DE2260523C3 - Light collimator - Google Patents

Description

F i g. 3a and 3b two cross sections through the collimator, each perpendicular to the axes of FIG Cross-section ellipse.

In the conventional execution of the irradiation of the covering means ("resist"), a configuration of the elementary phosphor surface is obtained as shown in FIG. 1. To put it more precisely: The shape of the conventional collimator produces a widening »Sa which is constant along the circumference of the slot 1 of the mask occurs that is, that after the usual developing and washing operations, the individual sections of the strips fuse.

F i g. 2 shows the geometrical relationship which, in each plane, connects the extent A of the light source corresponding to the generated point of the collimator, with the extent of the phosphor elementary surface and the extent Φ of the diaphragm of the shadow mask, which is at a distance Q from the surface of the screen is

Based on the in F i g. 2 it is possible to obtain the dimension A of the light source, given the other parameters, according to the following general relationship:

ellipsoidal collimator, according to the following equation:

A =

KD (C-Q) - 0C

This general relationship can easily be specified to compute the major and minor axes Α, ™ and A _{miX of} an ellipse which is the circumference of the A -

A _n ^ _x -

KD ^ _1x (CQ) -0 _max C

_in (C. -Q) - Q

ίο The letters used have the following Importance:

ax = height of the phosphor strip = d _max ,

KD _m "= width of the phosphor strip = dmin,

C = collimator-screen distance,
Q = mask-to-screen distance,
D _m ax = geometric projection of A _roax ,
Dmm = geometric projection of A _mm , A ™ * = major axis of the collimator,

Amin = minor axis of the collimator,
Φπ ,, η = width of the slot of the mask,
Φτη ₃ * = height of the slot in the mask,
K = correction factor limited by the formation of the phosphor "cover"(<1).

The F i g. 3a and 3b show the dimensioning of the collimator according to the invention. It should be noted that it it is not necessary to show in detail the selection of materials or processing techniques, as these are known from the conventional rotationally symmetrical collimators. The only essential one The difference is that in the shaping or post-shaping machine an elliptical one is used to work To use coupler.

For this purpose 2 sheets of drawings

Claims (2)

Patent claims: 1. Light collimator with an elongated light-emitting one Surface that is used in a device for the exposure of photosensitive layers in the Production of a screen of a color picture tube having a shadow mask with elongated slots serves as a light source and which is oriented so that the longitudinal direction of the exposure during exposure light emitting surface of the light collimator with the longitudinal direction of the elongated slits of the Shadow mask matches, characterized in that the light-emitting surface of the light collimator has the shape of an ellipsoid 2. Light collimator according to claim 1, characterized in that the major and minor axes the ellipse that defines the ellipsoidal shape of the light emitting surface the following relationships are defined: Kfl "(C -Q) - - Q ) - 0 _min C KD _m \ " The letters have the following meanings: Height of the phosphor strip
Width of the phosphor strip
Collimator face distance,
Mask-screen distance,
geometric projection of A _mM ,
geometric projection of A _m ",
major axis of the collimator,
minor axis of the collimator,
Width of the slot of the mask,
Height of the slot of the mask,
Correction factor limited by the formation of the phosphor "cover"(<1). 35 40 45 The invention relates to a light collimator with the features listed in the preamble of claim 1. It is well known that color picture tube screens are made of a dot-like structure will; in particular, the green-blue-red phosphorus dots are arranged in so-called tripeins, of each of which is thus surrounded by phosphor dots that have different colors. The beams from three electron beam generators each fall together through one of the plurality of Holes of the shadow mask on a group of three (tripein). The one common to the three electron beams Magnetic deflection must also work precisely at the edge of the picture and through the right hole the right one Hit phosphor points, because otherwise faibs will arise. The manufacture of the screen for a shadow mask color picture tube isi difficult; it is accomplished by means of well-known photographic technology. The shadow mask tube color registration problem and its manufacturing difficulties have under Among other things, it led to the development of tubes in which the screen is made up of slightly curved color stripe ftriple exists (US-PS 35 98 628). The production of the colored strips is also carried out in accordance with the above-mentioned method Photo technology. The green-blue-red phosphoi will streak generated one after the other by ultraviolet exposure using an elongated light source, a mercury vapor lamp, in an elongated plastic scmtillator with an upstream lens for production Daralleler rays of light is included, or wherein a tubular collimator is used. Thanks to the axially symmetrical collimator, the Mercury vapor lamp emitted light directed to a strip-shaped limited surface from which it is is emitted. The exposure of the screen is finally carried out through the shadow mask, which is also used in the color picture tube. In this way it is understandable to see the shape of the phosphor streak on the screen the output of the collimator is determined. It has also been proposed (DT-OS 22 46 430) for a color picture tube of the shadow mask type with elongated slits the strip-shaped one Fluorescent pattern using an elongated, parallel to the elongated slits of the mask aligned light source. This should - despite the presence of crossbars or Bridging elements between the parts of the shadow mask enclosing the elongated slits give continuous phosphor streaks on the screen after exposure. If a conventional collimator with an axially symmetrical design is used, the desired size grows However, increasing the dimensions of the elongated phosphor strips not only in the longitudinal direction, but also in the transverse direction, as a result of which adjacent colored or phosphor strips overlap. The invention is based on the object of specifying a collimator through which a screen with a striped pattern can be generated in which the dimensions of the individual patterns in the longitudinal direction compared to the strip-shaped openings in the shadow mask are enlarged, so that continuous or almost continuous stripes of phosphorus arise, while the widths of the stripes are opposite to the Widths of the openings in the shadow mask remain unchanged. This object is achieved by the features listed in the characterizing part of claim 1 solved. Another embodiment of the light collimator can be found in claim 2. The invention is advantageous in a better design of the phosphor strips on the screen in their longitudinal extent achieved with better utilization of the luminous flux. An example of the invention is shown in the drawing and will be described below. Included indicates Fig. 1 shows a relationship between phosphor elements and the slits within the mask, as seen once through a conventional collimator and on the other hand are obtained by the collimator according to the invention, F i g. Figure 2 shows a geometrical relationship of the projections of the rays through a shadow mask slot and the screen of the picture tube and