JPH0316030B2 - - Google Patents

Description

[Detailed description of the invention]

<Technical Field of the Invention> The present invention relates to a display board suitable for various warning display lamps on an automobile instrument panel. <Prior art> As a conventional display board, for example, Figs.
There is something like the one shown in Figure 4. Reference numeral 1 denotes an instrument panel of the automobile, which is mainly composed of a speedometer 2, a tachometer 3, an odometer 4, a trip meter 5, etc., and is also equipped with a clock 6, a drive computer display 7, and a warning lamp 8. Since all of these structures are basically similar, the warning lamp 8 (fuel alarm) will be explained below as a representative.
The warning lamp 8 includes a display board 11 consisting of a display layer 9 printed with pictographs indicating the contents of the warning, a lighting color pigment print 10, and a colored polycarbonate board 11 with a total light transmittance ratio of 15%. It is connected to a light source 13 placed at the rear. The display layer 9 is provided on the light source side A of the colored polycarbonate plate 11, and transmits light L1 from the light source 13, which is turned on when a warning is issued (when fuel is low).
The warning content is displayed brightly to alert crew member 1.
4. <Problems to be Solved by the Invention> However, in such a conventional display board 12, since the side surface 15 of the display board 12 opposite to the light source is a smooth surface, the external light L2 from the side B opposite to the light source is The display board 12 is reflected by the side surface 15 opposite to the light source.
The visibility of the display content on the display layer 9 may be reduced due to a decrease in the contrast of the display panel 12 or an external scene reflected on the display board 12. Further, the through holes L1 from the light source 13 were scattered by the display layer 9, which similarly reduced the visibility of the displayed contents. Therefore, as shown in FIGS. 13 and 14,
Incident angle of external light L2 and transmitted light L1 from light source 13
The outside light L2 is controlled by regulating the diffusion angle within a certain angle.
A generally known light-shielding film 16 consisting of a large number of small light-transmitting parts and non-light-transmitting parts [JP-A-57-189439, JP-A-51- 75456] may be used. This light-shielding film 16 was created by applying a liquid photosensitive resin containing particulate silica to form a non-transparent area on the transparent plate 17, masking it and exposing it to light, and removing the unexposed area corresponding to the transparent area. Thereafter, only the photosensitive resin 18, which becomes a non-light-transmitting part, is colored to become opaque as a cured "light-shielding film". However, due to the reflection of the external light L2 by the smooth side surface 15 opposite to the light source made of the transparent plate 17, the light-shielding film 16 itself cannot fully exert its function of regulating the incident and diffusion angle, and even when simply combined with the display board 12, the above-mentioned It was not enough to resolve the problem. This invention was made by focusing on such conventional technology, and uses a light-shielding film to clearly display the displayed content on the display layer without reducing the contrast due to external light or reflecting the external scenery. The purpose is to provide a display board that can be visually recognized. <Means for Solving the Problems> In order to achieve the above object, the present inventor conducted various experiments and research on display boards combined with light shielding films, and found that the side surface of the display board opposite to the light source was The present invention was completed based on the discovery that the original function of the light-shielding film can be exerted by providing an uneven surface. That is, the present invention provides a display board that includes at least a display layer that displays display content and that displays display content by transmitting light from a light source arranged at the rear, in which the display layer is located on the light source side or on the side opposite to the light source. A light-shielding film having a large number of fine light-transmitting parts and non-light-transmitting parts is disposed on at least one of the transparent substrates, and a transparent substrate having a finely uneven surface on the side opposite to the light source is provided at least on the side closest to the light source. <Function> Since the light-shielding film is provided on at least one of the light source side and the opposite side of the light source of the display layer, the light transmitted from the light source is restricted within a certain angle and is difficult to diffuse over a wide angle after passing through the display board. In addition, since at least a transparent substrate with a finely textured surface on the side opposite to the light source is provided on the side closest to the light source, external light is uniformly and finely dispersed on this finely textured surface. It is possible to prevent crowding and other problems. In addition, even if transmitted light is scattered on the display layer, the transmitted light scattered by this finely uneven surface is dispersed and scattered more uniformly and finely, so there is no problem in visual recognition, and the light shielding film's incident/diffusion angle regulating function It has no effect on itself. <Example> The present invention will be described below based on the drawings. still,
Descriptions that overlap with those of the prior art will be omitted, and common parts in the following description will be denoted by the same reference numerals. First Embodiment FIGS. 1 to 4 are diagrams of a display board 19 of a warning lamp (fuel alarm) showing an embodiment of the present invention. 20 is a colored polycarbonate plate as a "transparent substrate", with a thickness of 0.5 mm and total light transmittance.
58.3%, and one light source side A is provided with a display layer 21 printed with pictographs indicating warning content, and the other side opposite the light source 22 is a finely uneven surface. And this colored polycarbonate board 2
On the light source side A of 0, a light shielding film 23 made of liquid urethane-based photosensitive resin and having a thickness of 0.7 mm and a total light transmittance of 69.8% is bonded via a double-sided adhesive tape 24. Further, on the light source side A of this light shielding film 23, a colorless and transparent polycarbonate plate 26 with a thickness of 0.5 mm, which has lighting color pigment printing 25 applied on the side B opposite to the light source, is also bonded via double-sided adhesive tape 24. ing. In other words, in this display board 19 as a whole, the light shielding film 23 is replaced by the colored polycarbonate board 2.
0 and a colorless and transparent polycarbonate plate 26. This light-shielding film 23 has a honeycomb structure as shown in FIGS. 2 and 3, and has sufficient strength so that the image is not damaged when developing unexposed areas, and at the same time has high transparency. It is something. Furthermore, this light-shielding film 23 specifically includes a hexagonal light-transmitting part 27 that allows light to pass through, and partition walls of this light-transmitting part 27, which are dyed with black dye to become sufficiently opaque so as not to allow light to pass through. The non-transparent part 28 is connected to the non-transparent part 28. In this embodiment, the short axis d1 of the transparent part 27 is 270μ, the long axis d2 is 315μ, and the depth (thickness) h
is 700μ, the width l of the non-transparent part 27 is 50μ, and outside light L
2 and the incident/diffusion angle Θ of the transmitted light L1 is theoretically approximately
It was set at 42°. Regarding this incident/diffusion angle Θ, as already proposed by the present applicant, 24° < Θ < 54° is optimal.
The ratio of the diameter d of the inscribed circle of 1.2<d/l
<25 is optimal. Further, the colored polycarbonate plate 20 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 lighting color of the light source 29. In addition, colored polycarbonate board 2
When we investigated the relationship between the total light transmittance ratio of 0 and the contrast ratio, we found that the contrast ratio reaches its maximum value when the total light transmittance is around 60%, as shown in Figure 4. The colored polycarbonate board used this time has a total light transmittance ratio of 58.3%. The existence of a maximum value in the contrast ratio curve as described above is due to the fact that the reflectance rapidly increases in a quadratic curve as the total light transmittance ratio increases. The polycarbonate plate 26 closest to the light source side A is made of a colorless and transparent material in order not to reduce the light transmittance of the display panel 19 as a whole. In this embodiment, the display board 1 as described above is used.
9, the side surface 2 opposite to the light source of the colored polycarbonate board 20 constituting the side B closest to the light source of the display board 19
2 was provided with a finely textured surface, and the degree of the finely textured surface was varied to examine how the display layer 21 was viewed from the passenger 30.

[Table] In the experiment, 60 degree specular gloss G1 [6.7 of JISK5400-1979],
Relative gloss G2, which is the ratio of the 60 degree specular gloss G1 of the finely textured surface to the 60 degree specular gloss G1 of the untreated smooth surface expressed as a percentage, and the center line average roughness Ra [JISB0601
−1982]. Table 1 above shows the results. In addition, in this experiment, in order to investigate the incident/diffusion angle regulating function of the light shielding film 23 in the display panel 19, we investigated whether or not the display contents were reflected on the side window glass and front window glass located near the display panel 19. I tried it. In other words, the display content of the display layer 21 is reflected on the side window glass or the front window glass, which means that the light shielding film 23 is at least transparent L1.
This shows that the diffusion angle of is not regulated. According to Table 1, in Experimental Examples 1 to 4, the display was not reflected on the side window glass or the front window glass, and the anti-light source side surface 22, which is the surface of the display board 19 closest to the anti-light source side B, was specularly reflected. I was able to visually recognize the displayed content without any problems. However, in Reference Example 1, in which the center line average roughness Ra was intentionally made small, the side surface 22 opposite to the light source caused specular reflection on the display layer 2.
It was difficult to see the display contents in item 1. Similarly, in Reference Example 2 and Reference Example 3 in which the 60 degree specular gloss G1 and the relative gloss G2 are intentionally made small, the display layer 2
The content displayed in step 1 was reflected in the side window glass and front windshield of the person close to me. This is because, as described above, the incident/diffusion angle regulating function of the light-shielding film 23 is obstructed by the side surface 22 opposite to the light source and the display layer 21, and the transmitted light L1 from the light source 29 that contributes to displaying the display contents is wide angle. This means that it has spread. Therefore, as can be seen from Table 1 above, the appropriate range of the degree of fine unevenness is relative gloss G2 = 25 to 65% and center line average roughness Ra = 0.2 to 0.7μ. It can be said. Second Embodiment FIG. 5 is a diagram showing another embodiment of the present invention. The display board 31 in this embodiment has a specular gloss of 60 degrees on the side surface 22 of the colored polycarbonate board 20 that constitutes the side B opposite the light source of the display board 19 in the previous embodiment.
When G1 = 49%, relative gloss G2 = 41.3%, and center line average roughness Ra = 0.52, the light source side surface 3 of the colorless and transparent polycarbonate plate 26 that constitutes the light source side A
2 was made into a finely uneven surface having smaller irregularities than the finely uneven surface of the previous example.

[Table] Table 2 shows the results of examining how the displayed contents of the display layer 21 appeared by varying the degree of micro-irregularity of the polycarbonate plate 26. As can be seen from Table 2, in Experimental Examples 5 to 7, in which the light source side surface 32 was a very small uneven surface, the brightness of the display board 31 was uniform, and the peripheral part of the display board 31 was bright and visible. be able to. On the other hand, in Experimental Examples 8 and 9, in which the degree of unevenness was approximately the same as that of the finely uneven surface of the first embodiment, the light source 29 was
The central part of the display board 31 where is located can be particularly bright. In this way, by making the light source side surface 32 of the display board 31 a counter-light source side surface 32, that is, a finely uneven surface with smaller irregularities than the finely uneven surface, the transmitted light L1 from the light source 29 is uniformly dispersed and passed through the display board 31. As can be seen from Table 2, the degree of minute unevenness at that time is determined by the relative gloss level.
It can be said that G2≦18% and center line average roughness Ra≧0.95μ are appropriate. Third Embodiment FIG. 6 is a diagram showing still another embodiment of the present invention. In this example, the appearance of the display layer 21 of the display board 33 in which the surface 25a of the lighting color pigment print 25 of the display board 31 of Example 2 was made into a finely uneven surface was investigated. The experiment was conducted in the same way as Experiments 1 to 9 in the previous example, and there was no reflection on the side window glass or front window glass, no specular reflection, no uneven brightness, etc. As in the previous experiments 1 to 7, the display board 33 could be clearly seen. Fourth Embodiment FIG. 7 is a diagram showing still another embodiment of the present invention. In this embodiment, the display layer 21 of the display board 31 of the second embodiment is provided not on the colored polycarbonate board 20 but on the opposite light source side B of the lighting color pigment print 25 applied to the colorless and transparent polycarbonate board 26. I looked into how the display contents on board 34 looked.
Experiments similar to Experiments 1 to 9 of the previous example were conducted, and the visibility of the display board 34 was extremely good as in the previous example. Furthermore, this display board 3
The display contents of the display layer 21 of No. 4 are visible only when the light source 29 is turned on, and when the light source 29 is not turned on, the display contents of the display layer 21 are visible to the passenger 30.
It was also found that it exhibits the property of becoming invisible. Fifth Embodiment FIG. 8 is a diagram showing still another embodiment of the present invention. First, the configuration of the display board 36 will be explained.
is a colorless and transparent polycarbonate plate with a thickness of 0.5 mm.
The light source side 32 is a slightly uneven surface, and the side B opposite to the light source is inked with green fluorescent ink (manufactured by Dainippon Ink).
The lighting color pigment printing 25a is screen printed to a thickness of 10 μm. The finely uneven surface of the light source side surface 32 has a center line average roughness Ra = 1.21μ and a 60 degree specular gloss G1.
= 12.5%, relative gloss G2 to untreated smooth surface
= 7.4%. Furthermore, lighting color pigment printing 25a
Display layer 2 with a thickness of 10μ made of black opaque pigment on top.
1 is printed. 23 is a light-shielding film, in which a liquid urethane photosensitive resin (manufactured by Asahi Kasei) is passed through a negative film and irradiated with ultraviolet rays to harden the exposed areas, and after removing the unexposed areas with a 1wt% sodium borate aqueous solution, it is coated with a black disperse dye. The remaining portion was dyed to become opaque, forming a honeycomb structure as shown in FIG. The size of the transparent part 27 is
d1=270μ, d2=315μ, width l of non-transparent part 28
= 50μ, depth (thickness) h = 700μ. At this time, the diffusion angle Θ of the transmitted light L1 emitted from the light source 29 and passing through the display panel 36 was 42° in the horizontal direction and 48° in the vertical direction, and the total light transmittance was 69.8%. The light-shielding film 23 is adhered to a lighting color pigment print 25a and a black frame print 35, which will be described later, via a double-sided adhesive tape 24. Reference numeral 20 is a colored polycarbonate plate having a thickness of 0.5 mm, the side surface 22 opposite to the light source is a finely uneven surface, and the other surface is printed with an opaque black frame print 35. In addition, this colored polycarbonate board 2
The total light transmittance of 0 was 58.3%. Then, the degree of unevenness of the finely uneven surface formed on the side surface 22 opposite to the light source of the colored polycarbonate plate 20 was examined.
The same results as in Table 1 of the first example were shown. Therefore, even if a fluorescent dye is used for the lighting color pigment printing 25a, the unevenness of the colored polycarbonate plate 20 has a relative gloss level G2 of 25 to 65% and a center line average roughness Ra of 0.2 to 65%.
It has been found that 0.7 is particularly preferred. Conversely, when the side surface 22 opposite to the light source of the colored polycarbonate plate 20 is set to 60 degree specular gloss G1 = 49%, relative gloss G2 = 41.3%, and center line average roughness Ra = 0.52, the colorless and transparent polycarbonate plate 26 is When we examined the brightness of the display board 36 when the light source 29 was turned on by changing the unevenness of the light source side surface 32, we found that the relative glossiness G2≦15 was almost the same as in Table 2 of the second embodiment.
%, center line average roughness Ra≧1.1μ was found to be particularly preferable. When fluorescent paint is used, fluorescent paint has better translucency than other pigments, so
It seems that the unevenness must be made larger than in the previous example. Next, the conventional display board 12 shown in FIG.
The display board 36 of this embodiment, and this display board 36
Light is irradiated from an angle of 45 degrees to each of the display boards 36a with the lighting color pigment printing 25a of ordinary color that does not contain fluorescent paint, and each display board 12,
Let E1 be the output voltage of the phototube installed in the photoreceiver installed in the direction perpendicular to 36 and 36a,
Next, an incandescent light bulb (3.5W, 12V) placed 5 mm above each display board 12, 36, 36a is turned on, and the output voltage is set as E2, and the ratio between the two is C=E2/
E1 is the contrast ratio [see Figure 9]. 9th
As is clear from the figure, the display board 36 using fluorescent paint was able to obtain a high contrast ratio.
Then, when the display board 36 of this embodiment was attached to the warning lamp part of a car and the light source 29 was repeatedly turned on and off under conditions where direct sunlight was incident on the display board 36 during the daytime, the light source 29 was turned on and off. can be easily identified, and it was confirmed that there is no need for a protrusion such as a hood to shade the sun. In addition, in the above description, the display boards 19, 31, 3 of automobile warning lamps are provided with the display layer 21 by printing.
33, 34, and 36, but the present invention is not limited thereto, and the present invention is applicable not only to automobile speedometers, tachometers, odometers, trip meters, etc. provided with liquid crystal display layers, but also to airplanes,
This also applies to various display boards used for instruments such as ships, audio equipment, research equipment, etc. <Effects> Since the display board according to the present invention has the content as described above, the original function of the transparent board is to regulate the incident angle of external light and to regulate the diffusion angle of transmitted light from the light source within a certain range. Therefore, when used in warning lamps on automobile instrument panels, etc., it can more reliably prevent the contrast of the display board from being reduced due to external light and the reflection of external scenery on the display board. This has the effect of greatly improving the visibility of the display board. Further, according to the embodiment of the present invention, since the side surface of the light source of the display board is formed into a finely uneven surface, the brightness of the display board can be made uniform and the visibility of the display board can be further improved. By providing the pigment printing on the side opposite to the light source, there is also the effect that the display layer can be made visible only when the light source is on and invisible when the light source is not on. Therefore, the display board according to the present invention is preferable from the standpoint of safety in the event of a collision, since it is not necessary to provide a hood-like protrusion to block external light or prevent reflection on the outside. There are also contingency effects.

[Brief explanation of drawings]

FIG. 1 is an enlarged sectional view of a display board showing a first embodiment of the present invention, FIG. 2 is an enlarged plan view showing a light-shielding film in FIG. 1, and FIG. 4 is a graph showing the relationship between the total light transmittance ratio and the contrast ratio of a colored polycarbonate board. FIG. 5 is an enlarged view of a display board corresponding to FIG. 1 showing a second embodiment of the present invention. 6 is an enlarged sectional view of a display board equivalent to FIG. 1 showing a third embodiment of the present invention, and FIG. 7 is an enlarged view of a display board equivalent to FIG. 1 showing a fourth embodiment of the invention. 8 is an enlarged sectional view of a display board corresponding to FIG. 1 showing a fifth embodiment of the present invention; FIG. 9 is a graph showing contrast ratio;
FIG. 10 is a perspective view of an instrument panel showing a conventional example of the present invention, FIG. 11 is an enlarged plan view showing a warning lamp in the instrument panel shown in FIG.
1 is an enlarged sectional view taken along the arrow line XII--XII in FIG. 1, FIG. 13 is an enlarged plan view of a light-shielding film showing a conventional structure of the present invention, and FIG. 14 is an enlarged sectional view taken along the arrow line ``-'' in FIG. 13. . 9,21...Display layer, 11,20...Colored polycarbonate plate (transparent substrate), 1219,31,
33, 34, 36... display board, 13, 29... light source, 15, 22... side opposite to light source (finely uneven surface),
16, 23... Light shielding film, 26... Colorless transparent polycarbonate plate (transparent substrate), A... Light source side, B
...Anti-light source side, L1... Light transmitted from the light source, L2
...External light, Θ...Incidence/diffusion angle, d1...Breadth axis of the transparent part, d2...Long axis of the transparent part, d...Aperture or diameter of the inscribed circle of the transparent part, h... Depth of transparent part,
l... Width of non-transparent part, G1... Specular gloss, G2
... Relative glossiness, Ra ... Center line average roughness.

Claims (1)

[Scope of Claims] 1. In a display board that includes at least a display layer that displays display content and that displays display content by transmitting light from a light source disposed at the rear, the display layer is located on the light source side or opposite to the light source. A light-shielding film having a large number of fine light-transmitting parts and non-light-transmitting parts is arranged on at least one of the sides, and a transparent substrate having a finely uneven surface on the side opposite to the light source is provided at least on the side closest to the light source. A display board.