JPS59177595A - Display unit - 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 Field of the Invention The present invention relates to a display device, and particularly to a display device that forms a visible image on a screen by scanning the screen using an infrared beam as an MS source. I'm going to do it.

(Contrary to the prior art' M7) Normally, such a beam-scanning display device scans a white screen with a visible light laser and modulates the intensity of the nuclear laser beam by 1 dI after the scanning, thereby saving the image display. Alternatively, a structure has been used in which a short-wavelength laser in the ultraviolet region is used instead of the visible light laser as the heam generating means, and a common phosphor screen that converts short-wavelength light into visible light is used as the screen. . However, when using the above-mentioned visible light laser, the beam light is coherent light (I\(l).

Since the light is coherent (coherent light with a uniform phase), interference occurs, causing a characteristic flicker on both sides, which is very unsightly. - When using a laser with a power i>wavelength, if the beam light is outside the visible range, only the secondary radiation will appear on the screen, so the above flicker will disappear, but considering a laser with the same output, as the wavelength becomes shorter, the device 6
cannot be avoided from becoming large and expensive.

<Purpose and Features> In view of the above, the object of the present invention is to combine infrared rays outside the visible band to the long wavelength side as a modulated light beam, and combine it with a special phosphor that converts the infrared rays to short wavelengths. Therefore, the above-mentioned flickering is also caused by the Hj value of the device.A) The feature of the present invention is to provide a display device in which the flicker is eliminated. an infrared beam whose output can be modulated accordingly;
When a visible image is drawn by scanning the phosphor screen with a modulated infrared beam, more specifically, a semiconductor laser is used as the infrared beam generating means.

<Embodiment> The figure is an explanatory diagram of an example of the present invention, and shows the configuration of the display device ff'W. In the figure, 2 is a semiconductor laser, 1 is a semiconductor laser, Modulation drive drive%, 1
1 circuit, 3 is a Collinaut lens, 4.4' is an imaging lens, 5 is a circuit mirror for main scanning, 6 is a carbano mirror for sub-scanning, and 7 is an f circuit for correcting scanning distortion on the screen. Lenses 8 are not shown because they are used for infrared light, but they are sent to rotating mirror 5.
Due to the main j-to-scanning at a predetermined speed, 1 drive error occurs, and the scanning of the rotating mirror 5 is the same as 1↓JI. While scanning the screen 8-H with the beam of J, the driving circuit 1 scans the screen 8-H in synchronization with the screen scanning by the first main and sub-scanning.
1 for depicting a curved image on the screen, 8-7, by modulating the semiconductor laser in a manner according to the signal f=j;
11. Control means and drive means for auxiliary scanning shall be provided. When considering a device having such a configuration, the key to realizing such a display device is what to use as a light source and whether a phosphor satisfying the above characteristics can be realized. Examples of the above-mentioned special phosphors include compounds doped with rare earth elements, such as YF doped with erbium (Er); Er YOC4; Er+ Ba Y2
FB: A compound called 'F:r emits green light when irradiated with infrared light, and J, aJ'i'3; It is known that such phosphors emit mixed light, and if such phosphors are formed as a layer on the screen substrate, the desired screen can be obtained.

In order to produce an imperial edict screen, the inventor dissolved acrylic J, T7J fat, (acrylic 4gj fat content 7; (ko 0 ears i country percentage) liquid body 1 Oki Hayabusa part and the above into it. The above YF,...: Er fine powder 2M1〒) was milled in a ball mill for about 24 rounds. ) 7; Create a uniformly divided mixture with fll L, and apply it to a flat glass substrate and coat it with a bar coater. The film was coated on a sheet of paper, allowed to air dry for about 24 hours, and then finished and dried in a constant temperature bath at 80° C. for 1 hour to create an A4 size screen. On the other hand, as a laser with high light intensity, a semiconductor laser with an emission wavelength of 9sooX and a continuous output of 10mW has been produced, and is well known as a laser beam with a main and sub-scanning system configured as shown in the figure. Dark 1 of the ``Ryo-I elephant pattern'' taken from the Ganta Sensor
A beam obtained by directly modifying the above semiconductor laser with a modified T'JFJ number corresponding to
Due to interference (a flickering-free image is obtained using the 4 formulas), in actual experiments, the conversion efficiency of infrared light to visible light is as low as about 1 factor for the old-fashioned phosphor YF, q: 1 minute. Therefore, the screen could only be scanned at a few frames per second, but by increasing the output of semiconductors and lasers, and by using YOCI;
We now have the prospect of obtaining a screen scanning repetition rate that is sufficient to render moving images. When using infrared rays, a semiconductor laser can be used as a light source, and the intensity of the output beam of the semiconductor laser can be directly modulated using a multi-gradation video signal. Semiconductor lasers can be used as modulators at present, where it is difficult to make semiconductor lasers emit light stably and with a long life at wavelengths shorter than the infrared band. This in itself can be said to be a major feature from an industrial perspective. Although the above screen was used on the secondary reflection side, it can also be seen from the back! It was found that ii images can be seen and it can also be used as a transmissive screen.

<Effects> As stated above, according to the present invention, by combining a semiconductor laser that emits light in the infrared band and a special phosphor screen that converts infrared light into visible light, flickering due to interference can be eliminated. , a projection type display unit capable of [1] halftone ttb 'l-J' can be realized at an extremely low cost.
Moreover, it has the characteristic effect of being able to be made smaller.

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[Brief explanation of the drawing]

The figure is an explanatory diagram of one implementation column of the present invention, in which 1 is a drive circuit, 2
is a semiconductor laser, 5 is a rotating mirror, 6 is a galvanometer mirror 18
indicates a screen. r-□ Agent Patent Attorney Hiroshi Matsuoka, Department. 11'1・

Claims (1)

[Claims] ]) A pure infrared beam generating means whose output can be modulated according to a signal, a phosphor screen that converts infrared rays into visible light, and a scanning means that scans the infrared beam, A display device characterized in that a visible image is drawn by scanning an infrared light beam on a light screen. 2) A display device according to Item 1, Paragraph 1 (&) of Patent G, characterized in that the infrared beam generating means is a semiconductor laser.