JPH10321943A - Thin color display using vertical cavity surface emitter laser device having monochromatic emission spectrum - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make a device thin, eliminate vacuum and high voltage in the device, and reduce power consumption, by arranging a plurality of vertical cavity surface emitter laser elements having a monochromatic emission spectrum in one plane and, controlling these elements individually to emit light. SOLUTION: Vertical cavity laser elements 23 as semiconductor laser elements formed on a substrate 1 are individually controlled in one plane to emit light, and then fluorescent materials 24 to correspond to the respective laser elements individually emit visible light (i.e., red, green or blue light) characteristic to the fluorescent materials 24. By arranging the fluorescent materials 24 in such a manner that the ones adjacent to each other or close to each other may emit lights of different colors, the information having various colors can be displayed. Thus, by arranging a plurality of vertical cavity surface emitter laser elements 23 having a monochromatic emission spectrum of an ultraviolet region in one plane and controlling them individually to emit light, the display in color is available.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a thin color display device using a vertical cavity surface emitting laser device having a single color emission spectrum.

[0002]

2. Description of the Related Art Hitherto, many color display devices have been proposed which display image information in color according to supplied electric signals. As the color display device, a cathode ray tube (CRT) in which a phosphor excited by an electron beam generates visible light, a thin liquid crystal display device (LC)
D) As a self-luminous flat-panel display device, a plasma display tube (PDP) in which a phosphor excited by plasma emits visible light emits light of an emitter excited by an electron beam, similarly to a CRT. A flat emission type flat display element (FED) capable of realizing the same characteristics as a CRT in a thin shape by using a large number of manufactured electron beam emitting elements, and a light emitting diode (LED) of a solid state element having excellent luminous efficiency and color purity.
Are arranged in a large number.

[0003]

However, the CRT
In the case of, the device tends to be large and it is difficult to make it thin, it is necessary to evacuate the inside of the display tube to emit the electron beam, and it is necessary to set a high voltage when accelerating the electron beam. In addition, there is a disadvantage that power consumption is increased. In the case of an LCD, an illumination device is required because the LCD is not a self-luminous element, and the reaction speed is relatively slow.
Since the operable temperature range is narrow and color display is performed by extracting necessary light from the light of the lighting device, there is a disadvantage that energy efficiency is deteriorated. In the case of the PDP, it is difficult to extend the life because the inside of the device is easily damaged during plasma emission, a high voltage is required when plasma is generated, and it is necessary to evacuate the display tube to generate plasma. Have. Also, in the case of FED, it is necessary to evacuate the display tube to emit an electron beam,
There is a disadvantage that it is necessary to increase the voltage when accelerating the electron beam. Also, when using a device in which a large number of LEDs are arranged, individually manufactured LEDs for multicolor display
However, it is difficult to arrange each element at minute intervals, and it is necessary to manufacture elements that emit light of different colors collectively in a plane, and it is necessary to use a manufacturing technology optimized for each material. Therefore, it is difficult to realize a high-definition and high-resolution flat-panel color display device.

An object of the present invention is to provide a flat-panel color display device which does not have the above-mentioned disadvantages, that is, it is easy to make the device thinner, and it is not necessary to evacuate the inside of the device and to use a high voltage. , Low power consumption, no need for lighting equipment, relatively fast reaction speed, wide operating temperature range, long life, high-resolution Another object of the present invention is to provide a flat color display device with high resolution.

[0005]

According to the present invention, a thin color display device using a vertical cavity surface emitting laser device having a single color emission spectrum according to claim 1 has a plurality of single color emission spectra. The vertical cavity surface emitting laser elements are arranged in a plane, and the vertical cavity surface emitting laser elements are individually controlled to emit light to perform color display. .

According to the thin color display device using the vertical cavity surface emitting laser device having a single color emission spectrum according to claim 1, a plurality of vertical cavity surface emitting laser devices having a single color emission spectrum are provided. Are arranged in a plane, and the vertical cavity surface emitting laser elements are individually controlled to emit light, thereby performing color display. Since the vertical cavity surface emitting laser elements are arranged in a plane as described above, the device can be easily made thin. Further, since a solid-state device such as a vertical cavity surface emitting laser device is used, it is not necessary to maintain a vacuum. Also, the required drive voltage
Since the emission energy can be reduced to about the level of the vertical cavity surface emitting laser element, a high voltage is not required and power consumption is reduced. In addition, since a self-luminous element such as a vertical cavity surface emitting laser element is used, an illumination device is not required. Further, since the color display device is formed using the vertical cavity surface emitting laser element, the reaction speed is relatively fast, and the operable temperature range is wide. In addition, since the element is less likely to be damaged during driving, the life can be extended. Furthermore, since only the vertical cavity surface emitting laser element having a single color emission spectrum is arranged,
The elements can be manufactured collectively in a plane at minute intervals, and a high-definition and high-resolution flat-panel color display device can be realized.

According to a second aspect of the present invention, there is provided a thin color display device using a vertical cavity surface emitting laser device having a single color emission spectrum according to claim 2, wherein the single color emission spectrum is in an ultraviolet region, A phosphor of an arbitrary color is provided for each of the surface emitting laser elements, and the corresponding phosphor is excited by ultraviolet light emitted from each vertical cavity surface emitting laser element to generate visible light. It is characterized by the following.

According to the thin color display device using the vertical cavity surface emitting laser device having a single color emission spectrum according to the second aspect, the vertical cavity surface emitting laser device has a single color emission spectrum in an ultraviolet region. Are provided for each of the above, and the corresponding phosphor is excited by ultraviolet light emitted from each vertical cavity surface emitting laser element to generate visible light. In the case of a vertical cavity surface emitting laser device in the ultraviolet region, the required driving power is 10 V
It can be: Therefore, driving at a lower voltage is possible as compared with a conventional color display device such as a PDP, and power consumption can be reduced.

According to a third aspect of the present invention, there is provided a thin color display device using a vertical cavity surface emitting laser device having a single color emission spectrum according to the third aspect of the present invention, wherein the single color emission spectrum is in a blue region, and at least a part of the light emission spectrum is a blue region. The vertical cavity surface emitting laser device other than the vertical cavity surface emitting laser device used to generate blue light using blue light emitted from the vertical cavity surface emitting laser device for display as visible light A phosphor of an arbitrary color is provided for each of the elements, and the corresponding phosphor is excited by blue light emitted from each vertical cavity surface emitting laser element to generate visible light other than blue light. It is characterized by having done.

According to the thin color display device using the vertical cavity surface emitting laser device having a single color emission spectrum according to the third aspect, the single color emission spectrum is set to a blue region, and at least a part of the vertical cavity type light emitting device is used. The blue light emitted from the surface emitting laser element is used for display as visible light, and any of the vertical cavity surface emitting laser elements other than the vertical cavity surface emitting laser element used to generate the blue light is used. Are excited by the blue light emitted from each vertical cavity surface emitting laser element to excite the corresponding phosphor to generate visible light other than blue light.
In the case of a vertical cavity surface emitting laser device in the ultraviolet region, the required driving power can be reduced to 10 V or less. Therefore, driving at a lower voltage is possible as compared with a conventional color display device such as a PDP, and power consumption can be reduced. In addition, since it is not necessary to use a phosphor for all the vertical cavity surface emitting laser elements, the apparatus can be manufactured at a lower cost as compared with a case where a single color emission spectrum is in an ultraviolet region.

According to a fourth aspect of the present invention, there is provided a thin color display device using the vertical cavity surface emitting laser device having a single color emission spectrum according to the fourth aspect of the present invention, wherein the vertical cavity surface emitting laser device includes a semiconductor multilayer film reflection device. It is characterized by including a mirror.

According to a thin color display device using a vertical cavity surface emitting laser device having a single color emission spectrum according to the fourth aspect, a semiconductor multilayer film reflecting mirror included in the vertical cavity surface emitting laser device is used. The vertical cavity surface emitting laser device can be easily manufactured, the luminous efficiency can be increased, and the power consumption can be further reduced.

According to a fifth aspect of the present invention, a thin color display device using a vertical cavity surface emitting laser device having a single color emission spectrum according to claim 5 is opposed to an emission end face of the vertical cavity surface emitting laser device. A substrate is provided, and of this substrate,
The phosphor is provided on a surface facing an emission end face of the vertical cavity surface emitting laser element.

According to a fifth aspect of the present invention, there is provided a thin color display device using a vertical cavity surface emitting laser device having a single color emission spectrum, wherein a substrate opposed to an emission end face of the vertical cavity surface emitting laser device is provided. A phosphor is provided on the surface of the substrate facing the emission end face of the vertical cavity surface emitting laser device. With such a configuration, it is possible to more easily realize a thin device.

According to a sixth aspect of the present invention, there is provided a thin color display device using a vertical cavity surface emitting laser device having a single color emission spectrum according to the present invention, wherein each of the phosphors corresponds to the corresponding vertical cavity type. The surface emitting laser element is provided on each of the emission end faces.

According to a thin color display device using a vertical cavity surface emitting laser device having a single color emission spectrum according to claim 6, each of the phosphors is provided with a corresponding vertical cavity surface emitting laser device. Are respectively provided on the emission end faces of. With such a configuration, a thin device can be realized more easily.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A thin color display device using a vertical cavity surface emitting laser device having a single color emission spectrum according to the present invention will be described in detail with reference to the drawings. In the drawings, the same members are given the same numbers.
FIG. 1 is a conceptual diagram of the configuration of a first embodiment of a thin color display device using a vertical cavity surface emitting laser device having a single color emission spectrum according to the present invention. In FIG. 1, vertical cavity surface emitting laser elements 2 to 5 having a single color emission spectrum in the ultraviolet region are formed on a substrate 1 in a matrix, and these vertical cavity surface emitting laser elements 2 to 5 are formed. Light-emitting bodies 7 to 22 arranged in rows and columns corresponding to these vertical cavity surface emitting laser elements 2 to 5 and the like are formed on a substrate 6 facing the emission end face such as 5. The space between the vertical cavity surface emitting laser devices 2 to 5 and the like in the row and column directions and the space between the light emitters 7 to 22 in the row and column directions are respectively from several μm depending on the size and resolution of the device. Select about several hundred μm.

In the case of the present embodiment, the phosphors 7, 10, 1
3, 16, 19, and 22 are red phosphors, phosphors 8, 11, 14, 17, and 20 are green phosphors, and phosphors 9, 12, 15, 18, and 21 are blue phosphors. . These phosphors 7 to 22 are respectively excited by ultraviolet light emitted from the corresponding vertical cavity surface emitting laser elements 2 to 5 to generate red, green and blue visible light. Thus, the red, green or blue phosphors 7 to
By arranging the pixels 22 at minute intervals in the row direction and the column direction, three primary colors of light can be generated at minute intervals, and color display can be performed.

The vertical cavity type light emitting laser devices 2 to 5 for ultraviolet light used here, that is, the material of the light emitting device is as follows.
It is reported that a compound semiconductor of aluminum nitrogen, indium nitrogen, and gallium nitrogen and a mixed crystal thereof can be used. In practice, a high-luminance surface-emitting diode is used, and it has been reported that this can be realized also as a blue semiconductor laser. .

As a vertical cavity type light emitting laser device as a laser light source used in the present invention, a single color device may be manufactured. Arranging a large number of monochromatic vertical cavity type light emitting laser elements can be realized by a normal semiconductor manufacturing process, and has already been realized as a two-dimensional array of vertical cavity type surface emitting semiconductor lasers. Also, in the full color devices CRT, PDP, FED, etc. which have already been developed, the color of each element is made different by using a fluorescent material.
In D, the color of each element is made different by using a color filter. For these, a technique has been put to practical use in which different colors are easily adjacent to each other at minute intervals by applying a printing technique. The phosphors 7 to 22 used in the present embodiment are manufactured in the same manner.

FIG. 2 is a partial side view of a first embodiment of a thin color display device using a vertical cavity surface emitting laser device having a single color emission spectrum according to the present invention. In FIG. 2, a vertical cavity laser element 23 corresponds to one of the vertical cavity laser elements 2 to 5 and the like in FIG.
1. The red, green or blue phosphors 7 to 2 of FIG.
It corresponds to one of the two.

The vertical cavity laser element 23 is composed of two kinds of semiconductor materials having different refractive indices, each having a desired emission wavelength.
Clad layers 25a and 25b alternately laminated with a film thickness of / 4
And an active layer 26 interposed between the cladding layers 25a and 25b.
Are connected to electrodes 27 and 28, respectively. These clad layers 25a and 25b function as semiconductor layer film reflecting mirrors that strongly reflect light by the interference effect of the semiconductor materials stacked alternately. In the present embodiment, the cladding layer 25a
Is formed of a p-type semiconductor material, and the cladding layer 25b is formed of an n-type semiconductor material, so that the vertical cavity laser element 23 has a semiconductor laser diode structure.

Also, when the vertical cavity type laser element 23 emits ultraviolet light, it controls whether or not the vertical cavity type laser element 23 emits ultraviolet light by controlling on / off of the electrodes 27 and 28. At the same time, the light output is controlled by controlling the current injected into the vertical cavity laser element 23.

The operation of the embodiment will be described. When ultraviolet light is output from the emission end face of the vertical cavity laser element 23, a voltage is applied to the vertical cavity laser element 23 so that a current flows from the cladding layer 25a to the cladding layer 25b. Is spontaneously emitted in the active layer, and the spontaneous light is amplified by the cladding layer 25a,
The laser beam is obtained by being returned by the reflector structure 25b. In order for this emission wavelength to be ultraviolet light, the active layer 26 must be made of a semiconductor material having a forbidden band width corresponding to ultraviolet light. Since the cladding layers 25 a and 25 b having the reflecting mirror structure sandwich the active layer 26 in a direction perpendicular to the substrate 1, ultraviolet light is emitted perpendicular to the substrate 1.

The ultraviolet light that has been laser-oscillated is incident on a phosphor 24 corresponding to the vertical cavity laser element 23 and is absorbed. Since the excitation light energy of the ultraviolet light is larger than the emission energy inherent in the phosphor, the phosphor 24 that has absorbed the ultraviolet light
Emits with visible light (red, green, or blue in this embodiment) specific to the phosphor.

Each of the vertical cavity laser elements 23 as the semiconductor laser elements on the substrate 1 is controlled to emit light in a planar manner independently of each other. Visible light of color (ie, red,
Green or blue) is emitted. By making the emission color of a phosphor adjacent to or adjacent to a certain phosphor a phosphor of a different emission color from the emission color of the phosphor, information having various colors can be displayed. .

According to the present embodiment, a plurality of vertical cavity surface emitting laser elements having a single color emission spectrum in the ultraviolet region are arranged in a plane, and these vertical cavity surface emitting laser elements are individually arranged. Since the vertical cavity surface emitting laser device is arranged in a plane by performing color display by controlling the light emission in a controlled manner, the device can be easily made thin. Further, since a solid-state device such as a vertical cavity surface emitting laser device is used, it is not necessary to maintain a vacuum.
Further, since the required driving voltage can be reduced to about the emission energy of the vertical cavity surface emitting laser element (10 V or less), a high voltage is not required and power consumption is reduced. In addition, since a self-luminous element such as a vertical cavity surface emitting laser element is used, an illumination device is not required. Further, since the color display device is formed using the vertical cavity surface emitting laser element, the reaction speed is relatively fast, and the operable temperature range is wide. In addition, since the element is less likely to be damaged during driving, the life can be extended. Since only vertical cavity surface emitting laser elements having a single color emission spectrum are arranged, the elements can be manufactured collectively in a plane at minute intervals, realizing a high-definition and high-resolution flat-panel color display device. can do.

Further, the optical output of the vertical cavity surface emitting laser device is enhanced by the semiconductor multilayer film reflecting mirror included in the vertical cavity surface emitting laser device, the required driving voltage is further reduced, and the power consumption is reduced. It becomes even smaller. Further, by providing a substrate facing the emission end face of the vertical cavity surface emitting laser element and providing a phosphor on a surface of the substrate facing the emission end face of the vertical cavity surface emitting laser element, Can be more easily realized.

Further, since it is only necessary to form a vertical oscillator type surface emitting laser element which emits at the same or similar emission wavelength in a planar shape, semiconductor elements which emit different emission colors having different characteristics are collectively manufactured. This is advantageous because it is difficult. At present, a blue light emitting semiconductor laser has already been developed, and it is considered that an ultraviolet semiconductor laser can be realized by slightly changing the material of the active layer. It is also shown that this can be theoretically realized as a surface emitting laser.

As a technique for making the color of light emitted by a light emitting body adjacent to or adjacent to a light emitting body different from the color of light emitted by a certain light emitting body, the same forming method as that of a color display device developed so far is applied. It is effective because it does not require new technology.

It is considered that such a vertical cavity surface emitting laser device that generates ultraviolet light can reduce the required driving voltage to about the emission energy. Even a blue semiconductor laser that has already been reported is 10 V or less. Therefore, such a vertical cavity surface emitting laser device can be driven at a lower voltage than a plasma device or the like. Further, since such a vertical cavity surface emitting laser element is a solid state light emitting element, a vacuum region is not interposed between the light emitting elements and a liquid film such as a liquid crystal is not interposed. Can be easily configured with high reliability.

The advantage of using such a vertical cavity surface emitting laser element as a light source is that, as can be seen from the characteristics of LEDs and semiconductor lasers which are semiconductor light emitting elements which have been practically used, all solid-state elements are used. An object of the present invention is to enable a thin color display device of a self-luminous element having high-speed response, high-efficiency light emission, low-voltage driving, and long life.

Further, according to the present invention, a vertical cavity surface emitting laser device, which is a semiconductor laser capable of collectively manufacturing a very low threshold current, ultra-miniaturization, and a two-dimensional array, is used as a light source. Since the emission angle of the laser light emitted from the vertical cavity surface emitting laser element is narrow, so-called light emission bleeding caused by each laser light overlapping with the adjacent laser light is removed. In addition, since a vertical cavity surface emitting laser device having a single-color emission spectrum is used, so-called spectral bleeding caused by a different emission spectrum is eliminated. Further, by matching the emission wavelength of the emission spectrum with the absorption characteristics of the phosphor, higher emission efficiency can be realized. As described above, the thin color display device using the vertical cavity surface emitting laser device having a single color emission spectrum according to the present invention satisfies many characteristics required for a color display device.

The present invention is not limited to the above-described embodiment, and many modifications and variations are possible. For example, the single-color emission spectrum of the vertical cavity surface emitting laser elements 2 to 5 and the like is set to the blue region, and all of the phosphors 7 to 22 are not arranged. Alternatively, full-color display is enabled by extracting blue light to the outside as a structure for performing necessary diffusion without absorption, and emitting red or green light from a portion where the phosphors 7 to 22 are arranged. .

In FIGS. 2 and 3, the cladding layer 2
5a is formed of a p-type semiconductor material, and the cladding layer 25b is formed of n
Although the cladding layer 25a is formed of an n-type semiconductor material, the cladding layer 25b may be formed of a p-type semiconductor material. Further, the cladding layers 25a, 25
5b functions as a semiconductor layer film reflecting mirror that strongly reflects light by the interference effect of the semiconductor materials stacked alternately, but a reflecting mirror can be formed outside the cladding layer.

Further, in the above-described embodiment, the case of performing full color display has been described. However, the present invention can be applied to a color display device which displays a single color (for example, red, green, blue, etc.). . In this case, color display can be performed by using a structure in which laser light is transmitted as it is or a necessary diffusion is performed so that the laser light is not absorbed without using a phosphor.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram of a configuration of a first embodiment of a thin color display device using a vertical cavity surface emitting laser device having a single color emission spectrum according to the present invention.

FIG. 2 is a partial side view of a first embodiment of a thin color display device using a vertical cavity surface emitting laser device having a single color emission spectrum according to the present invention.

FIG. 3 is a side view of a part of a second embodiment of a thin color display device using a vertical cavity surface emitting laser device having a single color emission spectrum according to the present invention.

[Explanation of symbols]

1,6 substrate 2,3,4,5,23 vertical cavity surface emitting laser device 7,8,9,10,11,12,13,14,15,1
6,17,18,19,20,21,22,24,29
Light-emitting body 25a, 25b Cladding layer 26 Active layer 27, 28 Electrode

Claims (6)

[Claims] 1. A plurality of vertical cavity surface emitting laser elements having a single-color emission spectrum are arranged in a plane, and the vertical cavity surface emitting laser elements are individually controlled to emit light. A thin color display device using a vertical cavity surface emitting laser element having a single-color emission spectrum, which performs display. 2. The single-color emission spectrum is defined as an ultraviolet region, a phosphor of an arbitrary color is provided for each of the vertical cavity surface emitting laser devices, and ultraviolet light emitted from each vertical cavity surface emitting laser device is provided. 2. A thin color display device using a vertical cavity surface emitting laser device having a single color emission spectrum according to claim 1, wherein the corresponding phosphor is excited by light to generate visible light. . 3. The apparatus according to claim 1, wherein the monochromatic emission spectrum is a blue region, and blue light emitted from at least a part of the vertical cavity surface emitting laser device is used as visible light for display, and is used for generating blue light. A phosphor of any color is provided for each of the vertical cavity surface emitting laser elements other than the vertical cavity surface emitting laser element, and blue light emitted from each vertical cavity surface emitting laser element 2. A thin color using a vertical cavity surface emitting laser device having a single color emission spectrum according to claim 1, wherein the corresponding phosphor is excited to generate visible light other than blue light. Display device. 4. The vertical cavity surface emitting laser device according to claim 1,
4. A thin color display device using a vertical cavity surface emitting laser device having a single color emission spectrum according to claim 1, further comprising a semiconductor multilayer mirror. 5. A substrate facing an emission end face of said vertical cavity surface emitting laser element, said phosphor being provided on a surface of said substrate facing said emission end face of said vertical cavity surface emitting laser element. A thin color display device using a vertical cavity surface emitting laser device having a single color emission spectrum according to any one of claims 2 to 4. 6. The vertical cavity surface emitting laser device according to claim 2, wherein each of said phosphors is provided on an emission end face of said vertical cavity surface emitting laser device. A thin color display device using a vertical cavity surface emitting laser element having a single color emission spectrum.