Source: https://patents.google.com/patent/DE69839419T2/en
Timestamp: 2019-12-06 06:07:40
Document Index: 555482573

Matched Legal Cases: ['art 11', 'art 11', 'art 11', 'art 11', 'art 11', 'art 59', 'art 59', 'art 59', 'art 59', 'art 59']

DE69839419T2 - Optical element - Google Patents
DE69839419T2
DE69839419T2 DE1998639419 DE69839419T DE69839419T2 DE 69839419 T2 DE69839419 T2 DE 69839419T2 DE 1998639419 DE1998639419 DE 1998639419 DE 69839419 T DE69839419 T DE 69839419T DE 69839419 T2 DE69839419 T2 DE 69839419T2
DE1998639419
DE69839419D1 (en
Fumiaki c/o Canon Kabushiki Kaisha Kumagai
Makoto c/o Canon Kabushiki Kaisha Sekita
1997-12-02 Priority to JP33199797 priority Critical
1997-12-02 Priority to JP33199797 priority
1998-11-11 Priority to JP32095098A priority patent/JPH11231115A/en
1998-11-11 Priority to JP32095098 priority
1998-11-30 Application filed by Canon Inc filed Critical Canon Inc
2008-06-12 Publication of DE69839419D1 publication Critical patent/DE69839419D1/en
2009-09-10 Publication of DE69839419T2 publication Critical patent/DE69839419T2/en
The The present invention relates to an optical element for use in a video camera, a still camera, a copying machine and the like, In particular, it relates to an optical element having a plurality reflective surfaces with curvatures.
Usually, according to 29 used as a photographic recording optics with a reflective surface, a so-called mirror lens system.
As in 29 is shown becomes object light 174 from a concave mirror 171 bundled and reflected toward the object side and there on an image plane 173 displayed. This mirror objective system is based on the arrangement of a so-called Cassegrain reflecting telescope and aims at a low total objective length by folding the beam path of a telescope lens system of large objective length by using two mutually opposing reflection mirrors.
In A lens system of a telescope is in addition to the mentioned Cassegrain type also numerous systems for shortening the total optical length by using multiple reflection mirrors. Accordingly folded one the optical path effectively using a reflection mirror in a lens system with big ones Lenses total length, to thereby obtain a compact optical system.
In general, however, from the concave mirror 172 The Cassegrain reflector telescope darkens some object light rays.
This problem arises from the fact that a main beam 176 of the object light 174 on an optical axis 175 located. To solve this problem, numerous optical mirror systems have been proposed which are the main beam 176 of the object light 174 using a reflection mirror at a decentered position from the optical axis 175 move away.
According to a known method for moving the principal ray of the object light away from the optical axis, a part of a reflection mirror which is rotationally symmetrical with respect to the optical axis is used; U.S. Patent 3,674,334 and 4,737,021 etc. In addition, there is a method of decentering the central axis of the reflection mirror from the optical axis itself, cf. U.S. Patent 4,265,510 and 5,063,586 Etc..
30 shows an example according to the U.S. Patent 3,674,334 with respect to a method of utilizing a portion of a rotationally symmetric reflection mirror.
According to 30 are a concave mirror 181 , a convex mirror 182 and a concave mirror 183 originally with respect to an optical axis 184 arranged rotationally symmetrical, as shown by a double dot-dash line. But because the concave mirror 181 only its area above the optical axis 184 used, makes the convex mirror 182 only from its part below the optical axis 184 Use while the concave mirror 183 again only its section below the optical axis 184 used so that the main beam of the object light 185 from the optical axis 184 can be removed and the object light 185 is output without shading.
31 shows an embodiment according to the U.S. Patent 5,563,586 as an example of the method for decentering the center axis of the reflection mirror with respect to the optical axis.
If according to 31 an axis perpendicular to the object plane 191 as an optical axis 197 is defined, the center coordinates and the center axes of the surfaces of a convex mirror 192 , a concave mirror 193 , a convex mirror 194 and a concave mirror 195 opposite the optical axis 197 decenter, and the object light 198 can be effectively on an image plane 196 without being obscured by reflection mirrors, by properly adjusting the decentration measures and the radii of curvature of the respective surfaces.
By decentering the reflecting mirrors of the mirror optics in this manner, it is possible to prevent object light from being obscured. However, since the individual reflection mirrors have to be adjusted with different decentration measures, one obtains a complicated structure for the attachment of each The reflection mirror, and it is extremely troublesome to ensure a high mounting accuracy.
When a method of solution This problem will be in training a mirror system, for example in the form of a block assembly error for the optical parts when Assembly avoided. Are known conventional optical systems with a big one Number of reflective surfaces in block form, for example optical prisms, such as a pentachragon prism, a Porro prism and the like used in camera viewfinder systems be a Farbseparierprisma for separating a light beam from a photographic lens in three light beams of colors Red Green and blue, and for imaging object images based on the respective color light rays, on the respective imaging element surfaces.
The function of a pentachragon prism, which is widely used in single-lens reflex cameras, is an example of the optical prism which will be described below with reference to FIGS 32 is explained.
In 32 reference numbers 201 a shooting lens, 202 a folding mirror, 203 a focal plane, 204 a condenser lens, 205 a pentachragon prism, 206 an eyepiece, 207 the pupil of the observer, 208 an optical axis and 209 an image plane.
Light rays coming from an object (not shown) pass through the taking lens 201 , be inside the camera at the folding mirror 202 reflected and on the focal plane 203 pictured, located at one to the image plane 209 equivalent position.
Behind the focal plane 203 is the condenser lens 204 for imaging the exit pupil of the taking lens 201 on the pupil 207 the viewer. Behind the condenser lens 204 there is the pentachragon prism 205 to reverse the in the focal plane 203 located object image in an upright image.
One through the object light that enters the pentachragon prism 205 over an entrance area 205a is incident, defined object image is from the prism roof surface 205b laterally reversed. Subsequently, the object light from the reflective prism surface 205c reflected to the viewer.
The object light reflected to the observer side passes through the exit surface 205d of the pentachron prism 205 and reaches the eyepiece 206 , which converts the object light by its refractive power in almost collimated light. The nearly collimated light beam then reaches the pupil 207 of the viewer, so that the viewer can view the object image.
When a major problem of such optical prisms, for which the Penta pentagonal prism representative is very easily harmful Ghost light because of an irregular Light incidence in the prism from other locations and angles than the effective light rays.
In the pentachragon prism having the structure described above, ghost light incident on the prism at an angle different from the angles of the effective light rays, such as that in FIG 32 marked by the arrow, from the roof surface 205b and the reflective surface 205c is reflected, then from the entrance surface 205a totally reflected and then leaves the prism in the lower part of the exit surface 205d in the direction of the viewer. When such ghost light is generated, a vertical image appears on the lower side of the viewing frame because the frequency of reflections is different from that of the normal effective light rays.
To eliminate the ghost light is at the exit surface 205d of the pentachron prism 205 a light shielding groove 200 educated.
By blackening the entire prism surface except the entrance surface 205a and the exit surface 205d in the form of a on the roof surface 205b and the reflective surface 205c applied reflective film can be a protection against environmental changes to achieve, for example, temperature, humidity and the like by the light rays coming from outside the prism are intercepted. Since such an optical prism has a plurality of integrally formed reflecting surfaces, and the respective reflecting surfaces have a very precise relative positional relationship to each other, a positional adjustment is unnecessary.
Note that the main function of such a prism is to reverse an image that you change the direction of the light beam path, the individual reflective surfaces are defined by planes.
In contrast, for example, in the U.S. Patent 4,775,217 and the Japanese Patent Laid-Open Publication 2-297516 , compare also the EP-A-0 730 169 discloses optical prisms whose reflective surfaces have curvatures.
The U.S. Patent 4,775,217 relates to a structure of an eyepiece in a viewing optics. In the structure according to this document is in accordance with 23 from an information display element 211 upcoming indicator light 215 on a reflective surface 212 to the object side reflects and reaches an area 213 with a curvature defining a concave surface.
Due to their refractive power, the concave surface transforms 213 that of the information display element 211 as a divergent light coming indicator light 215 in almost collimated light and directs the light to the pupil 214 of the viewer so that the viewer can view the displayed image.
at The structure according to this document can also be an object image Viewing the displayed image.
Objektlicht 216 which is in a plane 217 that are nearly parallel to the reflective surface 212 runs, enters, reaches the concave surface 213 , For example, a semi-transparent film on the concave surface 213 depressed, some object light happens 216 the concave surface 213 and the other light component is reflected. The transmitted object light 216 reached over the reflective surface 212 the pupil 214 the observer. In this way the observer can see the object light 216 and the indicator light 215 Looking at each other, look at each other. In addition, the refers Japanese Patent Laid-Open Publication 2-297516 on the construction of an eyepiece in a viewing optics. In the structure according to this article according to 34 becomes an indication light coming from an information display element (not shown) 224 as collimated light through a plane surface 227 passed through and meets a parabolic surface 221 ,
The parabolic surface 221 focuses the indicator light 224 forming an image in a focal plane 226 ,
Since now the focused indicator light 224 the focal plane 226 achieved while it is between the plane surface 227 and a plane surface 228 parallel to this plane 227 is totally reflected, a low-profile structure of the entire optical system is achieved.
That from the focal plane 226 as a divergent light coming indicator light 224 meets a parabolic surface 222 where it is between the plane surfaces 227 and 228 is totally reflected. The parabolic surface 222 converts the indicator light 224 translates into nearly collimated light and directs it to the pupil 223 the viewer, so that he can recognize a displayed image.
In the cited document, the viewer can also see an object as well as look at the displayed image, similar to the structure according to the U.S. Patent 4,775,217 ,
Since such curved-surface optical prisms normally suffer more from optical performance degradation due to decentering of each reflective surface, compared to an all-plane surface optical prism, the allowable registration accuracy for each reflective surface is extremely stringent. However, neither mention the U.S. Patent 4,775,217 still the Japanese Patent Laid-Open Publication 2-297516 no adjustment method, assembly method, manufacturing method and the like with respect to the reflecting surfaces for precise compensation because of the positional accuracy of each reflecting surface.
If on the other hand, the number of reflective surfaces of an optical prism increases, the decentration amounts of the respective accumulate reflective surfaces due to the aberration correction of the optical prism. consequently becomes the allowed one Decentration measure per reflective surface smaller and stronger limited, when the number of reflective surfaces increases. For this reason A method is needed that accurately matches the registration accuracy because of every reflective surface can be compensated.
Furthermore These optical prisms are formed by molding using a metal mold manufactured to meet the cost requirements of modern manufacturing.
For example, a pentachragon prism, which is usually made by polishing a glass block, formed by means of a metal mold as a so-called hollow pentagonal prism, wherein the reflective surfaces 205b and 205c to 32 formed by reflecting mirrors and are formed integrated in conjunction with a hollow prism. When forming a hollow pentagonal prism, the imaging performance of the viewfinder system is maintained regardless of small positional deviations of the reflection mirrors, because the reflection mirrors are formed exclusively by flat surfaces.
If Furthermore an optical prism with curved reflective surfaces is formed by molding, a metal mold is required a greater positional accuracy for every reflective surface requires as the optical prism planning exclusively surfaces has.
If furthermore an optical prism with curved reflecting surfaces Molds is needed one has a metal mold structure, which is a complicated optical system, which integrates with several reflective and curvatures equipped with decentered surfaces wearing.
The The present invention has been made in view of the above problems made, and it is their goal, the relative decentering more reflective surfaces, the highest Have to have accuracy, to suppress an impairment the optical power in an optical element in which several reflective surfaces with curvatures are arranged adjacent to each other to prevent.
It Another object of the invention is the degree of freedom in aberration correction of an optical element to increase and the imaging performance of the optical element improve.
One Another object of the invention is the distance between reflection surface blocks Precise set points and simultaneously the production to simplify the respective reflection surface blocks.
One Another object of the invention is the prevention of occlusion effective light rays in an optical element.
One Another object of the invention is the reduction of the number of parts in order Reduction of errors when moving an optical element under simultaneous prevention of coverage of effective light rays in an optical element.
It is yet another object of the invention, a cheap optical To create element, which are produced by molding can, independently from its shape with reflective surfaces at exact locations.
One Another object of the invention is to provide an optical element, which suffers less ghost light.
One Another object of the invention is the directions of light rays, which enter an optical element and leave it, arbitrarily adjust.
These Goals are achieved while overcoming the specified Problems with the methods of making an optical element according to claim 1 and by the optical element according to claim 25. The rest claims refer to further developments.
Further Goals and benefits except those already discussed above will be apparent to those skilled in the art from the following Description of a preferred embodiment of the invention. In the description is made to the accompanying drawings, which are part of the present disclosure, and which are an example illustrate the invention. This example is not exhaustive for different embodiments of the invention so that reference is made to the claims appended to the description should be taken to determine the scope of the invention.
1 Fig. 12 is a diagram for explaining the coordinate system illustrating the positions and the refractive or reflection angles of the surfaces of the respective optical elements according to the invention;
2 Fig. 10 is a sectional view of the optical path for explaining the first embodiment of the invention;
3 Fig. 15 is a perspective view of an optical element of the first embodiment;
4 Fig. 12 is a perspective view for explaining the method of assembling a reflection surface block of the first embodiment;
5 Fig. 12 is a perspective view for explaining the method of holding the reflection surface block of the first embodiment;
6 Fig. 16 is a perspective view for explaining another method for holding the reflection surface block of the first embodiment;
7 Fig. 15 is a perspective view for explaining the second embodiment of the invention;
8th Fig. 12 is a perspective view for explaining the third embodiment of the invention;
9 Fig. 15 is a perspective view for explaining the fourth embodiment of the invention;
10 Fig. 12 is a view for explaining an example of a metal mold structure according to the invention;
11 Fig. 12 is a view for explaining the method of processing a metal mold used to form a first reflecting surface block;
12 Fig. 12 is a view for explaining the method of processing a metal mold used to form a first reflecting surface block;
13 Fig. 12 is a view for explaining an example of a metal mold structure according to the invention;
14 Fig. 12 is a view for explaining an example of a metal mold structure according to the invention;
15 Fig. 10 is a sectional view for considering a section through the optical path in an actual configuration, as viewed from the -Z axis direction;
16 Fig. 10 is a sectional view for considering a section through the optical path in an actual configuration, as viewed from the + Z-axis direction;
17 shows numeric data for the current design example;
18 Fig. 10 is a sectional view of the optical path for explaining the sixth embodiment of the invention;
19 FIG. 15 is a perspective view for explaining the sixth embodiment; FIG.
20 Fig. 12 is a perspective view for explaining the method of holding a reflection surface group of the sixth embodiment;
21 Fig. 12 is a perspective view for explaining the method of holding a reflection surface group of the sixth embodiment;
22 Fig. 15 is a perspective view for explaining a seventh embodiment;
23 Fig. 12 is a view for explaining an example of a metal mold structure in the scope of the invention dung;
24 Fig. 12 is a view for explaining the method of working a metal mold;
25 Fig. 12 is a view for explaining an example of a metal mold structure in the invention;
26 Fig. 10 is a sectional view for considering an optical-axis section of a current design example viewed from the -Z axis direction;
27 Fig. 10 is a sectional view for considering a section of an optical axis of a current design example viewed from the + Z-axis direction;
28 shows numeric data for the current design example;
29 is an illustrative representation of a conventional optical reflection system;
30 is an illustrative representation of another optical reflection system;
31 is an illustrative representation of a still further optical reflection system;
32 is an illustrative representation of a conventional optical prism;
33 Fig. 10 is an exemplary view of a conventional viewing optical system; and
34 is a vivid illustration of another optical viewing system.
The preferred embodiments The invention will be described below. Before a detailed Description of the embodiments becomes a method of creating numerical data of each embodiment explains being for all embodiments common terms are used.
1 is an illustrative representation of the coordinate system, which defines numerical data of an optical system according to the invention. In each embodiment of the invention, an area located at the i-th point along a light beam (in 1 represented by a single-dashed line and hereinafter referred to as a reference axis light beam), which runs from the object side in the direction of the image plane, referred to as an ith surface.
To 1 For example, a first surface R1 is an aperture, a second surface R2 is a reflective surface having a slope opposite to the first surface R1, and third and fourth surfaces R3 and R4 are reflective surfaces having displacements and inclinations opposite to the immediately preceding surface, respectively. The reflection surfaces form an optical element B1.
There the optical system according to the invention is a decentering optical system, the individual need surfaces, which make up the optical system, no common optical axis to own. For this reason, in each embodiment the invention an absolute coordinate system originating in the Center of the effective light beam diameter of a first surface set.
at each embodiment The invention will be the center of the effective light beam diameter of first surface set as the origin, and the path of a light beam (reference axis light beam), that through the origin and through the middle of a final image plane is defined as the reference axis of the optical system. Furthermore For example, the reference axis of each embodiment of the invention has one direction (Orientation). The direction coincides with that direction which passes through the reference axis light beam in the image.
at each embodiment The invention relates to the reference axis of the optical system in the set above manner. However, at the method of setting the reference axis of the optical system also one for the optical design, an aberration correction matching axis or an axis for the description of the respective surface forms of the optical system be used.
Generally however, a path on which a light beam (reference axis light beam), which passes through the center of the first surface of the optical system and the middle of the final Image plane is reached, is reflected by the reflection surfaces, as Reference axis set up. The order of the respective areas is in any case set up so that in this order the Reference axis light beam suffers a reflection.
consequently Finally, the reference axis reaches the center of the image plane under change his direction according to one Law of reflection in the predetermined order of the individual Surfaces.
Any inclined or tilted surfaces that make up the optical system of any embodiment of the invention basically have slopes in an identical plane. For this reason, the respective axes for the absolute coordinate system are defined as follows:
Z-axis: a reference axis through the origin, which extends to the second surface R2.
Y-axis: a straight line through the origin, which with respect to the Z-axis in a plane of inclination (the plane of the drawing 1 ) describes an angle of 90 ° counterclockwise.
X axis: a straight line through the origin perpendicular to the Z and Y axes (a straight line perpendicular to the plane of the drawing) 1 ).
Around the shape of the i-th surface express which forms the optical system, it is easy to see that the shape can be set by setting up a local coordinate system, whose origin is the intersection between the reference axes and the i-th surface is, taking the surface shape through this area the local coordinate system is described instead of the surface is described using the absolute coordinate system. For this reason, in one embodiment, the numerical Data of the invention uses the surface shape of the ith surface described the local coordinate system.
The inclination angle of the ith surface in a YZ plane is expressed by an angle θi (°) that is positive counterclockwise with respect to the Z axis of the absolute coordinate system. Thus, in each embodiment of the invention, the origin of the local coordinate system of each face is located on the in 1 shown YZ-plane.
There is no surface centering in the XZ and XY planes. In addition, the y and z axes of the i-th area local coordinate system (x, y, z) are tilted at an angle θi in the absolute coordinate system (X, Y, Z) in the YZ plane and set as follows:
z-axis: a straight line through the origin of the local coordinate system, forming an angle θi counterclockwise with respect to the Z-direction of the absolute coordinate system in the YZ plane.
y-axis: a straight line through the origin of the local coordinate system, forming an angle of 90 ° counterclockwise with respect to the z-direction in the YZ plane.
x-axis: a straight line through the origin of the local coordinate system at right angles to the YZ-plane.
Besides that is Di the scalar size, the the distance between the origin points of the local coordinate system the i-th and (i + 1) -th surface represents and Ndi and νdi are the refractive index and the Abbe number of a medium between the i-th and the (i + 1) -th surface.
Each embodiment of the invention has a spherical surface and a rotational asymmetric aspherical surface. Of these surfaces, the spherical shape of the spherical part is described by a radius of curvature Ri. The radius of curvature Ri has a minus sign when the center of curvature is on the side of the first surface along the reference axis (the broken line in FIG 1 ) extending from the first surface toward the image plane, it has a plus sign when the center of curvature is on the side of the image plane.
It should be noted that the spherical surface has a shape according to the following equation:
The optical system according to the invention has at least one rotationally asymmetric, aspherical surface whose shape is given by the relationship: z = A / b + C02y 2 + C20 x 2 + C03y 3 + C21 x 2 y + C04y 4 + C22 x 2 y 2 + C40 x 4 For
Since the above curved-surface formula has even-order terms exclusively for x, an area defined by the above curvature surface formula has a plane symmetric shape with the yz plane as the plane of symmetry. In addition, if the following condition is satisfied, the curved surface has a spherical shape with respect to the xz plane: C 03 = C 21 = t = 0
Otherwise owns the curved area a rotationally asymmetric shape.
In addition, if the following condition is satisfied, the curved surface has a rotationally symmetrical shape. C 02 = C 20 , C 04 = C 40 = C 22 / 2
In each embodiment of the invention forms according to 1 the first surface (the entrance side of the optical system) the aperture. In addition, a horizontal half-field angle uY is the maximum field angle of a light beam entering the aperture R1 in the in 1 shown YZ-level occurs. The diameter of the aperture as the first surface is represented by the aperture diameter.
This refers to the brightness of the optical system. The aperture diameter corresponds to the diameter of the entrance pupil, since the latter is on the first surface located.
Farther The effective image area in the image plane is described as image size. The picture size is expressed out by a rectangular zone whose horizontal and vertical Dimensions expressed are given by corresponding values in the y and x direction of the local Coordinate system.
2 Fig. 10 is a sectional view through the optical path of the first embodiment. reference numeral 1 denotes an example of an optical element formed integrally or integrally with a plurality of reflecting surfaces having curvatures, in particular, forming an optical element having five reflecting surfaces, namely, a concave mirror R2, a convex mirror R3, a concave mirror R4 , a convex mirror R5 and a concave mirror R6 as viewed from the object side. The reference axis, which is in the optical element 1 occurs, and the reference axis, which leaves this, run anti-parallel to each other. reference numeral 2 denotes an optical correction plate, for example, a quartz low pass filter, an infrared cut filter or the like, 3 denotes an imaging element surface, such as a CCD; 4 denotes one on the object side of the optical element 1 located aperture and 5 denotes a reference axis of the photographic optical system.
The mapping relationship of this embodiment will be explained below. Light coming from an object 6 meets the concave mirror R2 of the optical element 1 after the light passes through the aperture 4 was limited.
The concave mirror R2 reflects the object light 6 to the convex mirror R3 and forms a primary object image in an intermediate image plane N1.
Because the object image in this way at an early stage within the optical element 1 is generated, there is an increase in the effective light beam diameter of the on the image side of the diaphragm 4 suppress the surface.
The object light 6 which generates a primary image in the intermediate image plane N1 generates an image on the pixel surface 3 after repeated reflection by the convex mirror R3, the concave mirror R4, the convex mirror R5 and the concave mirror R6, influenced by the reflection forces of the reflection mirrors.
In this way, the optical element is used 1 as a lens unit having the desired optical performance and a positive optical force as a whole, at the same time, repeats reflections on a plurality of bends having reflection curvatures.
3 is a perspective view of the in 2 shown optical element.
Like reference numerals refer to FIG 3 the same parts as in 1 ,
In this embodiment, the optical element 1 formed by reflecting surface blocks, each of which integrates a plurality of adjacent reflecting surfaces with bends, being placed at opposite positions.
Referring to 3 form the concave mirror R2 as the first reflection surface of the optical element 1 , the concave mirror R4 as the third reflection surface and the concave mirror R6 as the fifth reflection surface form a first reflection surface block integrally forming three reflection surfaces.
The convex mirror R3 as the second reflection surface of the optical element 1 and the convex mirror R5 as the fourth reflection mirror, which is the first reflection surface block 7 opposite form a second reflection surface block 8th which integrally includes two reflecting surfaces. The first and the second reflection surface block 7 and 8th form the optical element 1 ,
On that way themselves by using reflecting surface blocks, each adjacent reflective surfaces integrated, which are placed in decentered places, the time for the Assembly shortened and layout errors in assembly can be reduced compared to the individual reflection surfaces that are at predetermined decentered places need to be placed because the integrated Reflection surface blocks only are to be placed at predetermined locations.
If the reflection surfaces each reflection surface block be formed integrally using a metal mold, let yourself a high positional accuracy and surface precision of the individual reflection surfaces independent of Guarantee production quantities, and the high positional accuracy of the reflection mirrors, in the conventional System is difficult to achieve, can be done in a simple way to reach.
In this case, the first and the second reflection surface block 7 and 8th either integrated or manufactured separately using a metal mold. However, in view of the method of forming a reflection film on each reflection surface by deposition, sputtering, dipping or the like after forming each reflection surface block, it is preferable to form the reflection surface blocks separately and the first and second reflection surface blocks 7 and 8th to combine with each other, after on each reflection surface by deposition, sputtering, dipping or the like, the reflection film was formed.
As a method of combining the first and second reflecting surface blocks 7 and 8th which have been manufactured by means of a metal mold separated from each other, according to, for example 4 spigot 9a to 9d extending from the first reflection surface block 7 in the direction of the second block 8th extend at such locations where they do not have the effective light rays of the optical element 1 obstruct, and cones 10a to 10d extending from the second reflection block 8th towards the first block 7 extend at those points where they the light rays of the optical element 1 do not interfere with being united with each other by the distance between the first and the second reflection surface block 7 and 8th to hold at a set point. Alternatively, the free end portions of the pins 9a to 9d at the first reflecting surface block 7 act as pins, while at the free ends of the pins 10a to 10d of the second block 8th Holes are formed, so that an assembly of the optical element 1 This is done by putting the pins and holes together.
These cones 9a to 9d and 10a to 10d are placed at predetermined locations of the reflective surface blocks. If the pins 9a to 9d and 10a to 10d are formed simultaneously by means of a metal mold, while the reflection surface blocks are formed, so can the operation of attaching the pin 9a to 9d and 10a to 10d Avoid at the relevant reflection surface blocks. Consequently, this also reduces the number of parts, which in turn reduces the production costs.
If the reflective surface blocks and the cones are created simultaneously using a metal mold, let yourself the length set up each peg according to the accuracy of the metal mold, and the distance between the opposing reflecting surface blocks can be exactly follow.
The pins are in an area outside the effective light rays of the optical element 1 united or coupled together. However, light other than the effective rays of light may strike these cones and cause ghost light.
In order to solve this problem, in this embodiment, light-shielding grooves are provided on the pins 9a to 9d and 10a to 10d formed to reflect incident light in directions other than the effective rays of light at the pins in the direction of the optical path, or the surface of each pin is subjected to a sand blasting process to diffuse light arriving at the pin and thus the formation of To avoid ghost light.
When the Lichtabschirmnuten or sandblasted sections of the pins 9a to 9d and 10a to 10d formed directly on the metal mold, a measure against the formation of ghost light can take place simultaneously with the formation of the reflection surface blocks.
If Furthermore using the optical element of this embodiment a zooming or focusing is performed, a holding part for fixing the optical element to a movable stage directly at the reflection surface block be formed, wherein the movement of the optical element to the moving stage considered becomes.
5 shows an example of a holding part for fixing, formed on the first reflection surface block.
How out 5 shows, is a holding part 11 on the back of the effective reflection surface of the concave mirror R4 of the first reflection surface block 7 designed such that its bottom surface 11a moving in a direction parallel to the reference axis 5 extending level. Zooming or focusing takes place in that this holding part 11 and a movable stage (not shown) are coupled and the movable stage is moved.
Since the the reference axis 5 containing plane parallel to the bottom surface 11a of the holding part 11 extends, the parallelism between the movable stage and the optical element in a simple manner ensure that the holding part 11 and the movable stage are coupled in parallel. For this reason, influences of decentering and the like of the reference axis upon movement of the optical element can be eliminated, thereby preventing deterioration of optical performance.
Note that the floor area 11a of the holding part 11 preferably has a mirror surface. In addition, the surface roughness of the bottom surface 11a preferably 0.08 μm or less (Rmax). When the floor area 11a polished to a surface roughness of about 1 to 2 μm (Rmax), the tip areas of the three-dimensional surface may be destroyed or shaved to parallelism with the reference axis 5 level, which in turn leads to a problem of decentration.
When another example of zooming and focusing using the optical element this embodiment can be made use of a method in which holes on the reference surface blocks of the optical element are formed, fitted into the holes a shaft and the optical element is moved along the shaft.
6 shows an example where the holes 13a and 13b holding a shank 12 record at the first and the second reflecting surface block 7 and 8th are formed.
To 6 are the holes 13a and 13b at the first and second reflecting surface blocks 7 and 8th formed at such locations, the same distances from the the reference axis 5 and are separated from a region of effective light rays of each reflection surface.
After fitting the shaft 12 in these holes 13a and 13b the reference axis remains 5 containing plane parallel to the shaft 12 , and the shaft 12 may serve as a guide in a movement of the optical element, such as in a translational movement of the optical element.
To 6 is only from a shaft 12 Use made, but it can also be used several shafts.
As already said, by forming a reflective optical Elements with the help of a metal mold this element several functions fulfill, For example, a hold function, a light shielding function and like, reducing the number of parts and the manufacturing cost can be and the functions and performance of the optical element can be improved.
The second embodiment will be described below with reference to FIG 7 explained. In this embodiment, another reflection surface block not facing the first and second blocks of the first embodiment is added to change the seals of the reference light beam incident in the optical element 1 enters and leaves this.
To 7 is a third reflection surface block 14 in the vicinity of the convex mirror R3 of the second reflection surface block 8th placed, he stands the first and the second reflection surface block 7 and 8th not opposite and has a slope of about 45 ° with respect to the incident reference axis, thus a reference axis 5a which enters from the + Z-axis direction of the first embodiment to enter from the -X-axis direction.
On the other hand, there is a fourth reflection surface block 15 in the vicinity of the convex mirror R5 of the second reflection surface block 8th , he stands the first and the second reflection surface block 7 and 8th not opposite, and he has an inclination of about 45 ° with respect to the incident reference axis, so that a reference axis 5b which comes off in the -Z-axis direction of the first embodiment, goes off in the + X-axis direction.
There in this embodiment the optical system formed by exclusively reflective surfaces is, unlike a conventional one System in which reflective mirrors in a refractive lens system added are to change the angle of light rays, the third and third the fourth reflection surface block, not facing the first and second reflecting surface blocks, added are and curvatures can show the directions in which a light beam enters the optical element and leaves it, with simultaneous correction easily change from aberrations.
at this embodiment can the reflection surface blocks, the adjacent to the first and second reflecting surface blocks, simultaneously with the formation of the first and second reflective surface blocks be formed.
Because For example, the third reflection surface block the second block is adjacent, he can using the for the second reflection surface block used metal mold.
Of course, after the third reflection surface block independently from the second block, a connection or attachment of the third block at the second reflecting surface block.
By adding a further reflection surface block, which is not opposite to the first and the second reflection surface block, in this way the entry and exit directions of the reference axis light beam can be freely adjusted. In a camera making use of the optical element of this embodiment, because entrance and exit directions are arbitrary, the size and the thickness of the camera can be reduced due to reduction of the dead space, and a camera can be provided with one Build form that was not seen before.
The third embodiment of the invention will be described with reference to FIGS 8th explained. In this embodiment, refracting members are disposed in the vicinity of the first and second reflecting surface blocks.
Referring to 8th is a refracting element 16 next to the convex mirror R3 of the second reflection surface block 8th of the first embodiment, and has positive refractive power.
On the other hand, in the vicinity of the convex mirror R5 of the second reflection surface block 8th a refractive element with negative refractive power.
at this embodiment let yourself by appropriate placement of the refractive elements and reflective Elements achieve an embodiment that is distinguished by the characteristics of individual elements. For example, the Refractive elements use of the refractive power of the entire optical Elements, while the reflective elements share an aberration correction To run. On that way increase the degree of freedom in the design of optics, and you can be an optical element with high performance achieve.
Usually are reflected in a built-up only by reflective elements optical system never chromatic aberrations, below referred to as a color defect caused. If, however, an optical Hybrid system is built, which is both reflective as well as making use of refracting elements arise in the Refraction elements color error.
Around to solve this problem, are in this embodiment Pairwise refractive elements with positive and negative refractive power inserted into the optical reflection system to eliminate color errors between cancel the two refractive elements. So of refraction elements Use is made possible achieve a color error correction of the entire optics.
If the refractive element is made of the same material as the Reflective surface block, can at the same time as the formation of the reflection surface block produce. However, the refractive element may be different from another Material as the reflection surface block be prepared to the above-mentioned color error correction make. In this embodiment the refractive element is on with positive refractive power the entrance side of the optical element, and the refraction element with negative refractive power is on the exit side. alternative can the refractive element with negative refractive power on the entrance side be placed, and the refractive element with positive refractive power may be on the exit side. Has the optical System vulnerability for considerable Color error, so you can pairwise refractive elements with both positive as well as negative refractive power instead of the pairwise refractive elements use with positive and negative refractive power, or you can only one refractive element with positive or negative Use refractive power.
If the refractive elements on the inlet side and the outlet side of the reflective optical system, they can act as covers to prevent the entry of dust into the optical system to prevent and thereby impair the image quality Prevent dust.
The following is based on the 9 the fourth embodiment is explained. In this embodiment, a refracting element is located in the vicinity of a reflection surface block which does not face the first and second reflection surface blocks.
To 9 is a third reflection surface block 15 in the vicinity of the convex mirror R5 of the second reflection surface block 8th not opposite to the first and second reflecting surface blocks 7 and 8th placed, and it has an inclination of about 45 ° with respect to the incident reference axis 5 , This block becomes the reference axis 5 extending in the direction of the -Z axis of the first embodiment, to a reference axis exiting the optical element in the direction of the ± X axis.
On the reference axis leaving the optical element in the + X-axis direction 5b is a refraction element 18 negative refractive power in the vicinity of the third reflection surface block 15 placed.
Normally, by bending the optical path, the distance from the last plane to the image plane inevitably decreases. In this embodiment, by synthesizing the third reflection surface block 15 and a refractive element 18 Correct a decrease in the rear focal length due to the bending of the optical path.
By Placing the refractive element near the reflection surface block let yourself in this way the degree of freedom in the optical design enlarge, the Lets picture performance improve, and the degree of freedom in the layout of the optical System leaves also increase. Furthermore may be an entry of dust into the reflective optical system be prevented.
The first example of a metal mold structure for forming the reflection surface blocks explained above will be described below in connection with FIG 10 explained.
10 is a sectional view of a metal mold 19 for forming the first reflection surface block 7 the first embodiment. The metal mold 19 consists of paired moldings 20 and 21 for the integrated formation of the concave mirror R2, the concave mirror R4 and the concave mirror R6 constituting the first reflection surface block.
Note that the metal mold unit 20 from three metal blocks 251 . 252 and 253 corresponding to the three reflecting surfaces, that is, the concave mirror R2, the concave mirror R4, and the concave mirror R6, which is the first reflecting surface block 7 form, and that the metal mold unit 21 also three metal mold blocks 261 . 262 and 263 contains, which correspond to the three reflective surfaces.
There in this embodiment Metal mold blocks corresponding to a plurality of reflecting surfaces with curvatures are present, the the respective reflection surface block form, and these blocks can be produced as units, the shapes for the metal mold can be design freely, even if the individual reflective surfaces are themselves located at decentered sites, creating an integrated training of the reflection surface block allows becomes.
There the metal mold blocks be made according to the individual reflective surfaces needs the processing limit opposite the zone of effective light rays used for normal metal forming is required not to be excessively estimated, and the distance limit between adjacent reflective surfaces can be minimize. Consequently lets also the size of the reflective surface block minimize as a group of reflective surfaces.
If however, a metal mold is divided into units of metal mold blocks will, so must the positions of the split metal mold blocks are precisely adjusted for a high registration among the divided metal mold blocks to guarantee. If every reflective surface has a strict registration is required, is preferably used by a metal mold made up of several reflective surfaces with curvatures in the form of a single continuous area having.
In particular, when the reflecting surfaces are close to each other, or when it is impossible to uniformly set the degree of gradation, the blocks constituting the reflecting surfaces must be separated. When the individual split reflecting surface blocks are made in correspondence with the effective light beam zones, these effective light beam zones have different shapes, for example, they are in the form of an ellipse, a polygon and the like based on a circle and a rectangle as shown in FIGS 15 . 16 . 26 and 27 In addition, they have various sizes corresponding to the amounts of the reflected effective light beams. When all the mirror surface shapes are standardized to a rectangular shape without being affected by various relations with the zones of the effective light beams, and the mirror surface processing area of each divided reflection surface block corresponding to that having the widest mirror surface area is determined, the quality of each block can be improved, and a high level can be achieved Accurate alignment when assembling the reflection surface blocks reach.
If however, the adjacent areas of the reflection surfaces of the Reflective surface blocks between can contain a step, so can several reflective surfaces can not be formed by a single continuous surface.
The reason for this difficulty is explained below on the basis of 11 and 12 explained.
11 is a schematic view in the event that the metal mold unit 20 with a grinding wheel 22 is polished.
Referring to 11 Let's assume that the metal mold blocks 252 and 253 corresponding to the concave mirrors R4 and R6 have a step between them. By and large, the grinding wheel has 22 a spherical shape and grinds each reflection surface on the metal mold. Because the grinding wheel 22 has a spherical shape, it can not come into contact with an edge region E passing through the metal mold blocks 252 and 253 is formed when the boundary areas between the metal mold blocks 252 and 253 are processed according to the concave mirrors R4 and R6. For this reason, the edge region E can not be ground to achieve an arrangement in which adjacent reflection surfaces form a single surface.
12 is a schematic view in the event that the metal mold unit 21 from the grinding wheel 22 is sanded. For the same reason as in 11 can not edit the edge area E.
Around To avoid these situations, the neighboring areas can be left out the respective reflection surfaces train so that there are no stages in the design between them. However, such a method is not preferred because the adjacent areas must have the same curvatures and consequently the degree of freedom in design is lower.
If in this embodiment the adjacent areas of the reflective surface forming the reflective surface blocks, between them contain a step, so are the adjacent areas outside the zones of effective light rays of the reflecting surfaces are formed, and they have shapes that make a smooth connection to the one being worked on reflective surfaces have, so that several reflective surfaces ultimately a single continuous area represent.
13 shows a second example of the metal mold structure of this embodiment. In this example, the concave mirrors R4 and R6 are the metal mold unit 20 through a neighboring area 23 smoothly connected to each other without coming to a step in a boundary area between the mirrors. Consequently, the metal mold unit can be made 20 form as a single continuous surface.
To 13 falls the neighboring area 23 from the effective zones of the concave mirrors R4 and R6, and its shape can be basically freely set as long as there is no blocking of the effective zones of the reflecting surfaces.
As a method of determining the shape of the neighboring area 23 For example, if the shape of the neighboring area 23 is defined for smoothly connecting the edges of the effective zones of the concave mirrors R4 and R6, the metal mold unit 20 formed by a single continuous surface without any edge areas arising through the grinding wheel 22 do not grind.
14 shows the third example of the metal mold structure of this embodiment. In this example, a neighbor area connects 24 the concave mirrors R4 and R6 of the metal mold unit 21 using the same procedure as in conjunction with 13 has been explained smoothly without formation of any step in the boundary region between the concave mirrors R4 and R6, so that the metal mold unit 21 is formed by a single continuous surface.
By Smooth connection of the adjacent reflection surfaces by means of areas outside of their effective zones itself in the manner described, the metal mold unit by a single continuous area produce, and with it leaves guarantee a high positional accuracy of the reflection surfaces.
15 and 16 are sectional views in the event that the in 2 shown optical element 1 from the -Z axis direction and the + Z axis direction. These sectional views also show the patterns of the zones of effective light rays of the respective reflection surfaces.
15 is a sectional view in the event that the optical element 1 from the -Z axis direction. To 15 owns the optical element 1 the concave mirror R2 as an entrance surface, the concave mirror R4 and the concave mirror R6 as the exit surface, which are formed adjacent to each other.
16 is a sectional view in the event that the optical element 1 from the + Z axis direction. To 16 owns the optical element 1 the convex mirrors R3 and R5 which are arranged adjacent to each other.
In examining the adjacent regions of the concave mirrors R2 and R4 in FIG 15 For example, the zone of the effective light beams of the concave mirror R2 is a trapezoidal-shaped zone, while the concave mirror R6 has a circular shape.
On the other hand, the respective reflection surfaces of the optical element 1 structurally considered to have rectangular shapes, like 15 As a result, when a reflection film is deposited on the entire reflection surface by deposition, sputtering, dipping or the like, this film must be formed in a wide zone outside the zones of effective light rays.
If from the optical element 1 caused ghost light, this is often due to incident light from locations and angles other than the locations and angles of the effective light rays, as a result of which the light rays often strike positions outside the effective light ray zones.
If Ghost light a detrimental Has influence on the optical properties and the efficiency impaired so this problem is solved by each reflection surface accordingly their effective light beam zone is formed while a Empty area of the reflection surface block, which makes use of a rectangular element of a size that the effective light beam zone completely covering, is provided below the block, thereby creating a high To ensure accuracy which happens with the help of the same alignment procedure as with the reflection surface block with a normalized rectangular shape.
If on the entire reflection surface A reflection film is formed with high probability Ghost light from a surface part outside the effective light beam zone, leaving the precipitation zone for the Reflection film is preferably largely reduced to ghost light to avoid.
In this embodiment, a reflection film is formed by deposition, sputtering, dipping or the like only on the in 15 a zone indicated by a dashed line is formed in a pattern nearly equal to the shape of the effective light beam zone of each reflection surface to obtain a predetermined edge area with respect to the effective light beam zone, thereby avoiding generation of ghost light by a zone other than the effective light beam zone.
In addition, in this embodiment, a zone other than the deposition areas in FIG 15 formed as a non-smoothed surface, for example in the form of a diffusion surface. By simultaneously forming this diffusion surface when the reflection surface block is formed, when ghost light caused by a surface area other than the effective light beam zone falls on a zone other than the deposition zone, the proportion of the ghost light is reduced by the diffusion effect of the diffusion surface, which reduces the intensity of the ghost light.
17 shows numeric data for a current design example.
in the The following will be the sixth embodiment of the invention explained.
18 Fig. 10 is a sectional view through the optical path of the sixth embodiment. reference numeral 51 denotes an example of an optical element which is integrated with a plurality of curved reflecting surfaces. The optical element formed by five reflection surfaces and two refractive surfaces 51 has a concave refracting surface R2, a concave mirror R3, a convex mirror R4, a concave mirror R5, a convex mirror R6, a concave mirror R7, and a convex refracting surface R8 viewed from the object side. The reference axis, which is in the optical element 51 enters, and the optical element 51 leaving reference axis are pa to each other rallel and have opposite course. reference numeral 52 denotes an optical correction plate, for example, a quartz low pass filter, an infrared cut filter or the like; 53 is an imaging element surface, such as a CCD; 54 is an aperture on the object side of the optical element 51 , and 55 denotes a reference axis of a photographic optical system.
The mapping relationship of this embodiment will be explained below. Light originating from an object 56 falls into the concave refraction surface R2 of the optical element 1 a, after the amount of light through the aperture 54 was limited.
The concave refracting surface R2 converts the incident object light 56 by their refractive power into divergent light, and the concave mirror R3 then reflects this light and images a primary object image on the intermediate image plane N1 due to its reflectivity.
Because in this way the object image in the optical element 51 is generated at an early stage, an increase in the effective light beam diameter on the image-side surface of the diaphragm 54 be suppressed.
The object light 56 which forms a primary image on the intermediate image plane N1 reaches the convex refracting surface R8, being reflected by the convex mirror R4, the concave mirror R5, the convex mirror R6 and the concave mirror R7, and influenced by the reflection forces of the respective reflection mirrors. The object light refracted by the refractive power of the convex refraction surface R8 56 forms on the image sensor element surface 53 an object image.
In this way, the optical element is used 51 as a lens unit having the desired optical performance and positive power as a whole, with repeated refractions on the entrance side and the exit side, and reflections on the plurality of bends having mirrors.
19 is a perspective view of the in 18 represented optical element.
Same reference numerals in FIG 19 stand for the same elements as in 18 ,
In this embodiment, the optical element 51 is formed by forming reflection surface groups on opposite surfaces of a transparent member, on each of which a plurality of adjacent reflection surfaces having bends are placed at adjacent positions, in addition to the pair of entrance and exit refraction surfaces.
To 19 are the concave mirror R3 behind the concave reflection surface, which receives the light coming from the object and as the first reflection surface of the optical element 51 the concave mirror R5 acts as the third reflection surface and the concave mirror R7 as the last reflection surface of the optical element 51 as a first reflection surface group 57 constructed on the three reflection surfaces are arranged adjacent to each other.
The convex mirror R4 as the second reflection surface of the optical element 51 and the convex mirror R6 as the fourth reflection surface, that of the first reflection surface group 57 Opposite, form a second reflection surface group 58 that integrates two reflective surfaces. The first and the second reflection surface group 57 and 58 form the optical element 51 , In this way, by using the reflecting surface groups integrating adjacent reflecting surfaces at decentered positions, the assembling time can be shortened, moreover, layout errors in assembling can be reduced as compared with the individual reflecting surfaces to be placed at predetermined decentered positions.
If the reflection surfaces each reflection surface group can be produced with the help of a metal mold integrated, can be a high position accuracy as well as a surface accuracy the individual reflection surfaces independently from the production quantities guarantee, and one reaches on simple Way, a high positional accuracy of the reflection mirror, the in the conventional System is difficult to achieve.
In addition, when zooming or focusing takes place using the optical element of this embodiment, a holding part for fixing the optical element to a movable stage directly on the optical element 51 be formed to a movement of the optical element to reach the moving stage.
20 shows an example of a holding part attached to the optical element 51 is trained.
To 20 is a holding part 59 at the rear of an effective reflection surface of the concave mirror R5 of the first reflection surface group 57 designed such that its bottom surface 59a extending in a direction parallel to a plane that is the reference axis 55 contains. Zooming and focusing is done by coupling the holding part 59 on a movable stage (not shown) and moving this movable stage.
Since the the reference axis 55 containing plane parallel to the bottom surface 59a of the holding part 59 runs, can be guaranteed in a simple manner, the parallelism between the movable stage and the optical element in that one of the holding part 59 and the movable stage coupled in parallel. For this reason, the influences of the decentering and the like of the reference axis, which may occur in the movement of the optical element, can be eliminated, and thus a deterioration of the optical performance is avoided.
Note that the floor area 59a of the holding part 59 preferably has a mirror surface. In addition, the surface roughness of the bottom surface is 59a preferably 0.08 μm or less (Rmax). When the floor area 59a polished to a surface roughness of about 1 to 2 μm (Rmax), tip areas of the three-dimensional surface can be destroyed or shaved off, parallelism with the reference axis 55 endangerment of the level of decentralization, so that the problem of decentralization arises again.
When another example of zooming or focusing using the optical element of this embodiment can be made use of a method in which holes on be formed with the optical element, wherein a shaft in the holes is fitted and moves the optical element along the shaft becomes.
21 shows an example in which a through hole 61 which is a shaft 60 at the first and second reflecting surface groups 57 and 58 is trained.
To 21 is the hole 61 in the first and second reflection surface groups 57 and 58 formed at locations the same distances from the the reference axis 55 and are separated from the effective light beam area of each reflection surface.
After inserting the shaft 60 in this hole 61 remains the shaft 60 parallel to the plane that the reference axis 55 and may act as a guide in the movement of the optical element to translate the optical element.
In 21 is just a shaft 60 present, but it can be used several shafts.
As That is, by forming a reflective optical element Using a metal mold, the element has multiple functions fulfill, for example, a hold function, a light shielding function and like, the number of parts as well as the manufacturing cost can be reduced and the features and performance of the optical element can be improved.
The following is based on the 22 the seventh embodiment explained. In this embodiment, another reflection surface group, which does not oppose the first and second reflection surface groups of the sixth embodiment, is added to change the directions of the reference light beam included in the optical element 70 enters and leaves this.
Referring to 22 is a third reflection surface group 62 formed by a concave mirror R10 on the side of the convex mirror R5 of the second reflection surface group 58 , The third reflection surface group 62 is the first and the second reflection surface group 57 and 58 not opposite and has a slope of about 45 ° with respect to the incident reference axis, about a reference axis 5a which, in the sixth embodiment, enters from the + Z axis direction to make it a reference axis entering from the + X axis direction.
On the other hand, a fourth reflection surface group 63 formed by a convex mirror R11 placed near the convex mirror R6 of the second reflection surface group 58 , The fourth reflection surface group 63 is the first and the second reflection surface group 57 and 58 not opposite and has a slope of about 45 ° with respect to the incident reference axis, about a reference axis 55b which, in the sixth embodiment, goes off in the direction of the -Z axis, making it to an axis which extends in the direction of the + X axis.
There in this embodiment the optical system formed by exclusively reflective surfaces is, unlike a conventional one System in which reflective surfaces in a refractive lens system added are to change the angle of the light rays can be in easier Way to add the third and the fourth reflection surface group, the not facing the first and second reflection surface groups. The added Reflection surface groups can the entrance and exit directions of a light beam change simultaneous correction of aberrations of the optical element.
at this embodiment can the reflection surface groups, which are adjacent to the first and second reflection surface groups, simultaneously with the formation of the first and the second reflection surface group getting produced.
There for example, the third reflection surface group of the second group adjacent, it can be made using the metal mold for the second Reflection surface group be formed.
By Add another reflection surface group, not the first and second reflection surface groups opposite, let the entry and exit directions of the reference axis light beam choose freely. In a camera, by the optical element of this embodiment Use, size and thickness can be the camera due to the free adjustment of the entrance and Reduce exit directions, thereby reducing the dead space to achieve and thus to create a camera with a form that so far was not available.
In 22 An entrance refracting surface R9 is disposed on the entrance side of the concave mirror R10, and has negative refractive power.
A Output refractive surface R12 is located on the exit side of the convex mirror R11 and has a positive refractive power.
At the Redirecting the optical path on the entrance side widens Generally, the effective light beam zone of each surface, because the distance from each area of the optical element inevitably becomes larger, so that the whole optical element a larger dimension receives.
Around to solve this problem, is in this embodiment an increase in the effective light beam zone of each surface due the deflection of the optical path thereby suppresses the concave mirror R10 and the entrance refractive surface R9 united to thereby reduce the size of the to reach the entire optical element.
By Redirecting the optical path on the exit side is also the Distance from the last level to the image plane inevitably decreased. By fusing the convex mirror R11 and the exit refracting surface R12 is in this embodiment a reduction in the rear focal length due to the deflection corrected the optical path.
As can be described in this embodiment by appropriate Placing the refractive elements and the reflective elements an embodiment can be achieved that the characteristics of each Uses elements. For example, the refractive elements divide the refractive power of the entire optical element, the reflection elements share the aberration correction. That way you can increase the degree of freedom in the optical design, and you can create a high performance optical element.
The first example of a metal mold structure for the preparation of the reflection surface groups discussed above will be described below with reference to FIGS 23 be explained.
23 is a sectional view of a metal mold 114 for the formation of the optical element 51 the sixth embodiment. The metal mold 114 is formed by a pair of metal mold units 115 and 116 for integrally forming the refracting surfaces R2 and R8, the concave mirror R3, the convex mirror R4, the concave mirror R5, the convex mirror R6 and the concave mirror R7 constituting the optical element 51 turn off.
Note that the metal mold unit 116 from three metal blocks 161 . 162 and 163 corresponding to the three reflection surfaces, namely the concave mirror R3, the concave mirror R5 and the concave mirror R7 of the first reflection surface group 57 correspond, is composed.
The metal mold unit 115 consists of four metal blocks 151 . 152 . 153 and 154 corresponding to the areas of the second reflection surface group 58 corresponding to the entrance refractive surface R2, the convex mirror R4 and the convex mirror R6 and the exit surface R8.
There in this embodiment the metal mold blocks several reflective surfaces correspond with curvatures, the reflection surface groups and refractive surfaces form, and these metal blocks As units are made, the metal molds are released even if individual reflective surfaces and refracting surfaces become located at decentered locations, allowing a one-piece fabrication the reflection surface groups and refractive surfaces possible is.
There made the corresponding metal surfaces corresponding to the individual reflection surfaces can be the machining edge needs to be opposite to the effective light beam zone, to be considered in the normal metal forming process is, not to be particularly intensively estimated, one can the Minimize the margin between adjacent reflective surfaces. It follows, that the size of the reflection surface group as a group of reflection surfaces can be minimized.
If however, a metal mold is divided into units of metal mold blocks is, must the positions of the separate metal mold blocks are precisely adjusted to a high position accuracy among the divided metal mold blocks too to reach. If every reflection surface is a stringent positional accuracy is preferably a metal mold with continuous surface used in which multiple reflective surfaces with curvatures by a single area are formed.
If however, the adjacent areas of the reflection surfaces of the Reflective surface blocks between can have a step, so can several reflective surfaces can not be formed by a single continuous surface.
The reason for this difficulty is explained below on the basis of 24 explained.
24 is a schematic view of the case that the metal mold unit 116 from a grinding wheel 117 is sanded.
at 24 Let's assume that the metal mold blocks 162 and 163 corresponding to the concave mirrors R5 and R7 between them contain a step. In general, the grinding wheel has 117 a spherical shape and grinds each reflection surface on the metal mold. Because the grinding wheel 117 has a spherical shape, it can not come into contact with an edge portion E of the metal mold blocks 162 and 163 is formed when the boundary area between the metal mold blocks 162 and 163 are processed according to the concave mirrors R5 and R7. For this reason, the edge region E can not be ground to form the adjacent reflection surfaces in the form of a single surface.
Around To avoid such situations, the neighboring ones Areas of the respective reflective surfaces are designed so that There are no steps between them. However, this is Method therefore not preferred because the adjacent ones Areas of the same curvature must have and consequently the degree of freedom in design becomes lower.
If in this embodiment the adjacent areas of the reflecting surfaces, the the reflection surface groups make out, have a step between them, the neighboring Areas outside formed and have the effective light beam zones of the reflection surfaces Forms that smoothly connect the reflection surfaces to be processed, so that several reflective surfaces be formed by a single continuous surface.
25 shows a second example of the metal mold structure of this embodiment. In this example, the concave mirrors R5 and R7 are the metal mold unit 116 through a neighboring area 118 smoothly connected to each other, without any step in the boundary area between them, so that the metal mold unit 116 is formed by a single continuous surface.
To 25 falls the neighboring area 118 from the effective zones of the concave mirrors R5 and R7, the shape is substantially freely adjustable as long as it does not obscure the effective zones of the reflecting surfaces.
As a method for determining the shape of the neighboring area 118 For example, if the shape of the neighboring area 118 is defined as smoothly connecting the edges of the effective zone of the concave mirrors R5 and R7, the metal mold unit 116 are formed by a single continuous surface without there being any edge areas extending from the grinding wheel 117 did not let it grind.
By smoothly connecting the adjacent reflection surfaces through areas outside of their effective zones thus forming the metal mold unit as a single continuous Area, which guarantees a high positional accuracy of each reflection surface becomes.
26 and 27 are sectional views in the event that the optical element 51 to 19 from the direction of the -Z axis and the ± Z axis, respectively. These sectional views also show the patterns of the effective light beam zones of the reflective surfaces.
26 is a sectional view in the event that the optical element 51 from the direction of the -Z axis. To 26 owns the optical element 51 a concave refracting surface R2 as an entrance surface, the concave mirror R4, the convex mirror R6 and the convex refracting surface R8 as the exit surface, which are disposed adjacent to each other.
27 is a sectional view in the event that the optical element 51 from the + Z axis direction. To 27 owns the optical element 51 the concave mirrors R3, R5 and R7 formed adjacent to each other.
Upon examination of the adjacent regions of the concave mirrors R3 and R5 in FIG 27 shows that the effective light beam zone of the concave mirror R3 trapezoidal shape, while the concave mirror R5 has a circular shape.
On the other hand, because the respective reflection surfaces of the optical element 51 structurally own rectangular shape, as seen from 27 As is apparent, when a reflection film is formed by deposition, sputtering, dipping and the like on the entire reflection surface, it must be formed in a wide zone outside the effective light beam zone.
If you go through the optical element 51 This is often the result of incident light from locations and angles that are different from locations and angles of the effective light rays. For this reason, light rays often hit areas outside the effective light beam zones.
If a reflection film is formed on the entire reflection surface is formed with high probability ghost light on a surface area outside the effective light beam zone, and preferably the zone, in which the reflection film is deposited, if possible reduced to avoid ghost light.
In this embodiment, a reflection film by deposition, sputtering, dipping and the like is only in the in 27 formed by the dashed line in a pattern which is similar to the shape of the effective light beam zone of each reflection surface, so that with respect to the effective light beam zone remains a predetermined edge, thereby avoiding that created by a zone outside the effective light beam zone ghost light.
There Furthermore on the entrance and exit refracting surfaces by deposition, Sputtering, dipping and the like formed an antireflection film is, lets Avoid the creation of ghost light on all surfaces that cause the optical Make element.
In addition, in this embodiment, a different zone than the film-carrying zones in 27 as a non-smooth surface, for example, designed as a diffusion surface. By simultaneously forming this diffusion surface when the reflection surface group is formed, when ghost light is generated by a surface area other than the effective light beam zone and impinges on a zone other than the film supporting zone, the amount of ghost light is reduced by the diffusion effect of the diffusion surface Intensity of ghost light lowers.
28 shows numeric data for a current design example.
As said, according to the invention in an optical element, which is formed by a first reflection surface block, in turn, formed by arranging a plurality of reflecting surfaces with curvatures at adjacent locations, and a second reflective surface block, the reflection surface block confronts and formed by arranging one or more reflecting surfaces with curvatures at adjacent locations, in the form of units because the first and second reflecting surface blocks are formed by a metal mold are formed, wherein the adjacent reflection surfaces of a optical prism with curvatures having reflective surfaces be prepared as units. Because also the reflection surface blocks through The metal mold can be made a relative decentering the respective reflection surfaces, the highest precision require, be avoided, so that the deterioration of the optical capacity is prevented.
Because Furthermore According to the invention a or several reflective surface blocks, the not facing the first and second reflecting surface blocks, can be located near the first and the second block, can be the directions of the optical rays entering the optical element enter and leave this, arbitrarily set. If an optical Element with refractive effect near the reflection surface block is arranged leaves the degree of freedom in aberration correction of the optical Elements, which in turn increase the imaging ability of the optical element improved. Furthermore let yourself according to the invention integrated forming a plurality of reflective surface blocks using a Metal form a high positional accuracy of the individual reflection surfaces in guarantee the optical element.
Because according to the invention elements are provided for coupling or unifying a plurality of reflection surface blocks such that they are located at predetermined positions of the individual reflecting surface blocks, and the optical element is configured to couple the plurality of reflective surface blocks or united, the fabrication of the respective reflective surface blocks is simplified, and the blocks can be exactly at predetermined locations with a predetermined Arrange spacing.
Because the elements for coupling or merging multiple reflective surface blocks in zones outside the Area of effective light beams are coupled or unified, can be prevented that the effective light rays hidden become.
Because Furthermore According to the invention, a holding part for fixing the optical element to an element is to be fixed to the optical element, or a hole for moving or fixing the optical element to another Area as the effective light beam zone of the reflection surface block is educated, leaves reduce the number of parts, and by moving the optical Elements caused by errors can be suppressed. Furthermore can be prevented that effective light rays in the optical Element to be covered.
There Furthermore According to the invention, a metal mold used to form the reflective surface blocks which is formed in the form of a metal forming unit, in turn divided into units of reflection surfaces is a metal mold unit, the adjacent reflecting surfaces through a single continuous surface represents, or a metal mold unit can be used, which several reflective surfaces and a neighboring area of the plurality of reflecting surfaces forms a single metal mold, so that the molding process independent of the form of the optical element can run off and the reflection surfaces with high accuracy can be formed. In addition, it can be a cheap optical Create element.
If Furthermore other areas than the zones for the effective light rays of the reflection surface block and the optical Elements with the refraction effect in the metal mold subjected to a Lichtabschirmprozess be, lets create an optical element, which is less of ghost light impaired is.
The invention is not limited to the above embodiments, but rather various Changes and modifications are possible within the scope of the invention. Therefore, reference is made to the appended claims for the scope of the invention.
A method of fabricating an optical element comprising a first reflecting surface block having a plurality of curved reflecting surfaces at adjacent locations and a second reflecting surface block facing the first reflecting surface block and having a curved reflecting surface or a plurality of curved reflecting surfaces at adjacent locations, characterized in that the first and second the second reflecting surface block are formed separately by a metal mold, and the optical element is formed by coupling or joining the first and second reflecting surface blocks.
The method of claim 1, wherein one or more Reflection surface blocks, the not facing the first and second reflecting surface blocks, can be arranged next to the first and second reflection surface block.
The method of claim 1, wherein an optical Limb with refractive effect next to the first reflection surface block and / or second reflective surface block is arranged.
The method of claim 2, wherein an optical A refractive effect member adjacent to the one or more reflective surface blocks not facing the first and second reflecting surface blocks, is arranged.
The method of claim 2, wherein the one or the plurality of reflective surface blocks that the first reflection surface block and / or not facing the second reflecting surface block, and the one or more reflective surface blocks and / or an optical one A refractive effect member corresponding to the first and second reflecting surface blocks not opposite, be formed integrally from a metal mold.
The method of claim 2, wherein the optical element is constructed by coupling or joining at least two blocks of the first reflection surface block, of the second reflection surface block and the one or more reflective surface blocks corresponding to the first and the second second reflection surface block not opposite.
The method of claim 1, wherein links are for coupling or joining the first and second reflecting surface blocks at the first and second Reflection surface block be formed.
The method of claim 6, wherein links are for coupling or joining the at least two blocks the first reflection surface block, of the second reflection surface block and the one or more reflective surface blocks corresponding to the first and the second second reflection surface block not opposite, on the at least two blocks from the first reflection surface block, second reflection surface block and the one or more reflective surface blocks corresponding to the first and the second second reflection surface block not opposite, be formed.
The method of claim 1, wherein the first and the second block together in places that are more effective outside one area Light beam of the optical element lie, coupled or joined together.
Method according to Claim 6, in which the first reflection surface block, the second reflection surface block and the one or more reflective surface blocks corresponding to the first and the first second reflection surface block not opposite, with each other in places outside a range of effective light beam of the optical element lying, coupled or joined together.
The method of claim 1, wherein, after the respective reflection surfaces of the first and second reflection blocks, a reflection film Precipitation, sputtering or immersion has been formed, which first and the second reflection surface block coupled together or put together become.
The method of claim 6, wherein, after on the respective reflection surfaces of the first Refle a reflection film has been formed by deposition, sputtering or dipping, the at least two blocks from the first reflecting surface block, second reflecting surface block and of the one or more reflection surface block, the second reflection surface block and the one or more reflection surface blocks, which are not opposed to the first and the second reflection surface block the plurality of reflecting surface blocks, which are not opposed to the first and the second reflection surface block, coupled or joined together.
The method of claim 1, wherein a holding part for fixing the optical element to a member on which the optical element is to be fixed, at the first or second reflection surface block is formed.
The method of claim 13, wherein the holding part is formed on a part that is different from an effective one Light beam part one of the first and second reflective surface blocks.
The method of claim 13, wherein at least one area of the holding part that touches the limb is a mirror surface.
A method according to claim 15, wherein the area of the Holding part that touches the limb, a mirror surface with a surface roughness Rmax of not more than 0.08 μm is.
The method of claim 1, wherein a hole for Moving or fixing the optical element in one of the first and the second reflecting surface block is formed.
The method of claim 17, wherein the hole is formed becomes parts different from the effective light beam parts the first and the second reflection surface block.
The method of claim 1, wherein the metal mold is formed by metal forming units, which are in units of reflecting surfaces of the are divided into first and second reflecting surface blocks, and the optical element is formed by the metal mold.
The method of claim 1, wherein the metal mold the adjacent reflection surfaces each of the first and second reflective surface blocks formed by a single, continuous surface, and the optical Element is formed by combining a metal mold and a another metal form.
The method of claim 1, wherein the metal mold is provided with the plurality of reflecting surfaces and, adjacent to these, with a neighbor part molded on a metal mold, and the optical element is formed by the metal mold.
The method of claim 1, wherein the metal mold in a part different from an effective beam part each of the first and second reflecting surface blocks, a light-shielding process is subjected.
The method of claim 1, wherein the metal mold at a part different from the effective light beam parts each of the first and second reflective surface blocks and the refraction-effect optical element, a light-shielding process is subjected.
The method of claim 1, wherein when the plurality Reflection surface groups placed at adjacent locations, an integrated mirror surface by joining mirror surface body groups according to claim 16 with adjacent reflecting surfaces, in a metal mold cavity is assembled inside the metal mold.
An optical element comprising a first reflective surface block with a plurality of curved reflecting surfaces adjacent locations and a second reflective surface block, the first reflection surface block opposite and one or more reflective surfaces at adjacent locations own, characterized in that the first and the second reflection surface block separated from each other and at least one of the blocks are integral a coupling or joining device comprising the first and second reflecting surface blocks to pair or join together.
The element of claim 25, wherein one or more reflective surface blocks not facing the first and second reflective surface blocks are adjacent to the first and second reflections surface block are arranged.
An element according to claim 26, wherein an optical A refracting member adjacent to the one or more reflective surface blocks not facing the first and second reflecting surface blocks, is arranged.
The element of claim 26, wherein the one or more the plurality of reflective surface blocks that the first reflection surface block and / or not facing the second reflecting surface block, and the one or more reflective surface blocks and / or an optical one Refractive member of the first and second reflecting surface blocks not opposite, are formed integrally by a metal mold.
An element according to claim 26, wherein the optical element is constructed by coupling or joining at least two blocks from first reflection surface block, second reflection surface block and of the one or more reflective surface blocks corresponding to the first and the second second reflection surface block not opposite.
An element according to claim 29, wherein links are for coupling or joining the at least two blocks from the first reflection surface block, the second reflection surface block and the one or more reflective surface blocks corresponding to the first and the second second reflection surface block not opposite, on the at least two blocks from the first reflection surface block, the second reflection surface block and the one or more reflective surface blocks corresponding to the first and the second second reflection surface block not opposite, are formed.
The element of claim 29, wherein the first reflective surface block, the second reflection surface block and the one or more reflective surface blocks corresponding to the first and the first second reflection surface block not opposite, coupled or joined together at such locations, the outside a range of effective light beam of the optical element lie.
An element according to claim 29, wherein, after being placed on the respective reflective surfaces the first reflection surface block, of the second reflection surface block and the one or more reflective surface blocks corresponding to the first and the second second reflection surface block not opposite, formed by deposition, sputtering or dipping a reflection film that was at least two blocks from the first reflection surface block, the second reflection surface block and the one or more reflective surface blocks corresponding to the first and the second second reflection surface block not opposite, coupled or joined together.
An element according to claim 25, wherein an optical Limb with refractive effect next to the first reflection surface block and / or the second reflection surface block is arranged.
An element according to claim 25, wherein links are for coupling or joining the first and second reflecting surface blocks at the first and second Reflection surface block are shaped.
The element of claim 25, wherein the first and the second block are coupled or joined together at locations, the outside a range of effective light beam of the optical element lie.
An element according to claim 29, wherein, after being placed on the respective reflective surfaces of the first and second reflection blocks, a reflection film Precipitation, sputtering or immersion has been formed, which first and the second reflection surface block coupled together or put together become.
An element according to claim 29, wherein a holding part for fixing the optical element to a member on which the optical element is to be fixed, at the first or second reflection surface block is formed.
An element according to claim 37, wherein the holding part is formed on a part that is different from an effective one Light beam part one of the first and second reflective surface blocks.
The element of claim 37, wherein at least one area of the holding part that touches the limb is a mirror surface.
An element according to claim 39, wherein the surface of the Holding part that touches the limb, a mirror surface with a surface roughness Rmax of not more than 0.08 μm is.
An element according to claim 25, wherein a hole for moving or fixing the optical element in one of first and second Reflection surface block is formed.
An element according to claim 41, wherein the hole is formed is at parts different from the effective light beam parts the first and the second reflection surface block.
DE1998639419 1997-12-02 1998-11-30 Optical element Expired - Lifetime DE69839419T2 (en)
JP32095098 1998-11-11
DE69839419D1 DE69839419D1 (en) 2008-06-12
DE69839419T2 true DE69839419T2 (en) 2009-09-10
DE1998639419 Expired - Lifetime DE69839419T2 (en) 1997-12-02 1998-11-30 Optical element
DE (1) DE69839419T2 (en)
JP3943952B2 (en) 2001-03-05 2007-07-11 キヤノン株式会社 Image reading device
JP4371634B2 (en) * 2002-07-11 2009-11-25 キヤノン株式会社 Imaging optical system and image reading apparatus using the same
DE102010040030B4 (en) 2010-08-31 2017-02-02 Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V. Lens and imaging system
CN103809278B (en) * 2012-11-06 2016-09-14 清华大学 Off-axis three-mirror
DE102015105673B4 (en) 2015-04-14 2018-03-08 Asphericon Gmbh Reflexive beam shaper
ZA7403309B (en) * 1974-05-22 1976-01-28 P Dolamore A reflective device
1998-11-11 JP JP32095098A patent/JPH11231115A/en not_active Withdrawn
1998-11-30 DE DE1998639419 patent/DE69839419T2/en not_active Expired - Lifetime
1998-11-30 EP EP19980122675 patent/EP0921427B1/en not_active Expired - Lifetime
1998-12-01 US US09/201,794 patent/US6616287B2/en not_active Expired - Lifetime
JPH11231115A (en) 1999-08-27
EP0921427A3 (en) 2004-08-04
EP0921427B1 (en) 2008-04-30
EP0921427A2 (en) 1999-06-09
US6616287B2 (en) 2003-09-09
DE69839419D1 (en) 2008-06-12
US20020041453A1 (en) 2002-04-11
EP0802436B1 (en) 2003-10-15 Small-sized variable magnification optical system
EP0788003B1 (en) 2003-12-10 Phototaking optical system and optical device