JPH0535362Y2 - - Google Patents

Description

[Detailed explanation of the idea] [Industrial application field] The present invention relates to a bonding layer of an optical element.

[Conventional technology]

In the past, for example, the patent application submitted by the applicant in 1982-
In the strabismus optical system (visual field direction conversion optical system) of a rigid endoscope described in the specification of No. 219840, as shown in FIG. 9A, the prisms 2 and 3 are bonded together with an adhesive, and 4 and prisms 2 and 3 to achieve reflection and transmission. Note that 1 is a concave lens.

[Problem that the invention attempts to solve]

However, in an endoscope, the prisms 2 and 3 are small and their bonding surfaces are extremely small, so the adhesive layer 4 becomes thin. As shown in FIG. 9B, there was a problem in that ghost rays leaked and the reflection and transmission characteristics were not constant. Another problem is that because the thickness of the adhesive layer 4 is thin (shorter than the coherence distance), light beams reflected on the first and second surfaces of the adhesive layer 4 interfere with each other, resulting in interference fringes. It was hot.

In view of the above-mentioned problems, the present invention aims to provide a bonding layer for an optical element that can maintain constant reflection and transmission characteristics at the bonding surface and prevent the generation of interference fringes.

[Means and actions for solving problems]

The bonding layer of the optical element according to the present invention includes a vapor deposited layer having a thickness of 1.5 times or more of the incident wavelength formed on a region other than the effective diameter of the transmission surface of the optical element or the total reflection surface, and a vapor deposited layer having a thickness of 1.5 times or more of the incident wavelength formed on the area other than the effective diameter of the transmission surface of the optical element or the total reflection surface. The thickness of the vapor deposited layer 12 is sufficient to prevent the leakage of ghost rays and the generation of interference fringes due to the adhesive layer formed over the entire surface and bonding the surface and the vapor deposited layer to other members. It is designed so that it can have a certain thickness.

〔Example〕

Hereinafter, the present invention will be explained in detail based on an illustrated embodiment.

In FIG. 1, reference numeral 11 denotes an optical element, 12 a vapor deposited layer having a thickness d equal to or more than 1.5 times the incident wavelength formed in a region other than the effective diameter of the transmission surface 11a of the optical element 11, and 13 a vapor deposited layer of the optical element 11. An adhesive layer formed over the entire transmission surface 11a to join the transmission surface 11a and the vapor deposition layer 12 to other members 14,
2 and the adhesive layer 13 constitute a bonding layer 15.

The bonding layer according to the present invention is constructed as described above, and since the thickness d of the vapor-deposited material 12 is at least 1.5 times the incident wavelength, the thickness of the bonding layer 15 is greater than that, and as a result, ghost rays are transmitted to the bonding layer. Since the ghost rays cannot pass through 15 and leakage is reliably prevented, the reflection and transmission characteristics at the bonded surface are kept constant. Also, for the same reason, the thickness of the bonding layer 15 is longer than the coherence distance, so the first layer of the bonding layer 15 is
No interference occurs between the light beams reflected by the surface and the second surface, and interference fringes are prevented from occurring at the bonded surface.

Note that the vapor deposition material 12 may be transparent or opaque.
Further, the shape of the vapor deposited layer 12 may be circular, square, or irregular. Further, the vapor deposition layer 12 may have a multilayer structure. Further, the vapor deposition layer 12 may be provided at a plurality of locations. Moreover, the optical element 11, the adhesive layer 13, the vapor deposition layer 1
The refractive index of bonding layer 1 is set to be smaller in order.
If 5 is used only as a total reflection surface, a vapor deposited layer 12 may be formed within the effective diameter.

FIG. 2 shows a first application example, in which the bonding layer 15 of the present invention is applied to prisms 16 and 1 of an optical system for oblique viewing of an endoscope.
7, and the bonding layer 15 is used for transmission and reflection. That is, it is designed to prevent interference fringes from occurring at the bonded surface and to maintain constant total reflection characteristics.

FIG. 3 shows a second application example, in which the bonding layer 15 of the present invention is applied to fixing a reflecting prism 18 to a lens frame 19, and the total reflection characteristics are kept constant. .

4A and 4B show a third application example, in which the bonding layer 15 of the present invention is applied to fixing a single fiber 20 to a lens frame 21 in an endoscope,
The total reflection characteristic is kept constant due to the difference in refractive index between the single fiber 20 and the adhesive layer 13.

Figure 5 shows the fourth application example, which is a color TV
The proposed bonding layer 15 is applied to bond each prism 22, 23, 24 in a three-color separation prism used for, etc., and the bonding layer 15 maintains constant total reflection characteristics at the bonded surface and generates interference fringes. This is to prevent

FIG. 6 shows a fifth application example, in which the bonding layer 15 of the present invention is applied to the bonding of prisms 26 and 27 of the visual field direction conversion optical system of an endoscope having a fixed image pickup element 25. This is to maintain constant total reflection and transmission characteristics and to prevent interference fringes from occurring.

FIG. 7 shows a sixth application example, in which the proposed bonding layer 15 is applied to bonding lenses 28 and 29 in a cemented lens, and is designed to suppress the occurrence of interference fringes at the bonded surface. be.

FIG. 8 shows a seventh application example, which is a half mirror with glass blocks 30,
The bonding layer 15 of the present invention is applied to the bonding of No. 31, which prevents changes in the characteristics of the half mirror due to variations in the thickness of the adhesive layer and keeps them constant, and also prevents the occurrence of interference fringes on the bonding surface. This is how it was done.

[Effect of idea]

As described above, the bonding layer of the optical element according to the present invention has the practically important advantage that the reflection and transmission characteristics at the bonding surface are constant and the generation of interference fringes is prevented.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of an embodiment of the bonding layer of an optical element according to the present invention, FIGS. 2 to 6 are sectional views of first to fifth application examples, respectively, and FIG. 7 is a perspective view of a sixth application example. 8 are a sectional view of the seventh application example, and FIGS. 9A and 9B are a sectional view and an enlarged sectional view of the main part of the conventional example, respectively. 1... Optical element, 11a... Transmissive surface, 12...
Vapor deposition layer, 13... adhesive layer, 14... other members,
15... Bonding layer.

Claims (1)

[Scope of utility model registration request] A vapor deposition layer having a thickness of 1.5 times or more of the incident wavelength formed on a region other than the effective diameter of the transmission surface of the optical element or on the total reflection surface, and a vapor deposition layer formed on the entire transmission surface or total reflection surface and deposited on the surface and the total reflection surface. A bonding layer of an optical element, consisting of an adhesive layer that bonds the layer to another member.