Recording apparatus for recording information included in an electro-magnetic radiation-beam applied thereto and recording head used for the same

Abstract: A recording apparatus comprises first electrode (14), color-seperation filter (16), recording (12), carrier generation (22a), carrier transport (22b), and second electrode layers (24) which are laminated in order of mention. The recording layer and carrier generation layer may be separated at a given space.The recording layer (12) comprises ca rrier retaining layer or a photo-modulation layer. Light image from an object is projected on the carrier generation layer through the first electrode, color-separation, and recording layers via an object lens enters the carrier generation layer. Carrier generated in the carrier generation layer (22a) in response to the light image are transported to the second electrode in response to application of a given voltage (32) between the first and second electrodes. Discharge caused by application of the given voltage transfers a latent carrier image to the recording layer. The first electrode,color-separation filter and recording layers may be used for recording medium. The carrier generation, the carrier transport, and second electrode layers may be used as a recording head.

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention: This invention relates to an apparatus for recording information carried by a beam of electromagnetic radiation incident thereon, the apparatus comprising a sequence of layers which include: a first electrode layer which is substantially transparent to the incident beam; a second electrode layer facing said first electrode layer, the first and second electrode layers enabling an electric field to be generated between them; a carrier generation layer which is designed so that carriers are generated therein when the beam is incident thereon and at a rate which is related to the intensity per unit area of the beam; a carrier transport layer which is traversed by at least some of the carriers thus generated, said carriers moving under the influence of the electric field generated between the first and second electrode layers; a recording layer which is substantially transparent to the beam and which is provided for recording the information carried by the beam; and wherein the carrier generation layer, the carrier transport layer and the recording layer are disposed between the first and second electrode layers. 2. Description of the Prior Art A recording apparatus for recording information included in an electro-magnetic radiation-bream applied thereto are known, which comprises a recording medium including a color-separation filter and a recording layer. A recording head used for the recording apparatus comprises a photoconductive layer having a carrier transport layer and a carrier generation layer, an electrode layer, and a base layer which are laminated in order of mention. Such prior art recording apparatus and the recording head are disclosed in Japanese patent application JP-A-2-306790 Hereinbelow will be described this prior art recording apparatus and recording head with reference to drawings. Fig. 8 is a perspective view showing the prior art recording apparatus and recording head wherein a photoconductive layer 22 and a recording layer 12 separated are shown. In Fig. 8, a recording medium 10 capable of formation of a latent charge image, comprises the recording, layer 12, a transparent electrode layer 14, a color separation filter layer 16, and a glass base layer 18, which are laminated in order of mention. The recording head 20 comprises the photoconductive layer 22 including a carrier transport layer 22b and a carrier generation layer 22a, an electrode layer 24, and a base layer 26 which are laminated in order of mention. The recording medium 10 and the recording head 20 are arranged such that the recording layer 12 and the carrier transport layer 22b of the photoconductive layer 22 face each other with a given space. An optical image of an object 28 enters there through the glass base layer 18 of the recording medium 10 via the object lens 30. In Fig. 8, a power supply 32 with a given voltage is connected between the transparent electrode layer 14 and the electrode layer 24. It generates discharge between the recording layer 12 and photoconductive layer 22. The color separation filter layer 16 comprises thin bar-shaped filters 16R, 16G, and 16B arranged in order of mention for color-separation by transmitting primary color lights of red (R), green (G), and blue (B) by filters 16R, 16G, and 16B respectively. A charge retaining material for retaining charges on its surface or therein and photo-modulation member whose optical characteristic varies, can be used for the recording layer 12. Hereinbelow will be described operation of recording of the prior art. In Fig. 8, the optical image of the object 28 enters the object lens 30 from the right of the drawing as shown by an arrow F and enters the photoconductive layer 22 of the recording head 20 through the object lens 30 and the recording medium 10. The filters 16R, 16G, and 16B of the color separation filter layer 16 separate the incident light into three primary colors. That is, the filter 16R allows only R component of the incident light to transmit therethrough; the filter 16G, only G component, and the filter 16B, only B component. That is, the filter layer 16 performs color separation. These color-separated transmitted light beams enter the photoconductive layer 22 through the transparent electrode layer 14 and the recording layer 12. The photoconductive layer 22 is formed by laminating the carrier transport layer 22b and the carrier generation layer 22a as mentioned above. The carrier transport layer 22b faces the recording layer 12. Thus, the color-separated light beams are transmitted through the carrier transport layer 22b and enter the carrier generation layer 22a. The incident light beams are absorbed by the carrier generation layer 22a, so that carriers are generated in the carrier generation layer 22a. As mentioned above, the potential of the power supply 32 is applied between the transparent electrode layer 14 and the electrode layer 24. Therefore, holes of the carriers generated in the carrier generation layer 22a move through the carrier transport layer 22b to a surface of the carrier transport layer 22b opposite to the recording layer 12. This movement produces a charge image corresponding to the optical image of the object 28 on the surface of the photoconductive layer 22. Such operation is made for each of separated light beams of R, G, and B, so that positive charge images are formed with respect to every separated light beam. Then, application of the given voltage of the power supply 32 generates discharge between confronting surfaces of the recording layer 12 and the photoconductive layer 22. This discharge produces a charge Q on the surface of the recording layer 12 and is accumulated and retained on its surface. In this case, the degree of the charge due to the discharge corresponds to the positive charge image accumulated. Therefore, an image corresponding to the optical image of the object 28 is transferred on the surface of the recording layer 12. In other words, an amount of a charge per unit area on the recording layer relates to an intensity of light per the unit area. When the charge retaining layer is used for the recording layer 12, a charge latent image corresponding to the optical image of the object 28 is recorded on the surface of the charge retaining layer of the recording medium 10. The positive charges on the charge retaining layer are produced for each of separated light beams, so that for each of the separated light beams of R, G, and B, a charge latent image is formed. When photo-modulation material is used for the recording layer 12, the photo-modulation layer reacts to an electric field, so that an image is recorded as a change in optical characteristic of the photo-modulation layer. However, there is a problem that the resolution decreases and thus, a normal color separation is difficult because an electro-magnetic radiation beam from the object 28 is color-separated and then enters the carrier generation layer 22a through the carrier transport layer 22b whose thickness ranging from several micrometers to tens micrometers. Moreover, there is a possibility that the sensitivity of the carrier generation layer at a specific band would decrease because there is a spectral transmission factor characteristic of the carrier transport layer 22b. SUMMARY OF THE INVENTION The present invention has been developed in order to remove the above-described drawbacks inherent to the conventional recording apparatus for recording information included in an electro-magnetic radiation-beam applied thereto and the conventional record head used for the same. According to the present invention there is provided an apparatus of the initially named kind, characterised in that the carrier generation layer is situated between the carrier transport layer and the recording layer, and in that the recording layer records the information carried by the beam by retaining charge associated with some of the carriers generated by the beam, or in that the recording layer comprises photo-modulation material, and thus records the information carried by the beam by the change in the electro-optic characteristic of the photo-modulation material in response to the electric field modulated by the carriers traversing the carrier transport layer. Thus, in a first particularly preferred variant of the invention, the recording layer records the information carried by the beam by retaining charge associated with some of the carriers generated by the beam. In a second particularly preferred variant of the invention, the recording layer comprises photo-modulation material and thus records the information carried by the beam by the change in the electro-optic characteristic of the photo-modulation material in response to the electric field modulated by the carriers traversing the carrier transport layer. In this second variant of the invention it can especially advantageous when the recording layer and the carrier transport layer are spaced apart at a given distance so that the change in the electro-optic characteristic of the recording layer is produced by a discharge induced by the electric field generated between the first and second electrodes. Furthermore it is preferred if the photo-modulation material is a liquid crystal material, in particular a polymer dispersed liquid crystal material. The liquid crystal material can, for instance, be lead lanthanum zirconate titanate (PLZT). The apparatus in accordance with the invention can, for colour applications, advantageously further comprise a colour-separation filter means including a set of plural different colour filters arranged in at least one direction for colour separation of the beam, wherein the colour-separation filter means is arranged such that the beam incident thereon passes into the recording layer after colour separation by the colour-separation filter means. Another aspect of the invention relates to a recording head for use in a recording apparatus in accordance with the invention and comprises a second electrode layer, a carrier transport layer and a carrier generation layer. It is noted that the layers comprising the recording head have the properties and arrangements ascribed to them further above and described there in relation to the apparatus in accordance with the invention. BRIEF DESCRIPTION OF THE DRAWINGS The object and features of the present invention will become more readily apparent from the following detailed description taken in conjunction with the accompanying drawings in which: Fig. 1 is a perspective view of a first embodiment of the invention of the recording apparatus and recording head; Fig. 2 is a perspective view of a second embodiment of the invention; Fig. 3 is a perspective view of the third embodiment; Fig. 4 is a perspective view of the fourth embodiment of reproduction; Fig. 5 is a perspective view of a fifth embodiment of reproducing; Fig. 6 is an illustration for showing the sixth embodiment of reproducing; Fig. 7 is an illustration for illustrating a seventh embodiment; and Fig. 8 is a perspective view showing the prior art recording apparatus and recording head. The same or corresponding elements or parts are designated as like references throughout the drawings. DETAILED DESCRIPTION OF THE INVENTION Hereinbelow will be described a first embodiment of this invention with reference to Fig. 1. Fig. 1 is a perspective view of a first embodiment of the invention of a recording apparatus and a recording head whose photoconductive layer 22 is separated from a recording layer 12. In Fig. 1, a recording medium 10 capable of formation of a latent charge image, comprises the recording layer 12, a transparent electrode layer 14, a color separation filter layer 16, and a glass base layer 18 which are laminated in order of mention. The recording medium 10 has the same structure as that of the prior art shown in Fig. 8. On the other hand, a recording head 40 comprises the photoconductive layer 22 including a carrier generation layer 22a and a carrier transport layer 22b, an electrode layer 24, and a base layer 26, which are laminated in order of mention. The arrangement of the carrier generation layer 22a and carrier transport layer 22b is different from that of the prior art of Fig. 8. The recording medium 10 and the recording head 40 are arranged such that the recording layer 12 and the photoconductive layer 22 face each other with a given space. An optical image of an object 28 enters the recording medium through the glass base layer 18 via the object lens 30. Fig. 2 is a perspective view of a second embodiment of the invention wherein the photoconductive layer 22 is laminated on the recording layer 12. The second embodiment of Fig. 2 has the same component as that shown in Fig. 1. That is, the second embodiment comprises the glass base layer 18, the color separation filter layer 16, the transparent electrode layer 14, the recording layer 12, the photoconductive layer 11 including the carrier generation layer 22a and the carrier transport layer 22b, and the electrode layer 24 are laminated in order of mention. The recording medium 10 and the recording head 40 are combined together by lamination. In Figs. 1 and 2, a power supply 32 is connected between the transparent electrode layer 14 and the electrode layer 24. It generates discharge between the recording layer 12 and the photoconductive layer 22. The color separation filter layer 16 comprises thin bar-shaped filters 16R, 16G, and 16B arranged in order of mention for transmitting primary color lights of red R, green G, and blue B respectively. A charge retaining material, for example, a high resistance material such as a silicone resin and a material in which photoconductive fine particles are included in and near a surface of the resin, for retaining carriers on its surface or therein can be used as the recording layer 12. The light modulation material, for example, a polymer dispersed liquid crystal film or PLZT (Lead Lanthanum Zirconate Titanate) which records information by change in optical characteristic in response to application of an electric field, can also be used as the recording layer 12. Hereinbelow will be described operation of recording shown in Figs. 1 and 2. The light from the object 28 enters the object lens 30 from the right of the drawing as shown by an arrow F and enters the photoconductive layer 22 of the recording head 40 through the object lens 30 and the recording medium 10. The filters 16R, 16G, and 16B of the color separation filter layer 16 separates the incident light into three primary colors. That is, the filter 16R allows only R component of the incident light to transmit therethrough; the filter 16G, only G component, and the filter 16B, only B component. These color-separated transmitted light beams enter the photoconductive layer 22 through a transparent electrode layer 14 and the recording layer 12. The photoconductive layer 22 is formed by laminating the carrier generation layer 22a and the carrier transport layer 22b as mentioned above. The carrier generation layer 22a faces the recording layer 12. Thus, the color separated transmitted light beams enter the carrier generation layer 22a. The incident light beams are absorbed by the carrier generation layer 22a, so that carriers are generated in the carrier generation layer 22a. As mentioned above, a voltage of the power supply 32 is applied between the transparent electrode layer 14 and the electrode layer 24. Therefore, electrons of the carriers generated in the carrier generation layer 22a move through the carrier transport layer 22b toward the electrode layer 24 by an attraction force from plus polarity of the power supply 32. On the other hand, holes of carriers move to a surface of the carrier transport layer 22b opposite to the recording layer 12. This movement, i.e., an electric field, produces a charge image corresponding to the optical image of the object 28 on the surface of the photoconductive layer 22. Such operation is performed for each of separated light beams of R, G, and B, so that positive charge images are formed for every separated light beam. Then, in the first embodiment shown in Fig. 1 the recording layer 12 and the photoconductive layer 22 are separated from each other, application of potential of the power supply 32 generates discharge between confronting surfaces of the recording layer 12 and the photoconductive layer 12. This discharge produces a charge on the surface of the recording layer 12 and the charge Q is accumulated and retained on the surface. In this case, the degree of the charge due to the discharge corresponds the positive charge image. Therefore, an image corresponding to the optical image of the object 28 is transferred on the surface of the recording layer 12. When a charge retaining layer is used for the recording layer 12, a charge latent image of the optical image of the object 28 is recorded on the surface of the charge retaining layer. The positive charge on the charge retaining layer of the photoconductive layer 22 are produced for each of separated light beams, so that the charge latent images in the recording medium 10 are also formed for each of the separated light beams of R, G, and B. When a photo-modulation material is used for the recording layer 12, the photo-modulation layer reacts by the recording head 40, so that an image is recorded as a change in optical characteristic. Moreover, in the second embodiment where the recording medium 10 and the recording head 40 are combined together, the image can be recorded on the recording layer 12 directly without aerial discharge. In this case, the charge retaining material or the photo-modulation layer can be used for the recording layer 12. Hereinbelow will be described the reproducing operation with reference to Fig. 3. Fig. 3 is a perspective view of the third embodiment for illustrating the operation of reproducing by the recording layer 12 comprising the charge retaining material where a latent charge image is formed. In Fig. 3, the same elements as those shown in Figs. 1 and 2 are designated the same reference. A reproduce head 50 is arranged such that it faces the recording layer 12 comprising a charge retaining material where a latent charge image is formed. The reproduce head 50 comprises a photo-modulation layer 52 made of a photo-modulation material, an electrode layer 24, a base layer 26. The exposed surface of the light modulation layer 52 faces the recording layer 12 of the recording medium 10. A read-out beam L shown by an arrow enters the reproduce head 50 through the recording medium 10. As the read-out light L, white light is used. The light modulation layer 52 produces phase difference between an ordinary ray and an extraordinary ray through electro-optical effect when the read-out light L enters there. A high polymer·liquid crystal composite film or PLZT and the like can be used for the photo-modulation layer whose optical characteristic is changed by application of an electric field. The charge image of the object 28 is formed on the recording medium 10 as mentioned as to Fig. 1. The reproduce head 50 is arranged near the recording medium 10. The transparent electrode layer 14 and 24 are connected the power supply 32, as shown. Then, the electric field of the latent charge Q on the surface of the recording layer 12 effects the photo-modulation layer 52, so that electro-optical effect occurs in response to the incident light. In this state, when the read-out light inters the recording medium 10 as shown by the arrow L, the read-out light L is color-separated in to R, G, and B by the color separation filter 16 as the recording system mentioned above does. Therefore, the color-separated light R, G, and B enters the reproduce head 50 through the color-separation filter 16. When the color-separated light R, G, and B enters the reproduce head 50, electro-optical effect occurs in the light modulation layer 52, so that it enables the reproduction of color image of the object 28. Fig. 4 is a perspective view of the fourth embodiment of reproduction. In Fig. 4, the recording layer 12 is made of a photo-modulation material. There is a difference from the third embodiment in needlessness of the reproducing head 50. The read-out light L transmits the color separation filter 16, enters the photo-modulation layer 12 made of the photo-modulation material, so that electro-optical effect developed provides a color image of the object directly. Fig. 5 is a perspective view of a fifth embodiment of reproducing. In the fifth embodiment, the dichroic mirrors 60 and 62 are provided in addition to the structure of the fourth embodiment. The read-out light L transmitted through the recording layer 12 comprising the color separation filter 16 and the photo-modulation layer enters the first dichroic mirror 60. The first dichroic mirror 60 only transmits a separation light beam G and reflects the remaining components R and B to the following dichroic mirror 62. The dichroic mirror 62 reflects separation light beam R and transmits a separation light beam B therethrough. As mentioned, the dichroic mirrors 60 and 62 separate the read-out light L into components R, G, and B. These components R, B, and B provide reproduction of color-separation image of the optical image of the object 28. If required, it can be converted into an electric signal by a photoelectric conversion means. Moreover, the read-out light L can be projected on a surface two-dimensionally or by using scanning. Fig. 6 is an illustration for showing the sixth embodiment of reproducing for displaying a color image by directly projecting the read-out light L transmitted through the recording medium 10. This embodiment comprises the color separation filter 16 and the photo-modulation layer. The read-out light L transmitted through the recording layer 12 on which a latent charge image is formed is directly projected to a screen by a project lens 64. Fig. 7 is an illustration for illustrating a seventh embodiment. The read-out light L transmitted through the recording layer 12 on which a latent charge image is formed, comprising a photo-modulation layer observed by human eyes through the color separation filter 16. In addition to the strip type of the color separation filter 16 used in Figs. 1 to 7, other types of color filter having a given shape can be used such as an island type. Moreover, other types of color filters having a given combination of passbands other than R, G, and B can be used.

Claims: An apparatus for recording information carried by a beam of electromagnetic radiation incident thereon, the apparatus comprising a sequence of layers which include: a first electrode layer (14) which is substantially transparent to the incident beam; a second electrode layer (24) facing said first electrode layer (14), the first and second electrode layers (14, 24) enabling an electric field to be generated between them; a carrier generation layer (22a) which is designed so that carriers are generated therein when the beam is incident thereon and at a rate which is related to the intensity per unit area of the beam; a carrier transport layer (22b) which is traversed by at least some of the carriers thus generated, said carriers moving under the influence of the electric field generated between the first and second electrode layers (14, 24); a recording layer (12) which is substantially transparent to the beam and which is provided for recording the information carried by the beam; and wherein the carrier generation layer (22a), the carrier transport layer (22b) and the recording layer (12) are disposed between the first and second electrode layers (14, 24); characterized in that, the carrier generation layer (22a) is situated between the carrier transport layer (22b) and the recording layer (12), and in that the recording layer (12) records the information carried by the beam by retaining charge associated with some of the carriers generated by the beam, or in that the recording layer (12) comprises photo-modulation material, and thus records the information carried by the beam by the change in the electro-optic characteristic of the photo-modulation material in response to the electric field modulated by the carriers traversing the carrier transport layer (22b). An apparatus in accordance with claim 1, characterised in that the recording layer (12) and the carrier transport layer (22b) are spaced apart at a given distance and in that the change in the electro-optic characteristic of the recording layer (12) is produced by a discharge induced by the electric field generated between the first and second electrodes (14, 24). An apparatus in accordance with claim 1 or claim 2, characterised in that the photo-modulation material is a liquid crystal material, in particular a polymer dispersed liquid crystal material, and especially preferably lead lanthanum zirconate titanate (PLZT). An apparatus in accordance with one of the preceding claims, characterised in that the recording layer (12) and the carrier generation layer (22a) are spaced apart by a given distance and in that carriers are generated by a discharge induced by the electric field generated between the first and second electrodes (14, 24). An apparatus in accordance with one of the preceding claims, characterised in that the recording layer (12) is laminated on the carrier generation layer (22a). An apparatus in accordance with one of the preceding claims, characterised in that it further comprises a colour-separation filter means (16) including a set of plural different colour filters (16R, 16G, 16B) arranged in at least one direction for colour separation of the beam, and in that the colour-separation filter means (16) is arranged such that the beam incident thereon passes into the recording layer (12) after colour separation by the colour-separation filter means (16). A recording head comprising a second electrode layer (24), a carrier transport layer (22b) and a carrier generation layer (22a), for use in an apparatus in accordance with any of the preceding claims.

Inventors: ASAKURA TSUTOU SHANTEMERU, FURUYA MASATO NANRYO MUTSUURA, KOYAMA YOSHIHISA, NAKAGAKI SHINTARO, TAKANASHI ITSUO, UCHIYAMA YUJI, ASAKURA, TSUTOU, SHANTEMERU 21, FURUYA, MASATO, NANRYO MUTSUURA BLDG., KOYAMA, YOSHIHISA, NAKAGAKI, SHINTARO, TAKANASHI, ITSUO, UCHIYAMA, YUJI
Applicants: VICTOR COMPANY OF JAPAN, VICTOR COMPANY OF JAPAN, LIMITED
Application year: 1991
Main classification: G03G15
IPC codes: G03G5, G03G15, G02F1