JPH01245779A - Film image pickup device - Google Patents

Abstract

PURPOSE:To attain remarkable economy by inserting a transparent glass plate in an optical path between a filter and a dichroic mirror, making reference light beams of a flying-spot scanning light source into the transparent glass plate and making the reflected light beams incident into the dichroic mirror. CONSTITUTION:The transparent glass plate 41 is inserted to an optical path between a film 4 and a dichroic mirror 10 with a tilt of 45 deg. and a signal light S is transmitted with a low loss. On the other hand, reference light beams U reflected from a prism 20 is made incident on the transparent glass plate 41 through lenses 42, 43 sequentially as required at a right angle to the optical path of the signal light S. Almost 92% of the incident reference light beams U are transmitted through the transparent glass plate 41, and nearly 8% of its are reflected in a direction of a converging lens 9 and the optical system for the signal light S is used in common afterward. Thus, it is not required to use an ND filter and the 8% of reflected light beams are well balanced with the signal light S.

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to improvements in film imaging devices used in negative analyzers (also referred to as color analyzers) and the like.

``Conventional technology'' At a photo or movie film processing laboratory, positive photographs or positive films are created from negative films brought in by customers and then delivered. At that time, in order to reduce print loss, the negative is run through a negative analyzer before printing, and a positive image is displayed on the attached color monitor (also called a video monitor). The printing time for positive photographs and positive film is adjusted based on the data obtained from the changes in the position of the knob.

By adopting this method in the photo lab, it is possible to reduce the number of test prints.

Now, a flying spot cathode ray tube is normally used as the flying spot scanning light source of this negative analyzer (color analyzer). This cathode ray tube uses a phosphor with a short afterglow, and the light spot is scanned horizontally and vertically as a light source, similar to the cathode ray tube of a television. This light is focused by a lens and applied to a negative film, and the image information on the film is extracted as transmitted light. The light is efficiently collected and separated into the three primary colors of R, G, and H by a three-color separation optical system, that is, a dichroic mirror, and sent to a photomultiplier tube. There, the optical information is converted into a video signal, which then passes through appropriate processing circuitry to form a positive image on a color monitor.

A device that irradiates a film with the light from the flying spot scanning light source to obtain three-color light and inputs each light into a dedicated photomultiplier tube is called a film imaging device.

A conventional film imaging device will be explained with reference to the drawings.

As shown in FIG. 4, light emitted from the flying spot scanning light source 1 (referred to as scanning light, excluding the reference light described below) So
is reflected at a right angle by the prism 2 and is incident on the film 4 via the imaging lens 3. The light S (referred to as signal light) that has passed through the film 4 is incident on the reflecting mirror 7 via the condensing lens 6 and is reflected at right angles. It is incident. This incident light is decomposed by the same mirror 10 into three primary color lights, that is, red light SR, green light SG, and blue light SB, and each light is passed through a lens 11 to a photomultiplier tube 12.
is incident on the

The light (reference light 5) emitted from the beginning of each raster of the flying spot scanning light source 1 (horizontal scanning direction is indicated by a) is reflected at right angles by a prism 20, and is further reflected by a reflecting mirror 2.
1 and then enters the dichroic mirror 23 via the converging lens 22, and the trichromatic light UR; Uo;
Decomposed into UB, each light is reflected at a right angle by a reflecting mirror 24, passes through a convex lens 25, is reflected again by a reflecting mirror 26, and is reduced in light intensity by an ND (neutral, density) filter 27. Reference light U is film 4
photomultiplier tube 1)
2.

In each photomultiplier tube 12, the input signal light and reference light are photoelectrically converted and electrical signals (video signals) IR, IG, and IB are output, respectively.

One large mirror is commonly used as the dichroic mirrors 10 and 23, and is divided into two by inserting a shielding plate between them.

In the negative analyzer, as shown in FIG. 5, for example, the video signal IR output from the red photomultiplier tube 12 is amplified by the video amplifier 30 and supplied to the reference light separation circuit 31 (FIG. 6A). ). In the same circuit 31, a part of the electric signal (referred to as a reference optical signal) TJ' caused by the reference light is extracted by a separately applied gate pulse (Fig. 6B), and the level of the reference optical signal is adjusted by pulling and holding the electrical signal TJ'. A signal shown (referred to as a reference light level display signal 5) Lu (FIG. 6C) is applied to one input terminal of the comparator 32. Further, in the reference light decomposition circuit 31, the reference light signal U' is deleted from the output of the video amplifier 30 (FIG. 6A), and a red video signal is supplied to the color monitor 34.

In the comparator 32, the reference light level display signal Lu is set to the reference voltage E.
0, and a control signal corresponding to the difference in pressure between the two chambers is sent to the high pressure generation circuit (circuit that supplies high pressure to the photomultiplier tube 12) 35.
The reference light level display signal Lu is supplied to the reference voltage EO.
The output voltage of the high voltage generation circuit 35 is controlled so that it becomes equal to .

The photomultiplier tube 12 is very sensitive, and its gain can be easily changed by slightly changing the applied DC voltage (high voltage). On the other hand, if there is a slight fluctuation in the power supply, the level of the video signal fluctuates rapidly. Also, flying point scanning light source l
The level of the video signal supplied to the color monitor 34 fluctuates due to deterioration or dirt on the cathode ray tube, dirt on the optical system, fluctuations in the video amplifier 30, and the like. The feedback system using the above-mentioned reference optical signal is necessary to suppress the fluctuation.

Although the red feedback system has been described above as an example, the same applies to the green and blue feedback systems.

"Problem to be solved by the invention" In a conventional film imaging device, a dichroic mirror and its input/output optical system must be provided separately for the imaging system and the reference optical system, which requires a large number of parts. It has the disadvantage of being expensive and expensive.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned drawbacks and provide a more economical film imaging device.

``The kth means to solve the problem'' As mentioned in the conventional technology, in film imaging devices, light from a flying spot scanning light source is transmitted through a film, and the transmitted light is incident on a dichroic mirror to produce three-color light. In this invention, a transparent glass plate is inserted in the optical path between the film and the dichroic mirror, and the reference light from the reference light area of the flying spot scanning light source is incident on the transparent glass plate, The reflected light is incident on the dichroic mirror.

Embodiment An embodiment of the present invention is shown in FIG. 1, with the same reference numerals attached to parts corresponding to those in FIG. 4, and redundant explanation will be omitted. In this invention, a transparent glass plate 4 is arranged at an angle of 45 degrees in the optical path between the film 4 and the dichroic mirror 10, for example, in the optical path between the condensing lens 8 and the converging lens 9, so that the signal light S can be transmitted with low loss. Transmit. (The transmitted light corresponds to 92% of the incident light, resulting in a loss of only 0.8 dB.) On the other hand, the reference light U reflected from the prism 20 is transmitted through the lens 42 as necessary.
43 in order to make the signal light 5 enter the transparent glass plate 41 at right angles to the optical path of the signal light 5. The incident reference light U
92% of the rays pass through the transparent glass plate 41, but 80% of the rays pass through the transparent glass plate 41.
% is reflected in the direction of the converging lens 9, and thereafter the optical system for the signal light S is commonly used.

To explain in detail, as shown in FIG. 2, part of the signal light S or reference light U incident on the transparent glass plate 41 is reflected by the glass surface, and the remaining part is incident into the glass plate.

When the incident light that enters the glass plate is extracted from the glass medium into the air on the back side of the glass plate, part of it is reflected into the glass medium, and the remaining part is extracted into the air and becomes transmitted light. Become.

The light incident on the transparent glass plate 41 in this manner is reflected twice on the front and back surfaces thereof. The ratio of the amount of each reflected light to the incident light is D-(nl-n2)2 (1)
It is given by n1+nz. Here, nl is So1 in the refractive index of glass.
．． 5 and n2 is the refractive index of air and is 1, so D
= 0.04 (4%). That is, 4% of the incident light is reflected on the front and back surfaces of the glass, so a total of 8 parts are reflected and become reflected light, and the remaining 92 parts become transmitted light.

As is clear from the above description, 92% of the signal light S incident on the transparent glass plate 41 is transmitted and directed toward the dichroic mirror 10, while 8% of the reference light U is reflected and directed toward the dichroic mirror 10. I'll be heading there.

Although the signal light S suffers a loss of about 0.8 dB at the transparent glass plate 41, the loss is so small that it does not pose a problem.

Further, the reference light U directed toward the mirror 10 is 8% of the reference light U incident on the transparent glass plate 41, but since the reference light U does not pass through the film 4, the amount of light is large. It was attenuated by In the case of this invention, there is no need to use the ND filter 27,
The 8% reflected light is just the same as the signal light S (balance is maintained).

In addition, in FIG. 1, the flying spot scanning light source 1 is directed upward in the figure, and as shown in FIG. The reference light U reflected at a right angle is reflected at a right angle again at a reflecting mirror 44, and is then reflected at a right angle through a lens 32 etc. to a transparent glass plate 4.
It is also possible to make the light incident on 1.

"Effects of the Invention" According to the present invention, a transparent glass plate 41 is inserted in the optical path between the film 4 and the dichroic mirror 10, most of the signal light S is transmitted through the glass plate 41, and the reference light U is A portion of the light is reflected by the glass plate 41 in the direction of the dichroic mirror 10, and thereafter the signal light optical system is commonly used. Therefore, the conventionally used dichroic mirror 23 for reference light and the reflecting mirrors 24 and 26 required for each color.
, convex lens 25, ND filter 27, and many other parts can be reduced. On the other hand, since the transparent glass plate 41 and the like can be obtained at low cost, it is possible to significantly reduce the overall cost.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the film imaging device of the present invention, and FIGS. 2A and 2B show incident light and reflection when signal light or reference light is incident on the transparent glass plate 41 of FIG. 1, respectively. A diagram showing light and transmitted light; FIG. 3 is a block system diagram showing main parts of another embodiment of the present invention;
FIG. 4 is a block diagram of a conventional film imaging device, FIG. 5 is a block diagram of a control circuit for suppressing level fluctuations in a video signal using a reference light in a color analyzer, and FIG. It is a figure which shows the signal waveform of the principal part of a figure. Patent applicant Imagica Co., Ltd.

Claims (1)

[Claims] (1) In a film imaging device that transmits light from a flying spot scanning light source through a film, and enters the transmitted light into a dichroic mirror to separate it into three-color light, a transparent glass is used in the optical path between the film and the dichroic mirror. A film imaging device in which a plate is inserted, reference light from a reference light area of the flying spot scanning light source is incident on the transparent glass plate, and reflected light thereof is incident on the dichroic mirror.