JPH0557953A - Optical printer head - Google Patents

Abstract

PURPOSE:To simplify a structure of a circuit by performing required optical writing or printing at extremely high speed by a method wherein a data electrode of each one end surface light emitting type EL element composing an one end surface light emitting type EL element array is so constructed as to be respectively and directly driven. CONSTITUTION:The title optical printer head is composing by arranging integrally EL elements 2 composing one end surface light emitting type EL array of which a main scan electrode is common on a specific surface of an insulating substrate 1 composed of a glass plate or the like. The EL element 2 is so constructed as to integrate by laminating a data electrode 2a, an insulating material layer 2b, an EL light emitting layer 2c, an insulating material layer 2d, and a main scan electrode layer 2e. Then, a data electrode drive circuit 3 containing a thin film transistor 3a composed of polycrystal silicon as an active layer is arranged on an opposite side to a light emitting end surface of the EL element array on the substrate 1, and the thin film transistor 3a is electrically connected to the data electrode layer 2a of the EL element 2 via a contact hole of the thin film transistor 3a.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical printer head using an EL element array of one-side light emitting type, and more particularly to an optical printer head which is compact and capable of high-speed printing.

[0002]

2. Description of the Related Art An electrophotographic page printer is known as a printer for transmitting electrically processed information in the form of a print. That is, a printer that charges a photosensitive member, then optically writes on the charged photosensitive member according to print information, forms an electrostatic latent image on the surface of the photosensitive member, and visualizes the electrostatic latent image with toner. Being developed.

As a method of optically writing print information to the charged photosensitive member, an optical printer head using an EL element array of one end surface emitting type has been attracting attention (Japanese Patent Laid-Open No. 2-158361). That is, the light emission of the EL light-emitting layer when a required voltage is applied to a pair of electrodes in which the EL light-emitting layer is sandwiched by the insulating layers is totally reflected at the interface with the insulating layer, and the EL light-emitting layer is then reflected. A plurality of EL elements, each of which is confined inside and configured to guide and radiate to one end face side, are arranged in an array, and a pair of electrodes of each EL element (main scanning electrodes formed in a matrix). And the data electrode), the optical printer head is configured to selectively apply a required voltage to the matrix, and the configuration is relatively simple, and not only the occurrence of printing unevenness is reduced, but also
Since it is economical in terms of cost, it has received a lot of attention from a practical point of view.

[0004]

However, in the case of the optical printer head having the above-mentioned structure, the one-end surface-emitting EL element array is divided into fixed blocks for the so-called matrix driving, and the one-end surface-emitting EL element is formed. Since the element emits light, there is a problem that the required optical writing / printing time is necessarily delayed. Further, in the case of the matrix drive circuit, since the number of main scanning electrodes is large, the matrix drive circuit inevitably becomes long, and problems of stray capacitance of wiring and resistance occur. In order to avoid this problem, if the width of the main scanning electrode is widened, the area where the main scanning electrode is formed becomes wider, which causes a problem that the compactness of the optical printer head is impaired.

The present invention has been made in view of the above circumstances, and an object thereof is to provide an optical printer head which is capable of high-speed printing and is compact.

[0006]

SUMMARY OF THE INVENTION An optical printer head according to the present invention comprises a substrate and an end surface emitting type EL element array having a common main scanning electrode which is integrally arranged on a predetermined surface of the substrate. And a data electrode driving circuit including a thin film transistor of polycrystalline silicon integrally disposed on a predetermined surface of the substrate on the side opposite to the light emitting end surface of the EL element array. Each E forming an element array
The data electrode driving circuit is connected to the data electrode of the L element via a polycrystalline silicon-based thin film transistor.

[0007]

The optical printer head according to the present invention has the one end surface emitting type E
Since each EL element forming the L element array is connected directly through a polycrystalline silicon thin film transistor included in the data electrode driving circuit and is directly driven, it is divided as compared with the case of the divided driving method. The printing speed is improved by that amount. In addition, since the number of main scanning electrodes is the same in common with the direct driving method, it is sufficient to reduce the area required for forming the main scanning electrodes, and the optical printer head can be made compact.

[0008]

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

FIG. 1 is a cross-sectional view showing the structure of the main part of an example of an optical printer head according to the present invention.
Is an insulating substrate, for example, a glass plate having a thickness of about 1.1 mm, a width of about 0.5 cm, and a length of about 30 cm, and 2 is one end face having a common main scanning electrode integrally disposed on a predetermined surface of the glass plate 1. This is an EL element of one end surface emitting type which constitutes a light emitting type EL element array. Here, the EL device 2 of the one-sided light emitting type has a data electrode layer 2a, a first insulator layer (dielectric layer) 2b, an EL light emitting layer 2c, and a second insulator on the surface of a predetermined area of the glass plate 1. The layer (dielectric layer) 2d and the common main scanning electrode layer 2e are laminated and integrated. The data electrode layer 2a is formed separately (independently) for each EL element 2 of one edge emitting type which constitutes the one edge emitting EL element array, but the main scanning electrode layer 2e is shown in FIG. One-sided emission type EL, as shown in plan view
All one-sided-emission-type EL elements 2 constituting the element array
Is formed in a common form.

Reference numeral 3 is a data electrode driving circuit including a thin film transistor 3a having polycrystalline silicon as an active layer,
The thin film transistor of the polycrystalline silicon type is provided integrally on a predetermined surface of the substrate 1 on the side opposite to the light emitting end surface of the EL element array, close to the EL element array, and through the contact hole 3b. The switching element) 3a and the data electrode layers 2a of the EL elements 2 of the one-side surface emitting type are electrically connected directly. That is, as shown in FIG. 3, a shift register 3c for flowing a desired print information signal by a switching action, a latch 3d for storing / transferring the print information signal from the shift register 3c, and a logic circuit responsive to an output from the latch 3d. The data electrode driving circuit 3 including a thin film transistor 3e and a polycrystalline silicon thin film transistor 3a that performs a switching operation by the logic circuit 3e is connected to the thin film transistors 3a of the pair of polycrystalline silicon, and each end surface emitting type EL is driven. The element 2 is electrically connected to the data electrode layer 2a.

Next, an example of a manufacturing means of the optical printer head having the above-mentioned structure will be described.

For example, a glass plate 1 having a thickness of about 1.1 mm, a width of about 5 cm and a length of about 30 cm is prepared, and a data electrode including a thin film transistor 3a having polysilicon as an active layer is provided on a predetermined region surface of the glass plate 1. The drive circuit 3 is integrally formed. Then, on the surface of the glass plate 1 on which the data electrode driving circuit 3 including the thin film transistor 3a is integrally formed, the data electrode layer 2a of each EL element 2 constituting the one-end-emission EL element array is formed by Cr-Au by, for example, sputtering means. Is formed into a two-layer structure. In forming this data electrode layer 2a,
One end of the data electrode layer 2a is extended, and for example, a polycrystalline thin film transistor (switching element) located on the final stage side of the data electrode driving circuit 3 (the one-end surface-emitting type EL element 2 side) via a contact hole 3b. ) Make electrical connection with 3a. Here, the reason why the data electrode layer 2a is formed in the two-layer structure of Cr-Au is to consider the processing temperature in the EL element 2 structure thereafter.

Then, on the formed data electrode layer 2a, a first insulating layer 2b made of SiON, an El light emitting layer (eg Mn-doped ZnS) 2c, and a second insulating layer 2d made of SiON are formed on the formed data electrode layer 2a by, for example, sputtering. Are sequentially deposited and then pixels are formed by so-called ion beam etching or the like, and then, for example, Al is sputtered to form the common main scanning electrode layer 2e and the wiring of the data electrode driving circuit 3 at the same time. An optical printer head of edge-emitting type EL element array type, compact, and capable of high-speed printing can be obtained.

[0014]

As described above, in the optical printer head according to the present invention, the data electrodes of the EL elements of one edge emitting type which constitute the one edge emitting EL element array are
Since they are driven separately and directly, the required optical writing or printing can be achieved at a significantly higher speed than the conventional matrix division driving system. Also, the number of main scanning electrodes is 1
Since a book is sufficient, the circuit configuration can be simplified and the size can be easily reduced. In other words, it can be said that the printer using this type of optical printer head can sufficiently meet the practically desired high-speed printing, improvement in printing resolution, and size reduction.

[Brief description of drawings]

FIG. 1 is a sectional view showing a configuration example of a main part of an optical printer head according to the present invention.

FIG. 2 is a plan view showing a configuration example of a main part of an optical printer head according to the present invention.

FIG. 3 is a block diagram showing an example of a data electrode driving circuit of the optical printer head according to the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Substrate 2 ... EL element of one-end light emitting type 2a ... Data electrode (data electrode layer) 2b ... First insulating layer (dielectric) 2c ... EL light emitting layer 2d ... Second insulating layer (dielectric) 2e ... Main scanning electrode (common main scanning electrode layer) 3
Data electrode drive circuit 3a Polycrystalline silicon thin film transistor 3b Contact hole 3c Shift register 3d Latch 3e Logic circuit

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI Technical display location G03G 15/04 116 9122-2H H01L 29/784 H05B 33/00 8815-3K 33/08 8815-3K

Claims (1)

[Claims] 1. A one-end surface light emitting type EL element array having a substrate and a main scanning electrode integrally provided on a predetermined surface of the substrate, and the main scanning electrode is located on the opposite side of the light emitting end surface of the EL element array. And a data electrode driving circuit including a polycrystalline silicon thin film transistor integrally arranged on a predetermined surface of the substrate, wherein the data electrodes of each EL element forming the one-end surface light emitting type EL element array are An optical printer head having a structure in which a data electrode driving circuit is connected through a crystalline silicon thin film transistor.