JPH1188606A - Film scanner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a film scanner in which the light emitted from a light source is used to a maximum. SOLUTION: This film scanner is provided with a mirror box 14 that receives a light emitted from a light source 12 and collects the light and emits the collected light. An incident port 14A of the mirror box 14 has an area and a shape that is capable of entirely containing all the contours of a cross section of luminous flux at the incident port 14A. On the other hand, an emission port 14B is formed, so as to emit a light-emitting an area including a detection area of an image frame recorded on a film. That is, the width Wout of the emission port 14B is formed wider than the width of the image frame. Furthermore, a length Lm of the mirror box 14 in the direction of an optical axis M is decided so as to satisfy predetermined conditions.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a film scanner, and more particularly, to a film scanner having a light transmitting means for irradiating a film with light so that light emitted from a light source efficiently reaches a reading means.

[0002]

2. Description of the Related Art Conventionally, there is a film scanner for digitally reading an image recorded on a film. This film scanner reads an image using an image sensor such as a CCD and stores the read image information as digital image data. That is, in the post-processing of image information reading (for example, printing on photographic paper by a printing machine), processing is performed based on digital image data read and stored by a film scanner. This makes it possible to configure the apparatus for performing the processing in the post-process separately from the film scanner.

[0003]

However, when an image recorded on a film is read by an image sensor such as a CCD in the above-described film scanner, it is necessary to uniformly irradiate the entire image frame area. .
For example, the light emitted from the light source is diffused using a diffusion tube to irradiate the entire image frame area. In this case, light is also emitted outside the image frame area, and there is a problem that light emitted from the light source cannot be used efficiently.

On the other hand, there is a film scanner which reads an image frame area using a line sensor or the like by dividing the image frame area for each scanning line (Japanese Patent Laid-Open No. Hei 7-271007;
No. 505083, No. 6-509694, No. 4
-500565). This film scanner has
A cavity for condensing light emitted from the light source and forming a line of light of uniform intensity is provided. Therefore, the light emitted from the light source is applied to a part (on the scanning line) of the image frame area recorded on the film. In other words, since light is prevented from being irradiated to the outside of the image frame area, light emitted from the light source can be used efficiently.

However, since the cavity provided in the above-described film scanner is formed in a cylindrical shape, there is a problem that the structure in the cavity becomes complicated. Further, in order to generate diffused light having uniform intensity in the cavity, a white reflective paint is applied to the inner wall (reflection surface) of the cavity. Therefore, the reflectance of light in the cavity is lower than that of the mirror, and the light collection efficiency is low. Further, to obtain diffused light, the number of times of reflection in the cavity may be increased, but the amount of light is attenuated with a decrease in reflectance, so that the efficiency is reduced.

In view of the above, it is an object of the present invention to provide a film scanner in which the structure of the light transmitting means is easy and the light emitted from the light source can be used to the maximum.

[0007]

According to a first aspect of the present invention, a light source for emitting light is provided.
Optical means for condensing the light emitted from the light source, an entrance having a predetermined opening area for receiving the light condensed by the optical means, and an exit having a smaller opening area than the entrance are formed. A light transmitting means having an inner peripheral surface as a reflective surface having a high reflectivity; and a reading means for receiving transmitted light emitted from the light transmitting means and transmitted through a detection area of the film, and reading an image recorded on the film. Means.

According to the first aspect of the present invention, the film scanner is provided with a light source for emitting light for irradiating a film loaded at a predetermined position, and an optical device for condensing the light emitted from the light source. Means are provided. In this optical means, light is collected using, for example, a reflector or a lens. Note that, for example, it is theoretically more advantageous to use a reflector to collect the light emitted from the light source than to collect the light emitted from the light source using a lens. That is,
In air, the lens is A. The reflector is N.I. A. > 1 is possible. In addition, N. A. = Sin θ (θ: angle of incidence on lens or reflector).

Further, the film scanner is provided with a light transmitting means. The light transmitting means is, for example, a cavity, and has an entrance having a predetermined opening area into which the light condensed by the optical means is incident, and an exit having a smaller opening area than the entrance. The inner peripheral surface of the light transmitting means is a reflective surface having a high reflectance. For example, a mirror or the like is used as the inner peripheral surface. Thereby, the reflectance of light in the light transmitting means can be increased.

Further, the film scanner is provided with reading means for reading an image recorded on the film.
As the reading means, for example, a linear image sensor or the like is used. That is, the reading means receives the transmitted light of the light applied to the film and reads the image on the film recorded in the area (detection area) where the light is applied.

According to a second aspect of the present invention, the light transmitting means is formed of a cylindrical body having a square cross section, and one pair of opposing reflecting surfaces are inclined in a direction approaching each other from the entrance to the exit. The other pair of opposing reflecting surfaces is characterized in that it has a wedge-shaped shape that is inclined in a direction away from each other from the entrance to the exit.

According to the second aspect of the present invention, the light transmitting means provided in the film scanner is formed by a cylindrical body having a square cross section. In this light transmitting means, one pair of opposing reflecting surfaces are inclined in a direction approaching each other from the entrance to the exit, and the other pair of opposing reflection surfaces are separated from each other from the entrance to the exit. It has an inclined wedge shape. As described above, by forming the light transmitting means in a wedge shape, it is possible to increase the light collection efficiency of the light incident on the light transmitting means.

According to a third aspect of the present invention, the area and the shape of the entrance formed in the light transmitting means are set in accordance with the area and the shape of the cross section of the optical path condensed by the optical means at the entrance. The area and shape of the exit are set according to the area and shape of the detection area of the film that irradiates the light incident on the light transmitting means.

As described above, the film scanner is provided with the light transmitting means having a wedge shape in a side view. According to the third aspect of the present invention, the area and the shape of the entrance formed in the light transmitting means are set in accordance with the area and the shape of the cross section of the optical path at the entrance of the light condensed by the optical means. That is, the entrance has an area and a shape that can accommodate all the contours of the optical path cross section at the entrance. On the other hand, the exit is set according to the area and shape of the detection area of the film that irradiates the light incident on the light transmitting means. For example, when the detection area is an area along the width direction of the image frame recorded on the film, the light is emitted so as to irradiate the area including the detection area. That is, the emission port is formed such that the dimension in the longitudinal direction is longer than the dimension in the width direction of the image frame recorded on the film.

Accordingly, substantially all of the light condensed by the optical means is incident on the light transmitting means, and the light incident on the light transmitting means is irradiated on the detection area of the film.
The light emitted from the light source can be used as close to the maximum as possible, and various characteristics of the scanner (shading, visual field of the imaging system) can be secured.

The invention according to a fourth aspect is characterized in that a diffusing plate is further provided at an exit formed in the light transmitting means.

According to the fourth aspect of the present invention, the diffuser is provided at the exit of the light transmitting means provided in the film scanner. This makes it easy to control the degree of diffusion of the light incident on the light transmitting means.
Therefore, it is possible to efficiently irradiate the light incident on the light transmitting means to the detection area of the film. In addition, it is possible to improve shading characteristics (reduce ripples and the like) and to make film scratches and the like less noticeable.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in FIGS.
The film scanner 10 according to the embodiment of the present invention includes:
A light source 12 is provided. This light source 12 is shown in FIG.
(A) As shown in FIG.
A and a reflector 12B for condensing light emitted from the light source lamp 12A. Note that the light condensing is not limited to converging, but includes collecting light emitted from the light source lamp 12A and reflecting the light on one side. Therefore, the light emitted from the light source 12 becomes a light flux 13 in a predetermined direction.

At the downstream side in the traveling direction of the light (light flux 13) emitted from the light source lamp 12A and collected by the reflector 12B, an infrared cut filter 22 and a shutter 24 are provided.
And a dimming filter 26 are arranged in this order. The infrared cut filter 22 and the shutter 24 thus arranged
The dimming filter 26 performs insertion into the light flux 13 based on predetermined conditions. This makes it possible to adjust the intensity of light applied to the film 16 via the mirror box 14 described below. By providing an ND filter (not shown) downstream of the light source 12, the intensity of light emitted from the light source 12 can be adjusted.

The mirror box 14 is provided downstream of the position where the dimming filter 26 is provided in the light traveling direction. Mirror box 14 in the present embodiment
Is configured by combining four plane mirrors such that the inner wall becomes a mirror. The details of the shape of the mirror box 14 and the conditions for determining the shape will be described later.

A film 16 is located downstream of the mirror box 14 in the light traveling direction. The film 16 is movable in a direction perpendicular to the optical axis M (see FIG. 3). This movement is performed by transport means (not shown).
The film 16 is transported in the direction of arrow R shown in FIG.

An image pickup lens 18 and a linear image sensor 20 are located downstream of the light transmitted through the film 16 in the traveling direction.
Are arranged in order. The imaging lens 18 is a film 1
6 is projected onto the linear image sensor 20. The linear image sensor 20 has a linear sensor area Q, and a signal (for example, light (eg, projection light from the imaging lens 18 in this embodiment)) corresponding to the color or light amount of incident light in the sensor area Q. , An analog signal or a digital signal). For example, the linear image sensor 20
Is C in which read pixels of a predetermined size are arranged in one line.
A CD sensor or a line sensor that outputs the signal according to one line of input light can be used.

The imaging lens 18 forms an image on the film 16 on the sensor area Q at a predetermined magnification by the projection. Therefore, the detection area T corresponding to the sensor area Q of the linear image sensor 20 can be set on the film 16 according to the predetermined magnification of the imaging lens 18 (see FIG. 2F).
Thereby, the linear image sensor 20 can read the image of the linear detection area T of the film 16 irradiated with the light.

Next, the shape of the mirror box 14 will be described. The opening on the light source 12 side of the mirror box 14 is an entrance 14A for collecting the light emitted from the light source 12. As shown in FIGS. 2C and 2D, the size S _M of the entrance 14A has an area and shape sufficient to accommodate all the light emitted from the light source 12, ie, the size of the light flux 13 at the entrance 14A. It is the contour of the cross section S _L match or area and shape including the same (however,
Except for diffuse reflection). As a result, substantially all of the light emitted from the light source 12 enters the mirror box 14.

On the other hand, the film 16 of the mirror box 14
The opening on the side is an emission port 14B for emitting the light that has entered the mirror box 14. The size T _M of the emission port 14B has an area and a shape capable of emitting light for irradiating a region including the detection region T on the film 16 as shown in FIGS. 2 (E) and 2 (F). In the present embodiment, the detection area T is the image frame 1 recorded on the film 16.
6A is a region along the width direction (see the arrow P shown in FIG. 1). Accordingly, the longitudinal dimension of the cross section _TL of the light beam 13 in the detection region T of the film 16, that is, the width dimension (W _out, described later) of the exit port 14B is the longitudinal dimension of the detection region T of the film 16 (image frame 16A). The injection port 14B is formed so as to be longer than the width dimension P).

Further, of the plane mirrors constituting the mirror box 14, one pair of opposed plane mirrors 14C
Are inclined so as to approach each other from the entrance 14A to the exit 14C. The other pair of opposed flat mirrors 14D are inclined so as to be separated from the entrance 14A to the exit 14C. That is, the mirror box 14 has a wedge shape. As described above, the entrance 14A and the exit 14B of the mirror box 14 are set to have a shape capable of sufficiently collecting the light from the light source 12 and a shape capable of sufficiently irradiating the detection region T.
That is, almost all light from the light source 12 is emitted from the mirror box 14 toward the detection region T. Thus, the light incident on the mirror box 14 can be collected and emitted. Further, by configuring the inner wall with a plane mirror so as to be a mirror, the reflectance of light incident on the mirror box 14 can be increased, and the light collection efficiency can be increased.

Further, the emission port 14 of the mirror box 14
B is provided with a diffusion plate 15. By disposing the diffusion plate 15, it is possible to easily control the degree of diffusion of the light emitted from the mirror box 14. Therefore, the light incident on the mirror box 14 is
6 can efficiently irradiate the detection region T.

Next, conditions for determining the shape of the mirror box 14, that is, conditions for optimizing the shape of the mirror box 14, will be described with reference to FIG. First, parameters used for the description are shown below.

N: the number of times light incident on the mirror box 14 is reflected φ ₀ ; the incident angle of light incident on the mirror box 14 φ _n ; the reflection angle when reflected n times by the mirror box 14 φ _out ; Emission angle L _n when light exits from L 14; distance in the longitudinal direction between n-th reflection point and n + 1-th reflection point in mirror box 14 L _m ; length of mirror box 14 in optical axis M direction β: Taper angle of mirror box 14 h _in ; Height of entrance of mirror box 14 h _out ; Height of exit of mirror box 14 W _in ; Width of entrance of mirror box 14 W _out ; Exit width

First, the entrance 14A of the mirror box 14
The condition regarding the size S _M (h _in × W _in ) will be described.
The size S _M of the entrance 14A depends on the light source 12 as described above.
Is sufficient area and shape, i.e. the contour of the cross section S _L of the light beam 13 at the entrance 14A with match or area and shape comprising the same to accommodate all the light emitted from.
By setting the size S _M of the entrance 14A Thus, substantially all the light emitted from the light source 12 is incident on the mirror box 14.

Further, the exit port 14B of the mirror box 14
Width W _out of, with the proviso that greater than the width P of the image frame 16A which has been recorded on the film 16 as described above. Thus, light can be applied to an area including the detection area T of the image frame 16A.

Furthermore, the length L _m of the mirror box 14 are defined as follows. In the present embodiment, of the light emitted from the light source lamp 12A, the reflector 1
A case will be described as an example where the shape of the mirror box 14 is optimized based only on the reflected light (optical path L) collected by 2B.

As shown in FIG. 3, the mirror box 1
4, the reflection angle φ _n when reflected n times is determined by the following equation (1), where β is the taper angle of the mirror box 14 (the angle between the mirror box 14 and the horizontal plane passing through the optical axis M).

Φ _n = φ _(n−1) −2 × β (1) (where n> 1) For example, the reflection angle φ ₁ when reflected once in the mirror box 14, that is, FIG. The reflection angle φ ₁ of light at the reflection point A shown in the following can be obtained by the following equation (2).

Φ ₁ = φ ₀ −2 × β (2) Here, as described above, φ ₀ is the angle of incidence when light enters the mirror box 14. For example, the angle of incidence φ ₀ of light on the mirror box 14 is 70 °, and the mirror box 1
4 is 10 °, the light reflection angle φ1 at the _first reflection point A can be obtained as 50 °.

Therefore, given the incident angle φ _{(n-1) of} arbitrary light incident on the mirror box 14 and the taper angle β of the mirror box 14, the reflection angle φ _n of light within the mirror box 14 Is determined.

The number of reflections n at which light incident on the mirror box 14 is reflected inside the mirror box 14 is obtained by the following equation (3). However, the condition that the light emitted from the mirror box 14 does not return (φ
_out > 0).

[0038]

(Equation 1)

For example, the angle of incidence φ ₀ of light on the mirror box 14 is 70 °, and the taper angle β of the mirror box 14 is 1
When the angle is 0 °, the number n of times of light reflection in the mirror box 14 can be determined to be three or less (n ≦ 3).

[0040] Then, determine the length L _m of the optical axis M direction of the mirror box 14. This can be obtained by calculating the length Ln between the reflection points of the incident light by the following expression (4) and adding the calculated _values . However, the length L _n between the optical axis M direction length L _m of the mirror box 14 is reflection point
If the value is longer than the value obtained by adding, the return light is generated in the mirror box 14 (see FIG. 4). Therefore, the length L _m in the optical axis M direction is determined so as to satisfy the condition of Expression (5).

[0041]

(Equation 2)

Therefore, the shape of the mirror box 13 provided on the film carrier 10 is determined so as to satisfy the condition shown in the above-mentioned equation. Mirror box 1 in this way
By optimizing the shape of 4, it is possible to increase the reflectance of the incident light and the light collection efficiency. That is, the light emitted from the light source 12 can be used to the maximum.

In the present embodiment, the case has been described where the shape of the mirror box 14 is optimized based only on the light reflected by the reflector 12B of the light source lamp 12A, but the present invention is not limited to this. For example,
The shape of the mirror box 14 may be optimized based on the direct light (the optical path N shown in FIG. 2) directly emitted from the light source lamp 12A and the reflected light from the reflector 12B. The method will be described below.

Since the conditions based on the reflected light of the reflector 12B are as described in the present embodiment, the relationships shown in the equations (3) and (5) are applied. The principle is the same for direct light. Accordingly, if the incident angle of light to the mirror box 14 is θ ₀ , the taper angle of the mirror box 14 is β, the number of times of reflection of light in the mirror box 14 is k, and the length of the mirror box 14 is L _s ,
The conditions of the following equations (6) and (7) are set.

[0045]

(Equation 3)

As described above, when optimizing the shape of the mirror box 14 based on the direct light emitted from the light source lamp 12A and the reflected light from the reflector 12B,
The shape is determined so as to satisfy the conditions of the expressions (3), (5), (6) and (7).

Further, the light source lamp 12A is
When the mirror box 14 is not covered with B, the shape of the mirror box 14 is determined so as to satisfy the relations of the equations (6) and (7).

Further, there is a case where the light emitted from the light source lamp 12A is condensed by using a lens or the like without using the reflector 12B. Such a case is the same as the case of optimizing based on only the reflector 12B of the light source lamp 12A as described in the present embodiment. Therefore, (3)
Mirror box 1 so as to satisfy the conditions of the equations (5) and (5).
Optimize the shape of 4. Although the light emitted from the light source lamp 12A may be collected using a lens, it is theoretically more advantageous to use the reflector 12B to collect the light emitted from the light source lamp 12A.

In the present embodiment, the light source lamp 12A is used, but the present invention can be applied to a case where a linear light source is used, so that the conditions of the above equations (3) and (5) are satisfied. The shape of the mirror box 14 may be determined.

As described above, by optimizing the shape of the mirror box 14 based on each condition,
The light emitted from the light source 12 in the film scanner 10 can be used to the maximum.

Since there are many sizes and types (such as densities) of the film 16, the mirror box 14 provided in the film scanner 10 is formed in advance in a shape corresponding to the size and type of the film, and the corresponding mirror box is provided. The box 14 may be replaced. Further, a mirror box that can change the shape while satisfying the above conditions may be formed and adjusted.

Further, in the present embodiment, the imaging lens 18
Although the case where the image recorded on the film 16 is projected on the linear image sensor 20 using the above is described, the invention is not limited to this. That is, it is sufficient that the image recorded on the film can be detected linearly. For example, the film image may be guided to the sensor by using a self-fox lens or the like. Alternatively, the image may be detected using a contact type sensor in which a self-fox lens is attached to the sensor.

Further, although the linear image sensor 20 is used in the present embodiment, the present invention is not limited to this. That is, any sensor that can read an image recorded on the film 16 may be used. This sensor may be of a density type or a three-color type, for example, a three-line color type. In the case of a three-color type, a dichroic mirror having a property of reflecting light of a desired color and transmitting all light of other colors may be provided before and after the arrangement position of the imaging lens 18. Alternatively, a photosensor array in which photosensors are arranged in a line may be used.

Further, in order to improve the shading in the mirror box 14, a diffusion plate may be inserted between the dimming filter 26 and the mirror box 14 shown in FIGS. Injection port 14
The diffusion degree of the diffusion plate 15 provided in B may have a spatial distribution.

In this embodiment, FIGS. 1 and 2
As shown in (A), the configuration is provided with the infrared cut filter 22 and the dimming filter 26, but is not limited to this. For example, an ultraviolet cut filter, a filter for spectral correction, and a filter for condition maintenance may be inserted.

Further, in the present embodiment, the intensity of the light emitted from the light source 12 is adjusted by using the dimming filter 26. However, the present invention is not limited to this. For example, the intensity of light may be changed by changing the aperture of the lens instead of the dimming filter 26, or an electronic shutter or the like may be provided on the sensor (linear image sensor 20) side to operate the electronic shutter. The intensity of light when an image is projected on the sensor may be adjusted.

In this embodiment, the mirror box 14 has been described as having a combination of flat mirrors. However, the present invention is not limited to the use of flat mirrors as long as the range is in accordance with the above equation. For example, a part or the whole may be constituted by a curved surface.

Although the film scanner 10 according to the present embodiment has been described using a transmissive film as the film, the present invention can be applied to a case where, for example, a reflective original is used.

[0059]

As described above, according to the present invention, light for irradiating an area including a detection area of a film and an entrance having a predetermined opening area and shape for receiving light emitted from a light source is emitted. Since the light transmitting means having the emission port and the inner peripheral surface being a reflection surface having a high reflectance is provided, it has an excellent effect that the light emitted from the light source can be used to the maximum.

[Brief description of the drawings]

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

2A is a side view of the film scanner, and FIG. 2B is a top view of the film scanner.
(C) and (D) show the state of the light beam at the entrance of the mirror box, and (E) and (F) show the state of the light beam emitted from the mirror box.

FIG. 3 is a main part configuration diagram showing a light source and a mirror box of the film scanner.

FIG. 4 is a schematic diagram showing a mirror box when return light is generated.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Film scanner 12 Light source (optical means) 14 Mirror box (light transmission means) 16 Film 30 Linear image sensor (reading means)

Claims (4)

[Claims] A light source for emitting light; an optical unit for condensing light emitted from the light source; an entrance having a predetermined opening area for receiving the light condensed by the optical unit; An emission port having an opening area smaller than the entrance port is formed, and an inner peripheral surface is a reflection surface having a high reflectance.The light transmission unit emits light transmitted from the light transmission unit and transmitted through a detection area of the film. Reading means for receiving light and reading an image recorded on the film. 2. The light transmitting means is formed of a cylindrical body having a rectangular cross section, and one pair of opposing reflecting surfaces are inclined in a direction approaching each other from the entrance to the exit, and the other pair of opposing reflections are provided. 2. The film scanner according to claim 1, wherein the surface is formed in a wedge shape inclined in a direction away from each other from the entrance to the exit. 3. An area and a shape of an entrance formed in the light transmitting means are set in accordance with an area and a shape of a cross section of an optical path condensed by the optical means at the entrance, and an area of an exit is provided. 3. The film scanner according to claim 2, wherein the shape and the shape are set in accordance with the area and the shape of the detection area of the film that irradiates the light incident on the light transmitting means. 4. The film scanner according to claim 1, wherein a diffusion plate is further provided at an emission port formed in the light transmission unit.