JPH01287601A - Cemented lens - Google Patents

Abstract

PURPOSE:To improve the productivity of a cemented lens by cementing a 1st lens which is made of glass and has a rough cementing surface to a 2nd lens which is made of glass having a refractive index different from that of the glass of the 1st lens and has a ground cementing surface at the cementing surfaces with a cementing agent having a refractive index which is nearly equal to that of the 1st lens. CONSTITUTION:One of the lenses used in this cemented lens is a lens A1 having a ground surface (rough surface) 1a on the cementing side and the other is a glass lens or molded plastic lens B2 having a refractive index which is different from that of the lens A1 and ground surfaces including a cementing surface 2a. Therefore, high spherical accuracy can be obtained on the cementing surface 2a of the lens B2 and, accordingly, the lenses A1 and B2 are cemented to each other equivalent to a cemented lens constituted of lenses having ground cementing surfaces even when the cementing surface 1a of the lens A1 is ground surface (rough surface) when the lenses A1 and B2 are cemented to each other with a cementing agent 3 having a refractive index which is almost equal to that of the lens A1. In other words, the cementing surface 1a of the lens A1 coated with the cementing agent 3 can be regarded as a ground surface. Therefore, the process required for grinding the cementing surface 1a of the lens A1 can be omitted and the cost of this cemented lens can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a cemented lens in which lenses are bonded together using a bonding agent.

BACKGROUND ART A desired spherical precision and appearance can be obtained by grinding and then polishing a glass lens. However, it is difficult to simultaneously satisfy spherical precision and appearance and to produce it at a low cost, and it is generally expensive.

On the other hand, when glass lenses are made by molding, the grinding process can be omitted and the desired lens can be obtained with only a polishing finish, but the polishing process takes a long time, making it difficult to produce lenses at a low cost. .

Furthermore, in the case of a cemented lens, the lenses to be cemented together are polished, and the production of the cemented lens is also costly due to the polishing work. As yet, the refractive index of the cementing agent used to bond lenses together has not been set in a specific relationship with the refractive index of the lenses to be bonded.

Problems to be Solved by the Invention Accordingly, an object of the present invention is to eliminate the need for a long time in the processing process,
The object of the present invention is to provide a cemented lens that can be produced at low cost.

Means for Solving the Problems In order to achieve the above object, the present invention utilizes the fact that when a glass surface is treated with a substance having a refractive index similar to that of glass, transmitted light is no longer scattered. That is, the cemented lens of the present invention includes a first lens made of glass whose cemented surface is a rough surface, and a second lens whose cemented surface is a polished surface and has a refractive index different from that of the first lens. lens and
and a cementing agent having a refractive index substantially equal to the refractive index of the first lens, and the bonding surfaces of the first lens and the second lens are bonded together with the cementing agent. The joint surface of the first lens is a square-ground surface, or if the first lens is made by molding, the joint surface is a non-polished surface. .

Effect With the above configuration, the cemented lens of the present invention uses an inexpensive lens that does not require a polishing process for one of the cemented surfaces. In addition, the cemented surface of the first lens made of glass, which is not a polished surface, can be regarded as a polished surface due to the cementing agent and the polished surface of the second lens. Has equivalent performance.

Example Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a completed state of the cemented lens according to the present invention, which is a lens B having a refractive index. (3) is a bonding agent, and in this embodiment, the refractive index of the bonding agent (3) and the refractive index of the lens A (1) are approximately equal. Generally, it is known that if the glass surface is treated with a substance having a refractive index similar to that of glass, scattering will no longer occur on the glass surface.

In this embodiment, this property is utilized to make the bonding side surface (1a) of the lens A(1) a ground surface (rough surface). The surface of the lens A(1) opposite to the cemented surface is polished in the conventional manner. Further, the lens B (2) is a glass lens whose cemented surface (2a) and the opposite surface are both polished, or a plastic lens made by molding. Note that a plastic lens made by molding has a higher surface area than a glass molded lens, and can be used as an optical lens as is.

Therefore, since the cemented surface (2ag) of lens B (2) has a high spherical precision, the cemented surface (1,a) of lens A (1)
) is a ground surface (rough surface), both lens A (1) and lens B (2) can be polished by bonding agent (3) having a refractive index almost equal to that of lens A (1). It has the same performance as a cemented lens made of lenses that have been treated with In other words, lens A (1) and bonding agent (3) are
It can be seen as a surface with a polished finish.

Furthermore, as another embodiment of the present invention, the lens A(1) may be a glass molded lens.

In this case, the surface of the glass molded lens has the same precision as the ground surface (rough surface), so the bonding surface (1
a) may be left as is or rough polished to form a joint surface (1a
) by polishing the surface opposite to lens A.
It can be used as (1).

In general, the roughness of the machined surface of a polished lens is such that the radius of curvature of the concave and convex portions is at most 0.01 to 0.03 μm. On the other hand, the surface roughness of the cemented surface of the lens A(1) of the present invention is sufficient if the maximum radius of curvature is 02 μm.

As a specific configuration of the present invention, the refractive index of lens A (1) is Nd=1.5168, and the refractive index of lens B (2) is Nd=1.5168.
When d=1.80741, N d as bonding agent (3)
By using an ultraviolet curing adhesive (trade name: PH0TOBOND 3010) having a refractive index of = 1.51400, a cemented lens having the same function as a conventional cemented lens can be obtained. Incidentally, since the refractive index of the cementing agent is generally low, among the lenses whose cemented surfaces are cemented together, the cemented surface of the lens with a low refractive index may be a ground surface or an unpolished surface of a molded glass lens.

Effects of the Invention As has been explained in detail above, the cemented lens of the present invention has performance equivalent to that of a conventional cemented lens formed by bonding two polished surfaces, and one of the bonded surfaces is a ground surface, Alternatively, since a molded glass lens can be used without polishing, a part of the process required for polishing can be omitted, and costs can be reduced.

Similarly, since there is no need to polish one of the cemented surfaces, the accuracy of the core thickness of the lens is improved compared to conventional cemented lenses.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing a completed state of an embodiment of a cemented lens according to the present invention, and FIG. 2 is a sectional view showing the lens before bonding. 1...Glass lens, 2...Lens, 1a, 2a・
... Bonding surface, 3... Bonding agent. Applicant: Minolta Camera Co., Ltd.

Claims (1)

[Claims] 1. A first lens made of glass whose cemented surface is a rough surface, and a second lens whose cemented surface is a polished surface and has a refractive index different from the refractive index of the glass lens; a cementing agent having a refractive index substantially equal to the refractive index of the first lens, and the bonding surfaces of the first lens and the second lens are bonded together with the cementing agent. cemented lens. 2. The cemented lens according to claim 1, wherein the cemented surface of the first lens is a ground surface. 3. The cemented lens according to claim 1, wherein the first lens is a molded glass lens, and the cemented surface of the first lens is a non-polished surface. 4. The cemented lens according to claim 1, wherein the first lens has a lower refractive index than the second lens. 5. The refractive index of the first lens is 1.5168, the refractive index of the second lens is 1.80741, and the refractive index of the bonding agent is 1.514. cemented lens. 6. The cemented lens according to claim 1, wherein the first lens is a positive lens and the second lens is a negative lens.