TW200400378A - Projection device using reflective type liquid crystal device - Google Patents

Abstract

The purpose of the present invention is to solve the problem in that the contrast will not increase to the desired level when a reflective type liquid crystal device with vertical alignment is used in an optical system structure in which the optical path is split in front of the color splitting/synthesizing system. Further, large differences will be formed on the projection screen due to the contrast position. Therefore, the solution of the present invention is to allocate the analyzer A7 having Nicol crossed relationship with the light incident onto the polarization means A4. Also, when the liquid crystal layer of the reflective type liquid crystal device A6 is driven to be ON by the image data to be displayed, the analyzer A7 will transmit light, and absorb light without passing the light before the liquid crystal layer is turned off (OFF). The phase retarder plate A5 has uniaxial anisotropy, and its optical axis is tilted with respect to the film surface. Also, its optic axis is set to be perpendicular to the transmission axis of the polarization means A4 adjacent to the phase retardation plate 5, thereby a bright optical system with cheap cost can be realized without using PBS (Polarization Beam Splitter).

Description

200400378 (1) 发明 Description of the invention [Technical field to which the invention belongs] The present invention relates to a projection device using a reflective liquid crystal element. In particular, it uses a (color) color separation / (color) color synthesis method and a reflective liquid crystal. A projection device such as a reflective liquid crystal element that performs a large image (image) on a screen or the like. [Prior art] In recent years, the research on reflective LCDs equipped with reflective electrodes to improve the aperture ratio of pixels has made considerable progress, and projection-type LCD projectors using this reflective LCD have been developed. enter the market. This reflective liquid crystal panel has a higher aperture ratio than the previous transmissive liquid crystal panel, so that a small-sized / high-efficiency projection device (projector) can be realized. Figure 3 2 shows the use of the previous (known) An example configuration diagram of a reflective liquid crystal element projection device. As shown in the figure, it is a reflective projection device 1 of the projection device, which is roughly composed of a light source 11, a polarization beam splitter (PBS: Polarization Beam Splitter) 12, a dichroic prism 14, a reflective LCD screen 16R, 16G , 16B (R is red, G is green, B is blue), and the projection lens I7 and the like. In the above structure, the light beam emitted (emitted) from the light source 11 is extracted by the polarized beam splitter (polarized light splitter) 1 2 while the polarized polarized light is bent, and the traveling direction is bent at 90 ° to be incident into the two directions. Color 稜鏡 14. The light incident on the dichroic color 414 will be separated into red, green, and blue primary colors of -5- (2) (2) 200400378 (RGB), and the light corresponding to each primary color will be emitted. After each of the reflective liquid crystal panels 16 R '1 6 G and 16 B are reflected, they pass through the same optical path and re-enter the polarized (polarized light) light to separate 稜鏡 1 2. At this time, among the reflection-modulated LCD screens 16 R, 16 G, and 16 B, the reflected light corresponding to the region where the liquid crystal is in the ON state will cause polarized light. The (polarized) light direction is rotated by 90 ° for reflection. Therefore, the transmitted polarized light is separated from the projection lens 12 and projected from the projection lens 17 toward a screen (not shown) to form an image. In the above-mentioned conventional reflection-type projection apparatus 10, since polarized light separation 稜鏡 12 using expensive optical components is used, there is a problem that the cost of the reflection-type projection apparatus 10 is increased. When polarized light (hereinafter referred to as polarized light or polarization) is separated 稜鏡 1 2 when polarized light is separated, it also has a so-called widening of the light of the light source 1 1 (for example, a widening of ± 12 degrees), which is difficult to form The problem of polarized light is well separated. In order to solve this problem, a proposal discloses a projection device using a reflection type liquid crystal element that makes light that does not use polarized polarized light split (PBS) incident at an oblique direction (Japanese Patent Laid-Open No. 2000-1998998) Bulletin). Figure 3 3 shows the structure of a projection device according to the proposal. In the same figure, as the previous reflective projection device 20 of the projection device, the light emitted from the light source 21 will be reflected by the reflector 22 into slightly parallel light, and will directly enter the first polarizing plate 2 3, And after making a linear polarized light (S polarized light or P polarized light) here, it is incident on a color separation / color synthesis means (dichroic 稜鏡 or dichroic mirror). The color separation / color synthesis method (here, dichroic color 24) will separate white light -6- (3) (3) 200400378

It is the three primary colors of RGB, and is incident on the reflective LCD screens 26R, 26G, and 26B. If the right-side reflective LCD screens 26R ', 26G, and 26B use a vertical alignment LCD screen, no voltage is applied to the reflective LCD screen. When the panel and the liquid crystal molecules form a state of vertical alignment (orientation), the person emits light; the polarization state will remain unchanged and this state is maintained to be reflected on the reflective liquid crystal panels 26R, 26G '26B. At this time, after the reflected light passes through the dichroic lens 24, the second polarizing plate in front of the projection lens 27 is placed in front of the projection lens 27 in a cross-Nicol relationship with the first polarizing plate 23. Since it is absorbed by 2 5, it is not projected on the projection lens 27. That is, black display will be realized. On the other hand, when a voltage is applied to the reflective LCD screens 26R, 26G, 2 6B and the liquid crystal molecules are laid down to a horizontal state, the polarization state of the Λ light will change, and the incident light will be on the reflective LCD screen. 26R, 26 G '2 6 B are reflected. At this time, the reflected light passes through the dichroic lens 24 again, passes through the second polarizing plate 25, and is projected by the transmissive lens 27. That is, a white display is achieved. The dichroic element 24 of the color separation / color synthesis means has the function of color separation of the incident light from the light source 21 into three primary colors and each incident on the reflective LCD screens 20R, 26G, and 26B. The power state of the light reflected by the reflective LCD screens 26R, 26G, and 26B. The main axis of the incident light must be incident on the reflective surface of the reflective liquid crystal panel 26R, 26 G, 2 6 B in the state of S wave or P wave. That is, when incident in a state other than that, due to the difference in the reflection characteristics of the dichroic tincture 24, the reflective LCD panel 26R, 26G, 26B is trans--7- (4) (4) 200400378. And the polarization state of the light passing through the dichroic color twice will not be polarized in a straight line, so that a good black display cannot be obtained. In addition, the alignment of liquid crystal molecules needs to be able to form a slightly vertical alignment. In this projection device, when the light incident with the S wave (P wave) is incident on the reflective liquid crystal panels 26R, 26G, and 26B in a vertical orientation, the polarization state does not change. That is, the polarization direction of the incident linearly polarized light is perpendicular or parallel to the optical axis of the vertically aligned liquid crystal branch, so it does not disturb the polarization state, and can maintain the original state to reach the second polarized light The panel 25 is absorbed by it and realizes a black display. As another example of the colorization of the optical system, the projection device as shown in Fig. 34 has been well known in the past. The same figure (A) is a plan view of the reflective projection device 30, and the same figure (B) is a side view of the reflective projection device 30. The reflection type projection device 30 of the previous (known) projection device is composed of: a light source 21 for generating illumination light; a reflector 22 for slightly reflecting the illumination light in parallel; and a predetermined polarization characteristic (for example, Aurora) polarizing plate 3 1; dichroic orthogonal 稜鏡 32 with different reflection characteristics due to polarization; color generation function for generating light incident on dichroic orthogonal 稜鏡 32 Polarizing light control element 33; and a reflective display element 3 4R, 34G, 34B arranged near the dichroic orthogonal 稜鏡 32 (while the light source 21, reflector 22, polarizing plate 31 and polarizing light control element 33, will constitute the lighting system). The reflection type projection device 30 includes a projection lens 36. In this reflective projection device 30, after the light emitted from the light source 21 is linearly polarized by the polarizing plate 31, it will pass through the color separation and synthesis system, and will be output by the birefringence generated here. The formation is uneven, and the contrast obtained by -8- (5) (5) 200400378 is also low. Liquid crystal elements used for reflective projection elements 3 4 R, 3 4 G '3 4 B, although the alignment direction of the liquid crystal molecules is required to be approximately vertical, when the electric field is applied, the tilt direction of the liquid crystal molecules may be confused and generated. The discontinuity of the alignment state has the disadvantage of making noise appear when mapping subtle images. It also has the disadvantages of the so-called dichroic orthogonal 稜鏡 32 and reflective display elements 34R, 34G, and 34B, and the interference stripes are revealed in the projected image. Also in Japanese Patent Laid-Open No. 2001-5 1 270, a proposal has also been disclosed that a projection device that can realize a low cost and have a good contrast ratio (contrast coefficient) without using expensive (high-priced) PBS is used for this purpose. This is the projection device 40 shown in FIG. 35. In FIG. 3, the slightly parallel light L1 emitted from the light source 41 becomes the condensing light L2 by the condensing lens 42, and is incident on the display element 45 from the oblique direction through the plate 43 and the multilayer birefringent element 44. In the display element 45, the incident light will change its polarization direction in response to the image information and reflect it. As for the reflected light, it passes through the multilayer birefringent element and the polarizing plate 43 again, and the transmission lens 46 reaches the screen (not shown) and maps the image. The 40th series of this projection device reveals that the alignment axis aligned closest to the birefringent element and the alignment direction of the liquid crystal are aligned, so it will become a birefringent element that does not require birefringence compensation from the oblique direction. Technology. Although the projection device 40 does not specifically disclose the method of making color images, it can be thought of as a structure that allows light that passes through the color separation system to be incident on the color synthesis system by means of polarization and analysis (analysis). . At this point, it is indeed different from the previous reflective projection device 30-9-(6) (6) 200400378 'and it is formed as an optical system that does not have the influence of birefringence in the color separation and synthesis system. However, the previous projection device 40 has the following problems. Since the means for polarizing or detecting the light is the same, it is impossible to avoid the influence from the reflective surface of the display element 45, and interference lines will be displayed on the projection screen. The multi-layer birefringent element 44 is strictly required to be generated at a wide band of light wavelength; if the phase difference of I / 4 wavelength occurs, if any of the characteristics constituting the multi-layer birefringent element 44 fails (not according to its characteristics) In this case, a deviation occurs from this condition, and when the light is enhanced by irradiating light from a projector or the like, the characteristics are quickly deteriorated. In particular, in recent years, the miniaturization of components has progressed, so that when the utilization efficiency of the light source .41 is improved, the illumination (brightness) of the illuminated surface is increased. Such a problem becomes significant especially in the previous projection device 40. The conventional device 40 ′ birefringent element (phase difference plate) 44 described in Japanese Patent Application Laid-Open No. 200 1 -5 1 270 shown in FIG. 35 is a λ / 4 wavelength plate. A conventional display has disclosed a projection display device using a birefringent optical material having an inclined optical axis (Japanese Patent Application Laid-Open No. 9-1973973, Japanese Patent Application Laid-Open No.2000-321576). There are also many documents that have disclosed retardation plates in optical systems to improve the visible angle characteristics. For example, the conventional projection device described in Japanese Patent Application Laid-Open No. 9-1 9 73 97 described above uses a retardation plate having an inclined axis. This device is not a reflective liquid crystal screen, but a transmissive liquid crystal screen. The transmissive liquid crystal screen with polarization means and detection means on both sides of the liquid crystal cell is equipped with -10- (7) (7) 200400378 The optical compensation sheet of the retardation plate is between the liquid crystal element and the polarization means, or between the liquid crystal element and the detection means, or between the liquid crystal element and the polarization means, or the detection means. With this conventional device, it is revealed that the contrast when viewed from the oblique direction of left, right, up and down can be improved without reducing the contrast when viewed from the front. However, the conventional device has a very low contrast ratio of about 100, and the situation of a contrast ratio of more than 50: 1 required by the projector has not been discussed. Since the liquid crystal panel is of a transmissive type, it can transmit only one time to the liquid crystal element, without taking into account the characteristic deviation or the influence of reflection from the substrate when transmitting the liquid crystal layer twice. Also, Japanese Patent Application Laid-Open No. 2000-3 2 1 5 76 discloses a display device using a nematic liquid crystal reflection type active matrix element and superimposed into an inclined retardation plate. Since a reflective liquid crystal element is used, it is possible to display high brightness and brightness, and it is also possible to display a high-definition image. Therefore, it is superior to the conventional device described in Japanese Patent Application Laid-Open No. 9-1 973 9 7 described above. However, the light that enters the element passes through the same retardation plate, so the contrast that can be obtained is less than 10, and it is not at all the level that the projector element can use. There are proposals to disclose before the color separation and synthesis system Optical System Document 1 (Journal of the SID 9/3, 2001 p213; Matthew Bone, Front-projection optical design for reflective LCOS technology). According to this optical system, the light emitted from the light bulb is separated into RGB by the color separation optical system, and then polarized by a polarizer (polarizer) to enter the reflective liquid crystal element, and the reflected light is reflected in color Synthetic-11-(8) (8) 200400378 was analyzed before analysis, so it is called to obtain a contrast of 3 00 ~ 5 00: 1. However, in the optical system described in the above-mentioned Document 1, when a vertical alignment reflective liquid crystal element is used, it does not increase the expected degree of contrast, and it also has the problem of a difference caused by the position of the contrast on the projection screen. Various proposals have also been made to disclose a dielectric liquid crystal mode in which a dielectric anisotropy of a type in which a liquid crystal is formed substantially on a substrate when no voltage is applied is a positive nematic liquid crystal. For example, Japanese Unexamined Patent Publication No. 1 0-9073 1 discloses self-compensated twisting (SCTN: Self-Compensated Twisted).

Nematic) mode, and it is disclosed in JP 2000-2843 3 1 and JP 2000 · 298277, or in Document 2 [Japan Display '89, pl92 (1989)]. TN-ECB (Twisted Nematic-Electrically Controlled Birefringence) mode, commonly known as MTN (Mixed Twisted Nematic) mode, and in Reference 3 [Appl.  PhysLeft.  68, p. 1 45 5 (1 996)] also revealed the MTN mode. These modes will be used when the voltage is not applied, or a threshold voltage is applied, and it will display white, and when the voltage is fully applied, it will display black. Normally (normally) a white reflection type twist direction. Column liquid crystal display mode (NW mode). However, in these modes, when a sufficient voltage is applied, the liquid crystal can be made vertical and black, but even if the voltage is applied, the liquid crystal molecules will become close to horizontal alignment, which will cause a delay. There is a problem that the so-called black level becomes poor. When the voltage is fully applied, the active matrix driving voltage needs to be increased. For this reason, the transistor will become -12- (9) (9) 200400378, which will damage the so-called reflection that can make pixels with high density. The advantages of the liquid crystal element. In addition, there is a problem that the so-called viewing angle becomes bad. As described above, the conventional video devices using the above-mentioned various liquid crystal display elements have a long and a short. There is no proposal to disclose a projection device of a reflection type liquid crystal display element which can obtain a contrast ratio of 5 00: 1 or more without using interference and hardly produces unevenness of left and right. The present invention was invented in view of the above points, and an object thereof is to provide a projection device using a reflective liquid crystal element capable of obtaining a high contrast (500 or more) required as a projection device. Yet another object of the present invention is to provide a projection device that does not use PBS and uses a reflection type liquid crystal element that hardly generates interference fringes or uneven left and right. Furthermore, another object of the present invention is to provide a projection in a reflective liquid crystal element that can obtain sufficient contrast from a low driving voltage and has a good viewing angle in the MTN mode or the SC TN mode. Applicant 〇 In order to achieve the above-mentioned object, the present invention is a projection device that uses a three-primary-color light transmission polarization means obtained by color separation of light emitted from a light source by color separation means, and is incident on a liquid crystal layer sandwiched therebetween. The reflective liquid crystal element formed between the transparent substrate and the reflective substrate, and the reflected light from the reflective liquid crystal element modulated by the image data in accordance with the image data is adjusted by the polarizing means. The polarizer (pole) means configured in a relationship of orthogonal Nicols is used to detect the polarizer, and the projection lens -13- (10) (10) 200400378 magnifies and projects the light of the polarizer light detected by the polarizer means. The reflection type liquid crystal element of the oblique projection optical system is characterized in that it lies between the polarization means and the reflection type liquid crystal element, or between the reflection type liquid crystal element and the analysis Between the polar means, there is a retardation plate having uniaxial anisotropy, and the optical axis of the retardation plate is inserted at an oblique direction to the film surface, and the optical axis of the retardation plate is set to be orthogonal to the adjacent The transmission axis of the polarization means or the analyzer means of the phase difference plate. In the present invention, a phase difference plate having uniaxial anisotropy and whose optical axis is inclined to the film surface is inserted between the polarization means and the reflective liquid crystal element or the reflective liquid crystal element and the polarization (polar) means. Moreover, the optical axis of the phase difference plate is set to be orthogonal to the transmission axis of the polarization means or the detection means adjacent to the phase difference plate, so that it can be reflected by the reflective liquid crystal element, and it can be reduced by the detection means. Black level of absorbed reflected light. In addition, without using a polarized beam splitter (PBS), polarization means and detection means can be used to analyze (analyze) only a predetermined P-polarized light or S-polarized light. The above-mentioned reflective liquid crystal element uses a nematic liquid crystal with a negative dielectric anisotropy to make a pretilt angle of 80 to 89 degrees, and sets the azimuth angle to (45 + 90n) degrees for incident polarized light [but η is Integer angle], and the optical axis of the retardation plate is set parallel to the incident plane of the polarized P polarized light. The above-mentioned polarization means is set to pass the characteristics of the S polarized aurora. Between the polarization means and the reflection type liquid crystal element, the reflection type liquid crystal element makes the nematic liquid crystal with negative dielectric anisotropy to make a pretilt angle of approximately 80 to 89 degrees, and sets the incident polarized light to -14- (11) (11) 200400378 The azimuth angle is (45 + 90n) degrees [but η is an integer angle], and the optical axis of the retardation plate is set to be parallel to perpendicular to the incident S-polarized light vibration Face to face. The phase difference plate described above can also be configured to have a dish-shaped liquid crystal as a basic negative uniaxial anisotropy, and the inclination of the dish-shaped liquid crystal will be approximately the same on the top and bottom of the film, and its pretilt angle is 40 degrees to 8 〇 degrees, and also has a dish-shaped liquid crystal as a basic negative uniaxial anisotropy, when the tilt of the upper and lower dish-shaped liquid crystals of the film changes, it can also be configured so that the dish-shaped liquid crystal tilts the larger one in opposite directions. The present invention is to make the phase difference plate close to the polarization means or the detection means to be integrated with the polarization means or the detection means to eliminate the excessive surface reflection so as to improve the transmittance. In the present invention, the retardation plate is configured to adhere to a back surface of a glass plate having a reflection prevention layer formed on the surface. As a result, unnecessary interface reflections can be reduced. As another aspect of the present invention, when a reflective liquid crystal element of the NW mode is used, S-polarized light is used as the incident light, and a retardation plate having an optical axis inclined to the film surface obliquely is used for the polarization means and the reflective type. Between the liquid crystal elements, or between the reflective liquid crystal element and the analyzer, and the optical axis of the phase difference plate is set parallel to the transmission axis of the polarization means or the analysis means adjacent to the phase difference plate , The black level of the reflected light absorbed by the analyzer can be reduced. In the state without using a polarized beam splitter (PBS), a sufficient contrast can be obtained by the aforementioned polarization means and the analyzer -15- (12) (12) 200400378. The above-mentioned NW-mode reflective liquid crystal element has a nematic liquid crystal prepared with a pre-tilt angle of 2 degrees to 5 degrees, a twist angle of the liquid crystal layer of 80 degrees to 90 degrees, and an orientation angle of the liquid crystal alignment on the transparent substrate side is In the range of 190 degrees to 200 degrees or 280 degrees to 290 degrees, the normalized retardation of the wavelength of the liquid crystal layer is 0.35 or more. MTN mode below 55. Or the above-mentioned NW mode reflective liquid crystal element is to make the nematic liquid crystal to have a pre-tilt angle of 2 to 5 degrees, the twist angle of the liquid crystal layer is about 60 degrees, and set the liquid crystal alignment on the transparent substrate side and the reflective substrate side. The azimuth angle is any one of about 150 degrees and about 210 degrees, or any one of about 300 degrees and 30 degrees, and the normalized retardation of the wavelength of the liquid crystal layer is 0.55 or more. · SC TN mode below 65 [Embodiment] Hereinafter, a projection device using a reflective liquid crystal element according to an embodiment of the present invention will be described with reference to the attached drawings. FIG. 1 (A) is a block diagram showing a first embodiment of a projection device using a reflective liquid crystal element according to an embodiment of the present invention, and FIG. 1 (B) is a diagram showing a reflective liquid crystal element according to an embodiment of the present invention. Block diagram of a second embodiment of the projection apparatus. As shown in FIG. 1 (A), the light emitted from the light source A1 is subjected to color separation by transmitting the lens group A2 and the color separation optical system 3A that separates colors into three primary colors of RGB, and transmits the polarization means. A4 and the retardation plate A5 are incident on the reflective liquid crystal element A6 formed between the transparent substrate and the active matrix reflective substrate by sandwiching the liquid crystal layer. -16- (13) (13) 200400378 The reflection type liquid crystal element A6 uses the light modulated by the image data to enter the polarization means A4 into an orthogonal Nicocol relation configuration. (Pole) Means A 7 to detect deviation. When the liquid crystal layer of the reflective liquid crystal element A6 is turned on by displaying image data, the analyzer A7 transmits incident light, and when the liquid crystal layer is not driven to be disconnected, the analyzer A7 absorbs incident light and Will not pass. As for the light passing through the analysis means A7, after the color synthesis optical system A8 performs color synthesis, the projection lens A9 is used to project the light onto a screen (not shown). Furthermore, it is necessary to equip the polarization separation means A4 after the color separation optical system A3 and the polarization detection means A7 before the color synthesis optical system A8. From the perspective of designing the optical system, although the main polarization adjustment function can be set before the color separation optical system A3, after the color separation optical system A3, it must be equipped with a straight line that can cause the color separation optical system A3 to deteriorate. The polarized light state becomes a good polarization means A4. In the oblique projection optical system [off-axis], the phase difference plate A 5 arranged between the polarization means A 4 and the reflective liquid crystal element A 6 has uniaxial anisotropy, and its optical axis For the film surface tilted obliquely, the optical axis is set orthogonal to the transmission axis of the polarization means A4 adjacent to the retardation plate A5. Therefore, it is possible to realize a bright optical system at low cost without using PBS. Next, a second embodiment of the present invention will be described using a block diagram of Fig. 1 (B). In FIG. 1 (B), the same components as those in FIG. 1 (A) are denoted by the same reference numerals and their descriptions are omitted. In this second embodiment, it is characterized in that a uniaxial -17- (14) (14) 200400378 anisotropy is inserted into the above-mentioned oblique projection optical system (out-of-axis), and the optical axis thereof faces the film surface. The phase difference plate B 1 where the oblique direction is inclined and the optical axis thereof is orthogonal to the transmission axis of the analyzer 7. As a result, a bright optical system can be realized inexpensively without using PBS. (Examples) Next, examples of the present invention will be described. FIG. 2 (A) and (B) are the first embodiment of the projection device using the reflective liquid crystal element according to one embodiment of the present invention, and the black and white displays of the first and second embodiments are shown. Structure diagram. In FIGS. 2 (A) and (B), a projection device 50 using the reflective liquid crystal element according to the first embodiment of the present invention is arranged on the incident light path to the reflective liquid crystal element, and a straight line is taken out from the incident light. A first polarizing (polarizing) plate 52a for polarized light and a retardation plate 53 having an inclined structure in the axial direction, and a second pole is disposed on the light path of the reflected light from the reflective liquid crystal element 51. Chemical plate (analyzer) 5 2b. The reflective liquid crystal element 51 has a transparent substrate 54 and a reflective substrate 55 which are arranged to face each other, and has a liquid crystal layer 56 interposed therebetween. Furthermore, although not shown, a transparent electrode having a common electrode is formed on the facing surface of the transparent substrate 54, and a plurality of matrices are formed on the facing surface of the reflective substrate 55 to form each pixel. MOS transistors, TFT drive circuits, and reflective electrodes. The pixel size is, for example, a small pixel of about 10 μΐΏ X 10 μιη. The liquid crystal molecules forming the liquid crystal layer 56 are nematic liquid crystals having a negative dielectric anisotropy of a vertical alignment type. On the surfaces of the transparent substrate 54 and the reflective substrate 55 that are in contact with the liquid crystal layer 56, for example, an alignment film (not shown) made of a polyfluorene-18- (15) (15) 200400378 imine film that is subjected to a rubbing treatment is formed. In addition, the liquid crystal molecules in the initial state are given an inclination angle of, for example, about 80 to 89 degrees, and a plane azimuth angle of about 45 degrees is given to the polarization axis of the polarizing plate. Fig. 2 (A) shows a state where no electric field is applied to each pixel electrode (in the initial state, the display will show a black normal black (NB) mode, and the liquid crystal layer is in an open state. The same figure (B) shows The mode of displaying white is the state when the liquid crystal layer 56 is driven to be turned on. Next, the operation of this embodiment will be described. In FIGS. 2 (A) and (B), light emitted from a light source not shown is shown in FIG. First, only the P polarized aurora is taken out by the first polarizing plate 52a, and then modulated by the retardation plate 5 3 whose axis direction is inclined, and incident on the reflective liquid crystal element 51. The axial direction is a phase difference plate which is inclined. The optical axis of 53 will be arranged in the plane where the P polarized aurora vibrates. The phase difference plate 53 having an inclined axis will be disclosed in, for example, Japanese Patent Laid-Open No. 9-1 97397 or Japanese Patent Laid-Open No. 2000-32 1 The disc-shaped (circular) liquid crystal on the substrate of the No. 576, etc. The light incident on the reflective liquid crystal element 51 will be reflected by the liquid crystal layer 56 and the reflective electrode on the reflective substrate, and then pass through the liquid crystal layer 56 and The transparent substrate 54 comes out and enters the second polarizing plate [analysis (pole) Mirror or analyzer [52b] Here, if an electric field is not applied to each pixel electrode and the liquid crystal layer 56 is disconnected, the polarization state of the incident light will remain unchanged and be reflected on the reflective substrate 55 as it is. At this time, the reflected light is absorbed by the second polarizing plate (analyzer) 52b provided in front of the projection lens 57, so it will become as shown in FIG. 2 (A), and will not enter the projection lens. 5 7. That is, black display will be realized. -19- (16) (16) 200400378 On the other hand, when an electric field is applied to each pixel electrode to drive the liquid crystal layer 56 to be turned on, the reflective liquid crystal element The incident light polarization state of 51 is rotated and reflected by the reflection plate 55. At this time, the reflected light is formed as shown in FIG. 2 (B) and passes through the second polarization plate (analyzer) 52b. And the projection lens 57 is used to magnify and project on a shadow screen (not shown). A pre-tilt angle of the liquid crystal layer 56 is 85 degrees will be described as an example. As a retardation plate 5 3 having a tilt axis For the characteristics, for example, the substrate-side angle is 4 degrees, and the surface-side angle is 80 degrees. Only those with an inclined axis will be used. The retardation plate 5 3 is inserted in a crossed Nicols state, and the change in transmittance measured by the optical system in which the first polarizing plate 5 2 a and the second polarizing plate (analyzer) 5 2 b are measured is shown in Figure 3. In the same figure, the vertical axis shows the transmittance, and the horizontal axis shows the polar angle. As shown in the figure, the transmittance characteristics show the maximum near the polar angle of -60 degrees, and the smallest near 35 degrees. Use this phase The actual system of the differential plate 53 is shown in Fig. 4 to simulate the visible angle characteristics obtained. When the azimuth angle is 90 degrees, it can be seen that the black level of the polar angle is around I5 to 20 degrees. [In Fig. 4, the circle with a dashed line is a unit of a pole angle of 20 degrees, and the circle with the smallest diameter shows a pole angle of 20 degrees: (the following visual angle characteristic diagram is also displayed in the same manner)]. Let the angle of the light incident on the liquid crystal layer 56 be about 12 degrees, and F 投影 of the projection lens be 2.4. (The angle of the lens taken in this state is about 12 degrees. When the projection angle is 0 ~ 24 degrees and the azimuth angle is 2 5 8 ~ 2 72 degrees), the contrast is about 6 5 0: 1 and there is no left and right contrast tilt (uneven left and right). And can form a uniform display. Neither the interference phenomenon caused by the surface or the (environment) interface was observed. Next, a second embodiment of the present invention will be described. Although the structure of this embodiment is the same as that of the first embodiment shown in FIG. 2, as the retardation plate 53 having an inclined axis, for example, a substrate side angle of 10 degrees and a surface side angle of 70 degrees are used. There are differences. The visible angle characteristic of this embodiment is as shown in FIG. 5, and it can be seen that there is a visible angle in the azimuth direction of the black level near the enlarged pole angle of 10 degrees in the azimuth angle of 90 degrees. And the contrast when projected on the screen is about 600: 1, and it is uniform without the left and right contrast inclination, and the interference phenomenon caused by reflection on the surface or inside the (boundary) interface is not observed. The first comparative example will be described when the retardation plate 53 having the inclined axial direction is not inserted, and the differences between the first comparative example and the second embodiment will be described. The structure of the first comparative example is the same as that of FIG. 2 except for the phase difference plate 53-free. In this first comparative example, the tilt of the black level in the left and right directions can be seen on the screen actually projected. Although the contrast is high at 700: 1, the contrast is 300: 1. Interference caused by internal reflections at the surface or interface was also observed. The visible angle characteristics of the first comparative example are shown in FIG. 6. The visible angle characteristic of FIG. 6 shows that when a voltage is applied to the black display of the liquid crystal, if the liquid crystal has a pre-tilt angle (degrees), the position where the contrast can be obtained is in the center, although it will be in the polarization direction and positive The contrast of the directions crossing the polarization direction is high, but especially from the angle of incidence of the oblique light with a polarization direction of 45 degrees, the light will leak quickly, so that the black level is increased, and the contrast will be reduced. When viewed from the angle of 90 ° (equivalent to obliquely observing the state of light incident and reflected from oblique -21-(18) (18) 200400378 from below), the polar angle becomes smaller when viewed (When the light is incident obliquely), the black level that can be obtained corresponding to the azimuth angle will be changed. This situation means that on the projected picture, 'has a black level tilt to the left and right, so that it has a contrast tilt to the left and right. This phenomenon will be observed as three reflection LCD screens during color synthesis, and the color unevenness caused by the inconsistencies will be extremely significant. Furthermore, FIG. 7 shows the emphasis of the visible angle characteristics. As shown in the figure, usually (on the axis: ON axis) is perpendicularly incident light and perpendicularly exits, so the characteristics of the central part of the circle are extremely important, but when it is off-axis, the incident light is oblique, making the part The characteristics become important. In general, incident light is ideally parallel light, but it is irradiated with convergent light anyway, so that the light is irradiated in a (reverse) cone shape. The enlarged angle of the cone is called the cone angle, and the range characteristic of the light at this angle becomes important. For example, when the light with a cone angle of 15 degrees lies outside the above axis, the center of the light is at a polar angle of 0 degrees (just at the center). Therefore, if the cone angle is included, the polar angle will be 15 degrees (radius 15). The circle will become an important part. If, for example, a state where light is incident from a azimuth angle of 270 ° and a polar angle of 16 degrees (16 degrees from vertical tilt) is considered, the reflected light will become a graph centered at an azimuth angle of 90 degrees and a polar angle of 16 degrees. The range within the ellipse shown in 7. When viewed from this point of view, it can be seen that in this embodiment, the blackness of the portion becomes good. As described above, according to the second embodiment described above, it is bright without the use of PBS, and an inexpensive optical system can be realized. Although it is necessary to incident light into the device in an oblique direction, it can be adjusted only around the angle of incidence. The most appropriate condition is -22- (19) (19) 200400378, which makes it possible to obtain extremely high contrast. Furthermore, according to the above-mentioned second embodiment, the conditions of the polarizing plate are not strict, and the polarization means (the first polarizing plate 5 2a) and the detection due to reflection from the surface or interface of the reflective liquid crystal element ( Pole) (second polarizing plate 52b), because it has an independent orthogonal Nicol relationship, it does not cause the projection of interference fringe on the screen. After the color separation, it has the polarization means and the detection means, and the color synthesis is performed after the polarization detection. Therefore, it does not have the problem of reducing the polarization purity by the birefringence in the color separation and color synthesis system. It has the characteristics of being stable to heat and the like. However, in the first and second embodiments described above, the retardation plate 53 having a uniaxial anisotropy inclined toward the oblique direction is made parallel to the incident P-polarized polarized light vibration plane, so that the retardation of the retardation plate 53 is delayed. The range (product of refractive index difference and film thickness) becomes narrow, and the visible angle characteristics that can be obtained become narrow. For this reason, in the third embodiment described below, the incident polarized light is regarded as the S polarized light, and a retardation plate having a uniaxial anisotropy inclined obliquely is formed to form a vibrating surface with the incident S polarized light. The orthogonal planes are parallel. Hereinafter, a third embodiment of the present invention will be described with reference to FIG. 8. 8 (A) and 8 (B) are structural diagrams showing a third embodiment of a projection device using a reflective liquid crystal element according to an embodiment of the present invention during black display and white display. As shown in FIGS. 8 (A) and 8 (B), a projection device 60 using a reflective liquid crystal element according to a third embodiment of the present invention is provided with incident light on the optical path of the incident light to the reflective liquid crystal element 61. Take out the first polarizing plate 62a of the linearly polarized aurora and the retardation plate 63 having a structure in which the axial direction is inclined, and arrange a second polarizing plate (inspection) on the optical path of the reflected light from the reflective liquid crystal element 61. Polarizer) 6 2 b. -23- (20) (20) 200400378 The reflective liquid crystal element 61 has a structure in which a transparent substrate 64 and a reflective substrate 65 are arranged to face each other, and a liquid crystal layer 66 is interposed therebetween. In addition, although not shown, a transparent electrode having a common electrode is formed on the opposite surface of the transparent substrate 64, and a MOSFET formed on each pixel is formed on the opposite surface of the reflective plate 65. A crystal, a driving circuit such as a TFT, and a plurality of reflective electrodes are formed in a matrix. As the pixel size, micro pixels with a shape of, for example, 10 μm × 10 μm are formed. As the liquid crystal molecules constituting the liquid crystal layer 66, a nematic liquid crystal having a negative dielectric anisotropy of a vertical alignment type is used. On the surfaces of the transparent substrate 64 and the reflective substrate 65 that are in contact with the liquid crystal layer 66, an alignment film (not shown) made of silicon oxide, for example, which is aligned by vapor deposition, is formed to provide alignment to the liquid crystal molecules, and For example, a tilt angle of about 80 to 89 degrees and two azimuth angles of about 45 degrees to the polarizing axis of the polarizing plate are provided. FIG. 8 (A) shows a normal black (NB) mode that shows black when no electric field is applied to each pixel electrode. Figure 8 (B) shows a white mode. Next, the operation of the third embodiment will be described. As shown in FIGS. 8 (A) and (B), light emitted from a light source not shown is first separated into three primary colors of RGB by a color separation optical system (not shown), and then the first polarizing plate 62a only The S-polarized light is taken out, and then modulated by a retardation plate 63 which is inclined in the axial direction, and is incident on the reflective liquid crystal element 61. The optical axis system of the retardation plate 63 whose axis direction is inclined is arranged in a plane vibrated by the incident S-polarized light. The retardation plate 63 having a tilt axis is a substrate in which a disc-shaped liquid crystal is disclosed in, for example, Japanese Patent Laid-Open No. 9-1 97397 or Japanese Patent Laid-Open No. 2000-32 1 576. The ideal form of this retardation plate 63 is as follows. -24-(21) (21) 200400378 (1) The retardation plate 63 is formed of an optically anisotropic layer formed by a transparent substrate (transparent support) and a compound having a dish-shaped structure unit arranged on the substrate . (2) The disc surface of the disc-shaped structural unit of the optical anisotropic layer is inclined to the transparent support surface, and the angle formed by the disc surface of the disc-shaped structural unit and the transparent support surface will be in the optical anisotropic layer Make a difference. (3) The total absolute retardation 延迟 Rel of the optical compensation sheet represented by the formula ② and the absolute 値 Re2 of the retardation of the liquid crystal layer represented by the formula ③ can satisfy the relationship of the following formula (formula): 0. 4x Re2 ^ Rel ^ l. Ox Re2 Φ [However, the delay of the above optical compensation sheet is defined by the following formula, {nl- (n2 + n3) / 2} xd ② (In the above formula, η 1, η 2 and η 3 represent the above optical compensation The refractive index in the triaxial direction of the sheet, each having a small refractive index in this order, d represents the thickness of the optical conversion sheet in terms of nm), and the retardation of the liquid crystal layer is defined by the following formula, {m 3- (m 1 + m 2) / 2} X d '③ (In the above formula, ml, m2 and m3 represent the three-axis refractive index of the above-mentioned liquid crystal, and each has a small refractive index in order, cT represents the above-mentioned liquid crystal Layer thickness in nm)]. -25- (22) (22) 200400378 When referring back to FIG. 8 for explanation, the light incident on the reflective liquid crystal element 61 will pass through the liquid crystal layer 66 and be reflected by the reflective electrode on the reflective substrate 65, and further The light is emitted through the liquid crystal layer 66 and the transparent substrate 64 and is incident on the second polarizing plate (analyzer polarizer) 6 2 b. On the other hand, when no electric field is applied to each pixel electrode and the liquid crystal layer 66 is disconnected, the polarization of the incident light remains unchanged and is reflected on the reflective substrate 65 as it is. The reflected light at this time is absorbed by the second polarizing plate (analytical polarizer) 6 2 b disposed on the front side of the projection lens 67. Therefore, as shown in FIG. 8 (A), it will not be incident.于 Projection Lens 6 7. That is to achieve black display. On the other hand, when an electric field is applied to each pixel electrode to drive the liquid crystal layer 66 to turn on, the polarization state of the incident light of the reflective liquid crystal element 61 is rotated and reflected on the reflective substrate 65. At this time, as shown in FIG. 8 (B), the reflected light passes through the second polarizing plate (analyzer) 62b and is projected through a projection lens 67 on a screen (not shown). A description will be given by taking the case where the tilt angle of the liquid crystal layer 66 is 85 degrees as an example. As the characteristics of the inclined axis retardation plate 63, a substrate-side angle of 4 degrees, a surface-side angle of 80 degrees, and a retardation in the direction of the film surface of about 107 nm will be used. The change in transmittance with respect to the plane angle in the axial direction including only the retardation plate having the inclined axis is shown in FIG. 9. In the figure, the vertical axis shows the transmittance and the horizontal axis shows the polar angle. As shown in the figure, near the polar angle of -55 degrees, it has the characteristic that the maximum transmittance is displayed. The S-polarized light is incident from the substrate side. The actual system using this phase difference plate 63 is simulated to obtain the visible angle characteristics shown in Figure 10. It can be seen that the black level becomes smaller near the azimuth angle of 90 ° and the polar angle of 15 to 20 degrees. . The light angle of the -26- (23) (23) 200400378 for the liquid crystal layer 66 is about 12 degrees, and the F 値 of the projection lens is 2. 4 (At this time, the angle taken into the lens is about 12 degrees, so that when the visible angle, the polar angle is 0 ~ 24 degrees, and the azimuth angle is in the range of 78 ~ 102 degrees.) The contrast becomes 1 000: 1, and there is no left and right contrast tilt, but it can become a uniform display. No interference caused by reflections on the surface or inside the interface was observed. Furthermore, the tilt direction of the liquid crystal when vertically aligning liquid crystals with negative electrical boundary anisotropy is set to an azimuth angle (45 + 90X η) [but η is an integer angle] for incident polarized light, which will cause an applied voltage The brightness becomes the brightest in liquid crystal. However, compared with 45 and 135 degrees, 45 and 225 degrees, or 45 and 3 15 degrees, the black level is lowered, so it is more ideal. The retardation of the above optical compensation sheet is defined by the above-mentioned ②, and the retardation Rel thereof is 107 nm. The retardation of the liquid crystal layer is defined by the aforementioned formula (3). At this time, Re2 is 267 nm. Rel is 0 of Re2. 40 times. In Figure 1 1 (A) ~ (G), Rel / Re2 = 0 will be displayed. 13 ~ 0. Visible angle characteristic chart at 8 o'clock, this ratio 値 has no effect if it is small, but the temple will become poor because of it, so it is ideally 0. 2 ~ 0. 5 range. When the pre-tilt angle of Cheng Chang is 85 degrees and the azimuth angle of the liquid crystal is 45 degrees, the retardation Re2 of the liquid crystal is 267 nm. Under this condition, the optimum retardation Rel of the retardation plate having negative optical uniaxial anisotropy is 86 nm. The incident light is P-polarized light. Next, in the third embodiment, when the phase difference plate 63 whose axis direction is inclined is not inserted, it is set as a second comparative example. The other optical arrangements are the same as those in the third embodiment and the first comparative example. In the actual -27- (24) (24) 200400378 projected image, the tilt of the black level in the left and right directions was observed. Whereas the contrast is high, it is 700: 1, but at the low level it is 3 00: 1. However, no interference caused by reflections on the surface or inside the interface was observed. The visible angle characteristics of the second comparative example are shown in FIG. 12. From the visible angle characteristics shown in Fig. 12, it can be seen that, when no voltage is applied to the black display of the liquid crystal, if there is a tilt angle of the liquid crystal, the position where the contrast can be obtained is in the center, although in the polarization direction and its positive direction. There will be a high contrast in the intersection direction, but for the polarization direction, especially the light with an incident angle from a 45-degree oblique direction, the light will leak quickly to increase the black level and reduce the contrast. When viewing at an azimuth angle of 90 degrees (equivalent to an incident angle of 270 degrees below the oblique angle), if the polar angle becomes small (when the light is incident obliquely), the change corresponding to the displacement of the azimuth angle can be detected. Black level. This condition means that there is a black level tilt in the left and right directions on the projected screen. This phenomenon is caused by the fact that the characteristics of the three reflection-type LCD screens are not consistent during color synthesis, which makes the observation uneven and extremely significant. For this state, the third embodiment uses S-polarized light as the incident light, and has a negative uniaxial anisotropy optically, and the retardation plate 63 which is inclined obliquely and orthogonal to the incident S The polarized aurora's vibrating side becomes parallel, and as shown in the visible angle characteristic of FIG. 10, the black level will be reduced, and the contrast will be increased, so that the range of angles from which the contrast can be obtained can be expanded. Next, a fourth embodiment of the present invention will be described with reference to FIG. 13. Figures 13 (A) and (B) are structural diagrams showing a fourth embodiment of a second embodiment using a reflection type B? Projection apparatus according to one embodiment of the present invention when displaying in black and white. As shown in FIGS. 13 (A) and (B), the projection device 70 using the reflective liquid crystal element according to the fourth to twenty-eighth (25) (25) 200400378 embodiments of the present invention is provided with a polarizer that takes out linearly polarized aurora from the incident light. The reflector 72a is provided on the light path of the incident light incident on the reflective liquid crystal element 71, and on the light path of the reflected light emitted from the reflective liquid crystal element 71. The second polarizing plate (analytical polarizer 72b.) The reflective liquid crystal element 71 has a transparent substrate 74 and a reflective substrate 75 arranged opposite to each other, and has a liquid crystal layer 76 interposed therebetween. As shown in the figure, a transparent electrode having a common electrode is formed on the opposite surface of the transparent substrate 74, and a driving circuit such as a MOS transistor or a TFT formed for each pixel is formed on the opposite surface of the reflective substrate 75, and a reflection is formed. The electrodes are formed into a plurality of matrices. As the pixel size, minute pixels of, for example, about 10μίΏΧΙΟμίΉ are formed. As the liquid crystal molecules constituting the liquid crystal layer 76, a negative dielectric anisotropy having a vertical alignment type will be used. Nematic liquid crystal. The surfaces of the transparent substrate 74 and the reflective substrate 75 that are in contact with the liquid crystal layer 76 are formed with an alignment film (not shown) made of a silicon oxide, for example, in order to impart alignment to the liquid crystal molecules. The liquid crystal molecules in the state are given, for example, two azimuth angles of about 80 to 89 degrees of inclination and about 45 degrees to the polarizing axis of the polarizing plate. Fig. 1 (A) shows a state where no electric field is applied to each pixel electrode. The bottom (initial state) will show the normal black (NB) mode. Figure 13 (B) shows a white mode. Next, the fourth embodiment of the present invention will be described. Figures 13 (A), (B), The light emitted from an unillustrated light source is first separated into the three primary colors of RGB by a color separation optical system (not shown), and then only -29- (26) (26) 200400378 is taken out by the first polarizing plate 72a. P is polarized and enters the reflective liquid crystal element 71. The light incident on the reflective liquid crystal element 71 passes through the liquid crystal layer 76 and is reflected by the reflective electrode on the reflective substrate 75, and then passes through the liquid crystal layer 76 and transparent. After the substrate 74 comes out, the phase is inclined in the axial direction The retardation plate 73 is adjusted. The optical axis of the retardation plate 73 whose axis direction is inclined will arrange the P polarized polarized light incident on the surface to be vibrated. The retardation plate 73 having an oblique axis will be arranged, for example, on The disc-shaped liquid crystal disclosed in Japanese Patent Laid-Open No. 9-1 97397 or Japanese Patent Laid-Open No. 2000-321 576 on a substrate, etc. The P-polarized polarized light passing through the retardation plate 73 is incident on the second polarization. Plate (analytical polarizer) 72b. If the electric field is not applied to each pixel electrode and the liquid crystal layer 76 is disconnected at this time, the polarization state of the incident light is maintained and reflected by the reflective electrode plate 75. At this time, the reflected light is absorbed by the second polarizing plate (analytical polarizer) 72b provided in front of the projection lens 77, so that it is formed as shown in FIG. 13 (A), and does not enter the projection lens. 77. That is to achieve black display. On the other hand, when an electric field is applied to the pixel electrodes and the liquid crystal layer 76 is driven to be turned on, the polarization state of the incident light of the reflective liquid crystal element 71 is rotated and reflected on the reflective electrode plate 75. At this time, as shown in FIG. 13 (B), the reflected light passes through the second polarizing plate (analytical polarizer) 72b and is projected by a projection lens 77 on a screen (not shown). The state at a pre-tilt angle of 85 degrees of the liquid crystal layer 76 will be described as an example. As the characteristics of the retardation plate 73 having an inclined axis, for example, a substrate-side angle of 4 degrees, a surface-side angle of 80 degrees, a retardation of the film surface direction of about 142 nm, and an azimuth angle of 270 degrees are used. On the other hand, the light incident on the retardation plate 73 is incident from the side where the inclination angle is large. -30- (27) 200400378 Fig. 14 (A) shows the plane direction of the liquid crystal alignment direction Π of the optical axis I of the retardation plate 73 and the reflective liquid crystal element 7 in the fourth embodiment of the present invention, as viewed from the plane direction. (D) shows the relationship between the structure of the fourth embodiment, the direction of incident light vibration, and the direction of liquid crystal alignment when viewed from the cross-sectional direction of the reflective liquid crystal element 71, the retardation plate 73, and the like. B) shows the detailed structure of the phase difference plate 73 in the same figure (D). As shown in FIG. 14 (D), the light incident on the first polarizing plate 72a will take out the P polarized aurora vibrating on the vibration plane m parallel to the paper surface and enter the liquid crystal alignment direction (the liquid crystal azimuth angle is 45 degrees). ) Π of the reflective liquid crystal element 71. The light reflected by the reflective liquid crystal element 71 is incident on the retardation plate 73. The retardation plate 73 is shown in FIG. 14 (B) as enlarged. When it is composed of disc-shaped liquid crystal molecules, the liquid crystal molecules are arranged as shown in FIG. 7 and the optical axis is arranged as In the direction indicated by arrow mark 77. The polarized light of the transmission phase difference plate 73 is transmitted by the second polarizing plate 72b to an S-polarized light that vibrates in a direction perpendicular to the paper surface. The actual system using this retardation plate 73 is used to simulate the visible angle characteristics obtained as shown in FIG. 14C. It can be seen that the black level will become around the azimuth angle of 90 degrees and the polar angle of 15 to 20 degrees. small. The incident angle of the light incident on the liquid crystal layer 76 is about 12 degrees, and F 値 2 of the projection lens. 4 (Because the lens takes in an angle of about 12 degrees at this time, it will take in light in the range of 0 to 24 degrees in the visible angle and 78 to 102 degrees in the azimuth). The contrast when projected on the screen is approximately 1 000: 1 and can display uniform display without left and right contrast tilt. No interference caused by reflections on the surface or inside the interface was observed. Next, a fifth embodiment of the present invention will be described with reference to Figs. Figures -31-(28) (28) 200400378 1 5 (D) is a structural view showing a main part of a fifth embodiment of a projection device using a reflective liquid crystal element according to an embodiment of the present invention. In the same figure (D), the same structural parts as those in FIGS. 13 and 14 (D) will be assigned the same symbols and their descriptions will be omitted. In the embodiment shown in FIG. 15 (D), when compared with the fourth embodiment, a retardation plate 81 having a tilted axis is provided. The reflected light from the reflective liquid crystal element 71 having a liquid crystal azimuth angle of 45 ° to The second polarizing plate 72b has the same optical path. However, the optical axis of the retardation plate 81 is shown as I in FIG. 15 (A), and its structure is as shown in FIG. 82 (B), where the optical axis is from the surface side toward the substrate side, and has a dish shape. The arrangement of the disc-shaped liquid crystal molecules 83 of the liquid crystal is different from that of the fourth embodiment. Here, the case where the pretilt angle of the liquid crystal layer 76 is 85 degrees will be described as an example. As the characteristics of the retardation plate 81 having an inclined axis, for example, a light emitting side angle of 80, a light incident side angle of 4 degrees, and a retardation in the film surface direction of about 107 nm will be used. In this embodiment, the light incident on the retardation plate 81 is incident from a small side inclined. In the actual system using the phase difference plate 81, the visible angle characteristics obtained by simulation are shown in Fig. 15 (C). The comparison is in the vicinity of an azimuth angle of 90 degrees and a polar angle of 15 to 20 degrees. It can be seen that there is some improvement, and the contrast when projected on the screen is about 6 5 0: 1, and no left and right unevenness or interference stripes are seen. Next, a sixth embodiment of the present invention will be described with reference to Figs. Fig. 16 (C) is a structural diagram showing a main part of a sixth embodiment of a projection device using a reflective liquid crystal element according to an embodiment of the present invention. In the same figure (C), for the parts having the same structure as those in FIGS. 8 (A) and (B), the same symbols will be attached and the description will be omitted. The sixth embodiment shown in FIG. 16 (C) is characterized in that -32- (29) (29) 200400378 is provided in the second embodiment according to the third embodiment. 1 a polarizing plate 6 2 a to a reflective liquid crystal element 61 1 and a retardation plate 63 incident on the incident light path of the reflective liquid crystal element 61 1, and a retardation plate 86 is provided from the reflective liquid crystal element 6 1 to The reflected light path of the reflective liquid crystal element 61 of the second polarizing plate 6 2 b. The structure other than the retardation plate 86 is the same as that of the third embodiment. That is, the first polarizing plate 62a is as shown in FIG. 16 (C), and only the S-polarized aurora whose vibration direction is perpendicular to the paper surface direction is taken out, and the second polarizing plate 62b is as shown in FIG. 16 (C). Only the P-polarized aurora whose vibration direction is parallel to the paper surface direction is allowed to pass. The liquid crystal alignment direction of the reflective liquid crystal element 61 is shown in FIG. 16 (A) as azimuth angle 225 degrees, and the optical axis of the retardation plate 86 is shown as I in the same figure (A). As for the retardation plate 86 whose axis is inclined, the optical axis is directed from the surface side toward the substrate side as shown in 87 in FIG. 16 (C). As a characteristic, for example, the angle of the light exit side is 4 degrees. The incident side angle is 80 degrees, and the retardation in the film surface direction is about 107 nm. However, in an actual system using the phase difference plate 86, the visible angle characteristics obtained by simulation are shown in FIG. 16 (B), and the improvement in the azimuth angle 90 degrees and the angle 15 ~ The contrast around 20 degrees, and the contrast when projected on the screen is about 20: 1. However, no left-right unevenness or interference fringes are seen. Next, a seventh embodiment of the present invention will be described with reference to FIG. 17. Fig. 17 (C) is a structural diagram showing a main part of a seventh embodiment of a projection device using a reflective liquid crystal element according to an embodiment of the present invention. In the same figure (C), for the same structural parts as in Figure 16 (C), the same symbols will be attached and the description will be omitted -33- (30) 200400378. In the seventh embodiment shown in FIG. 17 (C), when compared with the sixth embodiment described above, the retardation plate 91 provided with a tilted axis is a reflective liquid crystal element 61 from a liquid crystal azimuth angle of 22 °. The reflected light is the same on the optical path of the second polarizing plate 6 2b, but is arranged on the optical axis of the retardation plate 9 1 of the retardation plate shown by V in FIG. 17 (A), and the disk The method of forming the disc-shaped liquid crystal molecules of the liquid crystal is different from that of the sixth embodiment. Here, the phase difference plate 91 whose axis is inclined is to make the optical axis from the surface side to the substrate side as shown in FIG. 17 (C) and 9 2 as another characteristic. For example, the light exit side is used. The angle is 4 degrees, the angle of the light incident side is 80 degrees, and the retardation in the direction of the film surface is about 107 nm, which is the same as the phase plate 86 of the sixth embodiment, but the azimuth angle to the phase difference plate 86 is 270 degrees, and The phase difference plate 91 has a difference in azimuth angle of 90 degrees. In an actual system using the phase difference plate 91, the visible angle characteristic obtained by simulation is shown in FIG. 17 (B). The contrast near the azimuth angle of 90 degrees and the polar angle of 15 to 20 degrees is almost visible. Although it is not improved, although the contrast when projected on the screen is about 5: 1, the left and right unevenness or interference fringes are not seen. Next, an eighth embodiment of the present invention will be described with reference to FIG. 18 . Fig. 18 (C) is a structural diagram showing a main part of an eighth embodiment of a projection device using a reflective liquid crystal element according to an embodiment of the present invention. In the same figure (C), for the parts having the same structure as those in FIG. 14 (D), the same reference numerals will be attached and descriptions thereof will be omitted. The eighth embodiment shown in FIG. 18 (C) is characterized in that a phase difference plate 95 is provided in place of the phase difference plate 73 of the fourth embodiment shown in FIG. M in the example of the second embodiment. Place. The phase difference plate 9S order -34- (31) 200400378 shows the optical axis from the surface side (light incident side) toward the substrate side (light exit side) as shown in Fig. 18 (C) and 96, and it also has its characteristics. For example, if the substrate side angle is 80 degrees, the surface side angle is 4 degrees, and the retardation in the film surface direction is about 107 nm, the light system incident on the retardation plate 95 is different from the retardation plate 73, but It is incident from the side where the inclination angle is smaller. Fig. 18 (A) shows the relationship between the optical axis I of the retardation plate 95 and the liquid crystal alignment direction Π of the reflective liquid crystal element 71. In an actual system using the phase difference plate 95, the visible angle characteristic obtained by simulation is shown in FIG. 18 (B), and an improvement can be seen near an azimuth angle of 90 degrees and a polar angle of 15 to 20 degrees. Contrast, and the contrast when projected on the screen is about 600: 1, and no unevenness or interference fringes are seen. Next, a ninth embodiment of the present invention will be described with reference to FIG. 19. Fig. 19 (C) is a structural view showing a main part of a ninth embodiment of a projection device using a reflective liquid crystal element according to an embodiment of the present invention. In the same figure (C), the same components as those in FIG. 18 (C) are denoted by the same symbols and their explanations are omitted. The ninth embodiment shown in FIG. 19 (C), when compared with the eighth embodiment shown in FIG. 18 of the embodiment related to the second embodiment, is characterized in that it is used instead of the eighth embodiment. Where the reflective liquid crystal element 71 is used, the reflective liquid crystal element 61 is used. The other connections are the same as those in the eighth embodiment. FIG. 19 (A) shows the relationship between the optical axis I of the connector 95 and the liquid crystal alignment direction VI of the reflective liquid crystal element 61 in the ninth embodiment. In the actual system using the phase difference plate 95, 'the visible angle characteristic obtained by the simulation is shown in Fig. 19 (B)', it can be seen that there is an improvement in the azimuth angle 9 0 -35- (32 ) (32) 200400378 degrees Contrast near polar angle I5 ~ 20 degrees. As for the contrast when projected on the screen, it is about 600: 1 the same as that of the 8th embodiment, and no unevenness or interference on the left and right is seen. stripe. The characteristics of the first to ninth embodiments and the first comparative example, and the obtained performances are aggregated and shown in FIG. 20. In the figure, c R is the contrast ratio (Contrast Ratio), that is, the brightness ratio of white display and black display. The polarizing plate angle is such that when the incident plane of the reflective liquid crystal element is the plane of the X axis and the Y axis, and the X axis of the horizontal direction is used as a reference, it is rotated in a counterclockwise direction as a positive angle, and the incident light is linearly deflected. In the case of aurora, the angle of the angle formed by the surface element including the vibration direction is calculated from the X direction on the element surface. Therefore, when P polarized aurora incident from the 270-degree azimuth (from obliquely below), the light will vibrate in parallel with the incident surface, so the angle formed with the X axis, that is, the angle of the polarized plane will become 9 0 °. Fig. 21 shows examples of retardation plates, polarizing plates, and incident light whose axes are inclined. In FIGS. 21 (A) to (E), the retardation plate 101 shows any one of the retardation plates 53, 63, 73, 81, 86, 91, 95 of the aforementioned first to ninth embodiments, and It is shown in a pattern that the dish-shaped liquid crystal molecules are arranged in an inclined manner in the thickness direction of the film surface. That is, the retardation plate 1 〇1 (5 3, 6 3, 7 3, 8 1, 8 6, 9 1, 9 5) means that its optical axis is parallel to the paper surface in FIG. It is inclined, and corresponds to the thickness from the film surface, so that the tilt angle of the optical axis gradually changes. The polarizing plates 102, 104, 105, and 106 are equivalent to the aforementioned first polarizing plate 62a or second polarizing plates 62b, 72b. -36- (33) (33) 200400378 Figure 2 1 (A) shows that a polarizing plate 102 with transmissive S polarized light is provided on the light incident side or light exit side of the retardation plate 1 0 1 and As shown in FIG. 10, light forms an example that can be incident at an angle that completely crosses the dish-shaped liquid crystal molecules of the retardation plate 101. This first example is an example in which an optimal contrast ratio (contrast coefficient) can be obtained, and corresponds to the third and fourth embodiments described above. At this time, the optical axis of the retardation plate is parallel to the paper surface, and the transmission axis of the polarizing plate 102, which can only transmit S polarized light, is perpendicular to the paper surface, and the two are orthogonal to each other (perpendicularly perpendicular to each other). Fig. 2 1 (B) shows that a polarizing plate 1 04 having transmissive S polarized light characteristics is provided on the light incident side or light exit side of the retardation plate 1 0 1, and the light is as follows: An example in which it can be incident at an angle that completely crosses the dish-shaped liquid crystal molecules of the retardation plate 101. However, in this example, the arrangement of the dish-shaped liquid crystal molecules of the polarizing plate 104 and the retardation plate 101 is roughly parallel to the surface, which is different from the first example shown in FIG. 2 (A). Differently, this second example is an example of obtaining an ideal contrast ratio, which is equivalent to the aforementioned fifth, eighth, and ninth embodiments. Fig. 2 1 (C) shows that a polarizing plate 1 with a transmissive P polarization feature is provided on the light incident side or light exit side of the retardation plate 1 〇1, and the light is shown as 103 The third example is a non-ideal example in which a sufficient contrast ratio cannot be obtained, and it can be incident at the angle of the dish-shaped liquid crystal molecules that completely traverse the retardation plate 101. It is equivalent to the sixth embodiment described above. example. In addition, FIG. 21 (D) shows that a polarizing plate 1 06 having transmissive S polarized light or P polarized light is provided on the light incident side or light outgoing side of the retardation plate 1 0 1 ′, and the light is as shown in 107 As shown in the figure, an example in which the plate-shaped liquid crystal molecules at the angle of -37-(34) (34) 200400378 of the retardation plate 101 cannot be completely crossed is incident. This fourth example is the least desirable example in which the contrast ratio cannot be obtained, and corresponds to the aforementioned seventh embodiment. The 21 (E) display shows that a polarizing plate 1 0 5 having transmissive P polarized light is provided on the light incident side of the retardation plate 1 0 1, and the light is formed as shown in FIG. An example of incident through the angle of the dish-shaped liquid crystal molecules of the retardation plate 101. This fifth example is an example in which an ideal contrast ratio can be obtained, and corresponds to the first and second embodiments described above. As mentioned above, in the third, fourth, fifth, eighth, and ninth embodiments described above, the S-polarized light is used for the incident light of the retardation plate, and the optical property has negative uniaxial anisotropy. The phase difference plate 101 (63, 73, 81, 95) which is inclined obliquely is formed to be parallel to a plane orthogonal to the direction of the incident polarized light vibration. Therefore, the black level can be reduced, and the contrast can be improved. This makes it possible to expand the angle range in which the contrast ratio can be sufficiently obtained. In the above embodiments, only the phase difference plate structure having a tilt axis is described in a state where the tilt angles of the light incident side and the light exit side are different. However, in the following tenth to twenty-ninth embodiments, the structure of the retardation plate shows a good condition even if the same inclination angle is formed on the incident side and the outgoing side of the light. When the tenth to twenty-ninth embodiments are limited by limiting the pre-tilt angle of the liquid crystal, it becomes as shown in FIG. For comparison, Fig. 22 shows the second comparative example, the third example, and the fourth example. The tenth to twelfth embodiments of FIG. 22 transmit light from the color separation light source through the color separation means for color separation of the three primary colors of RGB, and then transmit the light through the first polarizing plate to irradiate the liquid crystal held by the transparent A reflective liquid crystal element formed between a substrate and an active matrix substrate (reflective substrate). Next, the light modulated by -38- (35) (35) 200400378 corresponding to the image data to be displayed on the reflective liquid crystal element is arranged in an orthogonal Nicol relationship with the first polarizing plate. An example of the configuration of a projection device having an oblique projection optical system (off-axis) after the second polarizing plate has polarized the aurora and enlarged by a projection lens. A retardation plate having uniaxial anisotropy and an optical axis inclined obliquely is inserted between the reflective liquid crystal element and the second polarizing plate. The liquid crystal layer of the reflective liquid crystal element has a pre-tilt angle of 85 degrees. The azimuth is 45 degrees. The structure in which the second polarizing plate can transmit the S-polarized light is common to a reflective liquid crystal element in which the P-polarized light is incident. The phase difference plate having an inclined axis described above in each embodiment has an angle on the substrate side (light emitting side) and an angle on the surface side (light incident side), but is configured to have a different angle in each embodiment (50 degrees, 40 degrees or 30 degrees). However, the azimuth angle of the phase difference plate is 270 degrees. In the 13th and 14th embodiments, the angles of the substrate side (light exit side) and the surface side (light incident side) of the retardation plate are 10 degrees and 70 degrees, or 70 degrees and 10 degrees, respectively. This is different from the tenth to twelfth embodiments. In the tenth to fourteenth embodiments, there is no left and right contrast inclination, and a uniform display can be displayed, and no interference fringe is observed. As shown in FIG. 22, in the fifteenth to twenty-sixth embodiments, a projection device having the above-mentioned oblique projection optical system (off-axis) is inserted with a uniaxial anisotropy and its optical axis is inclined obliquely. The difference plate is between the first polarizing plate and the reflective liquid crystal element, and the pre-tilt angle of the liquid crystal layer of the reflective liquid crystal element is 85 degrees, the azimuth angle of the liquid crystal is 225 degrees, and the S polarized light is incident on the reflective liquid crystal element. Although the structure of the second polarizing plate that can transmit P polarized light is common, the pre-tilt angle, retardation, and pre-tilt of the retardation plate on the incident side are different -39- (36) (36) 200400378. That is, in the 15th to 18th embodiments' of the retardation plate, the incident side pre-tilt angle and the exit side pre-tilt angle are both 50 degrees, but the delays are different from each other. The pre-tilt angle on the incident side and the pre-tilt angle on the exit side of the retardation plate of the nineteenth to twenty-sixth embodiments are the same in each example, but their angles will differ by 10 degrees in each embodiment. Until 80 degrees. Furthermore, in the second to seventh embodiments, the pre-tilt angle on the incident side and the pre-tilt angle on the exit side of the retardation plate are both 70 degrees, but the pre-tilt angle of the liquid crystal layer of the reflective liquid crystal element. It is 80 degrees in the 27th embodiment, 83 degrees in the 28th embodiment, and 89 degrees in the 29th embodiment. As a result of these states, it was found that when the pre-tilt angle of the liquid crystal layer of the reflective liquid crystal element is greater than 89 degrees, when the electric field is applied to the pixel electrode, the tilt directions of the liquid crystal molecules become scattered and different, so that it is easy to produce Image defects, and when the pre-tilt angle of the liquid crystal layer of the reflective liquid crystal element is 83 degrees or less, even if a phase difference plate with a tilt axis is used to compensate, the contrast cannot be obtained, and at the same time, the left and right deviations of the contrast will occur. (Uneven) feelings. Therefore, the pre-tilt angle of the liquid crystal layer of the reflective liquid crystal element is desirably between 83 degrees and 89 degrees. Next, a third embodiment of the present invention will be described with reference to FIG. 23. Figures 23 (A), (B), and (C) each show a front view, a longitudinal sectional view, and a side sectional view of a main part of a third embodiment of the present invention. In the same figures (A) to (C), one side of the retardation plate 1 1 1 is adhered to the polarizing plate 1 1 3 by an adhesive layer 1 12, and the other side of the retardation plate 1 1 1 is The surface is adhered to the back surface of the glass layer 1 1 5 by the adhesive layer 1 1 4. On the surface of the glass layer 1 1 5, -40- (37) (37) 200400378 is formed with an anti-reflection layer 1 1 6. The retardation plate 1 1 1 has a dish-shaped liquid crystal as a basic negative uniaxial anisotropy, and its optical axis system is shown as a schematic display in FIG. 23 (B), which is inclined to the mold surface and parallel to the paper surface. As for the transmission axis of the polarizing plate 1 I3, as shown in FIG. 23 (A), the transmission axis is oriented up and down in the figure, that is, it is orthogonal to the optical axis of the retardation plate 1 1 1. According to the third embodiment, since the retardation plate 1 1 1 is configured to be 30% of the polarizing plate 1 13 so as not to have unnecessary surface reflection, it has a so-called feature of improving transmittance. Further, at this time, the joining direction of the polarizing plate 1 1 3 and the retardation plate can be clearly defined. When the pre-tilt angles of the dish-shaped liquid crystals are different from each other above and below the phase difference plate 1 1 1, the side with the larger tilt angle is caused to stick to the polarizing plate 1 1 3. Furthermore, it is desirable that the transmission axis of the polarizing plate 1 1 3 and the optical axis of the retardation plate 1 1 1 can be on the same plane. As shown in FIG. 23, since the surface of the retardation plate 1 1 1 is adhered by the glass layer 115 and the adhesive layer 114 that are subjected to anti-reflection treatment, the excess interface reflection can be reduced. As a result, a bright projection. It can also suppress the refracted surface caused by the surface concavity and produce unclear and distorted (distorted) images. Figures 24 (A) and (B) are diagrams showing the structure of a fourth embodiment of a projection device using a reflective liquid crystal element according to an embodiment of the present invention in black display and white display. As shown in FIGS. 24 (A) and (B), a projection device 3 50 using a reflective liquid crystal element according to a fourth embodiment of the present invention is provided with a first polarizing plate 352a for taking out linear polarized light from incident light, and incident on the incident light. On the light path of the incident light of the reflective liquid crystal element 3 5 1 and on the light path of the reflected light from the reflective liquid crystal element 3 5 1, a retardation plate 3 5 3 -41 having an inclined structure in the axial direction is provided. -(38) (38) 200400378 and the second polarizing plate (analyzer) 352b. The second polarizing plate 352b is disposed so as to have a cross-Nicol relationship with respect to the single polarizing plate 352a. The reflective liquid crystal element 351 has a structure in which a transparent substrate 354 and a reflective substrate 3 5 5 are arranged to face each other, and a liquid crystal layer 3 5 6 is interposed therebetween. In addition, although not shown, a transparent electrode having a common electrode is formed on the opposite surface of the transparent substrate 354, and a MOS circuit formed on each pixel is formed on the opposite surface of the reflective substrate 355. A crystal, a driving circuit formed of a TFT, and the like and a plurality of reflective electrodes are formed in a matrix. As the pixel size, fine pixels of about 10 μm × 10 μm are formed. As the reflective liquid crystal elements (crystal grains) constituting the liquid crystal layer 3 to 56, the nematic liquid crystal is made to have a pre-tilt angle of 2 to 5 degrees, the twist angle of the liquid crystal layer is 80 to 90 degrees, and the transparent substrate 354 side The liquid crystal alignment azimuth has a range of 190 degrees to 200 degrees or 280 degrees to 290 degrees. Furthermore, in the fourth embodiment, the wavelength normalization delay using the liquid crystal layer 356 is 0. 35 or more 0. 55 or less. In addition, on the surfaces of the transparent substrate 354 and the reflective substrate 3 5 5 that are in contact with the liquid crystal layer 3 5 6, an alignment film (not shown), for example, frictionally coated with a polyimide resin surface, is formed to impart alignment to the liquid crystal molecules. ), And the liquid crystal molecules imparted to the initial state have, for example, a tilt angle of about 2 degrees to 5 degrees and a plane azimuth angle of about 190 degrees to 200 degrees, or 280 degrees to 290 degrees to the polarization axis of the polarizing plate. The twist angle of the liquid crystal is controlled from 80 degrees to 90 degrees. Fig. 24 (A) shows a state in which black is displayed when an electric field is applied to each pixel electrode and the liquid crystal layer 356 is driven to be turned on. 'The same figure (B) shows a state where no electric field is applied to each pixel. (In the initial state) -42- (39) (39) 200400378 white normal white (MW) mode is displayed, and the liquid crystal layer 356 is open. Next, the fourth embodiment will be described with reference to Figs. Fig. 25 (B) shows the structure of Fig. 24 (A) and (B) together with the optical axis of the retardation plate 353, and the same parts as those of Fig. 24 (A) and (B) are attached with the same symbols. In FIGS. 24 (A), (B), and FIG. 25 (B), the light emitted from a light source not shown is first taken out by the first polarizing plate 352a with only p-polarized light incident on the reflective liquid crystal element. 351. FIG. 25A shows the vibration direction of the P-polarized polarized light entering the reflective liquid crystal element 351 when it is taken out from the first polarizing plate 3 52a. In the reflective liquid crystal element 3 5 1, the alignment direction of the liquid crystal molecules of the liquid crystal layer 3 5 6 is formed on the light incident side as the direction indicated by Π in FIG. 25 (A), and the reflective surface side is formed in FIG. 25 ( A) Direction indicated by m. The light incident on the reflective liquid crystal element 351 will pass through the liquid crystal layer 3 5 6 and be reflected by the reflective electrode on the reflective substrate 3 5 5, and then exit through the liquid crystal layer 3 5 6 and the transparent substrate 3 5 4 again, and It is incident on the retardation plate 3 5 3 inclined in the axial direction. As for the retardation plate 3 5 3 inclined in the axial direction, as shown in IV in FIG. 25 (A), it is arranged so as to be aligned in parallel with the direction in which the incident P-polarized light vibrates. That is, the optical axis system of the retardation plate 3 5 3 is set to be orthogonal to the transmission axis of the first polarizing plate 3 5 2a. The light modulated by the retardation plate 3 5 3 having a tilt in the axial direction of the optical axis shown in Figure 359 in FIG. 25 (B) enters the second polarizing plate (analyzer) 352b. The polarizing direction of the second polarizing plate (polarizing polarizer) 352b is indicated by V in FIG. 25 (A). When an electric field is not applied to each pixel electrode or a threshold voltage is applied to the liquid crystal layer 3 5 6 to form an open circuit (OFF), the incident polarized polarized light will be -43- (40) (40) 200400378 in the reflective type. The liquid crystal element 3 5 1 is modulated, and the polarization state is rotated to emit, and as shown in FIG. 24 (B), it passes through the second polarizing plate (analyzer) 3 5 2b and passes through the lens 3 5 7 Enlarge and project on a screen (not shown). On the other hand, when a sufficient electric field is applied to each pixel electrode to drive the liquid crystal layer 3 56 to be turned on, the polarization state of the incident light will remain unchanged and be reflected by the reflective substrate 3 5 5 as it is. At this time, the reflected light is absorbed by the second polarizing plate (analytical polarizer) 352b provided in front of the projection lens 3 57. Therefore, as shown in FIG. 24 (A), it is not incident on the projection Lens 3 57. This will display black. Next, the phase difference plate 353 having a tilt axis will be described in more detail. The phase difference plate 3 5 3 having a tilt axis uses, for example, a negative birefringence compensation plate disclosed in the specification of U.S. Patent No. 54 1 0422, or two axes. The stretched polymer film is disclosed in Japanese Unexamined Patent Application Publication No. 9-1 97379 or Japanese Unexamined Patent Application Publication No. 2000-32 1 576 on a substrate. The ideal form of this retardation plate 3 5 3 is as follows. (1) The retardation plate 3 53 is composed of a transparent substrate (transparent support) and an optically anisotropic layer made of a compound having a dish-shaped structural unit disposed on the transparent substrate (transparent support). (2) The disc surface of the disc-shaped structural unit of the optically anisotropic layer is inclined to the transparent support surface, and the angle formed by the disc surface of the disc-shaped structural unit and the transparent support surface is toward the optical anisotropy The layer depth direction changes. (3) The total absolute 値 R e 1 of all the retardations of the optical compensation sheet expressed by the formula ⑤, and the absolute 値 R e 2 of the retardation of the liquid crystal layer expressed by the formula ⑥ can satisfy -44- (41) 200400378 The following ④ The relationship of the formula is 0.15χ Re2S Rel $ 〇. 6x Re2 ④ [However, the delay system of the optical compensation sheet is defined as follows, [η 1-(n2 + n3) / 2] X d ⑤ (In the above formula, nl, η2, η3 represent the three axes of the optical compensation sheet Directional refractive index, and each has a small refractive index in this order, and d is the thickness in terms of nm of the optical compensation sheet), and the retardation of the liquid crystal layer is defined as follows, {m3- (m 1 + m2) / 2} xd " ⑥ (In the above formula, m 1, m 2, m 3 represents the triaxial refractive index of the liquid crystal layer, and each has a small refractive index in this order, and d > represents the above liquid crystal Layer thickness in nm)]. As the characteristics of the retardation plate 353 having an inclined axis, for example, a substrate-side angle of 4 degrees, a surface-side angle of 80 degrees, and a retardation in the film surface direction of about 107 nm are used. The light incident on the retardation plate 3 5 3 is incident from the side where the inclination angle is large. The actual system using this phase difference plate 3 5 3, the visible angle characteristics obtained by simulation are shown in Figure 2 5 (C), from the azimuth angle of 90 degrees -45-(42) (42) 200400378 When viewed from the direction, the black color sinks (the light intensity is very low when black is displayed). Therefore, when viewed from a polar angle of 10 to 30 degrees (looking at the light reflected from the oblique direction), the characteristics can be found to be excellent. . Here, 5V is applied to each pixel electrode in order to display a black color. Furthermore, in FIG. 25 (C), the circle with a dotted line (dotted line) is a circle with a polar angle of 20 degrees, and the circle with the smallest diameter is 20 degrees. Indicated by the ground) ° In this embodiment, the light intensity at the azimuth angle of 70 degrees to 110 degrees, and the polar angle of 0 degrees to 20 degrees, when 5V voltage is applied to each pixel electrode, becomes as in FIG. 26 is shown by VI, and in this angular range, the black level is extremely good, and it is confirmed that even oblique optical systems can obtain high contrast due to incident light incident obliquely. The incident angle of the light incident on the liquid crystal layer 3 5 6 is about 12 degrees, and the F 値 of the projection lens 3 5 7 is 2. 4 (At this time, the lens takes in an angle of about 12 degrees, so it can be taken into the range of 0 to 24 degrees of polar angle, 78 to 102 degrees of azimuth) when projected on the screen, the contrast is about 900: 1 Although there is a slight left-to-right contrast tilt, they are all in the practical range, and no interference fringes caused by reflections on the surface or inside the interface are observed. Next, the retardation plate 3 5 3 according to the fourth embodiment is removed, and the other optical arrangement is the same as that of the embodiment shown in FIG. 24 as a third comparative example. In the actually projected screen of the third comparative example, although the interference phenomenon caused by reflection on the surface or inside the interface was not observed, the phenomenon of tilt of the black level in the left-right direction can be seen. While the contrast of the formation is 500: 1, the low contrast is 1000: 1. It can also be seen that the angular characteristic is formed as shown in Fig. 27. Even when the -46- (43) (43) 200400378 is applied to the black display of the pixel electrode, the liquid crystal molecules near the substrate are affected by the alignment film. Keep it horizontal so that the contrast in a particular direction becomes poor. In this third comparative example, since the reflection-side substrate system is set to 5 degrees' and the transparent-electrode-side electrode plate system is set to 110 degrees, the range of azimuths from 0 to 90 degrees and 180 to 270 degrees can be detected. The black level becomes poor. The light intensity of the black display at the azimuth angles of 70 degrees to 110 degrees and polar angles of 0 degrees to 25 degrees in the third comparative example is shown in FIG. The polar angle is small (when it is not too inclined), although the black level is good, but as the polar angle becomes larger, especially when the azimuth is deflected from 90 degrees (at this time, it is assumed to be incident from a direction of 270 degrees State of light) to increase the light intensity quickly, which means that although black display is being performed, a good black level cannot be obtained. This situation means that on the projected screen, a black level is inclined to the left and right, so that it has a contrast that is left and right. And this phenomenon, when color synthesis is performed, because the characteristics of the three reflection type liquid crystal panels cannot be uniform, it is observed that the color is uneven and becomes extremely remarkable. In the fourth embodiment, the phase difference plate 3 5 3 is inserted between the reflective liquid crystal element 351 and the second polarizing plate 3 5 2b in the MTN mode as described above, which is even smaller than the third comparative example. In the case of an oblique optical system, although the left and right contrast inclination may be a little, they are all in the practical range and have the so-called feature that no interference phenomenon caused by reflection on the surface or inside the interface is observed. Next, a fifth embodiment of the present invention will be described. Fifth Embodiment -47- (44) (44) 200400378 is the same optical arrangement as Fig. 24 (A) and (B), but a reflective liquid crystal of SCTN mode is used as the reflective liquid crystal element 3 5 1 The components are different from the fourth embodiment. That is, the liquid crystal molecules of the liquid crystal layer 3 56 are composed of nematic liquid crystal, and the pretilt angle thereof is set to 2 ° to 5 °, and the twist angle of the liquid crystal layer 3 56 is set to approximately 60 °. And the liquid crystal alignment azimuth angle of the transparent substrate 354 side and the reflective substrate 3 55 side is set to any one of about 150 degrees, about 210 degrees, or formed at about 330 degrees and about 30 degrees. Furthermore, the wavelength normalized retardation of the liquid crystal layer 356 is 0.  5 5 or more 0 · 6 5 or less. On the surfaces of the transparent substrate 354 and the reflective substrate 355 that are in contact with the Chang layer 356, an alignment film (not shown) coated with a polyimide resin surface, for example, is formed to impart alignment to the liquid crystal molecules. In the actual system of this fifth embodiment, the visible angle characteristics obtained from the simulation are shown in Fig. 29. When viewed from the azimuth angle of 90 degrees, the black color sinks (the light intensity during black display is extremely small). When viewed from a polar angle of 15 to 20 degrees (viewing the light reflected from oblique incident light), the characteristics can be found to be extremely good. Here, 5 V is applied to each pixel electrode for black display. In the fifth embodiment, when 5 V is applied to each pixel electrode, the light intensity is formed when the azimuth angle is 70 degrees to 110 degrees, and the polar angle is 0 degrees to 25 degrees. Also, it was confirmed that the black level is extremely good in this angle range, and because the light is incident at an oblique angle, extremely high contrast can be obtained even in an oblique optical system. The incident angle of the light incident on the reflective liquid crystal element is about 12 degrees, and F 値 of the projection lens 3 5 7 is 2. 4 (At this time, the lens taking angle is about 12 degrees, making it possible to take in the visible angle, the polar angle is 0 ~ 24 degrees, -48- (45) (45) 200400378, and the azimuth is in the range of 78 ~ 102 degrees The contrast when projected is 1 000: 1, and it has excellent contrast without left and right contrast tilt. No interference caused by reflections on the surface or inside the interface was observed. Furthermore, the alignment direction of the liquid crystal in the SCTN mode is symmetrical with respect to the incident-side polarizing plate (3 5 2a in FIG. 24) or the outgoing-side polarizing plate (3 5 2b in FIG. 24). Therefore, even in the same twisted state, eight configurations can be conceived, but when the twist angle is 60 degrees, it is desirable to set the orientation angle of the liquid crystal alignment on the transparent substrate side and the reflective substrate side to about 150 degrees, about 2 1 Any one of 0 degrees, or formed at about 330 degrees and about 30 degrees. The reason is that the viewing angle can be widened when set as such. In addition, the phase difference plate 3 5 3 is removed, and the other optical configuration is the same as the fourth comparative example of the fifth embodiment. The actual projection screen is 50: 1 at high contrast, but at low The contrast becomes 30: 1. The fourth and fifth embodiments described above can be said to be the same as those shown in Figs. 21 (A) to (E). However, in FIGS. 31 (A) to (E), the retardation plate 1 〇1 represents the aforementioned retardation plate 3 5 3, and the dish-shaped liquid crystal molecules are shown to be gradually inclined molecules in the thickness direction of the film surface in a mode. arrangement. That is, the retardation plate 1 0 1 (353) is formed in which the optical axis is parallel to the paper surface in FIG. 31. Although the optical axis is inclined to the retardation film film surface, the optical axis is made to correspond to the thickness from the film surface. The angle of inclination is formed to gradually change. The polarizing plates 102, 104, 105, and 106 correspond to the aforementioned second polarizing plate 352b. As described above, the phase-49-(46) (46) 200 400 378 phase difference is used for the incident light incident on the retardation plate, and the polarized light has a negative uniaxial anisotropy and is inclined obliquely. The plate 1 0 1 (3 5 3) is made parallel to the transmission axis of the adjacent polarizing plate 1 2 0, 1 0 4 and 10 5 to reduce the black level, increase the contrast, and expand. The angle range that can sufficiently obtain the contrast ratio (contrast coefficient). In addition, the present invention is not limited to the above-mentioned fourth and fifth embodiments. For example, a retardation plate having an optical axis inclined obliquely may be inserted between the first polarizing plate 3 5 2a and the reflective liquid crystal element 351. between. At this time, the optical axis system of the retardation plate is set to be orthogonal to the transmission axis of the adjacent first polarizing plate 352a. Although the incident direction of light is also shown in the embodiment when reflecting from the bottom to the top, that is, the state of incidence from an azimuth angle of 270 degrees and exit from the azimuth angle of 90 degrees, but even if it is illuminated from the 90 degree direction or from other directions Irradiation, as long as the alignment direction of the liquid crystal array and the optical configuration of the retardation plate are provided, the same effect can be obtained. [Effects of the Invention] As described above, according to the present invention, there are various special features as follows: (1) A phase difference plate having uniaxial anisotropy such that the optical axis is inclined obliquely to the film surface is inserted into the pole. Between the reflection means and the reflective liquid crystal element, or between the reflection type liquid crystal element and the analyzer (analysis) means, and the optical axis of the phase difference plate is set to be a polarization means or detection means adjacent to the phase difference plate. The transmission axis of the polarizing means can reduce the black level. Therefore, a projection image (image) with a high contrast ratio (contrast coefficient) can be obtained, and the angle range that can obtain sufficient contrast can be expanded. (2) Without the use of polarized beam splitting (PBS), only polarized P-polarized light (polarized light) can be analyzed by polar -50- (47) (47) 200400378 and polarizing means. Or S-polarized light, it is possible to realize a bright optical system at a lower cost than an optical system with PBS. (3) Since PBS is not used, it is necessary to make incident light incident on the reflective liquid crystal element obliquely. However, since it can be adjusted most appropriately only around the incident angle, a very high contrast ratio can be obtained. (4) Since the conditions for forming a polarizing plate for polarization means are not strict (wide), various polarizing plates can be applied. (5) The polarization method and the polarization detection method are independent and have a Nicol relationship. Therefore, there will be no projection interference stripes on the screen. After color separation, the polarization method and the polarization detection method are provided. Therefore, it does not have the problems of birefringence in the color separation and synthesis system or the reduction of the polarized light purity of the device that performs color synthesis after the polarization detector, and therefore has stability to heat and the like. (6) The phase difference plate and the approaching polarizing means or polarizing means are fixed to be integrated into one body, so that unnecessary surface reflection can be eliminated, and the transmittance can be improved. (7) The retardation plate is configured to be adhered to the back surface on which the antireflection layer is formed, so that unnecessary interface reflection can be reduced, bright projection can be performed, and refraction caused by unevenness on the surface can be suppressed. The resulting image is blurred and distorted. (8) When a reflective liquid crystal element of NW mode is used, S polarized light is used for incident light, and it is inserted at a phase where the optical axis has a negative uniaxial anisotropy and the optical axis is inclined obliquely to the film surface. The difference plate is between the polarization means and the reflective liquid crystal element, or -51-(48) (48) 200400378 between the reflection type liquid crystal element and the analyzer, and the optical axis of the phase difference plate is set to be adjacent to The transmission axis of the polarizing means or the polarizing means of the phase difference plate is orthogonal, so that the black level can be reduced. Therefore, a projection image with a high contrast ratio can be obtained, and the angle at which the contrast can be sufficiently obtained can be widened. range. (9) Since a comparative driving can be performed at a low voltage, the driving transistor can be made small and high resolution can be achieved. (10) Because the voltage dependence of chromaticity is small, driving at a lower voltage becomes feasible and is superior to high-speed response. Therefore, when the display element of the present invention is used, the projection type liquid crystal display device can be smoothly performed. Display of dynamic images. (11) Since the liquid crystal display element of the present invention can be produced using a stable liquid crystal alignment process, the liquid crystal display element and the projection device can be supplied at low cost. [Brief Description of the Drawings] Figures 1 (A) and (B) are block diagrams of the first and second embodiments of the present invention. Figures 2 (A) and (B) are structural diagrams showing a projection device according to the first and second embodiments of the present invention. FIG. 3 is a graph showing a change in transmittance with respect to an angle of a surface including only an axial direction of a retardation plate having an inclined axis shown in FIG. 2. FIG. Fig. 4 is a view showing a viewing angle characteristic of the first embodiment obtained by simulation of the projection device shown in Fig. 2. FIG. 5 is a visible angle characteristic diagram of the second embodiment of the present invention. -52- (49) (49) 200400378 Fig. 6 is a visible angle characteristic diagram of the first comparative example in which a retardation plate having an inclined axial direction is not inserted. Fig. 7 is an explanatory diagram of the visible angle characteristics. 8 (A) and 8 (B) are structural diagrams showing a projection apparatus according to a third embodiment of the present invention. Fig. 9 is a graph showing a change in transmittance with respect to an angle of a surface including only a phase direction of a phase difference plate having an inclined axis according to the third embodiment. Fig. 10 is a view showing a viewing angle characteristic obtained by a simulation of a projection device of the third embodiment. Figure 11 (A) ~ (G) are at Rel / Re2 = 0. 13 ~ 0. Visible angle characteristic map at 8 o'clock. FIG. 12 is a visible angle characteristic diagram of the second comparative example. Figures 13 (A) and (B) are structural diagrams of a fourth embodiment of the projection apparatus of the present invention. 14 (A) to (D) show the relationship between the optical axis of the retardation plate and the liquid crystal alignment direction of the reflective liquid crystal element in the fourth embodiment of the present invention, the detailed structure of the retardation plate, the visible angle characteristics, and the fourth aspect of the present invention. Structural drawing of the embodiment. 15 (A) to (D) show the relationship between the optical axis of the retardation plate and the liquid crystal alignment direction of the reflective liquid crystal element in the fifth embodiment of the present invention, the detailed structure of the retardation plate, the visible angle characteristics, and the fifth aspect of the present invention. Structural drawing of the embodiment. Figs. 16 (A) to (C) show the relationship between the optical axis of the retardation plate of the sixth embodiment of the present invention and the liquid crystal alignment direction of the reflective liquid crystal element, and the visible angle is particularly a structural diagram of the sixth embodiment of the present invention. Figures 17 (A) ~ (C) are optical-53- (50) (50) 200400378 of the retardation plate of the seventh embodiment of the present invention. The relationship between the axis and the liquid crystal alignment direction of the reflective liquid crystal element. A block diagram of a seventh embodiment of the invention. Figs. 18 (A) to (C) are the relationship between the optical axis of the retardation plate of the eighth embodiment of the present invention and the liquid crystal alignment direction of the reflective liquid crystal element, the visible angle characteristics, and the structure diagram of the eighth embodiment of the present invention. Figs. 19 (A) to (C) are diagrams showing the relationship between the optical axis of the retardation plate of the ninth embodiment of the present invention and the liquid crystal alignment direction of the reflective liquid crystal element, the visible angle characteristics, and the structure of the ninth embodiment of the present invention. Fig. 20 is a graph showing the results of the first to ninth embodiments and the first comparative example of the present invention. Figs. 21 (A) to (E) are diagrams showing ideal examples and non-ideal examples among the examples of the retardation plate and the polarizing plate. Fig. 22 is a graph showing the results of the tenth to twenty-ninth embodiments and the second comparative example of the present invention. 23 (A) to (C) are structural diagrams of a third embodiment of the present invention. Figures 24 (A) and (B) are diagrams showing the structure of a projection apparatus according to a fourth embodiment of the present invention. FIGS. 25 (A) to (C) show the relationship between the incident light vibration direction, the optical axis of the retardation plate, and the liquid crystal alignment direction of the reflective liquid crystal element in the fourth embodiment of the present invention. Structure drawing and visible angle characteristics. Fig. 26 is a diagram showing the relationship between the azimuth angle, the polar angle, and the light intensity in the fourth embodiment of the present invention. Fig. 27 is a view showing a visible angle characteristic of the third comparative example. -54- (51) (51) 200400378 Fig. 28 shows the relationship between the azimuth angle, the polar angle, and the light intensity of the third comparative example. Fig. 29 is a view showing a visible angle characteristic of the fifth embodiment of the present invention. Fig. 30 is a diagram showing the relationship between the azimuth angle, the polar angle, and the light intensity in the fifth embodiment of the present invention. Figs. 31 (A) to (E) are diagrams showing ideal rationale and non-ideal examples in each example of a retardation plate and a polarizing plate. FIG. 32 is a block diagram showing an example of a conventional projection device. FIG. 3 is a structural diagram of another example of a conventional projection device. Figures 34 (A) and (B) are structural diagrams of a conventional projection device in which the optical system is colorized. FIG. 35 is a structural diagram of still another example of the conventional projection apparatus. [Description of Symbols] A1: Light source A2: Lens group A3: Color separation optical system A4: Polarization means A5, B1, 53, 63, 73, 81, 86, 91, 95, 101, 111, 3 5 3: Phase Differential plates A6, 51, 61, 71, 351: Reflective liquid crystal element A7: Means of analysis (polar) A8: Color synthetic optics A9, 57, 67, 77, 357: Projection lens -55- (52) (52 200400378 50, 60, 70, 350: The projection devices 52a, 62a, 72a, 352a of this embodiment: the first polarizing plate 52b, 62b, 72b, 352b: the second polarizing plate (polarizer) 54 , 64, 74, 354: Transparent substrate 55, 65, 75, 3 5 5: Reflective electrode (electrode) 5 6, 66, 76, 3 5 6: Liquid crystal layer 1 1 2, 1 1 4: Adhesive layer 1 1 3: Polarizing plate 1 1 5: Glass layer 1 1 6: Surface reflection preventing layer -56-

Claims (1)

(1) (1) 200400378 Patent application scope 1. A projection device using a reflective liquid crystal element is a system that uses three primary colors of light obtained by color separation of light emitted from a light source by color separation means to be transmitted and polarized. Means, and incident on a reflective liquid crystal element formed by sandwiching a liquid crystal layer between a transparent substrate and a reflective substrate, and the aforementioned reflective liquid crystal element is adjusted in accordance with the image data from the reflective liquid crystal element. The incident light is polarized by the polarizing means arranged in a relationship of orthogonal Nicol with the aforementioned polarization means, and the projection lens magnifies and projects the oblique light of the polarizing light by the polarizing means. A reflection type liquid crystal element of a projection optical system is characterized in that it is provided between the polarization means and the reflection type liquid crystal element, or between the reflection type liquid crystal element and the polarization detecting means. An anisotropic retardation plate whose optical axis is inserted obliquely with respect to the film surface, and the optical axis system of the aforementioned retardation plate is set orthogonally to the adjacent The transmission axis of the polarizing means or the polarizing means of the phase difference plate. For example, a projection device using a reflective liquid crystal element in the first patent application range, wherein the reflective liquid crystal element makes the dielectric anisotropy negative. The nematic liquid crystal is made with a pre-tilt angle of 80 degrees to 89 degrees, and the azimuth angle is set to (4 5 + 90χ n) degrees [but n is an integer angle] for the incident light, and the optical axis of the aforementioned retardation plate It is set to be parallel to the vibration plane of the incident P-polarized aurora. 3 · For a projection device using a reflective liquid crystal element as described in item 1 of the patent application range, wherein the aforementioned polarization means is set to pass the characteristics of S-polarized aurora -57- (2) (2) 200400378, and the aforementioned phase difference plate system It is arranged between the polarizing means and the reflective liquid crystal element, and the reflective liquid crystal element makes a pretilt angle of nematic liquid crystal with negative dielectric anisotropy of 80 to 89 degrees, and for The incident light is set to an azimuth angle of (4 5 + 90χ η) [but η is an integer angle], and the optical axis system of the aforementioned retardation plate is set to be parallel to a plane perpendicular to the incident S-polarized polarized light vibration plane. 4. The projection device using a reflective liquid crystal element as described in item 1 of the scope of the patent application, wherein the phase difference plate has dish-shaped liquid crystals as the basic negative uniaxial commonality, and the inclination of the dish-shaped liquid crystals approximately becomes The same, and its pre-tilt angle is 40 degrees ~ 80 degrees. 5. The projection device using a reflective liquid crystal element according to item 1 of the scope of the patent application, wherein the phase difference plate has dish-shaped liquid crystal as a basic negative uniaxial anisotropy. When there is a change in the tilt, the larger one of the dish-shaped liquid crystals is arranged relatively close to the polarizing means or the polarizing means side. 6. For a projection device using a reflective liquid crystal element, such as in the scope of application for patent No. 1, 2, 3, 4 or 5, wherein the aforementioned retardation plate is fixed integrally with the aforementioned polarizing means or the aforementioned polarizing means. 7. For a projection device using a reflective liquid crystal element, such as in the scope of application for patent No. 1, 2, 3, 4 or 5, wherein the aforementioned retardation plate is adhered to the back of the glass plate on which the antireflection layer is formed on the surface. 8. For a projection device using a reflective liquid crystal element as claimed in item 6 of the patent application scope, wherein the retardation plate is adhered to the back of the glass plate on which the antireflection layer is formed on the surface. -58- (3) (3) 200400378 9 · Projection device using a reflective liquid crystal element as described in item 1 of the patent scope, wherein the aforementioned reflective liquid crystal element is a nematic liquid crystal with a pre-tilt angle of 2 degrees ~ 5 degrees, and the twist angle of the liquid crystal layer is 80 ~ 90 degrees, and the orientation angle of the liquid crystal alignment on the transparent substrate side is in the range of 1 90 degrees to 200 degrees or 280 degrees to 290 degrees, and the wavelength of the liquid crystal layer MTN modalities with normalized delays from 0.35 to 0.55. 1 〇 · For a projection device using a reflective liquid crystal element according to item 1 of the scope of patent application, wherein the aforementioned reflective liquid crystal element is a nematic liquid crystal with a pre-tilt angle of 2 to 5 degrees, and the twist angle of the liquid crystal layer It is about 60 degrees' and the liquid crystal alignment azimuth angle of the transparent substrate side and the reflective substrate side is set to use any one of about 150 degrees and about 210 degrees, or any one of 300 degrees and about 30 degrees, and In other words, the wavelength of the liquid crystal layer is standardized to a SCTN mode of 0.55 to 0.65. -59-