JPH0434517Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Field of Application] This invention relates to an image rotation device that is used in, for example, a microfilm reader and rotates an image of a document. More specifically, the present invention relates to an image rotation device in which an image rotation prism is rotatably mounted around the projection optical axis with its total reflection surface positioned parallel to the projection optical axis from the document.

[Conventional technology]

For example, in microfilm, each frame is not necessarily imprinted so that the upper and lower directions of the original image are all in the same direction. Therefore, when projecting the microimage on this microfilm, in order to always obtain an upright image, it is necessary to rotate the image so that the vertical direction of the original image aligns with the vertical direction of the screen, etc. be.

As one of the configurations for this purpose, an image rotation device using a prism for image rotation is known. A trapezoidal prism is mainly used as the prism for image rotation. This prism has the optical property of rotating the elephant by an angle twice the rotation angle by rotating around an axis parallel to its total reflection surface. That is,
The above-mentioned image rotation device utilizes the optical properties of a trapezoidal prism, etc.
The total reflection surface of this prism is positioned parallel to the projection optical axis from a micro image as a document, and the prism is rotatably mounted around this projection optical axis.

Conventionally, the prism for image rotation rotates around an axis perpendicular to its total reflection surface, and around an axis parallel to its total reflection surface and perpendicular to the optical axis projected from the original. was attached to a holder or the like that rotated around the projection optical axis without being allowed to rotate.

[Problem that the invention attempts to solve]

However, this prism for image rotation has errors during production, and there is a possibility that assembly errors may occur during assembly. Therefore, in order to reduce optical errors such as displacement of the elephant in an optical system that includes this prism, it is necessary to manufacture the prism itself for rotating the elephant or the holder to which it is attached with high precision, which increases costs. In addition, the work for assembling the prism for image rotation was time-consuming.

In particular, this prism for image rotation always changes the orientation of originals with different vertical directions to the same direction by rotating it around the projection optical axis from the original. Since it is desired to always form an image at the same position even when the optical component is fixed, even higher precision is required during manufacturing and installation than with optical components used in a fixed state.

In view of the above-mentioned circumstances, the purpose of this invention is to provide a mounting structure for a prism for image rotation that can be finely adjusted with a simple configuration.

[Means for solving problems]

The characteristic structure of the image rotation device according to this invention is that the prism for image rotation is held rotatably around a rotation axis perpendicular to the total reflection surface; The first fixing means for fixing the rotated prism and the first holding means are held via a spring member having spring properties that can swing in a plane direction parallel to the projection optical axis and perpendicular to the total reflection surface. a second holding means to oscillate the spring member by urging it from a direction opposite to the direction in which the spring member is restored;
A second fixing means for fixing the device at an arbitrary swing position is provided.

[Effect]

In other words, as a result of repeated experiments and studies, it has been found that the optical errors that occur in the above-mentioned optical system including the image rotation prism are based on the following factors.

That is, as shown in FIG. 5, a projection lens 3, a trapezoidal prism 4 which is a prism for rotating an image, and
Considering an optical system in which the screens 1 are arranged in that order, the chief ray L on the projection optical axis (hereinafter referred to as <x-axis>) C from the original (not shown) is:
After being reflected by the total reflection surface R of the trapezoidal prism 4, it reaches the screen 1. It is assumed that the trapezoidal prism 4 is designed so that the principal ray L' from the trapezoidal prism 4 to the screen 1 is on the <x-axis> if no optical error occurs.

Such an optical error in the optical system appears as a deviation of the principal ray L' toward the screen 1 with respect to the <x-axis>, that is, the projection optical axis C from the original. This shift can be considered by dividing it into components in the directions of two mutually orthogonal coordinate axes on a plane orthogonal to the projection optical axis C. That is, the components in the direction substantially perpendicular to the total reflection surface R of the trapezoidal prism 4 as shown in FIGS. This is a component in a direction substantially parallel to the total reflection surface R of the trapezoidal prism 4 and perpendicular to the projection optical axis C (hereinafter, the coordinate axis in this direction will be referred to as the <z-axis>) as shown in FIG.

First _, considering the <y-axis> direction, as shown in FIG. The principal ray L′ to screen 1 is
Parallel eccentricity δ _y1 and tilt eccentricity γ _y1 occur with respect to the <x-axis>. Furthermore, as shown in FIG. 6B, if the trapezoidal prism 4 is installed offset parallel to the
A parallel eccentricity δ _yz occurs in L′. Furthermore, as shown in FIG. , a parallel eccentricity δ _y3 and a tilt eccentricity γ _y2 occur.

On the other hand _, considering the <z-axis> direction, as shown in FIG. The chief ray L' toward the screen 1 has a parallel eccentricity δ _z1 with respect to the <x-axis>. In addition, as shown in FIG. 7B, due to manufacturing errors, the direction vector (ni→) of the incident plane of the trapezoidal prism 4 or the direction vector (no→) of the exit plane may deviate from the <x-y plane>. If it is tilted, the principal ray L' toward the screen 1 has a parallel eccentricity δ _y2 and a tilt eccentricity γ _z1 .

In other words, the optical errors include the parallel eccentricity δ _y and the tilt eccentricity γ _y with respect to the <y-axis>, that is, the coordinate axis perpendicular to the total reflection surface R of the trapezoidal prism 4, and <
x axis>, that is, the parallel eccentricity δ _y and the tilt eccentricity γ _y with respect to the coordinate axis parallel to the total reflection surface R of the trapezoidal prism 4 and perpendicular to the projection optical axis C from the original. The configuration for adjusting these various optical errors by moving the trapezoidal prism 4 itself is to rotate the trapezoidal prism 4 with respect to both the <y-axis> and the <x-axis>. It is necessary to correct the tilt eccentricity by moving the trapezoidal prism 4 in parallel to the <x-axis> and to correct the parallel eccentricity.

By the way, since the distance between the prism 4 for image rotation and the screen 1 is generally relatively large, the influence of tilt and eccentricity with respect to any axis is large, and even if a small error occurs, the screen 1 This results in a large image shift. On the other hand, even if parallel eccentricity occurs in the direction of any of the coordinate axes, the shift of the image on the screen 1 can be easily corrected by rotating the prism 4 for image rotation around an axis perpendicular to the coordinate axes. It is possible to modify it.

Therefore, based on the above-mentioned understanding of the characteristics of optical errors, the prism for image rotation is rotated around the axis perpendicular to the total reflection surface, and around the optical axis parallel to the total reflection surface and projected from the original. By rotating the prism about an axis perpendicular to the prism, it is possible to effectively correct optical errors caused by manufacturing errors and installation errors of the trapezoidal prism, although the configuration is simple.

〔Example〕

Examples of this invention will be described below based on the drawings.

FIG. 3 is a schematic diagram of the optical system of a microfilm reader printer equipped with an image rotation device according to this invention. Since this optical system itself is well known, it will be briefly explained.

This microfilm reader printer has a reader mode that enlarges and projects a microimage I, which is an example of a document, imprinted on a microfilm F onto a screen 1, and an enlarged copy onto recording paper using an electrophotographic process. It is now possible to switch between different print modes.

In either mode, the microfilm F is irradiated by a light source 2 consisting of a halogen lamp. The projection light beam that has passed through the microimage I on the microfilm F is
After passing through a projection device P having a projection lens 3 and a prism 4 for image rotation, the light is reflected by a first mirror 5a.

In the reader mode, this reflected projection light beam reaches the screen 1 after being reflected by the second mirror 5b and the third mirror 5c. Thereby, the micro image I is enlarged and projected onto the screen 1. Furthermore, in the print mode, the second mirror 5b is rotated and retracted to the position shown by the imaginary line in the figure. The projection light beam reflected by the first mirror 5a reaches the photosensitive drum 6 after being reflected by the fourth mirror 5d and the fifth mirror 5e.
Then, as the first mirror 5a and the fourth mirror 5d move rightward in the figure, an electrostatic latent image of the microimage I is formed on the photoreceptor drum 6. Then, by a well-known electrophotographic process,
An enlarged copy of the microimage I is provided on recording paper (not shown).

The image rotation prism 4 is a trapezoidal prism, and is configured to rotate around the projection optical axis C after passing through the microfilm F.

In other words, the vertical direction of the original image imprinted on the microfilm F does not always match the vertical direction of the screen 1, and on the other hand, the longitudinal direction of the microimage I does not necessarily match the longitudinal direction of the recording paper. . Therefore, in order to prevent the inconvenience that the image projected on the screen 1 in the reader mode is turned sideways, or that the necessary image protrudes from the recording paper in the print mode, the optical property of the trapezoidal prism is The projected image can be rotated by rotating the image rotation prism 4 by taking advantage of the fact that the projected image rotates around the same axis by an angle that is twice the rotation angle around the vertical axis. I have made it possible.

Next, the projection device P, which is an example of the image rotation device according to this invention, will be further explained.

As shown in FIGS. 1 and 2, this projection device P consists of a projection lens 3, a prism 4 for rotating an image, and a holder 7 that holds them. A gear portion 7a is integrally connected to the outer periphery of the holder 7, and this gear portion 7a meshes with the prism rotation gear 8. By operating an image rotation knob (not shown) linked to this prism rotation gear 8, the image rotation prism 4 can be rotated around the projection optical axis C from the micro image I. It is configured so that it can be done.
That is, the image can be rotated in the reader mode and print mode described above by operating the image rotation knob.

The projection lens 3 is attached to the small diameter portion 7c of the holder 7 with its end surface 3a in contact with the regulating portion 7b of the holder 7.
It is held internally and fixed with a set screw 9. In addition, the prism 4 for image rotation is a prism 4
prism adjustment plate 10 and holder 7 fixed to
It is attached to the holder 7 via a prism fixing plate 11 fixed to the holder 7.

As shown in FIGS. 4A and 4B, the prism adjustment plate 10 is formed from a flat plate, and has a pair of bent parts 10a at one end edge in the longitudinal direction, and a pair of protruding parts 10b on both sides. have. The image rotation prism 4 is in a state in which one end edge 4a is in contact with the bent portion 10a of the prism adjustment plate 10.
The total reflection surface R side thereof is bonded to the flat plate portion 10c of the prism adjustment plate 10. Furthermore, a pin 10d is caulked to a surface of the prism adjustment plate 10 that is different from the side to which the prism 4 is bonded.

Further, the prism fixing plate 11 is made of a leaf spring,
A flat plate portion 11b having an engagement hole 11a for the pin 10d of the prism adjustment plate 10, the prism adjustment plate 10
It consists of a pair of connecting parts 11c provided at positions corresponding to the pair of projecting parts 10b, a fixing part 11d for the holder 7, and the like. Then, the pin 10d of the prism adjustment plate 10 is connected to the prism fixing plate 11a.
The pair of screws 12 are inserted into the notches 11e formed in each of the pair of connecting portions 11c of the prism fixing plate 11 while being engaged with the engaging holes 11 of the prism adjusting plate 10. The prism adjustment plate 10 and the prism fixing plate 11 are temporarily fixed by screwing into the screw holes 10e formed in each of the prism adjustment plates 10 and 11, respectively.

In this state, the prism adjustment plate 10 and the prism fixing plate 11 are connected to the pins 10 of the prism adjustment plate 10.
It is in a state where relative rotation is possible around d. Then, as shown in FIG. 1, the prism fixing plate 11
With the prism adjustment plate 1 fixed to the holder 7,
By rotating the prism 4 around the pin 10d, the prism 4 for image rotation can be rotated around the axis ay perpendicular to the total reflection surface R thereof.

That is, on the screen 1, the prism adjustment plate 1
0 and the prism fixing plate 11 can be adjusted. After adjustment, the prism adjustment plate 10 and the prism fixing plate 11 are attached with screws 12.
It is fixed by fully tightening.

On the other hand, as shown in FIGS. 1 and 2, the prism fixing plate 11 is fixed to one end edge of the holder 7 by screws 13 at the end of its fixing portion 11d. The tip of the set screw 14, which is screwed into the screw hole 7d formed in the peripheral wall of the holder 7, is brought into contact with the flat plate portion 11b of the prism fixing plate 11.

That is, by rotating this set screw 14, the holder 7
By moving the prism fixing plate 11 in and out of the peripheral wall of the prism fixing plate 11 made of a plate spring, the prism fixing plate 11 is configured to elastically swing around the end of the fixing part 11d. Therefore, together with the prism adjusting plate 10 fixed to this prism fixing plate 11, the prism 4 for image rotation is
can be rotated around an axis az parallel to the total reflection surface R and perpendicular to the projection optical axis C from the microimage I.

In other words, on the screen 1, the prism fixing plate 1
The positional relationship with respect to the holder 7 can be adjusted. Note that 15 in the figure is a plate spring fixed to one end edge of the holder 7 for holding down the prism.

By configuring as above, it is possible to prevent errors in manufacturing the prism 4 holder 7 for elephant rotation, or
This makes it possible to reduce the occurrence of deviations in the image of the micro image I on the screen 1 due to errors in mounting the prism 4 and the holder 7.

That is, in this embodiment, the mounting structure between the prism adjusting plate 10 and the prism fixing plate 11 and the mounting structure of the prism fixing plate 11 to the holder 7 are such that the prism 4 for image rotation is perpendicular to its total reflection surface R. and around an axis a, which is parallel to the total reflection surface R thereof and perpendicular to the projection optical axis C from the micro-image I, which is the document, each supporting means is rotatably supported. It's HM.

Further, the screw 12 that is screwed into the screw hole 10e of the prism adjustment plate 10, the notch 11e of the prism fixing plate 11 through which the screw 12 is inserted, and the set screw 14 that comes into contact with the flat plate part 11 of the prism fixing plate 11,
There are separate adjustment mechanisms AM for rotating and fixing the prism 4 around the axes ay and az.

In the previous embodiment, the supporting means HM is an axis ay perpendicular to the total reflection surface R of the prism 4 for image rotation.
and around an axis az that is parallel to the total reflection surface R of the prism 4 and perpendicular to the projection optical axis C from the micro image I which is the original. explained. Instead of this, as the support means HM, these two axes can be used.
It may be something like a universal joint that allows rotation around ay and az at the same time.

Also, as an adjustment mechanism AM, instead of rotating and fixing the prism 4 for image rotation separately around both axes ay and az as explained in the previous embodiment, The prism 4 for image rotation around ay and az may be rotated and fixed at the same time.

[Effect of idea]

As described above, the image rotation device according to this invention rotates the prism for image rotation around an axis perpendicular to its total reflection surface, and parallel to the total reflection surface and perpendicular to the optical axis of projection from the original. Although it has a simple configuration, it is possible to effectively correct optical errors caused by manufacturing errors and installation errors of the trapezoidal prism by rotating it around the axis of the trapezoidal prism. From, the tolerance range when manufacturing prisms for image rotation such as trapezoidal prisms,
Also, the tolerance range during installation can now be both made larger than before. Therefore, the manufacturing cost of the image rotation prism can be reduced, and the work for assembling the image rotation prism can be performed relatively easily.

[Brief explanation of the drawing]

The drawings show an embodiment of the image rotation device according to the invention, in which FIG. 1 is a longitudinal sectional view of the image rotation device, FIG. 2 is a sectional view taken along the line -- in FIG. Schematic diagram of the system,
Figure 4 A and B are perspective views showing the mounting structure of the prism for image rotation, Figure 5 is a schematic diagram of the optical system including the prism for image rotation, and Figures 6 A to C and Figures 7 A and B are FIG. 2 is a schematic diagram showing errors in optical systems each including a prism for image rotation. 4...prism, R...total reflection surface, I...original, C...projection optical axis, ay, az...axis center, HM...
...support means, AM...adjustment mechanism.

Claims (1)

[Claims for Utility Model Registration] In an image rotation device equipped with an image rotation prism that has a total reflection surface and rotates and outputs a projected image by its own rotation, the prism is perpendicular to the total reflection surface. a first holding means for holding the prism rotatably around a rotation axis; a first fixing means for fixing the prism rotated by an arbitrary amount with respect to the first holding means; a second holding means that holds the spring member through a spring member that has spring properties that can swing in a plane direction that is parallel and perpendicular to the total reflection surface; and the spring member is attached from a direction opposite to the direction in which the spring member returns. An image rotation device comprising: a second fixing means for causing the image to swing at an arbitrary swing position and for fixing the image at an arbitrary swing position.