JP2000173087A - Light writing/reading device and memory device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an element that can be oscillated with a shorter wavelength, can be manufactured easily, and has a high productivity by setting the refractive index of an active layer larger than that of a clad layer in an organic semiconductor laser where an organic electroluminescence light-emitting element has the clad and active layers. SOLUTION: An organic semiconductor laser is composed of an anode 11, a first clad layer 12, an active layer 13, a second clad layer 14, and a cathode 15. The refractive index of the clad layer 12 and 14 is smaller than that of the active layer 13, and the ratio where evanescent waves being generated by the active layer 13 are transmitted through the clad layers 12 and 14 is set to 50% or less for the film thickness of the clad layers 12 and 14. A compound with hole transport unit and a dopant for oxidizing the hole transport unit are added so that the hole exceeding 20 mA/cm2 can be injected under an electric field of 3×10E5V/cm for the first clad layer 12, thus obtaining an organic semiconductor laser for oscillating a laser with a short wavelength with a simple process.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a memory device used in a computer or the like and a writing / reading device using light used in the memory device. (Also referred to as an element).

[0002]

2. Description of the Related Art In recent years, the spread of computers and the improvement of performance thereof have been remarkable, and accordingly, there has been an urgent need for memory devices to have high speed and large capacity.

[0003] At present, as a large-capacity memory device, a device using light for writing and reading of an optical disk or a magneto-optical disk is often used, and an inorganic semiconductor laser element is mainly used as a light source thereof.

However, the inorganic semiconductor laser element has a relatively long oscillation wavelength of about 620 to 800 nm, and it is difficult to increase the recording density.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a writing / reading light source such as an optical disk or a magneto-optical disk which uses light for writing / reading among large-capacity memory devices. An object of the present invention is to provide an element which is easy to manufacture and has high productivity, and to increase the recording density of a memory.

[0006]

This object is achieved by applying the organic semiconductor laser using the organic EL according to the present invention to a write / read light source such as an optical disk or a magneto-optical disk. . That is, an organic semiconductor laser capable of laser oscillation of a short wavelength can be realized by a very simple process, thereby contributing to an improvement in performance, an improvement in productivity, and an expansion of an application range.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, a specific configuration of the present invention will be described in detail.

FIG. 1 is a sectional view showing an embodiment of an organic semiconductor laser used in an optical writing / reading apparatus and a memory device according to the present invention. In the figure, 11 is an anode, 1
2 is a first cladding layer, 13 is an active layer, 14 is a second cladding layer, and 15 is a cathode. Although one of the first and second cladding layers may be omitted, it is preferable to provide both of them. When laser oscillation is performed by optical excitation, both electrodes may be omitted.

Here, each of the cladding layers 12 and 14 has a refractive index smaller than that of the active layer, and a thickness of the cladding layer is such that an evanescent wave generated from the active layer is transmitted through the cladding layer at a rate. It was set to be 50% or less. The first cladding layer is 3 × 10E5V
A compound having a hole transport unit and a dopant capable of oxidizing the hole transport unit were added so that holes of 20 mA / cm 2 or more could be injected under an electric field of / cm.

With the above configuration, an organic semiconductor laser capable of oscillating a short-wavelength laser with a simple process has been realized. The present invention uses this as a light source element to constitute a reading or writing / reading apparatus for an optical disk or a magneto-optical disk, or to realize a memory device using the same, thereby contributing to an increase in storage density. is there.

Embodiment 1 Hereinafter, the present invention will be described with reference to the drawings. FIG. 2 is a conceptual diagram showing an optical writing / reading device as one embodiment of the present invention. The optical writing / reading device shown in FIG. 2 uses a laser light source 21 using an organic EL, a collimator lens 22, a beam splitter 23, an objective lens 24, a condensing (light receiving) lens 25, a pin photodiode, And the like. Then, an emission path to the light source 21, the collimator lens 22, the beam splitter 23, the objective lens 24, and the optical disk 27 is formed.
7, a reflection path to the objective lens 24, the beam splitter 23, the condenser lens 25, and the photodetector 26 is formed.

By using the method of the present invention, a reading or writing / reading apparatus for an optical disk or a magneto-optical disk using an organic semiconductor laser capable of short-wavelength laser oscillation in a very simple process is realized. It contributes to the improvement of performance, productivity, and expansion of application range.

Although an optical disk is used as a memory medium in this embodiment, the same effect can be obtained by using another medium such as a magneto-optical disk.

(Embodiment 2) A memory device was constructed using the optical writing / reading apparatus of Embodiment 1. By using the present invention, a high-density memory device using a short-wavelength laser beam can be realized in a very simple process, thereby contributing to an improvement in performance, an improvement in productivity, and an expansion of an application range.

[0015]

According to the present invention, it is possible to provide a laser light source element which can oscillate a shorter wavelength, is easy to manufacture, and has high productivity in a large-capacity memory device, thereby increasing the recording density of the memory. Has an effect on

[Brief description of the drawings]

FIG. 1 is a conceptual diagram showing an embodiment of the present invention.

FIG. 2 is a conceptual diagram showing an embodiment of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 11 anode 12 first clad layer 13 active layer 14 second clad layer 15 cathode 21 transparent substrate 16 positive electrode 17 hole injection / transport layer 18 emission and electron injection / transport layer 19 negative electrode 21 laser light source using organic EL 22 Collimator lens 23 Beam splitter 24 Objective lens 25 Condensing (light receiving) lens 26 Photodetector consisting of pin photodiode

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H05B 33/24 H05B 33/24

Claims (13)

[Claims] 1. An optical writing and reading apparatus using light, wherein an organic electroluminescent light emitting element having a light emitting layer between a negative electrode and a positive electrode is used as a light source. Readout device. 2. The optical writing / reading device according to claim 1, wherein the organic electroluminescence light emitting device emits laser light. 3. The organic electroluminescent light emitting device is an organic semiconductor laser having a cladding layer and an active layer, wherein the refractive index of the active layer is larger than the refractive index of the cladding layer, and the thickness of the cladding layer is 3. The optical writing / reading device according to claim 2, wherein a ratio of transmitting an evanescent wave generated from the active layer through the cladding layer is set to 50% or less. 4. The organic electroluminescent light emitting device is an organic semiconductor laser having a first cladding layer, an active layer, and a second cladding layer in this order from the anode side,
The refractive index of the active layer is larger than the refractive index of the first clad layer and the second clad layer, and the thickness of the first clad layer and the second clad layer is the thickness of the evanescent wave generated from the active layer. 3. The optical writing / reading device according to claim 2, wherein the reaching ratio to each electrode is set to be 50% or less. 5. The light according to claim 4, wherein in the organic electroluminescence light emitting device, the first cladding layer can inject holes of 20 mA / cm 2 or more under an electric field of 3 × 10 5 V / cm. Writing and reading device. 6. The organic electroluminescence light emitting device, wherein the first cladding layer contains at least a compound having a hole transport unit and a dopant capable of oxidizing the hole transport unit. The optical writing / reading device according to claim 4. 7. A memory device for performing writing and reading using at least light using an organic electroluminescent light emitting element having a light emitting layer between a negative electrode and a positive electrode as a light source for writing and reading using light. A memory device characterized by having been. 8. The memory device according to claim 7, wherein said organic electroluminescence light emitting element emits laser light. 9. The organic electroluminescence light emitting device is an organic semiconductor laser having a cladding layer and an active layer, wherein the refractive index of the active layer is larger than the refractive index of the cladding layer, and the thickness of the cladding layer is 9. The memory device according to claim 8, wherein a ratio of transmitting an evanescent wave generated by the active layer through the cladding layer is set to 50% or less. 10. The organic electroluminescent light emitting device is an organic semiconductor laser having a first cladding layer, an active layer, and a second cladding layer in this order from the anode side, wherein the refractive index of the active layer is the first cladding layer. The thickness of the first cladding layer and the second cladding layer is larger than the refractive index of the cladding layer and the second cladding layer, and the ratio of the evanescent wave generated from the active layer reaching each electrode is 50% or less. 9. The method according to claim 8, wherein the setting is made to be as follows.
The memory device as described. 11. The memory according to claim 10, wherein in the organic electroluminescence light emitting device, the first cladding layer can inject holes of 20 mA / cm 2 or more under an electric field of 3 × 10 5 V / cm. device. 12. The organic electroluminescent light emitting device, wherein the first cladding layer contains at least a compound having a hole transport unit and a dopant capable of oxidizing the hole transport unit. The memory device according to claim 10. 13. The memory device according to claim 7, wherein the memory medium used in the memory device is an optical disk or a magneto-optical disk.