required for coloring. This problem becomes particularly serious during high-speed address control. Furthermore, since ion conduction is essential during the coloring/decoloring operation as described above, there is a drawback that the addressing speed is limited by this.

An object of the present invention is to provide an electrochromic display element that requires a small drive current during coloring/decoloring and can perform high-speed address control.

In order to achieve the above object, the electrochromic display element of the present invention includes an electrochromic substance and an electron supplying substance as a pair between a display electrode and a counter electrode.
and a second region made of an electron blocking substance,
It is characterized in that the first region is dispersed as a large number of minute regions in the second region.

Examples will be described in detail below.

Figures (α) and (6) of Section 1 are explanatory diagrams showing the configuration of an embodiment of the present invention.

In the figure, between the transparent electrode 2 and the counter electrode 6, Won
A large number of microparticles 7 containing a pair of an electrochromic material 3' made of a transition metal oxide such as a transition metal oxide and an electron supplying substance 4' such as InzOs are combined with an electron supplying material made of an insulator such as silicon oxide. It has a layer dispersed within the block material 5'.

Since the directions of the interfaces between the two substances 5' and 4' in each microparticle 7 are formed randomly, there exists a component of at least 5 oqlI of these interfaces that is parallel to the direction of the picture electrode.

Therefore, when a voltage of, for example, DClooV is applied to the electrode, the electrochromic region 3' of the microparticle 7, ! :.

Polarization occurs in the electron supply region 4' as shown in FIG. 6 (6) K.

In this case, some parts are colored and some parts are not colored depending on the positional relationship between the electrochromic region 3' and the electron supply layer A. That is, when the electroclockwise clock region 3' is closer to the electrode than the electron supply region 4', color is produced, and in the opposite case, no color is produced. However, if a large number of such colored regions exist, the device as a whole becomes colored. The size of each particle is preferably about 5A to about 100A.

As a method of manufacturing the device, a method of simultaneously producing multiple films by vapor deposition, sputtering, ion grating, etc. is used. ``Furthermore, the following two methods are used to form particles 7 in which the electron supplying substance 3' and the electron supplying substance 4' form a pair, such as the same layers (α) and (b).

Method #11 involves depositing an electron-blocking material and then simultaneously depositing an electrochromic material and an electron-supplying material. And repeat this many times.

In the second method, after depositing an electron blocking material, depositing an electrochromic material and then depositing an electron supplying material. Then repeat this 9 times.

Above 1st. Among the second methods, the second method in particular can impart directionality to the positional relationship between the electrochromic substance and the electron supplying substance, and can effectively perform coloring.

When implementing these methods, it is desirable that the thickness of the electrochromic material or electron supply material be L1≦50, and the thickness of the electron blocking material be L2≧2L.

In this case, the conditions for forming the electrochromic substance/electron supply substance into particles include the degree of vacuum at the time of preparation, substrate temperature, and deposition rate.

For example, when creating an electrochromic material or an electron supplying material, if deposited at a low vacuum of 10 Torr or less, it tends to become multi-particulate, whereas electron blocking materials are deposited at a high vacuum of 10 Torr or more. It becomes fine particles and can be layered.

In addition, the substrate temperature was set to 100°C when creating the electronic block material.
When preparing the electrochromic substance/electron supply substance, the temperature is set at 100° C. or higher, so that it becomes easily formed into a multi-particulate form.

Furthermore, the faster the depositing speed, the easier the formation of particulate Kfk in the initial state.

As the electron blocking substance in the above embodiments, for example, an ordinary insulator such as silicon nitride, silicon oxide, tantalum oxide, or alumina, or a high resistance semiconductor of 10"01 or more is used. As the electron supplying substance, for example, Metals or I 320s eSnow, transition metal oxides, etc. are used.

In this case, a transition metal oxide such as WO3 is used as the electrochromic material, but it is desirable that the transition metal oxides in both layers have different oxidation numbers. That is, when one uses a metal oxide with a high oxidation number, the other uses a metal oxide with a low oxidation number.

Here, metal oxides with low oxidation numbers are oxidized (electron emission)
A metal oxide with a high oxidation number is one that becomes a lower order oxide through reduction (electron injection).

In addition, substances that color by electron extraction, such as V2
O3, Won, CshunOs NiOs S30. P
bO* OsO* Ti(L Gazes * cal
o, TbzOs + SiOs Ta0r FgOe
MOO2.

CrOt MiOr UOz e Co Or Crz
When Os or the like is used as the electron supply layer, it is extremely effective in enhancing or changing the coloring in conjunction with the electrochromic layer.

As described above, according to the present invention, the interface between the first region made of an electrochromic material and the second region made of an electron blocking material is alternately formed in multiple stages between the electrodes. That is, the first region and the second region in which the electrochromic material and the electron supply material are paired,
This can be achieved by dispersing the first region as microparticles in the second region.

As a result, since ion conduction is not involved in the coloring/decoloring operation, a drive current is small and a high-speed display function can be obtained.

[Brief explanation of the drawing]

FIGS. 1(α) and 1(b) are explanatory diagrams showing the structure of another embodiment of the present invention, in which 1 is a glass substrate, 2 is a transparent electrode, 3' is an electrochromic material, and 4' is an electron The supply material, 5' is an electron blocking material, and 6 and 117 are fine particles.

Claims (3)

[Claims] (1) A first region containing a pair of an electrochromic substance and an electron supplying substance between a display electrode and a counter electrode, and a second region consisting of an electron blocking substance;
An electrochromic display element comprising a plurality of micro-regions dispersed in a second region. (2) The electrochromic display element according to claim 1, wherein the electron supplying substance is a substance that develops color by abstracting electrons. (3) The electrochromic material according to claim 1, wherein one of the electrochromic substance and the electron supply substance is a metal oxide with a low oxidation number and the other is a metal oxide with a high oxidation number. Chromic display element.