EP1164622A2 - Channel plate made of glass for flat pannel displays and method for producing the same - Google Patents

Abstract

Such channel plates typically have a multiplicity of parallel channels (2) which are separated by webs (1) and are microstructured on a flat glass plate (4). The channels (2) are ground, for example, into the flat rectangular glass plate (4) using a high-precision multi-disc grinding tool, which is preferably precision ground plane at least on the side on which the channel structure is incorporated. In order to increase the image and color contrast of the image generated on the flat screen, at least the upper edges of the webs (1) are covered by a non-transparent layer (5). <IMAGE>

Description

The invention relates to a channel plate made of glass for flat screens, which has a plurality of parallel channels separated by webs, are microstructured on a flat glass substrate.

The invention further relates to a method for producing such Channel plate.

Display panels of flat screens, as they are typically used in modern Plasma television screens are required, the so-called plasma display Panel = PDP or Plasma Addressed Liquid Crystal = PALC, need for Their function is called channel plates, which are microstructures of high precision Form of several, parallel microchannels that pass through Webs are separated.

Such a channel plate is shown in detail in FIG. 2 in principle on a greatly enlarged scale. The channel-shaped microstructuring shown in this figure must be carried out inexpensively and in large quantities for different display sizes (screen diagonals up to 60 "and larger). Depending on the screen format, the structure dimensions are in the following areas: spacing X = 50 - 1000 µm, height Y = 50 - 300 µm and web width Z = 20 - 100 µm. For a 42 "HiVision PDP display there are, for example, approx. 5760 channels with a pitch of the webs" X ", the so-called pitch, of approx. 161 µ m with a web height" to produce Y "of 150 μ m and a land width" Z "of 30 μ m with tolerances of a few μ m approximately 520 mm in length.

In the channels between the rib-shaped webs, depending on the display type, each applied between zero and three conductor tracks as electrodes.

The structure of these modern flat screens, in particular the channel plate, is known.
Various methods for forming the channel structure have become known. In one method, the webs are applied in succession to a flat glass substrate in several layers to form channels in a screen printing process. This process is very complex and expensive.

In another method, the channel structures in the flat Molded glass substrate.

This shaping can be done in different ways.

It is known to pass through the channel microstructures by hot forming To produce embossing.

It is also known to sandblast over a mirostructured mask to generate the channel microstructures.

Attempts have also been made to grind the channels structure. Grinding is preferably a highly precise one Multi-disc grinding tool used that several on a common Spindle, with high precision axially spaced apart by spacer rings arranged precision grinding wheels. Because the channels are very fine are structured and have very small distances from each other Manufacture of the duct plates by grinding using the multi-disc grinding tool difficulties in that the individual Grinding wheels of the multi-wheel grinding tool are not in accordance small axial distances can be arranged to each other. For this The distance between the individual grinding wheels is therefore an integer Multiple of the pitch "X" of the webs. Because the length of the Multi-disc grinding tool due to the vibration behavior of the Machining spindle and is limited by the speed, takes place Production of the channel plates then by so-called offset grinding, at due to the multiple overflow of the multi-disc grinding tool Channel plate is structured. Between the individual overflows that will Multi-disc grinding tool offset at right angles to the longitudinal axis of the channel exactly around the pitch to be manufactured.

Such a method of offset grinding is part of the prior art Technology.

It has been shown that in the case of channel plates with channel structures which consist of one flat glass substrate are formed, especially if they are ground by grinding have been worked out, scattered rays or secondary light effects arise, especially when used in a PALC display, at which the channel plate is illuminated on the back.

The invention is based on the object, the one mentioned Channel plate made of glass for flat screens so that the scattered rays or the secondary light effects are reduced and thereby the image and Color contrast of the television picture generated on the screen increased can be.

This task is solved starting from a channel plate made of glass for flat screens, which a variety of parallel, through Bridges has separate channels on a flat glass substrate are microstructured, according to the invention in that at least the upper edge of the webs through a non-transparent layer is covered.

The cover of the top edge of the web prevents leakage of other secondary radiation and thus increases the image and color contrast.

According to a first development of the invention, the channel plate is like this formed that the non-transparent layer has a thickness that is clear is smaller than the depth of the channels, and the channel structures in the Glass substrate are formed.

According to one embodiment, the channel structures are preferably through ground through the non-transparent layer.

As an alternative to this, according to a second development of the Invention be designed so that the thickness of the non-transparent layer is at least equal to the target depth of the channels and the channel structures in the non-transparent layer are formed. Here too, according to one Design the channel structures preferably in the non-transparent Ground layer. This second development of the invention has an effect advantageous on the tool wear and the feed rate when Form the channel structures.

• Bereitstellen einer flachen Rechteck-Glasplatte mit vorgegebenen Abmessungen
• Aufbringen einer nichttransparenten Schicht mit vorgegebener Dicke auf einer Seite der Glasplatte, und Strukturieren der Kanäle durch die nichttransparente Schicht hindurch in dem Glassubstrat oder ausschließlich in der nichttransparenten Schicht mit entsprechender Dicke.

With regard to the method for producing the channel plate, the object is achieved according to the invention with the following steps:

• Providing a flat rectangular glass plate with predetermined dimensions
• Applying a non-transparent layer with a predetermined thickness on one side of the glass plate, and structuring the channels through the non-transparent layer in the glass substrate or exclusively in the non-transparent layer with a corresponding thickness.

According to one embodiment of the invention, the structuring of the Channels by grinding the channels using a high-precision Multi-disc grinding tool through offset grinding.

Further embodiments of the invention are in the subclaims marked and result from the description of the figures.

Using an embodiment shown in the drawing, the Invention explained in more detail.

Fig. 1

in einer zweischrittigen querschnittlichen Prinzip-Darstellung eine Kanalstruktur mit Stegoberkanten, die durch eine nichttransparente Schicht abgedeckt sind,

Fig. 2

die bekannte Kanalstruktur einer Kanalplatte in einer prinzipiellen, idealisierten perspektivischen Darstellung.

Show it:

Fig. 1

in a two-step cross-sectional principle representation, a channel structure with web top edges which are covered by a non-transparent layer,

Fig. 2

the known channel structure of a channel plate in a basic, idealized perspective view.

2 shows an enlarged, highly idealized representation of the well-known structure of a channel plate for modern flat screens. This Channel plate has a plurality of parallel, through webs 1 separate channels 2. On the bottom 3 of the channels are, depending on the display type and execution, 0 - 3 electrodes applied.

The production of such, with features according to the invention provided glass plate happens in the following steps:

First, a flat rectangular glass plate 4, the glass substrate, with given dimensions according to the required screen size, provided. This glass plate is preferably made by floating or pulling made and preferably consists of borosilicate glass.

Glass plates produced in this way typically have on their surface wavy bumps with long wavelength, the so-called "Warp" and a ripple with a very small wavelength. By grinding one or both sides of the glass surface in the The next optional step is to minimize the warps and the Ripple and thus a reduction in the tolerance range of the structured Channel plate. When using a suitable grinding wheel, through the flat-ground glass surface when using the duct plate in one PALC display minimizes distracting stray radiation, and thus the contrast increased.

The glass plate 4 is then covered with a non-transparent cover layer 5 provided, for example by screen printing (step 1 in Fig. 1). The material a glass solder, a screen printing ink, a plastic can be used for the cover or be a metal.

The channels 2 are then formed in step 2 of FIG. 1.

The structuring of the channels 2 in the face-ground, through the layer 5 covered, glass plate 4 is carried out according to one of the above Method, preferably by grinding in the channels by means of a high-precision multi-disc grinding tool.

Such high-precision multi-disc grinding modules typically have several, on a common spindle, highly precise due to spacer rings axially spaced from each other, mounted precision grinding wheels for simultaneous grinding of parallel ones Microstructures in one workpiece. The grinding wheels must be one have high-precision mutual spacing with very small tolerances. For the reasons mentioned at the outset, grinding is carried out Channel structure through the so-called offset grinding described there.

The covering of the top of the web by the layer 5 prevents scattering or. Secondary radiation can escape through the top of the bridge and thus carries to increase the picture and contrast of the television picture.

There are several for the application and the thickness of this cover 5 Possibilities.

For example, in the case of FIG. 1, the thickness of layer 5 is in the range from 10 µm to 1 mm.

Another option is to make the cover so thick that the channels are structured only in the top layer (e.g. Structuring in glass solder), which can be processed much easier. This results in particular in relation to grinding Tool wear and the possible feed rate significant Benefits.

To optimize the topography of the polished glass surface, the Channels 2 are refined after structuring (step 2). This Refinement can e.g. can be realized by etching and is used primarily for Contrast increase and the reduction of stresses in the glass, i.e. one better mechanical stability of the webs 1. The surface quality on Channel floor and the polarization properties of the ground surfaces can be increased so that the properties of the channel plate of the can be adapted later application.

Another possibility of increasing the contrast can be with the introduction of the Electrodes 6 can be reached in the structured channels 2. The brought in Electrodes 6 are not only used to control the plasma cells used, but offer the advantage of non-transparency, disruptive To minimize stray radiation and therefore essential to increase contrast to contribute. In particular, an exemplary arrangement of the electrodes 6 in the corners of the channels (Fig. 1) can prevent unwanted stray radiation, which arises due to the inevitable radii on the channel floor.

Claims (13)

Channel plate made of glass for flat screens, which has a plurality of parallel channels (2) separated by webs (1), which are microstructured on a flat glass substrate (4), characterized in that at least the upper edge of the webs (1) is characterized by a non-transparent layer (5) is covered. Channel plate according to claim 1, characterized in that the non-transparent layer (5) has a thickness which is significantly smaller than the depth of the channels (2) and the channel structures are formed in the glass substrate (4). Channel plate according to claim 2, characterized in that the channel structures are ground through the non-transparent layer (5) into the glass substrate (4). Channel plate according to claim 1, characterized in that the thickness of the non-transparent layer (5) is at least equal to the desired depth of the channels and the channel structures are formed in the non-transparent layer (5). Channel plate according to claim 4, characterized in that the channel structures are ground in the non-transparent layer (5). Duct plate according to one of claims 1 to 5, characterized in that the non-transparent layer (5) consists of a glass solder, or a screen printing ink, or a plastic or a metal. Channel plate according to one of claims 1 to 6, in which electrodes (6) angularly separated in the channels (2), with one leg on Canal floor and the other leg on the adjacent web wall. Channel plate according to one of claims 1 to 7, wherein the channels in Meaning of an increase in contrast and a decrease in tension are chemically refined. Method for producing a channel plate according to one of claims 1 to 8, comprising the steps: Providing a flat rectangular glass plate with predetermined dimensions Applying a non-transparent layer with a predetermined thickness on one side of the glass plate, and Structuring the channels through the non-transparent layer in the glass substrate or exclusively in the non-transparent layer with a corresponding thickness. The method of claim 9, wherein the structuring of the channels by grinding in the channels using a high-precision multi-disc grinding tool done by offset grinding. The method of claim 9 or 10, wherein the material for the Cover a glass solder, or a screen printing ink, or a plastic or a metal is used. Method according to one of claims 9 to 11, wherein the channels according to their structuring in the sense of an increase in contrast and one Stress relief can be chemically refined. Method according to one of claims 9 to 12, wherein the electrodes in the channels are separated angularly in the corners, with a Leg on the channel floor and with the other leg on each neighboring web wall.

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