JPH0380313B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a reflected light out-of-field removal screen device most suitable for use in front of a cathode ray tube in a word processor, computer, or the like.

As shown in Fig. 1, light from indoor lighting and other sources reaches the surface of a display cathode ray tube 1 of a word processor, computer, etc., and is reflected there and reaches the operator's eyes E as shown by symbol R. There are many things. This is undesirable for the operator because the reflected light makes it difficult to see the cathode ray tube surface. In order to solve this problem, an anti-reflection screen 2 was installed in front of the cathode ray tube 1.
is being installed.

By the way, as shown in FIG. 2a, the anti-reflection screen 2 has numerous minute transverse protrusions 3 having a sawtooth cross section with reflective slopes 4 on the front surface, and parallel to the reflective slopes 4 on the rear surface. The present applicant previously proposed a translucent Fresnel screen equipped with numerous ridges with slopes. The reflective slopes 4 of each protrusion 3 on the front side of this Fresnel screen 2 face obliquely downward as shown in the figure, and therefore, light 5a and 6a from illumination lights etc. are reflected by the reflective slopes 4 as shown by 5b and 6b. It is reflected downward and guided out of the field of view of the operator's eye E. On the other hand, the light that enters the inside of the Fresnel screen from the front surface of the Fresnel screen 2 is reflected by the rear surface and travels downward as light parallel to the front reflected light 6b, as shown by reference numeral 6b' in FIG. is guided out of the field of view of the operator's eye E.

In this way, the Fresnel screen 2 is useful in that it reflects light from above downward and prevents glare, but the keyboard 7, etc., which is installed almost horizontally in front of it, is reflected on the screen surface. This is undesirable because the reflected image enters the operator's eye as shown at 8 in FIG. 2a. In addition, the reflected image is
It is also caused by light that once enters the interior of the Fresnel screen 2, is reflected from the rear surface, and then heads forward again. Since the keyboard 7 is generally painted in a whitish color, the operator sees a whitish image of the keyboard reflected on the screen surface, making it difficult to see the cathode ray tube surface.

The present invention has been developed in view of the above-mentioned problems, and is an inexpensive method of reflecting light outside the field of view that prevents both light from above and light from below, such as from a keyboard, from being reflected towards the operator's eyes. A removal screen device is provided.

Next, to explain an embodiment of the present invention, in FIG.
It consists of a translucent Fresnel screen with numerous similar protrusions on the front and rear. The lateral protrusions 13 are parallel to each other, and their reflective slopes 14 face obliquely upward, opposite to the reflective slope 4 in the case of FIG. 2a. Therefore, the light from the keyboard 17 etc. is typically 15a, 15b.
As is clear from the figure, there is no reflection on the surface of the Fresnel screen 12 in the direction toward the operator's eyes E, and the keyboard 17 and the like are not reflected on the Fresnel screen surface.

At the upper end of the front surface of the translucent Fresnel screen 12, a light shielding section 16 extending in the shape of an eave is provided. It is preferable that the light shielding part 16 is extended and provided on both sides of the Fresnel screen 12 as shown by 16'.

The projecting dimensions of the light shielding part 16 are set so that light from an illumination lamp or the like coming from diagonally above is not reflected toward the operator's eyes E. For example, when the incident light 18a that reaches the reflective slope 14 at the lowermost part of the front surface of the Fresnel screen 12 from diagonally above becomes reflected light 18b and reaches the operator's eye E, the light shielding part 16 is adjusted to the extent that the incident light 18a can be blocked. Determine the overhang dimensions. In this way, the incident light 1
Since the reflected lights 19b and 20b of the incident lights 19a and 20a that reach the lowermost reflective surface 14 with a gentler slope than 8a all head upwards from the eye E, the screen 12
Objects such as illumination lights diagonally above will not be visible.

In addition, a reflective surface 14 located above the lowest reflective surface
The light 21a incident obliquely from above is reflected obliquely upward as shown by 21b, and in any case it does not go toward the eye E. Furthermore, since all the light having a steeper slope than the incident light 18a is blocked by the light shielding part 16 and does not reach the surface of the screen 12, there is no reflected light due to it.

In this way, according to the present invention, light from diagonally above as well as light from diagonally below can be directed to the operator's eyes.
The display on the cathode ray tube surface behind the Fresnel screen 12 can be seen through the Fresnel screen 12 without any reflection.

The same thing can be said about the reflected light that enters the inside of the Fresnel screen 12, is reflected at the rear surface, and goes forward again, but the Fresnel screen 1
The protrusion on the rear surface of No. 2 may be omitted and the rear surface may be simply a flat surface.

As is clear from FIG. 3, the angle θ formed by the opposite slope 14 of the Fresnel screen 12 used in the present invention with respect to the vertical direction (plate surface direction) must be quite large. Therefore, the protrusion dimension (height) of the protrusion 13 becomes relatively large. However, the larger the angle θ, the more difficult it becomes to manufacture a Fresnel plate.

To solve this problem, it is preferable to install the Fresnel screen 12 at an angle so that it is completely retracted to the top, as shown in FIGS. 4 and 5. For this purpose, a bottom plate 22 is placed below the light shielding part 16.
are provided, and these are used as the left and right side plates of the light shielding part 1.
6', and a Fresnel screen 12 is attached diagonally to the light shielding part 16'. By doing this, even if the angle θ of the slope 14 of the Fresnel screen 12 is small, the angle that the slope 14 makes with respect to the vertical direction can be made relatively large, and the Fresnel screen itself can be manufactured easily. . On the other hand, it is preferable from an ergonomic point of view to install the Fresnel screen 12 diagonally.

The inside of the light-shielding parts 16 and 16' is sufficiently effective without any treatment, but if you apply a black matte coating or cover it with black velvet-like cloth, the Fresnel screen surface will be even more effective. can eliminate reflections.

In the embodiment described above, the protrusions 13 of the Fresnel screen are provided parallel to the horizontal direction, but the arrangement of the protrusions 13 is, for example, as shown in FIG. It may be formed by a row of ridges or, as shown in FIG. 7, by a row of diagonally oriented protrusions. In any case, the protrusions 13 may be provided in a direction that has a lateral component. In this way, the forward reflection of light on the rear surface of the Fresnel screen and the forward reflection of light on the cathode ray tube surface after passing through the Fresnel screen are doubly weakened by passing through the Fresnel screen.

As described above, according to the present invention, it is possible to obtain a screen device that is completely non-reflective by simply arranging a commonly available Fresnel plate in a specific direction and providing a light shielding portion at its upper end.

[Brief explanation of drawings]

Figure 1 shows how reflected light enters the eye, Figure 2
Figure a is an explanatory diagram of a conventional anti-reflection screen;
Fig. b is a partially enlarged view thereof, Fig. 3 is a principle diagram of the reflected light out-of-field removal screen device according to the present invention, Fig. 4 is a perspective view of the modified embodiment, Fig. 5 is a longitudinal sectional view of the same,
Figures 6 and 7 are diagrams showing deformed shapes of the protrusions. 12...Fresnel screen, 13...projection,
14... Reflective slope, 16, 16'... Light shielding part, 1
7...keyboard, 22...bottom plate.

Claims (1)

[Scope of Claims] 1. A translucent Fresnel screen having countless small lateral protrusions with a serrated cross section on the front surface having reflective slopes facing diagonally upward is arranged in the vertical direction, and the front surface of the Fresnel screen is A screen device for removing reflected light outside the field of view, which is provided with a light shielding part that extends like a canopy at the upper end. 2. The Fresnel screen as set forth in claim 1, wherein the Fresnel screen is inclined so that the front surface of the translucent Fresnel screen is completely retreated to the top thereof, and the light shielding portions are provided extending to both sides of the Fresnel screen. Screen device for removing reflected light outside the field of view.