JPH04149518A - Electron beam write type transmission spatial optical modulating tube - Google Patents

Abstract

PURPOSE:To display an image and a pattern which are bright, high in contrast, and superior in spatial uniformity without using a polarizing prism nor a polarizing plate which has the same function as the former by utilizing light scattering characteristics obtained by applying a voltage to a liquid crystal compound body. CONSTITUTION:The liquid crystal compound body 21 is constituted by confining liquid crystal 23 to a transparent resin matrix 24 which is nearly equal in refrac tive index to nematic liquid crystal 23, and a target 9 is formed by interposing the liquid crystal compound body 21 so as to stick it to a transparent dielectric layer 22 and a transparent electrode 20. Then the spatial optical modulating tube is constituted by using this target 9, an electron gun 1, a vacuum container 11 which incorporates a collector 10 for controlling electrostatic charges on the surface of the target 9, and an electron beam deflection system which deflects an electron beam 15.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an electron beam writing type spatial light modulation tube, and more specifically, to a method for inputting image information and data information into a spatial light modulation tube using an electron beam. , relates to an electron beam writing type transmission type spatial light modulation tube having a function of displaying this information two-dimensionally using display light.

[Summary of the Invention 1 The present invention is an electron beam writing type transmission type spatial light that has the function of manually writing image information or data information to a target using an electron beam, and displaying this information two-dimensionally using display light. Regarding the modulation tube, especially between the transparent dielectric layer and the transparent electrode,
Nematic liquid crystal.

A structure in which cholesteric liquid crystal or smectic liquid crystal is confined in a transparent resin matrix having a refractive index equivalent to either the ordinary refractive index, the extraordinary refractive index, or the refractive index when the liquid crystal is randomly oriented. Alternatively, a target in which a liquid crystal composite having a structure in which the resin matrix is dispersed and confined in the liquid crystal is inserted in close contact with the transparent dielectric layer and the transparent electrode, and electron generation.

An electron gun consists of a cathode and one or more grids that form, accelerate, and focus an electron beam and control the electron beam intensity according to an input signal, and a secondary electron trap that controls the charge on the target surface. Since the electron beam writing transmissive spatial light modulation tube is constructed using a vacuum vessel containing a collector and an electron beam deflection system that deflects the electron beam, ■ a polarizing plate is not required. A bright display image can be obtained; (1) the spatial appearance of the displayed image is excellent; (2) the response is fast (2) the contrast is high (2) the display of analog images is facilitated.

[Prior Art] Devices disclosed in the following documents are known as electron beam writing spatial light modulation tubes.

(1) Reference 1 (G, Marie: Ferroel
etrics Vol, 10° (1976) P, 9
~P, 14) includes a vacuum container 11 as shown in FIG.
Inside the CaFz holder 34. Transparent electrode 20゜KD2
P0433, a target 79 to which a dielectric mirror 22' is successively adhered, and a Vertier element 35. An electron beam writing type spatial light modulation tube is shown in which a cathode 2°, a main grid 10", and a subgrid 1O" are enclosed.
6 is a light source, 28 is a lens, 38 is a polarizing prism, 16 is incident light, 17 is display light, and 15 is an electron beam.

In the above configuration, the constant current electron beam emitted from the cathode collides with the dielectric mirror and forms a charge pattern on the surface of the dielectric mirror in response to a signal applied between the main grid and the transparent electrode.

This charge pattern is converted into a spatial change in refractive index by the electro-optic effect of the KD and PO4 crystals.

On the other hand, the incident light 16 emitted from the light source 26 is polarized by the polarizing beam splitter 38 and passes through the lens 28.
CaF in the vacuum container 11, holder 34. transparent electrode 20
, KD, P04 crystal, is reflected by the dielectric mirror 22°, follows the above-mentioned optical path in reverse, passes through the polarizing beam splitter 38, and is projected onto a screen (not shown) as display light.

(2) Literature 2 (K, 5 hinoda and Y, 5
uziki: Proc.

5PIE (1986) P. 613-P, 619), as shown in FIG.
Thin film 40. Dielectric mirror 22', LiNb0. Crystal 41. a target 89 to which transparent electrodes 20 are successively adhered;
Transparent electrode 20. LiNb0s41 and a phase compensation plate 42 to which the transparent electrode 20 is adhered in order. Cathode 2. grid 42
．． 43.44.45.46.47 and mesh electrodes (
An electron beam written spatial light modulation tube encapsulating a collector (collector) 48 is shown. In the figure, 18 is a beam splitter, 149 is a polarizing plate, 28 is a lens, 26 is a light source, 30 is a screen, 16 is incident light, 17 is display light,
and 15 is an electron beam.

In the above configuration, the constant current electron beam 15 emitted from the cathode 2 passes through the grids 42 to 47 and the mesh electrode 48 and collides with the MgO thin film 40.

By applying an electrical signal to the grid 42 and controlling the electron beam current, a charge pattern is formed on the surface of the MgO thin film. This charge pattern is similar to that of LiNb0. The crystal's electro-optic effect translates into a spatial change in refractive index.

On the other hand, the incident light 16 from the light source 26 is transmitted to the lens 28. The light passes through the polarizing plate 49 and the beam splitter 18, passes through the phase compensating plate 42 in the vacuum container 11 and the target 89, is reflected by the dielectric mirror 22°, and follows the opposite optical path to the beam splitter 18, the lens 28, and so on. The image or pattern is projected onto the screen 30 through a polarizing plate 49.

(3) Literature 3 (D, A,) laven: IEEE
Transaction Electron
Devices Vol, ED-30, (1983) P
, 498-P, 492), a target 99 and a writing electron gun 1 are placed in a vacuum container 11 as shown in FIG.
26 is a light source, 28 is a lens, 49 is a polarizing plate,
15'' is an electron beam for writing, 15'' is an electron beam for erasing, 16 is incident light, and 17 is display light.Target 9
9, as shown in FIG. 10, the face plate 11' of the vacuum container, the transparent electrode 20. Twisted nematic liquid crystal52. Spacer 53. It is composed of a dielectric thin plate 54. In addition, in the figure, 55 is a secondary electron collecting electrode (collector). Furthermore, although not shown in the figure, in order to align the twisted nematic liquid crystal, transparent electrodes 2
An alignment layer is required between the thin dielectric plate 54 and the liquid crystal 52.

In the above configuration, if the intensity of the electron beam emitted from the write electron gun is controlled by applying an electric signal to the grid (5) not shown, a charge pattern corresponding to the input signal can be formed on the surface of the dielectric thin plate 54. I can do it. At this time, the liquid crystal molecules in the target 99 are arranged according to this charge pattern, and the spatially uniform incident light emitted from the light source 26 passes through the polarizing plate 49, the target 99, and the polarizing plate 49, and the light intensity changes according to the human input signal. converted to an image.

(4) Reference 4 (T, T, True: SID '8
7 International Symposium
(1987) P, 68-P, 71), as shown in FIG. 11, a target 109 of a glass disk whose one side is electrically conductive is placed in a vacuum container 11. It contains 57 transparent oil masks, 58 masks, and 1 electron gun. In the figure, 26 is a light source, 25 is a total reflection mirror, 59 is a dichroic filter, Z8 is a lens, 16 is incident light, and 1
7 is display light.

In the above configuration, the white incident light 16 from the light source is separated into blue and red light beams by the dichroic filter 59, as shown in FIG. 11(a). input mask 58
In the central and peripheral parts of the output mask 60, the directions of the slits are perpendicular to each other as shown in FIGS. It constitutes a system. target 109
rotates slowly while immersed in transparent oil 57 in an oil sump 57°, forming a smooth oil film layer on the glass surface of the target. If the electron beam 15 does not enter this oil film layer,
The surface of the oil film layer is smooth, and the blue and red light beams are blocked by the output mask and do not reach the screen.

On the other hand, when the electron beam collides with the oil film layer, the surface of the oil film becomes electrically charged, and the oil film layer is distorted by electrostatic force. At this time, the light beam is diffracted by the oil film layer, passes through the gap in the output mask, and reaches the screen.

[Problem to be Solved by the Invention 1] However, the above-mentioned conventional electron beam writing type spatial light modulation tube has the following problems to be solved.

(I) In the spatial light modulation tube of Document 1 shown in FIG. 7 in Section (1) described as the prior art, or in the spatial light modulation tube of Document 2 shown in FIG. 8 in Section (2), KD, PO, Crystal 33 or LiNb0. Since the electro-optic effect of the crystal 41 is utilized, (1) a polarizing beam splitter 38 or a polarizing plate 49 is required; therefore, if the incident light 16 is unpolarized light, the propagation loss of the light will be 50% or more.

Since it is necessary to make the thickness of KD2PO crystal 33 or K1Nb0-crystal 41 uniform, advanced crystal processing technology is required and it becomes expensive.

If the spectral width of the incident light 16 is wide, the contrast of the output image will be reduced.

It is necessary that the incident light 16 be highly parallel. For this purpose,
It is necessary to make the light emitting portion of the light source 26 point-like, and this also reduces the brightness of the display light.

Making the KD2P04 crystal 33 or the LiNbO5 crystal 34 thinner (resolution improves), but there is a limit (currently about 100 μm) to making the bulk crystal thinner by polishing, which makes it difficult to achieve high resolution.

Obtaining a large-area KD2PO-crystal 33 or LJbOm crystal 41 is technically and economically difficult.

Due to the drawbacks (1) and (2) above, it is difficult to display highly accurate images and patterns.

■ The driving voltage is large.

There are drawbacks such as. Furthermore, as described as conventional technology (1)
In the spatial light modulation tube of Document 1 shown in FIG. 7 of Section 1, it is necessary to cool the KD, PO, and crystal 33 to about 50° C. using the Bertier element 35, which makes the device configuration complicated.

There is also the problem.

(U) In the spatial light modulation tube of Document 3 shown in FIGS. 9 and 10 in Section 3 described as the prior art, the twisted nematic liquid crystal 52 is used, so the polarizing plate 49 is required. Optical propagation loss becomes 50% or more.

■ Slow response.

■ Requires an alignment layer to orient liquid crystal molecules in advance, which complicates the production process.

There are drawbacks such as. Therefore, the spatial light modulation tube of Document 3 is
Not suitable for bright video display.

(11?) In the spatial light modulation tube of Document 4 shown in Fig. 11 in section (4) mentioned as the prior art, transparent oil 57 is used, so ■ The collision of the electron beam with the oil film layer causes oil vapor to be generated. occurs and deteriorates the cathode filament. It also reduces the degree of vacuum in the vacuum container.

■ Since the oil is heated before use, a warm-up time of several tens of minutes is required.

■ Since the diffracted light in the oil film layer is used as display light, a large schlieren optical system is required to minimize the loss of display light.

■ It is extremely expensive as it requires a highly accurate and large schlieren optical system.

There are drawbacks such as. Therefore, the spatial light modulation tube of Document 4 cannot be used as a compact and inexpensive image display device.

There are drawbacks such as:

Therefore, the purpose of the present invention is to solve the various problems mentioned above, to be able to display high-quality and bright images and data patterns at high speed, and to display high-definition moving images on a large screen. The object of the present invention is to provide a compact electron beam writing type spatial light modulation tube suitable for image processing.

[Means for Solving the Problems 1] In order to achieve the above object, the present invention provides a nematic liquid crystal layer between a transparent dielectric layer and a transparent electrode.

A cholesteric liquid crystal or a smectic liquid crystal is dispersed in a transparent resin matrix having a refractive index equivalent to either the ordinary refractive index, the extraordinary refractive index, or the refractive index when the liquid crystal is randomly oriented. A target in which a liquid crystal composite having a confined structure or a structure in which a resin matrix is dispersed and confined in the liquid crystal is inserted in close contact with the transparent dielectric layer and the transparent electrode, and electron generation, 1! One or more electron guns each consisting of a cathode and one or more grids that form, accelerate, and focus a child beam and control the electron beam intensity according to an input signal, and one or more electron guns that control the charge on the surface of the transparent dielectric layer. It is characterized by comprising a vacuum vessel containing a secondary electron collection electrode (collector) for deflecting the electron beam, and a spatial light modulation tube using an electron beam deflection system for deflecting the electron beam.

Furthermore, the first embodiment of the present invention is characterized by having a target to which a face plate of a vacuum container, a transparent electrode, a liquid crystal composite, and a transparent dielectric layer are successively adhered.

Further, in the second embodiment of the present invention, the secondary electron emission ratio δ (the number of electrons incident on the target surface is n l
+If the number of emitted electrons is 02, then 6=na/n+)
It is characterized by the fact that a large material (for example, MgO thin film) is attached.

Furthermore, a third aspect of the present invention is characterized in that the optical system has an aperture that passes non-scattered light and blocks scattered light, or an aperture that has the opposite effect.

Furthermore, a fourth aspect of the present invention is characterized in that the target is simultaneously scanned with a fixed time difference between the erasing electron beam and the writing electron beam.

1 Effect 1 Since the present invention has the above-described configuration, it is possible to display high-quality and bright images and data patterns at high speed, and is suitable for high-definition video display. screen becomes possible.

(1) In other words, the spatial light modulation tube of the present invention utilizes the light scattering properties caused by applying voltage to the liquid crystal composite, so it can display images without using a polarizing prism or a polarizing plate with an equivalent function. be able to. Therefore, the present invention is capable of displaying bright, high-contrast images and patterns with excellent spatial appearance, and also has the following points: (1) large light propagation loss, which is characteristic of the conventional spatial light modulation tube described in item (I) above; , ■ Requires advanced crystal processing technology, ■ Decreased contrast, ■ Requires high parallel characteristics for display light, ■ Large drive voltage, etc. The characteristics of the conventional spatial light modulation tube described are: ■ large optical propagation loss, ■
Problems such as slow response, ■ Requires a liquid crystal alignment layer, and problems specific to the conventional spatial light modulation tube described in the above (fff), ■ device deterioration due to oil vapor, and ■ startup problems. It does not have the problems of requiring a long time, (1) requiring a large schlieren optical system, and (2) being extremely expensive.

(2) Furthermore, whereas conventional spatial light modulation tubes using liquid crystals require strict control of the thickness of the liquid crystal layer (for example, the thickness error is less than 1/10 of the incident wavelength), the present invention In this spatial light modulation tube, variations in the thickness of the liquid crystal composite are allowed up to several times the incident wavelength, so it can be made much larger than conventional spatial light modulation tubes, and the device manufacturing is easier. be.

(3) In addition, the light transmittance vs. applied voltage characteristic of the liquid crystal composite constituting the present invention has a smaller γ characteristic (change in light transmittance with respect to minute change in applied voltage) than that of twisted nematic liquid crystal. Therefore, it is possible to display analog images and is suitable for analog display.

(4) Furthermore, the response speed (several milliseconds to tens of milliseconds) of the liquid crystal composite constituting the present invention is faster than that of twisted nematic liquid crystal. Therefore, the spatial light modulation tube of the present invention has a faster response speed than the conventional spatial light modulation tube described in item (II) above, and is suitable for displaying moving images.

(5) Also, in the present invention, by using a plurality of electron guns and simultaneously scanning the target with a certain time difference between the erasing electron beam and the writing electron beam,
It is possible to display bright images with little shading.

It also has other advantages.

[Example] Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

FIG. 1 schematically shows the structure of an embodiment of an electron beam writing type spatial light modulation tube according to the present invention. In the same figure, 1
is an electron gun consisting of a cathode 2 and grids 3゜4.5.6 and 7. Together with an external coil 8, the electron beam generated by the cathode 2 is used to accelerate, focus, and deflect the electron beam. It also has the function of controlling the electron beam intensity in accordance with an input signal and applying electrons to the surface of the target 9 to form a two-dimensional charge pattern on the target surface or to erase the charge pattern. cathode 2
．． The grids 3 and 4 form thermoelectrons emitted in random directions from the cathode surface into a narrow beam, and control the electron beam intensity by changing the potential difference between the constituent electrodes. Sections of grids 5, 6 and 7 serve to focus the electron beam to a small spot on the target surface.

The configuration of the electron gun shown in Figure 1 is optically a unipotential type that corresponds to a thin lens, but it is also a unipotential type that corresponds to a thick lens and a focusing coil (not shown). It is also possible to make the beam spot diameter on the target surface smaller. In Figure 1, lO is a secondary electron collection electrode (collector), 11 is a vacuum vessel with a transparent face plate 11', 12 is a voltage lead wire applied to the transparent electrode, and 13 is a voltage lead wire applied to the collector. Lead wires 14 are input signal lead wires, 15 is an electron beam, 16 is incident light, 17 is display light, and 27 is an ultraviolet cut filter for protecting the liquid crystal composite from ultraviolet light. Note that v5 is the potential of the transparent electrode, ■. is the potential of the collector.

FIG. 2 shows a detailed configuration example of the target 9 of the embodiment shown in FIG. As shown in the figure, Targetera l-9 of this embodiment has a transparent substrate 19. Transparent electrode 20, liquid crystal composite 2
1. It is an element in which transparent dielectric layers 22 are successively adhered to each other, and a lead wire 12 is connected to the transparent electrode 20.

The liquid crystal composite 21 used in the present invention includes a nematic liquid crystal, a cholesteric liquid crystal, or a smectic liquid crystal 23, and either the ordinary refractive index, the extraordinary refractive index, or the refractive index when the liquid crystal is randomly oriented. It consists of a transparent resin matrix 24 having the same refractive index, and has a configuration in which the liquid crystal is dispersed and confined in the resin matrix, or a configuration in which the resin matrix is dispersed and confined in the liquid crystal. That is, in the liquid crystal composite 21 of the present invention, for example, as shown in FIG. 2, the liquid crystal is formed in a resin matrix 24 in a spherical or non-spherical shape (the length thereof is from several hundred nanometers to about 20 micrometers).
or liquid crystal is confined in a resin matrix in a so-called microcapsule shape (not shown), or liquid crystal has a mesh-like resin matrix (not shown).

In the liquid crystal composite body 21 having such a configuration, when the ordinary refractive index or the extraordinary refractive index of the liquid crystal 23 and the refractive index of the resin matrix 24 almost match, a state in which no electric field is applied to the liquid crystal composite body 21 ( That is, if the potential of the surface of the transparent dielectric layer 22 of the target 9 is V, then V,=
In the state where the liquid crystal 23 and the resin matrix 24 have different refractive indexes, the light is scattered in a scattering state. In the state of V°), since the refractive index of the liquid crystal 23 and the resin matrix 24 match, a light transmitting state is achieved. Furthermore, when the refractive index when the liquid crystal 23 is randomly oriented and the refractive index of the resin matrix 24 are almost the same, the refractive index of the liquid crystal 23 and the resin matrix 24 is the same when no electric field is applied to the liquid crystal composite 21. Since they match, it becomes a light-transmitting state. On the other hand, when an electric field is applied to the liquid crystal composite 21, the refractive indexes of both 2' and 3.24 differ, and a light-scattering state occurs.

In the present invention, both types of liquid crystal composites can be used, but the former type in which the ordinary refractive index or extraordinary refractive index of the liquid crystal 23 and the refractive index of the resin matrix 24 substantially match is more preferable. In particular, a type in which the ordinary refractive index of the liquid crystal 23 and the refractive index of the resin matrix 24 are almost the same is optimal in terms of performance.

The method of manufacturing a target containing a liquid crystal composite shown in FIG. 2 is simpler than conventional methods of manufacturing liquid crystal cells. For example, the target 9 can be formed by inserting the liquid crystal composite 21 between the transparent substrate 19 to which the transparent electrode 20 is attached and the transparent dielectric layer 22, and performing ultraviolet irradiation and heating. This method does not require an alignment layer for uniformly aligning liquid crystal molecules, and a target with a large area can be easily formed.

Next, the operation of the electron beam writing type spatial light modulation tube having the liquid crystal composite body 21 in which the ordinary refractive index of the liquid crystal 23 and the refractive index of the resin matrix 24 are almost the same will be explained. In addition,
In the spatial light modulation tube of the present invention, either scattered light or non-scattered light can be used as display light, but hereinafter, a case where non-scattered light is used as display light will be described as an example.

First, basic operations related to controlling the charge on the surface of the transparent dielectric layer 22 of the target 9 will be described.

The electric field applied to the liquid crystal composite 21 includes the potential (V, ) of the transparent electrode 20, the potential (V, ) of the collector, and the electron beam 1.
5 and the secondary electron emission characteristics of the transparent dielectric layer 22. The secondary electron emission characteristic is the secondary electron emission ratio δ
This is the acceleration voltage dependence characteristic of primary electrons (electrons that collide with the transparent dielectric layer), and is expressed, for example, as shown in FIG. In the figure, the acceleration voltage corresponding to δ=1 is set to the first crossing voltage (
vl) and the second cross voltage (v2), ■When an electron with energy corresponding to an accelerating voltage of 1 or less or 72 or more collides with the transparent dielectric layer, δ becomes 1,
The surface of the transparent dielectric layer is negatively charged.

On the other hand, when electrons having energy corresponding to an accelerating voltage greater than vl and smaller than v2 collide with the transparent dielectric layer, δ>l, and the surface of the transparent dielectric layer is positively charged. Therefore, by controlling the above-mentioned V, V, the potential of the electron gun, etc., the polarity and δ of the charges charged on the surface of the transparent dielectric layer can be determined. At this time, if the current value of the electron beam is also controlled by an electric signal input to the lead 1114, a charge pattern can be formed on the surface of the transparent dielectric layer.

Next, the operation of the electron beam writing type spatial light modulation tube of the present invention will be specifically described. The method of operating the spatial light modulation tube can be roughly divided into two methods described below.

(A) V. is fixed and write mode (mode where a charge pattern is formed on the surface of the transparent dielectric layer according to the input signal)
, and a method of controlling the magnitude of vb corresponding to the erase mode (a mode in which the surface of the transparent dielectric layer is spatially uniformly charged or uncharged).

(s) A method of fixing V and controlling vc in response to write mode and erase mode.

Method (A) above includes the following four basic methods in which erasing and writing are a series of operations.

(a) Method of forming a positive charge image on the surface of the transparent dielectric layer (b) Method of forming a positive charge reversal image on the surface of the transparent dielectric layer (c) Method of forming a negative charge image on the surface of the transparent dielectric layer ( d) Method of forming a negative charge reversal image on the surface of a transparent dielectric layer In the methods (a) to (d) above, the collector potential v0 is set to the second cross potential (2) in FIG.

Next, these four types of methods will be explained in detail.

(a) Method of forming a positive charge image on the surface of a transparent dielectric layer (a-1) Erasing mode Potential of transparent electrode 20 ■. Set to v2 (■.=■2
) and the potential V on the surface of the transparent dielectric layer 22 is the value of v2 plus the potential due to positive charges generated by writing.

That is, since ■1≧■2 and δ≦1, the surface of the transparent dielectric layer 22 is irradiated with the electron beam 15 to add a negative charge, and δ=1(v,=Vt
). At this time, the charge on the surface of the transparent dielectric layer is 0, and no electric field is applied to the liquid crystal composite 21, so that the incident light is scattered by the liquid crystal composite 21. Therefore, the displayed image shows a spatially uniform dark state.

(a-2) Write mode The potential of the transparent electrode 20 is set to V, <V<L.

At this time, the potential v8 on the surface of the transparent dielectric layer 22 is also V +
<Vゎ〈v2, so δ〉1. Therefore, when the electron beam 15 impinges on the surface of the transparent dielectric layer, the mirror surface becomes positively charged and a positively charged image is formed. At this time, since an electric field is formed in the liquid crystal composite 21 from the surface of the transparent dielectric layer 22 toward the transparent electrode 20, the incident light is transmitted through the liquid crystal composite 21 according to the electric field strength. Therefore, the displayed image is in a bright state (the part written by the electron beam is bright)
become.

(b) Method of forming a positive charge inversion image on the surface of a transparent dielectric layer (b-1) Erasing mode The potential Vb of the transparent electrode 20 is set to V, <Ve<V.

At this time, L<Vg≦v2 holds true for both the potential of the surface of the transparent dielectric layer 22 written with the electron beam and the potential of the surface of the transparent dielectric layer 22 not written with the electron beam. Therefore, δ≧1, and the surface of the transparent dielectric layer is positively charged by electron beam irradiation. Secondary electrons emitted from the surface of the transparent dielectric layer are collected by a collector at a higher potential than the surface of the transparent dielectric layer. When the surface potential of the transparent dielectric layer reaches 2, δ=1, and the surface of the transparent dielectric layer becomes uniformly positively charged. At this time, an electric field is formed in the liquid crystal composite 21 from the transparent dielectric layer 22 toward the transparent electrode 20, so that the incident light is transmitted through the liquid crystal composite without being scattered. Therefore, the displayed image is uniformly in a bright state.

(b-2) Write mode The potential V of the transparent electrode 20 is set to L<v. At this time, the surface potential of the transparent dielectric layer 22 also becomes V−>Va,
δ kl. Therefore, a negative charge is added to the surface of the transparent dielectric layer 22 according to the current value of the writing electron beam 15,
This neutralizes the positive charges that were previously formed in a negative manner, and an inverted image of the positive charges is formed. When light enters the liquid crystal composite 21, the light is scattered in accordance with the amount of attenuation of the positive charge, and the displayed image becomes dark (the part written by the electron beam is dark).

(c) Method of forming a negative charge image on the surface of the transparent dielectric layer (c-1,) Erasing mode potential of transparent electrode 20 ■. is set to v2 (vb= v
i) and the potential V of the surface of the transparent dielectric layer 22 are the sum of (2) and the potential due to negative charges generated by writing. That is, ■1≦vt and δ≧1, so the surface of the transparent dielectric layer 22 is irradiated with the electron beam 15 to add a positive charge, so that δ=I (V
-=Va). At this time, the charge on the surface of the transparent dielectric layer is 0, and no electric field is applied to the liquid crystal composite 21, so that the incident light is scattered by the liquid crystal composite 21.

Therefore, the displayed image shows a spatially uniform dark state.

(c-2) Write mode The potential of the transparent electrode 20 is set to v,>vi. At this time, the stated potential of the transparent dielectric layer 22 becomes V->Vg, and becomes δ<1. Therefore, a negative charge image is formed on the surface of the transparent dielectric layer depending on the current value of the writing electron beam. That is, since an electric field is formed from the transparent electrode toward the transparent dielectric layer, the light incident on the liquid crystal composite 21 is transmitted in accordance with the amount of negative charge, and the displayed image is in a bright state (the electron beam writes The darkened areas become brighter).

(d) Method of forming a negative charge reversal image on the surface of a transparent dielectric layer (d-1) Erasing mode The potential of the transparent electrode 20 is set to VD>Va. At this time, ■, ≧V, so δ≦1. Therefore, by electron beam irradiation, the surface of the transparent dielectric layer 22 has a potential of
■Charge a negative charge until becomes 2. Since an electric field is formed in the liquid crystal composite 21 from the transparent electrode 20 toward the transparent dielectric layer 22, the incident light is transmitted and the displayed image is uniformly bright.

(d-21 writing mode The potential of the transparent electrode 20 is set to ``■.''Vz. At this time, V<Va, so δ>1. Therefore, the part irradiated with the electron beam is neutralized with positive charges, Transparent dielectric layer 22
A negative charge reversal image is formed on the surface. Liquid crystal complex 21
The electric field in the area becomes weaker in the area irradiated with the electron beam, so the display screen becomes dark (the area written by the electron beam is dark).

Next, there are two types of methods shown below in the above method (B).

(el Method of forming a negative charge reversal image on the surface of a transparent dielectric layer (fl Method of forming a positive charge reversal image on the surface of a transparent dielectric layer) In the methods (e) and (fJ above), the potential of the transparent electrode V
ゎ is set to L < L < Va.

These methods will be explained in detail below.

(el) Method of forming a negative charge reversal image on the surface of the transparent dielectric layer (e-L) The potential vc of the erase mode collector 10 is set to negative polarity, and an electron beam with a sufficiently large current value is applied to the surface of the transparent dielectric layer 22. From the conditions of V, <V, and <V, the secondary electron emission ratio of the transparent dielectric layer is δ>l, but the emitted secondary electrons are
. Because of its negative polarity, it is not collected by the collector and is pushed back to the surface of the transparent dielectric layer. Therefore, the potential on the surface of the transparent dielectric decreases to vl, and the surface of the transparent dielectric becomes uniformly negatively charged. At this time, an electric field is generated in the liquid crystal composite 21 from the transparent electrode 20 toward the transparent dielectric layer 22, and the incident light is transmitted without being scattered.

Therefore, the displayed image becomes uniformly bright.

(e-2) Write mode The potential ve of the collector IO is made positive and electron beam writing is performed. If vc is made sufficiently thick (and secondary electrons emitted from the surface of the transparent dielectric layer 22 are collected, positive charges will be generated in the transparent dielectric layer according to the current value of the writing electron beam under the condition of δ>1). This neutralizes the negative charges that are added to the surface and has previously been formed in a -like manner, and an inverted image of the negative charges is formed.When light is incident on the liquid crystal composite 21,
Light is scattered according to the amount of neutralization, and the displayed image is in a dark state (
The area written by the electron beam becomes dark).

(f) Method of forming a positive charge inversion image on the surface of the transparent dielectric layer (f-11 The potential of the erase mode collector lO is set to positive polarity, and the transparent dielectric layer 22 is irradiated with an electron beam with a sufficiently large current value) do.

V + < V. From the condition of <v2 (δ>1), if the potential of vc is made sufficiently large (and the secondary electrons emitted from the surface of the transparent dielectric layer are collected by the collector, the potential of the surface of the transparent dielectric layer will reach v2). The surface of the transparent dielectric layer is uniformly positively charged.At this time, an electric field is generated in the liquid crystal composite 21 from the transparent dielectric layer toward the transparent electrode, and the incident light is transmitted without being scattered. The displayed image becomes uniformly bright.

(f-2) Potential ■ of the write mode collector 10. The secondary electron emission ratio of the transparent dielectric layer 22 is δ>1 due to the condition that L < V- < VD, in which electron beam writing is performed with negative polarity, but the emitted secondary electrons are For sex, collector 10
is pushed back to the surface of the transparent dielectric layer without being collected. Therefore, the positive charges that were uniformly formed in advance are neutralized, and an inverted image of the positive charges is formed. When light is incident on the liquid crystal composite 21, the light is scattered according to the amount of neutralization, and the displayed image becomes a dark state (the part written by the electron beam is dark).

When continuously displaying images or data patterns, in addition to the basic method of repeating one of the six methods (a) to (f) above, there is a method that uses a combination of these methods. . In particular, (a) and (C) or (b) and (d
), or a method of combining (e) and (f) and using these alternately, the display time of the two combined methods is the same, and the correlation between images that are adjacent to each other on the time axis, such as TV images. When the voltage is strong, the DC electric field component applied to the liquid crystal composite becomes the smallest, and this is a practical method that can maximize the durability of the liquid crystal composite.

FIG. 4 is an example of another configuration of the electron beam writing type spatial light modulation tube according to the present invention. In the figure, 1' is a writing electron gun, 1'' is an erasing electron gun, 15' is a writing electron beam, and 15'' is an erasing electron beam. In the configuration shown in the figure, the acceleration voltage of the erasing electron beam is
It is necessary to set the potentials of the two electron guns so as to satisfy the conditions described in the two basic operating methods (A) and (B). For example, when forming a positive charge image or a negative charge image on the surface of the transparent dielectric layer of the target 9 (method (a) or (c) of (A)), the acceleration voltage of the erasing electron beam is
Second cross voltage (v2) at which δ on the surface of the transparent dielectric layer becomes 1
It is necessary to set the potential of the erasing electron gun so that it matches .

In the spatial light modulation tube of the present invention shown in FIG. 4, writing and erasing are performed using a plurality of electron guns, so compared to the spatial light modulation tube using a single electron gun shown in FIG. It has the characteristic that a certain time difference is given between the writing electron beam and the writing electron beam so that they can be scanned simultaneously. That is,
First, the past charging state on the target is erased with an erasing electron beam, and then the target is charged with a writing electron beam. By continuously performing this operation over the entire screen, it is possible to make the charging time of all pixels the same, and it is possible to display a bright image without shading.

Furthermore, the spatial light modulation tube shown in Fig. 4 has a configuration in which the traveling directions of the electron beams emitted from two electron guns are significantly different; It is also possible to irradiate different locations on the target with two electron guns.

Furthermore, in the spatial light modulation tube shown in FIG. 4, an anode electrode (not shown) is provided between the two electron guns 1' and 1'' and the target 9 to accelerate electrons along the wall surface of the vacuum chamber 11. It is also possible to provide

The aperture 29 in the optical system of the electron beam writing type spatial light modulation tube according to the embodiment of the present invention shown in FIGS. 1 and 4 described above blocks most of the scattered light and displays only non-scattered light. , has the function of improving the contrast of the display screen.

FIG. 5 shows another example of the structure of the target 9 of the beam writing type spatial light modulation tube according to the present invention. In the same figure, 19'
is a transparent dielectric thin film that accumulates and neutralizes charges by secondary electron emission, which is performed in the transparent dielectric layer of the target 9 shown in FIG. 1, FIG. 2, or FIG. 4. This target has the advantage that the resolution of the displayed image is higher than the target having the structure shown in FIG. 1, FIG. 2, or FIG. 4.

An example of a method for producing the target 9 including the liquid crystal composite shown in FIG. 5 will be described below.

(a) First, the transparent electrode 20 is attached to one side of the transparent substrate 19 using a vapor deposition method, a high frequency sputtering method, or the like.

(b) Next, a liquid crystal, a liquid crystal, a polymerization initiator, and the like are mixed, and this mixed solution is uniformly applied to the surface of the transparent electrode using a spin coating method or the like.

(c) A liquid crystal composite 21 in which the resin matrix 24 and the liquid crystal 23 are separated and dispersed from the mixed liquid is formed by an ultraviolet irradiation method or a heating method.

(d) removing the liquid crystal on the surface of the liquid crystal composite 21;

(e) Liquid crystal composite 21 formed by spin coating method etc.
Apply a mixture of monomer and polymerization initiator to the surface of the sample.

(f) A transparent resin layer is formed from this mixed solution by an ultraviolet irradiation method or a heating method.

FIG. 6 shows another example of the structure of the target of the electron beam writing type spatial light modulation tube according to the present invention. In the configuration shown in the figure,
A transparent electrode 20 is placed on the face plate 11° of the vacuum container 11.
A liquid crystal composite 21 and a transparent dielectric layer 22 are further adhered thereon.

As yet another example of the structure of the target of the electron beam writing type spatial light modulation tube according to the present invention, there is a structure (not shown) in which a thin film material (for example, MgO thin film) having a large secondary electron emission ratio δ is adhered to the surface of the target. . For example, Figure 1,
By depositing the thin film material on the surface of the transparent dielectric layer 22 in FIGS. 2, 4, and 6, and on the surface of the transparent dielectric thin film 19' in FIG. efficiency can be increased.

Furthermore, a target having characteristics of a plurality of configurations among the target configurations shown in FIGS. 2, 5, and 6, and a target configuration in which a thin film material with a large secondary electron emission ratio δ is attached to the target surface; It is also possible to construct an electron beam writing type spatial light modulation tube having a combination of the characteristics of the various targets described above by using one or more electron guns.

[Effects of the Invention 1 As explained above, according to the present invention, the following unique effects can be obtained.

(2) Since the electron beam writing type spatial light modulation tube of the present invention does not require a polarizing plate, the displayed image is more than twice as bright as that of the electron beam writing type spatial light modulation tube using a conventional polarizing plate.

■There is no need for an alignment layer for aligning liquid crystal molecules used in conventional electron beam writing type spatial light modulation tubes, and it is easy to produce a large-area target, so it is bright and large with high resolution. Images of area can be easily displayed.

■Since the phase of light is not modulated using the birefringence effect of the liquid crystal, there is less unevenness in density on the display screen caused by uneven thickness of the liquid crystal layer.

(2) It is not necessary to enhance the parallel characteristics of the display light incident on the spatial light modulation tube, and the light emitting area of the display light source may be relatively large, so a bright display image can be obtained.

(2) Compared to a spatial light modulation tube using twisted nematic liquid crystal, the electron beam writing type spatial light modulation tube of the present invention has a faster response. That is, the total rise and fall times of the spatial light modulation tube used in the present invention are set between several milliseconds and several tens of milliseconds by controlling the size of the granular liquid crystals in the liquid crystal composite. This is much shorter than the total rise and fall times (from 50 milliseconds to several hundred milliseconds) of a conventional electron beam-written spatial light modulation tube using a twisted nematic liquid crystal.

(2) Since the γ value of the liquid crystal composite used in the present invention is small, it is optimal for analog optical modulation. On the other hand, the γ of the twisted nematic liquid crystal constituting the conventional electron beam writing type spatial light modulation tube is large (unsuitable for analog light modulation).

(2) A bright image without shading can be displayed by using multiple electron guns and simultaneously scanning the target with a fixed time difference between the erasing electron beam and the writing electron beam.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing an embodiment of the electron beam writing type spatial light modulation tube of the present invention, FIG. 2 is a perspective view showing an example of the configuration of the target of the components shown in FIG. 1, and FIG. 2 shows an example of the secondary electron emission characteristics of the transparent dielectric layer of the target shown in FIG. 2. FIG. 4 shows another embodiment of the electron beam writing type spatial light modulation tube of the present invention. FIG. 5 and FIG. 6 are schematic diagrams showing other embodiments of the target of the electron beam writing type spatial light modulation tube of the present invention, and FIGS. 1 is a schematic diagram showing the configuration of a conventional electron beam writing type spatial light modulation tube described in literature and its constituent elements. DESCRIPTION OF SYMBOLS 1...Electron gun, 2...Cathode, 3-7...Grid, 8...External coil, 9...Target, lO...Secondary electron collecting electrode 11... Vacuum container, 11°...Transparent face plate, 12~14...
・Reed Masen, 15... Electron beam, 16... Incident light, 17... Display light, 26... Light source, (collector) 27... Ultraviolet cut filter 28... Lens, 30. ··screen.

Claims (1)

[Scope of Claims] 1) Between the transparent dielectric layer and the transparent electrode, the ordinary refractive index, the extraordinary refractive index of a nematic liquid crystal, cholesteric liquid crystal, or smectic liquid crystal, or the refractive index when the liquid crystal is randomly oriented. A structure in which the liquid crystal is dispersed and confined in a transparent resin matrix having an equivalent refractive index,
Alternatively, a target in which a liquid crystal composite having a structure in which the resin matrix is dispersed and confined in the liquid crystal is inserted in close contact with the transparent dielectric layer and the transparent electrode, and the generation of electrons and the formation, acceleration, and focusing of an electron beam. one or more electron guns consisting of a cathode and one or more grids for controlling the electron beam intensity according to an input signal; and a secondary electron collector for controlling the charge on the surface of the transparent dielectric layer. An electron beam writing transmissive spatial light modulation tube that combines a vacuum container containing an electrode and an electron beam deflection system that deflects the electron beam. 2) The electron beam writing type transmission type spatial light modulation tube according to claim 1, further comprising a target in which a transparent dielectric layer, a transparent electrode, a liquid crystal composite, and a transparent dielectric thin film layer are successively adhered. 3) The electron beam writing type transmission type spatial light modulation tube according to claim 1 or 2, characterized in that the electron beam writing type transmission type spatial light modulation tube has a target using a face plate of a vacuum container instead of the transparent dielectric material in close contact with the transparent electrode. 4) The electron beam writing type transmission type spatial light modulation tube according to any one of claims 1 to 3, characterized in that a thin film material having a high secondary electron emission ratio is attached to the target surface. 5) The electron beam writing type transmission space according to any one of claims 1 to 4, wherein the optical system has an aperture that passes non-scattered light and blocks scattered light, or an aperture that has the opposite effect. light modulation tube. 6) The electron beam writing type transmission type spatial light modulation tube according to claim 1, wherein the target is simultaneously scanned with a fixed time difference between the erasing electron beam and the writing electron beam.