KR100281073B1 - Laser Display Device - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image display apparatus, and more particularly, to an image display apparatus that is lighter and has a simpler driving circuit than a conventional CRT by emitting phosphors using a laser beam. The present invention provides a laser generation unit for generating a laser beam, a laser separation unit for separating the laser beam into three, an optoacoustic modulator for adjusting the intensity of the laser beam according to an image signal, and scanning the laser beam while moving the laser beam horizontally and vertically. And a video display unit for displaying an image by associating a phosphor with a laser beam.

Description

Image display device using laser {Laser Display Device}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a display device, and more particularly, to a display device for emitting fluorescent materials using laser light.

In general, a CRT (Cathode Ray Tube) display device is most commonly used to display an image using a luminescence phenomenon of a phosphor generated by colliding a high-speed electron beam (Beam) from the electron gun to the phosphor coated on the screen.

The structure and operation principle of CRT CRT are as follows. Figure 1 shows the schematic structure of the CRT CRT. Three electron beams 11 are emitted from the electron gun 10 to realize the color of the image. The electron beam emitted from the electron gun passes through the vacuum tube 13 in which the magnetic field 12 generated by the deflection yoke 16 is continuously distributed. The strength and direction of the magnetic field of the vacuum tube is controlled by the drive circuit (not shown in the figure). The electron beam is bent in an appropriate direction by the magnetic field, and the bent electron beam passes through a mesh network called a shadow mask 14. The three electron beams collide with the fluorescent plate 15 attached behind the shadow mask, respectively, to emit light of the red phosphor R, the green phosphor G, and the blue phosphor B formed on the phosphor plate. That is, one electron beam emits one phosphor. The shadow mask serves as a shielding film to prevent the electron beam from accidentally colliding with an adjacent phosphor by an error of magnetic field control.

By the way, the path of the electron beam is adjusted by the control of the electric and magnetic fields continuously distributed in the CRT tube. The prediction of this path is difficult, and the driving circuit for the control is complicated and difficult. Therefore, the CRT display device has a problem that a technical solution for controlling the electric field and the magnetic field formation that can bend the electron beam in any direction must be accompanied.

In addition, the conventional CRT display device must vacuum the space between the electron gun and the phosphor to avoid collision with other materials and prevent oxidation of the phosphor and the shadow mask while the electron beam reaches the phosphor. Thus, the CRT display device is composed of a vacuum tube. By the way, the vacuum glass used to manufacture this vacuum tube is thick and heavy, making it difficult to manufacture large tubes. Therefore, it is very difficult to realize a large screen with a CRT display.

The present invention facilitates the design of the driving circuit by using a laser light which is easy to predict the path due to reflection and refraction instead of the electron beam, which is difficult to predict the path, and realizes a lightweight large screen by eliminating the use of a vacuum tube. The purpose of this invention is to manufacture a display device.

1 is a schematic diagram showing a conventional CRT image display apparatus.

Figure 2 is a detailed view showing a first embodiment of the present invention.

3 is a cross-sectional view showing a laser beam scanned to a phosphor through a shadow mask in the image display device of the present invention.

4 is a schematic view showing a second embodiment of the present invention.

Explanation of symbols for main parts of the drawings

100, 100 ': laser generating unit 110: laser separation unit

111: first semi-transparent mirror 112: second semi-transparent mirror

113: total reflection mirror 120: photoacoustic modulation unit

130: laser deflector 131: rotating mirror

132: galvanometer 140: image display unit

141: shadow mask 141 ': hole of the shadow mask

142: quartz glass 143: phosphor

144: screen glass 150, 150 ': focus lens

160: half parabolic total reflection mirror 200: laser beam

210: first laser beam 210 ': first laser beam having passed through a hole

220: second laser beam 220 ': second laser beam passing through the hole

230: third laser beam 230 ': third laser beam passing through the hole

R, G, B: fluorescent material

The display device of the present invention is characterized by using a laser light having excellent linearity as a light source for emitting light of a phosphor. Looking at the structure of the present invention with reference to the accompanying drawings as follows. That is, according to the present invention, as shown in Fig. 2, the laser generation unit 100 for generating a laser beam, the laser separation unit 110 for dividing the laser beam into three beams of uniform intensity, and three according to a predetermined image signal An Acoustic-Optic Modulator (AOM) 120 that modulates the intensity of each of the two beams, and three beams modulated by the Acoustic-Acoustic Modulator while moving in a horizontal and vertical direction for a predetermined period of time. The laser deflector 130 and an image display unit 140 for displaying an image by scanning the three beams scanned by the laser deflector to the phosphor of the pixel allocated on the screen, respectively. In this case, the laser generation unit for generating a single laser beam may be replaced with a laser generation unit for generating three lasers. In this case, the laser separator does not need to be installed.

Hereinafter, the most preferred embodiments of the present invention will be described with reference to the accompanying drawings.

(Example 1)

Embodiment 1 is a laser generator and the first semi-transparent mirror 111 and the second semi-transparent mirror 112 and the total reflection mirror 113, and the photoacoustic modulator and the rotating mirror 131 as shown in detail in FIG. And a galvanometer 132, and a screen mask 144 coated with a shadow mask 141, a quartz glass 142, and a phosphor 143. In addition, focus lenses 150 and 150 'and a total reflection mirror 160 in the form of a parabola are provided as required for laser beam focusing.

The laser generator generates a helium-cadmium (He-Cd) -based ultraviolet laser. Helium-cadmium-based lasers have maximum output wavelengths in two wavelength bands, the ultraviolet wavelength range of 325 nm to 335 nm and the blue wavelength range of 442 nm, and only the ultraviolet rays can be separated through proper filtering. In Example 1, a helium-cadmium-based ultraviolet laser is used, but any ultraviolet laser may be used as long as the fluorescent material has sufficient power to emit light. In addition, if the fluorescent material can be sufficiently emitted, an infrared laser may be used.

The first semi-transmissive mirror reflects only one third (33.3%) of the laser beam 200 output from the laser generator, and transmits the light amount of the laser beam corresponding to two thirds (66.6%) of the remaining light. The second semi-transmissive mirror reflects only one half (50%) of the laser beam transmitted through the first semi-transmissive mirror, and transmits the light amount of the laser beam corresponding to the other half (50%). Let's do it. In addition, the total reflection mirror reflects all of the laser beam transmitted through the second semi-transmissive mirror. The laser beam (hereinafter referred to as the first laser beam) 210 reflected from the first semi-transparent mirror and the laser beam (hereinafter referred to as the second laser beam) 220 reflected from the second semi-transmissive mirror and the laser beam reflected from the total reflection mirror (Hereinafter, the third laser beam) 230 is incident on the red, green, and blue phosphors, respectively. As a result, the first laser beam, the second laser beam, and the third laser beam all have a light amount corresponding to one third of the laser beam originally generated by the laser generator. In this embodiment, the first semi-transmissive mirror, the second semi-transparent mirror, and the total reflection mirror serve as the laser separation unit 110.

The optoacoustic modulator maps the first laser beam, the second laser beam, and the third laser beam to red, green, and blue image signals, respectively, and changes the intensity of each laser beam according to the image signal. For example, when the first laser beam corresponds to red, the second laser beam corresponds to green, and the third laser beam corresponds to blue, and the image to be displayed on the screen is red, the output of the first laser beam is maximized. The output of the second laser beam and the third laser beam is minimized or there is no output at all. In this way, the intensity of each laser beam is adjusted to express the color of the image.

The three laser beams, which have undergone the optoacoustic modulator, are scanned by the laser deflector 130 through a focus lenz 150 'so that they can be collected at a point on the shadow mask later. In this case, if three laser beams that have undergone the optoacoustic modulator are designed to be able to gather at one point of the shadow mask without passing through the focus lens, it does not need to go through the focus lens.

The laser deflectometer is composed of a rotating mirror 131 of a polyhedron for horizontal scanning and a galvanometer 132 for vertical scanning. The rotating mirror is configured to rotate at a constant speed, which is closely related to the horizontal frequency for displaying an image and the number of surfaces of the rotating mirror. If the present invention is used as an apparatus for constructing an NTSC-type TV screen and the rotating mirror has 24 reflecting surfaces, the rotational speed of the rotating mirror should be about 39,000 rpm when the horizontal frequency is 15.5 kHz. The meter should be configured so that its frequency corresponds to 60 Hz, the vertical frequency of the TV.

The laser beam passing through the laser deflectometer is reflected by the total reflection mirror 160 in the form of a parabola and is scanned onto the screen glass 144 coated with the phosphor. This deflection technology can be sufficiently performed by existing technologies such as a laser TV that implements an image on a screen by using a visible light laser. In this case, if there is no problem in realizing the image even though the total reflection mirror does not go through, the half reflection parabola-shaped total reflection mirror 160 does not need to be installed.

The three laser beams 210, 220, 230 scanned on the screen meet each other at the holes 141 of the shadow mask as shown in Fig. 3, and are scanned in different directions. This shadow mask should consist of a material that blocks light. The function of the shadow mask is to cut the thickness of each of the three laser beams to match the size of the phosphor so that the three laser beams scanned on the screen are not scanned on the portion other than the phosphor in charge. The three laser beams 210 ', 220', and 230 'passing through the shadow mask are respectively scanned by the phosphors R, G, and B in charge thereof, and emit the phosphors.

2, the quartz glass 142 is formed between the shadow mask 141 and the phosphor 143. The screen glass 144 for general screens is in close contact with the opposite surface of the phosphor to which the quartz glass is attached. That is, the phosphor is completely shielded from the outside by quartz glass and ordinary glass. The reason is to prevent the phosphor from being oxidized in air.

The reason why the quartz glass adheres to the surface of the phosphor in the direction in which the laser beam is incident is because the quartz component transmits ultraviolet rays well. If the material has low absorptivity and reflectance to ultraviolet rays and high transmittance, it may not be quartz glass. The reason why ordinary glass is attached to the surface in the direction in which the phosphor emits light is that the light emitted by the phosphor is transmitted through the glass well. If it is a transparent material that transmits light well, it can be used.

The phosphor used in the present embodiment may be any device capable of emitting light when ultraviolet rays are scanned. Generally, ZnS: Ag, ZnS: Ag + pigments are used as blue phosphors, and ZnS: (Cu, Al), ZnS: (Cu, Al) + pigments are used as green phosphors, and red phosphors Y ₂ O ₂ S: Eu, Y ₂ O ₂ S: Eu + pigments and the like are now widely used as monitor phosphors. In the monitor, the electron beam from the electron gun is incident on these phosphors, and the luminescent energy is excited by the kinetic energy to emit blue, green, and red light.

The above-mentioned phosphors have the property of emitting light not only by the electron beam but also by ultraviolet wavelengths of 254 nm and 365 nm. In particular, the light emission effect when the ultraviolet ray of 365 nm is incident is similar to the light emission effect by the electron beam. This fact means that the image implemented on the screen through the emission of the phosphor has sufficient brightness not only by the electron beam but also by the scanning of ultraviolet rays. That is, the display device by ultraviolet rays may have an image similar to that of the existing CRT.

(Example 2)

The present invention may have another embodiment by the structure of the laser generation unit. Unlike Embodiment 1 described above, the second embodiment has a different structure of the laser generating unit, and there is no laser separation unit such as a first semi-transparent mirror, a second semi-transparent mirror, and a total reflection mirror.

Since the operation principle of the remaining portion is the same as in the first embodiment, the description is omitted, and only the main features of the present embodiment are as follows.

In the second embodiment, as shown in Fig. 4, the laser generating unit 100 'generates three laser beams of the first laser, the second laser, and the third laser. Therefore, unlike Example 1, there is no laser separation unit.

The image display device manufactured by the present invention emits phosphors with a laser beam that is superior in straightness, refractive index, and reflectivity as compared to the electron beam used in the CRT, which is a conventional image display device. It has the advantage of being easy. In addition, unlike the glass tube of the CRT, the tube of the image display device manufactured through the present invention does not need a vacuum state, and thus does not need to be made of thick glass, and thus the weight is light. In addition, it has the same level of picture quality as the CRT, and does not require an electromagnetic field forming area, which makes the configuration of a large screen simple.

Claims (10)

A laser generator for generating a laser beam; A laser separation unit dividing the laser beam into three beams having a uniform intensity; An optical acoustic modulator (AOM) for modulating the intensity of each of the three beams divided by the laser separation unit according to a predetermined image signal; A laser deflector scanning three beams modulated by the photoacoustic modulator while moving horizontally and vertically in accordance with horizontal and vertical synchronization; And, And an image display unit for displaying an image by mapping the three beams scanned by the laser deflector to respective phosphors of blue, green, and red of the pixel. The laser image display apparatus according to claim 1, wherein the laser beam generated by the laser generation unit is an ultraviolet laser beam extracted from a helium-cadmium (He-Cd) -based laser. The method of claim 1, wherein the laser separation unit, the first semi-transparent mirror for receiving a laser beam generated by the laser generating unit reflects one third of the incident laser beam and transmits two thirds; A second semi-transmissive mirror that reflects one half of the incident laser beam and receives one-half of the incident laser beam, and the laser beam transmitted from the second semi-transparent mirror And a total reflection mirror reflecting all of the incident laser beams. The laser image display apparatus of claim 3, further comprising an optical focus lens configured to focus the laser beam generated by the laser generator on the first semi-transmissive mirror. The image display unit of claim 1, wherein the image display unit comprises a shadow mask in which holes are regularly arranged so that the three beams are incident at unique angles, and a blue phosphor, a green phosphor, and three red phosphors correspond to each of the holes. Laser image display device comprising a fluorescent plate. The laser image display apparatus according to claim 1, wherein the phosphor of the pixel is a structure in which the phosphor is coated between two plates to prevent oxidation. A laser generator for generating a first laser beam, a second laser beam, and a third laser beam; An optical acoustic modulator (AOM) for modulating each of the first laser beam, the second laser beam, and the third laser beam according to a predetermined image signal; A laser deflector scanning three beams modulated by the photoacoustic modulator while moving horizontally and vertically in accordance with horizontal and vertical synchronization; And, And an image display unit for displaying an image by mapping the first laser beam, the second laser beam, and the third laser beam scanned by the laser deflector to the blue, green, and red phosphors of the pixel. Display. The laser beam of claim 7, wherein the first laser beam, the second laser beam, and the third laser beam generated by the laser generator are ultraviolet laser beams extracted from a helium-cadmium (He-Cd) -based laser. Laser image display device. 8. The image display apparatus of claim 7, wherein the image display unit comprises a shadow mask in which holes are regularly arranged so that the three beams are incident at a unique angle, and blue holes, green phosphors, and three red phosphors correspond to each of the holes. Laser image display device comprising a fluorescent plate. 8. The laser image display apparatus according to claim 7, wherein the phosphor of the pixel has a structure in which the phosphor is coated between two plates to prevent oxidation.

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