JPH0447622Y2 - - Google Patents

Description

[Detailed description of the invention] (Industrial application field) This invention relates to the improvement of reflective dials used in surveying instruments, etc., and in particular to the improvement of horizontal protractor dials for leveling instruments.

(Prior art) Reflective dials used in surveying instruments, etc. are generally made of a light-transmissive glass plate with, for example, a linear portion that hardly reflects visible light and a background portion that reflects well. A system as shown in Fig. 2 is in practical use. That is, the surface of the glass plate 1 is coated with highly reflective silver or aluminum by vapor deposition or the like, and then photo-etched into a predetermined pattern, and then black paint is applied to form the etched portions into black scales. The reference numeral 2 in the figure is a coated silver layer, 3 is a black painted part, and the distance between the silver layers 2 becomes a scale line. In this configuration, bubbles 4 are likely to occur near the gap, and especially large bubbles 4' as shown in the corner of the gap
is formed, making the scale lines unclear.

In order to eliminate this drawback, as shown in Figure 3, a glass plate 1 is coated with a chromium oxide layer 5 that has a low reflectance, that is, looks black, without using black paint, and then a chromium 6 layer with a high reflectance is applied. A coating method has been proposed. According to such a configuration, chromium oxide and chromium have high adhesion to glass, so
Although a scale plate with excellent durability can be obtained, it has conventionally been desired to make the scale lines even clearer.

(Problem that the invention aims to solve) This invention was made in response to such a conventional request, and was designed to make the scale lines of surveying instruments, etc. clearer than the conventional ones. ,
The purpose is to provide a reflective scale that can brighten the optical system.

(Means for solving the problem) As shown in the schematic diagram in FIG. The scale with a predetermined pattern is formed by photo-etching. The scale lines are made clear by coating aluminum 8 thereon to form a highly reflective layer. Then, a black paint film 9 is applied as a protective film or chromium 9 is coated.

(Function) Since the conventional glass/chromium reflective layer 6 shown in Figure 3 has been improved to the glass/aluminum reflective layer 8 shown in Figure 1, the reflectance for visible light at about 550 mm is approximately 60% of that shown in Figure 3. It is improved from ~65% to about 80-90% in the one in FIG. On the other hand, at the scale line, since the chromium oxide layer 5 is backed by the chromium layer 7, the reflectance is the lowest, and a reflectance of about 4% is obtained. In conventional products, adhesion is good when using chromium oxide alone, but the light is not blocked sufficiently, resulting in a light brown color, and reflection is not reduced. In addition, with a chromium oxide layer directly backed by an aluminum layer, the reflectance is as high as about 20%, making the scale unclear.

The back side of the scale plate may be painted black, but if chrome is vapor-deposited, the protective film will be highly durable and will not be affected by temperature or humidity. It is possible to coat it with a protective film of chromium.

(Example) Chromium oxide 5 with a thickness of 1000 Å is coated on the back surface of the glass plate 1 for 60 seconds by vacuum deposition at 300°C and 3 × 10 ^-5 Torr, and similarly, chromium oxide 5 with a thickness of 1000 Å is coated on the back surface of the glass plate 1. 7 was coated, and this was etched using a known photolithography method to form graduations. Aluminum 8 was deposited to a thickness of 1000 Å on this at room temperature. Furthermore, 80 at 200℃
A protective film consisting of a chromium layer 9 of 1500 Å was applied by performing the same vacuum deposition over a period of seconds.

Its cross section is as shown in the schematic diagram in Figure 1, where 1 is a glass plate, 5 is a chromium oxide layer, 7 is a chromium layer backed by this, and 8 is an aluminum layer, which is the glass plate 1. Shows high reflectivity between Reference numeral 9 is a chromium layer that protects these.

(Effects of the invention) As explained above, according to the invention, the outline of the scale lines is clearer than that of the conventional one, the contrast between the scale lines and the background is higher, and optical The system becomes brighter and can be applied to surveying instruments to obtain a reflective dial that is easy to observe.

[Brief explanation of the drawing]

Fig. 1 is an enlarged schematic sectional view of one embodiment of the reflective scale plate of the present invention, Fig. 2 is an enlarged sectional view of a conventional reflective scale plate, and Fig. 3 is an enlarged view of an improved version of the one in Fig. 2. It is a cross-sectional schematic diagram. 1...Glass plate, 2...Silver layer, 3...Black paint film, 4...Bubbles, 5...Chromium oxide layer, 6,7...
...Chromium layer, 8...Aluminum layer, 9...Protective film.

Claims (1)

[Scope of utility model registration request] On the back side of the transparent plate, a scale pattern consisting of a coated chromium oxide layer and a chromium layer is formed in order from the transparent plate side, and the entire back side including the scale pattern is covered with an aluminum layer and a protective film consisting of a chromium layer or a paint film. A reflective scale plate characterized by being covered by.