JPH0376724B2 - - Google Patents

Description

[Detailed description of the invention] The present invention will be explained in the following order.

Table of Contents (1) Technical Field of the Invention (2) Background Art of the Invention (3) Problems of the Background Art (4) Purpose of the Invention (5) Summary of the Invention (6) Embodiments of the Invention (7) Effects of the Invention [Invention Technical Field] The present invention relates to a laser color recording method in which a plurality of light beams having different wavelengths are modulated and combined into one beam, and the combined beam is used to perform color recording on a recording member.

[Background Art of the Invention] As shown in FIG. 1, a conventional laser color recording device records each image using laser beams of different wavelengths from three laser light sources (red light, green light, blue light) 1 to 3. Based on the information, the light is modulated by acousto-optic modulators (AOMs) 4 to 6, respectively, and combined into one beam by dichroic mirrors 7 to 9. Color recording is performed by deflecting this combined beam by a deflecting means 10 such as a rotating polygon mirror and scanning the recording member 12 through an imaging lens 11 such as an f-theta lens.

[Problems in the background art] An f-theta lens, which is an imaging lens for converging laser beams deflected by a rotating polygon mirror to one point and scanning them, is capable of focusing the laser beams on each laser beam by transmitting the combined beam as in this case. Since the wavelengths of the laser beams differ, the scanning line length in one scan differs depending on each laser beam. Therefore, as shown in FIG. 2, an error occurs in the imaging position of each laser beam, and a shifted image is recorded for each color. Hereinafter, this will be referred to as chromatic aberration of magnification. In addition, in order to correct this chromatic aberration of magnification, various glasses with different dispersions are used,
There is a method of correcting this by introducing a combination lens with concave and convex surfaces, but this requires manufacturing a highly accurate lens for correction, resulting in a problem that the device becomes expensive.

[Object of the Invention] An object of the present invention is to provide a chromatic aberration correction method in a laser color device that corrects the influence of chromatic aberration of magnification and enables accurate color recording.

[Summary of the Invention] The present invention modulates three light beams with different wavelengths λ ₁ , λ ₂ , and λ ₃ and combines them into one beam, and scans a predetermined position of a recording member with the combined beam. In the laser color recording method for color recording, a slit is placed on the scanning optical path of the clock generating light beam, and the light beams passing through the slit are sensitive to the light beams of wavelengths λ ₁ , λ ₂ , and λ ₃ . The present invention provides a chromatic aberration correction method in a laser color recording apparatus in which a recording timing clock for each light beam is generated by scanning light received by a light receiving section and scanning light received by each light receiving section.

[Embodiment of the Invention] An embodiment of the present invention will be described with reference to FIG.
In the figure, 30 is a multi-wavelength laser light source, 31 to 3
3 is a half mirror, 34 is a reflective mirror, 35-3
7 is a filter that selects and transmits a desired laser beam from the laser beam of the multi-wavelength laser light source; 38 to 40 are acousto-optic modulators (AOMs) that perform light modulation based on each color information; 41 is a reflecting mirror; 42 to 44 is a dichroic mirror, 45 is a rotating polygon mirror, 46
47 is a recording member such as a film, 48 and 49 are reflective mirrors that direct the recording timing clock generation beam toward the slit 50, 51 is a concave mirror, and 55 to 57 are respectively a light receiving element that receives light through filters 52, 53, and 54 that transmit blue, green, and red light beams;
58 is an image information source, 59 to 61 are image information sources 58
buffers each storing color information from 62
-64 are AOM drivers that drive the AOMs 38-40, respectively, based on the color information. In the present invention, a case will be described in which a multi-wavelength laser light source is used as the laser light source, but three laser light sources with different wavelengths as shown in FIG. 1 may also be used. In addition, half mirrors 31 to 33,
Reflection mirror 34, filter 3 that selects and transmits desired laser light from the laser light of the multi-wavelength laser light source.
The portions 5 to 37 may be replaced with dichroic mirrors to obtain desired laser beams.

Next, the operation will be explained.

A laser beam emitted from the multi-wavelength laser light source 30 is divided into four laser beams via half mirrors 31 to 33 and a reflecting mirror 34, respectively. Half mirror 3 of the 4 laser beams
The laser beam reflected by 1 is used as a recording timing clock generation beam, and the other three are passed through filters 35 to 37 to become blue laser beams B,
It is divided into a green laser beam G and a red laser beam R, respectively. Each laser beam is
Light is modulated by AOMs 38-40 and combined into one laser beam via dichroic mirrors 42-44. Then, this combined laser beam is deflected by a rotating polygon mirror 45 and scanned over a recording member 47 via an imaging lens 46, thereby performing half mirror recording.

On the other hand, the recording timing clock generation beam is reflected by a reflecting mirror 41 and is reflected by a rotating polygon mirror 4.
5, the imaging lens 46 and the reflecting mirror 4
8, 49, and is condensed by a concave mirror 51 through a slit 50. The focused light beam passes through filters 52, 53, which transmit blue, green, and red light beams.
The light is received by light receiving elements 55, 56, and 57 via 54, respectively. The recording timing clocks B', G', and R' received by each light receiving element are sent to buffers 59, 60, and 61, respectively, and the color information from the image information source 58 stored in each buffer is transferred to the recording timing clock. Each AOM is synchronized with B′, G′, and R′.
It is sent to drivers 62, 63, and 64. And each AOM driver 62, 63, 64 is
The AOMs 38, 39, and 40 are driven to perform optical modulation of each laser beam. In the present invention, each light receiving element may be arranged behind the slit 50 to detect each recording timing clock B', G', R'.

FIG. 4 shows a timing chart of recording timing clocks B', G', and R' in one scan.
At time _t0 , when the recording timing clock B' is detected by the light receiving element 55, light modulation is performed based on the blue color information in synchronization with this clock, and as shown in FIG. Blue information is recorded at the L ₀ position. Then, after time t ₁ has passed,
When the recording timing clock G' is detected by the light receiving element 56, light modulation based on the green information is performed in synchronization with this clock, and the green information is recorded at the position _L0 . Furthermore, after t ₂ elapses, the recording timing clock is set by the light receiving element 57 and the light receiving element 55.
When R′ and B′ are respectively detected, L ₀
Red information is recorded at the position L1, while blue information is recorded at the _L1 position. Thereafter, after time t _o has passed (when passing through the center of the scanning length), recording timing clocks B', G', and R' are simultaneously detected by each light receiving element, and recording is simultaneously performed at position L _o . .

[Effects of the Invention] As described above, the present invention can easily correct the chromatic aberration of magnification caused by the f-theta lens by individually controlling the recording timing of the recording laser beam for each color. Color recording can be performed.

[Brief explanation of drawings]

1 and 2 are diagrams for explaining a conventional laser color recording device, FIG. 3 is a configuration diagram showing an embodiment of the present invention, and FIG. 4 is a timing diagram of a recording timing clock in the present invention. FIG. 5 is a diagram for explaining the recording operation in the present invention. 38-40... Acousto-optic modulator, 45... Rotating polygon mirror, 46... Imaging lens, 50... Slit, 51...
Concave mirror, 52-54...Filter, 55-57...
Light receiving element.

Claims (1)

[Claims] 1. Three light beams with different wavelengths λ ₁ , λ ₂ , and λ ₃ are modulated and combined into one beam, and a predetermined position of the recording member is scanned with the combined beam, thereby producing a color image. In the laser color recording method for recording, a slit is placed on the scanning optical path of the clock generation light beam, and the light beam transmitted through the slit is detected by a light receiving device that is sensitive to the light beams of wavelengths λ ₁ , λ ₂ , and λ ₃ . 1. A chromatic aberration correction method for a laser color recording apparatus, characterized in that a recording timing clock for each light beam is generated by the scanning light received by each light receiving part.