JPH06313846A - Optical equipment - Google Patents

Abstract

PURPOSE:To provide optical equipment further reducing light intercepting quantity while holding the rigidity of a supporting member intercepting an optical path so as to impede the lowering of transmitted wave face aberration, thereby improving reflecting efficiency. CONSTITUTION:Optical equipment is provided with a main reflecting mirror 4 formed of a large diameter concave mirror provided with a light transmitting part 6 along an optical axis K, and an auxiliary reflecting mirror 10 formed of a small diameter convex mirror disposed on the optical axis, opposedly to the main reflecting mirror 4. Incoming light to the main reflecting mirror 4 from the periphery of the auxiliary reflecting mirror 10, and incoming light to the auxiliary reflecting mirror 10 from the light transmitting part 6 of the main reflecting mirror 4 are mutually in the reflected relation by the main reflecting mirror 4 and the auxiliary reflecting mirror 10 so as to enlarge or reduce the flux of light. The main reflecting mirror 4 and the auxiliary reflecting mirror 10 are accommodated inside a lens-barrel 1, and a supporting member 2 is provided to support the main reflecting mirror 4 and auxiliary reflecting mirror 10 in the specified positions in relation to the lens-barrel 1. The light irradiation face F of a support 7 positioned in the optical path of the supporting member 2 is formed to be narrow in width dimension (a) in opposition to the light proceeding direction.

Description

Detailed Description of the Invention

[0001]

INDUSTRIAL APPLICABILITY The present invention can be used not only as an image forming function of light having a small output as in an astronomical telescope, but also as a light collecting function of light having a large output such as CO2 laser light. Regarding optical equipment.

[0002]

2. Description of the Related Art A main reflecting mirror consisting of a large-diameter concave mirror provided with a light-transmitting portion along an optical axis, and a sub-reflecting surface consisting of a convex mirror facing the main reflecting mirror and having a small diameter on the optical axis. There is an optical device with a mirror.

When this kind of optical equipment is used, for example, as an astronomical telescope, the back surface of the sub-reflecting mirror faces the celestial body, and weak light scattered from space enters the main reflecting mirror from around the sub-reflecting mirror. Light up.

The main reflecting mirror is a parabolic mirror whose reflecting surface is a concave surface, and reflects the incident light toward the sub reflecting mirror. The sub-reflecting mirror is a hyperboloidal mirror whose reflecting surface is a convex surface, and reflects toward the translucent portion of the main reflecting mirrors facing each other, particularly the optical axis. Then, the light transmitted through this light transmitting portion is focused and imaged at a position outside the main reflecting mirror.

It is used as a so-called reflection telescope, and an image of an object is formed by utilizing the reflection action of a reflection mirror (objective mirror) instead of the objective lens in the refraction telescope. For example, it is known as a Cassegrain type optical system or a Rich Clean type optical system.

This kind of optical equipment is used not only as an astronomical telescope, but also as an optical communication means for catching a weak laser beam emitted from a very distant place by positioning it in outer space with some improvement. Or number
It can also be used as a condensing function for high-power light such as CO 2 laser light of kW unit.

[0007]

By the way, not only the main reflecting mirror but also the sub-reflecting mirror must be arranged at a predetermined position so as to face each other on the optical axis. Specifically, both the main reflecting mirror and the sub-reflecting mirror are supported by a supporting member housed in the lens barrel, and this supporting member is attached and fixed to a predetermined portion of the lens barrel.

The main reflecting mirror has a large diameter and almost coincides with the inner diameter of the lens barrel. However, the sub-reflecting mirror must have a smaller diameter than the main reflecting mirror and must be positioned on the optical axis.

The support member is required to support the sub-reflecting mirror in a hollow state, and due to its structure, extends from the lens barrel to the sub-reflecting mirror across the optical path. In other words, the support member that supports the sub-reflector blocks the optical path.

Usually, this portion is a support of a plurality of round rods or square rods made of glass material or carbon material, one end of which supports the sub-reflecting mirror and the other end of which is connected to the lens barrel. . If the diameter is made small in order to reduce the amount of blocking the optical path, there is a possibility that the required rigidity cannot be ensured, which makes the optical system unstable and adversely affects the light collecting and imaging performance. Further, if the diameter is increased to secure the rigidity, the amount of blocking the optical path becomes large this time, and the amount of light becomes insufficient, resulting in deterioration of characteristics such as reflection efficiency.

Therefore, it is necessary to prevent the reduction of the transmitted wavefront aberration by reducing the amount of blocking the optical path as much as possible while ensuring the required rigidity. On the other hand, as described above, there are two types of light using this type of optical device: one is to obtain an image forming function for light with a small output, and the other is to obtain a light condensing function for light with a large output. is there.

That is, light having contradictory characteristics is guided along the optical path, and this light is blocked by the support member that supports the sub-reflecting mirror. Therefore, it is necessary to take effective measures according to each application, especially on the surface of the support member that receives the light irradiation.

Further, unless the relative positions of the main reflecting mirror and the sub-reflecting mirror are set accurately, the light reflection accuracy cannot be kept high. As a unit of adjustment, a sub synchrometer on the order of μm or less is required.

For that purpose, it is convenient if the supporting member for supporting the sub-reflecting mirror has a structure capable of adjusting the optical axis even partially, but in reality, it is a mere rigid body, and adjustment is not possible. It is impossible.

The optical axis can be adjusted by interposing an optical axis adjusting mechanism separately between the supporting member and the sub-reflecting mirror. However, this kind of mechanism is large and heavy, and the optical device is large. Is not suitable for the purpose of use. In addition, it is impossible to maintain a highly accurate and highly versatile support, and it is impossible to maintain the adjusted state for a long time.

The present invention has been made under such circumstances, and a first object of the present invention is to reduce the amount of light interception while reducing the amount of light interception while maintaining the rigidity of the support member that intercepts the optical path. It is to provide an optical device with improved efficiency.

The second object is to perform a surface treatment on the light irradiation surface of the support member in the optical path, which is optimum for the characteristics of the reflected light.
An object is to provide an optical device that adapts to the characteristics of each light.

A third object is to provide an optical device of high precision and high resolution, which is capable of adjusting the optical axis even in the assembled state and is provided with a supporting member for holding the position. .

[0019]

In order to achieve the above first object, an optical apparatus according to the present invention comprises a main reflecting mirror comprising a large-diameter concave mirror having a light transmitting portion along the optical axis, and an optical axis. A sub-reflecting mirror consisting of a small-diameter convex mirror arranged opposite to the main reflecting mirror is provided, and light enters the main reflecting mirror from the periphery of the sub-reflecting mirror or from the light transmitting portion of the main reflecting mirror. In the optical device for reducing or enlarging the light flux, the main reflecting mirror and the sub-reflecting mirror have a reflection relationship with each other for light entering the sub-reflecting mirror, and the main reflecting mirror and the sub-reflecting mirror are housed therein. A rectangular shape of the supporting member, which includes a lens barrel and a supporting member that supports the main reflecting mirror and the sub-reflecting mirror at predetermined positions with respect to the lens barrel and has a rectangular cross section in the traveling direction of light. The cross section has a width that is opposite to the light traveling direction than a width that is parallel to the light traveling direction. An optical device, characterized in that the Ku formed.

In order to achieve the second object, an optical apparatus according to the present invention comprises a main reflecting mirror and a sub-reflecting mirror for expanding or contracting a light beam, and the main reflecting mirror and the sub-reflecting mirror are
A supporting member for supporting the main reflecting mirror and the sub-reflecting mirror at a predetermined position is provided with respect to the lens barrel housed therein, and is located in the optical path of the supporting member, and has a width facing the traveling direction of light. When the narrowly formed part is used as a light-collecting function for high-power light, it should be a reflecting surface having high reflection characteristics.
Alternatively, when it is used as an image forming function of light with a small output, it is characterized by having a reflecting surface having a non-reflection characteristic.

In order to achieve the third object, an optical apparatus according to the present invention comprises a main reflecting mirror and a sub-reflecting mirror for expanding or contracting a light flux, and the main reflecting mirror and the sub-reflecting mirror are
A supporting member for supporting the main reflecting mirror and the sub-reflecting mirror at predetermined positions is provided for the lens barrel housed therein, and the supporting member is a light for at least one of the main reflecting mirror and the sub-reflecting mirror. It is characterized in that it is provided with a minute displacement element for adjusting the axis.

[0022]

In the first aspect of the invention, since the portion of the support member located in the optical path has a narrow width facing at least the traveling direction of the light, the amount of blocking the light becomes small and the transmitted wavefront aberration is reduced. Can be prevented. The required rigidity can be ensured by providing a width along the light traveling direction.

In the second aspect of the invention, when it is used as a light-collecting function for high-power light, since the surface of the supporting member facing the light traveling direction is an optical reflecting surface having high reflection characteristics, the supporting member is large. It is not damaged by the irradiation of output light.

When used as an image forming function of light with a small output,
Since the surface of the supporting member facing the traveling direction of the light is an optical reflection surface having a non-reflection characteristic, the light irradiating the supporting member is not scattered or becomes stray light, and higher imaging performance is obtained. . In the third aspect of the invention, the supporting member itself has the optical axis adjusting function, so that another adjusting component is not necessary and the four positions are held.

[0025]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. 1 and 2 show a schematic configuration of an optical device. In the figure, reference numeral 1 denotes a lens barrel having, for example, a cylindrical barrel having openings at both ends, and it does not matter whether it is a transparent body or an opaque body, but it is necessary to maintain the minimum necessary rigidity.

An opening at one end of the lens barrel 1 is closed by a closing plate 3 which constitutes a supporting member 2, and a main reflecting mirror 4 whose optical axis K is aligned is attached and supported along the central axis. The main reflecting mirror 4 has a diameter slightly smaller than the diameter of the closing plate 3,
It is formed to have a diameter larger than that of the sub-reflecting mirror 10 described later. To be more specific, the light transmitting portion 5 is formed along the central axis of the closing plate 3.
And a light transmitting portion 6 having the same diameter is provided along the optical axis K of the main reflecting mirror 4. Therefore, the translucent parts 5 and 6 communicate with each other.

A support member 3 is provided at the opening of the other end of the lens barrel 1.
The outer ends of the columns 7 are connected to each other, and the annular body 8 is connected to the inner ends thereof. The structure of the columns 7 and the annular body 8 is detailed in FIG.

That is, the support columns 7 are three strip plate members in this case, and are provided so as to project at an equal angle to the central axis of the annular member 8 (which coincides with the optical axis K). Become. Each prop 7
Is set so that the width dimension a of the surface orthogonal to the optical axis K is made as thin as possible within the range where the rigidity allows. The width b of the surface along the optical axis K is set in consideration of the safety factor, on the condition that sufficient rigidity is ensured.

For this reason, the pillar 7 has a rectangular cross section F with respect to the light traveling direction, and the rectangular cross section F is formed to be narrower than the plane G parallel to the light traveling direction. . The pillar 7 is made of a material having a large Young's modulus, which is suitable as a spring material. It is desirable to select a coefficient of thermal expansion that matches that of the annular body 8 and the lens barrel 1.

The surface F of the pillar 7 which is orthogonal to the optical axis K direction is surface-treated according to the application as an optical device. For example, when it is used as a function of condensing light with a large output, it is necessary to perform a treatment having a high reflection characteristic.

When used as an image-forming function for light with a small output, the surface F of the column 7 which is orthogonal to the direction of the optical axis K must be treated so as to have a non-reflective property with excellent light absorption efficiency. I won't.

The annular body 8 is set such that its axial length matches the width dimension of the surface G of the column 7 along the optical axis K direction. As shown in FIGS. 1 and 2 again, a sub-reflecting mirror support plate 11 for mounting and supporting the sub-reflecting mirror 10 is fitted and fixed to the inner diameter portion of the annular body 8.

That is, the central axis of the sub-reflecting mirror support plate 11 coincides with the optical axis K of the sub-reflecting mirror 10 attached thereto. Thus, light having a relatively large luminous flux diameter is guided into the lens barrel 1 via the support member 2 that is provided between the periphery of the sub-reflecting mirror 10 and the lens barrel 1.

This light enters the main reflecting mirror 4 and is reflected. Since the main reflecting mirror 4 is a concave mirror, it reflects a light beam in a narrowed state. The sub-reflecting mirror is located so as to face this reflection direction, and the sub-reflecting mirror 10 that receives the light reflects again toward the main reflecting mirror 4.

Here, the light flux is further narrowed down, passes through the respective light transmitting portions 5 and 6, and is focused outside the closing plate 3. Conversely, light with a small luminous flux can be expanded.

That is, light with a small light beam diameter entering the lens barrel 1 from the outside of the blocking plate 3 through the light transmitting portions 5 and 6 is guided along the optical axis K. This light is reflected by the sub-reflecting mirror 10 and further reflected by the main reflecting mirror 4. Eventually, the light flux is guided to the outside of the lens barrel 1 from around the sub-reflecting mirror 10 in the expanded state.

In any case, light is transmitted between the sub-reflecting mirror 10 and the lens barrel 1. At this position, in particular, the columns 7 of the support member 2 are provided so as to partially block light. However, the column 7 has a width dimension a of a light irradiation surface F which is a surface (a surface orthogonal to the optical axis K) facing the traveling direction of light.
Since it was set to be narrower, less light is blocked,
It suppresses the reduction of transmitted wavefront aberration.

Further, the column 7 is a light traveling direction (optical axis K).
Since the width dimension b of the column 7 is increased along with, and a material having a high Young's modulus is selected, high rigidity is maintained, tension is easily applied, and the support for the sub-reflecting mirror 10 is stabilized. can get.

In addition, the light irradiation surface F of the column 7 is subjected to different surface treatments depending on the use as an optical device, that is, the characteristics of light. When used as an astronomical telescope or as an optical communication means for catching a weak laser beam located in outer space, the support 7
The light-irradiated surface F is subjected to a surface treatment having non-reflection characteristics.

This prevents light from striking the corners of the column 7 and scattering, or being reflected as stray light. Therefore, noise is suppressed and the imaging performance is improved. Eggplant

Further, for example, when the CO 2 laser light of several kW unit is used as a condensing function of high output light such as cutting, the light irradiation surface F of the column 7 has a high reflection characteristic. Surface treatment.

As a result, the high-power light striking the light irradiation surface F of the column 7 is highly reflected here, has no adverse effect on the column 7, and can prevent problems such as damage. Figure 4
An example in which the minute displacement element S is integrally provided on the column 7a is shown.

That is, a piezoelectric element 20, which is a minute displacement element, is interposed between the outer end of each of the columns 7a and the connecting portion of a lens barrel (not shown). The piezoelectric element 20 has vertical and horizontal directions (XY directions).
And a material that can be slightly expanded and contracted in the optical axis direction (Z direction) is used.

A strain gauge 21, which is a displacement amount detecting means, is provided between the inner end of the column 7a and the annular body 8. The strain gauge 21 records an output in a state where the piezoelectric element 20 is expanded and contracted in a necessary direction to adjust the optical axis of the sub-reflecting mirror 10, and the gauge output at the time of best adjustment is stored.

Therefore, under some circumstances, the sub-reflecting mirror 10
Even if the position of the optical axis is shifted, the return adjustment can be performed in the optimum state. Although the minute displacement element S is described as the piezoelectric element 20 in the above embodiment, the present invention is not limited to this, and may be replaced by, for example, a photostrictive element or a magnetostrictive element.

A minute displacement element Sa as shown in FIG. 5 may be used. In this case, the sub-reflecting mirror support plate 11a is made of a shape memory alloy, and a high temperature heater 22 and a thermometer 23 made of an electric resistor or the like are provided on the back surface side of the supporting surface of the sub-reflecting mirror 10 here.

Then, the sub-reflecting mirror support plate 11a made of a shape memory alloy is displaced to adjust the optical axis, and the position can be memorized by the heating action of the high temperature heater 22 during the best position adjustment.

In the above embodiment, the minute displacement elements S and Sa are provided for adjusting the optical axis of the sub-reflecting mirror 10, but the present invention is not limited to this, and the light of the main reflecting mirror 4 is not limited thereto. It may be provided for adjusting the axis, or may be provided so as to adjust the optical axes of both the main and sub-reflecting mirrors 4 and 10 at the same time.

The lens barrel 1 does not necessarily have to be a cylindrical body. That is, one end may be directly connected to the main reflecting mirror 4, and the other end may be directly connected to the ends of the columns 7 ... In this case, both the main reflecting mirror 4 and the sub-reflecting mirror 10 are exposed, but depending on the application, they are sufficiently durable.

[0050]

As described above, according to the first aspect of the present invention, the portion of the supporting member located in the optical path has a rectangular cross section whose width with respect to the light traveling direction is smaller than the width parallel to the light traveling direction. Since the support member that blocks the optical path is kept rigid, the amount of light that is blocked is further reduced, the reduction of the transmitted wavefront aberration is suppressed, and the reflection efficiency is improved.

According to the second aspect of the present invention, the portion of the support member located in the optical path is narrowed at least so as to face the light traveling direction, and the surface facing the light traveling direction is
When used as a light condensing function for high output light, it is an optical reflection surface having a high reflection characteristic, or when used as an imaging function for a small output light, it is an optical reflection surface having non-reflection characteristics. Therefore, the light irradiation surface of the support member in the optical path is used as a surface that adapts to the characteristics of the reflected light, and there is an effect of having optimal conditions for the respective characteristics.

According to the third aspect of the invention, since the supporting member includes the minute displacement element for adjusting the optical axis with respect to at least one of the main reflecting mirror and the sub-reflecting mirror, the reflecting mirror is still in the assembled state. The optical axis can be adjusted, its position can be held, and high precision and high resolution can be achieved.

[Brief description of drawings]

FIG. 1 is a schematic vertical sectional view of an optical device according to an embodiment of the present invention.

FIG. 2 is a perspective view of a main part of an optical device according to the embodiment.

FIG. 3 is a partial perspective view of a support member of the embodiment.

FIG. 4 is a partial perspective view of a support member according to another embodiment.

FIG. 5 is a partial vertical cross-sectional view of a supporting member according to another embodiment.

[Explanation of symbols]

K ... Optical axis, 6 ... Translucent part, 4 ... Main reflecting mirror, 10 ... Sub-reflecting mirror, 1 ... Lens barrel, 2 ... Support member, 20 ... Piezoelectric element, 11a
… Shape memory alloy, 22… High temperature heater.

Claims (7)

[Claims] 1. A main reflecting mirror comprising a large-diameter concave mirror having a light transmitting portion along the optical axis, and a small-diameter convex mirror arranged on the optical axis so as to face the main reflecting mirror. Equipped with a sub-reflector, the incident light from the surroundings of the sub-reflector to the main reflector or from the translucent part of the main reflector to the sub-reflector is reflected by the main reflector and the sub-reflector. In the optical device for reducing or expanding the luminous flux, a lens barrel that houses the main reflecting mirror and the sub-reflecting mirror therein, and a main reflecting mirror and a sub-reflecting mirror for the lens barrel A supporting member that is supported at a position and has a rectangular cross section with respect to the light traveling direction, and the rectangular cross section of the supporting member has a width facing the light traveling direction from a width parallel to the light traveling direction. An optical device characterized by being formed narrower. 2. A reflection surface having a high reflection characteristic when it is used in the optical path of the support member and has a narrow width facing the traveling direction of the light when it is used for condensing light of high output. Claim 1 characterized in that
The described optical equipment. 3. A reflection surface having a non-reflective property when used as an image forming function of light of small output, which is located in the optical path of the support member and has a narrow width facing the traveling direction of light. Claim 1 characterized in that
The described optical equipment. 4. A main reflecting mirror comprising a large-diameter concave mirror having a light transmitting portion along the optical axis, and a small-diameter convex mirror arranged on the optical axis so as to face the main reflecting mirror. Equipped with a sub-reflector, the incident light from the surroundings of the sub-reflector to the main reflector or from the translucent part of the main reflector to the sub-reflector is reflected by the main reflector and the sub-reflector. In the optical device for reducing or expanding the luminous flux, a lens barrel that houses the main reflecting mirror and the sub-reflecting mirror therein, and a main reflecting mirror and a sub-reflecting mirror for the lens barrel An optical device, comprising: a support member that is supported at a position, wherein the support member includes a minute displacement element that adjusts an optical axis of at least one of a main reflection mirror and a sub reflection mirror. 5. The optical device according to claim 4, wherein at least one of a piezoelectric element, a photostrictive element, and a magnetostrictive element is used as the minute displacement element. 6. The optical device according to claim 4, wherein the micro-displacement element comprises a shape memory alloy and a high-temperature heater arranged around the shape memory alloy. 7. The optical apparatus according to claim 4, wherein the support member is provided with displacement amount detecting means.