JPS6153605A - Light transmission plate - Google Patents

Abstract

PURPOSE:To prevent a more striped pattern and a roughness from being generated on a picture by forming an anti-joint surface to a light shielding film of a transparent substrate, provided on at least one surface of the light shielding film, to a fine and uneven surface. CONSTITUTION:The titled light transmission plate is provided with a light shielding film 15 having plural light transmission parts 19, and a non-light transmission part 20 being a partition wall of this light transmission part 19, and a light transmission plate 13 is installed in front of a display picture 12 of a display element 11. Transparent substrates 17, 18 are joined to at lest one surface (both faces in an example shown in the figure) of this light shielding film 15, and also at least one of anti-joint surfaces 17a, 18a to the light shielding film 15 of the joined transparent substrates 17, 18 is formed to an uneven surface.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a light-transmitting plate that is installed and used in front of a display screen such as a television or computer display.

<Conventional technology> Conventionally, in the display screens of cathode ray tubes (CRTs), liquid crystal display devices, and other various "display elements" used in televisions and computer displays, incoming external light is regulated and the display screen is made up of external light. It is used to prevent a decrease in the contrast of the display screen, or to restrict the diffusion angle of the light emitted from the display screen to within a certain angle so that the light from the display screen is not reflected on nearby objects. "
"translucent plate" is generally known. For example, Figures 6 and 7
As shown in the figure [see JP-A-57-189439], a liquid photosensitive resin containing fine particles of silica is applied onto a transparent substrate 1, ultraviolet rays are irradiated through a negative film, and unexposed areas are removed. Only the cured photosensitive resin 2 as a "light-shielding film" is colored to become opaque, and a light-transmitting plate 3 is used to regulate outside light that enters at a relatively large angle of incidence. Refer to Fig. 51-75456, which shows a light shielding film 7 obtained by planing a thermoplastic transparent resin plate 4 from a large number of laminated blocks with a light scattering layer 5 and a colored adhesive N6 interposed therebetween. There is a light-transmitting plate 8 which is sandwiched between transparent plates (not shown) to restrict the incidence of external light in the same manner as the light-transmitting plate 3 described above.

<Problems to be Solved by the Invention> However, when such a conventional transparent plate 3.8 is actually installed in front of a display screen such as a television, as described above, the contrast of the display screen due to external light is affected. Although it is possible to prevent deterioration, the combination of the transparent plate 3.8 and the display screen may cause many so-called "moiré stripes" to appear on the display screen, or the outline of the image reflected on the display screen may become unclear. This causes a phenomenon in which the uniformity of the image is impaired. The occurrence of this moire striped pattern can also be prevented by making the arrangement direction of the non-transparent parts in the light-shielding film intersect with the arrangement direction of the phosphors on the television display screen at a certain angle or more. If this happens, the display screen of the television will become rough, which is not very desirable.

This invention was made by focusing on such conventional technology, and even when the display element is installed in front of the display screen, it does not cause "moiré stripes" or "roughness" on the display screen. The purpose is to provide a translucent plate that does not

Means for Solving the Problems> In order to achieve the above object, the inventor conducted various experiments and
As a result of research, regarding the occurrence of the above-mentioned "moire striped pattern" and "roughness" of the display screen, we found that the condition of the surface opposite to the light-shielding film of the transparent substrate that joins the light-transmitting plate to the light-shielding film formed by 11. It was discovered that these factors were closely influenced by each other, and this led to the completion of this invention. That is, the present invention comprises at least a light-shielding film having a plurality of transparent parts through which light passes and non-light-transmitting parts serving as partition walls of the transparent parts, and is installed in front of a display screen of a display element. In the light-transmitting plate used as a light-shielding film, a transparent substrate is bonded to at least one surface of the light-shielding film,
Furthermore, the surface of the bonded at least one transparent substrate opposite to the light-shielding film is formed into a finely uneven surface.

Embodiments The present invention will be explained below based on the drawings. still,
(Explanation that overlaps with the conventional one will be omitted.

1 to 5 are diagrams showing an embodiment of the present invention. Transparent plates 13 are installed at intervals of 51 m in front of a display screen 12 of a cathode ray tube 11 as a "display element" of a small automobile television 10 provided in the center of an automobile instrument panel 9. The small automobile television 10 is placed so that the display screen 12 is easily visible facing the passenger 14.
The light transmitting plate 13 is set upward at 0 degrees and is installed in front of the display screen 12 to prevent the contrast of the display screen 12 from decreasing by regulating the incident angle e of the external light L1 entering the display screen 12. At the same time, the light L2 emitted from the display screen 12
This is to prevent the display on the display screen 12 from being reflected on the side window glass or the like by regulating the diffusion angle θ within a certain range. Specifically, this light-transmitting plate 13 has a light-shielding film (0.45 mm thick) 15 made of a photosensitive resin composition containing 5 wt% of silica fine powder (average particle size 7μ), and a double-sided adhesive tape ( 0,2+u thickness) 16,
It has a structure in which an outer transparent substrate 17 and an inner transparent substrate 18 made of achromatic polycarbonate plates (thickness: 0.51111 mm) are sandwiched and bonded. The purpose of mixing fine silica powder into the light-shielding film 15 (photosensitive resin composition) is to prevent characters and other displays on the display screen 12 from blurring. 20μ, content 3-5
About wt% is preferable.

In addition, the light shielding film 15 is connected to the outer transparent substrate 17 and the inner transparent substrate 1.
8 and 8 because a special liquid and hydrophilic photosensitive resin composition was used when producing the light shielding film 15 in order to easily remove the uncured resin and easily dissolve it in an alkaline cleaning solution. This is to prevent the light shielding film 15 from absorbing moisture in the air and swelling later, and
The light-shielding film 1 uses both transparent substrates 17 and 18 as a protective cover.
This is to prevent dust and dirt from accumulating on the 5. As shown in FIG. 1, this light-shielding Di 15 is arranged in a so-called checkered pattern, consisting of horizontally long rectangular light-transmitting parts 19 through which light passes, and non-light-transmitting parts 20 serving as partitions between the light-transmitting parts 19. doing.

The light transmitting portion 19 is set at an angle θ to the optimum wave 11 that does not reflect the light from the display screen 12 to an external object, that is, an optimum diffusion angle of '24°<θ>54°, which was proposed earlier by the present applicant. Therefore, the ratio between the aperture of the transparent part 19 or the diameter d of the inscribed circle of the transparent part 19 and the depth h of the transparent part 19 is Q, 23 <
a / h < 0.5, and the ratio of the width β of the non-transparent part 20 between the transparent parts 19 and the diameter d is 1, 2 < d /
β is 25. Further, as for the size of the transparent part 19, the vertical diameter dV is 0.38fi, the plate diameter dH is 0.50 mm, and the vertical pitch pV is 0°421n.
The horizontal pitch pH is 0.55 fl. This time, the surfaces 17a and 18a of the outer transparent substrate 17 and the inner transparent substrate 18 opposite to the light-shielding film 15 are made into finely uneven surfaces to generate and display a moire striped pattern on the display screen 12 of the small automobile television 10. I looked into the roughness of Screen 12.

Table 1 below shows the experimental results obtained.

The experiment was conducted in a dark room with a light transmitting plate 1 at a brightness of 500 Jx.
The appearance of the display screen 12 was examined using examples 1 to 3 in which a relatively fine uneven surface was actively provided, and reference examples 1 to 4 in which the surface was not so actively provided. As for the finely uneven surface, 60 degree specular gloss Gl (JISK5400-1
979 6.7), relative gloss G2, center line average roughness R
I tried various values of a(J[5B0601-1982). The relative gloss G2 is the ratio of the 60 degree specular gloss G1 of the finely textured surface to the 60 degrees specular gloss G1 of the untreated smooth surface, expressed as a percentage, and is used to evaluate the condition of the finely textured surface. is the most preferred. Further, the untreated smooth surface shown in the table is a surface without any finely uneven surface, and the untreated smooth surface on the outer transparent substrate 17 side has a 60 degree specular gloss G1 = 128.1% and a relative gloss G2 = 100
%, center line average roughness Ra = 0.05μ, and the untreated smooth surface on the inner transparent substrate 18 side has a 60 degree specular gloss G.
1=168.5%, relative gloss G2=100%, and center line average roughness Ra=0.05μ. The specular gloss of the finely uneven surface was measured using a Suga Test Instruments color computer (SM).
-2 type).

Further, the achromatic polycarbonate plate employed as the outer transparent substrate 17 has substantially uniform transmission and reflection characteristics over the entire visible light region of 400 to 700 nm so as not to impair the color tone of the display screen 120. In addition, when we investigated the relationship between the total light transmittance ratio (%) and the contrast ratio of the achromatic transparent plate, we found that the contrast ratio was around 70% as shown in Figure 5. We found that the achromatic polycarbonate board we used this time also showed a total light vA transmittance ratio (%) of 70.7.
% was adopted. The inner transparent substrate 18 is made of a colorless and transparent material with high light transmittance so as not to reduce the light transmittance of the entire light transmitting plate 13. In addition, the outer transparent substrate 1
If the total light vA transmittance ratio (,1%) of 7 is 85% or more, the display screen 12 will be dazzling and difficult to see, and if it is less than 50%, the overall brightness will be insufficient, so it should be between 50 and 85%. It doesn't matter if it's something.

Now, according to Table 1, in Reference Example 4 in which both the pressure bonding surfaces 17a and 18a of the outer transparent substrate 17 and the inner transparent substrate 18 are untreated smooth surfaces, many concentric moire striped patterns occur. Also, in Reference Example 2, in which the inner transparent substrate 18 side was an untreated smooth surface and the outer transparent substrate 17 side was a finely uneven surface with a large relative gloss G2, a concentric moiré striped pattern was generated. However, in Reference Example 3, in which the same inner transparent substrate 18 side was an untreated smooth surface, no moire striped pattern occurred. This is because the finely uneven surface on the outer transparent substrate 17 side had a relative glossiness G2 of 41.3 and was highly uneven. Therefore, even if the pressure bonding surface 18a on the inner transparent substrate 18 side is an untreated smooth surface, the outer transparent substrate 1
It can be seen that the generation of moiré stripes can be prevented by making the 7 side a finely uneven surface to some extent. In Examples 1 to 3, in which the relative gloss G2 of the finely uneven surface on the outer transparent substrate 17 side was set to 46 to 72.7, no moire stripes were generated. In this way, the relative glossiness G2 is increased [closer to the untreated smooth surface], and the center line average roughness Ra is decreased (as a result, moire stripes and black stripes essentially remain,
The reflection of external scenery on the surfaces (pressure bonding surfaces 17a, 18a) will also increase, and conversely, if the relative glossiness G2 is too small, the center line average roughness Ra will become thick (if it becomes too large, the outline of the perspective image will be distorted). At the same time as blurring and blurring, the function of regulating the diffusion angle of the light L2 from the display screen also deteriorates.In addition, in the above experiment, both the pressure bonding surface 17a of the outer transparent substrate 17 and the pressure bonding surface 18a of the inner transparent substrate 18 are Although the uneven surface is used, as can be seen from Table 1, it is better to provide the pressure bonding surface L8a of the outer transparent substrate 17 than the pressure bonding surface 18a of the inner transparent substrate 18 to prevent moire stripes and roughness. Therefore, if a clear display screen 12 is required to prevent moire stripes or roughness on the display screen 12, at least the pressure bonding surface 17a of the outer transparent substrate 17 should be provided with a finely uneven surface. It is desirable to provide a finely uneven surface with a relative gloss level G2=45 on the outer transparent substrate 17 side.
~73%, center line average roughness Ra = 0.2~0.5μ
The inner transparent substrate 18 side has a relative gloss G2=48 to 10.
0% and center line average roughness Ra=0.05 to 0.4 is most preferable.

In addition, if either the outer transparent substrate 17 side or the inner transparent substrate 18 side is to have a finely uneven surface, 60 degree specular gloss G1 = 40 to 120% is appropriate, and the outer transparent substrate 17 side and the inner transparent substrate When both the 18th sides are finely uneven surfaces, a 60 degree specular gloss G1 of 50 to 110% is appropriate.

Effects> Since the transparent plate according to the present invention has the content as described above, when it is installed in front of a display screen such as a television or computer display, it will not cause the occurrence of "moiré stripes" or display on the display screen. This has the effect of preventing "roughness" on the screen. Further, according to an embodiment of the present invention, two light shielding films are sandwiched between transparent substrates, and the light shielding film is prevented from swelling due to moisture absorption and deformation of the light shielding film due to heat, and a removable light shielding film is formed. It also has the effect of preventing damage caused by external forces. Furthermore, since it can fully demonstrate its original function of regulating the incident angle of external light incident on the display screen and regulating the diffusion angle of light from the display screen within a certain range, it is suitable for use in automobiles. When used in small TVs, it is necessary to provide a hood-like protrusion on the TV to prevent the contrast of the display screen from decreasing due to incident external light, and to block external light and prevent reflections on the outside. There is also the incidental effect of being able to do it at a lower cost since there is no.

[Brief explanation of drawings]

FIG. 1 is an enlarged plan view showing each size of the light-shielding film in a light-transmitting plate according to an embodiment of the present invention, and FIG. 2 is a small-sized automobile television equipped with a light-transmitting plate according to an embodiment of the present invention. Figure 3 is an enlarged sectional view of the transparent plate taken along the line m-m shown in Figure 2. Figure 4 is an enlarged cross-sectional view showing the part indicated by the arrow ■ in Figure 3. Figure 5 is a graph showing the relationship between the total light transmittance ratio and the contrast ratio of an achromatic transparent substrate, Figure 6 is a plan view showing a conventional example of a transparent plate, and Figure 7 is an arrow shown in Figure 6. 8 is a sectional view taken along the line ①-■, and FIG. 8 is a sectional view corresponding to FIG. 9 showing another conventional example of a transparent plate. 3.8.13-- Transparent plate 7.15 --- Light-shielding film ii --- Braun tube (display element) 12-- Display screen 17 --- Outer transparent substrate 17a --- Light shielding of outer transparent substrate Anti-bonding surface 18 to the film... Inner transparent substrate 18a... Anti-bonding surface 19 of the inner transparent substrate to the light-shielding film... Transparent section 20- Non-transparent section dV -... Vertical direction of the transparent section Diameter dll - Plate diameter of transparent part pV - Vertical pitch of transparent part pH - Horizontal of transparent part? Sochi LI - External light L2 ... Light e from the display screen, - Diffusion angle d ... - Aperture of the transparent part or diameter h of the inscribed circle - Depth of the transparent part 1 - Non-transparent part Width of transparent part G1 - Specular gloss G2 - Relative gloss Ra - Center line average roughness Figure 3 Detour treatment Figure 5

Claims (1)

[Scope of Claims] At least a light-shielding film having a plurality of light-transmitting parts through which light passes and non-light-transmitting parts serving as partition walls of the light-transmitting parts,
In a light-transmitting plate used by being installed in front of a display screen of a display element, a transparent substrate is bonded to at least one surface of the light-shielding film, and a surface of the at least one bonded transparent substrate opposite to the light-shielding film is formed into a finely textured surface. A translucent plate that is characterized by: