JPS6314454B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an exposure apparatus for a color picture tube fluorescent surface.

2. Description of the Related Art Conventionally, a shadow mask type color picture tube fluorescent surface exposure apparatus shown in FIG. 1 has been used.

That is, a mounting table 14 of an exposure apparatus that contains a substantially elongated light source 11, correction lenses 12, 13, etc.
A shadow mask 15 is attached thereon, a panel 17 covered with a phosphor film 16 containing a photosensitizer is placed, and light from the long light source 11 is projected onto the phosphor film 16 through the opening of the shadow mask 15. This phosphor film 1
A predetermined portion of 6 is exposed to light, and a fluorescent surface is formed through a development process. In this case, the correction lenses 12 and 13 are used to correct the trajectory of the light from the long light source 11 so that it becomes equal to the electron beam of the color picture tube.

In the exposure apparatus described above, the correction lenses 12, 1
3 is made of glass or plastic, and it goes without saying that it is necessary to manufacture and use a correction lens optimally designed for each of the various types of shadow mask type color picture tubes. On the other hand, if the correction lens is made of glass, the storage period is semi-permanent, but there are disadvantages in that it takes a long time to manufacture the correction lens and it is extremely expensive. In comparison, plastics are cheaper, but have the drawback of being easily scratched and susceptible to browning. That is, in any case, manufacturing a different correction lens for each type of color picture tube increases the manufacturing cost of the shadow mask type color picture tube.

The present invention has been made in view of the above-mentioned circumstances, and it is an object of the present invention to provide an exposure device for the fluorescent surface of a color picture tube incorporating a correction lens that can be combined to expose the fluorescent surface of a wide variety of shadow mask type color picture tubes. It is an object.

Next, an embodiment of the exposure apparatus of the present invention will be described with reference to FIG.

That is, a shadow mask having a slit-shaped opening 25 1 is placed on the mounting table 24 of the exposure apparatus which houses the substantially elongated light source 21, the correction lens ₂₂ , the first correction lens 23 ₁ , and the second correction lens _{23 2} . A panel 27 is placed on which a phosphor film 26 containing a photosensitive agent is attached. In this case, the axis connecting the centers of the long light source 21 and the panel 27 is
Assuming that the longitudinal axis of the slit-shaped opening 25 ₁ is the Y-axis and the axis perpendicular to this Y-axis is the Z-axis, the long light source 21 is provided along the Y-axis, and the slit-shaped opening 25 of the shadow mask 25 ₁ , the phosphor layer 26 is exposed in a strip along the Y axis.

Next, the second correction lens 23 ₂ will be explained. This second correction lens 23 ₂ allows light to pass through it in a manner approximating the trajectory caused by the vertical deflection of the electron beam of the color picture tube, and its axis is It is a cylindrical lens that is provided perpendicularly to the longitudinal direction of the long light source 21, that is, along the Z axis, and has a curved surface with an approximately semicircular cross section, but the curved surface does not have a single curvature. The thickness distribution x ₁ of the cross-sectional shape of the correction lens 23 ₂ along the Y axis is expressed by the formula x ₁ = ₆ 〓 ⁱ⁼⁰ α _i y ⁱ , α ₀ = 8.0 α ₁ = 0 α ₂ = −0.20984×10 ⁻² α ₃ = 0.711196×10 ⁻⁴ α ₄ = −0.904043×10 ⁻⁶ α ₅ = 0.521719×10 ⁻⁸ α ₆ = −0.114555×10 ^−10. It is formed into a curved surface that includes.

The first correction lens ₂₃₁ is designed to pass light in a manner similar to the trajectory of the horizontal deflection of the electron beam of the color picture tube, and its axis is aligned along the longitudinal direction of the long light source 21, that is, the Y axis. Although it is a cylindrical lens having a curved surface with an approximately semicircular cross-sectional shape, the curved surface does not have a single curvature. For example, the thickness distribution x of the cross-sectional shape of the first correction lens ₂₃₁ along the Z axis ₂ is expressed by the formula regardless of the Y-axis direction: x ₂ = ₆ 〓 ⁱ⁼⁰ β _i Z ⁱ β ₀ = 8.0 β ₁ = 0 β ₂ = 0.411300×10 ^-6 β ₃ = 0.553732×10 ^-4 It is formed into a curved surface including a higher-order term such that β ₄ =−0.274253×10 ⁻⁶ β ₅ =0.329906×10 ⁻⁸ β ₆ =−0.120839×10 ⁻¹⁰ .

That is, it is desirable that the curved shapes of the second correction lens 23a and the first correction lens ₂₃₁ are different from each other as described above, and the positions of the first correction lens ₂₃₁ and the second correction lens ₂₃₂ are changed. It is also possible to have a curved surface shape, that is, x ₁ = ₆ 〓 ⁱ⁼⁰ α _i ′Z ⁱ , x ₂ = ₆ 〓 ⁱ⁼⁰ β _i ′y ⁱ , and the order can be a higher order term of 6th or higher order. be.

Next, the correction lens 22 is usually a flat lens with a taper, and performs so-called degrouping correction to correct the deviation from the center of the two electron beams on both sides that are not at the center among the three electron beams of the color picture tube. It's a lens.

The above-mentioned correction lens is designed as follows. First, the first correction lens 23 ₁ is designed to approximate the trajectory of the electron beam due to horizontal deflection. This is determined solely by the characteristics of the horizontal deflection yoke. However, when determining the curvature coefficient, it is necessary to take into consideration the maximum or minimum thickness of the correction lens 22 and the second correction lens 23 ₂ . Next, the lens curved surface of the second correction lens ₂₃₂ is designed to reflect the characteristics of the diagonal portion of the panel 27 of the color picture tube, and the intermediate portion between the vertical axis Y and the diagonal axis. Further correction is added to the diagonal part of the correction lens 23 ₁ ,
It is designed to approximate the trajectory of the vertical deflection of the electron beam. The design of the correction lens 22 may be such that the taper is determined so that the spacing between the phosphors corresponding to the inner electron beam is uniform throughout the screen, and the band-shaped phosphor corresponding to the central electron beam is exposed. In some cases, it is not necessary.

As mentioned above, conventional correction lenses do not separate the characteristics of the horizontal and vertical deflection yokes and include both correction characteristics in a single correction lens, so the positional relationship between the electrical centers of the horizontal and vertical coils is However, in the present invention, the first correction lens 2
The characteristics can be changed simply by changing the relative positions of 3 ₁ and the second correction lens 23 ₂ . That is, for example, the correction lens 22, the first correction lens 23 ₁ ,
When the second correction lens 23 ₂ is combined with the long light source 2
The distance from 1 to each correction lens is DX1,
If we set DX2 and DX3, D x 1 = 40mm, D x 2
= 50 mm, D x 3 = 65 mm, and if the second correction lens ₂₃₂ is moved up and down by ±5 mm, the beam landing error as a color picture tube will be approximately 40 μm on the horizontal axis (Z axis in Figure 2). Vertical axis (Y in Figure 2)
There is almost no beam riding error in the middle part between the diagonal axis) and the diagonal axis. Furthermore, if the first correction lens ₂₃₁ is moved up and down by ±10 mm, the beam landing as a color picture tube will be 10 to 15 μm in the middle between the diagonal axis and the vertical axis, and there will be almost no error on the horizontal axis. .

That is, in general, the horizontal and vertical coils of the deflection yoke are wound separately and assembled in a subsequent process, but errors in this positional relationship cause electron beam landing errors. However, even in this case, it is possible to deal with this by tilting the second correction lens 23 ₂ or the first correction lens 23 ₁ with respect to the long light source, or shifting it with respect to the optical axis. Furthermore, it is possible to deal with beam landing errors due to differences in influence due to geomagnetism, etc., by means such as rotating the axis. In other words, in any case, it is possible to deal with many changes in optical characteristics by using the same combination of correction lenses.
This not only reduces the number of types of correction lenses, but also incorporates a movable mechanism for the correction lenses into the exposure device, making it possible to use correction lenses even when it is necessary to form fluorescent surfaces for color picture tubes with various characteristics. It can be manufactured without replacement or new design, which is a great advantage in the manufacturing process of color picture tubes.

[Brief explanation of the drawing]

Figure 1 is an explanatory cross-sectional view of a conventional exposure apparatus;
The figure is an explanatory perspective view of an embodiment of the exposure apparatus of the present invention. 11, 21... Long light source, 12, 22... Correction lens, 13, 23 ₁ ... First correction lens, 15
...Shadow mask, 16,26...fluorescent layer,
17, 27...Panel, 23 ₂ ...Second correction lens.

Claims (1)

[Scope of Claims] 1. In an exposure device for a color picture tube fluorescent surface that includes a substantially elongated light source and a correction lens, the correction lens has an axis in the longitudinal direction of the long light source and has a cross-sectional shape. A collar comprising: a first cylindrical lens having an approximately semicircular curved surface; and a second cylindrical lens having an axis perpendicular to the longitudinal direction of the long light source and having an approximately semicircular curved surface in cross section. Exposure device for the fluorescent surface of the picture tube. 2. The curved surface of the first cylindrical lens is formed to pass light in a manner approximating the trajectory of the electron beam of the color picture tube mainly due to horizontal deflection;
Claim 1, characterized in that the curved surface of the cylindrical lens is formed so that the light passes through it in a manner approximating the locus of deflection mainly in the vertical direction.
Exposure device for the fluorescent surface of a color picture tube as described in 2.