JPS6234103A - Environmental resistant structure of phosphate glass - Google Patents

Abstract

PURPOSE:To prevent deterioration in the characteristics of an optical system or the damage of the system in an environment at high temp. and humidity by interposing a prescribed protective film between phosphate glass and an optical element before adhesion. CONSTITUTION:SiO25 is vapor-deposited on the face of phosphate glass 1 to be adhered to a phase plate 2 so as to prevent the diffusion of chemical substances such as phosphoric acid deposited on the face from the glass. The glass 1 is adhered to the phase plate 2 with an adhesive 3 with the SiO25 in-between. Even when the resulting optical system contg. the phosphate glass 1 is used in an environment at high temp. and humidity or allowed to stand in the environment, the adhesive layer is not corroded and the stable characteristics can be maintained. When an antireflection film 4 of SiO2 or the like is formed on the unadhered face of the glass 1 by vapor deposition, the film 4 is also advantageous to adhesion to other optical element. Al2O3, MgF2, TiO2 or ZrO2 may be used in place of the SiO25 forming a protective film.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an environmental protection structure of phosphate glass used as an infrared absorption filter in various optical systems.

(Prior art) Phosphate-based glass is commonly used as an infrared absorption filter used in optical systems such as imaging systems of conventional video cameras, but this type of glass is not suitable for use in high-humidity environments. There is a problem in that various constituent substances such as phosphoric acid precipitate due to the action of moisture, causing not only "burning" of the glass but also chemical change noises in other surrounding materials.

To deal with this problem, acid-based glass is usually used as shown in FIG. 2, as shown in FIG. Protect the phosphoric acid glass 1 by attaching members such as optical elements such as prisms, filters, phase plates, or lenses that are stable in the surrounding general environment via adhesives 3 such as ultraviolet curing resins. If necessary, antireflection coatings 4, 4 were attached to the non-adhesive surface of the protective layer.

However, even if conventional protection measures such as those described above are used, when exposed to a high temperature and high humidity environment, not only will the adhesion surface become cloudy due to the effects of precipitated substances from the phosphate glass, but also the adhesive strength with the protective layer will deteriorate. There were defects such as a decrease in phosphoric acid glass and the protective layer peeling off.

(Objective of the Invention) The present invention has been made in order to eliminate the deficiencies in the environmental resistance of optical systems using conventional phosphate glass as described above, and by adding a simple process to phosphate glass. The purpose of the present invention is to provide an environmentally resistant structure for phosphoric acid glass that can completely prevent characteristic deterioration or damage of optical systems in high-temperature, high-humidity environments without necessarily adopting a sandwich structure. do.

(Summary of the Invention) In order to achieve the above objects, the environmental resistant structure of the phosphate glass according to the present invention has the following configuration. In other words, phosphoric acid glass and other optical elements such as phase waves, filters, prisms, or lenses? When bonding, a protective film is attached to the bonding surface of the phosphate glass to prevent chemical substances precipitated from the phosphate glass from penetrating into the contact layer, and the phase plate or prism is bonded through this protective film. etc. are glued together.

(Embodiments of the Invention) The present invention will be described in detail below based on embodiments shown in detail.

FIG. 1 is a sectional view showing a basic embodiment 2 of the environmentally resistant structure of phosphate glass according to the present invention.

In this figure, the bonding surface between phosphoric acid glass 1 and other optical elements 1 such as phase plate 2 is shown.

8 as a protective substance to prevent the diffusion of chemical substances such as phosphoric acid precipitated from the glass on the adhesive surface of the phosphoric acid glass.
102 layer 5 is deposited, and the phase plate 2 is bonded with adhesive 3 through this deposited protective layer.

By doing so, even if the optical system contained in the phosphoric acid glass 1 is used in a high temperature and high humidity environment or left in such an environment, the adhesive layer will not be damaged and stable characteristics will be maintained. can be maintained.

However, if 5iOz, AIzOa, MgFz, etc. are simply deposited on the non-adhesive surface of the phosphate glass 1 as an anti-reflection film 4, this will also have the function of a protective film for that surface. Since it is not necessarily necessary to sandwich the optical element between other optical elements to form a sandwich structure, this is advantageous in terms of simplifying, downsizing, and lowering the cost of the entire optical system.

Furthermore, the material constituting the entire protective layer 5 is not necessarily 5i.
There is no need to limit it to At 2031MgFz,
It is possible to select and use Ti0z, Zr0z, etc. as appropriate.

(Effects of the Invention) Since the present invention is constructed as described above, it is possible to create an optical system that cuts infrared rays using phosphate glass by simply adding all the simple steps or by adding an antireflection film. By simply applying the adhesion process to the surface of the phosphate glass, it is possible to prevent the chemical substances precipitated from the phosphate glass from penetrating into the adhesive layer of the optical element, thereby improving the environmental resistance of such optical systems. This has a remarkable effect not only in improving the optical properties of the optical system and preventing breakage while maintaining its optical properties, but also in simplifying the optical system and reducing its cost.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing a basic embodiment of the environmentally resistant structure of phosphate glass according to the present invention, and FIG. 2 is a sectional view showing a conventional protective structure of phosphate glass. 1... Phosphate glass, 2...Mountain...
...Optical elements made of materials other than phosphate glass. 3...Adhesive layer.

Claims (2)

[Claims] (1) A protective film that prevents chemical substances such as phosphoric acid deposited from the phosphoric acid glass from penetrating into the adhesive layer on the adhesive surface of the phosphoric acid glass when bonding the phosphoric acid glass to other optical elements. 1. An environment-resistant structure of phosphoric acid glass, characterized in that the phosphoric acid glass is adhered to other optical elements via the protective film. (2) The protective film is OiO_2, Al_2O_3, Mg
The environment-resistant structure of phosphate-based glass according to claim (1), characterized in that it is a single layer selected from F_2, TiO_2, or ZrO_2, or a multilayer film made by laminating these materials.