JPH0831946B2 - Micro film reader - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a microfilm reader capable of enlarging and projecting a microfilm on a screen and scanning a line sensor on the back of the screen to read a projected image. It is a thing.

(Technical background of the invention) A microfilm reader is widely known in which transmitted light of a microfilm is reflected by a plurality of mirrors and guided to a transmissive screen to form an enlarged image of the microfilm on the screen. In this case, since the screen is a transmissive type, external light such as electric light and sunlight penetrates the screen from the outside of the screen and enters the inside of the apparatus. When a part of this external light is reflected by the internal mirror and returns to the screen, there is a problem that the image on the screen becomes unclear.

In addition, when a projected image of this microfilm is read by a line sensor or the like and this image is stored in an optical disk device or output to a printer to obtain a hard copy,
When the external light transmitted through the screen is reflected by the mirror and is incident on the line sensor, there arises a problem that the quality of the read image is significantly deteriorated.

(Object of the Invention) The present invention has been made in view of such circumstances,
External light that has passed through the screen and entered the device does not return to the screen, improving the image quality of the screen, and the line sensor that reads the projected image on the back of this screen also receives the external light that has passed through this screen. It is an object of the present invention to provide a microfilm reader that prevents the external light from disturbing the image reading of the line sensor.

(Structure of the Invention) According to the present invention, an object of the present invention is to provide a microfilm reader that guides an enlarged projection image of a microfilm to a transmissive screen by a plurality of mirrors to form an image by scanning the projection image on the back surface of the screen. The screen is provided with a line sensor for reading, and the plane including the incident / emitted light of the final mirror immediately before the screen and the plane including the incident / emitted light of the mirror immediately before the final mirror are arranged non-parallel to each other, and the screen is This is achieved by a microfilm reader, characterized in that external light that passes through and enters the case of the device is reflected by the respective mirrors so as not to enter the line sensor.

(Embodiment) FIG. 1 is an overall view of an embodiment of the present invention, and FIG. 2 is an enlarged view of its optical system.

In these drawings, reference numeral 10 is a light source.
Light is transmitted through a condenser lens 12, a heat insulating glass 14, a cold mirror 16, a microfilm 18, a projection lens 20, an image inverting prism 22, mirrors 24 and 26, and a transmission type screen.
It is guided to 28 and an enlarged image of the microfilm 18 is formed on this screen 28.

A CCD line sensor 30 is arranged on the back surface of the screen 28 so as to be movable left and right, and a projected image can be read on the back surface of the screen 28 by scanning the line sensor. That is, the line sensor 30 is arranged long in the direction that traverses the screen 28 vertically, and the line sensor 30 performs main scanning by reading out an image in the length direction and sequentially outputting the image signal α as a time series signal, Sub-scanning is performed by moving the line sensor 28 in the left-right direction. The image signal α of the line sensor 30 is input to the CPU 34 via the input interface 32, where various processes are performed and the image signal is binarized. This binarized image signal β is output to the printer via the output interface 36.
Output to 38, where the image is printed out and a hard copy is obtained. The binarized signal β output from the CPU 34 can be recorded in an external storage device such as the optical disc device 40. Therefore, the required image of the original may be read out from the optical disc device 40 and printed out by the printer 38 as needed. Reference numeral 42 is a memory of the CPU 34.

As shown in FIG. 1, the microfilm 18 is placed horizontally on a film stand 46 provided in the device case 44, and light is vertically transmitted through the film 18 upward. The light transmitted through this film 18 is inverted by the prism 22 and is mirrored.
It is incident on 24 from below. The emitted light reflected by the mirror 24 is the final mirror immediately before the mirror 26, that is, the screen 28.
It is incident almost horizontally on 26 and is reflected here on the screen 28
Be led to. Ie the mirror 24 in front of this final mirror 26
, The plane χ including the incident light a and the emitted light b is substantially vertical as shown by the imaginary line in FIG. Further, the plane y including the incident light b and the outgoing light c of the final mirror 26 is substantially horizontal. Therefore, the external light that has passed through the screen 28 and entered the device case 44 is reflected by the final mirror 26, and should be reflected by the mirror.
Even if it returns to 24, it does not return to the screen 28 because it is reflected downward by this mirror 24.

In this embodiment, the planes χ and y of the two mirrors 24 and 26 containing the incoming and outgoing lights are made substantially orthogonal to each other. However, according to the present invention, it is possible to prevent external light from returning to the screen 28 by making the planes χ and y non-parallel to each other and setting the angle formed by the planes χ and y to a certain value or more.
The angle formed by is to be specifically determined so that external light incident at any angle does not return to the screen 28 at all positions of the screen 28.

(Effect of the invention) As described above, the present invention arranges each mirror so that the plane including the incoming / outgoing light of the final mirror immediately before the screen is not parallel to the plane including the incoming / outgoing light of the mirror immediately before that. Therefore, even if the external light passing through the screen is reflected by the mirror, it does not return to the screen, and there is no possibility that the external light deteriorates the image quality. Further, when the image on the screen is read by the line sensor that scans the projected image on the back surface of the screen, the external light does not interfere.

[Brief description of drawings]

FIG. 1 is an overall view of an embodiment of the present invention, and FIG. 2 is an enlarged view of its optical system. 18 …… Micro film, 24 …… Mirror, 26 …… Final mirror, 28 …… Transmissive screen, a, b …… Incoming light, b, c…
… Emitted light, χ, y… Plane.

Claims (1)

[Claims] 1. A microfilm reader for guiding a magnified projection image of a microfilm onto a transmissive screen by a plurality of mirrors to form an image, comprising a line sensor for scanning and reading the projection image on the back surface of the screen, The plane containing the incoming / outgoing light of the last mirror immediately before and the plane containing the incoming / outgoing light of the mirror immediately before this final mirror are arranged non-parallel to each other, and pass through the screen to enter the case of the device. A microfilm reader, characterized in that light is prevented from being reflected by the respective mirrors and entering the line sensor.