JP2001013601A - Light quantity regulating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable a light quantity regulation device to finely regulate the light quantity of a light to be cast on a light source acting medium with a simple structure relating to an optical device, etc., using a digital micromirror device. SOLUTION: An automatic light control device 21, a color wheel 9, an integrator rod 24 and two condenser lenses 22 and 23 are arranged between an optical path between a light source lamp 8 and the digital micromirror device 10 in an exposure processing section of a digital printing device using the digital micromirror device 10. Respective light control filters 21a to 21c of the automatic light control device 21 are inserted into the optical path at prescribed insertion degrees, thereby, the incident light quantity on the digital micromirror device 10 is automatically regulated and eventually the exposure light quantity of photographic paper 7 (light source acting medium) is finely regulated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light amount adjusting device for an optical device, and more particularly, to a light amount adjusting device suitable for adjusting the light amount in an exposure device using a digital micromirror device.

[0002]

2. Description of the Related Art Light emitted from a light source lamp is made incident on a digital micromirror device (DMD) displaying an image, and reflected light of the digital micromirror device accompanied by the image (hereinafter referred to as "image light"). An optical device such as an exposure device, a light projector, a printing machine, or a copying machine, which irradiates a light source working medium (for example, photographic paper, a projection screen, etc.) with a light source working medium, has been conventionally known. Specifically, for example,
In the exposure apparatus, the printing paper (light source working medium) is exposed with the image light of the digital micromirror device, and the image displayed by the digital micromirror device is printed on the printing paper.

In such an exposure apparatus, since the photosensitive characteristics of the photographic paper differ depending on the type of the photographic paper, it is necessary to adjust the amount of exposure light according to the photosensitive characteristics of the photographic paper or other exposure conditions. . For this reason, in a conventional exposure apparatus using a digital micromirror apparatus, the light path between the light source lamp and the digital micromirror apparatus (on the optical axis) is usually determined according to the photosensitive characteristics of the photographic paper or other exposure conditions. By inserting a filter for reducing the amount of light, the amount of light incident on the digital micromirror device and, consequently, the amount of exposure of the photographic paper are adjusted.

[0004] Specifically, for example, a light amount reducing filter device provided with a plurality of light amount adjusting filters having different light transmittances (or light absorbances) is provided. The amount of light incident on the digital micromirror device is adjusted by inserting one light amount adjustment filter corresponding to other exposure conditions, or by inserting a combination of a plurality of light amount adjustment filters, so that the exposure light amount of the photographic paper is adjusted. To adjust.

[0005]

However, as described above, the light amount reducing filter device is arranged in the optical path between the light source lamp and the digital micromirror device to adjust the exposure light amount of the photographic paper. In a conventional exposure apparatus, when a large number of light quantity adjustment patterns are required, there is a problem that a correspondingly large number of light quantity adjustment filters must be prepared.

Further, a filter drive mechanism for holding a plurality (or a large number) of light amount adjusting filters, inserting these light amount adjusting filters alone or in combination into the optical path, or removing the same from the optical path is required. Therefore, there is a problem that the structure of the light amount lowering filter device and, consequently, the structure of the exposure device are complicated.

Furthermore, since the adjustment of the exposure light amount of the photographic paper can only be performed stepwise according to a relatively small number of light amount adjustment patterns prepared in advance, it is impossible to finely adjust the exposure light amount. There is.

[0008] Such light quantity adjustment is performed not only by an exposure apparatus using a digital micromirror apparatus, but also by other optical apparatuses using a digital micromirror apparatus, and furthermore, by using light emitted from a light source lamp as a light source. Various optical devices for irradiating the medium are also required. Therefore, these optical devices also have basically the same problem as the above-described exposure device.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional problems. Various optical devices, such as an optical device using a digital micromirror device, have been developed.
An object of the present invention is to provide a light amount adjusting device which has a simple structure and can finely adjust the light amount of light to be applied to a light source working medium.

[0010]

According to the present invention, there is provided a light amount adjusting device comprising: (a) a digital micromirror device for displaying light emitted from a light source lamp as an image; DMD) and irradiates (acts) the reflected light of the digital micromirror device with the image onto a light source working medium (for example, photographic paper, photosensitive material, projection screen, etc.). (Eg, exposure equipment, floodlight, printing machine, copy machine, etc.)
(B) a dimming filter (a plurality of, for example, three types of dimming filters of Y, M, and C) in an optical path between a light source lamp and a digital micromirror device.
And (c) operating a (predetermined) dimming filter of the automatic dimmer (gradual insertion into the optical path) so that the light enters the digital micromirror device. It is characterized in that the amount of light is adjusted.

The digital micromirror device is
A reflection type image display device comprising a plurality of micromirrors each capable of switching a reflection direction, and displaying an image by switching a reflection direction of each micromirror so as to correspond to an image. .

In this light amount adjusting device, the light adjusting filter of the automatic light adjusting device is arranged (inserted) at a predetermined position between the open position and the fully closed position, so that the light amount incident on the digital micromirror device can be reduced. Consequently, the amount of output light to the light source working medium can be automatically adjusted. Therefore,
There is no need to provide a light amount reduction filter device having a plurality or a large number of light amount adjustment filters, a filter driving mechanism, and the like, and the structure of the optical device is simplified. In addition, since the position of the dimming filter and, consequently, the amount of light incident on the digital micromirror device can be changed continuously (rather than in a staircase), a large number of light amount adjustment patterns can be easily set, and The output light quantity to the medium can be finely adjusted.

In the above light amount adjusting device, a light beam diffusing member (for example, a light beam diffusing member) having a light beam diffusing action is provided in the optical path (on the optical axis) closer to the digital micromirror device than the automatic light adjusting device.
It is preferable to provide an integrator rod). With this configuration, the amount of light in a cross section perpendicular to the optical axis, which is caused by the presence or absence of the light control filter (or the interruption of the light beam) in the light beam output from the light source lamp to the digital micromirror device side The unevenness is diffused or eliminated by the light beam diffusing member, and the light incident on the digital micromirror device is made uniform (uniform surface irradiation light is obtained).

In the above-mentioned light amount adjusting device, a plurality of (parallel) color filters (for example, R and R) are provided in the optical path closer to the digital micromirror device than the automatic light adjusting device.
After providing a color separation filter device including three types of monochromatic filters of G and B, a dimming filter (for example, Y, M, C)
Of the transmitted light of the three types of light control filters) (the width or wavelength range between the two long and short half-value wavelengths) of the transmitted light of the color filter corresponding to the light control filter in the color separation filter device. It is preferable that the width is set wider than the half-value wavelength width. The half value wavelength width of the transmitted light of the light control filter is set such that the shift of the half value wavelength width caused by the operation of the light control filter occurs in a wavelength region outside the half value wavelength width of the transmitted light of the color filter. More preferably,

With this configuration, the wavelength shift of the light control filter due to the operation mode of the light control filter (the degree of insertion into the optical path) does not affect the light output from the color filter. No color shift occurs in the light incident on the micromirror device.

Further, another light amount adjusting device according to the present invention comprises: (a) a light source lamp and a plurality of color filters (for example, a color filter for separating light emitted from the light source lamp).
(B) an optical path between the light source lamp and the color separation filter device, wherein the color separation filter device includes three types of monochromatic filters (R, G, and B). In the middle (on the optical axis), there is provided an automatic light control device including a light control filter (a plurality of, for example, three types of light control filters of Y, M, and C). By operating the dimming filter described above, the output light amount of the color separation filter device is adjusted.

In this light amount adjusting device, the light adjusting filter of the automatic light adjusting device is arranged (inserted) at a predetermined position between the open position and the fully closed position, so that the output light amount of the color separating filter device and, hence, the light source The output light quantity to the working medium can be automatically adjusted. Therefore, it is not necessary to provide a light amount reduction filter device including a plurality or a large number of light amount adjustment filters, a filter driving mechanism, and the like, and the structure of the optical device is simplified. In addition, since the position of the light control filter and, consequently, the output light amount of the color separation filter device can be continuously changed, a large number of light amount adjustment patterns can be easily set, and the output light amount to the light source working medium can be adjusted. Can be performed finely.

In the above-mentioned light quantity adjusting device, the half value wavelength width of transmitted light of the light control filter is set wider than the half value wavelength width of transmitted light of the color filter corresponding to the light control filter in the color separation filter device. Is preferred. The half value wavelength width of the transmitted light of the light control filter is set such that the shift of the half value wavelength width caused by the operation of the light control filter occurs in a wavelength region outside the half value wavelength width of the transmitted light of the color filter. More preferably,

With this configuration, the wavelength shift of the light control filter due to the operation mode of the light control filter (the degree of insertion into the optical path) does not affect the light output from the color filter. No color shift occurs in the output light of the color separation filter device.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be specifically described below. As shown in FIG. 1, a digital printing apparatus 1 including a light amount adjusting device according to the present invention is substantially an exposure processing section 2 (an exposure apparatus corresponding to an “optical apparatus” described in the claims). , A development processing unit 3 and a drying processing unit 4. Then, in the exposure processing section 2, the paper roller 6 in the paper magazine 5 is
Photographic paper 7 (light source working medium, photosensitive material)
But after being pulled out from the paper magazine 5, and is conveyed in the direction indicated by arrow A ₁ and arrow A ₂ by paper transport mechanism having a conveyance roller 13 and the like.

In the exposure processing section 2, the original light L radiated from the light source lamp 8 (for example, a halogen lamp)
₁ (white light) is a rotary color wheel 9 (corresponding to the “color separation filter device” described in the claims)
Through an R (red), G (green), or B (blue) color filter (not shown), thereby becoming an R, G, or B original light L ₁ (monochromatic light), and The integrator rod 24 (corresponding to the “light diffusing member” described in claims) and the first and second integrator rods will be described.
Irradiates the digital micromirror device 10 through the two condenser lenses 22 and 23 (see FIG. 3). In the optical path between the light source lamp 8 and the color wheel 9, an automatic dimmer 21 described later is provided.

Here, the color wheel 9 is continuously rotated in synchronization with the color filter switching timing in accordance with the speed of the exposure processing, so that the color filters to transmit light are sequentially switched. I have. That is, the color of the original light L _1, for each fixed time, switched repeated R, G, in the order of B. Instead of the continuous rotation as described above, the color wheel 9 may be intermittently rotated at regular time intervals in accordance with the speed of the exposure processing to sequentially switch the color filters through which light is transmitted.

The digital micromirror device 10
A reflected light, the image light L ₂ to the digital micromirror device 10 is accompanied by an image to be displayed, the printing lens 1
1, the image light L _{3 is obtained} (the image is stretched), and the image light L ₃ is irradiated on the photographic paper 7 and
Is subjected to an exposure process. Thus, the image displayed by the digital micromirror device 10 is
And the image is formed on the photographic paper 7, and the image is printed on the photographic paper 7. Such exposure processing (or printing processing) is performed repeatedly for the three monochromatic lights of R, G, and B. That is, the R, G, and B images are superimposed and printed on the same exposure area of the printing paper 7.

In the exposure processing section 2, as the exposure processing method, for example, while the photographic paper 7 is continuously moved by the photographic paper transport mechanism, a belt-like or line-like shape having a length in a direction perpendicular to the photographic paper transport direction is used. Scanning exposure (line exposure) for sequentially performing exposure processing for each exposure processing area is used. It is also possible to use surface exposure in which the photographic paper 7 is intermittently moved by the photographic paper transport mechanism, and the planar exposure processing area is exposed when the photographic paper movement is stopped.

The photographic paper 7 on which the image is printed after being subjected to the exposure processing is transferred from the exposure processing section 2 to the development processing section 3 by a photographic paper transport mechanism having transport rollers 13 and the like.
Transported to Then, the printing paper 7, while meandering developing unit developing solution tank 12 provided in the 3 to move generally in the arrow A ₃ direction is developed by the development processing solution. Thereafter, the printing paper 7 that has been developed is conveyed from the developing section 3 to the drying unit 4 by print paper transporting mechanism, it is dried while moving the drying unit 4 in the arrow A ₄ direction, digital printing device Retrieved from 1.

Hereinafter, the specific structure and function of the digital micromirror device 10 will be described. As shown in FIG. 2A, the digital micromirror device 10 has a plate-like outer shape having a substantially rectangular spreading surface, and has a substantially rectangular micromirror portion in a frame portion 14 forming a housing in plan view. 15 are arranged. And FIG.
As shown in FIG. 2B, a large number of micromirrors 16 (only six are shown in FIG. 2B) are provided.
(Image display elements) are arranged in a grid pattern. In plan view, each of the micromirrors 16, the horizontal direction to have no both generally 16μm dimension H ₁ of size D ₁ and the vertical direction (corresponding to the printing width direction) (corresponding to the paper transport direction) is approximately 17μm _They are arranged in a substantially square shape so that the horizontal interval D ₂ and the vertical interval H ₂ are both approximately 1 μm. In this digital micromirror device 10, 1280 micromirrors 16 are arranged in the horizontal direction (1280 pixels), and 1024 micromirrors 16 are arranged in the vertical direction (1024).
Pixel). In addition, each micro mirror 16 is 1
One pixel.

As shown in FIG. 2C, each micromirror 16 (16a, 16b) has a structure in which a mirror plate 17 is supported by a yoke 18 via a support column 19. Although not shown in detail, the yoke 18 is rotatably connected to the substrate 20 via a connection structure. Here, when a memory element (not shown) arranged on the substrate 20 below each yoke 18 is energized, the state is shown, for example, on the left-side micro mirror 16a in FIG. 2C. Thus, the yoke 18 is rotated and inclined by the electrostatic action of the memory element until the left end of the yoke 18 contacts the substrate 20. In this state, the normal line S ₁ of the mirror plate 17 is inclined leftward by a predetermined angle θ with respect to the vertical line S ₀ (+ θ). That is,
The reflecting surface (spreading surface) of the mirror plate 17 is tilted to the left by θ (hereinafter, this state of the micromirror is “on”).
). At this time, the reflected light from the micromirror 16a is incident (irradiated) on the printing lens 11 and thus on the printing paper 7.

On the other hand, when the memory element is not energized, for example, the micromirror 16b on the right side in FIG.
As shown in FIG. 2, the yoke 18 is rotated and inclined by the electrostatic action of the memory element until the right end thereof contacts the substrate 20. In this state, the normal S ₂ of the mirror plate 17 is inclined rightward by a predetermined angle θ with respect to the vertical line S ₀ (−θ). That is, the reflection surface of the mirror plate 17 is inclined rightward by θ (hereinafter, this state of the micromirror is referred to as “off”). At this time, the reflected light of the micromirror 16b is not incident (irradiated) on the printing lens 11 (the photographic paper 7), but is absorbed by a light absorbing plate (not shown).
Is absorbed by

Thus, the digital micromirror device 1
0 switches (sets) the on / off state of each micromirror 16 based on digital image data corresponding to an arbitrary image so as to correspond to the image. That is, the micromirror unit 15 of the digital micromirror device 10 displays an image in which each micromirror 16 has one pixel (one pixel). Here, the micromirrors 16 are turned on and off independently of each other, and the time required for switching on and off is about 10 microseconds.

Each micro mirror 16 is turned on for a time corresponding to the duty. That is, the duty here is the ratio of the time during which the micromirror 16 is turned on. Therefore, the higher the duty, the higher the density (print density) of the print (printed image), and the lower the duty, the lower the print density. The duty is 0 in principle.
It can be any value within the range of ~ 100%,
Usually, it is often used in the range of 25% or less.

In this way, the exposure processing section 2 uses a plurality of micromirrors 16 to form each dot (pixel) of the print, and uses the photographic paper 7 corresponding to the dot.
Are exposed, and the density gradation of the print is expressed by a combination of the number of micromirrors 16 used and the exposure time in the exposure by each micromirror 16.

Hereinafter, a specific configuration and functions of the exposure processing section 2 for constructing an exposure system from the light source lamp 8 to the photographic paper 7 via the digital micromirror device 10 and the like will be described. As shown in FIG. 3, in the exposure processing section 2, the original light L ₁ (white light) emitted from the light source lamp 8 is incident on the color wheel 9 via an automatic light control device 21 described later. The R, G or B original light L ₁ (monochromatic light) is obtained by the R, G or B color filter of the color wheel 9. The original light L ₁ (monochromatic light) is
4 and further enter the digital micromirror device 10 through the first condenser lens 22 and the second condenser lens 23. The integrator rod 24
Is an optical axis M ₂ made of glass or quartz.
An optical rod having a light-diffusion effect, having a substantially rectangular cross section taken along a plane perpendicular to the optical rod.

The digital micromirror device 10
The image light L ₂ accompanied by the image displayed by the digital micromirror device 10 becomes the image light L ₃ via the printing lens 11 (the image is elongated), and is applied to the photographic paper 7. . In FIG. 3, a straight line M ₁ represents the optical axis of the image light L ₂ and L ₃ , and a straight line M ₂ represents the optical axis of the original light L ₁ . Here, the optical axis M ₁ of the image light L ₂ or the image light L ₃ and the optical axis M ₂ of the original light L ₁ are defined by a predetermined angle α corresponding to the reflection characteristic of the digital micromirror device 10.
(For example, 20 °).

In the exposure processing section 2,
It is necessary to adjust the exposure light amount of the photographic paper 7 according to the photosensitive characteristics of the photographic paper 7 or other exposure conditions. Therefore, in the exposure processing unit 2, the amount of light incident on the digital micromirror device 10 is adjusted by an automatic light control device 21 provided in the optical path between the light source lamp 8 and the color wheel 9, and the photographic paper 7 is adjusted. Is adjusted.

The automatic light control device 21 is a general automatic light control device generally used in an optical device such as a digital printing device, and is a light L ₁ emitted from the light source lamp 8.
Y (yellow) dimming filter 21a for blocking (removing) B (blue) monochromatic light in (white light) and M (magenta) dimming filter 21b for blocking (removing) G (green) monochromatic light And C for blocking R (red) monochromatic light
(Cyan) dimming filter 21c.

Here, each of the dimming filters 21a to 21c
, Respectively of the light L ₁ optical axis M ₂ perpendicular Z ₁ -Z ₂ direction,
I.e. so that it can be continuously moved in a direction toward or away from the optical axis M _2. And
When each dimming filter 21a~21c is positioned to maximize Z ₂ side (opening position), i.e. when maximum away from the optical axis M _2, they become the open state (fully opened state).
In this case, the light control filter 21a~21c is to light L ₁ emitted (portion to originally enter the color wheel) from the light source lamp 8, in particular it does not affect. That is,
Light L ₁ emitted from the light source lamp 8 is introduced into the color wheel 9 almost as it is.

On the other hand, each of the dimming filters 21a to 21c is
Limit Z₁Side (fully closed position), that is, the optical axis
M_TwoWhen fully approached, they are fully closed.
You. At this time, each of the dimming filters 21a to 21c is a light source.
Light L emitted from lamp 8 ₁From the dimming filter 21
Almost all light components (wavelength components) corresponding to a to 21c are blocked.
Cover (removal). In addition, each of the dimming filters 21a to 21c
Is between the open position and the fully closed position (intermediate position)
Is radiated from the light source lamp 8 according to the position (opening degree).
Light L₁Corresponding to the dimming filters 21a to 21c
A part of the light component is shielded (removed).

Then, the automatic light control device 21
For each light L ₁ (monochromatic light) of R, G, and B, the amount of light incident on the digital micromirror device 10 is adjusted.
Hereinafter, the light amount adjustment method according to the present invention will be described with reference to the case of adjusting the light amount of G light (G light) as an example. When a color filter that transmits G light (hereinafter referred to as “G color filter”) in the color wheel 9 is located in the optical path, only the G light in the white light emitted from the light source lamp 8 passes through the G color filter. (Other light is absorbed and
This G light is incident on the digital micromirror device 10 via the integrator rod 24 and the condenser lenses 22 and 23.

The M dimming filter 21b is arranged at a predetermined position (opening degree) between the open position and the fully closed position according to the photosensitive characteristics of the photographic paper 7 or other exposure conditions. At this time, the M light control filter 21b shields (removes) the G light in the white light emitted from the light source lamp 8 according to the position (opening degree). Accordingly, the amount of G light incident on the digital micromirror device 10 is reduced according to the position (opening) of the M light control filter 21b.
Thus, the G light digital micromirror device 10 can be used in accordance with the photosensitive characteristics of the photographic paper 7 or other exposure conditions.
The amount of light incident on the photographic paper 7 and thus the amount of exposure of the photographic paper 7 are adjusted.

When the M dimming filter 21b is inserted into the optical path in order to adjust the amount of G light incident on the digital micromirror device 10, the presence or absence of the M dimming filter 21b or the degree of insertion is described. (That is, whether or not the light beam is blocked), the optical axis M ₂
In some cases, the light amount unevenness may occur in a cross section perpendicular to the direction. However, such light amount unevenness is diffused or eliminated by the integrator rod 24 having a light beam diffusing action, and the light incident on the digital micromirror device 10 is made uniform (uniform surface irradiation light is obtained).

As shown in FIG. 4, in the light source lamp 8, a part of the light emitted from the luminous body 26 (filament) is reflected by the reflector 27 (reflecting mirror), and the M light control filter 21b ( Although it enters the automatic dimmer 21), in response to the reflection position, the incident angle ω are changed to the light incident surface X ₁ of the M dimming filter 21b of the reflected light. For example, next to α nearly 90 ° incident angle ω of the reflected light Y ₁ in the vicinity of the center of the reflector 27, the incident angle ω of the reflected light Y ₂ in the middle portion of the reflector 27, slightly smaller than the α next beta, the incident angle ω of the reflected light Y ₃ in the vicinity of the periphery of the reflector 27, the γ smaller than the beta. In FIG. 4, the positions where the reflected lights Y ₁ , Y ₂ , and Y ₃ intersect the light incident surface X ₁ are the fully closed position, the half open position (intermediate position), and the open position of the M light control filter 21b, respectively. Yes, it is.

As described above, various reflected lights having different incident angles ω are incident on the M light control filter 21b except in the case where the M light control filter 21b is in the open state.
Varies with the incident angle ω. Graphs G ₁ , G ₂ , and G _{3 in} FIG. 5 show light transmission of the M light control filter 21b when the incident angles ω of the reflected light to the M light control filter 21b are α, β, and γ, respectively. The graph shows the change characteristic of the ratio with respect to the wavelength, or the half-width between wavelengths.

As is apparent from FIG. 5, the angle of incidence ω is α
(Approximately 90 °), to β, γ,
The light shielding wavelength region or the half-value wavelength width shifts to the shorter wavelength side (hereinafter, this phenomenon is referred to as “wavelength shift”). The “half wavelength width” means that the light transmittance is a half value P ₀ of the maximum transmittance of the light control filter (1/5 of the maximum transmittance).
2) means a region between wavelengths or a wavelength range.
For example, in the graph G ₁ in FIG. 5, a half wavelength in width between it is approximately 490～610Nm. Therefore, due to the wavelength shift, the half-value wavelength width (wavelength characteristic) of light transmitted (passed) through the M light control filter 21b (however, diffused by the integrator rod 24).
Slightly shifts according to the position (opening) of the M light control filter 21b.

The graphs T ₁ , T ₂ , and T _{3 in} FIG. 6 indicate that the M dimming filter 21b is near the open position, the middle position,
M light control filter 21b when located at the fully closed position
Shows the change characteristic of the light transmittance with respect to the wavelength, or the half-width between the wavelengths (however, the integrator rod 24).
Was spread by). Note that the half value here means ((maximum transmission amount) − (minimum transmission amount)) /
Means 2 points. As is clear from FIG.
As the dimming filter 21b moves from the open position to the intermediate position and the fully closed position, the light shielding wavelength region or the half-value wavelength interval shifts to the shorter wavelength side (wavelength shift).

Therefore, when this wavelength shift falls within the wavelength range of the G light transmitted by the G color filter of the color wheel 9, the wavelength characteristic of the G light transmitted through the G color filter and diffused by the integrator rod 24 is changed. , M
It changes (affected) according to the position (opening) of the light control filter 21b, and as a result, the digital micromirror device 10
The color shift occurs in the light incident on the light source.

Therefore, in this automatic light control device 21, based on such knowledge, the half value wavelength width of the transmitted light of the M light control filter 21b is determined by the half value wavelength generated by the difference in the position of the M light control filter 21b. The wavelength shift of the wavelength width is preferably set so as to occur in a wavelength region outside the half-value wavelength width of the transmitted light of the G color filter so as to prevent the occurrence of color shift. That is, the half-wavelength width of the transmitted light of the G color filter required by the photographic paper 7 is in a wavelength region where the wavelength shift does not reach (for example, a wavelength region indicated by R in FIG. 6).
The half value wavelength width of the transmitted light of the M light control filter 21b is preferably set so as to fall within the range.

In other words, regardless of the position (opening) of the M light control filter 21b, the longer wavelength end of the half value wavelength width of the M light control filter 21b is longer than the half value wavelength width of the G color filter. The short wavelength side end of the half-wavelength width of the M dimming filter 21b is located on the longer wavelength side than the wavelength side end, and is shorter than the short wavelength side end of the half-width of the G color filter. The wavelength characteristic (half-value wavelength width) of the M light control filter 21b is set so as to be positioned at. FIG.
The wavelength region indicated by R in the middle is set to a wavelength region where the light transmittance (light blocking ratio) is substantially constant regardless of the position (opening degree) of the M light control filter 21b.

The light amount adjusting method according to the present invention will be described with reference to the case where the light amount of the G light cut out by the G color filter of the color wheel 9 is adjusted using the M light adjusting filter 21b of the automatic light adjusting device 21 as an example. However, when adjusting the light amount of the B light cut out by the B color filter using the Y light control filter 21a, or when adjusting the light amount of the R light cut out by the R color filter using the C light control filter 21c It goes without saying that a similar light amount adjustment method is used.

[Brief description of the drawings]

FIG. 1 is a schematic elevation view showing a schematic configuration of a digital printing apparatus using a light amount adjusting device according to the present invention.

2A is a plan view of a digital micromirror device, FIG. 2B is an enlarged plan view of a micromirror constituting the digital micromirror device shown in FIG. 2A, and FIG. Is an elevation view of a micromirror.

FIG. 3 is a side view of an exposure processing unit of the digital printing apparatus shown in FIG.

FIG. 4 is an enlarged side view of a part around a light source lamp of the exposure processing unit shown in FIG. 3;

FIG. 5 is a graph showing a shift characteristic (wavelength shift) of the half value wavelength width of the M light control filter of the automatic light control device with respect to the light incident angle.

FIG. 6 is a graph showing a shift characteristic (wavelength shift) of the half value wavelength width of the M light control filter of the automatic light control device with respect to the filter position (opening degree).

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Digital printing apparatus, 2 ... Exposure processing part, 3 ... Development processing part, 4 ... Drying processing part, 5 ... Paper magazine, 6 ...
Paper roller, 7: photographic paper, 8: light source lamp, 9 ...
Color foil, 10 ... Digital micro mirror device, 1
DESCRIPTION OF SYMBOLS 1 ... Printing lens, 12 ... Developing solution tank, 13 ... Conveyance roller, 14 ... Frame part, 15 ... Micromirror part, 16 ... Micromirror, 16a ... Micromirror, 16b ... Micromirror, 17 ... Mirror plate, 18 ... York, 1
9 ... pillar, 20 ... board, 21 ... automatic light control device, 21a ...
Y dimming filter, 21b ... M dimming filter, 21c ... C
Dimming filter, 22: first condenser lens, 23: second condenser lens, 24: integrator rod, 2
6: luminous body, 27: reflector.

Claims (7)

[Claims] 1. Light emitted from a light source lamp is made incident on a digital micromirror device displaying an image,
A light amount adjusting device for an optical device adapted to irradiate a light source working medium with reflected light of the digital micromirror device accompanied by the image, wherein an optical path between the light source lamp and the digital micromirror device is provided. And an automatic light control device having a light control filter is provided, and by operating the light control filter, the amount of light incident on the digital micromirror device is adjusted. Light intensity adjustment device. 2. The light amount adjusting device according to claim 1, wherein a light beam diffusing member having a light beam diffusing function is provided in an optical path on the digital micromirror device side with respect to the automatic light adjusting device. 3. A color separation filter device having a plurality of color filters is provided in an optical path on a digital micromirror device side with respect to the automatic light control device. The light amount adjusting device according to claim 1, wherein a width of the light amount adjusting device is wider than a half-value wavelength width of transmitted light of a color filter corresponding to the light control filter in the color separation filter device. 4. The half-wavelength width of light transmitted through the light control filter is different from the half-wavelength width of light transmitted through the color filter by a shift of the half-wavelength width generated by the operation of the light control filter. The light amount adjusting device according to claim 3, wherein the light amount adjusting device is set so as to occur in an area. 5. A light amount adjusting device for an optical device, comprising: a light source lamp; and a color separation filter device provided with a plurality of color filters for separating light emitted from the light source lamp. An automatic light control device having a light control filter is provided in an optical path between the light source lamp and the color separation filter device. By operating the light control filter, the output light amount of the color separation filter device is provided. A light amount adjusting device characterized in that the light amount is adjusted. 6. The half-wavelength width of transmitted light of the dimming filter is wider than the half-wavelength width of transmitted light of a color filter corresponding to the dimming filter in the color separation filter device. The light amount adjusting device according to claim 5, wherein: 7. The half-wavelength width of the transmitted light of the light control filter is different from the half-wavelength width of the light transmitted through the color filter by a shift of the half-wavelength width generated by the operation of the light control filter. The light amount adjusting device according to claim 6, wherein the light amount adjusting device is set so as to occur in an area.