JPS6122518B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION This invention provides a method for forming stripes on a screen.
For example, a plurality of visible light phosphors that emit red, green, and blue visible light are arranged, and by exciting these visible light phosphors with invisible light, such as ultraviolet light, the screen itself emits light at a desired brightness and hue, and images are displayed. The purpose of this invention is to provide a new image display device that can display images.

Hereinafter, embodiments of an image display device according to the present invention will be described with reference to the drawings.

Fig. 1 shows an overview of the entire system of the device of this invention, where 1 is a light emitting source of invisible light, such as ultraviolet light;
get.

2 is a screen, and between this and the light emitting source 1, an ultraviolet beam deflector 3 and a half mirror 4 are arranged. This deflection device 3 is provided with, for example, two mirrors (not shown), and when one mirror rotates, the ultraviolet beam UV moves horizontally on the screen 2, and when the other mirror rotates, the ultraviolet beam UV The UV beam is made to move vertically on the screen 2, and the deflection device 3 causes the ultraviolet beam UV to scan horizontally on the screen 2 at a predetermined speed and sequentially move vertically at the horizontal scanning position. made to move in the direction.

The screen 2 includes three kinds of striped visible light phosphors R, G, and B that emit light in red, green, and blue hues when excited by the ultraviolet beam UV.
The striped ultraviolet light reflecting means 6 are arranged so that the longitudinal direction of each stripe coincides with the vertical direction on the screen 2.

In this case, the screen 2 is divided into a cue identification section 9 at one end in the horizontal direction and a light emitting display section 10 at the other end, and the three types of visible light phosphors R, G and B emit light. In the display unit 10, a fixed array pitch P is arranged in the horizontal direction of the screen 2.
The phosphors are arranged sequentially as B, R, G, B, R, G..., and a dark lane 8 with extremely low luminance is inserted between the visible light phosphors.

Further, the reflecting means 6 is provided for the purpose of obtaining an index signal for detecting the scanning position of the ultraviolet beam UV on the screen, and the arrangement pitch frequency is It has been different. In the example shown in the figure, the light-emitting display section 10 is arranged on every other dark lane 8, so the pitch is 2P, and the cue identification section 9 is arranged on every other dark lane 8.
They are arranged with an arrangement pitch P that is 1/2 that.

As this reflecting means 6, for example, as shown in FIG. 2, one in which a large number of cube mirrors 7 are arranged in one row is used. This cube mirror 7 is
As shown in the figure, the incident light is reflected and returned in the original direction.

When the ultraviolet beam UV from the light emitting source 1 scans the screen 2 configured in this way, the reflecting means 6
When the beam UV hits, as shown by solid line 11,
The reflected invisible ultraviolet light returns to its original direction, its optical path is bent by the half mirror 4, and the light enters a photomultiplier tube 12 as a photodetector and is detected. The detection output of this photomultiplier tube 12 is then sent to the drive circuit 1 as an index signal.
3. On the other hand, the drive circuit 13 is supplied with a color signal S _C and a luminance signal S _Y through a terminal 14 . This index signal is used as a color synchronization signal, and the index signal from the cue identifying section 9 and the index signal from the light emitting display section 10 are used to determine the color synchronization of each of the three primary color phosphors R, G, and B. Color synchronization is performed by predicting the position. That is, the drive circuit 13
The ultraviolet beam UV of light source 1 is
is optically modulated.

In this way, color synchronization is achieved and the three primary color phosphors R, G
and B are excited by the ultraviolet beam, causing each phosphor to emit light in each hue, thereby projecting a predetermined color image.

FIG. 3 shows another example of the device of this invention.

In this example, visible light phosphors R, G and B
A striped invisible light phosphor 15 is provided in the middle of the phosphors 15 and 15 mixed with these phosphors R, G, and B. In this case, the invisible light phosphor 15 is
For example, BaSiO ₅ :Pb (barium silicate which can be activated with lead) is used.

In this example as well, the three primary color phosphors R, G, and B are excited by the ultraviolet beam, but in this case, as shown in FIG. , once the phosphor 7 is excited, ultraviolet ray UV ₂ having a wider frequency bandwidth than the coherent ultraviolet beam UV is generated, and the phosphors R, G and B are each excited by this ultraviolet ray UV ₂ . and emit light in each hue.

Thus, in this example, rather than directly exciting the visible light phosphor with invisible light for scanning,
The invisible light phosphor is first excited with the invisible light for scanning, and the invisible light having a wider frequency band than the invisible light for scanning is obtained, and the visible light phosphor is excited by this. Coherent light with a single frequency can be used as invisible light for scanning, resulting in a sharp scanning spot, and the visible light phosphor can be excited with invisible light having a wide frequency band, increasing efficiency. is improved, and therefore the brightness is improved.

Below, it will be explained that excitation with invisible light having a predetermined frequency band is more efficient than excitation with invisible light of a single frequency.

That is, for example, ultraviolet light obtained from a heater-equipped discharge tube filled with mercury vapor has an emission line spectrum having a wavelength of 3650 Å and an intensity of 27,122 (relative value), as shown in FIG.

Next, when a phosphor with an excitation spectrum predominant in the ultraviolet region, such as BaSiO ₅ :Pb, is excited with coherent ultraviolet light having the spectrum shown in FIG. 5, the spectrum of ultraviolet light is as shown in FIG.
This results in an emission line spectrum of 3650 Å with a relatively wide spectrum ranging from 3250 Å to 3800 Å.

Next, FIGS. 7 and 8 show excitation spectrum graphs of excitation wavelength versus intensity of a red phosphor and a yellow phosphor using a fluorescent paint called Luminocolor (trade name). Note that FIGS. 7 and 8 show relative values of emission intensity when excited at a designated wavelength.

The total emission intensity of the phosphor in the case of coherent light and in the case of ultraviolet light having a frequency band excited in two stages is calculated as follows from FIGS. 5 to 8.

That is, the intensities shown in FIGS. 5 to 8 correspond to the wavelength λ
f ₁ (λ), f ₂ (λ), f ₃ as a function of
(λ), f ₄ (λ), when making a red phosphor emit light, in the case of coherent ultraviolet light/in the case of ultraviolet light with a frequency band =∫{f ₁ (λ) × f ₃ (λ)}dλ/∫{f ₂
(λ)×f ₃ (λ)}dλ = 1/11 When making a blue phosphor emit light, in the case of coherent ultraviolet light/in the case of ultraviolet light with a frequency band =∫{f ₁ (λ)×f ₄ ( λ)}dλ/∫{f ₂
(λ)×f ₄ (λ)}dλ = 1/12.

In other words, from the above, the emission intensity is higher when a visible light phosphor is excited by ultraviolet light with a relatively wide frequency band that is excited in two steps than when it is directly excited by a coherent ultraviolet beam. This results in a significant improvement in efficiency.

In fact, in an experiment, when we measured the luminance of red and yellow phosphors at a distance of 5 cm using a luminance meter, we found that the luminance during direct excitation/luminance during two-step excitation = 0.
5 ^ft-L /2.4 ^ft-L = 1/4.8, and it was confirmed that the efficiency was improved.

In this way, according to this example, a sharp scanning spot can be obtained and the brightness can be significantly improved.

As described above, according to the image display device of the present invention, a visible light phosphor is arranged on the screen, and an image is displayed by scanning the screen with invisible light, such as ultraviolet light. Therefore, compared to a cathode ray tube that displays images by scanning with an electron beam, there is no need to scan in a vacuum space, and there is also no need to apply high voltage to the screen.

Therefore, the image display device according to the present invention is suitable as a panel-type and thin image display device, and can also be used as a projection-type image display device even though a vacuum space is not required.

Furthermore, in this invention, by providing a light reflecting means as a means for generating an index signal, the reflected invisible light can be returned to the direction of the incident light, so that the space for obtaining the index signal is reduced. The effect is that it does not become so wide.

In addition, for example, when used as a light emitting source, something that optically oscillates only when light is detected,
It is also possible to construct the light emitting device so that the reflected light from the reflecting means is directly returned to the light emitting source, and to start oscillating when the light emitting source itself detects the reflected light from the reflecting means.

This is particularly effective when the reflecting means is provided on the phosphor.

Further, instead of providing a half mirror and returning the reflected light to the photodetector as in the example shown in the figure, the reflected light from the reflecting means may be directly returned to the photodetector.

Furthermore, the reflecting means is not limited to a cube mirror, but may be of any type as long as it returns the reflected light in the direction of the reflected light; for example, a plurality of spherical lenses arranged in a stripe pattern. You can also use

[Brief explanation of the drawing]

Fig. 1 is a diagram for explaining the outline of an example of the device of this invention, Fig. 2 is a diagram showing an example of its essential parts, and Fig. 3 is an example of the arrangement pattern on the screen of another example of the device of this invention. FIG. 4 is a diagram for explaining the main part thereof, and FIGS. 5 to 8 are diagrams for explaining the effect. R, G, and B are striped phosphors, 1 is a light emitting source, 2 is a screen, 6 is a reflecting means, 8 is a dark lane, 12 is a photomultiplier tube as a photodetector, and 13 is a drive circuit. .

Claims (1)

[Claims] 1 On the screen, a plurality of striped visible light phosphors that emit visible light of red, green, and blue, and whose longitudinal direction is the vertical direction of the screen, are sequentially arranged in the horizontal direction at a predetermined pitch, and the above-mentioned A dark lane with extremely low luminance is arranged between the visible light phosphors, and a stripe-shaped light reflecting means is provided on the dark lane to return the reflected light almost in the direction of the incident light. The image display device is configured such that the visible light phosphor is excited by being scanned by the visible light phosphor, and ultraviolet rays for indexing for color synchronization are obtained from the reflecting means.