JPS63121296A - Thin film light emitting device - 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 [Industrial Application Field] The present invention relates to a thin film light emitting device, and particularly to a light emitting device suitable for use in a color display panel.

[Prior Art] Thin film light emitting devices that utilize electroluminescence, that is, electroluminescent (El) devices, have a wider operating range and faster response speed than other flat display devices such as liquid crystal display devices and plasma display devices. It has characteristics such as being fast and compact, and it is desired to realize a color display panel using it.

Possible methods for achieving this include stacking luminescent layers that emit light of different colors, or dividing the negative-side luminescent layer into patterns that emit different luminescent colors.

[Problems to be Solved by the Invention] However, according to the first method, since an electrode and, if necessary, an insulating layer are laminated between each light emitting layer, the structure becomes complicated and reliability is lacking. is. Further, according to the second method, it is necessary to dope different impurities into the light emitting layer according to the pattern, which makes patterning complicated and poor in productivity, and the display pattern becomes fixed. There is.

SUMMARY OF THE INVENTION In view of these problems, an object of the present invention is to provide a thin film display element that has a simple structure, excellent productivity, and a high degree of freedom in display patterns.

[Means for Solving the Problems] The structure of the present invention will be explained with reference to FIG. 1. Reference numeral 1 denotes a light-emitting layer that emits white light when an electric field is applied. Striped parallel electrodes 2.3 are formed above and below with the light emitting layer 1 in between.

These upper and lower parallel electrodes 2 .
It's Toshide. Color filter layers 4r, 4g, and 4b that selectively transmit a predetermined color are alternately formed on these adjacent light-emitting pixels E.

[Operation] When the parallel electrodes 2.3 are selectively energized, the light-emitting pixels E located at the intersections of the selected parallel electrodes 2.3 emit white light. The white light is converted into a predetermined color by the color filter layers 4r, 4g, and 4b provided on each light-emitting pixel E, and is sent out. By appropriately selecting the energization to the parallel electrodes 2.3 and combining the predetermined colors, any desired coloring and display pattern can be obtained.

[Effects] According to the above structure, there is no need to stack the luminescent layer or pattern and dope the luminescent layer with different impurities, so the structure is simple, the productivity is good, and the display pattern is highly flexible. .

[Example] In FIG. 1, a plurality of striped parallel electrodes 2 having a constant width are formed on the lower surface of a glass substrate 5.

The parallel electrode 2 is a transparent electrode made of ■n203. An insulating layer 61 made of Ta205 or the like is formed on the lower surface of the transparent electrode 2, and a light emitting layer 1 is further formed below the insulating layer 61. The light emitting layer 1 is formed by electron beam evaporation of sintered pellets made of ZnS as a base material and mixed with PrF3 as an impurity.

l! on the lower surface of the light emitter layer 1! An insulating layer 62 having the same composition as the insulating layer 61 is formed through a buffer layer 63 made of 2 O3 or the like, and a plurality of striped parallel electrodes 3 of a constant width made of 2 O3 or the like are formed roughly on the lower surface thereof. This is the back electrode. The transparent electrode 2 and the back electrode 3 are formed in directions perpendicular to each other, and the portion of the light emitting layer 1 located at the intersection of these serves as a light emitting pixel E. As shown in the figure, the light emitting pixels E have a matrix shape.

Color filter layers 4r, 4Cl, and 4b are provided on the glass substrate 5 to correspond to each light emitting pixel E. The color filter layers 4r, 4C1, and 4b are obtained by patterning an organic thin film such as gelatin or casein into a pixel shape by photolithography, and then dyeing the film. Color filter layer 4
r, 4g, 4b are red (wavelength 640-780nm)
), green (wavelength 498-530nm), blue (wavelength 467-530nm)
483 nm), and these are arranged alternately on the glass substrate surface.

Below the back electrode 3, silicone oil 7 is sealed with a sealing glass 8 to prevent moisture from entering the light emitting element.

When an AC voltage is applied between the transparent electrode 2 and the back electrode 3 from the current supply device in the enclosure, the light emitting pixel E at the intersection of these
emits light. That is, the insulating layer 61.6 is
Electrons in the phosphor layer 1 close to PrF3 are accelerated and excite the PrF3 luminescent center.

When the excited luminescent center returns to the ground state, white light with a wide spectrum width of 460 to 800 nm in wavelength is produced as shown in FIG. This white light passes through the color filter layers 4r14g, 4b above each light-emitting pixel E, and becomes a red, green, or blue light-emitting color.

Thus, by appropriately selectively energizing the transparent electrode 2 and the back electrode 3, a desired color, which is a combination of the three primary colors of red, green, and blue, can be obtained at a desired position.

A light emitting element having such a structure has a relatively simple structure and is excellent in productivity.

The color filter layer can also be formed on the lower surface of the glass substrate. This is shown in FIG. In the figure, color filter layers 4r and 4g are formed on the lower surface of a glass substrate 5, and a transparent electrode 2, an insulating layer 61, and a light emitter layer 1 are formed on the lower surface of the color filter layer 4r14Q via a buffer layer 64.
, the buffer layer 63, the insulating layer 62, and the back electrode 3 are formed in this order. Such a structure also provides the same effects as the above embodiment, and also improves durability and reliability since the color filter layer does not come into direct contact with the atmosphere.

In each of the above embodiments, the light emitted from the light-emitting pixel gradually diverges as it travels toward the color filter layer, so the contrast ratio increases if the area of the color filter layer is larger than that of the light-emitting pixel. .

Further, the color filter layer may be formed by an electrodeposition method, a vacuum evaporation method, a printing method, a photosensitive film method, etc. in addition to the dyeing method described above.

Generally speaking, the luminous efficiency of blue light in the light emitter layer is usually inferior to that of red and green, so if the transmittance of the blue color filter layer is increased compared to other color filter layers, the three colors can be made to have almost the same tone. It can be done.

If full color reproduction is not required, the color filter layer may only be red and green, for example.

FIG. 4 shows a third embodiment of the invention. In the figure,
Color filter layers 4r and 4G formed on the glass substrate 5
, 4b are framed by a black layer 9 formed between them. The black layer 9 is formed by coloring an organic thin film black. According to this structure, the adjacent color filter layers 4r
Leakage of light between 14g and 4b can be prevented, and the contrast ratio of color development is greatly improved.

The black layer may be formed on the lower surface of the glass substrate, as shown in FIG. In the figure, PbTe, Pb5e, HgTe, 1-ICISe, etc., which have a small forbidden band width that absorbs all of the visible light range, are formed on the lower surface of a glass substrate 5 by sputtering, vapor deposition, etc., and a lattice pattern is formed by photolithography. The above-mentioned black layer 9 is the same. The black layer 9 is positioned corresponding to the gap between each of the color filter layers 4r, 4g, and 4b. Such a structure also provides the same effects as the above embodiment.

[Brief explanation of the drawing]

1 and 2 show a first embodiment of the present invention, FIG. 1 is a partial cross-sectional perspective view of a light emitting element, FIG. 2 is an emission spectrum diagram of a light emitting layer, and FIG. 3 is a diagram of a light emitting element according to the present invention. A cross-sectional view of a main part showing a second embodiment, FIG. 4 is an overall perspective view of a light emitting device showing a third embodiment of the present invention, and FIG. 5 is a cross-sectional view of a light emitting device showing a fourth embodiment of the present invention. FIG. 3 is a partially sectional perspective view. 1... Light emitter layer 2... Transparent electrode (parallel electrode) 3... Back electrode (parallel electrode) 4r, 4q, 4b... Color filter layer 5...
...Glass substrate 61.62...Insulating layer 9...Black layer 10 Connection 2vJ 400 600 800 +c00 length (nm
) Pavilion 3 Page 4 Figure 5

Claims (4)

[Claims] (1) Striped parallel electrodes are formed above and below across the luminescent layer that emits white light when an electric field is applied, and these upper parallel electrodes and lower parallel electrodes are arranged in a direction that intersects with each other, and one is placed at each intersection. 1. A thin film light-emitting device characterized in that a portion of a light-emitting layer is used as a light-emitting pixel, and color filter layers that selectively transmit a predetermined color are formed alternately on adjacent light-emitting pixels. (2) The thin film light emitting device according to claim 1, wherein the color filter layer selectively transmits red, green or blue. (3) The thin film light emitting device according to claim 1, wherein the light emitting layer is formed by mixing SmF_3 into ZnS. (4) The thin film light emitting device according to claim 1, wherein a black layer is interposed between the adjacent color filter layers.