JPH0457030A - Optical image information converter - Google Patents

Abstract

PURPOSE:To satisfactorily execute the image information conversion even if image information is in optical intensity of the lowest sensitivity or below, and to execute the optical image display of high fidelity by executing bias light irradiation corresponding to the lowest sensitivity at the time of executing image write of the lowest sensitivity. CONSTITUTION:A write light F2 is made incident on a photoconductive part 62, in which photoconductivity is varied in accordance with an incident light intensity distribution, an electric field of a power source 68 corresponding thereto works on an optical modulating part 66, and a modulation distribution of light is varied. In such a state, when a read-out light is made incident from the F3 direction, it is modulated in accordance with the modulation distribution of light, and this modulated light is reflected by a dielectric mirror part 64 and outputted in the direction as indicated with an arrow F4. In such a way, a light - light converting element 16 executes write of an image once, and executes a light - light conversion by reading out and outputting it optically. Accordingly, even in the case of an image of a feeble light, a display of high luminance and a large screen can be executed by executing read-out by an intense light.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to an optical image information conversion device using a light-to-light conversion element, and particularly relates to an optical image information conversion device suitable when the conversion means has the lowest sensitivity for image information conversion. It is. [Conventional technology]

As an optical image information conversion device using a light-light conversion element,
For example, there are those shown in FIGS. 5(A) and 5(B), respectively. First, in the one shown in FIG. 2A, line-shaped image light output from a light emitting element array 10 enters a vertical deflector 14 via an optical system 12. This linear light then scans the incident surface of the light-to-light conversion element 16 in the direction of arrow F1 as the vertical deflector 14 rotates, thereby writing an image on the light-to-light conversion element 16. . The polarization beam splitter 20 irradiates the light-to-light conversion element 16 with the readout light output from the polarization beam splitter 20 . The read light incident on the light-to-light conversion element 16 is optically modulated in accordance with the written information. The readout light after modulation is transmitted through a polarizing beam splitter 20 and further passes through a projection optical system 2.
2 and onto the screen 24. Next, in the case shown in FIG. 2B, an image of a desired subject 26 is projected and written onto the light-to-light conversion element 16 by the optical system 28. To read the information, the readout light output from the light source 30 is passed through the optical system 32 to the light-to-light conversion element 16.
This is done by irradiating the The read light is output from the light-to-light conversion element 16 after being modulated according to the written information. This readout light is irradiated onto the screen 24 by the optical system 34, whereby an image of the subject 26 is projected. In the conventional example shown in FIG. 3(A), linear light scanning is performed;
In the conventional example shown in Figure (B), such scanning is performed in rows.

[Problem to be solved by the invention]

By the way, the above-mentioned light-light conversion element 16 includes, for example, a photoconductive part and a dielectric mirror part between transparent electrodes. The light modulation sections are each laminated, and the relationship between the writing light intensity on the photoconductive section and the reading light intensity ratio on the light modulation section is, for example, as shown in FIG. 6. As shown in the figure, the writing light intensity is approximately 10-610-6
Below W-, the readout light intensity ratio hardly changes. Thus, the light-light conversion element 16 has the lowest sensitivity. Therefore, optical information below the minimum sensitivity cannot be written, and naturally cannot be read. For this reason, for example, in the conventional example shown in FIG. 5(A), there is an inconvenience in that a correction corresponding to the lowest sensitivity of the light-to-light conversion element 16 must be added to the drive circuit (not shown) of the light emitting element array 10. be. In addition, in the conventional example shown in FIG.
Since the image information is from the subject 26, no correction can be made at all.The present invention was made in view of this point, and the present invention is made in view of the above, and the image information to be subjected to light-to-light conversion has a light intensity below the minimum sensitivity. It is an object of the present invention to provide an optical image information conversion device with good fidelity that can perform image information conversion satisfactorily even when the image information is converted.

[Means for Solving the Problems 1] The present invention provides an optical image information conversion device that converts image information using a light-to-light conversion element in which a photoconductive portion and a light modulation portion are laminated. The present invention is characterized by comprising a bias light irradiation means for uniformly irradiating the photoconductive section with light corresponding to the lowest sensitivity of the light modulation section as bias light when providing image information. Another invention provides a reflective light-to-light conversion element in which a photoconductive part, a dielectric mirror part, and a light modulation part are laminated, and readout light is reflected by the dielectric mirror part to read out an image. The optical image information conversion device used includes a dielectric mirror portion that uniformly transmits light with respect to the lowest sensitivity of the light modulation portion when giving optical image information to the photoconductive portion. It is something. [Operation] According to the present invention, bias light is irradiated by the bias light irradiation means when writing an image on the light-to-light conversion element. This bias light makes it possible to obtain the lowest sensitivity of the light-to-light conversion element, and image light is superimposed thereon to write an image. According to another invention, read light is used as the bias light and is applied to the photoconductive section by passing through a dielectric mirror section. [Embodiment 1] Hereinafter, an embodiment of the optical image information conversion device according to the present invention will be described with reference to the accompanying drawings. Note that the same reference numerals are used for components that are similar or equivalent to those of the conventional example described above. First Embodiment> First, the configuration of the first embodiment is shown with reference to FIGS. 1 and 2. In the figure, the image to be converted is output from the light emitting element array 10 in a line shape. This image light enters a vertical deflector 14 via an optical system 12. The vertical deflector 14 is rotatably driven by a motor 40, and this driving causes the linear light to scan the incident surface of the light-to-light conversion element 16, thereby converting the light to An image is written to the light conversion element 16. Next, the image is read out from the light-to-light conversion element 16 using readout light outputted from the light source 18. The readout light is transmitted through a polarizing beam splitter 20
The light enters the light-to-light conversion element 16, where it is modulated in accordance with the written information. Thereafter, the light is reflected and output and enters the polarizing beam splitter 20 again. Furthermore, images are now being projected onto a screen 24 via an optical system 22. The light-light conversion element 16 has a configuration as shown in FIG. 2, for example. In the figure, transparent electrodes 58, 60 are formed on glass substrates 54, 56 with antireflection films 50, 52, respectively. And these transparent electrodes 58,
Between 60 and 60, there is a photoconductive section 62. Dielectric mirror section 64. The light modulating parts 66 are formed by stacking each other. Further, a driving power source 68 is connected between the transparent electrodes 58 and 60. The writing light enters the photoconductive portion 62 as shown by arrow F2. In the photoconductive section 62 , the photoconductivity changes depending on the incident light intensity distribution, and a corresponding electric field from the power source 68 acts on the light modulation section 66 . Therefore, the modulation distribution of light in the light modulator 66 changes. In this state, when reading light is incident from the direction of arrow F3, it is modulated in accordance with the modulation distribution of the light at the incident position. The modulated light is reflected by the dielectric mirror section 64 and output in the direction of arrow F4. In this way, according to the light-to-light conversion element 16, once an image is written, light-to-light conversion is performed in which the image is read out optically and output. Therefore, even if the image is of weak light, it is possible to display it on a large screen with high brightness by reading it out with strong light. Incidentally, in this embodiment, another bias light source 42 is provided on the image writing side of the light-to-light conversion element 16. This light source 42 uniformly illuminates the entire incident surface of the light-to-light conversion element 16, and the intensity of the illumination light corresponds to the lowest sensitivity shown in FIG. The wavelength of this light source 42 may be any wavelength to which the photoconductive portion 62 of the light-to-light conversion element 16 described above has sensitivity.
It does not matter whether the light is parallel or non-parallel. Next, the operation of the first embodiment configured as above will be explained. First, an image is written on the light-to-light conversion element 16 under illumination from the light source 42 indicated by arrow F5. As a result, the entire light-to-light conversion element 16 is irradiated with light corresponding to the lowest sensitivity shown in FIG. Under such conditions, the linear image light output from the light emitting element array 10 is output as indicated by the arrow F6, and the vertical deflector 14
As shown by the arrow F7, the light-light conversion element 1
An image will be formed on 6. Light-light conversion element 1
6, the photoconductive portion 6 corresponds to the light intensity distribution of the image.
The conductivity of the light modulator 66 changes, and the light modulation distribution of the light modulator 66 also changes. At this time, even if the light intensity of the written image is below the minimum sensitivity, the light transmission band changes favorably due to the light irradiation from the light source 42. Next, the image information written in the light-to-light conversion element 16 as described above is read out in the same manner as in the prior art described above. That is, the readout light output from the light source 18 as indicated by the arrow F8 is incident on the light-to-light conversion element 16 by the polarization beam splinter 20. Then, the light modulator 66 receives modulation corresponding to the written image, is reflected by the dielectric mirror 64, and is transmitted to the polarizing beam splitter 20.
Can I! 7 oki, self-fire cam-,-me, put the fire hner in the middle of the day? (10) While passing through the waste light beam splitter 20,
Screen 2 as shown by arrow F9 by optical system 22
4. As a result, the read image is projected onto the screen 24. As described above, according to this embodiment, the light-light conversion element 16
Since the light source 42 emits light corresponding to the lowest sensitivity possessed by the camera, it is possible to perform good conversion even for image light having an intensity lower than the lowest sensitivity, and faithful image reproduction can be performed. There is an effect. Second Embodiment Next, a second embodiment of the present invention will be described with reference to FIG. This second embodiment is an application of the present invention to the conventional example shown in FIG. 5(B). In the figure, a light source 70 is provided on the image writing side of the light-to-light conversion element 16. This light source 70 corresponds to the light source 42 of the first embodiment described above. The image light of the subject 26 enters the light-light modulation element 16 as indicated by the arrow FIO, but at this time, light from the light source 711>O is irradiated as indicated by the arrow FIL. As a result, a light intensity equivalent to the lowest sensitivity is ensured, and the image of the subject 26 is favorably written to the light-to-light conversion element 16. Image reading is performed by irradiating light from the light source 30 onto the light-to-light conversion element 16 as indicated by arrow F12.degree.13. The readout light that has been modulated in accordance with the written image by the light-to-light conversion element 16 is directed to the screen 24 as shown by arrows F14 and F15.
The image is projected. <Third Embodiment> Next, a third embodiment of the present invention will be described with reference to FIG. Note that the same reference numerals are used for components similar to or corresponding to those in the above-described embodiment. No.-
In both the second embodiment and the second embodiment, a light source that provides bias light is provided, which is not necessarily preferable in terms of device configuration and cost. Therefore, this embodiment has a configuration that can obtain the same effect without requiring a bias light source. 12> In the figure, the dielectric mirror portion 8 of the light-light conversion element 80
2, a plurality of layers having different refractive indexes are partially formed of a light-absorbing material, and characteristics are set so that a portion of the readout light is transmitted to the photoconductive portion 62 side. For example, 5i02N82A and Si
Alternatively, a plurality of light absorption layers 82B made of Ge are alternately formed with an optical thickness of λ/4 with respect to the wavelength λ of the readout light. Then, on top of that, the S i 02 layer 82G is λ/
It is formed with a thickness of 2. The detailed film-forming conditions are disclosed in Japanese Patent Application No. 14662/1999, and this embodiment is an example of that invention in which the type of light absorbing material and the number of laminated layers are changed. Further, the light modulation section 84 may be a TN cell or a LiNbO3 cell, for example.
It is composed of a single crystal and has the effect of changing the polarization and optical rotation state of the incident readout light. That is, the readout light is transmitted through the light modulation section 84 without changing its intensity. Note 1. Other constituent parts are the same as those of the conventional example described above. Further, the transmittance of the dielectric mirror portion 82 formed in this way is Td%, and the light-to-light conversion element 16 described above is
The lowest sensitivity of S W-c m-2°, the transmittance of the light modulation section 84 is Tm%, and the readout light source 18 that enters the light modulation section 84
．． Letting the output light amount of 30 be IrW-cm2, each part is configured so that the relationship S=■r-Td-Tm·10-4 holds true. Next, the operation of the third embodiment as described above will be explained. First, when writing an image, a predetermined amount of light from the reading light source 18.30 is transmitted from the light modulation section 84 side to the light-to-light conversion element 16. irradiated. As described above, this light enters the photoconductive section 62 without changing its intensity. This provides bias light corresponding to the lowest sensitivity. In this state, an image is written in the same manner as in the embodiment described above. Next, image reading is performed by irradiating readout light in the same manner as in the previous embodiment. At this time, the polarization or optical rotation state of the read light changes in the light modulator 84 in accordance with the written image. Therefore, if the readout light is placed under crossed nicols, an intensity change corresponding to the modulated image can be obtained, and thereby the image is read out. According to this third embodiment, since a special light source for biasing is not required, the device can be made smaller and also advantageous in terms of cost. <Other Examples> Note that the present invention is not limited to the above-described embodiments, and may be modified as necessary, such as in the design of the optical system. Further, in all of the above embodiments, reflective light
Although the present invention is applied to a light conversion element, it can also be applied to a transmissive type. Effects of the Invention As explained above, according to the optical image information conversion device according to the present invention, when writing an image to the light-to-light conversion element having the lowest sensitivity, bias light irradiation corresponding to the lowest sensitivity is applied. As a result, even if the image information to be subjected to light-to-light conversion has a light intensity below the minimum sensitivity, image information can be converted favorably, and optical image display with good fidelity can be performed. There is an effect.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a first embodiment of an optical image information conversion device according to the present invention, FIG. 2 is a block diagram showing a light-to-light conversion element in the embodiment, and FIG. FIG. 4 is a configuration diagram of main parts showing a third embodiment of the present invention, FIG. 5 is an explanatory diagram showing a conventional example, and FIG. 6 is an optical
It is a graph which shows an example of the relationship between the incident light intensity of a light conversion element, and read-out light intensity ratio. 10... Light emitting element array, 12, 22, 28, 32.
34...Optical system, 14...Vertical deflector, 16,80
...Light-light conversion element, 18.30... Readout light source, 20... Polarizing beam splitter, 24... Screen, 26... Subject, 42.70... Bias light source, 66 .84...Light modulation section. Patent applicant: Victor Japan Co., Ltd.

Claims (2)

[Claims] (1) In an optical image information conversion device that converts image information using a light-to-light conversion element in which a photoconductive part and a light modulation part are laminated, when giving optical image information to the photoconductive part, the An optical image information conversion device comprising: bias light irradiation means for uniformly irradiating the photoconductive section with light corresponding to the lowest sensitivity of the light modulation section as bias light. (2) A reflective light-to-light conversion element in which a photoconductive part, a dielectric mirror part, and a light modulation part are laminated, and readout light is reflected by the dielectric mirror part to read out an image. In the optical image information conversion device used, when providing optical image information to the photoconductive section, readout light corresponding to the lowest sensitivity of the light modulation section is uniformly transmitted through the photoconductive section as bias light. An optical image information conversion device comprising a dielectric mirror section.