JPS61173210A - Dimming device - Google Patents

Abstract

PURPOSE:To dim precisely and speedily the light of a light source by arranging one filter which has a rotating shaft at its end part at right angles to an optical axis and is formed in a simple shape in the optical path between a light source and a mixer for each component color. CONSTITUTION:A dimming device 18 and the mixer 20 are arranged in the optical path of exposure between the lamp 10 and a color film 14. The dimming device 18 is equipped with a cyan dimming part 22, a magenta dimming part 24, and a yellow dimming part 26 vertically at constant intervals. The cyan filter 28 of the cyan dimming part 22 is symmetrical about the rotating shaft and provided at a center part perpendicular to the optical path of exposure, so the constitution is simple, but it has effect making light passed through the mixer 20 homogeneous.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a light control device used in color printers, color photo enlargers, etc., for adjusting the color components of a light source.

[Conventional technology]

In conventional light control devices, a pair of filters are provided in the optical path between the light source and the mixer, and the filters are moved in a direction perpendicular to the optical path.

However, it is necessary to interlock the pair of filters using rollers, healds, cams, etc., and the mechanism is complicated. In addition, the filter had to have a special shape, which caused an increase in costs (Japanese Patent Laid-Open No. 52-6
f14]7ぢ, Special Publication No. 54-21092).

In addition, in a configuration in which one filter is simply moved in a direction perpendicular to the optical path, the amount of light transmitted through the filter is proportional to the amount of filter movement. 11 It becomes difficult to quickly move the filter according to the density, and furthermore, the accuracy varies significantly depending on the amount of movement of the filter, making it difficult to move the filter accurately as a whole.

[Problem that the invention seeks to solve]

SUMMARY OF THE INVENTION An object of the present invention is to obtain a light control device that has a simple configuration and is capable of controlling light quickly and accurately.

[Means for solving problems]

In the light control device according to the present invention, a filter having a rotation axis perpendicular to the optical axis at the end thereof is disposed in the optical path between the light source and the mixer.

[Effect]

A portion of the light from the light source passes through the filter. The light that has passed through the filter and the light that has not passed through the filter are mixed together through a mixer.
Color components are made uniform. By rotating the rotation axis, the amount of light passing through the filter changes, and the quality of light changes.

〔Example〕

Embodiments of a light control device according to the present invention will be described according to the drawings.

Figure 1 shows the main structure of a color printer.
An image on a color film 14 disposed between a lamp 10 and a lens 12 is formed on a roll of photographic paper 16 and exposed.

The lamp 10 is provided inside the concave mirror 17, and the light from the lamp 10 is radiated upward. A dimmer 18 and a mixer 2° are arranged in the exposure path between the lamp 10 and the color film 14. The light control device 18 includes a cyan light control section 22, a magenta light control section 24, and a yellow light control section 26 arranged at regular intervals in the vertical direction.
The cyan light control section 22, the magenta light control section 24, and the yellow light control section 26 have the same structure except for the color of the filter.

FIG. 2 shows the configuration of the cyan light control section 22, in which both ends of a rectangular cyan filter 28 are held between clamping pieces 30 and 32 each having a U-shaped end surface. Clamping piece 30.32
At the center of the side surface r1, rotating shafts 34 and 36 are provided protruding in mutually opposite directions. The rotating shafts 34 and 36 are respectively supported by a pair of opposing support plates 38 and 40. A rotating shaft of a flat pulse motor 42 is connected to the tip of the rotating shaft 34 passing through the support plate 38 .

Since the cyan filter 28 is symmetrical with respect to the rotation axis and is provided at the center in the direction orthogonal to the exposure paths, it is possible to prevent the light passing through the n-combiner 20 even though the cyan filter 28 has a negative n medium configuration. This has the effect of making the light quality uniform.

As shown in FIG. 1, a number 1 is placed around the lens 12. The light receiver 4.
4 is provided, and the amount of transmitted light of each component color of cyan, magenta, and yellow can be measured. Further, a shack 46 is provided between the lens 12 and the roll photographic paper 16.

Next, the operation of this embodiment configured as described above will be explained.

Cyan light control unit 22, magenta light control unit 24, A: [Angles θ1, θ2, θ formed between each filter of the low light control unit 26 and the optical axis]
3 (see Figure 1) to 0 degrees. The light receiver 44 measures the amount of cyan, magenta, and yellow light transmitted through the color film 4.

According to this measured quantity, the motor 4 is controlled by a control circuit (not shown).
2, cyan light control section 22, magenta light control section 24,
Rotation angles θ1, 2, θ of each filter of the yellow light control unit 26
Set 3 to an appropriate value. The light that passes through the filter and the light that does not pass through the filter from this θ are mixed through the mixer 20, and the light components become uniform and pass through the color film 14. When the shutter 46 is opened, the image on the color film 14 is created by the lens 12. The image is formed on the roll photographic paper 16 and exposed.

The light iT transmitted through the filter becomes I=Iosin θ. I here. is the amount of transmitted light at θ-π/2. Therefore, a simple shape can be selected for the change in ■, regardless of the shape of the filter. Also, the rate of change of ■ with respect to θ is
The larger the value of θ, the smaller it becomes, so the relationship is much closer to a logarithm than when simply moving the filter in the direction perpendicular to the exposure path, and it is only necessary to slightly correct the value of θ. Therefore, although it has a simple configuration, it is possible to adjust the light with almost the same accuracy regardless of the value of θ.In other words, it is possible to improve the overall dimming accuracy and to quickly control the rotation angle of the filter. It has the effect of being able to perform.

Note that a worm gear may be interposed between the rotating shaft 34 and the motor 42. Alternatively, the rotating shaft 34 may be manually rotated.

〔Effect of the invention〕

In the light control device according to the present invention, one simple-shaped filter for each component color is provided in the optical path between the light source and the confusion device, and the rotation axis is perpendicular to the optical axis at the end. This simple configuration has excellent effects in that the light source light can be dimmed accurately (and quickly).

[Brief explanation of drawings]

FIG. 1 is a schematic configuration diagram showing an embodiment in which a light control device according to the present invention is applied to a color printer, and FIG. 2 is a partial perspective view of the light control device. DESCRIPTION OF SYMBOLS 10... Lamp, 18... Dimmer, 20... Mixer, 22... Cyan dimmer, 27I... Magenta dimmer, 26... Yellow dimmer, 28. ... Cyan filter, 30.32... Holding piece, 34.3G... Rotating shaft.

Claims (1)

[Claims] A light control device characterized in that a filter having a rotation axis perpendicular to the optical axis at an end thereof is disposed in an optical path between a light source and a mixer.