JPH06324411A - Photographic printer - Google Patents

Abstract

PURPOSE:To provide-a photographic printer capable of precisely shading a negative image recorded on a photographic film on a photographic printing paper with high throughput. CONSTITUTION:A liquid crystal cell 15 is arranged between the photographic film 19 and a light source 10 and also in between 1st and 2nd condensing lenses 14a and 14b, and a scattered light shielding member 17 with a pin hole 17a formed on a focal position of the 2nd condensing lens 14b is arranged. Scattered components among the light transmitted through the liquid crystal cell 15 is shielded by the scattered light shielding member 17 and only non-scattered components are transmitted through the member 17, so that the light loss is not generated in the non-scattered components. A 3rd condensing lens 27 and a diffusion sheet 28 are arranged between the scattered light shielding member 17 and the photographic film 19, and the photographic film 19 is illuminated with the light transmitted through the diffusion sheet 28 and photosensitive material 24 is exposed by the light transmitted through the photographic film 19, so that the photosensitive material 24 is exposed by the satisfactory quantity of light, thus, the throughput is improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photographic printer which prints and exposes a recorded image on a photographic film onto a light-sensitive material, and in particular, enables accurate and easy light control for each small area for density and color correction. Can be related to photo printers.

[0002]

2. Description of the Related Art As an apparatus for printing and exposing a recorded image on a photographic film on a photosensitive material, for example, Japanese Patent Publication No. 52-20.
The device shown in Japanese Patent No. 853 is known. This device is configured to project illumination light onto an image recorded on photographic film, apply different voltages to liquid crystal arranged in the transmission path of the illumination light, and control the amount of light for forming an image on the photosensitive material. Has been done. Also, Japanese Patent Publication No. 64-10819 discloses a device for illuminating a recorded image on a photographic film,
A liquid crystal device in which liquid crystal elements are arranged in a matrix form is provided between the photographic film and the film, and the amount of transmitted light is changed by changing the electric signal applied to each liquid crystal element to correct the printing density when an image is formed on the photosensitive material. An apparatus configured to perform color correction, character burning, etc. is shown.

[0003]

However, the Japanese Patent Publication Sho 52
According to the photographic printing apparatus disclosed in Japanese Patent Laid-Open No. 20853, it is difficult to form a sufficiently high-contrast image on a photosensitive material due to a change caused by light scattering of liquid crystal arranged in a transmission light path of a photographic film. There is. In the device disclosed in Japanese Patent Publication No. 64-10819,
Since it is necessary to arrange polarizing plates on the front side and the rear side of the liquid crystal, the light reaching the image sensor provided between the photographic film and the photosensitive material is already a large amount of light when passing through the polarizing plate and the liquid crystal. Have lost.

In the above-mentioned device, when the light intensity of the illumination light is increased in order to compensate for the loss of light quantity, the light energy that cannot be transmitted by the polarizing plate is accumulated as heat,
There is also a drawback that the liquid crystal temperature rises and the transparency and hue change depending on the temperature characteristics of the liquid crystal. As described above, since a commercially available liquid crystal cell using a polarizing plate has a low light transmittance, it takes a long time to print an image recorded on a photographic film on a photosensitive material, and it is possible to obtain an accurate image with high throughput. Could not be baked. The purpose of the present invention is to
It is an object of the present invention to provide a photographic printer capable of printing an image recorded on a photographic film on a light-sensitive material accurately and with high throughput.

[0005]

The above object of the present invention is to provide a light source for illuminating the photographic film, and a light source for illuminating the photographic film in a photographic printer in which a recorded image on the photographic film is exposed by exposure on a photosensitive material. A first condenser lens provided between the first condenser lens for collimating the illumination light from the light source and a second condenser lens for converging the light collimated by the first condenser lens to a focal position; And between the second condenser lenses, and between the lattice-shaped transparent electrodes arranged in a matrix on the two opposite surfaces,
A liquid crystal cell holding a light-scattering liquid crystal compound whose alignment state changes in accordance with a drive signal given to the grid-shaped transparent electrode corresponding to correction information; and a second capacitor disposed between the liquid crystal cell and the photographic film. A scattered light blocking member arranged so that a pinhole is located at the focal point of the lens, and a diffuser plate that illuminates the photographic film by uniformly receiving and diffusing light transmitted through the pinhole of the scattered light blocking member, A projection lens for printing and exposing a recorded image on the photographic film on a photosensitive material, an image sensor for detecting a recorded image on the photographic film between the projection lens and the photographic film, and a photographic film detected by the image sensor From the density distribution of the recorded image above, determine the correction area of the recorded image and the exposure information related to the correction amount, and combine the liquid crystal compound in the area corresponding to this information. Is accomplished by a drive signal for controlling the alignment state photographic printer, characterized in that a control means for sending to the grid-like transparent electrodes.

The diameter of the pinhole formed in the scattered light blocking member of the present invention is 0.1 to 5 mm in normal use.
If it is smaller than this, an interference phenomenon appears in the parallel light passing therethrough, and the resolution deteriorates. On the other hand, if it is larger than this, scattered light components are mixed in the irradiation light incident on the image on the photographic film, and a high-purity projected image of the image recorded on the photographic film cannot be formed on the photosensitive material.

In the photographic printer of the present invention, the liquid crystal compound that can be used for each liquid crystal element of the liquid crystal cell has its optical properties changed by changing the molecular alignment state of liquid crystal molecules to another molecular alignment state by applying an electric field. However, the one that causes the light scattering phenomenon is used. The liquid crystal compound used in the liquid crystal cell in the present invention is a polymer dispersion type liquid crystal, a dynamic scattering type liquid crystal, a phase transition type liquid crystal and the like.

First, the polymer dispersed liquid crystal will be described.
The polymer dispersed liquid crystal has a structure in which a nematic liquid crystal droplet is completely or partially surrounded by a polymer matrix.
Here, if the ordinary refractive index of the liquid crystal and the refractive index of the polymer are combined so that when the electric field is applied to the device, the liquid crystal is oriented in the direction of the electric field and the refractive indices of the liquid crystal and the polymer match. On the other hand, when the liquid crystal is transparent, when the electric field is not applied, the liquid crystal is randomly aligned due to the alignment regulating force from the polymer, so that the refractive index of the liquid crystal and the polymer do not match and light is scattered.

A liquid crystal cell using such a polymer-dispersed liquid crystal does not require a polarizing plate and can obtain a bright screen. Also,
It can be continuously molded in the form of a film, making it easy to make cells and increase the area. The polymer-dispersed liquid crystal has various names as described below depending on the dispersion form and the like, and these can be used in the present invention.

NCAP (Nematic Courvilinear Alligned)
Phase): The feature is that the liquid crystal is microencapsulated and put into a resin and hardened. Product name "UMU" (manufactured by Nippon Sheet Glass Co., Ltd.). (Japanese Patent Publication No. 3-52843, U.S. Patent Application No. 302,780, JL Fergason, 1985, SID Dig.
Tech. Papers 68p) PDLC (Polymer Dispersed Liquid Crystal): It is characterized by being formed by phase separation of liquid crystal and polymer.
(JW Doane et al., Appl, Phys. Lett., 48 (4), 269
(1986)) PNLC (Polymer Network Liquid Crystal): It is characterized in that the polymer matrix is an ultraviolet polymer compound and has a three-dimensional network structure. Developed by Dainippon Ink and Chemicals. (Takeuchi et al., 15th Liquid Crystal Conference 206 (1989))

Next, the dynamic scattering type liquid crystal will be described. For liquid crystal devices called Dynamic Scattering Modes (DSM), pages 195 to 230 of “Liquid Crystals Applications and Uses” (1990, World Scientific) edited by Vilendra Bahadur. It is described in the page and the references cited therein. The dynamic scattering type liquid crystal has a nematic liquid crystal sandwiched between a transparent electrode and two transparent substrates on which an alignment treatment is applied. The liquid crystal compound or composition enclosed therein usually has a negative dielectric constant anisotropy, has a rather low resistivity of about 10 ¹⁰ ohm centimeters or less, and has a conductivity anisotropy ( The difference obtained by subtracting the conductivity in the direction orthogonal to the conductivity in the long axis direction of the molecule) is positive. Further, usually, an ionic compound (hereinafter abbreviated as a dopant) is added at 10 to 1000 ppm.

Many known compounds exhibiting dynamic scattering action were known before 1980, for example, Schiff bases represented by N-p-methylbenzylidene-p-butylaniline and p-substituted phenyl. , P-substituted benzoic acid esters can be used. In addition to this, all nematic liquid crystals exhibiting dynamic scattering operation can be used.

Vertical alignment treatment and horizontal alignment treatment are known as alignment treatments for liquid crystal devices, and both of them are used for the dynamic scattering mode. Therefore, essentially any alignment treatment can be used in the present invention, as long as the light scattering of the cell in the non-lighted state is very small to meet the purpose of the present invention. Among them, the cell subjected to the vertical alignment treatment is advantageous over other alignment methods because of its high transmittance in the non-lighted state and good stereoscopic symmetry of light diffusion. As the orientation treatment method, for example, treatment with a silane coupling agent, treatment with a polymer such as polyimide, or the like can be used, and rubbing is preferably performed as necessary.

As the dopant, a quaternary organic ammonium salt such as tetrabutylammonium bromide is typically used. Here, carboxylate may be used as the counter anion. In addition, tetracyanoquinodimethane (T
A charge transfer complex represented by CNQ) and tetrathiafulvalene (TTF) can also be used.

Next, the phase transition mode will be described. A liquid crystal in a phase change (PC) mode undergoes a phase transition by applying an electric field, for example, from a cholesteric phase having a helical molecular arrangement to a nematic phase having a homeotropic molecular arrangement, or vice versa. When using a focal conic array cell of cholesteric liquid crystal,
The incident light when no electric field is applied is scattered by the focal conic array while passing through the cell, and the cell becomes cloudy. On the other hand, when an electric field exceeding the threshold value is applied, the helical structure of the cholesteric phase is dissolved and the nematic phase of the homeotropic arrangement is transformed, so that the cell looks transparent when no electric field is applied.

[0016]

According to the photographic printer of the present invention, the change in the degree of scattering of the liquid crystal compound in the small region held and divided between the grid-like transparent electrodes forming the liquid crystal cell is caused by the intensity of the transmitted light in each small region of the incident light flux. Appears as a change. For this reason, it is possible to control the density correction and the color correction for each small area on the photosensitive material on which the recorded image is printed and exposed. Since a scattered light blocking member is provided between the second condenser lens and the diffusion plate so that the pinhole is arranged at the focal position of the second condenser lens, when a drive signal is applied to the grid-shaped transparent electrode. When the scattering phenomenon occurs, the scattered component of the incident light is blocked, and only the non-scattered component hits the frame to be printed of the photographic film, and an accurate printed image can be obtained.

In addition, a pinhole for passing the non-scattered light component that has passed through the liquid crystal element is arranged behind the liquid crystal matrix, and the non-scattered light component that has passed through the pinhole is converted into a parallel light flux through a condenser lens to form a photographic film. The projection light projected on the photosensitive medium has an accurate negative image printed according to the shape and brightness of the negative image because of the incident light. Since the scattered light component that has passed through the liquid crystal cell does not enter the photographic film, the original image can be reproduced accurately, and the light of the non-scattered component reaches the light-sensitive material without loss, so printing exposure can be completed even if the exposure time is short. And the throughput is improved.

[0018]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic configuration diagram of a photographic printer according to an embodiment, in which light projected from a lamp 10 is reflected by a reflector 11 and passes through a diffuser plate 12, and then Y (yellow), M (magenta), C The light enters the light quality control unit 14 including the filters for each color of (cyan). The light quality adjusting unit 14 is controlled by the controller 18, and the amount of each filter inserted in the optical path can be changed.

Below the light quality control unit 14, the projection lens 1 is provided.
3 are arranged. Below the projection lens 13, the first
The liquid crystal cell 15 is disposed between the second condenser lens 14a and the second condenser lens 14b, and the light of the lamp 10 whose light quality is adjusted by the light quality adjusting unit 14 is applied to the liquid crystal cell 15 as parallel light by the condenser lens 14a. . The liquid crystal cell 15 is, for example, a polymer dispersed liquid crystal (PDLC) as a light-scattering liquid crystal.
Is held between opposed transparent electrodes, and a TFT type liquid crystal cell is provided with a TFT (Thin Film Transistor) in each pixel composed of a 30 × 20 simple matrix. The liquid crystal cell 15 has lattice-like transparent electrodes arranged in a matrix on each of two opposite surfaces, holds a scattering type liquid crystal between the electrodes, and has a function of scattering incident light by a voltage applied to the lattice-like transparent electrodes.

The collimated light transmitted through the liquid crystal cell 15 is focused by the second condenser lens 14b, passes through the pinhole 17a of the scattered light shield plate 17 arranged at the focal position of the condenser lens 14b, and is then reflected by the scattered light shield plate 17. The light is incident on a diffused illumination device 29 configured by a third condenser lens 27 and a diffuser plate 28 provided below. Here, the third condenser lens 27 may be omitted. Since the transmitted light of the liquid crystal cell 15 is focused by the condenser lens 14b and the photographic film 19 is illuminated by the light passing through the pinhole 17a, the scattered component of the light passing through the scattering portion generated by applying the voltage to the liquid crystal cell 15 is Only the non-scattered components on the optical axis that are blocked enter the photographic film 19. Therefore, it is possible to cause the light incident on the photographic film 19 to have an appropriate intensity difference for gradation and density correction.

The light transmitted through the liquid crystal cell 15 is focused by the condenser lens 14b and passes through the pinhole 17a, but the focus of the condenser lens 14b is the pinhole 17.
The light is set to the position a, and only the light of the non-scattering component is selected by the pinhole 17a and transmitted. Therefore, the light scattered by the liquid crystal cell 15 does not pass through the pinhole 17a, and the amount of light reaching the photographic film 19 decreases in the pixel region in the scattered state. In contrast,
The light passing through the transparent portion of the liquid crystal cell 15 receives the pinhole 1
Since it reaches the condenser lens 14b through 7a, there is no reduction in the amount of light. Therefore, the ratio of the light passing through the scattering portion and the transparent portion of the liquid crystal cell 15 is larger than that in the case where the light is not selected by the pinhole 17a.

When the photographic film 19 has a negative image, good gradation may not be reproduced in the low density part by illuminating the whole with light of uniform intensity, but it corresponds to the low density part of the negative image. If the liquid crystal cell 15 is set in a scattering state to reduce the amount of transmitted light, the gradation on the printing paper 24 corresponding to the low density portion can be reproduced well. On the contrary, there are cases where good gradation cannot be reproduced in the high density portion, but in that case, if the liquid crystal cell 15 corresponding to the high density portion is made transparent to increase the amount of transmitted light, the high density portion can be handled. The gradation on the printing paper 24 can be reproduced well. Such gradation correction will be described later.

The photographic film 19 is a film carrier 20.
When set on the film carrier 20, the film carrier 20 detects the print target frame position and sets the print target frame at a position facing the printing paper 24. The transmitted light of the liquid crystal cell 15 is diffused by the diffusion plate 28 and illuminates the photographic film 19 supported by the film carrier 20. The image of the frame to be printed is imaged on the photographic paper 24 set at the printing position by the projection lens 21. A shutter 22 is arranged between the projection lens 21 and the photographic printing paper 24, and the shutter 22 is opened and closed by a shutter drive unit 26.

An image sensor 33 is arranged diagonally below the film carrier 20. The image sensor 33 captures a negative image of the frame to be printed and sends this video signal to the monitor image processing unit 36. As is well known, the monitor image processing unit 36 performs A / D conversion, negative-positive conversion,
The monitor image that simulates the finished print is displayed on the color CRT 37 by performing the gradation correction, the saturation correction, and the like.
The saturation correction not only corrects the difference between the spectral sensitivity of the photographic printing paper 24 and the spectral sensitivity of the image sensor 33, but also performs color correction for displaying an image that simulates this correction when inputting correction data. The correction data is input by operating the keyboard 40 connected to the controller (control unit) 18, and the input density correction data and color correction data are displayed on the display 41 and displayed on the image processing unit 36. Sent.

Further, the image sensor 33 carries out three-color separated photometry for each point of the frame to be printed. This photometric signal is sent to the characteristic value calculator 45. The characteristic value calculation unit 45 uses the LATD
And various other characteristic values are calculated, and these are calculated as the exposure amount calculation unit 4
Send to 6. The exposure amount calculation unit 46 calculates the exposure amount for each color using a well-known exposure amount calculation formula, and sends this to the controller 18. In this exposure amount calculation, correction data input from the keyboard 40 is also used as needed.

The controller 18 converts the exposure amount for each color into an exposure time, and outputs a drive control signal to the liquid crystal driver 23 and the light quality adjusting unit 14 based on this. LCD driver 2
3 generates a drive signal for driving the liquid crystal cell 15 at a predetermined density by this drive control signal, and sets a predetermined pixel of the liquid crystal cell 15 to a predetermined light transmission amount. In addition, the light quality control unit 14 uses the drive control signal from the controller 18 for Y,
Insert the M and C filters into the optical path. Further, when the liquid crystal driver 23 is driven, the controller 18 opens the shutter 22 for a certain period of time via the shutter drive unit 26, and prints and exposes the image of the frame to be printed on the photographic film 19 onto the photographic paper 24. Note that the relationship between the exposure amount and the drive signal to the liquid crystal cell 15 is obtained in advance by experiments or the like, and the conversion table for this is stored in the memory in the controller 18.

When changing the gradation of the image to be exposed, the degree is detected by the photometric value of the image sensor 33, and the light transmittance of each corresponding pixel is set by a preset amount according to the degree. Change the tone. Image sensor 33
In the measurement of the image density distribution of the photographic film 19 by the method described above, in the case of a negative film, the density is considerably low in a portion where the image density is considerably low, and it may not be possible to express gradation if exposed as it is. For example, in a landscape photograph under natural sunlight, shaded areas are uniformly darkened, and it is difficult to reproduce good gradation.

As shown by the characteristic curve a of the negative film and the characteristic curve b of the photographic paper in FIG. 2, the range of density change D2 with respect to the range of change b of the exposure amount of the photographic paper is the exposure amount of a normal negative film (subject It is narrower than the density change range D1 with respect to the brightness change range a1. For this reason, when exposure is performed with light intensity such that the vicinity of the center of the photosensitive area of the printing paper and the vicinity of the center of the recorded image density of the photographic film match as in the conventional case
The previously selected portion a3 having a considerably high density (or the portion a2 having a very low density) is white (or black) on the photographic paper and the image is crushed and the gradation characteristic is lost.

When such an image on the photographic film 19 is detected by the image sensor, the photographic film 19
The liquid crystal driving signal is controlled so that the liquid crystal cell 15 corresponding to the portion a2 where the image density is considerably low has a low transmittance. Then, in FIG. 2, the negative density (exposure amount)
The exposure is performed under the same conditions as when E3 increased from E4 to E3. It was confirmed by the image sensor 33 that the amount of light applied to the photographic film 19 in this state sufficiently exhibited the gradation characteristics corresponding to the high image density portion on the photographic film 19. In this way, when the recorded image of the photographic film 19 is copied onto the photographic paper 24, the photographic film 19 is obtained.
The parts with low density were not crushed in black when
It was confirmed that good print exposure was possible.

Similarly, when the liquid crystal drive signal is controlled so that the transmittance is high even in the portion a3 where the image density is considerably high, the negative density (exposure amount) is E1 in FIG.
It was confirmed that exposure was performed under the same conditions as when the image density was decreased from E to E2, and the gradation characteristics could be sufficiently exhibited even for the portion a3 having a high image density. In the above embodiment, the image of the color negative film is exposed on the color photographic paper to form the image, but the present invention is also applicable to the case of exposing the image on the black and white photographic paper to form the image.

[0031]

As described above, the photographic printer of the present invention is a device for exposing the photographic film to illumination light and printing the transmitted light of the photographic film on a photosensitive medium through a projection lens. A drive signal corresponding to the correction area of the image is given to the element to change the scattering degree to correct the light intensity, and among the light passing through the liquid crystal cell, only the non-scattering component that is properly on the optical axis by the pinhole is displayed. By selectively passing the light and blocking the scattered light, the relative intensity ratio between the region where the light intensity is weakened by the scattered light and the region of the transmitted light is increased. That is, the light that has passed through the transparent portion of the liquid crystal cell passes through the pinhole with almost no loss, and if the liquid crystal cell scatters even a small amount of light, the scattered light hardly passes through the pinhole. The strength difference becomes extremely large.

Therefore, since it is possible to perform correction by exposing the photosensitive material with a high intensity light and by exposing a predetermined region with a low light amount, the correction exposure can be performed in a short time, and the throughput is improved. In addition, when dimming by the liquid crystal cell is not necessary, a sufficient amount of parallel light that has passed through the liquid crystal cell reaches the photosensitive material, so there is no loss of light quantity as in conventional liquid crystal cells, and the photosensitive material can be used in a short time. It can be exposed.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a photographic printer according to an embodiment of the present invention.

FIG. 2 is a characteristic diagram showing a relationship between a characteristic curve of a negative film and a characteristic curve of photographic paper.

[Explanation of symbols]

 10 Lamp 11 Reflector 12 Diffusion Plate 13 Projection Lens 14a First Condenser Lens 14b Second Condenser Lens 15 Liquid Crystal Cell 17 Scattered Light Blocking Plate 19 Photographic Film 20 Film Carrier 21 Projection Lens 22 Shutter 24 Photographic Paper 27 Third Condenser Lens 28 Diffuser

Claims (1)

[Claims] 1. A photographic printer in which a recorded image on a photographic film is printed on a photosensitive material by exposure, and a light source for illuminating the photographic film is provided between the light source and the photographic film. A first condenser lens for converting the light, a second condenser lens for focusing the light collimated by the first condenser lens to a focal position, and a second condenser lens arranged between the first and second condenser lenses,
A liquid crystal cell holding a light-scattering liquid crystal compound whose alignment state changes in accordance with a drive signal given to the lattice-shaped transparent electrodes corresponding to correction information, between the lattice-shaped transparent electrodes arranged in a matrix on two opposite surfaces; A scattered light blocking member arranged between the liquid crystal cell and the photographic film so that a pinhole is located at the focal point of the second condenser lens; and light received through the pinhole of the scattered light blocking member. A diffusing plate for uniformly diffusing and illuminating the photographic film; a projection lens for printing and exposing a recorded image on the photographic film on a photosensitive material; and a recording on the photographic film between the projection lens and the photographic film. An image sensor for detecting an image, and a correction area and a correction amount of the recorded image from the density distribution of the recorded image on the photographic film detected by the image sensor. Photographic printer determines the exposure information, characterized in that a driving signal for controlling the alignment state of the liquid crystal compound in the region corresponding to the information and control means for sending to the grid-like transparent electrodes.