JP2801089B2 - LCD printer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal printer for recording an image of a video signal on a recording medium such as a photosensitive material using a liquid crystal (LCD) panel.

[0002]

2. Description of the Related Art Generally, each pixel of a liquid crystal panel has an aperture ratio of less than 100%. Therefore, when an image of a video signal is recorded on a photosensitive material by the liquid crystal panel, black stripes or black stripes are formed by a non-opening portion of the liquid crystal panel. Since white stripes (in the case of a negative photosensitive material) occur in the photosensitive material, the dynamic range of density cannot be increased.

Conventionally, as a liquid crystal printer of this type, in order to solve the above-mentioned problems, a liquid crystal panel in which both the vertical and horizontal aperture ratios of the pixel openings are 50%, that is, the area aperture ratio is 25%, is used. A method has been proposed in which a non-opening portion having an area of 75% of the entire area is interpolated by relatively moving the panel and the photosensitive material stepwise in the XY directions. Therefore, in this liquid crystal printer, when exposing 100% of the area,
The liquid crystal panel performs 2 × 2 pixel scan.

[0004]

However, liquid crystal panels having a pixel aperture ratio of 25% are quite special at present when brighter displays are required, and therefore such liquid crystal panels are generally not available. Since it is difficult, there is a problem that the liquid crystal printer itself becomes expensive.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned drawbacks of the prior art and to provide an inexpensive liquid crystal printer using a generally available liquid crystal panel.

[0006]

In the liquid crystal printer according to the present invention, the vertical and horizontal aperture ratio of each pixel exceeds 50%, that is, the area aperture ratio exceeds 25%, and an image corresponding to a video signal is recorded on a recording medium. Liquid crystal panel, and the liquid crystal panel and the recording medium move stepwise in the short side direction of the liquid crystal panel display section frame and in the long side direction orthogonal thereto in units of ピ ッ チ pitch of the pixel relatively for each pixel. And moving means for moving the object.

[0007]

[Function] Liquid crystal cells are arranged two-dimensionally and the optical aperture ratio is 25%
Using a liquid crystal panel 10 that exceeds the maximum, the liquid crystal panel and the recording medium are step-moved in a predetermined XY direction at a half of the liquid crystal cell pitch to interpolate between pixels, and an image corresponding to the video signal is recorded on the recording medium. Record. This eliminates black (white) stripes between pixels in a general-purpose liquid crystal panel.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of the liquid crystal printer according to the present invention will be described in detail with reference to the accompanying drawings.

Referring to FIGS. 1 and 2, the liquid crystal printer of the embodiment uses a liquid crystal panel 10 in which the vertical and horizontal aperture ratio of pixels exceeds 50% and the area aperture ratio exceeds 25%. The material 12 is moved stepwise in the X and Y directions at a half pitch of a pixel.

A light source (not shown) is arranged above the liquid crystal panel 10 in a direction orthogonal to the drawing of FIG.
A photosensitive material 12 is arranged below the photosensitive material 10. Therefore, when the brightness of each pixel of the liquid crystal panel 10 is modulated, an image corresponding to the video signal is recorded on the photosensitive material 12. LCD panel 10 is X
The motor 14 and the gear 16 step in the X direction at a half pitch of a pixel, and the Y motor 18 and the gear 20 step in the Y direction at a half pitch of a pixel. The X motor 14 and the Y motor 18 are controlled. It is controlled by the unit 22. Note that the numerals shown in the photosensitive material 12 in FIG. 1 indicate the number of exposures by the step movement. That is, exposure is performed once at each of the points 1, 2, 3, and 4 in FIG. 2B.

The control unit 22 further includes a frame memory (not shown) for storing a video signal of an image recorded on the photosensitive material 12, and outputs a recording signal corresponding to the video signal to the row driver 24 and the column driver 26. I do. The row driver 24 outputs a drive signal for recording to the pixels of each row of the liquid crystal panel 10 and the column driver 26
Outputs a common signal for selecting pixels in each column of the liquid crystal panel 10.

As shown in FIG. 2A, each pixel of the liquid crystal panel 10 has an opening 11 having a horizontal x of 55 μm and a vertical y of 60 μm, for example.
, The distance from the opening 11 of the adjacent pixel in the main scanning direction is 25 μm
The distance between the opening 11 of the adjacent pixel in the sub-scanning direction is 28 μm
It is. That is, the liquid crystal panel 10 has an aperture ratio of 47%.
For example, it is available as a liquid crystal panel for a monochrome liquid crystal television. In this embodiment, as shown in FIG. 2B, the liquid crystal panel 10 is 40 μm in the X direction (Δx shown).
2 and a step movement in the Y direction by 44 μm (Δy shown).
As shown in (c), one pixel is (x + Δx) × (y + Δ
The image of y) is recorded on the photosensitive material 12.

Next, the operation of the above embodiment will be described. When a video signal in frame units is input, the control unit 22 stores the video signal in a frame memory and outputs a recording signal for the first line to a row driver 24 and a column driver 26. The row driver 24 serially outputs a drive signal for recording of the first line to each pixel of the first row of the liquid crystal panel 10, and the column driver 26 outputs
Output a common signal for selecting the pixels in each column of the first line.

In this case, the control unit 22 controls the X motor 14 for each pixel of one line to control the liquid crystal panel 10 in the X direction.
Stepwise in the direction at half the pitch of the pixel. Accordingly, as shown in FIG. 1, the photosensitive material 12 is exposed once in an area where adjacent pixels do not overlap, and is exposed twice in an area where the adjacent pixels overlap.

When this scanning is completed, the liquid crystal panel 10 is step-moved in the Y direction by half the pitch of the pixels by controlling the Y motor 18, and the first line is again scanned as described above. Therefore, as shown in FIG. 1, the area of the photoconductor 12 indicated by the numeral "2" is exposed twice, and the area indicated by the numeral "4" is exposed four times. Hereinafter, similarly, when scanning of the second and third lines is performed, an image (latent image) of one frame is recorded on the photoconductor 12.

Here, in the liquid crystal panel 10 of the embodiment,
The distance between the opening 11 of the adjacent pixel in the X direction is 25 μm, the distance between the opening 11 of the adjacent pixel in the Y direction is 28 μm, and
Since the step moves in the X direction in steps of 40 μm and the step moves in the Y direction in steps of 44 μm, the openings 11 of the adjacent pixels overlap, but the overlap with the openings 11 of the adjacent pixels in the X direction is 15 μm. Since the distance between the adjacent pixel and the opening 11 is 16 μm, the density unevenness is as shown in FIG. That is, the density unevenness pitch in the X direction is 40 μm, and the density unevenness pitch in the Y direction is 44 μm. That is, there is an effect that the spatial frequency of density unevenness is high and is not noticeable.

FIG. 3 also shows that the liquid crystal panel of FIG. 2A is used, and the liquid crystal panel and the photosensitive material are step-moved relatively in the X and Y directions. FIG. 8 is an explanatory view of exposure when stepping to a contact position that does not interfere with an adjacent pixel without being performed.
25 μm and Δy = 28 μm. The region exposed twice or four times is larger than in this embodiment, and the density unevenness pitch in the X direction is
The density unevenness pitch in the y direction is 80 μm and the density unevenness pitch in the y direction is 88 μm, which is twice as large as the density unevenness pitch in the present embodiment.

FIG. 4 shows a pixel of a liquid crystal panel 30 according to another embodiment. Each pixel of the liquid crystal panel 30 has an opening 32 having, for example, a horizontal x of 112 μm, a vertical y of 105 μm, a distance from an opening 32 of an adjacent pixel in the X direction of 49 μm, and an opening 32 of an adjacent pixel in the Y direction. Is 85 μm. That is, the liquid crystal panel 30 has an area aperture ratio of pixels of 38.4%, and can be obtained, for example, as a liquid crystal panel of a monochrome liquid crystal television.

FIG. 5 shows that the liquid crystal panel 30 is moved step by step in the X scanning direction for each pixel in units of 1/2 pitch of the pixels, that is, in units of 80.5 μm, and in the Y direction in steps of 1/2 pitch of the pixels, that is, in units of 95 μm. FIG. 9 is an explanatory view of exposure when the lens moves. That is, in this embodiment, the pixels in the even-numbered rows are exposed with a shift of ピ ッ チ pitch from the pixels in the odd-numbered rows. Further, the pixels in the even columns are exposed with a shift of １ ／ pitch from the pixels in the odd columns.

FIG. 6 shows that the liquid crystal panel of FIG. 4 is used to move the liquid crystal panel and the photosensitive material stepwise in the X and Y directions in the same manner. FIG. 4 is an explanatory view of exposure when a step is moved to a contact position that does not interfere with a pixel, and Δx = 49 μm,
y = 85 μm. The region exposed twice or four times is shown in FIG.
It is larger and the pitch of the density unevenness is twice as large as that in FIG. 5, resulting in an extremely unsightly image. Therefore, regardless of the liquid crystal panel having the shape shown in FIG. 2A or the liquid crystal panel having the shape shown in FIG. Can be created.

FIG. 7 shows a case where the liquid crystal panel 30 of the second embodiment is used and the total exposure time of RGB is 86.4 seconds, 43.2 seconds, and 21.6 seconds without step movement as in the present invention. 4 shows the dynamic range of the reflection density D of a print when the exposure is performed for 21.6 seconds after the step movement at a half pitch of the above. As shown in FIG. 7, the dynamic ranges were 1.14, 1.6, 1.73, and 2.1, respectively, and the dynamic range of the present example was observed to be the largest.

This time, points 1 and 2 in FIG.
Although an example in which exposure is performed once at each of points 3 and 4 is shown, the same effect can be obtained by performing continuous exposure while moving in the order of 1, 2, 3, and 4 with the light source ON. Needless to say.

[0023]

As described above, according to the present invention, it is possible to use an LCD panel used for a normal liquid crystal TV having an area aperture ratio of each pixel exceeding 25%, and as a result, a low-cost printer device is used. Can be formed. Further, the dynamic range of density can be increased without noticeable density unevenness.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing a configuration and an exposure example of an embodiment of a liquid crystal printer according to the present invention.

2A is an explanatory diagram showing pixels of the LCD panel of FIG. 1, FIG. 2B is an explanatory diagram showing pixel step driving of the LCD panel of FIG. 1, and FIG. 2C is a diagram of FIG. FIG. 4 is an explanatory diagram illustrating pixels exposed by the illustrated step driving.

FIG. 3 is an explanatory view showing an example of exposure using a conventional LCD panel.

FIG. 4 is an explanatory diagram showing pixels of an LCD panel used in a second embodiment of the liquid crystal printer according to the present invention.

FIG. 5 is an explanatory diagram showing an example of exposure by the LCD panel of FIG. 4;

FIG. 6 is an explanatory diagram showing an example of exposure by a conventional LCD panel similar to the LCD panel of FIG. 4 in the arrangement example of pixels.

FIG. 7 is a graph showing a dynamic range in a case where exposure is performed by the conventional example and the LCD panel of FIG. 4;

[Explanation of symbols]

 10,30 LCD panel 11,32 opening 12 photosensitive material 14,18 motor 16,20 gear 22 control unit 24,26 driver

Claims (1)

(57) [Claims] 1. A liquid crystal panel for recording an image corresponding to a video signal on a recording medium, wherein the vertical and horizontal aperture ratio of each pixel exceeds 50%, that is, the area aperture ratio exceeds 25%. Moving means for moving the medium so as to step in the short side direction of the liquid crystal panel display unit frame and in the long side direction orthogonal thereto in units of 画素 pitch of the pixel. A liquid crystal printer characterized by exposure.