JPH08122505A - Optical member - Google Patents

Abstract

PURPOSE: To decrease the residual stresses of an optical member at the time of molding and to lessen the generation of manufacturing errors by forming the joint surfaces of joint parts for joining plural optical parts into a specific shape and smoothly connecting the two surfaces. CONSTITUTION: The reflection parts A having reflection surfaces 1a of a prescibed curvature and the optical parts B having reflection surfaces 2a different from the extension surfaces of the reflection surfaces 1a are integrally joined via the joint parts T. The boundaries of the joint parts T of the surfaces 1a and the surface 2a are smoothly connected and are integrally molded while satisfying the conditions F1a (xt1 )=fta (xt1 ), f2a (xt2 )=f2a (xt2 ), f1a '(xt1 )=fta '(xt1 ), f2a '(xt2 )=fta '(xt2 ), where f1a (x) is a function x>xt1 stating the surfaces 1a, f2a (x) is a function x<xt2 stating the surfaces 2a, fta (x) is the function xt2 <x<xt1 stating the joint surfaces ta, f1a '(x), f2a '(x), fta '(x) are the functions indicating the inclination of the surfaces, xt1 , xt2 are the position vector of the joint parts T.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical member, and more particularly to a first optical component having a first surface having a predetermined curvature and a second optical component having a surface different from an extension surface of the first surface. The present invention relates to an integrated optical member.

[0002]

2. Description of the Related Art In recent years, with the progress of optical design technology, optical devices composed of optical systems including complicated curved surfaces have been widely used. One of them uses an optical system that includes multiple optical axes, where some optical components are not arranged on a common optical axis. In the case of these optical systems, it is difficult to secure sufficient accuracy during assembly, as compared with the coaxial optical system having a common optical axis. Further, in the case of an optical system using a reflecting mirror, one optical component may be disposed near another optical component in the direction perpendicular to the optical axis. Here, as a method of ensuring accuracy, it is conceivable to integrally manufacture a plurality of parts located in the vicinity to maintain accuracy. This reduces the number of parts and facilitates assembly. For example, USP 5,253116 discloses a display device for a flight simulator in which two reflecting mirrors (optical parts) are configured by one mirror.

As a technique for such integral molding, for example, compression molding using a synthetic resin or the like as a molding material and injection molding are frequently used as a technique advantageous for weight reduction.

Injection molding is the most productive processing method, and molding using a synthetic resin has the advantage that molding is relatively easy. Further, even if an optical member such as an aspherical lens which is extremely difficult to machine as a curved surface is formed into a single mold, a large number of optical members can be easily molded and manufactured.

[0005]

However, in the processing using a synthetic resin, it is necessary to consider shrinkage at the time of molding and dimensional change in the use environment because its coefficient of thermal expansion is an order of magnitude higher than that of an inorganic material. In terms of optical characteristics, it is important to consider mold shrinkage and molecular orientation in addition to mold precision. Needless to say, the molding shrinkage affects the dimensional accuracy of the entire molded product, but the local shrinkage during cooling appears as residual strain and deformation.

Further, when the molding material is solidified in the mold, it cannot generally shrink freely, so that the stress for shrinking remains. For soft materials, when the molded product is taken out of the mold, such stress is released and appears as warps, but for hard materials such as polystyrene, polymethylmethacrylate, and polycarbonate, the stress is not released and leaves stress. It retains its original shape. The stress in this case is called internal stress, and cracks are likely to occur when exposed to a solvent, for example, and even spontaneously break during use.

By the way, when a plurality of optical components are to be integrally molded into one optical member, if the surfaces of the optical components to be joined are part of one surface or have a surface shape close to that, they are directly joined. But it doesn't really matter. However, when two optical surfaces that are not on one smooth surface are to be joined together, various surface shapes of the surfaces (joint surfaces) between the optical surfaces must be properly designed. Problems occur.

That is, in injection molding or the like, if there is a step at the surface-to-surface joint or if the surface shape is discontinuous, a force is applied to this portion when it is solidified and removed from the mold, and is deformed. There is. In addition, the possibility that it will remain as an internal stress also increases. It is not just a matter of connecting cross sections.

The technique disclosed in US Pat. No. 5,253,116 does not show a means for determining the surface shape of the joint portion, and the surface shape of the joint portion cannot be determined in actual manufacturing. That is, USP 5,253,116 does not disclose a specific method for forming a joint surface, and it is practically very difficult to carry out the method.

An object of the present invention is to appropriately form a joint surface shape of a joint portion for joining a plurality of optical components when integrally molding a plurality of optical components having curved surfaces having different curvatures as one optical member, An object of the present invention is to provide an optical member in which two surfaces are smoothly connected at a boundary between an optical component and a joint portion, thereby reducing residual stress on the optical member at the time of molding and reducing manufacturing errors. In addition, the number of parts is reduced, the number of assembling steps is reduced, and a highly accurate optical member that realizes cost reduction is provided.

[0011]

The structure of the optical member of the present invention comprises (1-1) a first optical component having a surface 1a having a predetermined curvature, and a surface 2a different from the extension surface of the surface 1a. The second optical component is connected via a joint portion, and further, the surface 1a and the boundary between the surface 2a and the joint portion are smoothly connected, and the condition f _1a (x _t1 ) = f _ta ( x _t1 ), f _2a (x _t2 ) = f _ta (x _t2 ) f _1a '(x _t1 ) = f _ta ' (x _t1 ), f _2a '(x _t2 ) = f _ta ' (x _t2 ), where f _1a (x): Function x> x describing the surface 1a of the first optical member
_t1 f _2a (x): Function describing surface 2a of the second optical member x <x _t2 f _ta (x): Function describing surface ta of the joint part x _t2 <x <x _t1 f _1a '(x ), F _2a '(x), f _ta ' (x): Functions representing the inclination of the surface x _t1 , x _t2 : characterized by being manufactured by integral molding that satisfies the position vector of the joint There is.

In particular, (1-1-1) the first optical component has a surface 1b having a predetermined curvature, and the second optical component has a surface 2b different from an extension surface of the surface 1b, The surface 1b and the surface 2b are connected to each other via the joint portion, and further, the boundary between the surface 1b and the surface 2b and the joint portion is smoothly connected, and the condition f _1b (x _t3 ) = f _tb (x _t3 ), f _2b (x _t4 ) = f _tb (x _t4 ) f _1b '(x _t3 ) = f _tb ' (x _t3 ), f _2b '(x _t4 ) = f _tb ' (x _t4 ) Where f _1b (x): Function x> x that describes the surface 1b of the first optical member
_t3 f _2b (x): Function describing the surface 2b of the second optical member x <x _t4 f _tb (x): Function describing the surface tb of the junction x _t4 <x <x _t3 f _1b '(x ), F _2b '(x), f _tb ' (x): Functions representing the inclination of the surface x _t3 , x _t4 : The position vector of the joint is satisfied.

Further, the structure of the optical member of the present invention includes (1-2) a first optical component having a surface 1a having a predetermined curvature and a second optical member having a surface 2a different from an extension surface of the surface 1a. The parts are connected to each other at a joint part having a smooth joint surface using a Bezier curve, and are manufactured by integral molding.

In particular, (1-2-1) the first optical component has a surface 1b having a predetermined curvature, and the second optical component has a surface 2b different from an extension surface of the surface 1b, The surface 1b and the surface 2b are connected by a smooth joint surface using a Bezier curve.

[0015]

EXAMPLE 1 FIG. 1 is a perspective view of Example 1 of the present invention. In this embodiment, a reflective component (first optical component) A having a reflective surface 1a (first surface) having a predetermined curvature, and a reflective component having a reflective surface 2a (second surface) different from the extended surface of the reflective surface 1a. An optical member having a shape in which (second optical component) B and a second portion are integrally joined via a joint portion T is shown. The optical member of this embodiment constitutes, for example, a part of the reflective optical system of the image display device.

In this embodiment, the first surface 1a and the second surface 2a
The structure of the joint surface ta for smoothly joining and will be described. The coordinate system is set as shown in Fig. 2, and the shape of the first surface 1a is f
_1a (x, y), the shape of the second surface 2a is f _2a (x, y), and the shape of the joint surface ta is f _ta (x, y). Examples of these functions include a spherical surface, an aspherical surface to be rotated, and a rotationally asymmetrical aspherical surface. The effective area (used area) of f _1a (x, y) is x> x1 The effective area (used area) of f _2a (x, y) is x <x2.

In FIG. 3A, y = 1 on the first surface 1a and the second surface 2a.
It is an enlarged view near the boundary of 0 cross section. Even in this xz cross-sectional view, not only the height (z value) of the function f _1a (x, 0) and the function f _2a (x, 0) are different, but also the inclination of the surface is greatly different. When the surface 1a is extended in the direction of the surface 2a, the surface 2a is not on the extension line of the surface 1a, and the surface 2a is clearly different from the extension line of the surface 1a. If the function f _1a (x, y), f
_{Even if 2a} (x, y) is extended and intersects at the junction area, it becomes discontinuous at the intersection. Furthermore, in FIG. 3B, x = x
It shows the yz cross section at 1, x2. Also in this cross-sectional view, the two curves have different position shapes.

Therefore, at x = x1, the first surface 1a and the joint surface t
a, and the joint surface ta and the second surface 2a at x = x2, xz
, Yz Function f of joint surface ta that smoothly connects both cross sections
Determine _ta (x, y). The function f _ta (x, y) of the joint surface ta is the first
This joint surface ta is f _1a (x1, y) = f _ta (x1, y) f _2a (x2, y) = f _ta (x2, y) in order to smoothly connect the surface 1a and the second surface 2a.

[0019]

[Equation 1] I am trying to meet the condition of.

FIG. 4 shows y = 2 of two reflecting surfaces connected by the function f _ta (x, y) of the joint surface ta determined by satisfying the above conditions.
It is a xz sectional view in 0. FIG. 5 is an enlarged view of the vicinity of the joint surface ta. As can be seen from both figures, the first surface 1a and the second surface 2a are smoothly connected to the joint surface ta at x = x1, x2.

Next, the back sides of the two reflecting surfaces, that is, the surface 1b of the first optical component A and the surface 2b of the second optical component B are connected. If the functions representing the respective surfaces are f _1b (x, y) and f _2b (x, y), the function f _tb (x, y) of the joint surface tb of the joint portion T is determined by the same method as that determined on the reflecting surface side. ) Is obtained, and the surface 1b, the surface tb, and the surface 2b are smoothly connected to determine both surfaces of the optical member.

Since the entire surface of the optical component determined in this way is composed of smooth curves on both sides, no stress remains at the joint portion of the component even when it is manufactured by molding, and deformation after processing occurs. Thus, it is possible to obtain an optical member with high accuracy that does not cause damage or the like.

Further, in the present invention, the joining surface of the first surface and the second surface may be joined by a smooth curve using a Bezier curve. For example, as shown in Fig. 6, the function is in the range of x <x1.
When describing a range of x1 <x <x2 as a cemented surface in an optical member that has two surfaces defined by f _1a (x) and a function f _2a (x) in the range of x> x2 , The function w shown in FIG.
₁ (x), w ₂ (x), eg cosine function w ₁ = [1 + cos {(x-x1)
Considering / (x2-x1) * π}] / 2 w ₂ = [1 + cos {(x-x2) / (x2-x1) * π}] / 2, the function of the interface is f _ta (x) = f _1a (x) * w ₁ (x) + f _2a (x) *
If w ₂ (x), the function f _1a (x) and the function f _2a (x) can be smoothly connected. Connecting the joining surfaces with a Bezier curve has the advantage of facilitating the design of the joining surfaces.

[0024]

According to the present invention, with the above configuration, when integrally molding a plurality of optical components as one optical member,
Appropriately configure the joint surface shape of the joint part that joins multiple optical parts, and smoothly connect the two surfaces at the boundary between the optical part and the joint part, which reduces residual stress on the optical member during molding. This reduces the number of manufacturing errors. As a result, it is possible to reduce the number of parts, reduce the number of assembling steps, and achieve a highly accurate optical member that realizes cost reduction.

[Brief description of drawings]

FIG. 1 is a perspective view of a first embodiment of the present invention.

FIG. 2 is a diagram showing a first surface, a second surface, and a coordinate system of the embodiment of FIG.

FIG. 3 is an enlarged cross-sectional view in the vicinity of a joint between the first surface and the second surface of the embodiment shown in FIG.

FIG. 4 is a cross-sectional view of the first surface, the second surface, and the bonding surface of the embodiment of FIG.

5 is a cross-sectional view of the vicinity of the joint surface of the embodiment of FIG.

FIG. 6 is a conceptual diagram in which the first surface and the second surface of the optical member of the present invention are connected by a Bezier curve.

[Explanation of symbols]

A reflective component (optical component) B reflective component (optical component) T joint part 1a reflective surface (first surface), surface shape function f _1a (x, y) 2a reflective surface (second surface), surface shape function f _2a (x, y) 1b Backside of surface 1a, surface shape function f _1b (x, y) 2b Backside of surface 2a, surface shape function f _2b (x, y) ta Join surface, surface shape function f _ta (x, y) tb Joint surface, surface shape function f _tb (x, y)

Claims (4)

[Claims] 1. A first optical component having a surface 1a having a predetermined curvature, and a second optical component having a surface 2a different from an extension surface of the surface 1a.
Of the optical components are connected via a joint portion, and the surfaces 1a and 2a and the boundary between the joint portion are smoothly connected, and the condition f _1a (x _t1 ) = f _ta (x _t1 ), F _2a (x _t2 ) = f _ta (x _t2 ) f _1a '(x _t1 ) = f _ta ' (x _t1 ), f _2a '(x _t2 ) = f _ta ' (x _t2 ), where f _1a (x): Function x> x describing the surface 1a of the first optical member
_t1 f _2a (x): Function describing surface 2a of the second optical member x <x _t2 f _ta (x): Function describing surface ta of the joint part x _t2 <x <x _t1 f _1a '(x ), F _2a '(x), f _ta ' (x): Functions representing the inclination of the surface x _t1 , x _t2 : It is characterized by being manufactured by integral molding that satisfies the position vector of the joint. Optical member to do. 2. The first optical component is a surface 1 having a predetermined curvature.
b, the second optical component has a surface 2b different from the extension surface of the surface 1b, the surface 1b and the surface 2b are connected to each other through the joint portion, and the surface 1b is further provided. And the surface 2b
And the boundary of the joint are smoothly connected, and the conditions f _1b (x _t3 ) = f _tb (x _t3 ), f _2b (x _t4 ) = f _tb (x _t4 ) f _1b '(x _t3 ) = f _tb '(x _t3 ), f _2b ' (x _t4 ) = f _tb '(x _t4 ), where f _1b (x): Function x> x describing the surface 1b of the first optical member.
_t3 f _2b (x): Function describing the surface 2b of the second optical member x <x _t4 f _tb (x): Function describing the surface tb of the junction x _t4 <x <x _t3 f _1b '(x ), F _2b '(x), f _tb ' (x): a function x _t3 , x _t4 representing the inclination of the surface: x _t4 : a position vector of the joint, The optical member according to claim 1. 3. A first optical component having a surface 1a having a predetermined curvature, and a second optical component having a surface 2a different from an extension surface of the surface 1a.
The optical member is connected with a joint portion having a smooth joint surface using a Bezier curve, and is manufactured by integral molding. 4. The first optical component is a surface 1 having a predetermined curvature.
b, the second optical component has a surface 2b different from the extension surface of the surface 1b, and the surface 1b and the surface 2b are connected by a smooth joint surface using a Bezier curve. The optical member according to claim 3, wherein