JPH01108532A - Second higher harmonic display - Google Patents

Abstract

PURPOSE:To execute the operation at high speed by filling naphthylamine powder being a non-linear optical material for generating a second higher harmonic by the laser light incidence, between opposed substrates. CONSTITUTION:Naphthylamine powder 2 being a non-linear optical material for generating the second higher harmonic by a laser light incidence is filled between two pieces of opposed substrates 1, 1' in which at least one piece is transparent. Accordingly, when a laser is made incident on such a display, the second higher harmonic (SHG) is generated in the incident part, but this SHG is scattered by its own powder, and has no directivity, therefore, can be recognized as a display spot from every direction. In such a way, the device is simplified, and an operation of rewriting, etc. can be executed quickly.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a light-emitting display using a nonlinear optical material that generates second harmonics upon incidence of laser light.

Conventional technology CRT (cathode ray tube) and EL (electroluminescence) have been used as light-emitting displays, but the former requires high voltage, which makes the device complex and bulky as a whole. The latter also has the disadvantage of slow rewriting speed due to restrictions on the drive circuit.

On the other hand, it is also being considered to utilize nonlinear optical materials that generate second harmonics (SHG) as light sources for high-density recording or light sources for laser displays. But this kind of second
Conventionally, in order to use harmonics for recording, etc., phase matching between the incident electromagnetic wave and the generated second harmonic is essential, so nonlinear optical materials must be supplied in the form of single crystals, which are difficult to manufacture. Furthermore, it was necessary to perform fine adjustment of the incident angle and temperature control for the single crystal obtained in this way.

A first object of the present invention is to provide a light-emitting display that has a relatively simple device configuration and operates at high speed.

The second object of the present invention is to create a second harmonic wave that does not require phase matching, is easy to manufacture, and eliminates operations such as incident angle adjustment and temperature control by using a specific nonlinear optical material powder. It is to provide a display.

As shown in FIG. 1, the display of the present invention has two opposing substrates 1.1', at least one of which is transparent (in this example, both are transparent), and a second harmonic wave is produced by inputting a laser beam. It is filled with naphthylamine powder 2 as a nonlinear optical material that generates waves. Note that 3 is a spacer.

More specifically, the display of the present invention satisfies the average particle diameter r of the nonlinear optical material powder, the distance between the substrates or the thickness of the powder layer, and the beam radius of the laser beam under the conditions of r < L (D (m normal r = 1).
0-150 μs% L = 0.1-1 mm, D = 0.1-6
The nonlinear optical material powder is filled between two substrates so that the diameter of the optical fiber is 1 mm). Therefore, if a laser beam is incident on such a display, SHG will be generated at the incident area.
is generated, but this SHG is scattered by the powder itself,
Since it has no directionality, it can be recognized as a display spot from any direction. Note that the displayed color corresponds to the color of 172 wavelengths of the incident laser light. Of course, it is possible to display information on the entire display by scanning the laser beam all over the display. Furthermore, color display is also possible by preparing three types of lasers with wavelengths twice as long as the three primary colors of light.

The nonlinear optical material used as a light emitting source in the present invention is a powder of naphthylamines such as nitronaphthylamine, naphthylamine sulfonic acid, or a salt thereof. Table 1 shows the SHG strength of these naphthylamine powders and the color tone of the material powder itself. Note that the color tone of the powder serves as the background of the display.

Table 1 The laser light that generates SHG in nonlinear optical materials as described above must have a wavelength in the visible range when converted to a double wave, so the laser light shown in Table 2 below must be in the visible range. is used.

Table 2 Since the efficiency of SHG is proportional to the intensity of the incident laser, in the present invention we use Nd(I[) laser, that is, Nd'':
A YAG or Nd'' glass laser is suitable.

The present invention will be explained below by way of examples.

Example 1 As a nonlinear optical material, 4-nitro-1-naphthylamine powder was placed between two opposing white glass plates with a thickness of about 2 mm.
The mixture was filled without any gaps by ultrasonic vibration through a mm-thick spacer to produce a second harmonic display with a pale yellow-orange surface.

Next, adjust the beam diameter to about 1m from one side of this display.
Nd:YAG laser beam reduced to m (average output 5W)
When it was incident, a green SHG spot was confirmed. When this laser beam was scanned on a display, a green scanned image was displayed.

Example 2 2-naphthylamine-5-sulfonic acid Na powder was used as the nonlinear optical material, and the spacer thickness was 0.5 mm.
A second harmonic display with a white surface was produced in the same manner as in Example 1, except for the following.

When laser light was applied to this display and scanned in the same manner as in Example 1, similar effects were confirmed.

Effects As described above, the display of the present invention uses a nonlinear optical material that generates SHG when laser light is incident on it.
The device has been simplified, and operations such as rewriting have become faster. In addition, since this nonlinear optical material can be used in a powder state, it does not require phase matching unlike single crystals, and has the advantage of being easy to manufacture and eliminating tasks such as incident angle adjustment and temperature control. There is also.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an explanatory diagram of a second harmonic display according to the present invention. 11′...Substrate 2...Nonlinear optical material powder 3
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Claims (1)

[Claims] 1. Between two opposing substrates, at least one of which is transparent,
A second harmonic display characterized by being filled with naphthylamine powder as a nonlinear optical material that generates a second harmonic upon incidence of laser light.