JPH0565098U - Electroluminescence display - Google Patents

Abstract

(57) [Summary] [Purpose] To improve the contrast. [Structure] Ribbon-shaped lattice elements 16a are sequentially arranged so as to face each other to form a striped lattice, and the outer periphery of the lattice is integrally integrated as a light-shielding mask 16 to form the light-shielding mask 16. Is faced to the front. Ambient light larger than the angle α (FIG. 1B) does not reach the display surface, and the contrast is improved accordingly.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an electroluminescence display device that displays characters, figures, etc. using an electroluminescence (EL) plate as a surface light source.

[0002]

[Prior Art]

 2A and 2B show a conventional electroluminescence display device. A is an exploded perspective view thereof, and B is a sectional view. A drive unit 12 for applying a light emitting electric field is attached to the EL plate 11, and a cord 13 for connecting to a power source is led out from the drive unit 12. The display plate 14 is in contact with the light emitting surface of the EL plate 11. In this example, the EL plate 11 and the display plate 14 are also rectangular plates of the same size. The display plate 14 is either a transparent plate having an opaque display pattern 15 written on it, or an opaque plate having a transparent display pattern portion. Such an EL display has an advantage that it can have a large display area, is light and thin, and has flexibility.

[0003]

[Problems to be solved by the device]

 However, the EL plate 11 has not been used as expected because of a slight lack of brightness as a display device. In particular, the display function of an EL display device under direct sunlight deteriorates due to lack of brightness. For this reason, it is currently limited mainly to use in dark places or in the nighttime. However, the ideal display condition is that it can be used day or night and in any environment.

[0004]

[Means for Solving the Problems]

 According to this invention, the striped grid type light shielding mask or the grid-shaped lattice type light shielding mask having a thickness is provided on the entire surface of the EL display.

[0005]

[Action]

 This light-shielding mask reduces the amount of ambient light that illuminates the display surface more than before, and there is a large difference between the amount of light that passes through the EL plate and the amount of light that does not pass through the EL plate. Therefore, the display contrast is improved and the display pattern is easily recognized.

[0006]

【Example】

 Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows an embodiment of the present invention, in which parts corresponding to those in FIG. In this embodiment, a striped grid type light shielding mask 16 having a thickness is attached to the front surface of the EL display, that is, the surface of the display plate 14 opposite to the EL plate 11. That is, the plurality of ribbon-shaped lattice elements 16a are opposed to each other and are arranged at regular intervals, and the lattice elements 16a are contacted with the display plate 14 so that the width direction thereof is perpendicular to the display plate 14, that is, the front-back direction. .. Both ends of each of the lattice elements 16a are connected by a connecting plate 17, and a mounting collar 18 is attached to the outer periphery of the striped lattice. The lattice element 16a, the connecting plate 17, and the collar 18 are integrally formed as a molded product of, for example, a black synthetic resin material to obtain the light shielding mask 16. Alternatively, the lattice element 16a is a thin metal plate and is attached to the frame body forming the collar 18. In this example, the longitudinal direction of the lattice element 16a is aligned with the longitudinal direction of the display plate 14. As a matter of course, the lattice-shaped portion of the light shielding mask 16 faces the front surface of the display plate 14.

According to this configuration, the disturbance light 21 that obliquely enters the display plate 14 is blocked by the light shielding plate 16 and reaches the display plate 14 when the incident angle (angle with respect to the normal line of the display plate 14) is large. do not do. That is, in the vertical cross section of the shading plate 16, the disturbance light 21 having an incident angle larger than the angle α of the line connecting the front edge of one grating element 16a and the rear edge of the adjacent grating 16a with respect to the normal to the display plate is displayed. Do not reach the board. Similarly, the ambient light incident on the display plate 14 from diagonally below does not enter the display plate 14 if the incident angle is α or more. Therefore, when this display is viewed, the amount of ambient light reflected by the display plate 14 is smaller than that without the light-shielding mask 16, and the display contrast is improved. Therefore, the display can be viewed well even under the sunlight outside.

Although the viewing angle β at which the display can be viewed is limited by the light-shielding mask 16, for example, when this display is attached to the back of the vehicle and a person riding in a vehicle behind the vehicle sees it. As described above, when the viewing direction of the display is almost always constant, it suffices that the direction be within the viewing angle β, which is effective as such a display.

Next, the relationship between the viewing angle β and the minimum value α of the disturbance light blocking angle will be described. Assuming that the thickness of the light-shielding mask 16 (the width of the ribbon-shaped lattice element 16a, hereinafter referred to as the lattice thickness) is A and the spacing between the lattice elements 16a is 2B, α = arctan (2B / A). (1) β = 2 · arctan (B / A) ········ (2)

Here, the light blocking angle α required to obtain the viewing angle β = 45 ° is calculated. From the equation (2), B / A = tan (β / 2) = tan (45 ° / 2) = 0.414 is derived. Therefore, from the formula (1), α = arctan (2B / A) = arctan (2 × 0.414) = 39.6 °. This means that with a light-shielding mask with a viewing angle β = 45 °, ambient light with an incident angle of 39.6 ° or more is shielded. Further, by the same calculation, if the light blocking angle α 1 is set to 45 °, the viewing angle can be increased to β = 53 °. That is, since 2B / A = tan (45 °) = 1 is derived from the equation (1), β = 2 · arctan (B / A) = 2 · arctan (0.5 ) = 53 °.

The light-shielding angle α and the viewing angle β are uniquely determined only by the ratio of the grating thickness A and the grating interval 2B, and do not depend on the actual dimensions of the grating thickness A and the grating interval 2B. It is considered that these actual size methods mainly depend on the size of the display character or the display pattern on the display board 14. As a general rule, when the size of the display character or display pattern is small, both the thickness A of the grid and the grid spacing 2B are small, and when the former is large, the latter is also large. However, it is needless to say that the thickness A of the lattice and the lattice spacing 2B may be small even when the displayed characters and the display pattern are large. The ratio 2 / (2B) of the thickness A of the lattice to the lattice spacing 2B is 0.5 to 1.5, preferably 1. Also, for example, A = 2B = 5 mm.

As the light-shielding mask 16, it is possible to use a grid-shaped light-shielding mask having a grid pattern as shown in FIG. 2C. This is a device in which the lateral grid element and the vertical grid element are orthogonal to each other, and the light shielding effect is increased. When a grid-shaped light-shielding mask was used, a good display was obtained when the viewing angle was 45 ° or less. When the display panel 14 is long under the sun's rays outdoors, a striped grid type light-shielding mask in which the longitudinal direction of the grid elements coincides with the longitudinal direction of the display panel 14 is preferable so that the entire surface can be easily seen.

[0013]

[Effect of the device]

 As described above, according to the present invention, since the display surface is provided with the striped grid type light shielding mask or the grid-shaped lattice type light shielding mask, a part of the disturbance light reaching the display surface is shielded and the display plate is blocked. The ratio of the amount of light entering the eyes from the transmitted light portion and the non-transmitted light portion 14 becomes large, the display contrast becomes large, and the EL display becomes easy to see even in the daytime when there are many sun rays.

[Brief description of drawings]

FIG. 1A is an exploded perspective view of an electroluminescent display device according to the present invention, and FIG. 1B is a cross-sectional view showing an enlarged part of a vertical cross-sectional view of the display device.

FIG. 2A is an exploded perspective view showing an electroluminescence display device according to the prior art, B is a vertical sectional view of the display device, and C is a perspective view showing another example of a light-shielding mask used in the display device of the present invention. It is a figure.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Sadaji Hasegawa 1387 Tobuki-cho, Hachioji-shi, Tokyo Tokyo Cosmos Electric Co., Ltd.

Claims (1)

[Scope of utility model registration request] 1. An electroluminescent display device, characterized in that a lattice type light shielding mask having a thickness is provided on the front surface.