JP2006227545A - Optical scanner and printer using the optical scanner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical scanner which is low-noise, highly reliable, extremely compact, and low-cost, and to provide a printer. <P>SOLUTION: A scanning system is constructed with a deflector which controls a photonic crystal (a second photonic crystal 13), formed of a ferroelectric, with a voltage applied to the photonic crystal (a voltage control portion 14), and a deflection angle magnifier which magnifies the deflection angle of deflected light formed of the ferroelectric or a dielectric (a first photonic crystal 12), wherein at least the photonic crystal (the first photonic crystal 12) constituting the deflection angle magnifier is constructed so as to make only one band corresponding to light from a light source be present. With this construction, the deflection angle of laser light 17 is possibly made 120° or more, and the compact optical scanner is realized. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an optical scanning technique, and more particularly to an optical scanning device used for a printer and a printer using the same.

  There are various types of printers that are currently popular, and one of them is an optical writing method that performs optical writing. A representative example of the optical writing method is an electrophotographic method.

  A typical example of the self-emission type in the optical writing method is a silver salt method. In the silver salt method, light is directly written on a photographic paper, and when light is irradiated, the color of the light irradiated after development is developed, and there are three colors: red (R), green (G), and blue (B). Full-color printing is possible by writing with the light of.

  In addition, a self-coloring type that has recently attracted attention is one that uses a photochromic material. A photochromic material is a material whose color changes reversibly by light, and the part irradiated with light changes to the color of the light. Since it can be returned, it is expected to be a full-color rewritable paper that can be repeatedly written and erased by light.

  On the other hand, as a conventional optical scanning device used in the above-described optical writing method, there is a polygon mirror type optical scanning device that is currently most employed in an electrophotographic printer or the like. In the polygon mirror system, light can be scanned by rotating a polygon mirror having a plurality of reflecting surfaces at high speed and applying light to the reflecting surfaces.

Hereinafter, a conventional optical scanning device will be described.
FIG. 12 is a diagram for explaining the polygon mirror system disclosed in Japanese Patent Laid-Open No. 2003-202510 (Patent Document 1).

  In the figure, reference numeral 251 denotes a light source means, which comprises a four-beam semiconductor laser that emits four beams. 252 is a collimator lens, 253 is an aperture, 232 is a cylindrical lens, 202 is a polygon mirror as an optical deflector, 222 is a spherical lens (first scanning lens), 226 is a toric lens (second scanning lens), 255 Is a parallel plate glass as an optical member (interval adjustment member), and in the sub-scanning direction according to the amount detected by the photodetector 230 (position shift information in the sub-scanning direction of a plurality of beams scanned on the photosensitive drum). Thus, the drawing position (scanning start position) in the sub-scanning direction of a plurality of beams that scan the photosensitive drum (photosensitive member) 227 is adjusted.

  As another method of the conventional optical scanning device, an optical scanning device in which light emitting elements such as LEDs and organic ELs are arranged in an array has been proposed.

  FIG. 13 is a diagram for explaining an optical scanning device disclosed in Japanese Patent Laid-Open No. 9-226172 (Patent Document 2), which has a configuration in which organic EL elements are arranged in an array, and an arbitrary organic EL It is possible to scan the light by controlling the element to light up.

  In the optical scanning device shown in the figure, on a glass substrate 308, approximately the same number of signal electrodes 309 as the number of dots of the organic EL are arranged. Each signal electrode 309 is electrically connected to the transparent electrode 311 through the first contact hole 310 of the insulating film.

  The transparent electrode 311 is opposed to the electron injection electrode 315 across the hole transport layer 313 and the light emitting layer 314 in the second contact hole 312 of the insulating film.

  Since the second contact holes 312 of this insulating film correspond to the light emitting region, they are arranged on a straight line at equal intervals. The electron injection electrode 315 is electrically connected to the common electrode 318 in the first contact hole 316 of the protective film. The protective film second contact hole 317 is necessary to electrically connect the signal electrode 309 and the transparent electrode 311 because the protective film is formed between the signal electrode 309 and the transparent electrode 311.

  An optical scanning device using a large wavelength dispersion characteristic of a photonic crystal has also been proposed.

  FIG. 14 is a diagram for explaining an optical scanning device proposed in Japanese Patent Application Laid-Open No. 2001-13439 (Patent Document 3). Photo in which cylindrical silicon 432 is periodically arranged in a silicon oxide film 431. Using the nick crystal 430 and the wavelength tunable laser 410, the direction of the light beam in the photonic crystal 430 is changed by changing the current flowing through the wavelength controller of the wavelength tunable laser 410 and changing the wavelength from 650 nm to 660 nm. As a result, the optical scanning is performed by largely changing the deflection direction of the light beam.

  Further, in Japanese Patent Laid-Open No. 2001-75040 (Patent Document 4) proposed by the present applicant, a laser scanning system is constituted by a wavelength tunable laser and a photonic crystal, and laser light is scanned by changing the wavelength continuously. is doing.

  In addition, an optical position sensor, or a start position sensor and an end point position sensor are provided, and information from the sensors is fed back to correct the laser wavelength. This uses a special laser called a wavelength tunable laser, and the apparatus becomes expensive.

  In addition, in Japanese Patent Laid-Open No. 2003-149419 (Patent Document 5) proposed by the present applicant, an optical scanning device is composed of a wavelength tunable DBR semiconductor laser, a photonic crystal, and a coupling lens that causes laser light to enter the photonic crystal. It is composed.

  The wavelength tunable DBR semiconductor laser is a passive waveguide heating type semiconductor laser that is equipped with a heater that locally heats the waveguide and varies the refractive index. The wavelength of the laser light is changed to scan the laser light. Yes. This uses a special laser as in JP-A-2001-75040 (Patent Document 4), and the apparatus becomes expensive.

  As other conventional techniques, as described later, JP-A-11-70695 (Patent Document 6), JP-A-2003-54030 (Patent Document 7), JP-A-2003-1864 (Patent Document 8), D.C. There is also Scrymgeour, N. Malkova, S. Kim and V. Gopalan, Appl. Phys. Lett., 82, 3176 (2003) (Non-patent Document 1).

JP 2003-202510 A JP-A-9-226172 JP 2001-13439 A JP 2001-75040 A JP 2003-149419 A JP-A-11-70695 JP 2003-54030 A JP 2003-1864 A H. Kosaka et al., Rhys. Rev. B 58, R10096 (1998) D. Scrymgeour, N. Malkova, S. Kim and V. Gopalan, Appl. Phys. Lett., 82, 3176 (2003) Kawashima Ikue, Takahashi Hiroyuki, Hirano Narunobu, Optics 32, 12, 707 (2003)

  However, the above-described polygon mirror method requires a mechanical drive unit that mechanically rotates the mirror, which causes a problem in terms of reliability that mechanical wear occurs, and noise is generated. There is a problem. Furthermore, there is a problem that the printer occupies a relatively large space and becomes large.

  On the other hand, an optical scanning device in which light emitting elements such as LEDs and organic ELs are arranged in an array illuminates an arbitrary light emitting element by arranging the light emitting elements, so there is no mechanical drive and no mechanical wear or noise is generated. Also, the space occupied by the printer device is relatively small, and the printer device can be downsized.

  However, in an optical scanning device in which LEDs are arranged in an array as light emitting elements, it is very difficult to produce a very long LED array chip, so it is necessary to mount a plurality of LED array chips side by side. Since accuracy greatly affects the print quality, it is necessary to implement with high accuracy, leading to an increase in cost.

  Further, the LED array has a problem of light emission variation that greatly affects the print quality. Although there is a means for adjusting part by bit by cutting a part of the electrode with a laser beam as disclosed in Japanese Patent Application Laid-Open No. 11-70695 (Patent Document 6), the number of processes increases. It leads to cost increase.

  In an optical scanning device in which organic EL elements are arranged in an array as a light emitting element, as shown in Japanese Patent Laid-Open No. 9-226172 (Patent Document 2) (see FIG. 13), long ones can be manufactured in a lump. Therefore, since there is no mounting process, the cost can be reduced, and the variation in light emission is relatively small. However, the organic EL element has a problem that the lifetime is shorter than that of the LED, and the luminance gradually decreases as the cumulative lighting time becomes longer.

  To solve this problem, as disclosed in Japanese Patent Application Laid-Open No. 2003-54030 (Patent Document 7), the light emission intensity per unit area is lowered due to the structure, or the life is extended, or Japanese Patent Application Laid-Open No. 2003-1864 ( As in Patent Document 8), it is possible to arrange multiple lines of organic EL arrays, and switch to another line when the line in use reaches the end of its life. Thus, there is a problem that the advantages of low cost and small size of the organic EL are impaired. Furthermore, the organic EL array has a short lifetime and is not a fundamental solution to the problem of gradually decreasing brightness.

  In addition, the optical scanning device composed of the photonic crystal and the wavelength tunable laser does not have a mechanical drive unit, generates no noise, and can downsize the printer device. However, it is necessary to use a special laser called a wavelength tunable laser, and there is a problem that the apparatus becomes expensive.

  SUMMARY OF THE INVENTION It is an object of the present invention to provide an optical scanning device and a printer that solve the above problems, have low noise, have high reliability, are extremely small, and are inexpensive. The purpose of each claim will be specifically described below.

a) It is an object of the present invention to provide an optical scanning device with low noise, high reliability, small size, and low cost.

b) An object of the invention described in claims 3 to 8 is to provide an optical scanning device with low noise, high reliability, small size, low cost, and low light loss and stray light. Yes.

c) It is an object of the present invention to provide an optical scanning device that is low in noise, highly reliable, small in size, inexpensive, and capable of high-speed scanning.

d) An object of the invention described in claim 11 is to provide an optical scanning device which is low noise, high in reliability, small in size, inexpensive and used in a multicolor printer.

e) It is an object of the present invention to provide an optical scanning device that is low in noise, highly reliable, small in size, inexpensive, and used in a full color printer.
f) It is an object of the invention of claim 13 to provide an optical scanning device with low noise, high reliability, small size, and low cost.

g) It is an object of the present invention to provide a printer that is low in noise, high in reliability, small in size and inexpensive.
h) An object of the present invention is to provide a color printer which is low in noise, high in reliability, small in size and inexpensive.
i) It is an object of the present invention to provide a rewritable paper printer that is low in noise, highly reliable, small in size, and inexpensive.

  In the present invention, in order to achieve the above-described object, the scanning system is formed of a deflector which is controlled by a voltage applied to the photonic crystal and a ferroelectric material or a dielectric material. It is configured by a deflection angle expander that expands the deflection angle of the deflected light, and at least in the photonic crystal that forms the deflection expander, there is only one band for light from the light source. With this configuration, the deflection angle can be set to 120 ° or more, and a more compact optical scanning device can be realized. Hereinafter, the structure for each claim will be described.

a) The optical scanning device according to claim 1 and claim 2 includes a light source, a photonic crystal formed of a ferroelectric material, and a voltage control unit that controls a voltage applied to the photonic crystal formed of the dielectric material. An optical scanning device is composed of a deflector comprising: a deflection angle magnifier comprising a photonic crystal formed of a ferroelectric material or a dielectric, and a detector for detecting a scanning position, and the scanning position detected by the detector is determined. The signal is fed back to the voltage control unit of the deflector to scan the light, and the photonic crystal constituting the deflection angle expander is configured so that there is only one photonic band for the light from the light source. ing.

Here, the existence of only one photonic band for a certain light means that there is only one propagation state of the light in the photonic crystal. When there are two photonic bands, When two propagation states exist and there is no photonic band, light does not propagate in the photonic crystal (no light exists).
Therefore, it is possible to easily manufacture an optical scanning device that does not have a mechanical drive unit, does not vary in the amount of light, is very small, and does not require a special laser.

b) The optical scanning device according to claim 3 is the optical scanning device according to claim 1 or 2, wherein the light incident surface of the ferroelectric photonic crystal constituting the deflector and the surface from which the light exits. The antireflection means is provided on either of the two surfaces, the surface on which light is incident, or the surface on which light is emitted.
Therefore, it is possible to easily manufacture an optical scanning device that has no mechanical drive unit, does not vary in light quantity, is very small, does not require a special laser, and reduces unnecessary reflection.

c) The optical scanning device according to claim 4 is the optical scanning device according to claim 3, wherein the antireflection means is formed by arranging a structure having a triangular cross section with a period of 1/2 or less of the light source wavelength. Yes.
Therefore, it is possible to easily manufacture an optical scanning device that has no mechanical drive unit, does not vary in light quantity, is very small, does not require a special laser, and reduces unnecessary reflection.

d) The optical scanning device according to claim 5 performs the formation of the photonic crystal constituting the deflector and the arrangement of the structure having a triangular cross section in the same process.
Therefore, it is possible to easily manufacture an optical scanning device that has no mechanical drive unit, does not vary in light quantity, is very small, does not require a special laser, and reduces unnecessary reflection.

e) The optical scanning device according to claim 6 is the optical scanning device according to any one of claims 1 to 5, wherein the light of the ferroelectric or dielectric photonic crystal constituting the deflection angle expander is incident. Antireflection means is provided on either one of the surface and the surface from which light exits, or on either the surface on which light enters or the surface from which light exits.
Therefore, it is possible to easily manufacture an optical scanning device that has no mechanical drive unit, does not vary in light quantity, is very small, does not require a special laser, and reduces unnecessary reflection.

f) In the invention according to claim 7, in the optical scanning device according to claim 6, the antireflection means is configured such that a structure having a triangular cross section is arranged with a period of 1/2 or less of the light source wavelength.
Therefore, it is possible to easily manufacture an optical scanning device that has no mechanical drive unit, does not vary in light quantity, is very small, does not require a special laser, and reduces unnecessary reflection.

g) The optical scanning device according to claim 8 is the optical scanning device according to claim 7, wherein the formation of the photonic crystal constituting the deflection angle expander and the arrangement of the structure in which the cross section is a triangle shape are provided. It is done in the same process.
Therefore, it is possible to easily manufacture an optical scanning device that has no mechanical drive unit, does not vary in light quantity, is very small, does not require a special laser, and reduces unnecessary reflection.

h) The optical scanning device according to any one of claims 9 and 10 is configured by arranging two or more optical scanning devices according to any one of claims 1 to 8 in the main scanning direction or the sub-scanning direction.
Therefore, it is possible to easily manufacture an optical scanning device that does not have a mechanical drive unit, does not vary in light quantity, is very small, does not require a special laser, and has a high effective scanning speed.

i) The optical scanning device according to claim 11 is the optical scanning device according to claim 10, wherein two or more optical scanning devices having different light source wavelengths are arranged in the sub-scanning direction.
Therefore, it is possible to easily manufacture an optical scanning device that does not have a mechanical driving unit, does not vary in light quantity, is very small, does not require a special laser, and can scan light of different wavelengths.

j) An optical scanning device according to a twelfth aspect includes three or more types of optical scanning devices according to any one of the first to eighth aspects having different light source wavelengths arranged in the sub-scanning direction.
Therefore, it is easy to manufacture an optical scanning device that does not have a mechanical drive unit, does not vary in light quantity, is very small, does not require a special laser, and can scan three or more different wavelengths of light. Can do.

k) The optical scanning device according to claim 13 is the optical scanning device according to any one of claims 1 to 12, wherein the photonic crystal is formed of PLZT.
Therefore, it is possible to easily manufacture an optical scanning device that does not have a mechanical drive unit, does not vary in light quantity, is very small, does not require a special laser, and can scan light in the visible light region.

l) A printer according to a fourteenth aspect includes the optical scanning device according to any one of the first to tenth aspects, an image carrier, a developing device, a transfer device, and a fixing device.
Therefore, an electrophotographic printer with low noise, high reliability, very small size, and low cost can be easily manufactured.

m) The printer described in claim 15 includes the optical scanning device according to claim 12, a developing device, and a fixing device.
Therefore, a color printer is possible, and a silver salt color printer that is low in noise, highly reliable, extremely small and inexpensive can be easily manufactured.

n) A printer according to claim 16 comprises the optical scanning device according to any one of claims 1 to 13 and an ultraviolet light source.
Therefore, it is possible to easily produce a color printer for rewritable paper that can be printed on a rewritable paper made of a photochromic material and that is low in noise, highly reliable, extremely small, and inexpensive.

  As described above, according to the present invention, it is possible to easily manufacture an optical scanning device and a printer that are highly reliable, extremely small, and inexpensive. The effects of each claim will be described below.

a) The optical scanning device according to any one of claims 1 and 2 controls a voltage applied to a light source, a photonic crystal formed of a ferroelectric material, and a photonic crystal formed of a dielectric material. A deflector composed of a voltage controller, a deflection angle magnifier composed of a ferroelectric material or a dielectric material, and a photonic crystal having only one photonic band for light from the light source, and a detector for detecting a scanning position Since the optical scanning device is configured to scan the light by feeding back the signal at the scanning position detected by the detector to the voltage control unit of the deflector, there is no mechanical drive, no variation in light quantity, and special An optical scanning device that does not require a large laser and has a very large deflection angle can be easily manufactured.
Therefore, an optical scanning device with low noise, high reliability, small size, and low cost can be easily realized.

The optical scanning device according to claim 3 is the optical scanning device according to claim 1 or 2, wherein both the light incident surface and the light emitting surface of the ferroelectric photonic crystal constituting the deflector are provided. Or anti-reflection means on one of the light incident surface and the light emitting surface, so there is no mechanical drive, no variation in light quantity, very small size, special An optical scanning device that does not require a laser and reduces unnecessary reflection can be easily manufactured.
Therefore, it is possible to realize an optical scanning device with low noise, high reliability, small size, low cost, and low light loss and stray light.

c) The optical scanning device according to claim 4 is the optical scanning device according to claim 3, wherein the antireflection means is formed by arranging a structure having a triangular cross section with a period of 1/2 or less of the light source wavelength. Therefore, it is possible to easily manufacture an optical scanning device that has no mechanical drive unit, does not vary in light quantity, is very small, does not require a special laser, and reduces unnecessary reflection.
Therefore, it is possible to realize an optical scanning device with low noise, high reliability, small size, and low cost, and with little light loss and stray light.

d) In the optical scanning device according to claim 5, since the formation of the photonic crystal constituting the deflector and the arrangement of the structure having a triangular cross section are performed in the same process, there is no mechanical drive unit. Therefore, it is possible to easily manufacture an optical scanning device that does not vary in light quantity, is very small, does not require a special laser, and reduces unnecessary reflection.
Therefore, it is possible to realize an optical scanning device with low noise, high reliability, small size, and low cost, and with little light loss and stray light.

e) The optical scanning device according to claim 6 is the optical scanning device according to any one of claims 1 to 5, in which light of a ferroelectric or dielectric photonic crystal constituting a deflection angle expander is incident. The anti-reflection means is provided on either the surface that emits light and the surface that emits light, or either the surface that receives light or the surface that emits light. It is possible to easily manufacture an optical scanning device that has no variation, is very small, does not require a special laser, and reduces unnecessary reflection.
Therefore, it is possible to realize an optical scanning device with low noise, high reliability, small size, and low cost, and with little light loss and stray light.

f) In the invention according to claim 7, in the optical scanning device according to claim 6, the antireflection means has a structure having a triangular cross section arranged at a period of 1/2 or less of the light source wavelength. Therefore, it is possible to easily manufacture an optical scanning device that has no mechanical drive unit, does not vary in light quantity, is very small, does not require a special laser, and reduces unnecessary reflection.
Therefore, it is possible to realize an optical scanning device with low noise, high reliability, small size, and low cost, and with little light loss and stray light.

g) The optical scanning device according to claim 8 is the optical scanning device according to claim 7, wherein the photonic crystal constituting the deflection angle expander is formed, and the arrangement of the structure in which the cross section is triangular. Because it is performed in the same process, it is easy to manufacture an optical scanning device with no mechanical drive, no variation in light quantity, very small size, no special laser, and reduced unnecessary reflections. can do.
Therefore, it is possible to realize an optical scanning device with low noise, high reliability, small size, and low cost, and with little light loss and stray light.

Since the optical scanning device according to any one of claims 9 and 10 includes two or more of the optical scanning devices according to any of claims 1 to 8 arranged in the main scanning direction or the sub-scanning direction, It is possible to easily manufacture an optical scanning device that has no driving unit, does not vary in light quantity, does not require a special laser, has a very large deflection angle, and has a high effective scanning speed.
Therefore, it is possible to easily realize an optical scanning device with low noise, high reliability, small size, low cost, and capable of high-speed scanning.

An optical scanning device according to an eleventh aspect includes the optical scanning device according to the tenth aspect in which two or more optical scanning devices having different light source wavelengths are arranged in the sub-scanning direction. In addition, it is possible to easily manufacture an optical scanning device that does not vary in light quantity, does not require a special laser, has a very large deflection angle, and can scan light of different wavelengths.
Therefore, it is possible to easily realize an optical scanning device that is used in a multicolor printer with low noise, high reliability, small size, and low cost.

Since the optical scanning device according to claim 12 comprises three or more types of optical scanning devices according to any one of claims 1 to 8 having different light source wavelengths arranged in the sub-scanning direction, It is possible to easily manufacture an optical scanning device that does not have a dynamic drive unit, does not vary in light quantity, does not require a special laser, has a very large deflection angle, and can scan three or more different wavelengths of light. it can.
Therefore, it is possible to easily realize an optical scanning device that is low noise, high in reliability, small in size, inexpensive, and used in a full-color printer.

In the optical scanning device according to claim 13, since the photonic crystal of the optical scanning device according to any one of claims 1 to 12 is formed of PLZT, there is no mechanical driving unit, and there is no variation in light amount. Thus, an optical scanning device that does not require a special laser, has a very large deflection angle, and can scan light in the visible light region can be easily manufactured.
Therefore, it is possible to easily realize an optical scanning device that is low in noise, highly reliable, small in size, inexpensive, and usable with light in the visible light region.

The printer according to the fourteenth aspect includes the optical scanning device according to any one of the first to tenth aspects, an image carrier, a developing unit, and a transfer unit. A small, inexpensive and inexpensive printer can be easily manufactured.
Therefore, a high quality printer can be realized at low cost.

Since the printer according to claim 15 is constituted by the optical scanning device according to claim 12 and the fixing device, a silver-salt color printer is possible, low noise, high reliability, A small and inexpensive silver salt color printer can be easily manufactured.
Therefore, a high-quality color printer can be realized at low cost.

Since the printer according to claim 16 includes the optical scanning device according to any one of claims 1 to 13 and an ultraviolet light source, the printer can print on a rewritable paper made of a photochromic material, and A low noise, high reliability, small and inexpensive printer can be easily manufactured.
Therefore, a high-quality rewritable paper printer can be realized at low cost.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

<First embodiment>
An optical scanning device will be described as a first embodiment of the present invention.
FIG. 1 is a diagram showing the configuration of the optical scanning device of the first embodiment.

The optical scanning device shown in FIG. 1 includes a light source (semiconductor laser) 11, a first photonic crystal 12 formed of a dielectric (TiO ₂ ), and a second formed of a ferroelectric (PLZT). A photonic crystal 13, a voltage controller 14, and an optical scanning position detector (photodiode) 15 are included. In the figure, 16 is an image carrier (photosensitive drum), 17 is a laser beam, and 18 is a circular hole.

  Electrodes 131 and 132 are formed on both upper and lower surfaces of the second photonic crystal 13 made of ferroelectric (PLZT). A voltage control unit 14 is connected between the electrodes 131 and 132, and the voltage can be controlled and applied in the thickness direction of the second photonic crystal 13 formed of a ferroelectric (PLZT). It is like that.

  FIG. 2 is a top view of the optical scanning device shown in FIG. In the present embodiment, the first photonic crystal 12 is configured with a two-dimensional close-packed circular hole arrangement structure. FIG. 3 is a photonic band diagram of TM mode.

  A structure in which transparent materials having different refractive indexes are periodically arranged in a multidimensional manner is called a photonic crystal, and is known to have characteristics such as a photonic band gap, anisotropy, and high dispersibility.

  It has been reported that the high dispersibility of photonic crystals is a property that the refraction angle changes greatly only by slightly changing the wavelength of light, and that the refraction angle can be changed greatly even if the incident angle is changed slightly. (H. Kosaka et al., Rhys. Rev. B 58, R10096 (1998) (Non-patent Document 1)).

  On the other hand, in the case of a photonic crystal formed of a ferroelectric material, the refraction angle can be changed greatly by changing the voltage applied to the photonic crystal even if the wavelength and incident angle of light are fixed. (D. Scrymgeour, N. Malkova, S. Kim and V. Gopalan, Appl. Phys. Lett., 82, 3176 (2003) (non-patent document 2)).

In the optical scanning device of the present embodiment shown in FIGS. 1 and ₂ , the first photonic crystal 12 is formed of TiO ₂ , the second photonic crystal 13 is formed of PLZT, and the second photonic crystal 13 is formed. Since the voltage control unit 14 is connected to the electrodes 131 and 132 formed on the upper and lower surfaces of the nick crystal 13, the laser light 17 emitted from the semiconductor laser 11 and incident on the second photonic crystal 13 is second The voltage applied to the photonic crystal 13 can be controlled to be deflected in an arbitrary direction, and can be incident on the first photonic crystal 12 to increase the deflection angle. Therefore, the voltage can be scanned by controlling the voltage by the voltage controller 14.

  Although the photonic crystal has high wavelength dispersion as described above, the optical scanning position detector 15 detects the scanning start position and the scanning end position and feeds back the signals to the voltage control unit 14, so that the ambient temperature Even if the emission wavelength of the semiconductor laser 11 slightly fluctuates due to changes in the laser beam, the laser beam 17 can be scanned normally.

  In the present embodiment, the first photonic crystal 12 is configured such that only one photonic band for the light (laser light) 17 from the light source (semiconductor laser) 11 exists. Here, the existence of only one photonic band for a certain light means that there is only one propagation state of the light in the photonic crystal. When there are two photonic bands, When two propagation states exist and there is no photonic band, light does not propagate in the photonic crystal (no light exists).

The first photonic crystal 12 of this example has a two-dimensional close-packed circular hole arrangement structure in which circular holes 18 are arranged in close packing in TiO _2. FIG. 3 shows the circular hole radius r and circular holes at that time. FIG. 6 is a band diagram of the TM mode when the ratio r / a to the arrangement interval (lattice constant) a is 0.45.

  In this band diagram, when the normalized frequency is 0.593 (indicated by the broken line in the figure), it can be seen that only band3 exists, and the normalized frequency (ωa / 2πc) is 0.5 according to the wavelength of the light source. The first photonic crystal is formed under the conditions of a lattice constant a such that 593 and r such that r / a is 0.45.

  Specifically, when the light source is red (wavelength 660 nm), the hole radius r is 176.1 nm and the lattice constant a is 391.4 nm. When the light source is green (wavelength 532 nm), the hole radius r is 141. In the case of blue (wavelength 457 nm), the hole radius r is 121.4 nm and the lattice constant a is 271.0 nm.

  FIG. 4 is a diagram showing a dispersion surface in this case, and shows that light incident on the first photonic crystal 12 from the air at θin is deflected to an angle of θp.

  FIG. 5 is a diagram showing the relationship between the incident angle θin and the deflection angle θp, and shows that deflection of 160 ° (+ 80 ° to −80 °) is possible by swinging the incident angle θin by ± 1.7 °. ing.

Even when two photonic bands are present, it is possible to obtain high dispersibility of the photonic crystal. FIG. 6 shows that the ratio r / a between the circular hole radius r and the circular hole arrangement interval (lattice constant) a in a two-dimensional close packed circular hole array structure in which circular holes 18 are arranged in close packing in TiO ₂ is 0. FIG. 25 is a photonic band diagram of the TE mode in the case of .25.

  In the case of this example, when the normalized frequency is 0.425, there are two bands, band 2 and band 3, and in this case, both the dispersion surface of band 2 and the dispersion surface of band 3 exist. (FIG. 7). Even in such a case, if the influence of the band 2 is not affected (the hatched area in FIG. 7), the refraction angle can be greatly changed with a slight deflection of the incident angle. However, the deflection angle that can be continuously changed is less than 120 ° at the maximum, and it is impossible to obtain a deflection angle of 120 ° or more.

  On the other hand, as used in the first photonic crystal of the present embodiment, by using a photonic crystal having only one photonic band, a deflection angle that can be continuously changed by 120 ° or more is obtained. Therefore, the deflection angle widening portion can be reduced, and therefore the entire optical scanning device can be reduced in size.

The two-dimensional photonic crystal 12 of TiO ₂ that is the first photonic crystal is formed by forming a metal mask on the TiO ₂ substrate by an EB lithography process, a metal film deposition process, and a lift-off process, and then performing a dry etching process using a fluorocarbon gas. Can be produced.

  The two-dimensional photonic crystal 13 of PLZT, which is the second photonic crystal, is obtained by pattern-exposing a gel-like photosensitive PLZT film with ultraviolet light, dissolving an unirradiated portion of ultraviolet light with an acidic aqueous solution, and then at 400 ° C. It can be produced by baking with.

In this embodiment, TiO ₂ is used as the dielectric material for forming the first photonic crystal 12, but any other dielectric material may be used as long as it is transparent to the light source wavelength. But it ’s okay.

  Further, although PLZT is used as the ferroelectric material for forming the second photonic crystal 13, any ferroelectric material that is transparent to the light source wavelength may be used. However, PLZT is transparent in the visible light region and has very excellent electro-optical characteristics, and is optimal as a photonic crystal material constituting the optical scanning device of the present invention. Regarding the structure of the photonic crystal, a two-dimensional close-packed hole array structure is used in this embodiment, but other structures may be used.

  In the above embodiment, the scanning start position and the scanning end position are detected by the optical scanning position detector 15 and fed back to the voltage control unit 14, but the scanning position is detected at the scanning start position and the scanning end. For example, as shown in FIG. 8, the laser beam emitted from the photonic crystal 12 is branched by a beam splitter 19 and is always positioned by a position detector 151 in which photodiodes are arranged in an array. May be detected and fed back to the voltage control unit 14.

  Furthermore, a plurality of the optical scanning devices of the present embodiment may be arranged in the main scanning direction or the sub-scanning direction. With the arrangement in which a plurality of optical scanning devices are arranged, the effective scanning speed can be increased.

<Another form of the first embodiment>
An optical scanning device having an antireflection structure will be described with reference to FIGS. 15 and 16 as another form of the first embodiment.
FIG. 15 is a diagram showing a configuration of another form of the optical scanning device of the first embodiment, and FIG. 16 is a top view thereof.

As in the optical scanning device shown in FIG. 1, the optical scanning device shown in FIG. 15 includes a light source (semiconductor laser) 11, a first photonic crystal 12 formed of a dielectric (TiO ₂ ), and a ferroelectric. It comprises a second photonic crystal 13 formed of a body (PLZT), a voltage control unit 14, and an optical scanning position detector (photodiode) 15.

In the first photonic crystal 12 formed of a dielectric (TiO ₂ ), a light-incident surface and a light-exiting surface have a triangular cross-sectional structure with a period of 1/2 or less of the light wavelength. The arranged sawtooth-shaped antireflection structures 31 and 32 are formed.

  Also in the second photonic crystal 13 formed of a ferroelectric (PLZT), the light incident surface and the light emitting surface have a triangular cross-sectional structure with a period of 1/2 or less of the wavelength of the light. The sawtooth-shaped antireflection structures 33 and 34 are formed.

A structure in which pyramid shapes are arranged with a period equal to or less than ½ of the wavelength is referred to as “moth eye” and is known to have an antireflection effect. In the optical scanning device shown in FIG. 15, the light incident surface and the light emitting surface of the first photonic crystal 12 formed of a dielectric (TiO ₂ ), and a second formed of a ferroelectric (PLZT). Since the anti-reflection effect can be obtained even in the sawtooth shapes (31, 32, 33, 34) formed on the light incident surface and the light emitting surface of the photonic crystal 13 of the first photonic crystal 13, the first photonic crystal 12 and the first photonic crystal 13 Unnecessary reflection can be suppressed when the laser light 17 is incident on the second photonic crystal 13 or when the laser light 17 is emitted from the first photonic crystal 12 and the second photonic crystal 13.

  Unnecessary reflections in the scanning optical system not only reduce the amount of light, but also become stray light and cause unnecessary writing on the photosensitive drum, which causes a reduction in image quality of the printer device. However, the configuration shown in FIG. 15 is used. Thus, unnecessary reflection in the scanning optical system can be reduced, and the image quality of the printer apparatus can be improved.

  In the optical scanning device of the present embodiment shown in FIG. 15, the antireflection structure has a sawtooth shape in which a triangular shape is arranged at a half period or less of the wavelength on the entrance surface and the exit surface. An antireflection film made of a film may be formed.

  However, in order to form the antireflection film by the dielectric multilayer film, a process separate from the process of forming the photonic crystal structure is required, whereas in the present embodiment, the triangular shape is less than ½ period of the wavelength. Since it has the arranged sawtooth shape and can be formed at the same time in the process of forming the photonic crystal structure, the manufacturing cost can be suppressed and it can be provided at low cost.

  In addition, the surface forming the sawtooth shape in which the triangular shape is arranged with a period of ½ or less of the wavelength is the surface on which light from the first photonic crystal 12 is incident and the surface from which light is emitted, and the light from the second photonic crystal 13. Any one of the incident surface and the outgoing surface may be used, but the antireflection structure is formed by forming a sawtooth shape in which all the triangular shapes are arranged with a half period or less of the wavelength as in this embodiment. It is desirable to provide

<Second embodiment>
An electrophotographic printer will be described as a second embodiment of the present invention.
FIG. 9 is a configuration diagram of the electrophotographic printer according to the second embodiment.

  The printer shown in FIG. 9 includes the light source (semiconductor laser) 11 described in the first embodiment, the first photonic crystal 12 formed of a dielectric or a ferroelectric, and the first photonic crystal 12 formed of a ferroelectric. 2 photonic crystal 13, voltage controller 14, optical scanning position detector 15, optical scanning device, image carrier (photosensitive drum) 16, charger 20, developer 21, It consists of a transfer device 22 and a fixing device 23.

  In the electrophotographic printer shown in FIG. 9, first, an image carrier (photosensitive drum) 16 is charged by a charger 20, and a laser beam 17 whose intensity is modulated in accordance with image data is scanned by an optical scanning device.

  The region of the image carrier (photosensitive drum) 16 irradiated with the laser beam 17 has a reduced amount of charge, and the amount of charge is related to the reciprocal of the amount of laser beam 17 irradiated. An electrostatic latent image is formed.

  Next, the developing device 21 adsorbs toner to the charged portion on the image carrier (photosensitive drum) 16, and the transfer device 22 applies the toner on the image carrier (photosensitive drum) 16 to the paper surface (transfer paper A). Thereafter, the image carrier (photosensitive drum) 16 is cleaned by the cleaner 24, and the same process is repeated again. Therefore, these steps are sequentially repeated, and finally, the toner on the paper surface is fixed on the paper surface (transfer paper A) by the fixing device 23, whereby an image can be formed on the paper surface (transfer paper A).

<Third embodiment>
A silver salt printer will be described as a third embodiment of the present invention.
FIG. 10 is a configuration diagram of the silver salt printer of the third embodiment.

  The printer shown in FIG. 10 includes the three optical scanning devices described in the first embodiment, a developing device, and a fixing device. In the three optical scanning devices, the light source (R) 111, the light source (G) 112, and the light source (B) 113 have different wavelengths, and are red (R), green (G), and B (blue). The three optical scanning devices are arranged in the sub-scanning direction.

  The operation of the printer shown in FIG. 10 will be described. First, the silver salt paper A1 is sequentially scanned with light of three colors intensity-modulated according to image data by three optical scanning devices to expose the silver salt paper. . Therefore, after that, it is possible to print on the silver salt paper A1 by developing with a developing device, then fixing with a fixing device, and drying.

  In this embodiment, three light scanning devices each using red (R), green (G), and B (blue) as light sources are used. However, by using two or more light scanning devices, Multicolor printing is possible. However, full-color printing is possible by using three or more optical scanning devices having different light source wavelengths. It is necessary to select wavelengths suitable for full-color printing such as red (R), green (G), and B (blue). In addition, the structure of the photonic crystal needs to be changed according to the wavelength of the light source.

  In this embodiment, printing is performed on silver salt paper, but it is also possible to print on a color film or other color recording medium in the same manner.

<Fourth embodiment>
As a fourth embodiment of the present invention, a rewritable paper printer made of a photochromic material will be described.
FIG. 11 is a configuration diagram of the printer of the fourth embodiment.

  The printer shown in FIG. 11 includes the three optical scanning devices described in the first embodiment and an ultraviolet light source (ultraviolet lamp). In the three optical scanning devices, the light source (R) 111, the light source (G) 112, and the light source (B) 113 have different wavelengths, and are red (R), green (G), and B (blue).

  The photochromic material is a material that develops color by irradiation with ultraviolet light and decolors by irradiation with visible light absorbed by the colored material. Three types of photochromic materials were mixed: a yellow material having an absorption spectrum peak near a wavelength of 460 nm, a magenta material having an absorption spectrum peak near a wavelength of 530 nm, and a cyan material having an absorption spectrum peak near a wavelength of 630 nm. For the material coated on the white film, after all materials are colored by UV irradiation, the cyan material is decolored and red when irradiated with red light, and the magenta material is decolored when irradiated with green light. Thus, the green color is displayed, and the portion irradiated with the blue light is decolored by the yellow material to display blue, and a full color image can be displayed.

  In addition, when irradiated again with ultraviolet light, all the materials are colored and the image can be erased, so it can be used as a rewritable paper that can be rewritten repeatedly (Ikue Kawashima, Hiroyuki Takahashi, Narunobu Hirano, Optics Vol. 32, No. 12, 707 (2003) (non-patent document 3)).

  A photochromic material is used as a rewritable paper that can be rewritten repeatedly because it can be erased when irradiated with ultraviolet light and irradiated with light of a certain color. Can do.

  The operation of the printer shown in FIG. 11 will be described. First, rewritable paper (photochromic paper A2) made of a photochromic material is irradiated with ultraviolet light with an ultraviolet light source to erase an already formed image.

  Next, the erased rewritable paper (photochromic paper A2) is printed on the rewritable paper (photochromic paper A2) by sequentially scanning light of three colors intensity-modulated in accordance with image data with three optical scanning devices. Can do.

  In the present embodiment, three light scanning devices each using red (R), green (G), and B (blue) as light sources are used. However, as in the third embodiment, two or more are used. By using this optical scanning device, multicolor printing can be performed.

  However, full-color printing is possible by using three or more optical scanning devices having different light source wavelengths. It is necessary to select wavelengths suitable for full-color printing such as red (R), green (G), and B (blue). In addition, the structure of the photonic crystal needs to be changed according to the wavelength of the light source.

It is a figure which shows the structure of the optical scanning device based on a 1st Example. FIG. 2 is a top view of the optical scanning device shown in FIG. 1. In the first embodiment, the hole radius r and the hole arrangement interval (lattice constant) of the first photonic crystal in a two-dimensional close-packed hole arrangement structure in which holes are arranged in close packing in TiO ₂ It is a band figure of TM mode in case ratio r / a with a is 0.45. It is a figure which shows the dispersion surface in a 1st Example. It is a figure which shows the relationship between incident angle (theta) in and deflection | deviation angle (theta) p in a 1st Example. In the first embodiment, the hole radius r and the hole arrangement interval (lattice constant) of the first photonic crystal in a two-dimensional close-packed hole arrangement structure in which holes are arranged in close packing in TiO ₂ It is a photonic band figure of TE mode when ratio r / a with a is 0.25. In a 1st Example, it is a figure which shows the dispersion surface of band 2 and the dispersion surface of band 3 when a normalization frequency is 0.425. It is a figure which shows the modification of the optical scanning device in a 1st Example. It is a block diagram of the electrophotographic printer which concerns on a 2nd Example. It is a block diagram of the silver salt system printer of the 3rd Example. FIG. 10 is a configuration diagram of a printer according to a fourth embodiment. It is a figure for demonstrating the polygon mirror system disclosed by Unexamined-Japanese-Patent No. 2003-202510 (patent document 1). It is a figure for demonstrating the optical scanning device disclosed by Unexamined-Japanese-Patent No. 9-226172 (patent document 2). It is a figure for demonstrating the optical scanning device proposed by Unexamined-Japanese-Patent No. 2001-13439 (patent document 3). It is a figure which shows the structure of the optical scanning device of another form of a 1st Example. FIG. 16 is a top view of the optical scanning device shown in FIG. 15.

Explanation of symbols

11, 111, 112, 113: Light source (semiconductor laser)
12: First photonic crystal (TiO ₂ )
13: Second photonic crystal (ferroelectric (PLZT))
131, 132: Electrodes 14, 141, 142, 143: Voltage controller 15, 1511: Optical scanning position detector 16: Image carrier (photosensitive drum)
17: Laser light 18: Circular hole 20: Charger 21: Developing device 22: Transfer device 23: Fixing device 24: Cleaner 25: Lens 26: Transfer roller 27: Ultraviolet light source (ultraviolet lamp)
31, 32, 33, 34: Sawtooth-shaped antireflection structure A: Transfer paper A1: Silver salt paper A2: Photochromic paper 202: Polygon mirror 222: Spherical lens (first scanning lens)
226: Toric lens (second scanning lens)
227: Photosensitive drum (photoconductor)
230: Photodetector 232: Cylindrical lens 251: Light source means 252: Collimator lens 253: Aperture 255: Parallel flat glass 308: Glass substrate 309: Signal electrode 310: First contact hole of insulating film 311: Transparent electrode 312: Insulation Second contact hole of film 313: Hole transport layer 314: Light emitting layer 315: Electron injection electrode 316: First contact hole of protective film 317: Second contact hole of protective film 318: Common electrode 410: Wavelength tunable laser 430: Photonic crystal 431: Silicon oxide film 432: Cylindrical silicon

Claims (16)

A light source, a deflector that deflects light from the light source, a deflection angle expander that expands a deflection angle of the light deflected by the deflector, and a detector that detects a scanning position,
The deflector includes a photonic crystal formed of a ferroelectric and a voltage control unit that controls a voltage applied to the photonic crystal formed of the ferroelectric.
The deflection magnifier is made of a photonic crystal formed of a ferroelectric or a dielectric, and at least in the photonic crystal forming the deflection magnifier, there is only one photonic band for light from a light source. An optical scanning device characterized by the above.   2. The optical scanning device according to claim 1, wherein a detection signal of a scanning position detected by the detector is fed back to a voltage control unit that controls a voltage applied to a photonic crystal formed of a ferroelectric material of the deflector. And scanning the light. The optical scanning device according to claim 1 or 2,
Antireflection on either the light incident surface and the light emitting surface of the ferroelectric photonic crystal constituting the deflector, or the light incident surface and the light emitting surface. An optical scanning device comprising means. The optical scanning device according to claim 3.
The optical reflection apparatus is characterized in that the antireflection means is a structure in which a cross section of a triangular shape is arranged with a period of 1/2 or less of a light source wavelength. The optical scanning device according to claim 4.
An optical scanning device characterized in that formation of a photonic crystal constituting the deflector and arrangement of a structure having a triangular cross section are performed in the same process. In the optical scanning device according to any one of claims 1 to 5,
Either the light incident surface and the light emitting surface of the ferroelectric or dielectric photonic crystal constituting the deflection angle expander, or the light incident surface and the light emitting surface An optical scanning device characterized in that an antireflection means is provided on the surface. The optical scanning device according to claim 6.
An optical scanning device characterized in that the antireflection means arranges a structure having a triangular cross section with a period of 1/2 or less of a light source wavelength. The optical scanning device according to claim 7.
An optical scanning device characterized in that formation of a photonic crystal constituting the deflection angle expander and arrangement of a structure having a triangular cross section are performed in the same process.   9. An optical scanning device comprising at least two optical scanning devices according to claim 1 arranged in the main scanning direction.   9. An optical scanning device comprising at least two optical scanning devices according to claim 1 arranged in the sub-scanning direction.   The optical scanning device according to claim 10, wherein the light source wavelengths of two or more optical scanning devices arranged in the sub-scanning direction are at least two.   9. An optical scanning device according to claim 1, wherein at least three optical scanning devices according to claim 1 are arranged in the sub-scanning direction, and at least three light source wavelengths are provided.   13. The optical scanning device according to claim 1, wherein the ferroelectric material forming the photonic crystal is PLZT.   The optical scanning device according to claim 1, an image carrier on which an electrostatic latent image is formed by light from the optical scanning device, and developing the electrostatic latent image on the image carrier A printer comprising: a developing unit; a transfer unit that transfers a developed image onto a transfer sheet; and a fixing unit that fixes the image transferred onto the transfer sheet.   13. An optical scanning device according to claim 12, a developing device for developing an image formed on a silver salt type recording medium by light from the optical scanning device, and a fixing device for fixing the developed image. A printer characterized by that.   14. A printer comprising: the optical scanning device according to claim 1; and an ultraviolet light source that generates ultraviolet light for erasing an image.

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