JPH04194976A - Light shielding plate and display formed by using this light shielding plate - Google Patents

Abstract

PURPOSE:To obtain the light shielding plate which can be applied even to displays having fine display dot pitches by using a pair of specific metals, thereby integrally forming the light shielding plates having many light shielding parts and decreasing the pitches of the light shielding parts. CONSTITUTION:The light shielding plate is formed by providing apertures on a metallic plate having <=300mum thickness. Etching is general as a means for providing such apertures. Exact etching is difficult and the etching time is long; in addition, the dealing with displays having fine display dot pitches is not possible, if this thickness is larger than 300mum. Even the light shielding plates having the many light shielding parts are integrally formed and the light shielding plates which can be applied to the displays having the fine display dot pitches are obtd. by diminishing the light pitches of the light shielding parts.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a light shielding plate and a display using the light shielding plate, and more specifically, the present invention relates to a light shielding plate and a display using the light shielding plate. The present invention relates to a light-shielding plate capable of blocking light and a display incorporating the light-shielding plate.

[Prior Art] Generally, there is an optical filter that has light blocking performance. Although this device controls the transmission of light of a specific wavelength or adjusts the amount of white light, it cannot specify the direction of the light.

On the other hand, in the field of displays, particularly in self-luminous or non-luminous transmissive displays, the following problems exist.

That is, one problem is that external light enters the display, significantly reducing the contrast. Another problem is that if the display is placed in an environment surrounded by highly reflective surfaces, the reflection of light from the display can cause glare and inconvenience. To address these problems, it is common practice to design the environmentally optimal position and angle when installing the display, and to avoid highly reflective surfaces.

However, it is difficult to optimally design a display for moving external light such as the sun, or in a moving body where external light is incident.Once the contrast is determined, the optical filter
However, since a decrease in brightness is unavoidable, it is necessary to increase the light source brightness by that amount. Further, in the cockpit of a moving object such as an airplane or a car, a glass surface is essential for viewing the outside, so highly reflective surfaces cannot be avoided. In such an environment, the display must be installed in the optimal position in the cockpit to avoid dazzle caused by reflected light, but since the cockpit is a limited space, it is necessary to optimally design the display's installation position, angle, etc. In fact, it is difficult to do so. The above-mentioned optical filter does not contribute to solving this problem at all.

Therefore, should light be passed in a specific direction, that is, towards the viewer?
It is understood that the use of a light shielding plate that blocks light in other or unnecessary directions is effective in the display field described above.

Here, the basic structure of the light shielding plate will be explained.

Figure 1 is a cross-sectional view of a light-shielding plate placed perpendicular to the visual direction, in which light-shielding parts of l+a and thickness t are formed perpendicularly to the visual direction, alternating with light-transmitting parts of the width. Ru. P=a can be formed at a constant pitch or can be formed at uneven pitches, but the angle for complete light shielding is θ= ian' (t/
b) becomes the minimum one.

In addition, in the following explanation, the one with a shade pitch will be explained.

Next, FIG. 2 shows the planar shape of the light shielding plate.

In FIG. 2, the solid line portion corresponds to a in FIG.

FIG. 5(a) shows a striped light shielding portion, and the light shielding direction is downward ``1'' in the figure. In order to make this light shielding plate integral, ears may be provided at both ends as shown in the figure. Same figure (b)
indicates a rectangular lattice-shaped light-shielding portion, and the light-shielding directions are vertical and horizontal directions in the figure. Other examples of grid shapes are rectangles,
Triangles, hexagons, etc. can be used. FIG. 3(e) shows a concentric light-shielding portion, and the light-shielding direction is all directions from the center point.

The planar shape of the light shielding plate can be appropriately selected from the shapes shown in (a) to (e) and many shapes obtained by modifying these shapes.

Next, the characteristics required of the light shielding plate are as follows.

(1) Easy to form, (2) Easy to handle,
(3) good weather resistance, (4) thinness, (5) small minimum display dot pitch of applicable displays, (6) ability to transmit a large amount of light, (7) light shielding angle of 30 to 60 degrees. (8) When built into a display, the abrasive quality must be compatible with the display production process.

To supplement (5) above, there is a hood type display that does not have a light shielding part above the display, but this is inconvenient because it requires a considerable height in order to obtain a light shielding angle of 30 to 60 degrees.

Further, if the light shielding angle (7) is smaller than 30°, the light shielding performance is poor, and if it is larger than 60°, the viewing angle is narrow, making it difficult to see.

The following are known as light shielding plates having some of these characteristics.

One is to use a transparent film (generally an organic substance) for the light-transmitting part and an opaque film (generally a metal foil) for the light-shielding part, and then alternately stack and press them together, and then press them perpendicularly to the lamination direction. This is a method to obtain a plate-shaped light shielding plate by cutting. Instead of metal foil, it is also possible to use metal vapor deposition or plating on a transparent film, and for pressure bonding, a method such as adhesive or thermocompression bonding is used.

This method is effective because the light shielding part ri a is very small, so the amount of transmitted light can be increased, and it is possible to obtain thin striped light shielding parts with a narrow pitch. 2. It is also difficult to cut them thinly [11] The wider the material, the more difficult it becomes. Also,
In general, organic materials have poor weather resistance, problems with heat resistance and chemical resistance, and gas release and gas permeation, so they cannot be used as built-in displays.

Another method is to use a thin strip of metal plate. The first metal band and the second metal band are overlapped and joined by welding, brazing, etc. at appropriate intervals, and the third metal band is overlapped on top of the second metal band, and the third metal band is placed on top of the second metal band and separated from the above-mentioned joint part. Join at the point. Thereafter, by repeating the same operation and stretching the obtained product in the lamination direction, a mesh-like light shielding plate is obtained. Although this method is superior to the former in that it does not require cutting and is made of metal, it has the disadvantage that the number of layers required to obtain one light shielding plate is very large. Further, it is difficult to cut the metal plate too thinly, and it is difficult to laminate intermediate metal plates.

As described above, these methods cannot produce thin light-shielding plates, and therefore cannot be applied to displays with a fine dot pitch.

[Problems to be solved by the invention] The present invention has been made in view of these problems of the prior art.
Even in the case of a light-shielding plate having a large number of light-shielding parts, the light-shielding plate can be formed by collectively forming the light-shielding parts and the pitch of the light-shielding parts can be reduced to provide a light-shielding plate that can be applied to displays with a fine display dot pitch. The purpose is to provide this information as well.

[Means and Effects for Solving the Problems] In order to solve the above-mentioned problems of the prior art, the inventors of the present invention, as a result of intensive studies, have etched a metal plate with a thickness of 300 μm or less to provide an opening. By using as a light shielding plate,
The present invention was completed based on the finding that the present invention can be applied to displays that are thin and have a fine dot pitch.

That is, the present invention provides a light shielding plate characterized by being formed of a metal plate having a thickness of 300 μm or less and having a plurality of openings and having a light shielding performance in a specific direction, and a light shielding plate installed inside the light shielding plate. It's on display.

Hereinafter, the light shielding plate and display of the present invention will be explained in more detail.

The light shielding plate of the present invention has a thickness of 300 μm or less, preferably 5 μm or less.
It is created by providing an opening in a metal plate with a thickness of 0 μm or less. Etching is a common method for providing such openings.

If the plate thickness is greater than 300 μm, it is difficult to perform accurate etching, the etching time is long, and it is not possible to handle displays with fine display dot pitches.

The light shielding plate of the present invention is made of metal. Even if the plate material is made of a light-shielding organic material, the light-shielding function is sufficient, but as mentioned above, there are problems such as poor weather resistance and the inability to incorporate it into a display. Further, if the plate material is made of a light-shielding inorganic material, there is a problem that it is brittle and has poor workability. On the other hand, if metal is used, a useful light shielding plate can be formed without the above-mentioned drawbacks. For such metals, use metals with high corrosion resistance or
Corrosion resistance can be improved by commonly used surface treatments or coating techniques.

For etching to provide the openings, ordinary metal etching techniques can be applied as is.

It has a cross-sectional shape as shown in Figure 1, and - in Figure 2.
- Etching of the surface shape as illustrated can be carried out easily. Here, the shape that can be etched and the light shielding performance will be explained. If the thickness of the metal plate that is generally etched is t, the minimum opening diameter or 111 that can be obtained is approximately 1.4t.
It is known empirically that Further, the minimum Ill of the light shielding portion is approximately 0.4t.

Therefore, the maximum shading angle θ of the shading plate obtained from one metal plate
1 is θr = van' (t/ 1.4t) = 35.
The maximum shading angle θ of two shading plates of equal thickness is 5°.
2 is θ2-jan' (2t/L, 4t) = 5
It is 5°. Therefore, if the light-shielding angle is less than this, it can be designed as desired by widening and adjusting the width of the light-transmitting part.

The amount of light transmitted depends on the light shielding angle, the light shielding pitch, and the pattern. For example, the amount of light transmitted by a light shielding plate with a minimum pitch and a maximum shielding angle in a striped pattern is a = 0.
4t, b −], 4t, so L, 4t/
(0.4t + 1..4t) X 1.00-
10 = approximately 78%.

By increasing a and increasing the pitch, it is possible to reduce the amount of light transmitted at the same shielding angle. Furthermore, the amount of light transmitted can be increased by increasing b, increasing the pitch, and decreasing the shielding angle. Combining the above operations and selecting the surface shape of the light shielding part,
In addition, by stacking the light shielding plates, it is possible to obtain a light shielding plate that has the amount of transmitted light at a fairly wide range of light shielding angles and has an appropriate light shielding direction.

Generally, the light-shielding angles of the negative light-shielding plates occur symmetrically with respect to the light-shielding pitch direction, as shown in FIG. but,
When two or more light-shielding plates are stacked, it is possible to obtain light-shielding plates with asymmetrical light-shielding angles by shifting the light-shielding parts within the overlapping range.

The light shielding plate obtained in this way is used by being installed between the display part and the sensing part of the display, but it is generally preferable to place it on the display surface or adhere it with a transparent adhesive or the like. be.

Next, the relationship between the display dot pitch Pd of the applied display and the light shielding pitch Pf' of the light shielding plate will be explained.

The display dot pitch here may also be referred to as the resolution of the display pattern. When the ratio of Pd to Pr is large, for example 3 or more, the viewing angle is not so small even if the light emitting part or the light transmitting part of the display is far from the light shielding plate. However, when Pd/PI' is 1, unless the above-mentioned two are close to each other, the viewing angle becomes narrow and it becomes difficult to see. Pd
A small diameter means that high resolution and high quality display is possible, and generally 400 μm is used, but for high resolution it is 100 μm.
μm is required. When designing a light-shielding plate with less viewing angle dependence for Pd=100μm, when Pd/Pf=3, the thickness will be 20μm or less, and a in Figure 1 will be less than 8μm, making it similar to a light-shielding plate made of metal. However, the workability deteriorates. In this case, as described above, it is desirable to set <Pd/Pf=1 and place the light shielding plate close to the light emitting part or the light transmitting part of the display. However, since a typical display has glass on its display surface, it is impossible to get closer than the thickness of the glass.

A way to solve this problem is to incorporate a light shielding plate into the display. The problem in this case is matching with the display manufacturing process and materials.

Regarding corrosion resistance, as mentioned above, if it is a metal,
Alternatively, it can be used sufficiently by surface treatment. Heat resistance and oxidation resistance can also be used in the same manner since the temperature normally used in the display production process is about 600° C. or lower. The coefficient of thermal expansion of the material is an issue related to temperature. When a light shielding plate is built into a display, it needs to be fixed to a container or the like. Since a portion of the container is made of glass, other parts of the display that undergo a thermal process are designed to accommodate the thermal expansion of the glass. That is, the thermal expansion coefficient of the material should be approximated to that of glass, or the film should be made thinner to reduce stress.

Therefore, it is necessary to select a light shielding plate according to the present invention whose coefficient of thermal expansion is close to that of glass. The coefficient of thermal expansion of commonly used glass is 40 to 100XIO.
-'/°C (30 to 450°C), and examples of metals that meet this are Fe alloys with 150% N by weight and F alloys with 8% by weight of N142 and Cr.
e alloy, and for hard glass, Ni2O wt%
-0017% by weight Fe alloys or alloys similar to these alloys can be preferably used. If the coefficient of thermal expansion of the material is not taken into consideration, a large stress will be generated during cooling during the thermal process, which may deform the light shielding plate or damage the glass portion of the container.

If the coefficient of thermal expansion of the metal is selected in this way, it is easy to incorporate the light shielding plate into the display.

The light shielding plate can be installed inside the display using a mechanical method, pressure welding, welding, brazing, or various adhesives. In addition, if there is a risk of short-circuiting due to contact with electrodes or wiring inside the display, it is preferable to cover part or all of the surface of the light-shielding plate with a dielectric material using various well-known surface treatment methods.

FIG. 3 shows a schematic cross-sectional view of a display with a built-in light shielding plate. 1 is a light shielding plate, 2 is a display dot, 3 is a front glass plate, and 4 is a rear glass plate. The advantage of having a built-in light shielding plate is that
Another advantage of this method is that it can be applied to the high-resolution displays mentioned above, and there are no mechanical problems such as thickness ratio or environmental resistance problems such as dust and humidity.

Another advantage is that it can also be used as an electrode for a display. For example, it can be used as an anode, a control grid, and a charge prevention electrode in a fluorescent display tube, a common electrode, anode, and a cathode for auxiliary discharge often used in plasma displays, and an anode in a flat CRT.

Therefore, it is effective to incorporate a light shielding plate not only in high-resolution displays but also in general displays. It goes without saying that manufacturing methods for various displays can be applied as is, except for incorporating a light shielding plate, and there is no need to add any complicated steps.

Therefore, the light shielding plate of the present invention has a minimum display dot pitch of 6
It can also be used for displays of 00 μm or less, and even 100 μm or less.

Examples of such displays include self-luminous or non-luminescent transmissive displays such as fluorescent display tubes, plasma displays, EL displays, and liquid crystal displays.

[Example code] Hereinafter, the present invention will be specifically explained based on Examples.

Example] A light-shielding plate having rectangular holes arranged in a grid pattern was prepared by etching a Fe alloy plate having a thickness of 50 μm and containing 50% by weight Ni. The grid 1J is 20 μm, and the hole rectangle is 70 μm long and 2 wide.
00 μm. The performance of this light shielding plate is 35.5° in the vertical direction.
, 14° in the lateral direction, and the amount of transmitted light was about 70%. A frame of rll 1 mm was formed around the light shielding plate at the same time as etching, and there was no problem in the workability of attaching the display to the light shielding plate.

Furthermore, when this light-shielding plate was thermally oxidized in air at 600° C. for 30 minutes, the reflection on the metal surface was significantly reduced, and the plate was colored darkly, so that the display quality of the display did not deteriorate.

Example 2 The thermally oxidized light shielding plate prepared in Example 1 was
It was placed inside the front glass plate of a 16-inch fluorescent display tube and fixed with low melting point glass. This light shielding plate was connected to ground via a high resistance. Normal fluorescent display tubes have a transparent electrode in this position to prevent static electricity, but by grounding this light shielding plate, antistatic performance was obtained even without the transparent electrode.

In addition, ordinary fluorescent display tubes use soda lime plate glass, and the manufacturing process uses temperatures below 600°C, but the light shielding plate material used in this example has no problems with heat resistance and has no thermal expansion. Since it resembles soda lime plate glass, there was no risk of deformation of the light shielding plate or breakage of the glass.

Furthermore, although the fluorescent display tube is a vacuum tube, there were no problems with the gas characteristics required for this.

[Effects of the Invention] As explained above, the present invention has the following effects.

(2) Since it is possible to form a large number of light shielding parts at once that can accommodate fine pitches, it is possible to provide a light shielding plate that blocks light in a specific direction at a low cost.

= 17 - ■ Since the light shielding plate is made of metal, it has good mechanical properties and environmental resistance.

■ Since the material of the light shielding plate is metal, a display with a built-in light shielding plate can be created, and the light shielding plate can be used as an electrode of the display, which is more economical.

[Brief explanation of the drawing]

FIG. 1 is a partial cross-sectional view for explaining a light-shielding plate, FIG. 2 is a plan view of various types of light-shielding plates, and FIG. 3 is a partial schematic cross-sectional view of a display incorporating the light-shielding plate of the present invention. Patent applicant Noritake Co., Ltd.

Claims (1)

[Scope of Claims] 1. A light shielding plate comprising a metal plate having a thickness of 300 μm or less and having a plurality of openings and having light shielding performance in a specific direction. 2. The light shielding plate according to claim 1, wherein the thickness of the metal plate is 50 μm or less. 3. The light shielding angle of the light shielding plate is 30° when there is only one light shielding plate.
The light shielding plate according to claim 1 or 2, wherein the angle is 45° or more when two sheets are stacked. 4. The coefficient of thermal expansion of the light shielding plate is 40 to 100 x 10^-
Claims 1 and 2 in the range of ^7/℃ (30 to 450℃)
Or the light shielding plate according to 3. 5. A display in which the light shielding plate is installed inside. 6. The display according to claim 5, wherein the light shielding plate is also used as an electrode of the display. 7. The display according to claim 5 or 6, which is selected from a fluorescent display tube, a plasma display, an EL display, a self-emissive type display, or a non-emissive transmissive type display.