JPH10221596A - Floating follow-up optical system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a floating follow-up optical system with simple mechanism which suppresses displacement between optical axes within a tolerance and restrain chromatic aberration from generating, by optically correcting at least one of parallel moving components or gradient components between two optical axes even if mechanical displacement between optical axes is generated by relative displacement of plural optical systems. SOLUTION: This system consists of a first afocal optical system AFC1 belonging to a floating system and a second afocal optical system AFC2 belonging to a fixed system. The first afocal optical system AFC1 has first and second thin lenses L1, L2, and the second afocal system AFC2 has third and forth thin lenses L3, L4. The first and second afocal optical systems AFC1, AFC2 are designed to satisfy gradient follow-up conditions.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is applicable to optical devices in general, and in particular, automatically eliminates mechanical displacement between optical axes due to relative displacement of a plurality of optical systems and emits light. The present invention relates to a floating tracking optical system that guides light in a predetermined direction.

[0002]

2. Description of the Related Art Heretofore, as a system similar to this type of floating-following type optical system, the following prior art has been applied.

[0003] For example, Japanese Patent Application Laid-Open Nos. 50-80846 and 50-81161, and
The invention disclosed in Japanese Patent No. 1162 is configured to always form an optical image at a predetermined position on a film even when an optical system such as a camera is rotated and oscillated. According to such a configuration, when an optical system such as a camera is rotationally oscillated, the prism formed of a plano-concave lens and a plano-convex lens provided in the optical system is relatively displaced, thereby correcting the angle of the optical axis, that is, The inclination component of the optical axis is corrected. As a result, an optical image can be formed at the same position as before the optical system rotationally swings, so that the image forming position is stabilized (hereinafter, referred to as Conventional Technique 1).

Further, for example, the invention disclosed in Japanese Patent Application Laid-Open No. S51-40942 discloses that an optical image is always formed at a predetermined position on a film even when an optical system such as a camera rotates and swings. It is configured for purpose. According to such a configuration, when an optical system such as a camera rotates and swings,
The angle of the optical axis is corrected by shifting the pair of special transparent elements to each other in accordance with the tilt of the optical system. As a result, an optical image can be formed at the same position as before the optical system rotationally swings, so that the image forming position is stabilized (hereinafter, referred to as Conventional Technique 2).

Further, for example, the invention disclosed in Japanese Patent Application Laid-Open No. 1-142704 discloses a method of illuminating light incident on an exposure device from an illumination light source device even when the illumination light source device is installed separately from the exposure device. The purpose of the present invention is to eliminate the illumination spots and the waste of the illumination light on the wafer placed on the XYZθ table by correcting the axis shift. According to such a configuration, when the exposure apparatus swings back and forth and right and left in accordance with the operation of the XYZθ table arranged in the exposure apparatus, the first and the second axes provided in the optical axis adjustment apparatus are based on the swing angles. By moving and rotating the second mirror by a predetermined amount via a predetermined control system, it is possible to correct the optical axis shift of the illumination light incident on the exposure apparatus. As a result, it is possible to eliminate illumination spots on the wafer and waste of illumination light (hereinafter, referred to as conventional technology 3).

Further, for example, the invention disclosed in Japanese Patent Application Laid-Open No. 3-189710 is designed to instantaneously suppress the vibration induced by the air spring type vibration isolation table. According to such a configuration, when low-frequency vibration is induced in the air spring type vibration isolation table for the vertical X-ray exposure stage used in semiconductor manufacturing, the vibration is instantaneously controlled by a predetermined control system. Can be done. As a result, rapid exposure processing and high-accuracy mask patterns can be ensured (hereinafter, referred to as Conventional Technique 4).

Further, for example, the invention disclosed in Japanese Utility Model Laid-Open No. 58-40706 is designed to reflect light rays at an arbitrary angle. According to such a configuration, for example, when the angle between the A optical axis and the B optical axis changes, by adjusting the direction of the reflector, the light incident in the A optical axis direction is always changed to the B optical axis direction. (Hereinafter, referred to as conventional technology 5).

[0008]

However, the prior art 1 has the following problems.

First, it is impossible to correct the translation component of the optical axis shift.

In a normal camera, the stabilization of the imaging position can be sufficiently achieved only by the angle correction. However, since the displacement component of the optical system that relatively displaces includes the tilt component and the translation component, if the translation component is not corrected, the effective light flux decreases, that is, the so-called pupil shift or the like. There is a problem of causing a phenomenon such as pupil vignetting. That is, in an optical system that is relatively displaced, not only angle correction, that is, correction of the tilt component of the optical axis, but also correction of the translation component of the optical axis is required.

Second, there is only one degree of freedom in displacement of the system on the side of displacement.

That is, since the displacement component of the optical system that relatively displaces has a tilt component and a translation component, it should be configured to be able to translate in an arbitrary direction with an arbitrary point as the center of rotation. Needless to say, is structurally advantageous.

Third, chromatic aberration occurs.

According to the prior art, a prism composed of a plano-concave lens and a plano-convex lens is used in order to stabilize the image formation position. This is accompanied by not a little occurrence.

Fourth, the usable wavelength range is limited.

In the prior art, since the angle is corrected by the refraction of the prism, it can be used only in a wavelength range that can transmit the optical material.

Further, the prior art 2 is characterized in that angle correction is performed via a prism composed of a pair of special transparent elements.
There are the same problems as the first, third and fourth problems of the prior art 1. Further, the fifth conventional technique has, as a fifth problem, a problem that a control system for driving a pair of special transparent elements is separately required, so that the optical system is restricted to a certain extent. That is, the angle control resolution at the time of tilt correction,
Same angle control time response, same angle control time drift, etc.
It is determined by the above control system. Furthermore, since the pair of special transparent elements applied to the prior art has a special shape that is neither flat nor spherical, a general method of manufacturing lenses and prisms cannot be applied.
Therefore, the production of such an element requires a special numerically controlled polishing machine, which causes a problem that the production cost becomes extremely high. In addition, the prior art 3,4
Have the same problem as the above-mentioned fifth problem because all require a control system. Then, the conventional technology 5 has the same problem as the first problem.

The present invention has been made in order to solve such a problem, and an object of the present invention is to provide a case where a mechanical displacement of optical axes occurs due to a relative displacement of a plurality of optical systems. However, by simply optically correcting at least one of the translation component and the tilt component between the optical axes, it is possible to suppress the deviation between the optical axes within an allowable range and to suppress the occurrence of chromatic aberration. An object of the present invention is to provide a floating-following optical system having a configuration.

[0019]

In order to achieve the above object, a floating-following optical system according to the present invention comprises a fixed system having a mechanically fixed fixed optical axis, and at least one of the fixed systems belonging to the fixed system. At least one optical element, a floating system having a floating optical axis having at least one degree of freedom in mechanical movement with respect to the fixed system, and at least one optical element belonging to the floating system A first optical element to which light rays from the fixed system first enter belong to the floating system, and a last optical element to which light rays finally enter belong to the fixed system, and the first optical element When the N-th optical element counted from the element satisfies the relationship belonging to the fixed system when N is an even number and satisfies the relationship belonging to the floating system when N is an odd number, Displacement with respect to Even if the floating optical axis fluctuates arbitrarily with respect to the fixed optical axis, the light beam incident on the first optical element along the fixed optical axis belonging to the fixed system is always Emitted along the floating optical axis.

In the floating tracking type optical system according to the present invention, at least one afocal optical system is used as the optical element.

In the floating tracking type optical system according to the present invention, when at least two and an even number of a total of k afocal optical systems are used as the optical elements, they correspond to the first optical elements. The angular magnification of the first afocal optical system is γ1, the angular magnification of the Nth afocal optical system corresponding to the Nth optical element is γN, and the angular magnification of the kth afocal optical system corresponding to the final optical element is If the angular magnification is γk,

(Equation 2)

It is characterized in that at least one of the formulas (I-1) and (I-2) having the following relationship is satisfied.

Further, in the floating tracking type optical system according to the present invention, the optical system is composed of at least four or more optical elements, the power of the N-th optical element is φ _N , and the power of the N-th optical element is 'When, (e _1' the distance from the rear principal point to the front principal point of the first N + 1 optical element _{e N · φ 1 · φ 2} ) -φ 1 + (e 1 '+ e 2') φ 1 · φ ₃ − (e ₁ ′ ・ e ₂ ′ ・ φ ₁・ φ ₂・ φ ₃ ) −φ ₃ + φ ₄ = 0 (I-3) φ ₃ = (e ₁ ′ + e ₂ ′) ⁻¹ + (e ₃ ') ^-1 (I-4) φ ₄ =-(e ₁ ' + e ₂ '+ e ₃ ') ^-1 + (e ₃ ') ^-1 (I-5) 3) to (I-5), at least the formula (I-3) or the formula (I-
It is characterized by satisfying any one of 4) and (I-5).

As described above, in the floating tracking type optical system of the present invention, even if the floating optical axis fluctuates arbitrarily with respect to the fixed optical axis due to the displacement of the floating system with respect to the fixed system, it belongs to the fixed system. Light rays incident on the first optical element along the fixed optical axis are always emitted from the last optical element along the floating optical axis.

[0025]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the principle of the present invention will be described, and a floating-following optical system according to an embodiment of the present invention constructed based on this principle will be described with reference to the accompanying drawings. In the present invention, the fixed system is not necessarily limited to an optical system fixed to the ground or the like. For example, of the two optical systems that are relatively displaced, one optical system can be conveniently defined as a fixed system, and the other optical system can be conveniently defined as a floating system.

Further, it is not necessary that the incident light beam incident on the floating follow-up type optical system of the present invention coincides with the optical axis of the fixed system (hereinafter, referred to as a fixed optical axis). For example, when the optical axis of the floating system (hereinafter, referred to as the floating optical axis) is relatively displaced from the fixed optical axis, even if the incident light does not coincide with the fixed optical axis, the displacement component of the floating system Of these, at least one of the translation component and the tilt component is optically corrected in the paraxial region, so that the optical axis deviation between the fixed optical axis and the floating optical axis is within an allowable range. Can be suppressed. Further, if various aberrations are corrected sufficiently for light around the fixed optical axis and the floating optical axis (hereinafter, referred to as off-axis light), and the various aberrations are suppressed to an allowable range, In the same manner as described above, it is possible to optically suppress the deviation between the optical axes between the fixed optical axis and the floating optical axis within an allowable range, and to favorably image off-axis light.

That is, in the floating-following optical system of the present invention, by appropriately determining the power, the angular magnification, and the arrangement of each optical element (group) constituting the plurality of optical systems, the light beam emitted from the fixed system is Depending on each optical element (group),
It will be refracted or reflected or diffracted. As a result, even if the optical axis of the fixed system and the optical axis of the floating system are mechanically displaced from each other, at least one of the translation component and the tilt component is optically corrected to allow the displacement between the optical axes. It can be suppressed within the range.

Hereinafter, an optical system model, a symbol, a coordinate system, and terms used in this specification will be described.

First, the optical system model will be described with reference to the thin lens model shown in FIG. In this thin lens model, a fixed system (not shown)
It is assumed that the optical system is a mechanically fixed optical system, and the floating system (not shown) is an optical system having at least one degree of freedom with respect to mechanical movement with respect to the fixed system. The thin lens model is configured to optically connect the fixed system and the floating system.

FIG. 1 shows a state in which the fixed optical axis of the fixed system and the floating optical axis of the floating system are overlapped, and a dashed line in the figure is formed by the overlapping of the fixed optical axis and the floating optical axis. 2 shows a common optical axis A.

As shown in FIG. 1, the thin lens model is
It is composed of j thin lenses (j: natural number) arranged along the optical axis A, and a floating system and a fixed system are formed by these thin lenses.

L ₁ is a thin lens (hereinafter, referred to as a first lens) on which a light beam first enters among a plurality of thin lenses belonging to a floating system.
Lens referred to as) indicates, and, L _n is, n-th counted from the first lens (n; showing a thin lens of a natural number) (hereinafter, referred to as the n-th lens). _Lj indicates a thin lens (hereinafter, referred to as a final lens) on which a light ray enters last among a plurality of thin lenses belonging to the fixed system.

For a plurality of thin lenses satisfying the relationship of L _n (2 ≦ n ≦ j−1), either a floating system or a fixed system can be arbitrarily selected as an optical system to which these lenses belong. is there.

[0034] Incidentally, e _n '(n; natural number) indicates a distance between the n-th lens L _n and the n + 1 lens L _{n + 1} (distance).

The coordinate system shown in FIG. 1 is a coordinate system belonging to a fixed system, and is defined by adding an angle θ to two-dimensional rectangular coordinates composed of an x-axis and a y-axis.

In this coordinate system, the x-axis extends parallel to the fixed optical axis, the right direction is positive in the drawing, and the y-axis extends perpendicular to the fixed optical axis. In the figure, the upward direction is positive and the angle θ is positive in the clockwise direction.

Accordingly, each of the intervals e _n 'takes a positive value along the direction of the arrow.

In such a configuration, the light beam incident on the first lens L ₁ along the positive direction of the x-axis sequentially passes through j thin lenses in the positive direction, and then passes from the final lens L _j to the x direction.
Inject along the positive direction of the axis.

The thin lens model is a general example corresponding to a paraxial tracking formula described later, and the definitions of the fixed system and the floating system are also convenient. For this reason, for example, the above-described thin lens model can be applied to two optical systems that are relatively displaced.

In the above thin lens model,
The definition of the incident direction of the light beam is for convenience. Thus, for example, even when a ray from the negative direction of the x-axis relative to the final lens L _j belonging to the fixed system is incident, it is possible to apply the above thin lens model.

Next, the optical system model will be described with reference to the afocal optical system model shown in FIG. 2 (that is, an optical system model having an infinite focal length). This afocal optical system model is positioned as a lower concept of the above-described thin lens model.

As shown in FIG. 2, the afocal optical system model is composed of k afocal optical systems (k: natural number) arranged along the optical axis A, similarly to the thin lens model described above. The floating system and the fixed system are formed by these afocal optical systems. The optical axis A applied to such an afocal optical system model
Is formed by overlapping a fixed optical axis and a floating optical axis, like the thin lens model described above.

AFC ₁ indicates an afocal optical system (hereinafter, referred to as a first afocal optical system) on which a light beam first enters, among a plurality of afocal optical systems belonging to a floating system, and AFC _N indicates And N-th (N; natural number) afocal optical systems counted from the first afocal optical system.

In this case, when N is an even number, it means an afocal optical system belonging to a fixed system, and when N is an odd number, it means an afocal optical system belonging to a floating system.

Further, AFC _K, among the plurality of afocal optical systems that belong to a fixed system, the afocal optical system which light rays incident on the end (hereinafter, referred to as final afocal optical system) showing a.

The coordinate system shown in FIG. 2 is a coordinate system belonging to a fixed system, and is defined by adding an angle に to two-dimensional orthogonal coordinates composed of an X axis and a Y axis.

In this coordinate system, the X axis extends parallel to the fixed optical axis, the right direction is positive in the drawing, and the Y axis extends perpendicular to the fixed optical axis. In the figure, the upward direction is positive and the angle Θ is positive in the clockwise direction.

In such a configuration, light rays incident on the _first afocal optical system AFC ₁ along the positive direction of the X-axis sequentially pass through the k afocal systems, and then pass through the final afocal optical system AFC _K. From along the positive direction of the X-axis.

Note that this afocal optical system model is
Similar to the thin lens model described above, this is a general example corresponding to a paraxial tracking formula described later, and the definitions of the fixed system and the floating system are also convenient. For this reason, for example, the afocal optical system model can be applied to two optical systems that are relatively displaced.

Further, similarly to the above thin lens model,
In this afocal optical system model, the definition of the incident direction of the light beam is for convenience. X For this reason, for example belonging to the fixed-line final afocal optical system AFC _K
The above-described afocal optical system model can be applied even when a light beam enters from the negative direction of the axis.

Next, the optical system model will be described with reference to the thin lens paraxial tracking model shown in FIGS.

As shown in FIGS. 3 and 4, this thin paraxial tracking model is composed of the thin lenses L _{1 to} L _{j of the} thin lens model (see FIG. 1).
5 shows the state of paraxial tracking. Note that FIG.
To have been shown configuration in which the thin lens L _n belonging to a floating system, also in FIG. 4, the thin lens L _n configuration is shown in the case of belonging to a fixed system.

In the thin paraxial tracking models shown in FIGS. 3 and 4, respectively, the first lens L ₁ has a predetermined incident angle α _1.
Is incident on the first lens L ₁ through the thin lens L
After sequentially passing through _{2 to} L _{n -1} (see FIG. 1), the light becomes a light ray 4 and enters the n-th thin lens L _n .

[0054] light 4 incident on the n-th thin lens L _n
, After injection becomes refracted ray 6 from the thin lens L _n, is incident on the (n + 1) th thin lens L _{n + 1.} The optical system to which the (n + 1) th thin lens L _{n + 1} belongs can be arbitrarily selected from either a floating system or a fixed system. ) To (E-5) are not affected.

In FIGS. 3 and 4, reference numeral FIX is used.
Denotes a fixed optical axis, and FL denotes a floating optical axis. Also,
Rays to be paraxial tracing, the position and inclination of the floating optical axis FL, the position of the n-th thin lens L _n, respectively, it is measured with respect to the fixed optical axis FIX.

Here, the conditions for forming the paraxial tracking formula are defined as follows.

[0057] The angle between the light beam 4 entering the thin lens L _n (see FIGS. 3 and 4) and the fixed optical axis FIX is defined as alpha _n.

[0058] refracted ray emitted from the thin lens L _n 6
(See FIGS. 3 and 4) and the fixed optical axis FIX make an angle α
_n '.

[0059] beam 4 defines a height between the intersection and the fixed optical axis FIX intersecting the thin lens L _n and h _n.

The height between the point where the floating optical axis FL intersects the first lens L ₁ and the fixed optical axis FIX is defined as y _b, and the height between the floating optical axis FL and the fixed optical axis FIX is defined as yb. Is defined as θ _b .

[0061] If the thin lens L _n belonging to a floating system, the height between the intersection of floating the optical axis FL to cross the thin lens L _n and the fixed optical axis FIX is defined as y _n.

[0062] of the thin lens L _n power - the is defined as φ _n.

Under such conditions, the paraxial tracking formula applied to the thin lens paraxial tracking model is configured as follows. _{α n '= α n + h} n φ n ... (E-1) [L when _n belongs to the stationary system] _{α n' = α n + (} h n -y n) φ n ... (E-2) [L If _n belongs to a floating system] _{α n + 1 = α n '} ... (E-3) h n + 1 = h n -e n' · α n '... (E-4) such paraxial tracing official , The thin lenses L _n , L
_{If j} belongs to the fixed system, equations (E-1) and (E-3)
And (E-4).

On the other hand, when the thin lenses L _n and L _j belong to a floating system, equations (E-2), (E-3) and (E-4) are used.

[0065] Therefore, the height y _n, the following formula (E-5)
It is represented as

[0066]

(Equation 3)

Next, the optical system model will be described with reference to the afocal optical system tilt model shown in FIGS.

As shown in FIGS. 5 and 6, the afocal optical system inclination model is obtained by using the afocal optical systems AFC _{1 to} AFC of the afocal optical system model (see FIG. 2).
It is composed of _K, and shows a state where the floating system is inclined with respect to the fixed system. FIGS. 5 and 6 show paraxial tracking states, respectively. FIG. 5 shows a configuration when the afocal optical system AFC _N belongs to the floating system, and FIG. 6 shows a configuration when the afocal optical system AFC _N belongs to the fixed system. I have.

In the afocal optical system tilt models shown in FIGS. 5 and 6, the light ray 8 incident on the first afocal optical system AFC ₁ at a predetermined incident angle A ₁ is the first type.
Afocal optical system AFC ₁ to Afocal optical system A
After passing through FC _{2 to} AFC _N-1 (see FIG. 2), light 1
0 when it is incident on the N-th afocal optical system AFC _N.

[0070] beam 10 incident on the n-th afocal optical system AFC _N, after injection becomes refracted ray 12 from the afocal optical system AFC _N, incident on the N + 1 th afocal optical system AFC N + ₁ And similarly refracted light 1
It will be 4 and it will eject.

In FIGS. 5 and 6, the symbol FIX is used.
Denotes a fixed optical axis, and FL denotes a floating optical axis. Also,
The inclination of the light beam to be subjected to paraxial tracking and the inclination of the floating optical axis FL are measured with reference to the fixed optical axis FIX.

Here, conditions for forming the paraxial tracking formula are defined as follows.

The angle between the light beam 10 (see FIGS. 5 and 6) incident on the afocal optical system AFC _N and the fixed optical axis FIX is defined as A _N.

The angle between the refracted light beam 12 (see FIGS. 5 and 6) emitted from the afocal optical system AFC _N and the fixed optical axis FIX is defined as A _N '.

[0075] defined as floating-optical axis FL and the fixed optical axis FIX and angle of theta _b, also defines the angular magnification of the afocal optical system AFC _N and gamma _N.

Under such conditions, the paraxial tracking formula applied to the afocal optical system tilt model is configured as follows. A _N '[when AFC _N belongs to fixed-line] _{= γ N A N ... (E} -6) A N' = γ N (A N -Θ b) + Θ b ... (E-7) [AF
C _N In the case belongs to a floating system] _{A N + 1 = A N '} ... (E-8) such paraxial tracking formula, if the afocal optical system AFC _N, AFC _K belongs to the stationary system, wherein (E-
6) and (E-8) are used.

On the other hand, the afocal optical system AFC
_N, AFC _K may belong to a floating system, using equation (E-7) and (E-8).

Next, the optical system model will be described with reference to the afocal optical system translation model shown in FIGS.

As shown in FIGS. 7 and 8, the afocal optical system parallel movement model is the same as the afocal optical system AFC _{1 to} AFC of the afocal optical system model (see FIG. 2).
It is composed of _K, and shows a state in which the floating system has moved parallel to the fixed system. 7 and 8 show paraxial tracking states, respectively. FIG. 7 shows a configuration when the afocal optical system AFC _N belongs to a floating system, and FIG. 8 shows a configuration when the afocal optical system AFC _N belongs to a fixed system. I have.

In the afocal optical system translation model shown in FIG. 7 and FIG. 8, the fixed optical axis FIX and the floating optical axis FL with respect to the first afocal optical system AFC ₁ , respectively.
Rays 16 incident parallel to A, the afocal optical system from the first afocal optical system AFC ₁ AFC ₂ ~AFC _N-1
After passing through the (see FIG. 2), enters the N-th afocal optical system AFC _N becomes light 18.

[0081] beam 18 incident on the n-th afocal optical system AFC _N, after injection becomes refracted ray 20 from the afocal optical system AFC _N, incident on the N + 1 th afocal optical system AFC N + ₁ And similarly refracted ray 2
It will be 2 and it will eject.

In FIGS. 7 and 8, reference numeral FIX is used.
Denotes a fixed optical axis, and FL denotes a floating optical axis extending in parallel with the fixed optical axis FIX. The positions of the light beam to be subjected to paraxial tracking and the position of the floating optical axis FL are measured with reference to the fixed optical axis FIX.

Here, conditions for forming the paraxial tracking formula are defined as follows.

The height between the light ray 18 (see FIGS. 7 and 8) incident on the afocal optical system AFC _N and the fixed optical axis FIX is defined as H _N.

The height between the refracted light beam 20 (see FIGS. 7 and 8) emitted from the afocal optical system AFC _N and the fixed optical axis FIX is defined as H _N '.

[0086] The height between the fixed optical axis FIX and floating the optical axis FL defined as Y _b, also afocal optical system AFC _N
Is defined as γ _N.

Under such conditions, the paraxial tracking formula applied to the afocal optical system translation model is configured as follows. ^{_{H N '= γ N -1 H}} N ... (E-9) [when AFC _N belongs to fixed-line] ^{_{H N' = γ N -1 (}} H N -Y b) + Y b ... (E-10)
In [AFC _N may belong to a floating system] _{H N + 1 = H N '} ... (E-11) such paraxial tracking formula, if the afocal optical system AFC _N, AFC _K belongs to the stationary system, Equation (E−
9) and (E-11) are used.

On the other hand, the afocal optical system AFC
_N, if the AFC _K belongs to a floating system, the formula (E-10)
And (E-11).

Here, regarding the optical system model applied in the specification of the present invention, terms such as “parallel movement follow-up”, “tilt follow-up”, and “perfect follow-up” are shown in FIG.
This will be described with reference to (a), (b), and (c).

FIG. 9A shows a state in which the floating optical axis FL is translated with respect to the fixed optical axis FIX by the parallel movement of the floating system with respect to the fixed optical system in the thin lens model. I have.

[0091] In the figure, the incident light beam 24 to the thin lens L ₁ which belongs to a floating system is incident coincides with the fixed optical axis FIX. Also, exit ray 26 from the thin lens L _j belonging to the fixed system is injected coincides with the floating optical axis FL. In such a model, the displacement amount of the parallel movement is arbitrary within the paraxial region.

This state is called “parallel movement tracking”, and the condition required for the optical system to realize the parallel movement tracking is called “parallel movement tracking condition”.

FIG. 9B shows a state in which the floating optical axis FL is tilted and displaced by a predetermined angle with respect to the fixed optical axis FIX due to the tilting displacement of the floating system with respect to the fixed system in the thin lens model. It is shown.

In the figure, the incident light beam 28 to the thin lens L ₁ belonging to the floating system is incident so as to coincide with the fixed optical axis FIX. Also, exit ray 30 from the thin lens L _j belonging to the fixed system is injected in parallel with a floating optical axis FL. In such a model, the amount of tilt displacement and the center of rotation are arbitrary within the paraxial region.

This state is called “tilt following”, and the condition required for the optical system to realize tilt following is called “tilt following condition”.

FIG. 9C shows a state in which the floating optical axis FL is tilted and displaced by a predetermined angle with respect to the fixed optical axis FIX due to the tilting of the floating system with respect to the fixed system in the thin lens model. It is shown.

[0097] In the figure, the incident light beam 32 to the thin lens L ₁ which belongs to a floating system is incident coincides with the fixed optical axis FIX. Also, exit ray 34 from the thin lens L _j belonging to the fixed system is injected coincides with the floating optical axis FL. In such a model, the amount of tilt displacement and the center of rotation are arbitrary within the paraxial region. This state is called “perfect following”, and the condition required for the optical system to realize perfect following is called “perfect following condition”.

Such parallel movement follow-up, tilt follow-up, complete follow-up and the like are collectively referred to as "float follow-up", and an optical system having a floating follow-up action is referred to as "float follow-up optical system".

The optical system models shown in FIGS. 9A, 9B, and 9C are configured so that the odd-numbered lenses belong to the floating system and the even-numbered lenses belong to the fixed system. However, it goes without saying that the second to j-1th lenses are not limited to the above-described configuration.

Although the above terms have been described using a thin lens system, other general optical systems (for example,
The same term can be applied to a thick lens system, a reflection optical system, a diffractive optical system, and an afocal optical system combining these.

Further, if the aberration correction for off-axis light is sufficiently considered when designing the optical system model, the amount of translational displacement and the amount of tilt displacement generated in the floating follow-up type optical system are not limited to the paraxial region. Needless to say.

Further, in the above description, the following condition is based on the condition that the emitted light beam and the tilt component or the parallel movement component of the floating optical axis coincide with each other. It suffices if they almost match with accuracy.

Here, when k = 2 in the afocal optical system model of FIG. 2, the behavior of the light beam in the afocal optical system tilt model of FIGS. 5 and 6 is analyzed.

The relationship of the light rays in the afocal optical systems AFC _{1 to} AFC ₂ is obtained by the above-mentioned equations (E-6) to (E-
Based on 8), it is defined as follows. A ₁ ′ = γ ₁ (A ₁ −Θ _b ) + Θ _b (E-12) A ₂ ′ = γ ₂ · A ₂ (E-13) A ₂ = A ₁ ′ (E-14) When solved, A ₂ ′ = γ ₂ ｛γ ₁ (A ₁ −Θ _b ) + Θ _b … (E−15).

Here, according to the definition of the inclination follow-up condition, A
And rearranging by substituting ₁ = 0 and A ₂ '= Θ _b the above formula (E-15), the ^{_{(γ 1 · γ 2) -1}} -γ 1 -1 + 1 = 0 ... (E-16) . The above equation (E-16) is a tilt following condition equation of the two afocal optical system models.

Next, when k = 3 in the afocal optical system model in FIG. 2, the behavior of light rays in the afocal optical system tilt model in FIG. 6 is analyzed. Here, however, unlike the arrangement of FIG. 6, the final afocal optical system AFC ₃ belongs to a floating system.

In this case, the afocal optical system AFC _1-
Relationship of the rays in the AFC ₂ is the same as the above formula (E-15).

[0108] The relationship of the rays in the final afocal optical system AFC ₃ based on the above-mentioned formula (E-7), the _{A 3 '= γ 3 (A} 3 -Θ b) + Θ b ... (E-17) . Here, the above-described equations (E-15) and (E-1)
7), A ₃ ′ = γ ₃ [γ ₂ ｛γ ₁ (A ₁ −Θ _b ) + Θ _b ｝ −Θ _b ] + Θ _b (E-18)

Here, according to the definition of the inclination follow-up condition, A
Substituting ₁ = 0 and A ₃ ′ = Θ _b into the above equation (E-18) and rearranging, the slope following condition becomes (γ ₁ · γ ₂ ) ⁻¹ −γ ₁ ⁻¹ + 1 = 0. This is the same as the equation (E-16). This final afocal optical system AFC _3, which means that it does not contribute to the tilt tracking operation of the optical system model.

Next, when k = 4 in the afocal optical system model of FIG. 2, the behavior of the light beam in the afocal optical system tilt model of FIGS. 5 and 6 is analyzed.

Also in this case, when the same induction as in the case of k = 2 and k = 3 is performed, (γ ₁ γ ₂ γ ₃ γ ₄ ) ⁻¹ − (γ ₁ γ ₂ γ ₃ ) ⁻¹ + (γ ₁ · γ ₂ ) ⁻¹ −γ ₁ ^-1 + 1 = 0 (E-19) Note that the above equation (E-19) is a tilt following condition equation for the four afocal optical system models.

Next, when k = 5 in the afocal optical system model in FIG. 2, the behavior of light rays in the afocal optical system tilt model in FIGS. 5 and 6 is analyzed.

Also in this case, when the same guidance as in the case of k = 2 to 4 described above is performed and the inclination following condition equation is obtained, the same result as the above equation (E-19) is obtained.

As described above, in each of the above-described optical system models formed by connecting an arbitrary number of afocal optical systems, it is possible to obtain a tilt following condition formula.

Therefore, the general expression of the tilt following condition in the optical system model is as follows:

(Equation 4)

Is obtained. Note that an even number of afocal optical systems is effective as a setting condition of the above equation (I-1).

Next, when k = 2 in the afocal optical system model of FIG. 2, the behavior of light rays in the afocal optical system translation model of FIGS. 7 and 8 is analyzed.

In this case, the afocal optical system AFC _1-
The relationship of the light rays in AFC ₂ is calculated by the above-mentioned equation (E-9).
Based on (E-11), it is defined as follows. H ₁ ′ = γ ₁ ⁻¹ (H ₁ −Y _b ) + Y _b (E-20) H ₂ ′ = γ ₂ ⁻¹ · H ₂ (E-21) H ₂ = H ₁ ′ (E− 22) By solving these, H ₂ ′ = γ ₂ ⁻¹ {γ ₁ ⁻¹ (H ₁ −Y _b ) + Y _b } (E-23)

Here, H ₁ = 0 and H ₂ ′ = Y _b are substituted into the above equation (E-23) and rearranged according to the definition of the parallel movement follow-up condition, and γ ₁ · γ ₂ -γ ₁ + 1 = 0 (E-24). The above equation (E-24) is a parallel movement tracking condition equation of the two afocal optical system models.

Next, when k = 3 in the afocal optical system model of FIG. 2, the behavior of light rays in the afocal system translation model of FIG. 8 is analyzed. Here, however, unlike the arrangement of FIG. 8, the final afocal optical system AFC ₃ belongs to a floating system.

Here, the same guidance as in the case of k = 2 described above is performed to obtain the parallel movement follow-up conditional expression.
-24). This final afocal optical system AFC _3, which means that it does not contribute to the translation follow the action of the optical system model.

Next, when k = 4 in the afocal optical system model of FIG. 2, the behavior of light rays in the afocal optical system translation model of FIGS. 7 and 8 is analyzed.

Also in this case, when the same induction as in the case of k = 2 and k = 3 is performed, (γ ₁ γ ₂ γ ₃ γ ₄ ) − (γ ₁ γ ₂ γ ₃ ) + (Γ ₁ · γ ₂ ) −γ ₁ + 1 = 0 (E-25) The above equation (E-25) is a parallel movement tracking condition equation for the four afocal optical system models.

Next, when k = 5 in the afocal optical system model of FIG. 2, the behavior of light rays in the afocal optical system translation model of FIGS. 7 and 8 is analyzed.

Also in this case, by performing the same guidance as in the case of k = 2 to 4 described above and finding the parallel movement following condition,
The same result as the above equation (E-25) is obtained.

As described above, in the above-described optical system model in which an arbitrary number of afocal optical systems are connected in series, it is possible to obtain the parallel movement following condition.

Therefore, the general expression of the parallel movement following condition in the above optical system model is as follows:

(Equation 5)

Is as follows. Note that an even number of afocal optical systems is effective as a setting condition of the above equation (I-2).

Here, a condition that simultaneously satisfies the above equations (I-1) and (I-2) is derived.
The values of ₁ and γ ₂ are imaginary solutions. When k ≧ 4, the value of γ _N (N = 1 to k) is a real solution. That is, k = 2
, It is possible to satisfy either the tilt following condition or the parallel movement following condition, and when k ≧ 4,
Both conditions can be satisfied simultaneously.

Next, in the thin lens model of FIG.
When = 4, the behavior of the light ray in the thin lens model paraxial tracking model of FIGS. 3 and 4 is analyzed.

First, the following condition is set as the displacement of the floating system. θ _b ≠ 0, y _b = 0 (E-26) In addition, the following condition is set for the incident light. h ₁ = α ₁ = 0 (E-27) These conditional expressions (E-26) and (E-27) are substituted into the paraxial tracking formulas (E-1) to (E-4) described above. By sequentially guiding the refracted light rays over the thin lenses L _{1 to} L ₄ , the refracted light rays from the thin lens L ₃ are defined as follows. _{α 4 = α 3 '= -y} 3 · φ 3 ... (E-28) h 4 = e 3' · y 3 · φ 3 ... (E-29) The refractive light from the thin lens L _1, the following It is defined as follows. α ₄ '= y ₃ · φ ₃ (e ₃ ' · φ ₄ -1) (E-30) Here, under the conditions shown by the above equations (E-26) and (E-27), the emission light, refracted ray from thin lens L ₄ is a condition for matching the floating optical axis is _{α 4 '= θ b ... (} E-31) h 4 = y 4 ... (E-32).

In this case, the above equations (E-28) to (E-3)
Solving the simultaneous equations consisting of 2) and the equation (E-5), it is found that the emission light coincides with the floating optical axis based on the conditions set by the above equations (E-26) and (E-27). A conditional expression is derived. That is, if the induction process is omitted and only the result is described, φ ₃ = (e ₁ ′ + e ₂ ′) ⁻¹ + (e ₃ ′) ^-1 (I-4) φ ₄ = − (e ₁ '+ E ₂ ' + e ₃ ') ^-1 + (e ₃ ') ^-1 (I-5).

Formulas (I-4) and (I-
An optical system model that satisfies 5) satisfies the tilt following condition.

Next, the following condition is set as the amount of displacement of the floating system. θ _b = 0, y _b ≠ 0 (E-33) The incident light beam is set to the same condition as the above equation (E-27).

The above conditional expression (E-33) is expressed by the above expression (E
-27) together with the paraxial tracking formula (E-1) to
Substituting into (E-4) and sequentially guiding the refracted light rays over the thin lenses L _{1 to} L ₄ , the refracted light rays from the thin lens L ₃ are defined as follows. α ₄ = α ₃ ′ = y _b ｛−φ ₁ −φ ₃ + (e ₁ ′ ・ φ ₁・ φ ₂ ) + (e ₁ ′ ・ φ ₁・ φ ₃ ) + (e ₂ ′ ・ φ ₁・ φ ₃ ) − (e ₁ ′ · e ₂ ′ · φ ₁ Φ ₂ Φ ₃ )｝… (E-34) h ₄ = y _b ｛(e ₁ ′ · Φ ₁ ) + (e ₂ ′ · Φ ₁ ) + (E ₃ ′ · φ ₁ ) + (e ₃ ′ · φ ₃ ) − (e ₁ ′ ・ e ₂ ′ ・ φ ₁・ φ ₂ ) − (e ₁ ′ ・ e ₃ ′ ・ φ ₁・ φ ₂ ) − (E ₁ ′ ・ e ₃ ′ ・ φ ₁・ φ ₃ ) − (e ₂ ′ ・ e ₃ ′ ・ φ ₁・ φ ₃ ) + (e ₁ ′ ・ e ₂ ′ ・ e ₃ ′ ・ φ ₁・φ ₂ · φ ₃ )｝ (E-35) Further, the refracted light beam from the thin lens L ₄ is defined as follows. α ₄ ′ = y _b ｛(−φ ₁ −φ ₃ + (e ₁ ′ ・ φ ₁・ φ ₂ ) + (e ₁ ′ ・ φ ₁・ φ ₃ ) + (e ₁ ′ ・ φ ₁・ φ ₄ ) + (E ₂ '· φ ₁ · φ ₃ ) + (e ₂ ' · φ ₁ · φ ₄ ) + (e ₃ '· φ ₁ · φ ₄ ) + (e ₃ ' · φ ₃ · φ ₄ )-( e ₁ ′ ・ e ₂ ′ ・ φ ₁・ φ ₂・ φ ₃ ) − (e ₁ ′ ・ e ₂ ′ ・ φ ₁・ φ ₂・ φ ₄ ) − (e ₁ ′ ・ e ₃ ′ ・ φ ₁・ φ ₂・ φ ₄ )-(e ₁ ′ ・ e ₃ ′ ・ φ ₁・ φ ₃・ φ ₄ ) − (e ₂ ′ ・ e ₃ ′ ・ φ ₁・ φ ₃・ φ ₄ ) + (e ₁ ′ ・ e ₂ ′ · e ₃ ′ · φ ₁ · φ ₂ · φ ₃ · φ ₄ ) Ｅ (E-36) Here, under the conditions set by the above equations (E-27) and (E-33), The condition for following the movement, that is, the condition for the emitted light beam to coincide with the floating optical axis is as follows: α ₄ ′ = θ _b = 0 (E-37) h ₄ = y ₄ = y _b (E-38) It is.

In this case, the above equations (E-34) to (E-3)
8) and solving the simultaneous equations consisting of equation (E-33),
Under the conditions set by the above equations (E-27) and (E-33), a conditional equation for the emitted light to follow the parallel movement is derived. That is, by omitting the induction course, when referred to a result _{only, (e 1 '· φ 1} · φ 2) -φ 1 + (e 1' + e 2 ') φ 1 · φ 3 - (e 1' · e ₂ ′ · φ ₁ · φ ₂ · φ ₃ ) −φ ₃ + φ ₄ = 0 (I-3)

The optical system model that satisfies the formula (I-3) derived as described above satisfies the parallel movement tracking condition.

A condition that simultaneously satisfies the above equations (I-3) to (I-5) includes a real number solution. The optical system model in this case satisfies the perfect following condition.

In the above description, a case has been described in which the analysis and follow-up condition formulas are derived for a thin lens model of j = 4. Similar analysis and formula derivation are also performed for a thin lens model of j ≧ 5. It is possible to derive parallel movement following conditions, tilt following conditions, and perfect following conditions.

Further, in the case of a thick lens system, a reflective optical system, and a diffractive optical system, similar to the case of the thin lens model, by creating a paraxial tracking model, the parallel movement tracking condition and the tilt tracking condition can be obtained. Needless to say, it is possible to derive a perfect tracking condition.

Incidentally, the floating follow-up type optical system of the present invention
Among the lenses (groups) belonging to the floating system, the optical system starts with the lens (group) where the light beam enters first, and ends with the lens (group) where the light beam exits last among the lenses (group) belonging to the fixed system. is there.

When any optical system is added to the floating-following optical system, even if the added position is in front of the first lens (group) (in this case, all the added optical systems belong to the fixed system). Even in the rear side of the final lens (group) (in this case, all the added optical systems belong to the floating system), the floating follow-up action is not essentially affected by the added optical system.

This means that the afocal optical system AFC ₃ belonging to the floating system as the final lens (group) in the model of K = 3 in the derivation process of the above equations (I-1) and (I-2) It is clear from the fact that the floating following action was not affected at all.

Even when an optical system configured as a certain type of system is added to the floating tracking type optical system of the present invention, it goes without saying that the optical system effectively functions as a system. In addition, as such an optical system,
For example, in the following eleventh to sixteenth embodiments,
An optical system added before and after the floating tracking type optical system corresponds to this.

Next, a description will be given, with reference to FIG. 10, of a floating-following optical system according to the first embodiment of the present invention constructed on the basis of the above-described principle.

As shown in FIG. 10, the floating-following optical system according to the present embodiment comprises a first afocal optical system AFC ₁ belonging to a floating system and a second afocal optical system AFC ₂ belonging to a fixed system. It is composed of

The first afocal optical system AFC ₁ is constituted by first and second thin lenses L ₁ and L ₂ , and the second afocal optical system AFC ₂ is constituted by third and _second lenses. Four thin lenses L ₃ and L ₄ .

The first to fourth thin lenses L ₁ , L ₁ ,
The specifications of the first and second afocal optical systems AFC ₁ and AFC ₂ composed of L ₂ , L ₃ and L ₄ are shown in Table 1 below.

[0149]

[Table 1]

The first and second afocal optical systems AFC ₁ and AFC ₂ based on the specifications in Table 1 are designed so as to satisfy the above-mentioned equation (I-1), that is, the condition for following the inclination. I have.

Next, the operation of this embodiment will be described.

FIG. 10 shows a paraxial tracking result in the case where the floating optical axis FL is tilted and displaced with respect to the fixed optical axis FIX in the floating tracking optical system according to the present embodiment.

As shown in FIG. 10, the incident light ray 36 incident on the _first thin lens L1 coincident with the fixed optical axis FIX.
After passing through the second and third thin lenses L ₂ and L ₃ , the light exits from the fourth thin lens L ₄ as an emission ray 38 parallel to the floating optical axis FL.

In the figure, the first and second thin lenses L ₁ and L ₂ are respectively arranged in parallel with the y-axis, but actually, the first and second thin lenses L ₁ and L ₂ are arranged in parallel.
_{Since 1} and L ₂ are arranged orthogonal to the floating optical axis FL,
It is inclined with respect to the y-axis. Further, as defined in FIG. 3, the height y _b between the intersection of floating the optical axis FL is crossing first the thin lens L ₁ and the fixed optical axis FIX, and floating the optical axis FL fixed optical axis FIX Is defined as θ _b , FIG. 10 shows the floating optical axis F with respect to the fixed optical axis FIX.
When the displacement of L is y _b = 1 (mm), θ _b = 0.02 (r
ad) is shown.

In such a state, the emitted light beam 38
Are emitted at the same inclination as the floating optical axis FL. This is the only thing that the floating following optical system of the present embodiment satisfies the above expression (I-1).

In the present embodiment, the above y _b
And the value of θ _b become a value other than the above,
However, it goes without saying that the inclination is the same as the floating optical axis FL. As described above, according to the present embodiment, a floating tracking type optical system that satisfies the tilt tracking condition can be realized. Therefore, even if the floating system tilts with respect to the fixed system, the same tilt as the tilt is always obtained. It is possible to obtain the emitted light having the above.
As a result, it is possible to provide a floating-following optical system having a simple configuration capable of suppressing the deviation between the optical axes within an allowable range.

The floating-following optical system according to the present embodiment is effective when applied to an apparatus that needs to maintain a high beam tilt accuracy. An example of the system is described in a fifteenth embodiment described later. Show.

In this embodiment, the description has been made using the thin lens model. For example, the lens type is a thick single lens, an achromatic lens, an apochromatic lens, an isoplanatic lens, an aplanatic lens, an anastigmatic lens. A lens or the like is applicable.

As the lens form of the present embodiment, for example, a spherical lens, an aspherical lens, a refractive index distribution type lens, a composite structure type lens of optical glass and an optical resin, and the like can be applied. With such a configuration, it is possible to suppress various aberrations within an allowable range.

Incidentally, such a lens type and a lens form can be arbitrarily selected according to the degree of aberration correction required for the optical system.

Further, as the lens material of the present embodiment, for example, optical glass, optical resin materials such as polycarbonate, acrylic resin and styrene resin, quartz, quartz, calcite, sapphire (Al ₂ O ₃ ), fluoride Calcium (CaF ₂ ), sodium fluoride (NaF), lithium fluoride (LiF), potassium iodide (KI), cesium iodide (CsI), zinc sulfide (ZnS), zinc selenide (ZnSe), As ₂ S ₃ glass, Se (As) glass, silicon (Si), germanium (Ge), sodium chloride (NaCl), silver chloride (AgCl), indium-antimony (InSb), titanium dioxide (TiO)
₂ ), strontium titanate (SrTiO ₃ ), magnesium oxide (MgO), potassium bromide (BrK) and the like can be used.

Incidentally, regarding such a lens material,
It can be arbitrarily selected according to the wavelength range of the target light beam.

The lens material is about 200 nm.
It covers a wavelength in the range of μ25 μm, especially in the ultraviolet region, for example, using quartz, calcium fluoride, lithium fluoride, in the visible region, for example, using optical glass, in the infrared region, For example, it is preferable to use zinc sulfide, zinc selenide, germanium, silicon, and sapphire.

Next, a floating tracking optical system according to a second embodiment of the present invention will be described with reference to FIG.

As shown in FIG. 11, the floating-following optical system according to the present embodiment comprises a first afocal optical system AFC ₁ belonging to a floating system and a second afocal optical system AFC ₂ belonging to a fixed system. It is composed of

The first afocal optical system AFC ₁ converts a first concave mirror 42 having an opening 42a through which an incident light beam 40 is formed and an incident light beam 40 having passed through the opening 42a of the first concave mirror 42 into a first light. A second concave mirror 44 having an opening 44a for reflecting light in the direction of the first concave mirror 42 and passing light rays reflected from the first concave mirror 42;

The second afocal optical system AFC ₂ includes a third concave mirror 46 having an opening 46 a for transmitting a light beam passing through the opening 44 a of the second concave mirror 44, and an opening of the third concave mirror 46. And a convex mirror 48 for reflecting the light beam passing through 46a in the direction of the third concave mirror 46.

FIG. 11 shows the floating optical axis FL and the fixed optical axis FIX so as to match each other.

Further, the first and second afocal optical systems AFC ₁ and AFC ₂ applied to the present embodiment respectively satisfy the above formula (I-1) or the above formula (I-2). It is designed to be.

The first to third concave mirrors 42, 4
4, 46 and the respective reflecting surfaces 42b, 44 of the convex mirror 48
b, 46b and 48b are manufactured so as to have high reflectance in the wavelength range of the incident light beam 40.

Next, the operation of the present embodiment will be described.

As shown in FIG. 11, when a light beam emitted from a light source provided in a fixed system (not shown) is applied to the _first afocal optical system AFC1, the light beam applied to the first concave mirror 42 The incident light 40 incident from the opening 42a of the first concave mirror 42 is reflected from the reflection surface 44b of the second concave mirror 44, and then reflected by the reflection surface 42 of the first concave mirror 42.
b.

At this time, the reflection surface 42 of the first concave mirror 42
b reflected by the aperture 44a of the second concave mirror 44
After that, the light is emitted to the _second afocal optical system AFC2.

The light beam that has passed through the opening 44a of the second concave mirror 44 and emitted to the _second afocal optical system AFC2 passes through the opening 46a of the third concave mirror 46, and then is reflected by the reflection surface 48b of the convex mirror 48. Is irradiated.

The light beam applied to the reflecting surface 48b of the concave mirror 48 is reflected from the reflecting surface 48b and then reflected from the reflecting surface 46b of the third concave mirror 46 to become an outgoing light beam 50, which is the second light beam. It is emitted from the afocal optical system AFC _2.

In this case, when the first and second afocal optical systems AFC ₁ and AFC _{2 respectively} satisfy the above expression (I-1), the floating follow-up type optical system of the present embodiment will The following condition is satisfied.

When the first and second afocal optical systems AFC ₁ and AFC _{2 respectively} satisfy the above expression (I-2), the floating follow-up optical system of the present embodiment will The following condition is satisfied.

As described above, when the floating tracking type optical system of the present embodiment satisfies the tilt tracking condition, even if the floating system tilts with respect to the fixed system, the emission having the same tilt as this tilt always occurs. A light beam 50 can be obtained.

When the floating tracking type optical system of the present embodiment satisfies the parallel movement tracking condition, even if the floating system moves parallel to the fixed system, the floating tracking type optical system always performs the same movement as the parallel movement. This makes it possible to obtain an exit light beam 50 that moves in parallel.

Furthermore, since the floating-following optical system of the present embodiment is composed of only the reflecting optical system, it is possible to eliminate chromatic aberration at all, and it is practically impossible to manufacture a refracting optical system. The configuration of the present embodiment can be applied also to the wavelength band from ultraviolet rays to X-rays (about 125 nm to 3 nm).

In the present embodiment, the first and third concave mirrors 42, 44, 46 and the convex mirror 4 constituting the first and second afocal optical systems AFC ₁ and AFC ₂ are described.
Although 8 is constituted by a front mirror having a reflection surface formed on the lens surface, it may be constituted by a back mirror having a reflection surface formed on the back surface of the lens as shown in FIG. 12, for example. FIG. 12 shows an afocal optical system AFC composed of a biconvex lens 52 and a biconcave lens 54. The biconvex lens 52 and the biconcave lens 54 each have a reflective surface on the lens back surface so as to form a back mirror. 52a and 54a are formed.

In such a configuration, the incident light 56
After transmitting through the biconvex lens 52, the reflected light 54a formed on the back surface of the biconcave lens 54 passes through the reflection surface 52a formed on the back surface of the biconvex lens 52 to become an exit light beam 58 from the afocal optical system. Be injected.

In this case, the incident light beam 56 is
a, 54a as well as the optical action when reflecting from
The convex surfaces 52b and 52c of the biconvex lens 52 and the biconcave lens 5
4 also undergoes a refraction effect when transmitting through the concave surface 54b.

As a result, the present modified example has an advantage that the degree of freedom in designing the afocal optical system is improved and an advantage that the aberration correction is facilitated.

Next, a floating tracking type optical system according to a third embodiment of the present invention will be described with reference to FIG.

As shown in FIG. 13, the floating-following optical system according to the present embodiment comprises a first afocal optical system AFC ₁ belonging to a floating system and a second afocal optical system AFC ₂ belonging to a fixed system. It is composed of

The first afocal optical system AFC ₁ reflects a first concave mirror 62 for reflecting an incident light beam 60 and a light beam reflected from the first concave mirror 62 toward the second afocal optical system AFC ₂ . And a second concave mirror 64.

The second afocal optical system AFC ₂ includes a convex mirror 66 for reflecting the light beam reflected from the second concave mirror 64.
And a third concave mirror 68 for reflecting the light beam reflected from the convex mirror 66.

In the present embodiment, the first to third concave mirrors 62, 64, 68 and the convex mirror 66 are arranged to be relatively eccentric under predetermined conditions.

FIG. 13 shows the floating optical axis FL and the fixed optical axis FIX so as to match each other.

Further, the first and second afocal optical systems AFC ₁ and AFC ₂ applied to the present embodiment respectively satisfy the above formula (I-1) or the above formula (I-2). It is designed to be.

The first to third concave mirrors 62, 6
4, 68 and the respective reflecting surfaces 62a, 64 of the convex mirror 66
a, 66a and 68a are manufactured so as to have high reflectance in the wavelength range of the incident light beam 60.

Next, the operation of this embodiment will be described.

As shown in FIG. 13, an incident light beam 60 emitted from a light source provided in a fixed system (not shown) and incident on the _first afocal optical system AFC ₁ is converted into a first concave mirror 62.
Is reflected from the reflecting surface 64a of the second concave mirror 64 in the direction of the _second afocal optical system AFC2.

The light beam reflected from the reflecting surface 64a of the second concave mirror 64 is reflected from the reflecting surface 66a of the convex mirror 66 and then reflected from the reflecting surface 68a of the third concave mirror 68 to become an exit light beam 70. The light is emitted from the _second afocal optical system AFC2. In this case, the first and second
When the afocal optical systems AFC ₁ and AFC ₂ satisfy the above expression (I-1), the floating following optical system of the present embodiment satisfies the tilt following condition.

When the first and second afocal optical systems AFC ₁ and AFC _{2 respectively} satisfy the above expression (I-2), the floating follow-up optical system of the present embodiment performs the parallel movement. The following condition is satisfied.

As described above, the floating-following optical system according to the present embodiment is constituted by two sets of afocal optical systems each having only a reflecting optical system. Therefore, the same effects as those of the second embodiment are obtained. Can be obtained.

Furthermore, in the floating tracking type optical system of the present embodiment, the first to third concave mirrors 62, 64, 68 and the convex mirror 66 are relatively eccentrically arranged based on predetermined conditions. , Each reflecting surface 62a, 64a, 66a, 68
It is sufficient that the diameter of a is approximately equal to the effective light beam diameter, and an opening for passing light rays (see the second embodiment) becomes unnecessary. As a result, it becomes possible to design an inexpensive and compact floating-following optical system compared to the second embodiment.

Next, a floating tracking optical system according to a fourth embodiment of the present invention will be described with reference to FIG.

As shown in FIG. 14, the floating-following optical system according to the present embodiment comprises a first afocal optical system AFC ₁ belonging to a floating system and a second afocal optical system AFC ₂ belonging to a fixed system. It is composed of

The first afocal optical system AFC ₁ is constituted by first and second thin lenses L ₁ and L ₂ , and the second afocal optical system AFC ₂ is constituted by third and _second lenses. Four thin lenses L ₃ and L ₄ .

Further, the first to fourth thin lenses L ₁ , L ₁ ,
The specifications of the first and second afocal optical systems AFC ₁ and AFC _{2 including} L ₂ , L ₃ and L ₄ are shown in Table 2 below.

[0203]

[Table 2]

The first and second afocal optical systems AFC ₁ and AFC ₂ based on the specifications in Table 2 are designed so as to satisfy the above-mentioned equation (I-2), that is, the parallel movement following condition. ing.

Next, the operation of this embodiment will be described.

FIG. 14 shows paraxial tracking results when the floating optical axis FL is displaced in parallel with respect to the fixed optical axis FIX in the floating following optical system of the present embodiment.

As shown in FIG. 14, the incident light beam 72 incident on the _first thin lens L1 coincident with the fixed optical axis FIX.
After passing through the second and third thin lenses L ₂ and L _3, is emitted from the fourth thin lens L ₄ as an emitted light beam 74 that matches the floating optical axis FL. Further, as defined in FIG. 3, the height y _b between the intersection of floating the optical axis FL is crossing first the thin lens L ₁ and the fixed optical axis FIX, and floating the optical axis FL fixed optical axis FIX Is defined as θ _b , the displacement of the floating optical axis FL with respect to the fixed optical axis FIX is represented by y _b = 2 (mm) and θ _b = 0 (ra).
The state which becomes d) is shown.

In such a state, the emitted light 74
Are emitted completely coincident with the floating optical axis FL. This is because the floating-following optical system according to the present embodiment uses the above equation (I-
It is nothing but satisfaction of 2).

Also, in the present embodiment, the above y _b
It is needless to say that the emission light beam 74 coincides with the floating optical axis FL even if the value of.

As described above, according to the present embodiment, a floating-following optical system that satisfies the parallel-following condition can be realized. It is possible to obtain the emitted light beam 74 that moves in parallel in the same manner as this parallel movement. As a result, it is possible to provide a floating-following optical system having a simple configuration capable of suppressing the deviation between the optical axes within an allowable range.

The present embodiment is effectively applied to an apparatus that needs to maintain high accuracy of the center position of a light beam.

In this embodiment, the description has been made using the thin lens model. In practice, however, it is important to note that the first and second embodiments can be applied to various lens types, lens shapes, and lens materials. This is the same as the embodiment.

Next, a floating tracking type optical system according to a fifth embodiment of the present invention will be described with reference to FIG.

As shown in FIGS. 15A and 15B, the floating-following optical system according to the present embodiment is composed of four afocal optical systems arranged along the traveling direction of an incident light beam. Specifically, a first afocal optical system AFC ₁ belonging to a floating system, a _second afocal optical system AFC ₂ belonging to a fixed system, and a third afocal optical system AFC belonging to a floating system ₃ and a fourth afocal optical system AFC ₄ belonging to the fixed system.

The first afocal optical system AFC ₁ is constituted by first and second thin lenses L ₁ and L ₂ , and the second afocal optical system AFC ₂ is constituted by third and _second lenses. Four thin lenses L ₃ and L ₄ . Further, the third afocal optical system AFC ₃ is constituted by fifth and sixth thin lenses L ₅ and L ₆ , and the fourth afocal optical system AFC ₄ is constituted by seventh and eighth thin lenses LFC. Are constituted by thin lenses L ₇ and L ₈ .

The first to eighth thin lenses L ₁ to L ₁
First to fourth afocal optical system AF comprising L ₈
The specifications of C _{1 to} AFC ₄ are shown in Table 3 below.

[0219]

[Table 3]

The first to fourth afocal optical systems AFC _{1 to} AFC ₄ based on the specifications in Table 3 satisfy both the above-mentioned expressions (I-1) and (I-2). It is designed to be. In this case, the angular magnification γ _N is, for example, negative, positive, negative,
It has a positive value.

According to the _{first to fourth} afocal optical systems AFC _{1 to} AFC ₄ , both the inclination follow-up condition and the parallel movement follow-up condition can be satisfied, and each afocal optical system AFC ₁ can be satisfied. By properly setting the distance e _n ′ between the AFCs ₄ , the perfect following condition can be satisfied.

[0220] described herein, a method for determining the distance e _{n '4} between the first to fourth afocal optical system AFC ₁ ～AFC properly (interval setting method) for.

Now, each of the afocal optical systems AFC _{1 to} AFC
When the specifications of the floating tracking type optical system composed of FC ₄ are as shown in Table 4 below,

[Table 4]

The angular magnification γ _N of the floating follow-up type optical system satisfies both the above-mentioned equations (I-1) and (I-2).

At this time, the displacement of the floating optical axis FL with respect to the fixed optical axis FIX is y _b = 2 (mm), θ _b = 0 (ra
If a d) (translation state), at its paraxial tracking result, as shown in FIG. 16 (a), incident light incident on the first thin lens L ₁ coincides with the fixed optical axis FIX 76
After passing through the _{second to seventh} thin lenses L _{2 to} L ₇ ,
Injection becomes exit ray 78 that match a thin lens L ₈ to floating the optical axis FL of. This is the only condition that satisfies Expression (I-2), that is, the condition for following the parallel movement.

Next, the floating optical axis F with respect to the fixed optical axis FIX
When the displacement amount of L is y _b = 0 (mm), θ _b = 0.01 (r
ad) (in the inclined movement state), the paraxial tracking result indicates that the outgoing light beam 78 as shown in FIG.
Emit in the same inclination direction as the floating optical axis FL. This is nothing but the satisfaction of the equation (I-1), that is, the condition of inclination follow-up. However, in this case, the exit ray 78 and the floating optical axis F
L is relatively shifted in the y direction by about 1.5 (mm).

As a result, it is understood that the perfect following condition cannot be obtained only by satisfying both the above-mentioned equations (I-1) and (I-2).

Therefore, for example, e ₄ ′ in Table 4 (4th
When the value of the distance (interval) between the thin lens L ₄ and the fifth thin lens L ₅ is changed from 15.00 to 4.08 (see Table 3), the paraxial tracking result in the above-mentioned tilt movement state is obtained. Is the same as FIG. As a result, the incident light beam 76 that coincides with the fixed optical axis FIX becomes an emission light beam 78 that completely coincides with the floating optical axis FL, and is emitted from the floating following optical system.

As described above, in the floating following optical system composed of the _{first to fourth} afocal optical systems AFC _{1 to} AFC ₄ , each of the afocal optical systems AFC _{1 to} AF
The angular magnification γ _{N of} C ₄ satisfies both the formulas (I-1) and (I-2), and each afocal optical system AFC ₁ to
By optimizing the distance e _n ′ between AFCs ₄ ,
It is possible to obtain a perfect following condition. Note that, even when a floating tracking type optical system including six or more afocal optical systems is set, the same operation and effect as described above can be realized by applying the above-described interval setting method.

Next, the operation of this embodiment to which the above-described interval setting method is applied will be described.

FIGS. 15A and 15B show paraxial tracking results when the floating optical axis FL is displaced with respect to the fixed optical axis FIX in the floating tracking optical system according to the present embodiment. Have been.

[0230] FIG. 15 (a), the (b), the first thin lens L ₁ incident light 76 incident on coincides with the fixed optical axis FIX is thin lens of second to 7 L ₂ after a ~L _7, injects become exit ray 78 that matches the floating optical axis FL from thin lens L ₈ of the eighth.

In the figure, the first and second thin lenses L ₁ and L ₂ and the fifth and sixth thin lenses L ₅ and L ₆ are arranged in parallel with the y axis. Actually, these thin lenses L ₁ , L ₂ , L ₅ , L ₆ are arranged orthogonal to the floating optical axis FL, and therefore, are inclined with respect to the y axis.

Further, as defined in FIG. 3, the height between the point where the floating optical axis FL intersects the first thin lens L ₁ and the fixed optical axis FIX is y _b , and the height between the floating optical axis FL and the fixed optical axis FL is fixed. If the angle between the optical axis FIX and the optical axis FIX is defined as θ _b , FIG.
In the floating-following optical systems shown in FIGS. 15A and 15B, the displacement of the floating optical axis FL with respect to the fixed optical axis FIX is as follows.

That is, in the embodiment of FIG. 15A, the displacement of the floating optical axis FL with respect to the fixed optical axis FIX is:
y _b = 0 (mm) and θ _b = 0.01 (rad).

On the other hand, in the embodiment of FIG. 15B, the displacement of the floating optical axis FL with respect to the fixed optical axis FIX is:
y _b = 2 (mm) and θ _b = 0.02 (rad).

In such a state, FIG.
As shown in (b), the outgoing light beam 78 has a floating optical axis F
The injection is performed in complete agreement with L. This is nothing but that the floating tracking optical system of the present embodiment satisfies the perfect tracking condition.

In the present embodiment, the above y _b
And the value of θ _b become a value other than the above,
However, it goes without saying that it completely matches the floating optical axis FL. As described above, according to the present embodiment, it is possible to realize a floating tracking type optical system that satisfies the perfect tracking condition. However, it is always possible to obtain the emitted light beam 78 having a fixed position and inclination with respect to the floating system.

The floating follow-up type optical system according to the present embodiment is effective when applied to a device that needs to maintain both the center position accuracy and the tilt accuracy of a light beam at a high level. This is shown in the tenth and eleventh embodiments, respectively.

Although the present embodiment has been described using a thin lens model, in fact, various applications are possible and effective according to the lens type, lens form, lens material, and the like. This is the same as in the first embodiment.

Further, in the above embodiment, the angular magnification γ _N is
In the order along the incident direction of the light rays, the negative, positive, negative, and floating-following optical systems having positive values have been described. However, as shown in Table 5 below, in order along the incident direction of the light rays, Positive,
Negative, negative, even when a floating-following optical system having a positive value and became angular magnification gamma _N, by applying the interval setting method, to realize the same effect as the above embodiment Can be.

[0240]

[Table 5]

FIGS. 17A to 17C show paraxial tracking results of the floating tracking optical system having the specifications shown in Table 5. FIG. 3A shows that y _b = 0 (mm) and θ _b = 0 (r
ad) (parallel movement state), the paraxial tracking result is shown. In FIG. 3B, y _b = 0 (mm), θ _b =
0.02 If the (rad) has been shown paraxial tracking result of (tilting movement state), also in FIG. (C) is, y _b = 2
(Mm), the paraxial tracking result in the case of θ _b = 0.02 (rad) (in the inclined movement state) is shown.

As is clear from FIGS. 17A to 17C, the emitted light beam 78 is emitted completely coincident with the floating optical axis FL. This is nothing but that the floating tracking optical system satisfies the perfect tracking condition. In addition, in addition to the above setting conditions, the angular magnification γ _N is, in the order along the incident direction of the light ray, positive, negative, positive, negative, or negative, positive, positive, negative value is the same as above. The function and effect can be realized. The other operation and effect are the same as those of the above-described embodiment, and the description thereof is omitted.

Although the above embodiment has been described using a thin lens model, as shown in FIG. 18, the above-described interval setting method is applied even when a floating tracking type optical system composed of a thick lens is used. By doing so, the same operation and effect as the above embodiment can be realized.

FIG. 18 (a) shows the first example as an example.
Or floating tracking optical system is shown having a first to fourth afocal optical system AFC ₁ ～AFC ₄ consisting thick lens L ₁ ~L ₈ eighth.

Incidentally, H _n (n; natural number) indicates the principal point on the object side (incident light side) of each of the thick lenses L _{1 to} L ₈ , and H _n ′
(N: natural number) indicates the image-side (emission light-side) principal point of each of the thick lenses L _{1 to} L ₈ . D _n ′ (n: natural number) indicates the distance between H _n and H _n ′, and _en ′
(N; natural number) indicates the distance between H _n ′ and H _{n + 1,} and each takes a positive value along the direction of the arrow x.
Here, it is assumed that the specifications of the floating following optical system are as shown in Table 6 below.

[0246]

[Table 6]

The power and the angular magnification γ _N of each of the thick lenses L _{1 to} L ₈ of this floating-following optical system are the same as in the above embodiment, but the distance between the principal points is 10 (mm). The value of e ₄ ′ in Table 3 above is set to 4.08 so that the floating tracking type optical system including the thick lenses L _{1 to} L ₈
To 7.4248.

At this time, the displacement of the floating optical axis FL with respect to the fixed optical axis FIX is y _b = 2 (mm), θ _b = 0.02
In the case of (rad), the paraxial tracking result of the floating following optical system is, as shown in FIG. 18B, the incident light beam incident on the _first thick lens L1 which coincides with the fixed optical axis FIX. 76
After passing through the _{second to seventh} thick lenses L _{2 to} L ₇ ,
Injection consisted of thick lens L ₈ and the exit beam 78 that matches the floating optical axis FL.

Thus, even in the case of a thick lens model,
Angular magnification γ _{N of} each afocal optical system AFC _{1 to} AFC ₄
There together to satisfy both the formulas (I-1) and Formula (I-2), by optimizing the 'spacing e _n with H _{n + 1} and' H _n by using the interval setting method, complete Following conditions can be obtained. In such a thick lens model, even when a floating-following optical system composed of six or more afocal optical systems is set, the same operation and effect as described above can be obtained by applying the above-described interval setting method. It is possible to realize. The other operation and effect are the same as those of the above-described embodiment, and the description thereof is omitted.

The structure of the thick lens model described above,
It goes without saying that the function and effect can be applied not only to the above-described embodiment, that is, the fifth embodiment, but also to the lens models of all the other embodiments.

Next, a floating-following optical system according to a sixth embodiment of the present invention will be described with reference to FIG.

As shown in FIG. 19, the floating-following optical system of the present embodiment is composed of four thin lens optical systems arranged along the traveling direction of the incident light beam 80. Is a first thin lens optical system L ₁ belonging to a floating system and a second thin lens optical system L ₂ belonging to a fixed system.
, A third thin lens optical system L ₃ belonging to the floating system, and a fourth thin lens optical system L ₄ belonging to the fixed system.

The specifications of the first to fourth thin lens optical systems L ₁ , L ₂ , L ₃ , L ₄ are shown in Table 7 below.

[0254]

[Table 7]

The first to fourth thin lens optical systems L ₁ , L ₂ , L ₃ , and L ₄ based on the specifications in Table 7 are calculated by the above-described equations (I-3) to (I-5). That is, it is designed to satisfy the perfect following condition.

Next, the operation of this embodiment will be described.

FIG. 19A shows paraxial tracking results when the floating optical axis FL is displaced in parallel with the fixed optical axis FIX in the floating tracking optical system of the present embodiment. 19 (b) and 19 (c) show that the floating optical axis FL is fixed to the fixed optical axis FIX in the floating tracking type optical system of the present embodiment.
The paraxial tracking result in the case of tilt displacement with respect to is shown.

As shown in FIGS. 19A, 19B and 19C, the incident light beam 80 incident on the _first thin lens optical system L1 coincident with the fixed optical axis FIX is the second and the second light beams. After passing through the _third thin-lens optical systems L ₂ and L ₃ , the light is emitted from the fourth thin-lens optical system L ₄ as an outgoing light beam 82 that coincides with the floating optical axis FL.

In the figure, the first and third thin lens optical systems L ₁ and L ₃ are respectively arranged in parallel with the y-axis, but actually, the first and third thin lens optical systems L ₁ and L ₃ are arranged in parallel. Since the optical systems L ₁ and L ₃ are arranged perpendicular to the floating optical axis FL, they are inclined with respect to the y-axis.

Also, as defined in FIG. 3, the height between the fixed optical axis FIX and the intersection of the floating optical axis FL intersecting the _first thin lens optical system L ₁ is represented by y _b , and the floating optical axis FL If the angle between the fixed optical axis FIX and the fixed optical axis FIX is defined as θ _b , the floating light with respect to the fixed optical axis FIX in the floating tracking type optical system shown in FIGS. 19 (a), 19 (b) and 19 (c) will be described. Axis FL
Are as follows.

In the embodiment shown in FIG. 19A, the displacement of the floating optical axis FL with respect to the fixed optical axis FIX is y _b = 1.
(Mm), θ _b = 0 (rad).

In the embodiment shown in FIG. 19B, the displacement of the floating optical axis FL with respect to the fixed optical axis FIX is:
y _b = 0 (mm) and θ _b = 0.005 (rad).

In the embodiment of FIG. 19C, the displacement of the floating optical axis FL with respect to the fixed optical axis FIX is:
y _b = 1 (mm) and θ _b = 0.01 (rad).

In such a state, the emitted light 82
Are emitted completely coincident with the floating optical axis FL. This is nothing but the fact that the floating tracking optical system according to the present embodiment satisfies the above-described equations (I-3) to (I-5), that is, the perfect tracking condition.

In the present embodiment, the above y _b
The value of and theta _b even if a value other than the above, exit ray 82
However, it goes without saying that it completely matches the floating optical axis FL. As described above, according to the present embodiment, a floating tracking optical system that satisfies the perfect tracking condition can be realized. Therefore, even if the floating system moves parallel to the fixed system, the floating system tilts with the parallel movement. However, it is always possible to obtain the emitted light beam 82 having a fixed position and inclination with respect to the floating system.

Further, while the fifth embodiment requires a minimum of eight lens optical systems, the present embodiment differs from the fifth embodiment in that:
It can be constituted by at least four lens optical systems. For this reason, the amount of light loss can be reduced by the small number of lens optical systems, and downsizing of the optical system and reduction of manufacturing cost can be realized.

Although the present embodiment has been described using a thin lens model, in practice, various applications are possible and effective depending on the lens type, lens configuration, lens material, and the like. This is the same as in the first embodiment.

Next, a floating tracking optical system according to a seventh embodiment of the present invention will be described with reference to FIGS.

As shown in FIG. 20A, the floating-following optical system according to this embodiment includes a plane mirror 86 belonging to the floating system 84.
A first afocal optical system AFC ₁ with, and a second afocal optical system AFC ₂ and having a biconcave lens 90 and a biconvex lens 92 belonging to the fixed system 88.

In FIG. 20A, the floating optical axis FL and the fixed optical axis FIX are shown so as to coincide with each other.

In such a configuration, an incident light beam 94 emitted from a light source provided in a fixed system (not shown) is reflected from a plane mirror 86 and then becomes an exit light beam 96 via a biconcave lens 90 and a biconvex lens 92. Be injected.

The first afocal optical system AFC ₁
Has an angular magnification of 0.5 and is manufactured to have a high transmittance in the wavelength range of the incident light beam 94.

The plane mirror 86 is manufactured so as to have a high reflectance in the wavelength range of the incident light beam 94.

Hereinafter, the operation of this embodiment will be described.

The plane mirror 86 applied to the present embodiment is
With respect to the tilt displacement of the floating system 84, an operation equivalent to that of an afocal system having an angular magnification of -1 is achieved.

First, regarding this point, FIG.
This will be described with reference to FIG.

FIG. 21B shows an afocal optical system 98 having an angular magnification of −1. The angle between an incident light beam 100 incident on the afocal optical system 98 and the optical axis 102 is represented by A. _{If AFC} is used, the angle A _AFC ′ between the emitted light beam 104 and the optical axis 102 satisfies the relationship A _AFC ′ = −A _AFC .

On the other hand, as shown in FIG. 21C, assuming that the angle between the incident light beam 108 incident on the plane mirror 106 and the optical axis 110 (the optical axis coincident with the normal to the plane mirror 106) is A _M , angle a _M formed between the beam 112 and the optical axis 110 ', a _M' satisfies = -A _M the relationship.

This means that the plane mirror 106
Means that an action equivalent to that of the afocal optical system 98 having an angular magnification of −1 (see FIG. 21B) is obtained.

[0280] Referring now to FIG. 20 (a), the terms tilt displacement of the floating system 84, the plane mirror 86, the afocal optical system AFC ₁ described in FIGS. 5 and 6, also, a biconcave lens 90 and both convex lens 92, the afocal optical system AFC ₂ described in FIG. 5 and FIG. 6, respectively the corresponding is found.

[0281] In this case, the first
Afocal angular magnification gamma ₁ of the optical system AFC ₁ of "-1"
And the angular magnification γ ₂ of the second afocal optical system AFC ₂ applied to the present embodiment is
It can be considered as "0.5".

This is nothing but the fact that the floating tracking type optical system of the present embodiment satisfies the above-mentioned formula (I-1), that is, the tilt tracking condition.

Next, the case where the floating system 84 is displaced in inclination with respect to the fixed system 88 will be described with reference to FIG.

In FIG. 20B, the floating system 84 is
8 shows a state in which a tilt displacement Θ _b has occurred.

Since the incident light beam 114 coincides with the fixed optical axis FIX, the inclination A of the reflected light 116 from the plane mirror 86 is
₁ ', A _1' satisfies = 2 [Theta] _b the relationship.

[0286] When the reflected light 116 satisfying the above relationship is incident on the second afocal optical system AFC _2, the slope A ₂ of the second afocal optical system exit ray 118 emitted from the AFC ₂ 'is A ₂ ′ = γ ₂ · A ₂ = γ ₂ · A ₁ ′ = 0.5 × 2Θ _b =
関係 Satisfies the relationship _b .

This is nothing but the fact that the floating following optical system of the present embodiment satisfies the tilt following condition.

Next, a case where the floating system 84 is displaced in parallel with respect to the fixed system 88 will be described with reference to FIG. In the description of the figure, the same components as those in FIG. 17B are denoted by the same reference numerals, and description thereof will be omitted.

In FIG. 21A, the floating system 84 is
Translational movement displacement Y _b state are shown for 8.

In this case, the reflected light 116 from the plane mirror 86
H ₁ ′ and the displacement H ₂ ′ of the exit ray 118 are determined by an angle indicated by β in the figure, and H ₁ ′ = Y _b sin (0.5β) sin β ｛cos
(0.5β)｝ ⁻¹ H ₂ ′ = Y _b sin (0.5β) sin β ｛cos
(0.5β)｝ ^-1 γ ₂ ^-1 is satisfied.

Thus, for example, β = 30 °, γ ₂ = 0.
In the case of 5, H ₂ ′ = 0.268Y _b , and in this case,
Height from floating the optical axis FL to exit ray 118 becomes 0.268Y _b -Y _b = -0.732Y _b.

This is nothing but the fact that the floating tracking type optical system of the present embodiment satisfies the parallel movement tracking condition.

As described above, the floating tracking type optical system according to the present embodiment can satisfy the floating tracking condition, so that the same effects as those of the first embodiment can be obtained.

Further, in this embodiment, since one plane mirror 86 is used as an optical element equivalent to the _first afocal optical system AFC ₁ applied to the first embodiment, It is possible to reduce the number of parts, and as a result, it is possible to reduce the size and the manufacturing cost.

Although the present embodiment has been described using a single-lens system as the _second afocal optical system AFC2, in practice, various types of application are made according to the lens type, lens form and lens material. Is possible and effective,
This is the same as in the first embodiment.

[0296] Further, in this embodiment, as the second afocal optical system AFC _2, for example, the second and the afocal optical system AFC ₂ shown in FIG. 11, the afocal optical shown in FIG. 12 It is also preferable to use the system AFC or the _second afocal optical system AFC2 shown in FIG.

In particular, the second afocal optical system AFC _{2 of} FIG. 11 or the _second afocal optical system AFC of FIG.
_{When 2} is applied to the present embodiment, since the optical system is constituted only by the reflective optical element, the same effect as that of the second embodiment, that is, the elimination of chromatic aberration and the use in the ultraviolet to X-ray region can be achieved. There is an advantage that it becomes possible.

Next, a floating-following optical system according to an eighth embodiment of the present invention will be described with reference to FIG.

As shown in FIG. 22, the floating-following optical system according to the present embodiment includes first to fourth hologram elements 122 and 12 arranged along the traveling direction of the incident light beam 120.
4, 126, 128, and a pinhole plate 130 disposed on the emission side of the fourth hologram element 128. Specifically, the first and second hologram elements 122, 124 and the pinhole The plate 130 is a floating system 1
32, and the third and fourth hologram elements 126 and 128 belong to the fixed system 134.

FIG. 22 shows the floating optical axis FL and the fixed optical axis FIX so as to match each other.

In such a configuration, incident light 120 emitted from a light source provided in a fixed system (not shown)
To the fourth hologram elements 122, 124, 126,
After being sequentially diffracted at 128, the light is emitted as an emitted light beam 136 from the pinhole 130 a of the pinhole plate 130.

In this case, the first to fourth hologram elements 122, 124, 126, and 128 are calculated by the above-described formula (I)
-3) to (I-5), that is, it is designed to satisfy the perfect tracking condition, and is manufactured so as to have a high diffraction efficiency with respect to the wavelength range of the incident light beam 120.

The pinhole plate 130 is positioned so that the pinhole 130a is aligned with the condensing position of the emitted light beam 136.

The operation of the present embodiment will be described below.

In the floating tracking type optical system according to the present embodiment, the first to fourth hologram elements 122, 124,
Of the diffracted light diffracted from 126 and 128, the zero-order light, which is undiffracted light, is unnecessary light and needs to be removed.

Therefore, in the present embodiment, a pinhole plate 130 is provided on the emission side of the fourth hologram element 128.

According to such a configuration, the zero-order light 138 generated from the first hologram element 122, the zero-order light 140 generated from the second hologram element 124, and the zero-order light generated from the third hologram element 126 Most of the light 142 and the zero-order light 144 generated from the fourth hologram element 128 are cut by the pinhole plate 130, and the first-order (or required order) diffracted light passes through the pinhole 130a. As a result, the exit light beam 136 is a light beam formed by the diffracted light of the required order.

As described above, according to the present embodiment, it is possible to realize a floating tracking type optical system satisfying the perfect tracking condition, so that it is possible to obtain the same effect as that of the sixth embodiment. Become.

Further, the floating-following optical system according to the present embodiment comprises the first to fourth hologram elements 122, 124,
Because of the configuration using 126 and 128, extremely good imaging characteristics can be obtained for narrow-band wavelength light such as laser light and bright line spectrum light, and by using a plastics molding technique. At the time of mass production, it can be manufactured at extremely low cost.

As the first to fourth hologram elements 122, 124, 126 and 128, a hologram pattern is formed on, for example, a silver salt photosensitive material or a photosensitive plastic instead of using a plastic molded product. It is also possible to use the hologram element described above.

In this embodiment, a transmission hologram is used, but a reflection hologram can be used in the same manner.

Further, the floating follow-up type optical system of the present embodiment can be configured by combining a general optical element such as a lens mirror and a hologram element.

Next, a floating-following optical system according to a ninth embodiment of the present invention will be described with reference to FIG.

As shown in FIG. 23, the floating-following optical system according to the present embodiment comprises a first afocal optical system AFC ₁ belonging to the floating system 146 and a second afocal optical system AFC belonging to the fixed system 148. ₂ and a stop 158.

The first afocal optical system AFC ₁ is composed of first and second hologram elements 150 and 152, and the second afocal optical system AFC
Reference numeral ₂ includes third and fourth hologram elements 154 and 156.

The stop 158 is disposed on the emission side of the fourth hologram element 156, and has an aperture 15 having a predetermined diameter.
8a are formed.

In FIG. 23, the floating optical axis FL and the fixed optical axis FIX are shown so as to coincide with each other.

In such a configuration, an incident light beam 160 emitted from a light source provided in a fixed system (not shown) is applied to first to fourth hologram elements 150, 152, and 15.
After being sequentially diffracted at 4,156, the aperture 15
The light 8a is emitted as an emission light beam 162.

In this case, the first to fourth hologram elements 150, 152, 154, and 156 constituting the first and second afocal optical systems AFC ₁ and AFC ₂ are calculated by using the above-mentioned formula (I-1) or It is designed so as to satisfy (I-2) and is manufactured so as to have high diffraction efficiency in the wavelength range of the incident light beam 160.

In the present embodiment, the fourth hologram element 156 is provided with an optical property such that the emission light beam 162 is emitted upward in the figure, and one spherical lens and one It is configured to have both functions of the prism.

[0321] The operation of the present embodiment will be described below.

First and second afocal optical systems AFC
₁ , when AFC ₂ satisfies the above equation (I-1), the floating tracking optical system of the present embodiment satisfies the tilt tracking condition.

First and second afocal optical systems AFC
₁ , when AFC ₂ satisfies the above expression (I-2), the floating tracking optical system of the present embodiment satisfies the parallel movement tracking condition.

In such a configuration, the zero-order light 164, which is the undiffracted light generated from the first and third hologram elements 150 and 154, and the zero-order light, which is the undiffracted light generated from the fourth hologram element 156, The light 166 is separated and emitted in a different direction from the emission light beam 162 emitted from the fourth hologram element 156.

The zero-order light 168, which is the non-diffracted light generated from the second hologram element 152, is shielded by the stop 158 to prevent the exit light beam 162 from entering the optical path.

When the floating tracking type optical system of the present embodiment satisfies the tilt tracking condition, the floating system 146 becomes the fixed system 1
It is possible to always obtain an outgoing ray 162 that is inclined with respect to 48 and has the same inclination as this inclination.

When the floating following optical system of this embodiment satisfies the parallel movement following condition, the floating system 14
Even if 6 is translated with respect to the fixed system 148, it is possible to always obtain the emitted light beam 162 that translates in the same manner as this translation.

Further, in the present embodiment, the first to fourth
Since the hologram elements 150, 152, 154, and 156 are used, the same effects as those of the eighth embodiment can be obtained.

Even when the floating tracking type optical system according to the present embodiment is constituted by, for example, four or more afocal optical systems as shown in the fifth embodiment, the perfect tracking condition is not satisfied. Needless to say.

Next, a floating tracking optical system according to a tenth embodiment of the present invention will be described with reference to FIG.

As shown in FIG. 24A, the floating-following optical system according to the present embodiment comprises first and second floating-following optical systems 170 and 17 arranged along the traveling direction of an incident light beam.
2 and a first floating-following optical system 1
70 includes first to fourth afocal systems 174, 1
76, 178, and 180 are provided, and the fifth floating-following optical system 172 is provided with fifth to eighth afocal systems 182, 184, 186, and 188.

Specifically, the first, third, sixth, and eighth afocal systems 174, 178, 184, 188 belong to the first floating system 190, and the fifth and seventh afocal systems Afocal system 182, 186 of the second floating system 192
And the second and fourth afocal systems 1
76 and 180 belong to the fixed system 194.

In FIG. 24A, the fixed optical axis FI
X, the first floating optical axis FL ₁ and the second floating optical axis FL ₂ are shown so as to match each other.

In such a configuration, an incident light beam 196 that is incident on the fixed optical axis FIX from a light source provided in a fixed system (not shown) is transmitted to the first floating-following optical system 170.
The light beam 198 passes through the second floating-following optical system 172 and exits as a light beam 200.

[0335] In this case, incident light 196, light 198 and exit ray 200 is fixed optical axis FIX, coincides with the first floating the optical axis FL ₁ and the second floating optical axis FL _2.

The first and second floating-following optical systems 1
70 and 172 correspond to the formulas (I-1) and (I-
It is designed so as to satisfy the condition 2) and also to satisfy the perfect following condition similarly to the fifth embodiment.

Hereinafter, the operation of this embodiment will be described.

In the floating-following optical system according to the present embodiment, as shown in FIG. 24B, between the fixed system 194 and the first floating system 190, and between the first floating system 190 and the second floating system 190.
Consider a case where a tilt displacement or a translation displacement occurs between the floating system 192 and the floating system 192.

The first and second floating-following optical systems 170,
Reference numeral 172 denotes a fixed optical axis FI to satisfy the perfect following condition.
The incident light beam 196 along X is the first floating-following optical system 1
70, the first floating-following optical system 170
The light beam 198 emitted from the optical system enters the second floating-following optical system 172 in a state where it coincides with the _first floating optical axis FL1. Then, the emitted light beam 200 emitted from the second floating-following optical system 172 is emitted in a state of being coincident with the _second floating optical axis FL2.

As described above, according to the present embodiment, the first and second floating tracking optical systems 17 satisfying the perfect tracking condition.
Since the three systems (ie, the fixed system 194 and the first and second floating systems 190 and 192) are optically connected by 0 and 172, even if these three systems are relatively displaced,
The three systems can be optically connected without causing optical axis shift.

In this embodiment, two sets of floating-following optical systems are used. However, as needed, an arbitrary number of systems can be used optically by using an arbitrary number of floating-following optical systems. It is also possible to configure to connect. That is, if K sets of floating follow-up optical systems are used, it is possible to optically connect up to [K + 1] relatively displaceable systems.

The floating follow-up type optical system to be used is not limited to the one that satisfies the perfect follow-up condition. Can also be used.

Also, the second and third afocal systems are used.
The reflecting mirror shown in the sixth embodiment or the floating-following optical system constructed without using the afocal system shown in the sixth embodiment can be applied.

Further, various applications are possible and effective for the lens type, lens form, and lens material used as the optical system, as in the first embodiment. Next, a floating tracking optical system according to an eleventh embodiment of the present invention will be described with reference to FIG.

FIG. 25 shows the configuration of a laser scanning microscope to which the floating tracking type optical system 240 of this embodiment is applied.

As shown in FIG. 25, the laser scanning microscope applied to the present embodiment has a fixed system 20 having a water-cooled laser oscillator 204 fixed on a fixed base 202.
6 and a floating system 212 having an optical microscope main body 210 mounted on an anti-vibration table 208. The floating-following optical system 240 according to the present embodiment It is arranged between the fixed system 206 and the floating system 212 so as to be connected to each other.

A power supply 214 is connected to the water-cooled laser oscillator 204 belonging to the fixed system 206, and the power supply 214 supplies power to the water-cooled laser oscillator 204. Further, a heat exchanger 220 is connected to the water-cooled laser oscillator 204 via two pipes 216 and 218 so that cooling water (not shown) circulates through the water-cooled laser oscillator 204. Have been.

The optical microscope body 21 belonging to the floating system 212
A sample stage 222 on which a predetermined sample (not shown) can be placed, and a lens barrel 224 capable of observing the sample on the sample stage 222 are provided at 0. The optical microscope body 21
A laser scanning unit 226 including a photodetector and an optical scanner (both not shown) is connected to the optical scanning unit 0. The optical microscope main body 210 and the laser scanning unit 226 are optically connected by a relay lens 228. ing.

The floating system 212 has degrees of freedom in the θz, θx, and θy directions around the coordinate axes (x, y, z) in the drawing.

The floating follow-up type optical system 2 of the present embodiment
Reference numeral 40 denotes a first to fourth afocal systems 232 and 232 arranged along the traveling direction of the laser light 230 so as to guide the laser light 230 oscillated from the water-cooled laser oscillator 204 toward the floating system 212. 234,23
6,238, specifically, the first
And the third afocal system 232, 236 is a floating system 2
12, and the second and fourth afocal systems 234 and 238 are
Is fixed to a fixed base 202 belonging to

In this case, the floating tracking type optical system 240 satisfies the above-mentioned equations (I-1) and (I-2), and also satisfies the perfect tracking condition as in the fifth embodiment. Designed to be. The water-cooled laser oscillator 204 is, for example, a multi-line argon ion laser including an ultraviolet region.
Has an ultraviolet region having a wavelength of 351 to 364 nm, a blue line of 488 nm, and a green line of 514.5 nm. Therefore, the floating tracking optical system 240 of the present embodiment is sufficiently corrected for aberrations in these wavelength ranges.

The operation of the present embodiment will be described below.

The laser beam 230 oscillated from the water-cooled laser oscillator 204 passes through the pair of plane mirrors 242 and 244 attached to the fixed base 202 and the floating following optical system 2.
It is incident on 40.

At this time, the laser light 230 that has passed through the floating follow-up type optical system 240 is reflected from a plane mirror 246 attached to the vibration isolation table 208, and then transmitted through the afocal system 248 on the vibration isolation table 208. Scan unit 2
26. The laser beam 230 that has passed through the afocal system 248 is calibrated to a beam diameter that matches the optical system of the optical microscope main body 210.

The laser light 230 incident on the laser scan unit 226 is guided to the optical microscope main body 210 via the relay lens 228, and is then applied to the sample on the sample stage 222.

At this time, the reflected light or fluorescent light from the sample is
After reversing the illumination light path, the laser scan unit 22
6 and is output as an image signal.

In this case, in the present embodiment, the fixed system 206 and the floating system 212 are optically connected by the floating tracking optical system 240 that satisfies the perfect tracking condition. Even when the laser beam 230 is displaced with respect to the table 202, the position and direction in which the laser light 230 enters the laser scan unit 226 are always kept constant. As a result, the optical performance of the laser scanning microscope is not affected at all.

According to the present embodiment, the water-cooled laser oscillator 204 and the optical microscope main body 210 are separately and independently arranged, and the optical microscope main body 210 is
Since it is mounted on the vibration isolation table 208 belonging to the floating system 212, two pipes 216, 2
The vibration of the cooling water generated from the water-cooled laser oscillator 204 via 18 is not transmitted to the optical microscope main body 210. Therefore, even when an experiment using micromanipulation, for example, which extremely dislikes vibration, is performed, there is no influence from the vibration.

In the present embodiment, a multi-line argon ion laser including an ultraviolet region is applied as the water-cooled laser oscillator 204. However, the present invention is not limited to this. For example, a laser including an infrared region as a wavelength region may be used. Or
Single-line laser, gas laser (helium-neon laser, krypton-argon laser) as an oscillation type, various solid-state lasers and dye lasers as lasers other than gas lasers, and air-cooled lasers as cooling methods for these lasers It is possible to

Further, the water-cooled laser oscillator 204 and the optical microscope main body 210 applied to the present embodiment are installed on separate vibration isolation tables, respectively, and these are optically controlled by the floating tracking type optical system 240. You may connect. In this case, vibration transmitted from the water-cooled laser oscillator 204 to the optical microscope main body 210 can be completely cut off.

Further, the floating tracking type optical system used in the present embodiment is not limited to an optical system satisfying the perfect tracking condition, but an optical system satisfying the parallel movement tracking condition according to the required function. It is also possible to apply a system or an optical system that satisfies the tilt following condition. When using an optical system that satisfies the tilt follow-up condition, the illumination performance of the microscope is not degraded by the displacement of the optical axis in the parallel movement direction.
It is preferable to use a laser light source having a beam diameter large enough to cover the range of deviation.

Also, as the floating follow-up type optical system used in the present embodiment, an optical system constituted by a reflection optical system applied to the second and third embodiments, and an optical system applied to the sixth embodiment. It is also possible to apply an optical system that does not use the afocal system described above.

Further, as for the optical system applied to the present embodiment, various applications are possible and effective according to the lens type, lens form and lens material. The same is true.

The afocal system 248 applied to the present embodiment is mounted on a fixed base 202 between the water-cooled laser oscillator 204 and the floating tracing optical system 240, or floating with the water-cooled laser oscillator 204. Tracking optical system 2
40 and between the floating tracking optical system 240 and the laser scan unit 226. The afocal system 248 is not always necessary.

Next, a floating tracking optical system according to a twelfth embodiment of the present invention will be described with reference to FIG.

FIG. 26 shows the configuration of a reduced projection type semiconductor exposure apparatus to which the floating tracking type optical system 278 of the present embodiment is applied.

As shown in FIG. 26, a reduced projection type semiconductor exposure apparatus applied to the present embodiment is
0 is fixed, and a floating system 262 to which a semiconductor exposure apparatus main body 260 that pattern-illuminates the wafer 258 on the xyzθ stage 256 with the illumination light 254 emitted from the illumination light source device 250 is attached. Therefore, the floating following optical system 278 of the present embodiment
The fixed system 252 and the floating system 262 are connected so that the illumination light source device 250 and the semiconductor exposure apparatus main body 260 are optically connected.
And is located between.

[0368] The floating system 262 is provided with the spring 2 on the fixed system 252.
64, a semiconductor exposure apparatus main body 260 and an xyzθ stage 256.
Are mounted on a vibration isolation table 266.

[0369] Such a floating system 262 has degrees of freedom in the θz, θx, and θy directions around the coordinate axes (x, y, z) in the figure.

The floating follow-up type optical system 2 of the present embodiment
78 is an illumination light source device 250 and a semiconductor exposure apparatus main body 2
A first to fourth afocal system arranged along the traveling direction of the illumination light 254 emitted from the illumination light source device 250 so as to optically connect with the compound eye lens 268 provided at the entrance of the light source device 250. 270,272,274,276
Specifically, the first and third afocal systems 270 and 274 are fixed to the vibration isolation table 266 belonging to the floating system 262, and the second and fourth afocal systems 272 are provided. , 276 are fixed to a fixing system 252.

As the illumination light source device 250 applied to the present embodiment, for example, an excimer laser is used.

In this embodiment, for example, the illumination light source device 250 and the floating tracking type optical system 278 are adjusted so that the light beam diameter of the illumination light from the illumination light source device 250 matches the optical system of the semiconductor exposure apparatus main body 260. An afocal system fixed to the illumination light source device 250 is provided between them, or for example, a floating-following optical system 278 and a compound eye lens 268
It is preferable to provide an afocal system fixed to the vibration isolation table 266 between the two. Further, it is preferable to provide both of the two afocal systems.

In this case, the floating tracking type optical system 278 satisfies the above-described equations (I-1) and (I-2), and also satisfies the perfect tracking condition as in the fifth embodiment. Designed to be.

The operation of the present embodiment will be described below.

The illumination light 254 transmitted from the illumination light source device 250 via the floating follow-up type optical system 278 is taken into the semiconductor exposure apparatus main body 260 by the compound eye lens 268, and then the three mirrors 280, 282 , 284 to the condenser lens 286.

The illumination light 254 transmitted to the condenser lens 286 is applied from the mask 288 to the wafer 258 on the xyzθ stage 256 via the projection lens 290. At this time, the pattern of the mask 288 is reduced and projected on the wafer 258.

In this case, in the present embodiment, since the illumination light source device 250 and the semiconductor exposure apparatus main body 260 are optically connected by the floating tracking type optical system 278 satisfying the perfect tracking condition, vibration isolation is performed. Stand 266 is fixed system 25
2, the position and direction of the illumination light 254 incident on the compound eye lens 268 are always kept constant even when the semiconductor exposure apparatus main body 260 is displaced by displacement.
Specifically, even when the semiconductor exposure apparatus main body 260 is displaced due to the movement of the center of gravity accompanying the operation of the xyzθ stage 256, the position and direction in which the illumination light 254 enters the compound eye lens 268 are always kept constant. Therefore, it is possible to prevent the occurrence of uneven illumination on the wafer 258, and
The illumination light 254 can be efficiently irradiated onto the wafer 258.

According to the present embodiment, illumination light source device 250 and semiconductor exposure apparatus main body 260 are separately and independently arranged, and semiconductor exposure apparatus main body 260 is provided.
Is mounted on the anti-vibration table 266 belonging to the floating system 262, so that vibrations generated from the illumination light source device 250 and other vibrations transmitted from the outside to the fixed system 252 are transmitted to the semiconductor exposure apparatus main body 260. There is no. Therefore,
The mechanical positioning accuracy of the xyzθ stage 256 and the positional accuracy of reducing and projecting the pattern of the mask 288 onto the wafer 258 are not impaired by external vibration.

In the present embodiment, an excimer laser is used as the illumination light source device. However, the present invention is not limited to this. For example, the same effect can be obtained by using synchrotron radiation (SOR). In this case, it is possible to obtain illumination light in the X-ray range from the ultraviolet range.

Alternatively, the semiconductor exposure apparatus main body 260 and the illumination light source device 250 may be installed on separate anti-vibration tables, respectively, and these may be optically connected by the floating tracking type optical system 278. In this case, vibration transmitted from the illumination light source device 250 to the semiconductor exposure apparatus main body 260 can be completely cut off.

Also, the floating tracking type optical system used in the present embodiment is not limited to an optical system satisfying the perfect tracking condition. For example, the floating tracking type optical system satisfying the parallel movement tracking condition according to the required function. It is also possible to use an optical system that satisfies the tilt following conditions. When an optical system that satisfies the tilt following condition is used, the beam on the light source side
It is similar to the eleventh embodiment in that it is desirable to increase the diameter of the drum.

Also, as the floating-following type optical system used in the present embodiment, an optical system constituted by the reflecting optical system applied to the second and third embodiments, and the floating following optical system applied to the sixth embodiment. It is also possible to apply an optical system that does not use the afocal system described above.

Further, the optical system applied to the present embodiment is variously applicable and effective according to the lens type, lens form, and lens material, as described in the first embodiment. The same is true.

Next, a floating tracking optical system according to a thirteenth embodiment of the present invention will be described with reference to FIG.

FIG. 27 shows the configuration of a 1: 1 projection type semiconductor exposure apparatus to which the floating tracking type optical system 320 of the present embodiment is applied.

As shown in FIG. 27, the 1: 1 projection type semiconductor exposure apparatus applied to the present embodiment includes a fixed system 292 in which an unillustrated illumination light source device is disposed, and illumination light emitted from the illumination light source device. 294 to the wafer stage 296
A floating system 302 equipped with a semiconductor exposure apparatus main body 300 for pattern-illuminating the upper wafer 298 is provided. The floating follow-up optical system 320 of the present embodiment includes an illumination light source device (not shown) and a semiconductor exposure apparatus. It is arranged between the fixed system 292 and the floating system 302 so as to be optically connected to the main body 300. For the illumination light source device, for example, synchrotron radiation (SOR) or the like is used.

[0387] The floating system 302 is provided with a spring 3 on the fixed system 292.
The semiconductor exposure apparatus main body 300 is mounted on the anti-vibration table 306.

The floating system 302 has degrees of freedom in the θz, θx, and θy directions around the coordinate axes (x, y, z) in the drawing.

The floating follow-up type optical system 3 of the present embodiment
Reference numeral 20 denotes first and second afocal systems 308 and 310 arranged along the traveling direction of the illumination light 294 so as to optically connect an illumination light source device (not shown) and the semiconductor exposure apparatus main body 300. The first afocal system 308 belongs to the floating system 302, and the second afocal system 310 belongs to the fixed system 292.

The first afocal system 308 has the illumination light 2
A first concave mirror 312 having an opening 312a through which the light passes through 94, and the illumination light 294 passing through the opening 312a of the first concave mirror 312 is reflected in the direction of the first concave mirror 312 and is reflected from the first concave mirror 312. And a second concave mirror 314 having an opening 314a through which the transmitted light passes. Then, the first and second concave mirrors 312,
314 is fixed to the vibration isolation table 306 belonging to the floating system 302.

The second afocal system 310 includes a third concave mirror 316 having an opening 316a through which light passing through the opening 314a of the second concave mirror 314 is formed, and an opening 316a of the third concave mirror 316. And a convex mirror 318 that reflects the transmitted light toward the third concave mirror 316. Then, the third concave mirror 316 and the convex mirror 318
Are fixed to a fixing system 292.

In this case, the floating tracking type optical system 320 is designed so as to satisfy the above-mentioned formula (I-1), that is, the tilt tracking condition.

The operation of the present embodiment will be described below.

When illumination light emitted from an illumination light source device (not shown) is applied to the first afocal system 308, the first
Of the illumination light irradiating the concave mirror 312 of the first concave mirror 312 from the opening 312a of the first concave mirror 312,
After being reflected from the reflecting surface 314b of the second concave mirror 314,
The light is emitted to the reflection surface 312b of the first concave mirror 312. At this time, the light reflected from the reflecting surface 312b of the first concave mirror 312 passes through the opening 314a of the second concave mirror 314, and is emitted toward the second afocal system 310.

The light that has passed through the opening 314a of the second concave mirror 314 and emitted to the second afocal system 310 passes through the opening 316a of the third concave mirror 316, and then irradiates the reflection surface 318a of the convex mirror 318. Is done.

The light applied to the reflecting surface 318a of the convex mirror 318 is reflected from the reflecting surface 318a and then reflected from the reflecting surface 316b of the third concave mirror 316 to become the outgoing light 322, and the second light is emitted. Afocal 31
Fired from 0.

The emitted light 322 emitted from the second afocal system 310 is subsequently transmitted to the semiconductor exposure apparatus main body 300 mounted on the vibration isolation table 306.

The emission light 322 transmitted to the semiconductor exposure apparatus main body 300 passes through an opening 3 formed in a mask stage 324 whose position is controlled in the coordinate axis (y, z) direction in the figure.
After passing through the opening 324a, the wafer 298 on the wafer stage 296 is irradiated through a mask 326 provided on the exit side of the opening 324a. The wafer stage 296
Is moved by the wafer stage holding member 328.
6 and is position-controlled in the direction of the coordinate axes (y, z) in the figure.

In this case, the mask 3
The pattern formed on 26 is projected at the same magnification.

As described above, in the present embodiment, the illumination light source device (not shown) and the semiconductor exposure apparatus main body 300 are
Since the optical system is optically connected by the floating tracking optical system 320 that satisfies the tilt tracking condition, even if the vibration isolation table 306 is displaced with respect to the fixed system 292 and the semiconductor exposure apparatus main body 300 is displaced, the emitted light is The direction in which the 322 enters the mask 326 and the wafer 298 is always kept constant. Specifically, even when the semiconductor exposure apparatus main body 300 is displaced by the movement of the center of gravity accompanying the operation of the mask stage 324 or the wafer stage 296, the emission light 322
The direction in which the light is incident on the mask 326 and the wafer 298 is always kept constant, so that a fine mask pattern on the order of submicrons can be projected onto the wafer 298 at exactly the same magnification.

According to the present embodiment, since semiconductor exposure apparatus main body 300 is mounted on floating system 302, vibration transmitted from the outside to fixed system 292 is transmitted to semiconductor exposure apparatus main body 300. It will not be done. Therefore, the mechanical positioning accuracy of the mask stage 324 and the wafer stage 296, that is, the position accuracy of projecting the pattern of the mask 326 on the wafer 298 at the same magnification is not impaired by external vibration.

In this embodiment, synchrotron radiation (SOR) is used as the illumination light source device. However, the present invention is not limited to this. For example, an excimer laser can provide the same effects as described above.

When the illumination light source device is a vibration source, the semiconductor exposure apparatus main body 300 and the illumination light source device are installed on separate vibration isolation tables, respectively, and these are optically controlled by the floating following optical system 320. May be connected. In this case, vibration transmitted from the illumination light source device to the semiconductor exposure apparatus main body 300 can be completely cut off.

The floating follow-up type optical system used in the present embodiment is not limited to an optical system satisfying the tilt condition, but an optical system satisfying the parallel movement follow-up condition according to the required function. Alternatively, it is also possible to use an optical system that satisfies the perfect tracking condition.

When the wavelength range of the illumination light used is X-rays, the floating-following optical system used in the present embodiment should be constituted only by a reflection optical system as in the present embodiment. Is effective, but when using illumination light having a wavelength range equal to or greater than the near ultraviolet range, it is preferable to use the lens optical system described in the first and fifth embodiments. Further, as the floating following optical system used in the present embodiment,
The floating follow-up type optical system not using the afocal system shown in the sixth embodiment is also applicable.

[0406] The optical system applied to the present embodiment can be applied to various types and effective according to the lens type, lens form, and lens material. The same is true.

Next, a floating tracking type optical system according to a fourteenth embodiment of the present invention will be described with reference to FIG.

FIG. 28 shows the configuration of a laser length measuring apparatus to which the floating tracking type optical system 358 of this embodiment is applied.

[0409] The laser length measuring apparatus applied to the present embodiment measures the displacement of the object to be measured on the vibration isolation table 348 by the laser length measuring device 330 arranged independently of the floating system 340. It is configured to be.

As shown in FIG. 28, a laser length measuring apparatus applied to the present embodiment comprises a fixed length system 334 in which a laser length measuring head 330 incorporating a Zeeman laser oscillator (not shown) and a vacuum chamber 332 are arranged. The laser measuring head 3 is provided in the vacuum chamber 332.
And a floating system 340 equipped with an interference optical system 338 for generating a predetermined interference light 362 by the laser light 336 emitted from the laser beam 336. It is arranged between the laser length measuring head 330 and the interference optical system 338 so as to optically connect the laser beam and the interference optical system 338.

[0411] The laser measuring head 330 is
2 on a fixing system 334. Further, the vacuum chamber 332 is fixed on a fixing system 334, and a laser beam 336 from the laser length measuring head 330.
And a glass window 344 capable of transmitting the interference light 362 from the interference optical system 338.

[0412] The floating system 340 includes a spring 3 on the fixed system 334.
An anti-vibration table 348 is provided, which is supported via 46, and the interference optical system 338 is mounted on the anti-vibration table 348.

[0413] Such a floating system 340 has degrees of freedom in the θz, θx, and θy directions around the coordinate axes (x, y, z) in the drawing.

The floating follow-up type optical system 3 of the present embodiment
58 is a laser measuring head 330 and an interference optical system 338
The optical system includes an afocal system 350 fixed on a fixed system 334 and a plane mirror 352 mounted on an anti-vibration table 348 so that the afocal system 35 is optically connected.
0 is provided with a concave mirror 354 and a biconvex lens 356 opposed to each other.

According to such a floating tracking type optical system 358, the laser beam 336 emitted from the laser measuring head 330 passes through the glass window 344 and passes through the vacuum chamber 3
After being incident on the inside 32, the light is reflected from the plane mirror 352, passes through the glass window 344 again, and is emitted outside the vacuum chamber 332.

[0416] The laser beam 336 emitted to the outside of the vacuum chamber 332 is reflected by the concave mirror 354 and then transmitted through the glass window 344 again by the biconvex lens 356 and transmitted into the vacuum chamber 332.

[0417] The laser beam 336 transmitted into the vacuum chamber 332 becomes an incident light beam 360 and thereafter enters the interference optical system 338 on the vibration isolation table 348.

The incident light ray 36 incident on the interference optical system 338
After being converted into a predetermined interference light 362 by the interference optical system 338, 0 is transmitted through the glass window 344 and emitted outside the vacuum chamber 332.

[0419] Interference light 3 emitted outside vacuum chamber 332
62 is a concave mirror 354 after transmitting through the biconvex lens 356.
Through the glass window 344 and the vacuum chamber 33
2 is transmitted.

The interference light 362 transmitted into the vacuum chamber 332 is emitted from the plane mirror 352 through the glass window 344 to the outside of the vacuum chamber 332, and becomes an emission light beam 364, which is incident on the laser length measuring head 330. I do.

Then, the displacement of the object to be measured is measured by detecting the optical characteristics of the emitted light beam 364 by the laser length measuring head 330.

Note that such a floating tracking type optical system 358
In, the laser light 336 and the interference light 362 transmitted between the concave mirror 354 and the plane mirror 352 are configured to pass through a notch 356 a formed in the biconvex lens 356.

Also, the vibration isolation table 348 belonging to the floating system 340
The upper interference optical system 338 transmits a polarized beam splitter 366 that splits the incident light beam 360 into two and a first corner cube prism 368 that reflects the reflected light reflected from the polarized beam splitter 366 to the polarized beam splitter 366 again. And a second corner cube prism 372 that reflects the transmitted light transmitted through the polarizing beam splitter 366 to the polarizing beam splitter 366 again.

[0424] The interferometer 370 is fixed on the vibration isolation table 348, and the second corner cube prism 37
2 is mounted on an X stage 374 mounted on a vibration isolation table 248.

In this case, the afocal system 350 constituting the floating tracking type optical system 358 has an angular magnification of 0.5.
And is designed to satisfy the tilt following condition.

Hereinafter, the operation of this embodiment will be described.

The laser beam 336 emitted from the laser length measuring head 330 passes through the floating follow-up optical system 358, becomes an incident ray 360, and enters the polarization beam splitter 366.

The light reflected from the polarizing beam splitter 366 is applied to the first corner cube prism 368.
After that, the light becomes reference light 376 and reenters the polarization beam splitter 366.

On the other hand, the transmitted light transmitted through the polarizing beam splitter 366 is transmitted to the second corner cube prism 372
, The light becomes object light 378 and enters the polarization beam splitter 366 again.

At this time, the interference light 362 generated by the interference between the reference light 376 and the object light 378 passes through the floating follow-up optical system 358, becomes an emission light 364, and is transmitted to the laser length measuring head 330. Incident.

The displacement of the object to be measured, that is, the X stage 374 is measured by detecting the optical characteristics of the emitted light beam 364 by the laser length measuring head 330.

As described above, in this embodiment, the laser measuring head 330 and the interference optical system 338 are optically connected by the floating following optical system 358 that satisfies the tilt following condition. Even when the 348 is displaced with respect to the fixed system 334, the direction in which the incident light ray 360 enters the interferometer 370 is always kept constant, and the outgoing light ray 364 is kept constant by the laser length measuring head 330
Is always kept constant.

According to the present embodiment, the floating system 34
By isolating the entire structure on the vacuum chamber 332 in the vacuum chamber 332, the vibration isolation table 3 is not affected by the atmospheric pressure.
It becomes possible to measure the displacement of the X stage 374 installed on the top 48 with extremely high accuracy.

The structure of the present embodiment is particularly effective when applied to a so-called scanning probe microscope such as a scanning tunnel microscope or a scanning atomic force microscope. Because, in a scanning probe microscope, the probe and the sample to be measured are placed in a vacuum and the position of the sample table is measured with a laser length measuring device in order to observe and measure the fine surface shape at the atomic level with high accuracy. This is because there are cases where

More specifically, the entire configuration of the present embodiment is set on a large anti-vibration table, the X stage 374 is used as a sample table, and a probe and related mechanisms are mounted on the anti-vibration table 348. By installing, a scanning probe microscope capable of observing and measuring a measurement sample on the X stage 374 with high accuracy can be realized.

In this embodiment, a Zeeman laser oscillator is built in the laser length measuring head 330.
The invention is not limited to this. For example, a gas laser oscillator, a semiconductor laser oscillator, or the like may be incorporated. Also, the first and second corner cube prisms 368,
As 372, for example, a cat's eye may be used.
Although the single-pass system is applied to the interference optical system 338 applied to the present embodiment, a double-pass system may be applied.

Note that the vacuum chamber 332 is not always necessary. Further, the vacuum chamber 332 and the glass window 3
When there is no 44, as a floating following optical system, for example,
A floating-following optical system as shown in the first to third and fifth to ninth embodiments may be used.

Further, as for the optical system applied to this embodiment, various applications are possible and effective according to the lens type, lens form and lens material. The same is true.

Next, a floating following optical system according to a fifteenth embodiment of the present invention will be described with reference to FIG.

FIG. 29 shows a configuration of a laser scanning microscope to which the floating tracking type optical system 394 of the present embodiment is applied. In the description of the present embodiment, the first
The same components as those of the first embodiment (see FIG. 25) are denoted by the same reference numerals, and description thereof will be omitted.

As shown in FIG. 29, a laser scanning microscope applied to the present embodiment has a laser oscillation unit and an optical microscope main body 210 to which a lens barrel 224 is attached.
, Photodetector and optical scanner (neither shown)
And a laser scanning unit 226 incorporating the laser scanning unit 226. The floating-following optical system 394 of the present embodiment is disposed so as to optically connect the laser oscillation unit and the laser scanning unit 226. The optical microscope main body 210 and the laser scan unit 226 are optically connected by a relay lens 228.

The laser oscillation unit includes a laser oscillator 380, a fixing plate 384 for fixing the laser oscillator 380 on a surface plate 382, and a second afocal system 386 described later. The fixing plate 384 is fastened on the surface plate 382 by screws 388.

[0443] The floating tracking type optical system 394 is provided along the traveling direction of the laser light 390 oscillated from the laser oscillator 380 so as to optically connect the laser oscillation unit and the laser scan unit 226.
Afocal system 392 and the second afocal system 3
86. That is, in the present embodiment, the second afocal system 386 which is the configuration of the laser oscillation unit also has the configuration of the floating tracking optical system 394.

In such a floating tracking type optical system 394, the first afocal system 392 is fixed on the surface plate 382, and the second afocal system 386 is
It is fixed on a fixing plate 384.

In this case, the floating tracking type optical system 394 is designed so as to satisfy the above-mentioned equation (I-1), that is, the tilt tracking condition.

[0446] The operation of the present embodiment will be described below.

The laser light 390 oscillated from the laser oscillator 380 passes through the floating follow-up type optical system 394, becomes an incident light beam 396, and becomes a laser scan unit 226.
Incident on.

The incident light beam 396 that has entered the laser scan unit 226 is guided to the optical microscope main body 210 via the relay lens 228, and then irradiates a sample on a sample stage (not shown).

At this time, the reflected light or fluorescent light from the sample is
After reversing the incident optical path, the laser scan unit 22
6 and is output as an image signal.

As described above, in the present embodiment, the floating tracking type optical system 394 satisfies the tilt tracking condition, so that the laser oscillation unit (380, 384, 386) is attached to and detached from the laser scanning unit 226. Even when the oscillation direction of 390 changes, the direction in which the incident light beam 396 enters the laser scan unit 226 is always maintained in a constant direction. As a result, the optical performance of the laser scanning microscope is not affected at all.

By the way, a laser oscillator using an argon ion laser is most often used in a scanning laser fluorescence microscope used in the fields of medicine and physiology. The life of this laser oscillator is about 2,000 hours. is there.

The laser oscillator whose life has expired needs to be replaced, and the optical axis adjustment work performed at the time of the replacement work is not only impossible for general users but also for a skilled worker. Needs time. In particular, if the direction adjustment of the laser beam is insufficient, there is a problem that the pixel shift occurs and the confocal effect, which is the most important function in the scanning laser microscope, is impaired.

However, by incorporating the floating tracking type optical system 394 into the laser oscillation units (380, 384, 386) as in the present embodiment, the above disadvantage can be solved. That is, for example, in an assembly and adjustment process in a factory, the first jig is used as an adjustment jig.
The same components as those of the afocal system 392 and the surface plate 382 are prepared. Then, in a state where the laser oscillation unit (380, 384, 386) is incorporated therein, an incident light beam 396 from the second afocal system 386 is provided.
Is fixed to the fixed plate 384 or the laser oscillator 380 or the second afocal system 386
Adjust the position of.

According to such a configuration, the incident light beam having high directional accuracy can be obtained simply by fixing the laser oscillation units (380, 384, 386) at predetermined positions on the surface plate 382 with not so high positioning accuracy. 396 can be secured.

That is, according to the present embodiment, the surface plate 382
Belongs to the fixed system and the laser oscillation unit (38
0, 384, 386) can be regarded as belonging to the floating system, so that the laser oscillation units (380, 384, 38)
Even if the oscillation direction of the laser beam 390 is displaced in the yz plane (that is, the displacement in the θz direction) by the exchange operation of 6), the incident light beam 396 can be displaced by the laser scanning unit
The direction of incidence on 6 is always kept constant.

The floating follow-up type optical system 3 of the present embodiment
94 satisfies the inclination follow-up condition, but does not satisfy the parallel movement follow-up condition. Therefore, of the displacement components of the laser oscillation units (380, 384, 386) in the yz plane, the illumination component of the optical system from the laser scan unit 226 to the optical microscope main body 210 is not degraded by the translation component. The incident beam 3 is larger than the beam diameter required in the laser scan unit 226.
It is preferable to set the beam diameter of 96 large. In this case, in the optical path between the second afocal system 386 and the laser scan unit 226, or in the optical path between the laser oscillator 380 and the first afocal system 392,
Alternatively, it is preferable to add an appropriate afocal system in both optical paths.

The floating follow-up type optical system 3 of this embodiment
As the 94, for example, a floating-following optical system as described in the first to third and fifth to ninth embodiments may be used. In this case, when a floating tracking type optical system that satisfies the perfect tracking condition is used, it is not necessary to set the beam diameter to a relatively large value as described above.

Further, as for the optical system applied to the present embodiment, various applications are possible and effective according to the lens type, lens form and lens material. The same is true.

Next, a floating following optical system according to a sixteenth embodiment of the present invention will be described with reference to FIG.

FIG. 30 shows a configuration of an image blur prevention camera to which the floating tracking type optical system 408 of the present embodiment is applied.

As shown in FIG. 30A, in the image blur prevention camera applied to the present embodiment, a light beam 398 from a subject (not shown) is applied to the image sensor 402 via the imaging lens 400. A floating tracking type optical system 408 is arranged on the incident side of the imaging lens 400 so as to form an image.

The floating-following optical system 408 is constituted by first and second afocal systems 404 and 406 arranged along the traveling direction of the light beam 398. 404 belongs to a floating system 410 integrally formed with a camera body (not shown),
Further, the second afocal system 406 is a fixed system 412 made of an inertial stabilizing member (not shown) such as a gyro.
Belongs to The fixing system 412 is attached to the camera body.

The imaging lens 400 and the imaging device 40
2 belongs to the floating system 410. FIG. 30 (a)
In the figure, the floating optical axis FL and the fixed optical axis FIX are shown as being coincident with each other.

In such a configuration, the fixed optical axis FIX
The light ray 398 from the subject incident on the floating tracking type optical system 408 in parallel along, is emitted from the imaging lens 400, becomes a convergent light ray 414, and forms an image at one point 416 on the image sensor 402.

In this case, the floating tracking type optical system is designed so as to satisfy the above-mentioned formula (I-1), that is, the tilt tracking condition.

Hereinafter, the operation of this embodiment will be described.

FIG. 30B shows a state in which the camera body is tilted and displaced due to, for example, vibration of the automobile or camera shake which occurs when taking a picture while riding on a driving automobile or the like.

[0468] In this case, the first afocal system 404 belonging to the floating system 410 accompanies the tilt displacement of the camera body.
The second afocal system 406 belonging to the fixed system 412,
Is maintained in the initial position by an inertia stabilizing member such as a gyro.

Accordingly, the light ray 398 incident parallel to the fixed optical axis FIX is converted by the floating tracking type optical system 408 into a light ray 418 parallel to the floating optical axis FL.
One point 41 on the image sensor 402 via the imaging lens 400
6 is formed.

In FIG. 30B, the light beam 398 from the subject moves parallel to the fixed optical axis FIX. However, in normal photographing, the distance from the camera body to the subject is sufficiently large. Therefore, the above translation component hardly affects the image formation position on the image sensor 402.

As described above, according to the present embodiment, the floating follow-up type optical system 408 and the fixed system 41 satisfying the tilt follow-up condition
By working with an inertial stabilizing member such as a gyro applied to 2, the image blur can be efficiently prevented.

[0472] The floating follow-up type optical system 4 of the present embodiment.
As 08, for example, a floating-following optical system as described in the first to third and fifth to ninth embodiments may be used. In particular, by configuring an image blur prevention camera using the same floating-following optical system as in the second and third embodiments, and an imaging unit including a reflection optical system instead of the imaging lens 400, Since the entire optical system can be composed of a reflective optical system, chromatic aberration can be eliminated.

The optical system applied to the present embodiment can be applied to various lens types, lens forms, and lens materials. The same is true.

The following technical ideas are derived from the above specific embodiments.

(1) A fixed system having a fixed optical axis fixed mechanically, at least one optical element belonging to the fixed system, and at least one free mechanical movement with respect to the fixed system. An optical system comprising a floating system having a floating optical axis having a degree, and at least one or more optical elements belonging to the floating system, wherein the first optical element on which a light beam from the fixed system first enters is provided. The last optical element that belongs to the floating system, and finally enters, belongs to the fixed system, and the N-th N-th optical element counted from the first optical element is connected to the fixed system when N is an even number. Belong to, N
When is an odd number, in a state where the relationship belonging to the floating system is satisfied, even if the floating optical axis fluctuates arbitrarily with respect to the fixed optical axis by displacing the floating system with respect to the fixed system, A floating-following optical system, wherein a light ray incident on the first optical element along a fixed optical axis belonging to the fixed system is always emitted from the last optical element along the floating optical axis.

(2) As the optical element, at least one
The floating tracking optical system according to (1), wherein at least one afocal optical system is used.

(3) As the optical element, at least 2
In the case of using a total of k or more and even number of afocal optical systems, the angular magnification of the first afocal optical system corresponding to the first optical element is γ1, and the first afocal optical system corresponds to the N-th optical element. When the angular magnification of the N-th afocal optical system is γN, and the angular magnification of the k-th afocal optical system corresponding to the final optical element is γk,

(Equation 6)

The floating following optical system according to (2), wherein at least one of the expressions (I-1) and (I-2) having the following relationship is satisfied.

(4) The optical system is composed of at least four or more optical elements, the power of the N-th optical element is φ _N , and the power of the N-th optical element is N + 1 from the rear principal point of the N-th optical element.
'When, (e _1' the distance to the front principal point of the optical element _{e N · φ 1 · φ 2} ) -φ 1 + (e 1 '+ e 2') φ 1 · φ 3 - (e 1 '· _{e 2 '· φ 1 · φ} 2 · φ 3) -φ 3 + φ 4 = 0 ... (I-3) φ 3 = (e 1' + e 2 ') -1 + (e 3') -1 ... (I -4) φ ₄ = − (e ₁ ′ + e ₂ ′ + e ₃ ′) ⁻¹ + (e ₃ ′) ⁻¹ (I-5) The above-mentioned formulas (I-3) to (I-5) having the relationship of (I-5) )), At least the formula (I-3) or the formula (I-
The floating-following optical system according to (1), wherein one of (4) and (I-5) is satisfied.

(5) As the optical element, at least one
(1) characterized by using at least two reflective optical elements
3. The floating following optical system according to 1.

(6) As the optical element, at least one
The floating tracking optical system according to (1), wherein at least one hologram optical element is used.

(7) A mechanically fixed fixed system, at least two or more floating systems having independent degrees of freedom with respect to mechanical movement with respect to the fixed system, and at least two or more (1) An optical device, comprising: a floating-following optical system according to (1), wherein, of the fixed system and the floating system, adjacent systems are optically connected by the floating-following optical system.

(8) At least one vibration isolation table, a first optical device installed on the vibration isolation table, and one optical system by being optically connected to the first optical device. A second optical device installed on the anti-vibration table or a fixed table, and the floating-following optical system described in (1), wherein the first optical device An optical device, wherein the optical system is optically connected to the second optical device by the floating tracking type optical system.

(9) The optical device according to (8), wherein a laser microscope device main body is used as the first optical device, and a laser oscillator is used as the second optical device.

(10) The optical device according to (8), wherein a semiconductor exposure apparatus body is used as the first optical device.

[0486]

According to the present invention, at least one of the translational component and the tilt component of the optical axes can be obtained even if the optical axes mutually shift mechanically due to the relative displacement of the plurality of optical systems. By optically correcting one of them, it is possible to provide a floating-following optical system having a simple configuration capable of suppressing the deviation between the optical axes within an allowable range and suppressing the occurrence of chromatic aberration. .

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a thin lens model according to the principle of the present invention.

FIG. 2 is a diagram showing a configuration of an afocal optical system model according to the principle of the present invention.

FIG. 3 is a diagram showing a configuration in a case where a thin lens belongs to a floating system in a thin paraxial tracking model according to the principle of the present invention.

FIG. 4 is a diagram showing a configuration in a case where a thin lens belongs to a fixed system in a thin paraxial tracking model according to the principle of the present invention.

FIG. 5 is a diagram showing a configuration in a case where an afocal optical system belongs to a floating system in an afocal optical system tilt model according to the principle of the present invention.

FIG. 6 is a diagram showing a configuration in a case where an afocal optical system belongs to a fixed system in an afocal optical system tilt model according to the principle of the present invention.

FIG. 7 is a diagram showing a configuration in a case where an afocal optical system belongs to a floating system in a focal optical system translation model according to the principle of the present invention.

FIG. 8 is a diagram showing a configuration in a case where an afocal optical system belongs to a fixed system in a focal optical system translation model according to the principle of the present invention.

9A is a diagram showing a state in which a floating system is translated with respect to a fixed system in a thin lens model according to the principle of the present invention, and FIGS. 9B and 9C are diagrams showing the state of the principle of the present invention. FIG. 9 is a diagram showing a state in which the floating system is tilted and displaced with respect to the fixed system in the thin lens model.

FIG. 10 is a diagram illustrating a configuration of a floating tracking optical system according to the first embodiment of the present invention.

FIG. 11 is a diagram showing a configuration of a floating tracking optical system according to a second embodiment of the present invention.

FIG. 12 is a diagram showing a configuration of a floating tracking optical system according to a modification of the second embodiment of the present invention.

FIG. 13 is a diagram showing a configuration of a floating tracking optical system according to a third embodiment of the present invention.

FIG. 14 is a diagram showing a configuration of a floating tracking optical system according to a fourth embodiment of the present invention.

FIGS. 15A and 15B are diagrams showing a configuration of a floating-following optical system according to a fifth embodiment of the present invention, wherein FIGS.
FIG. 9 is a diagram showing paraxial tracking results when the floating optical axis is displaced with respect to the fixed optical axis.

FIGS. 16A and 16B are diagrams for explaining a method of appropriately determining the distance between the afocal optical systems, where FIG. 16A is a diagram showing a state in which the floating system is translated with respect to the fixed system, and FIG. )
FIG. 3 is a diagram showing a state in which the floating system is tilted and moved with respect to the fixed system.

FIG. 17 shows the order of positive, negative, negative,
FIG. 7A is a diagram illustrating a state in which the interval setting method is applied to a floating following optical system having a positive angular magnification, and FIG.
A diagram showing a state in which the floating system has been translated with respect to the fixed system,
(B) And (c) is a figure which shows the state in which the floating system inclined and moved with respect to the fixed system.

18A is a diagram illustrating a configuration of a floating tracking type optical system including a thick lens, and FIG. 18B is a diagram illustrating a paraxial tracking result of a thick lens model.

FIG. 19 is a diagram showing a configuration of a floating-following optical system according to a sixth embodiment of the present invention. FIG. 19 (a) shows that the floating optical axis is displaced in parallel with respect to the fixed optical axis. FIGS. 7B and 7C are diagrams showing paraxial tracking results in the case, and FIGS. 7B and 7C are diagrams showing paraxial tracking results when the floating optical axis is displaced in inclination with respect to the fixed optical axis.

FIG. 20A is a diagram illustrating a configuration of a floating-following optical system according to a seventh embodiment of the present invention, and FIG. 20B is a diagram illustrating a state in which the floating system is tilted and displaced.

FIG. 21A is a diagram showing a state in which a floating system is displaced in parallel with respect to a fixed system in a floating tracking type optical system according to a seventh embodiment of the present invention, and FIG. Magnification is -1
FIG. 3C shows a relationship between an incident light beam incident on the afocal optical system and an outgoing light beam emitted from the afocal optical system. FIG. FIG.

FIG. 22 is a diagram illustrating a configuration of a floating tracking optical system according to an eighth embodiment of the present invention.

FIG. 23 is a diagram showing a configuration of a floating following optical system according to a ninth embodiment of the present invention.

FIG. 24A is a diagram illustrating a configuration of a floating tracking optical system according to a tenth embodiment of the present invention, and FIG. 24B is a diagram illustrating a state where the floating system is displaced with respect to a fixed system. .

FIG. 25 is a diagram showing a configuration of a floating tracking optical system according to an eleventh embodiment of the present invention.

FIG. 26 is a diagram showing a configuration of a floating tracking type optical system according to a twelfth embodiment of the present invention.

FIG. 27 is a diagram showing a configuration of a floating tracking optical system according to a thirteenth embodiment of the present invention.

FIG. 28 is a diagram showing a configuration of a floating following optical system according to a fourteenth embodiment of the present invention.

FIG. 29 is a diagram showing a configuration of a floating following optical system according to a fifteenth embodiment of the present invention.

FIG. 30 is a diagram showing a configuration of a floating following optical system according to a sixteenth embodiment of the present invention.

[Explanation of symbols]

AFC ₁ First afocal optical system AFC ₂ Second afocal optical system L ₁ First thin lens L ₂ Second thin lens L ₃ Third thin lens L ₄ Fourth thin lens

Claims (4)

[Claims] 1. A fixed system having a fixed optical axis that is mechanically fixed, at least one or more optical elements belonging to the fixed system, and at least one degree of freedom regarding mechanical movement with respect to the fixed system. An optical system comprising: a floating system having a floating optical axis having: and at least one optical element belonging to the floating system, wherein the first optical element on which light from the fixed system first enters is The last optical element that belongs to the floating system and that enters last belongs to the fixed system, and the N-th N-th optical element counted from the first optical element belongs to the fixed system when N is an even number. , N is an odd number in a state where the relationship belonging to the floating system is satisfied, and when the floating optical axis is arbitrarily changed with respect to the fixed optical axis due to displacement of the floating system with respect to the fixed system. Even the fixed Along said fixed optical axis belonging to the first light beam incident to the optical element is always floating-tracking optical system, characterized in that it is emitted from the final optical element along said floating optical axis. 2. The floating-following optical system according to claim 1, wherein at least one or more afocal optical systems are used as said optical elements. 3. When at least two and an even number of a total of k afocal optical systems are used as the optical element, the angle of the first afocal optical system corresponding to the first optical element is determined. Assuming that the magnification is γ1, the angular magnification of the N-th afocal optical system corresponding to the N-th optical element is γN, and the angular magnification of the k-th afocal optical system corresponding to the final optical element is γk, ] The floating-following optical system according to claim 2, wherein at least one of the expressions (I-1) and (I-2) having the following relationship is satisfied. 4. The optical system includes at least four or more optical elements, wherein the power of the N-th optical element is φ _N , and the N + 1-th optical element from the rear principal point of the N-th optical element. 'When, (e _1' the distance to the front principal point _{e N · φ 1 · φ 2} ) -φ 1 + (e 1 '+ e 2') φ 1 · φ 3 - (e 1 '· e 2 _{'· φ 1 · φ 2 ·} φ 3) -φ 3 + φ 4 = 0 ... (I-3) φ 3 = (e 1' + e 2 ') -1 + (e 3') -1 ... (I-4 ) Φ ₄ = − (e ₁ ′ + e ₂ ′ + e ₃ ′) ⁻¹ + (e ₃ ′) ⁻¹ (I-5) In the above formulas (I-3) to (I-5) Wherein at least the formula (I-3) or the formula (I-
The floating-following optical system according to claim 1, wherein one of (4) and (I-5) is satisfied.