JP2007114472A - Optical addressing spatial optical modulator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To modulate the external light in a higher contrast without producing cross talk between the color images regardless of the kinds of the light sources for writing. <P>SOLUTION: This optical addressing spatial optical modulator is built by stacking several optical addressing spatial optical modulator layers having at least a liquid crystal layer to reflect outdoor light and a photoconducting layer changing its resistance depending on the intensity of the incident light. The above photoconducting layers have wave absorption regions different from each other, and the above liquid crystal layer reflects the irradiated outdoor light of the wavelength regions different from each other. Further, it has an optical function layer to interrupt the incident light of the wavelength regions overlapping each other in the wave absorption regions of this and other photoconducting layers, at least at the position receiving the above incident light on the incident side of the photoconducting layer. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an optical address type spatial light modulator.

  Optical addressing type spatial light modulation elements are being studied for application to optical amplification elements for projection displays, optical computing elements for optical computing, or display elements that themselves are used as media.

FIG. 7 is a diagram showing a conventionally used optical address type spatial light modulator (see, for example, Patent Document 1).
In FIG. 7, an optical address type spatial light modulator 1 includes three optical address type optical modulation layers (hereinafter referred to as “optical modulation layers”) that modulate different colors of light (R, G, B) in the readout light. In some cases, 3A, 3B, and 3C are stacked. In the optical addressing type light modulation layer 3A, the writing light 15 is emitted from the surface side from which the reading light 16 is emitted between the substrate 4A having the electrode 6A on the inner surface and the substrate 5A having the electrode 7A on the inner surface. The cholesteric (chiral nematic) liquid crystal layer 8A that selectively reflects B (blue) color light, the Y color light absorption layer 10A that absorbs B color light, and the B color light are absorbed in order toward the back surface side. A photoconductive layer 9A in which a Y (yellow) color charge generation layer and a photoconductive layer are stacked is stacked.

  In addition, the optical addressing type light modulation layer 3B includes G (green) in order from the front side to the back side between the substrate 4B having the electrode 6B on the inner surface and the substrate 5B having the electrode 7B on the inner surface. Cholesteric (chiral nematic) liquid crystal layer 8B that selectively reflects color light, M (magenta) light absorption layer 10B that absorbs G light, and M charge generation layer and light that absorb G light Photoconductive layers 9B each having a conductive layer stacked thereon are stacked.

  Further, the optical addressing type light modulation layer 3C is similarly formed in order of R (from the front surface side to the back surface side) between the substrate 4C provided with the electrode 6C on the inner surface and the substrate 5C provided with the electrode 7C on the inner surface. A cholesteric (chiral nematic) liquid crystal layer 8C that selectively reflects red light, a C light absorption layer 10C that absorbs R light, and a C charge generation layer that absorbs R light A photoconductive layer 9C in which a photoconductive layer and a photoconductive layer are stacked is stacked. The substrates 5A and 4B may be the same substrate, and the thickness of the medium can be reduced, and moreover, optical loss is small, which is more preferable. The same is preferable for 5B and 4C.

This optical address type spatial light modulator 1 can be written and read by connecting to the writing unit 2.
The writing unit 2 includes a voltage applying unit 11 that applies bias voltages 14A, 14B, and 14C between the electrodes 6A and 7A, between 6B and 7B, and between 6C and 7C of each of the optical addressing type optical modulation layers 3A, 3B, and 3C. The light irradiation unit 13 irradiates the modulated address light 15 to the optical address type spatial light modulation element 1, and the voltage application unit 11 and the control unit 12 that controls the light irradiation unit 13.

  With the above configuration, the writing light 15A is incident on the photoconductive layer 9A of the photoaddressable light modulation layer 3A without being absorbed by the photoaddressable light modulation layers 3B and 3C, and the photoconductive layer 9A and the light absorption layer. Absorbed by 10A, light leakage to the liquid crystal layer 8A side is prevented. Further, the writing light 15B is incident on the photoconductive layer 9B of the photoaddressable light modulation layer 3B without being absorbed by the photoaddressable light modulation layer 3C, and is absorbed by the photoconductive layer 9B and the light absorption layer 10B. , Light leakage to the liquid crystal layer 8B side is prevented. Further, the writing light 15C is incident on the photoconductive layer 9C of the optical address type light modulation layer 3C and is absorbed by the photoconductive layer 9C and the light absorption layer 10C, thereby preventing light leakage to the liquid crystal layer 8C side.

  On the other hand, the readout light 16C is incident on the liquid crystal layer 8C of the optical addressing type optical modulation layer 3C without being absorbed by the optical addressing type optical modulation layers 3A and 3B, and is moved toward the photoconductive layer 9A by the optical absorption layer 10C. The reading light 16B is incident on the liquid crystal layer 8B of the optical addressing optical modulation layer 3B without being absorbed by the optical addressing optical modulation layer 3A, and the photoconductive layer 9B is absorbed by the optical absorption layer 10B. The reading light 16A is incident on the liquid crystal layer 8A of the optical address type light modulation layer 3A, and the light absorption layer 10A prevents light leakage to the photoconductive layer 9C side.

In this way, even in a structure in which a plurality of optical address type optical modulation layers are stacked, write light for operating each optical address type optical modulation layer and read light modulated by each optical address type optical modulation layer It is possible to individually control the optical state of each optical address type optical modulation layer without considering mutual interference.
JP 2003-140184 A

  However, in the conventional optical address type spatial light modulation element shown in FIG. 7, the absorption spectrum of the photoconductive layer of each light modulation layer is actually broad, so that the address light in the wavelength region where the absorption overlaps. In contrast, crosstalk (mixed color generated by absorbing light in the adjacent absorption wavelength region unintended by the photoconductive layer) occurs between each color image, and an incorrect optical address due to address light of other colors Operation may occur.

  For this reason, the light source used for the writing light is limited to a light source that emits single-wavelength light such as an LED or a laser, which not only increases the cost but also limits the application range as a light modulation element. There was a problem.

The object of the present invention is to solve the above-mentioned problems of the prior art.
That is, the present invention provides an optical address type spatial light modulator capable of modulating external light with higher contrast without causing crosstalk between color images regardless of the type of light source of writing light. The purpose is to do.

The above-mentioned subject is achieved by the following present invention. That is, the present invention
<1> A liquid crystal layer that reflects external light in a specific wavelength range irradiated from the front surface side, and a resistance value according to the intensity of the absorbed incident light that absorbs incident light in the specific wavelength range irradiated from the back surface side. A plurality of photo-addressable light modulation layers, at least laminated with a photoconductive layer that changes
Each photoconductive layer constituting the plurality of photoaddressable light modulation layers has a different absorption wavelength range, and each photoconductive layer absorbs incidents in different wavelength ranges irradiated from the back side. The liquid crystal layer corresponding to each of the photoconductive layers whose resistance has changed is an optical address type spatial light modulator that reflects external light in different wavelength ranges irradiated from the surface side,
The incident light in the wavelength region where absorption is overlapped in the absorption wavelength region of the photoconductive layer and the absorption wavelength region of another photoconductive layer is blocked at least on the incident light side of the photoconductive layer irradiated with the incident light. An optically addressed spatial light modulation device including an optical functional layer.

<2> The optical address type spatial light modulator according to <1>, wherein an absolute value of a difference in absorptance in a wavelength region where absorption is mutually overlapped is 50% or less.

<3> The optical address type spatial light modulator according to <1>, wherein the optical functional layer includes only one layer.

<4> The optical address type spatial light modulator according to <1>, wherein the optical functional layer includes a plurality of layers.

  According to the present invention, there is provided an optical address type spatial light modulator capable of modulating external light with higher contrast without causing crosstalk between color images regardless of the type of light source of writing light. can do.

Hereinafter, the present invention will be described in detail.
The optical address type spatial light modulator of the present invention absorbs and absorbs a liquid crystal layer that reflects external light in a specific wavelength region irradiated from the front surface side and incident light in the specific wavelength region irradiated from the back surface side. Each of the photoconductive layers constituting the plurality of photoaddressable light modulation layers is formed by laminating a plurality of photoaddressable light modulation layers at least laminated with a photoconductive layer that changes the resistance value according to the intensity of incident light. The layers have different absorption wavelength ranges, and each photoconductive layer absorbs incident light in different wavelength ranges irradiated from the back side and changes in resistance. The corresponding liquid crystal layer is a photoaddressable spatial light modulator that reflects external light in different wavelength ranges irradiated from the surface side, and at least incident light of the photoconductive layer irradiated with the incident light The absorption wavelength range of the photoconductive layer at the position on the side The absolute value of the difference in absorptivity of the mutual absorption overlap portions in the absorption wavelength range of fine other photoconductive layer, characterized in that it comprises an optical functional layer that blocks incident light in a wavelength range of 50% or less.

  As described above, in an optically addressed spatial light modulation device in which a light modulation layer having a photoconductive layer is laminated, the absorption spectrum of the photoconductive layer in each light modulation layer is broad in practical use, so that the wavelength at which the absorption overlaps For area address light (incident light), crosstalk occurs between the color images, and an erroneous optical address operation due to address light of other colors may occur.

  Specifically, for example, FIG. 2 shows an absorption spectrum of an organic photoconductor (OPC) as a photoconductive layer used for two light modulation layers to be laminated. In the wavelength band B, the light absorption of both OPC1 and OPC2 overlaps with a high absorption rate. Therefore, when a light modulation layer having both the photoconductive layers is laminated, both photoconductive layers are formed in the wavelength band A and the wavelength band B. The visible light from the back side is absorbed, and the reflectance of the liquid crystal layer is increased accordingly. As a result, the display color of the reflected image deviates from the address light.

  As a result of intensive studies on the above problems, the present inventors have determined that out of incident light (writing light) in a specific wavelength region irradiated from the back side of the optical address type spatial light modulator in order to suppress the occurrence of the crosstalk. It is effective to provide an optical functional layer that blocks incident light in a wavelength region where the light absorption rate of both of the absorption wavelength region of the photoconductive layer and the absorption wavelength region of the other photoconductive layer overlaps each other. I found out.

  FIG. 3 schematically shows the principle and operation of the present invention. FIG. 3 schematically shows an emission spectrum of incident light before and after being transmitted through the optical functional layer 20. The lower side of the optical functional layer 20 in the figure is emission spectra of blue light 22, green light 24, and red light 26 based on a certain light source, and these include a C region that is a wavelength region in which light emission overlaps due to the wavelength distribution of the light source. , D region exists. When the C region and the D region overlap with the A wavelength region and the B wavelength region in FIG. 2, both the OPC1 and the OPC2 cause light absorption beyond a certain level due to the light in this portion. Causes the occurrence.

  Therefore, as shown in FIG. 3, an optical functional layer 20 that blocks (cuts) the light in the C region and the D region is prepared, and through this, the blue light 22, the green light 24, and the red light 26 are more Blue light 22 ′, green light 24 ′, and red light 26 ′ having sharp emission spectra can be obtained, and light that reacts only with the target photoconductive layer can be generated, so that occurrence of crosstalk can be prevented.

  In this case, the mutually overlapping wavelength region means, for example, a portion where two absorption wavelength regions overlap each other. For example, when three or more absorption wavelength regions overlap each other, the two absorption regions to be compared with each other are compared. The overlapping part of wavelength regions.

  In the present invention, it is preferable to use an optical functional layer that blocks incident light in a wavelength range in which the absolute value of the difference in absorptivity in the wavelength range where the absorption wavelength ranges overlap with each other is 50% or less. Here, the absolute value of the difference in the absorptance in the wavelength region where the absorption wavelength region overlaps refers to the contrast of the absorptance to be compared, but when this contrast exceeds 50%, it is compared in that wavelength region. Since the intensity of light absorbed by the photoconductive layer varies greatly, crosstalk does not occur.

  In the present invention, as described above, the difference between the absolute values of the absorptance is preferably 50% or less, and more preferably 75% or less.

  Here, the absorptance is a ratio of light intensity absorbed by the photoconductive layer to light incident on the light modulation layer.

The optical address type spatial light modulator of the present invention will be described below with reference to the drawings.
FIG. 1 is a schematic view showing an example of an optical address type spatial light modulator of the present invention. FIG. 1 shows an embodiment in which a light modulation layer 46A including two liquid crystal layers 38A and 38B and a light modulation layer 46B including one liquid crystal layer 38C are combined. The light modulation layer 46A includes liquid crystal layers 38A and 38B, light-shielding layers 37A and 37B, and photoconductive layers that reflect readout light 42A and 42B, respectively, between substrates 33A and 34A on which transparent electrodes 35A and 36A are formed. 43A is laminated.
The light modulation layer 46B includes a liquid crystal layer 38C, a light shielding layer 37C, and a photoconductive layer 43B that reflect the readout light 42C between the substrates 33B and 34B on which the electrodes 35B and 36B are formed. An optical functional layer 50 is laminated between the conductive layer 43B.

  The writing device (writing unit) 32 used for the optical address type spatial light modulation element applies a bias voltage 41A between the electrodes 35A and 36A of the light modulation layer 46A and also biases between the electrodes 35B and 36B of the light modulation layer 46B. A voltage application unit 40 that applies a voltage 41B, and a light irradiation unit 44 that irradiates the photoconductive layer 43A of the light modulation layer 46A with the write light 45A and irradiates the photoconductive layer 43B of the light modulation layer 46B with the write light 45B; The control unit 39 controls the voltage application unit 40 and the light irradiation unit 44 in accordance with a predetermined light modulation pattern.

  The substrates 33 and 34 are formed using glass, silicon, or a polymer film such as polyester such as polyethylene terephthalate (PET), polysulfone, polyethersulfone, or polycarbonate, and are at least on the back side from the substrates 33A and 33B. It is transparent to the readout light reflected by the liquid crystal layers 38A, 38B and 38C of the optical address type light modulation layers 46A and 46B, and is absorbed by the photoconductive layers 43A and 43B on the surface side of the substrates 34A and 34B. It is configured so as to be transparent to the writing light. Moreover, you may form well-known functional films, such as a liquid-crystal aligning layer, an abrasion-resistant layer, and the barrier layer which prevents mixing of gas, as needed.

  The electrodes 35 and 36 are formed using an ITO film, a NESA film, or the like, and are reflected by the liquid crystal layers 38A, 38B, and 38C of the optical addressing type light modulation layers 46A and 46B that are at least on the back side of the electrodes 35A and 35B. The reading light is transparent, and the writing light absorbed by the photoconductive layers 43A and 43B on the surface side of the electrodes 35B and 36B is transparent. .

The liquid crystal layer 38 can control the reflectance or absorption rate of light in a specific wavelength region. As the liquid crystal, nematic liquid crystal, chiral nematic liquid crystal, smectic A liquid crystal, chiral smectic liquid crystal, discotic liquid crystal, or the like can be used.
Further, by using a memory liquid crystal such as a chiral nematic liquid crystal, a surface-stabilized chiral smectic C liquid crystal, a bistable twisted nematic liquid crystal, or a fine particle dispersed liquid crystal, the light modulation element of the present invention can be used as an optical recording medium or an image recording medium. can do. Here, a cholesteric (chiral nematic) liquid crystal that reflects visible light in a specific wavelength range is used.

  As liquid crystal materials, known liquid crystal compositions such as cyanobiphenyl, phenylcyclohexyl, phenylbenzoate, cyclohexylbenzoate, azomethine, azobenzene, pyrimidine, dioxane, cyclohexylcyclohexane, stilbene, and tolan are used. it can. Additives such as dyes such as dichroic dyes and fine particles may be added to the liquid crystal material, and those dispersed in a polymer matrix, polymer gels, and microcapsules may be used. The liquid crystal may be a polymer, medium molecule, or low molecule, or a mixture thereof.

The photoconductive layer 43 is formed of an inorganic photoconductor such as a-Si: H, a-Se, Te-Se, As ₂ Se ₃ , CdSe, CdS, or an azo pigment, phthalocyanine pigment, perylene pigment, quinacridone pigment, pyrrolopyrrole. It is composed of an organic photoconductor (OPC) that combines a charge generation material such as a pigment or an indigo pigment and a charge transport material such as arylamine, hydrazone, triphenylmethane, or PVK.

  The light shielding layer 37 is made of a material that absorbs light from an external light source, incident light, light having the wavelength of external light, and the like, and has a high electrical resistance. Resin color materials such as dyed resin can be used.

The optical density required for the light-shielding layer 37 depends on the sensitivity of the photoconductive layer 43 and the intensity of external light, but cannot be defined unconditionally, but is preferably at least 1 or more, more preferably 2 or more. Further, it is desirable that the electrical resistance of the light shielding layer 37 is at least 10 ⁸ Ω · cm in terms of volume resistivity so as not to cause a reduction in resolution due to a current in the light shielding layer. Furthermore, in order to increase the change in the partial pressure applied to the liquid crystal layer 38, the larger the capacitance of the light shielding layer 37, the better. Therefore, it is preferable that the dielectric constant is large and the film thickness is small.

  As described above, the optical functional layer 50 in the present invention is provided in order to block incident light in a wavelength region where the absorption wavelength region overlaps between the plurality of organic photoreceptor layers 43. In FIG. 1, only one layer is provided on the back surface side of the photoconductive layer 43B closest to the light irradiation unit 44 in order to block the overlapping wavelength region of the two photoconductive layers 43A and 43B. The number of the optical functional layers 50 in the present invention is not particularly limited, and the positions provided are not limited.

  In other words, in the present invention, the optical functional layer 50 may be provided at least on the incident light side of the required photoconductive layer, and may be provided on the incident light side of the photoconductive layer 43A, for example, depending on the wavelength range to be cut. Alternatively, a plurality of layers may be provided one by one on the incident light side of the photoconductive layers 43A and 43B. Further, a plurality of optical function layers having different shielding wavelength ranges may be provided in one place.

The optical functional layer 50 is formed of, for example, a coating layer in which a pigment or dye having a desired absorption region is dispersed in a resin, as in a normal light absorption layer.
Examples of pigments include cadmium, chromium, cobalt, manganese, carbon and other inorganic pigments, azo, anthraquinone, indigo, triphenylmethane, nitro, phthalocyanine, perylene, pyrrolopyrrole, Organic pigments such as quinacridone, polycyclic quinone, squalium, azurenium, cyanine, pyrylium, and anthrone can be used.

  As dyes, nitroso dyes, nitro dyes, azo dyes, stilbene azo dyes, diphenylmethane dyes, triphenylmethane dyes, xanthene dyes, acridine dyes, quinoline dyes, polymethine dyes, thiazole dyes, indophenol dyes, azine dyes, oxazine dyes, thiazines Dyes, sulfur dyes, aminoketone dyes, anthraquinone dyes, indigoid dyes and the like can be used.

Among these, for example, when cutting light in a wavelength range of 520 to 550 nm, a quinacridone system is preferably used.
Moreover, when cut | disconnecting a several wavelength range, it is good also as a several optical functional layer which mix | blended the said pigment etc. separately, and it is good also as a single optical functional layer by mixing a several pigment.

  Resins include alkyd (phthalic acid) resin, vinyl chloride resin, vinylidene chloride resin, unsaturated polyester resin, melamine resin, urea resin, phenol resin, acrylic resin, polyurethane resin, vinyl acetate resin, epoxy resin, cellulose, silicone resin, Resins such as butyral resin can be used. You may include additives, such as hardening | curing agents, such as polyisocyanate, and a thickener.

  In the present invention, the mass ratio (pigment / resin) between the pigment and the resin in the optical functional layer is preferably in the range of 20/80 to 40/60, and is preferably in the range of 25/75 to 35/65. It is more preferable.

  The optical functional layer 50 is formed by applying the pigment and the resin in the form of an aqueous or organic paint by a coating method such as roll coating, spin coating, bar coating, dip coating, die coating, gravure printing, flexographic printing, or screen printing. Can be made.

  As a specific method for producing the optical functional layer 50 in the present invention, first, the absorption spectrum of the photoconductive layer to be compared is measured as shown in FIG. 2, and then the contrast between them (absolute value of the difference in absorption rate) is measured. And a wavelength region in which this is preferably 50% or less is determined. Next, a specific pigment having an absorption region in this wavelength region is selected to produce an optical functional layer by the above method, and the transmittance in the wavelength region is preferably 50% or less, more preferably 40% or less. Thus, the pigment / resin ratio, film thickness, etc. are determined.

  On the other hand, in the optical functional layer 50, it is preferable to increase the transmittance as much as possible in a region other than the wavelength region where the light is cut. Specifically, the average transmittance (in the range of 400 to 800 nm) outside the wavelength range to be cut is preferably 80% or more.

  The layer thickness of the optical functional layer 50 in the present invention is preferably in the range of 0.1 to 20 μm, more preferably in the range of 0.1 to 1.5 μm.

  With this configuration, for example, when the writing light 45A is blue light and 45B is red light, each color light of blue as reading light 42A, green as 42B, and red as 42C can be read. A color image can be displayed in response to light irradiation.

  That is, the drive of the optical address type spatial light modulation device of the present invention shown in FIG. , 41B, and write light 45A, 45B having an intensity in consideration of the photosensitivity of the photoconductive layers 43A, 43B from the light irradiation unit 44 to change the optical state of the liquid crystal layer. The reflection states of 42A, 42B, and 42C are changed. The timing of applying the bias voltages 41A and 41B and the timing of irradiating the read lights 42A, 42B, and 42C are determined by the combinations 41A and 41A of the bias voltage and the write intensity required for the operation of each of the optical addressing optical modulation layers 46A and 46B Adjustment is performed by the control unit 39 so that 45A, 41B and 45B overlap at least partially.

  In the optical address type optical modulation element shown in FIG. 1, writing lights 45A and 45B carrying an image are incident from the back side. The photoconductive layers 43A and 43B constituting the respective optical addressing type light modulation layers 46A and 46B absorb incident light in different wavelength ranges, and transmit incident light in wavelength ranges other than the absorbing wavelength range. When the photoconductive layer 43A absorbs the B color (blue), the resistance value decreases, but the G color (green) and R color (red) light is transmitted, so that the resistance value is not obtained for the G color and R color light. Does not change. Further, when the photoconductive layer 43B absorbs R-color light, the resistance value decreases, but B-color light and G-color light are transmitted. Therefore, the resistance value does not change for B-color light and G-color light.

  As the resistance value of each photoconductive layer 43A, 43B decreases, the partial pressure applied to each liquid crystal layer 38A, 38B, 38C increases, and the color light absorbed by each photoconductive layer 43A, 43B increases. The reflectance with respect to the wavelength region is increased. That is, the B color of the readout light (external light) has a higher reflectance in the wavelength region of the B color light due to the write light of the B color light in the optical address type spatial light modulation layer 46A. Reflected by the liquid crystal layer 38A. In addition, the G light of the readout light is transmitted from the liquid crystal layer 38B in the optical address type spatial light modulation layer 46A, which has a higher reflectance in the wavelength range of the G light due to the B light write light. reflect. Further, the R light in the readout light is transmitted through the optical addressing light modulation layer 46A, and in the wavelength region of the R light by the R writing light in the optical addressing light modulation layer 46B. The light is reflected by the liquid crystal layer 38C having a high reflectance, and is again transmitted through the optical address type light modulation layer 46A.

  In this optical addressing type optical modulation element, writing light 45A, 45B carrying an image is incident from the back side to write an image, and reading light 42A, 42B, 42C for image reading is similarly incident from the front side. An image is read on the front side.

The light irradiation unit 44 may be any device that can irradiate the light modulation unit 31 with writing light 45A and 45B of arbitrary intensity, and is a self-luminous element such as a laser beam scanning device, LED array, CRT display, plasma display, or EL display. There is no particular limitation such as a combination of a light control device such as a liquid crystal shutter and a light source such as a fluorescent tube, a xenon lamp, a halogen lamp, a mercury lamp, or an LED lamp.
In the present invention, since the optical functional layer is provided as described above, it is not necessary to use monochromatic light such as laser light as a light source.

<Test example>
In order to confirm the effect of the optical address type spatial light modulator of the present invention as described above, the following test was performed. Specifically, it was examined how much the absorption contrast changes depending on the presence or absence of an optical functional layer for two photoconductive layers for producing a photoaddressable spatial light modulator as shown in FIG.

(Preparation of photoconductive layer)
Two photoconductive layers (organic photoconductor layer (OPC layer)) used for this were produced on the premise of producing a photoaddressable spatial light modulator as shown in FIG. For simplicity, the photoconductive layer 43A in FIG. 1 is a red OPC layer that absorbs cyan, and the photoconductive layer 43B is a blue OPC layer that absorbs red light.

-Red OPC layer-
200 nm of a solution in which dibromoanthanthrone pigment or anthrone pigment having high sensitivity to visible light of 600 nm or less is dispersed in polyvinyl butyral on a 0.125 mm thick PET substrate on which an ITO transparent electrode is patterned using tetrahydrofuran as a solvent. A thick spin coat was applied, and N, N′-bis (3-methylphenyl) -1,1′-biphenyl-4,4′-diamine was dispersed in bisphenol Z polycarbonate using monochlorobenzene as a solvent. A red OPC layer was formed by bar coating the solution to a thickness of 3 μm.

  When the absorption spectrum of this red OPC layer was measured with a spectrophotometer, the same absorption spectrum as that of OPC2 in FIG. 2 was obtained.

-Blue OPC layer-
On a 0.125 mm thick PET substrate with a patterned ITO transparent electrode, a solution in which titanyl phthalocyanine pigment with high sensitivity to visible light of 600 nm or more is dispersed in polyvinyl butyral using butanol as a solvent is spin coated to a thickness of 200 nm. On top of that, a solution in which N, N′-bis (3-methylphenyl) -1,1′-biphenyl-4,4′-diamine is dispersed in bisphenol Z polycarbonate using monochlorobenzene as a solvent is made 3 μm thick. A blue OPC layer was formed by applying a bar coat.

When the absorption spectrum of this blue OPC layer was measured with a spectrophotometer, the same absorption spectrum as that of OPC1 in FIG. 2 was obtained.
A contrast curve (difference curve) between the absorption spectrum and the absorption spectrum of the red OPC layer was obtained, and a wavelength region where the contrast (absolute value of the difference in the absorptivity of the overlapping portion) was 50% or less was obtained. However, it was the range of 535-570 nm.

(Production of optical functional layer)
30 parts by mass of magenta pigment (quinacridone) and 70 parts by mass of polyvinyl alcohol resin were dispersed in water to obtain an optical functional layer forming liquid. This was spin-coated on a 0.125 mm thick PET substrate to form a 1.3 μm thick optical functional layer.

  When the transmittance of this optical functional layer was measured with a spectrophotometer in the same manner as described above, a transmission spectrum as shown in FIG. 4 was obtained. From this transmission spectrum, the wavelength region where the transmittance was 50% or less was 510 to 570 nm.

(Confirmation of effects when using optical functional layer)
-Test Example 1
As a light source, a cell phone liquid crystal display (SH901iC, manufactured by NTT Docomo) was used. The emission spectra of blue light and red light of this light source are shown in FIGS. 5 (A) and 5 (B), respectively.

Each absorptance (%) of the red OPC layer and the blue OPC layer with respect to the blue light was measured in a wavelength range of 400 to 700 nm by an instantaneous multi-photometry system (MC2530, manufactured by Otsuka Electronics Co., Ltd.). Similarly, each absorptance (%) of the red OPC layer and the blue OPC layer with respect to the red light was also measured.
Next, the optical function layer was disposed on the incident light surface of each OPC layer, and the same measurement was performed.

As a result, the ratio of the absorption rate of the red OPC layer to the absorption rate of the blue OPC layer with respect to blue light (red OPC layer / blue OPC layer) was 1.4 before the insertion of the optical functional layer, but after the insertion, Raised to 1.5.
In addition, the ratio of the absorption rate of the blue OPC layer to the absorption rate of the red OPC layer with respect to red light (blue OPC layer / red OPC layer) was 43.5 before the insertion of the optical function layer, but 50 after the insertion. It rose to .9.

-Test Example 2-
The optical functional layer was prepared in the same manner as in Test Example 1 except that the red OPC layer and the blue OPC layer prepared in Test Example 1 were used and a notebook personal computer liquid crystal display (manufactured by NEC, VersaPro) was used as the light source lamp. The effect when using was confirmed.
The emission spectra of blue light and red light of this light source are shown in FIGS. 6 (A) and 6 (B), respectively.

As a result, the ratio of the absorption rate of the red OPC layer to that of the blue light and the absorption rate of the blue OPC layer (red OPC layer / blue OPC layer) was 1.0 before the insertion of the optical functional layer, but after the insertion, Rose to 1.1.
Further, the ratio of the absorption rate of the blue OPC layer to that of the red OPC layer and the absorption rate of the red OPC layer (blue OPC layer / red OPC layer) was 21.7 before the insertion of the optical functional layer, but 25 after the insertion. Rose to .6.

  From the above results, when any general-purpose light source is used, the contrast between the red OPC layer and the blue OPC layer with respect to red light and blue light is increased by passing through the optical functional layer. It was suggested that crosstalk in the optical address type spatial light modulator can be eliminated even when the absorption regions overlap.

It is the schematic which shows an example of the optical address type | mold spatial light modulation element of this invention. It is a figure which shows an example of the absorption spectrum of OPC to contrast. It is a schematic diagram which shows the effect | action by the optical function layer in this invention. It is a figure which shows the transmission spectrum of the optical function layer used in the Example. It is a figure which shows the emission spectrum based on the light source used in the Example, (A) is about blue light, (B) is about red light. It is a figure which shows the emission spectrum based on the other light source used in the Example, (A) is about blue light, (B) is about red light. It is the schematic which shows an example of the conventional optical address type | mold spatial light modulation element.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,31 Light modulation part 2,32 Writing part apparatus 3,46 Light modulation layer 4,5,33,34 Board | substrate 6,7,35,36 Electrode 8,38 Liquid crystal layer 9,43 Photoconductive layer 10 Light absorption layer 11 , 40 Voltage application unit 12, 39 Control unit 13, 44 Light irradiation unit 14, 41 Bias voltage 15, 45 Writing light (incident light)
16, 42 Reading light (external light)
22, 24, 26 Emission spectrum (blue, green, red)

Claims (4)

A liquid crystal layer that reflects external light in a specific wavelength region irradiated from the front surface side, and absorbs incident light in the specific wavelength region irradiated from the back surface side, and changes the resistance value according to the intensity of the absorbed incident light. A plurality of photo-addressable light modulation layers, at least laminated with a photoconductive layer,
Each photoconductive layer constituting the plurality of photoaddressable light modulation layers has a different absorption wavelength range, and each photoconductive layer absorbs incidents in different wavelength ranges irradiated from the back side. The liquid crystal layer corresponding to each of the photoconductive layers whose resistance has changed is an optical address type spatial light modulator that reflects external light in different wavelength ranges irradiated from the surface side,
The incident light in the wavelength region where absorption is overlapped in the absorption wavelength region of the photoconductive layer and the absorption wavelength region of another photoconductive layer is blocked at least on the incident light side of the photoconductive layer irradiated with the incident light. An optical address type spatial light modulation device comprising an optical functional layer.   2. The optical address type spatial light modulator according to claim 1, wherein an absolute value of a difference in absorptance in a wavelength region where absorptions mutually overlap is 50% or less.   2. The optical address type spatial light modulator according to claim 1, wherein only one optical functional layer is provided.   The optical addressing spatial light modulator according to claim 1, wherein the optical functional layer includes a plurality of layers.

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