JPS5922351B2 - Luminous screen - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a light-emitting screen for color image display having a light amplification function.

Although several methods of optical amplifiers have been proposed in the past, none have yet been widely used due to their low amplification or monochromatic light display.

The present invention has been made in response to such conventional demands, and one embodiment thereof will be described in detail below.

FIG. 1 is a basic configuration diagram of the present invention. In the figure,
1 and 1' are transparent substrates such as glass, and 2 and 2' are transparent electrodes, on which indium oxide, tin oxide, etc. are provided by vapor deposition or the like. 3, 3', and 3'' are filter layers, which are provided on the inner surface of the substrate, and electrodes 2' are formed on the inner surface.

Electrode 2 is formed on the inner surface of substrate 1. The filter layers 3, 3', 3'' may be used as substrates without using the substrate 1'. Usually, the filter layers 3, 3 that transmit light of a desired wavelength of the incident light on the surface of the substrate 1' are used. ', 3'' are configured in a stripe shape, matrix shape, etc. For example, a dry plate coated with a color photosensitive material on the surface of a glass substrate is irradiated with light to form a desired pattern, developed and fixed to form a filter layer, and then indium oxide is placed on top of it as a transparent electrode 2'. Obtained by vacuum evaporation. Then, a photoconductor is provided on this transparent electrode 2'. For example, a photoconductive layer 4 made of cadmium sulfide, selenium sulfide, or the like with the addition of a small amount of copper is formed by vacuum evaporation, spray coating, or the like, and a light-shielding layer 5 and a reflective layer 6 are provided thereon. T
is a spacer for configuring a plasma space 8, and the plasma space 8 is arranged corresponding to the matrix or stripe of the filter layers 3, 3', 3'', and one plasma space becomes one light spot.Each plasma The surface of the transparent electrode 2 in the space is coated with a phosphor layer 9, 9', 9'' that emits light with a wavelength approximately equal to the wavelength of the transmitted light at the corresponding point of the filter layer 3, 3', 3''. output light 10, 10', 1
0'' is obtained. Note that 11 is the filter layer 3, 3',
The 3" spacer 12 is a high frequency power source applied between the electrodes 2, 2', and 13 is incident light. Next, its operation will be explained.

When the incident light 13 is split by the filter layers 3, 3', 3'' and imaged onto the photoconductive layer 4 through the transparent electrode 2',
Since the resistance value of the photoconductive layer 4 in this part decreases, the power supply 1
The electric field applied to the plasma space from 2 through the transparent electrodes 2 and 2' increases, and when it reaches a value sufficient to start a discharge, a discharge occurs in the plasma space, and electrons and charged particles are generated therefrom. The phosphor is excited by light or the like and emits light.

．． At this time, if the design is made so that the wavelength of the light incident on the photoconductive layer 4 and the wavelength of the light emitted from the phosphor are almost equal, a color matrix display can be performed. On the other hand, the change in the resistance value of the photoconductive layer 4 is not uniform in the thickness direction, and is greater toward the light incident side, and the thickness of the layer showing the change in resistance value is determined by the intensity of the incident light. FIG. 2 shows an equivalent circuit of one plasma space 8.

14 is the capacitance of the plasma space, 15 is a resistance indicating the discharge load, and a switch 16 starts the discharge and generates a light output 17.

18 is a light shielding layer 5, a reflective layer 6, a phosphor layer 9, 9', 9'5
19 represents the capacitance of the photoconductive layer 4, 20 represents the resistance whose value changes with the incident light 21, and 22 represents the resistance of the portion whose value does not change.

On the other hand, since the resistor 15 representing the discharge has negative voltage-current characteristics, an impedance is required in series to stabilize the discharge, and since the change in the resistor 20 is exponential, the optical output 17 has gradation. It is insufficient to have the resistance 22, and the presence of the resistor 22 is necessary.

Further, the reflective layer 6 and the light shielding layer 5 are arranged so that the output light 10, 10', 1
This is necessary in order to prevent the output light from irradiating the photoconductive layer 4 and causing the resistance value of the photoconductive layer to change due to the irradiated light so that light emission continues so that the output light can change in accordance with the constantly changing incident light 13. These must be made of a good insulator in order to display the output image clearly without the electrons flowing into the plasma space of the light emitting point leaking into other plasma spaces.

One of the most significant effects of the present invention is that it has become possible to drive a plasma matrix with high emission intensity and display bright color images without using a matrix drive circuit. This is due to the following reasons. The light-blocking layer must be provided with a reflective layer to make effective use of the full emitted power, in order to make the emission change in response to changes in the incident light, and they are good in order to establish image clarity. It must be composed of an insulating layer. For this reason, a device whose light emission is driven by a DC power source cannot be used. Therefore, a light emitting diode or the like with high emission intensity cannot be used. On the other hand, plasma is an example of a method that is driven by alternating current and has a high luminous intensity, but as mentioned earlier, the current-voltage equality of the discharge is negative, so each plasma luminous point making up the matrix has a step-by-step difference. It becomes difficult to provide tonality, resulting in an image display with strong contrast or no intermediate tones. In the present invention, the thickness of the photoconductive layer is determined, and in the equivalent circuit of the same layer, a part whose resistance value decreases exponentially due to incident light and a part in series with this part whose resistance value does not decrease and act as a high resistance element are constructed. In addition, the resistance value of the high-resistance portion, that is, the thickness of the portion where the resistance does not decrease, is controlled by the intensity of the incident light, and this is used as part of the series impedance for stabilizing the discharge of the discharge circuit, and the step of the output image is It enriches the tonality and has the effect of creating intermediate tones.

The second effect of the present invention is that when receiving light projected from a color TV picture tube or a color projector, each matrix has a spectral function and a function of emitting three primary color lights according to the spectral signal. Therefore, when used as a screen, it is possible to easily display light-amplified color images, with excellent contrast and brightness even in bright surroundings.
A tonal image is obtained. This effect is due to the effect of suppressing the power consumption of the light-emitting screen due to light amplification, and the excellent operability in which the main adjustments of the present invention are completed by superimposing the color matrix consisting of the three primary colors on the light-emitting point matrix during manufacturing. This is due to the effect of This is because the relative positional relationship between the spectroscopic function and the light emitting function is extremely close to each other, and both are extremely firmly fixed, so there will be no deviation in these in practical use, and the projected light can be projected onto the screen made of the present invention. Excellent color images can be obtained as long as imaging is performed.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of an embodiment of a luminescent screen according to the present invention, and FIG. 2 is an equivalent circuit diagram thereof. 2, 2'...Transparent electrode, 3, 3', 352...
... one layer of filter, 4... photoconductive layer, 5,
6... Insulator layer (light shielding layer and reflective layer), 8...
... Plasma space, 9,95,9'5... Fluorescent layer, 13... Incident light.

Claims (1)

[Claims] 1. A plurality of filter layers arranged in a stripe or matrix pattern that transmit light of a required wavelength of incident light, a photoconductive layer that is irradiated with light that has passed through each of the filter layers, and each of the filter layers. an insulating layer that blocks light generated in each of the plasma spaces, and each of the plasma spaces that emits light with a wavelength substantially equal to the wavelength of the light that has passed through each of the filter layers. A light-emitting screen comprising a phosphor layer provided therein, the photoconductive layer and insulator layer arranged in series with respect to the direction of incident light, and transparent electrodes arranged across a plasma space.