TWI292501B - - Google Patents

Description

1292501 (1) 玖 发明 发明 发明 发明 发明 发明 发明 发明 发明 发明 发明 发明 发明 投影 投影 投影 投影 投影 投影 投影 投影 投影 投影 投影 投影 投影 投影 投影 投影 投影 投影 投影 投影 投影 投影 投影 投影 投影 投影 投影 投影 投影 投影 投影 投影 投影 投影 投影 投影A projection device for a reflective liquid crystal element that performs a large image (image) on a panel or the like. [Prior Art] In recent years, there has been considerable progress in the case of reflecting a reflective liquid crystal panel in which a reflective electrode is provided in each pixel to increase the number of apertures, and a projection type liquid crystal projector using the reflective liquid crystal panel is used. Has entered the market. This reflective liquid crystal panel can achieve a high number of apertures compared to the prior art transmission type liquid crystal panel, so that a compact/high-efficiency projection apparatus (projector) can be realized. Fig. 3 is a structural view showing an example of a projection apparatus using a conventional (conventional) reflective liquid crystal element. As shown in the figure, the reflective projection apparatus 10 of the projection apparatus is roughly composed of a light source η, a polarization beam splitter (PBS: Polarization Beam Splitter) 12, a color separation 稜鏡 14, and a reflective liquid crystal panel 16R, 16G, 16B (R). It is red, G is green, B is blue), and is composed of a projection lens 17 and the like. In the above configuration, the light beam emitted (ejected) from the light source 11 is extracted by the polarization separation 稜鏡1 2 while being linearly polarized, and is incident on the color separation 稜鏡 14 by the bending traveling direction of 90°. Further, the light incident on the dichroic prism 14 is separated into red, green, and blue (RGB) primary light beams, and 1292501 (2) in each of the reflective liquid crystal panels corresponding to the primary color light. After 1 6 G, 1 6 B is reflected, 'the second light beam (polarized light) is separated by the same optical path. In this case, in the light in which the respective reflective liquid crystal panels 16R, 16G, and 16B are modulated by the image, the reflected light in the region in which the liquid crystal is in the ON state is rotated, and the polarization (polarized) light direction is rotated. Reflected at 90°, the polarized light separating prism 12 is transmitted and projected from the projection lens 17 toward a shadow screen (not shown) to form an image. In the above-described conventional reflection type projection apparatus 10, since the polarization separation 稜鏡1 2 using expensive optical parts is used, there is a problem that the cost of the reflection type projection apparatus 1 is increased. Further, when polarized light (hereinafter referred to as polarized light or polarized light) is separated from the 稜鏡1 2 to separate the polarized light, the light of the light source 1 1 is broadened (for example, the width of ±12 degrees is widened), and it is difficult to form a good light. The problem of separating the polar light.

In order to solve the problem, the proposal discloses a projection device that uses a reflective liquid crystal element that is formed to be incident in an oblique direction without using a polarized light separation prism (PBS) (Japanese Patent Laid-Open Publication No. 2000- 1 998 83) ). Fig. 3 is a structural view showing a projection apparatus according to the proposal. In the same figure, the front reflective projection device 20 of the projection device, the light emitted from the light source 21 is reflected by the reflector 22 into a slightly parallel light, and is directly incident on the first polarizing plate 23, and After linearly polarized light (S-polarized light or P-polarized light) is formed here, it is incident on a color separation/color synthesis means (separation or dichroic mirror). The color separation/color synthesis means (here, the color separation 稜鏡 24) separates the white light into three primary colors of RGB (3) 1292501 and is incident on the reflective liquid crystal panels 26R, 26G, and 26B. On the other hand, when a vertical alignment type liquid crystal panel is used as the reflective liquid crystal panel 2 6 R, 2 6 G, and 2 6 B, when a voltage is not applied to the reflective liquid crystal panel and liquid crystal molecules are vertically aligned (orientated), The polarization state of the incident light is constant and the state is maintained to be reflected by the reflective liquid crystal panels 26R, 26G, and 26B. At this time, the reflected light passes through the color separation 稜鏡 24, and is absorbed by the second polarizing plate 25 which is disposed in front of the projection lens 27 in the orthogonal polarization relationship with respect to the first polarizing plate 23. It is not projected onto the projection lens 27. That is, the black display will be realized. On the other hand, when a voltage is applied to the reflective liquid crystal panels 26R, 26G, and 26B to form the liquid crystal molecules in a horizontal state, the polarization state of the incident light changes, and the incident light is incident on the reflective liquid crystal panel. 2 6 R, 26G, 26B are reflected. At this time, the reflected light passes through the dichroic mirror 24 again, passes through the second polarizing plate 25, and is projected by the through lens 27. That is, a white display will be achieved. The color separation 稜鏡 24 of the color separation/color synthesis means has a function of allowing the incident light from the light source 21 to be color-separated into three primary colors and causing each to be incident on the reflective liquid crystal panel 2 6 R, 2 6 G, 2 6 B, and There is a work state in which light reflected from the reflective liquid crystal panels 2 6 R, 2 6 G, and 2 6 B is color-synthesized. The principal axis of the incident light must be incident on the reflective surface of the reflective liquid crystal panel 2 6 R, 2 6 G , and 2 6 B in the state of S wave or P wave. That is, when incident in other states, due to the difference in the reflection characteristics of the dichroic prism 24, the reflective liquid crystal panel 2 6 R, 2 6 G, 2 6 B reflects and passes through the color separation. The polarized state of the secondary light will not be linearly polarized to 12125501 * (4) light, so that a good black display cannot be obtained. Also, the alignment of the liquid crystal molecules needs to be formed to form a slightly vertical alignment. In the present projection apparatus, when the light incident on the S wave (P wave) is incident on the vertically aligned reflective liquid crystal panels 26R, 26G, and 26B, the polarization state thereof does not change. That is, the direction of polarization of the incident linearly polarized light is perpendicular or parallel to the optical axis of the liquid crystal which is vertically aligned, so that the polarization state is not disturbed, and the original state is maintained to reach the second polarizing plate 25 And is absorbed by it and realizes black display. Further, as an example of colorization of an optical system, the projection apparatus of Fig. 34 has been known from the past. The same figure (A) is a plan view of the reflection type projection device 30, and Fig. (B) is a side view of the reflection type projection device 30. The reflective projection device 30 of the conventional (preferred) projection device is composed of a light source 21 for generating illumination light, a reflector 22 for causing illumination light to be reflected by parallel light, and a predetermined polarization characteristic for illumination light (for example, aurora). a polarizing plate 31 for use; a color separation orthogonal 稜鏡 32 having different characteristics of reflection characteristics by polarization; and a polarization detecting element 33 for generating a color generating function for light incident on the color separation orthogonal 稜鏡 32 And the reflective display elements 34R, 34G, and 34B disposed in the vicinity of the color separation orthogonal 稜鏡 32 (the light source 21, the reflector 22, the polarizing plate 31, and the polarization detecting element 33 are configured as an illumination system) . Further, the reflection type projection device 30 has a projection lens 36. In the reflection type projection device 30, after the light emitted from the light source 21 is linearly polarized by the polarizing plate 31, the light is separated by color, and the system is combined, and the birefringence generated here is generated in the output. Uniform, and the contrast obtained is also low. Further, in the liquid crystal element of the reflective projection element 34R, 3 4G, 1292501 (5) 3 4 B, the alignment direction of the liquid crystal molecules is required to be substantially vertical, but when an electric field is applied, the tilt direction of the liquid crystal molecules is confused. The generation of the alignment state is discontinuous, so that there is a disadvantage that the noise is revealed when the fine image is mapped. Further, there is a disadvantage that the effect of the interference fringes on the projected image is exhibited by the influence of the color separation cross prism 32 and the reflective display elements 34R, 34G, 34B. In Japanese Patent Laid-Open Publication No. 2001-51-270, it is also proposed to disclose a projection apparatus having a high contrast ratio (contrast coefficient) at a low cost without using an expensive (high-priced) PBS. The projection device 40 shown in Fig. 35. In Fig. 35, the slightly parallel light L1 emitted from the light source 41 is condensed light L2 by the condensing lens 42, and is incident on the display element 45 from the oblique direction by the plate 43 and the multi-layer birefringent element 44. On the display element 45, the incident light modulates the polarization direction in response to the image information and reflects it. As for the reflected light, it passes through the multilayer birefringent element and the polarizing plate 43 again, and transmits the lens 46 to reach a shadow (not shown), and maps the image. In the projection device 40, it is revealed that since the alignment direction of the phase-input axis closest to the birefringent element and the alignment direction of the liquid crystal are combined, it is not necessary to perform birefringence element for birefringence compensation from the oblique direction. Technology. Although the projection apparatus 40 does not specifically disclose a method of producing a color image, it is conceivable that the light of the color separation system is incident on the color synthesis system by means of polarization and light detection (analysis) means. . In this case, it is true that it is different from the aforementioned conventional reflection type projection device 30 and is formed as an optical system which does not have the birefringence effect of the color separation and synthesis system -9- 1292501 (6). However, the prior projection device 40 still has the following problems. Since the means for polarizing or detecting light is the same, the influence from the reflecting surface of the display element 45 cannot be avoided, and the interference pattern is displayed on the projected picture. Further, the multilayer birefringent element 44 is in the wavelength of light of the wide wavelength, and strictly requires a phase difference of λ /4 wavelength to be generated, provided that the characteristics constituting any of the multilayer birefringent elements 44 cause a failure (not according to its characteristics). There is a deviation from this condition, and when the light is amplified by the illumination of the 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 on the illumination surface is improved. Such a problem, especially in the prior projection device 40, can become significant. The conventional device 40' birefringent element (phase difference plate) 44 described in Japanese Laid-Open Patent Publication No. JP-A No. 2001-5-1702 is a plate of λ Μ wavelength, but other than The proposal discloses a projection display device using a birefringent optical material having an inclined optical axis (Japanese Laid-Open Patent Publication No. Hei 9-197397, JP-A-2000-321576). There are also many publications that incorporate phase difference plates in the optical system to improve the viewing angle characteristics and the like. For example, the prior art projection apparatus disclosed in Japanese Laid-Open Patent Publication No. Hei 9-197397 uses a phase difference plate having a tilted axis. The device is not a reflective liquid crystal panel, but a transmissive liquid crystal panel. The transmissive liquid crystal panel having polarizing means and a light detecting means on both sides of a liquid crystal cell is provided with an optical compensation sheet equipped with a phase difference plate. It is between the liquid crystal element and the polarizing means-10-1292501 (7)' or between the liquid crystal element and the light detecting means, or between the liquid crystal element and the polarizing means 'light detecting means. In the conventional device, it is revealed that the contrast when viewed from the front, the upper and lower sides, and the like can be improved without lowering the contrast when viewed from the front. However, the comparison of the conventional devices is extremely low at around 100, and the comparison of the 50,000:1 required by the projector is not discussed. Further, since the liquid crystal panel is of a transmissive type, the liquid crystal element can be transmitted only once, and the characteristic deviation caused by the transmission of the liquid crystal layer twice or the influence of the reflection of the substrate is not considered at all. Japanese Laid-Open Patent Publication No. 2000-321576 discloses a display device in which a reflective phase active plate element using nematic liquid crystals is superposed on a tilted retardation plate. Since a reflective liquid crystal element is used, it is possible to display high-intensity and brightness, and it is possible to display a high-definition image. Therefore, it is superior to the conventional device described in Japanese Laid-Open Patent Publication No. Hei 9-1 97 3 97. However, the light that enters the component passes through the same phase difference plate, so the contrast that can be obtained is less than 1 ,, which is not at all the level that can be used by the projector component. It is also proposed to disclose before the color separation synthesis system. Optical system 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 bulb is separated into RGB by the color separation optical system, and then the polarized light is polarized (polarizer) to be incident on the reflective liquid crystal element, and the reflected light is in the color synthesis system. Before the detection (analyze), it is called to obtain a comparison of -11 - 1292501 (8) 3 0 0~5 00:1. However, in the optical system described in the above-mentioned Document 1, when the vertical alignment-reflective liquid crystal element is used, there is no problem in that the contrast of the intended degree is improved, and there is a problem that the difference is produced by the position of the contrast on the projection screen. There are also proposals for a liquid crystal mode in which a dielectric type which is formed by a liquid crystal which is substantially formed on a substrate when a voltage is not applied is a reflection type liquid crystal which uses a positive nematic liquid crystal. For example, the special publication No. 1 0-9073 1 discloses self-compensating distortion (twisting) to 歹 [J (SCTN: Self-Compensated Twisted)

The modality is disclosed in Japanese Patent Laid-Open No. 2000-2843 No. 1 and No. 2000-298277, or in Document 2 [Japan Display '89, pl92 (1 9 8 9)], which discloses TN-ECB (Twisted Nematic). -Electrically Controlled Birefringence) Modal, commonly known as the MTN (Mixed Twisted Nematic) mode, and in Document 3 [Appl.  Phys· Left.  68, p. 1 45 5 (1 996)] also reveals the MTN mode. These modes are used to display white when no voltage is applied, or when a voltage of a threshold is applied, and a normal (normal) white type of reflective torsion is displayed when a voltage is sufficiently applied. Column liquid crystal display mode (NW mode). However, in these modes, when a sufficient voltage is applied, although the liquid crystal is made vertical and black is displayed, even if a voltage is applied, the liquid crystal molecules are brought close to the horizontal alignment, so that a delay occurs. There is a problem that the so-called black level becomes poor. In order to fully apply the voltage, it is necessary to increase the driving voltage of the active matrix. For this reason, the transistor will become large, which will damage the so-called reflective liquid which can be used as a pixel at a high density. 12-126291 (9) Crystal The advantages of the components. Also added is the problem that the so-called visible angle becomes bad. As explained above, the prior projection devices using the various liquid crystal display elements described above have a length and a length. Further, it has not been proposed to disclose a projection apparatus which can obtain a reflection type liquid crystal display element which is less than 500 Å··1 or more and which hardly causes interference fringes or left and right unevenness, without using PBS. The present invention has been made in view of the above, and an object thereof is to provide a projection apparatus using a high contrast (500:1 or more) reflective liquid crystal element which is required as a projection apparatus. Still another object of the present invention is to provide a projection apparatus which does not use PBS and which uses a reflective liquid crystal element which hardly generates interference fringes or left and right unevenness. Furthermore, another object of the present invention is to provide a projection apparatus using a reflective liquid crystal element which can obtain sufficient contrast from a low driving voltage and has a good visible angle in an MTN mode or an SCTN mode. In order to achieve the above object, the present invention is a projection apparatus that uses a three primary color light transmitting polarizing means obtained by color separating light emitted from a light source by a color separating means, and is incident on a transparent liquid crystal layer. a reflective liquid crystal element formed between the substrate and the reflective substrate, wherein the reflective liquid crystal element is configured to be reflected by the polarizing means in response to the reflected light from the reflective liquid crystal element that is modulated in accordance with image data. A reflective liquid crystal element-13-1292501 (10) of an oblique projection optical system in which a light is detected by a light-detecting means for projecting a light detected by a light-detecting means by a projection lens, and is characterized in that Between the polarizing means and the reflective liquid crystal element, or between the reflective liquid crystal element and the photodetecting means, a uniaxial anisotropy, and an optical axis of the phase difference plate inserted obliquely to the oblique direction of the film surface, and the optical axis of the phase difference plate is set to be orthogonal to the polarizing means adjacent to the phase difference plate or to detect The transmission axis of the light means. In the present invention, a phase difference plate having a uniaxial anisotropy and an optical axis inclined toward an oblique direction of the film surface is interposed between the polarizing means and the reflective liquid crystal element or the reflective liquid crystal element and the photodetecting means, and the phase difference plate is inserted The optical axis is set to be orthogonal to the transmission axis of the polarizing means or the light detecting means adjacent to the phase difference plate, so that it can be reflected by the reflective liquid crystal element, and the black of the reflected light absorbed by the light detecting means can be reduced. Level. Further, it is possible to detect (analyze) a predetermined P-polarized light or S-polarized light by a polarizing means and a light detecting means without using a polarizing beam splitter (PBS). In the above-described reflective liquid crystal device, the neotropic liquid crystal having a negative dielectric polarity has a pretilt angle of 80 to 89 degrees, and the incident polarized light is set to have an azimuth angle of (45 + 90 n) degrees [but η is an integer. Angle], and the optical axis of the phase difference plate is set to be parallel to the vibration plane of the incident pupil light. Further, the polarizing means described above is set so as to pass the characteristics of the S-polarized light, and the phase difference plate is disposed between the polarizing means and the reflective liquid crystal element, and the reflective liquid crystal element is formed to make the dielectric negative to the nematic liquid crystal. The angle of the pretilt angle is approximately 80 to 8 9 degrees, and the incident polarized light is set to an azimuth angle of (45 + 9 〇 η) degrees [but η is an integer angle], as for the optical axis setting of the phase difference plate Parallel to a plane perpendicular to the incident S-polar vibrating surface. -14- (11) 1292501 Further, the phase difference plate described above may be configured to have a disk-like liquid crystal as a basic negative uniaxial anisotropy, and the inclination of the disk-shaped liquid crystal will be substantially the same on the upper and lower sides of the film, and the pretilt thereof The angle is 40 degrees to 80 degrees, and the disc-shaped liquid crystal has a basic negative uniaxial anisotropy. When the inclination of the upper and lower disc-shaped liquid crystals of the film changes, the disc liquid crystal may be inclined to be large. The opposite directions are arranged close to the polarizing means or the light detecting means side. Further, in the present invention, the phase difference plate is configured to be integrally fixed to the polarizing means or the light detecting means which are close to each other, thereby eliminating unnecessary surface reflection, so that the transmittance can be improved. Further, in the present invention, the phase difference plate is formed to adhere to the back surface of the glass plate on which the reflection preventing layer is formed. As a result, redundant interface reflections can be reduced. Further, in another aspect of the present invention, when a reflective liquid crystal element having an NW mode is used, S-polarized light is used for incident light, and a phase difference plate in which an optical axis is inclined toward an oblique direction of the film surface is applied to the polarizing means and the reflective liquid crystal. Between the elements, or between the reflective liquid crystal element and the light detecting means, and the optical axis of the phase difference plate is set parallel to the transmission axis of the polarizing means or the light detecting means adjacent to the phase difference plate, The black level of the reflected light absorbed by the light detecting means can be reduced. Further, sufficient contrast can be obtained by the aforementioned polarizing means and the detecting means without using a polarizing beam splitter (PBS). The NW mode reflective liquid crystal element has a pretilt angle of 2 degrees to 5 degrees for the nematic liquid crystal, a twist angle of the liquid crystal layer of 80 degrees to 90 degrees, and a liquid crystal alignment azimuth angle of 190 degrees on the transparent substrate side. Up to 200 degrees or -15- 1292501 (12) 2 8 0 degrees to 290 degrees, and further, the wavelength normalization delay of the liquid crystal layer is 0. The MTN mode of 35 or more 〇·55 or less. Or the reflective liquid crystal element of the NW mode is such that the neat liquid crystal has a pretilt angle of 2 degrees to 5 degrees. The twist angle of the liquid crystal layer is about 60 degrees, and the liquid crystal alignment direction of the transparent substrate side and the reflective substrate side is set. The angle is any one of about 150 degrees and about 2 1 0 degrees, or any one of about 300 degrees and 30 degrees, and further, the wavelength normalization delay of the liquid crystal layer is 0 · 5 5 or more, 0. S 5 TN mode of 6 5 or less. [Embodiment] Hereinafter, a projection apparatus using a reflection type liquid crystal element according to an embodiment of the present invention will be described with reference to the accompanying drawings. 1(A) is a block diagram showing a first embodiment of a projection apparatus using a reflection type liquid crystal element according to an embodiment of the present invention, and FIG. 1(B) is a view showing a reflection type liquid crystal element according to an embodiment of the present invention. A block diagram of a projection apparatus according to a second embodiment. In FIG. 1(A), the light emitted from the light source A1 is color-separated by the color separation optical system 3A which transmits the lens group A2 and is separated into RGB three primary colors by color, and then transmits the polarization means A4 and The phase difference plate A5 is incident on the reflective liquid crystal element A6 formed between the transparent substrate and the active matrix reflective substrate sandwiching the liquid crystal layer. On the other hand, in the reflective liquid crystal element A 6, the light-receiving means A7, which is placed in the crossed Nicols relationship, is incident on the polarizing means A4 in accordance with the light modulated by the image data. When the liquid crystal layer of the reflective liquid crystal element A6 is driven to be turned on by the display image data, the photodetecting means A7 transmits -16 - (13) 1292501 incident light, and when the liquid crystal layer is not driven, the light is detected. Means A 7 will absorb incident light and will not pass. The light passing through the light detecting means A7 is color-synthesized by the color synthesizing optical system A8, and then projected by the projection lens A9 onto a shadow screen (not shown). Further, it is necessary to provide the polarizing means A4 after the color separation optical system A3, and to provide the photodetecting means A7 before the color synthesizing optical system A8. From the relationship of the design optical system, the main polarization adjustment function can be set before the color separation optical system A3, but after the color separation optical system A3, it is necessary to be equipped with a linear deviation that can degrade the color separation optical system A3. The auroral state becomes a good polarizing means A4. In the oblique projection optical system [off-axis], the phase difference plate A5 disposed between the polarizing means A4 and the reflective liquid crystal element A6 has a uniaxial anisotropy, and the optical axis thereof is inclined toward the film surface. The direction is inclined, and the optical axis is orthogonal to the transmission axis of the polarizing means A4 adjacent to the phase difference plate A5. Thus, a bright optical system can be realized at a low cost without using PB S. Next, the second embodiment of the present invention will be described using the 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 description will be omitted. In the second embodiment, the oblique projection optical system (outside the shaft) is inserted with uniaxial anisotropy, and the optical axis thereof is inclined toward the film surface in the oblique direction, and the optical axis is checked. The transmission axis of the optical means 7 is at the position of the orthogonal phase difference plate B1. Therefore, a bright optical system can be realized at low cost without using PBS. (14) 1292501 (Embodiment) Next, various embodiments related to the present invention will be described. 2(A) and 2(B) show a first embodiment of a projection apparatus using a reflective liquid crystal element according to an embodiment of the present invention, and display black display and white display in the first and second embodiments. The structure of the time. In the projection device 50 of the reflective liquid crystal device according to the first embodiment of the present invention, the projection optical path of the reflective liquid crystal element is arranged to take a straight line from the incident light in FIGS. 2(A) and 2(B). The first polarized light (polar polarized light) plate 52a for polarized light and the phase difference plate 53 having an inclined structure in the axial direction, and the second polarized light is disposed on the reflected light path from the reflective liquid crystal element 51 Plate (light detector) 52b. The reflective liquid crystal element 51 has a transparent substrate 54 and a reflective substrate 55' disposed opposite each other and has a liquid crystal layer 56 interposed therebetween. Further, although not shown, a transparent electrode having a common electrode is formed on the opposite surface of the transparent substrate 54, and a plurality of matrix forms are formed on the opposite surface of the reflective substrate 55 to form each pixel. The MOS transistor, or a driving circuit such as a TFT, and a reflective electrode. As the pixel size, a small pixel such as ΙΟμπίχΙΟμιη is formed. Further, the liquid crystal molecules which are the liquid crystal layer 56 have a negative alignment type negative dielectric anisotropic nematic liquid crystal. In the surface of the transparent substrate 54 and the reflective substrate 55 which are in contact with the liquid crystal layer 56, an alignment film (not shown) formed of a polyimide film, for example, which is subjected to a rubbing treatment, is formed, and for example, liquid crystal molecules in an initial state are given, for example. An angle of inclination of about 80 to 89 degrees and an azimuth angle of about 45 degrees are given to the polarization axis of the polarizing plate. Further, Fig. 2 (Α) is in a state where no electric field is applied to each of the pixel electrodes (initial-18-1292501 (15) state, the display shows a black normal black (NB) mode, and the liquid crystal layer is in an open state. The same figure (B) shows a white mode, which shows the state in which the liquid crystal layer 56 is driven to be turned on. Next, the action related to the present embodiment will be described in Fig. 2 (A), (B), never First, the light emitted from the light source shown in the figure is first taken out by the first polarizing plate 52a, and then modulated by the phase difference plate 53 whose axis direction is inclined, and is incident on the reflective liquid crystal element 51. The optical axis of the slanted phase difference plate 53 is arranged in the plane in which the P-polarized light is oscillated. The phase difference plate 53 having the slanting axis is disclosed, for example, in Japanese Patent Laid-Open No. Hei 9-119397 or The disk-shaped (circular) liquid crystal of the publication No. 2000-321576 is placed on a substrate, etc. The light incident on the reflective liquid crystal element 51 passes through the liquid crystal layer 56 and is reflected by the reflective electrode on the reflective substrate, and further passes through the liquid crystal. The layer 56 and the transparent substrate 54 are emitted and incident on the second polarizing plate. [Detector or Photodetector] 52b ° Here, if the liquid crystal layer 56 is disconnected without applying an electric field to each of the pixel electrodes, the polarized state of the incident light remains unchanged as it is on the reflective substrate 55. It is reflected. At this time, the reflected light is absorbed by the second polarizing plate (photodetector) 52b disposed in front of the projection lens 57, and thus becomes as shown in Fig. 2(A), and is not incident on the light. The projection lens 57. That is, the black display is realized. On the other hand, when an electric field is applied to each of the pixel electrodes to drive the liquid crystal layer 56 to be turned on, the incident light of the reflective liquid crystal element 51 is polarized. It is rotated and reflected on the reflecting plate 55. At this time, the reflected light is formed as shown in Fig. 2(B), and passes through the second polarizing plate (photodetector) 52b and via -19-1292501 (16). The projection lens 57 is enlarged and projected onto a shadow screen (not shown). The pre-tilt angle of the liquid crystal layer 56 is exemplified as an example. As a characteristic of the phase difference plate 53 having an inclined axis, For example, the angle on the substrate side is 4 degrees, and the surface side angle is 80 degrees. Only this has a tilt axis. The change in transmittance measured by the optical system in which the phase difference plate 53 is inserted in the orthogonally polarized state in which the first polarizing plate 52a and the second polarizing plate (lighting mirror) 52b are placed is shown in Fig. 3. The axis shows the transmittance, and the horizontal axis shows the polar angle. As shown in the figure, the transmittance characteristic shows the maximum near the pole angle of -60 degrees and the smallest at around 35 degrees. The actual system system using the phase difference plate 5 3 The visible angle characteristic obtained by the simulation is as shown in Fig. 4. At the azimuth angle of 90 degrees, it can be seen that the black level near the pole angle of 15 to 20 degrees becomes small. [Fig. 4, the dotted line The circle is a 20 degree unit with a polar angle, and the circle with the smallest diameter shows a pole angle of 20 degrees: (the visible angle characteristic map below is also shown in the same). Let the angle of the light incident on the liquid crystal layer 56 be about 12 degrees, and the F 値 of the projection lens be 2 · 4 (the angle of the lens taken in this state is about 12 degrees, and thus, in the visible angle, Can be taken into the polar angle 0 to 24 degrees, the azimuth angle of 2 5 8~2 7 2 degrees of light) to project on the screen, the contrast is about 6 5 0 : 1 and there is no left and right contrast tilt (left and right uneven ), and can form a uniform display. No interference phenomena accompanying the inside of the surface or (interface) interface were observed. Next, a second embodiment of the present invention will be described. The structure of the present embodiment is the same as that of the first embodiment shown in Fig. 2. However, as the phase difference plate 53 having the tilt axis, for example, the angle of the substrate side is 1 〇, and the angle of the surface side is -20 - 1292501. (17) Where the degree is 70 degrees, there are differences. The visible angle characteristic of this embodiment is as shown in Fig. 5, and the visible angle of the azimuth direction of the black level near the angle of 10 degrees in the azimuth angle of 90 degrees can be observed. And when the projection is on the screen, the contrast is about 600:1, and there is no contrast between the left and right sides to become uniform, and no interference phenomenon caused by the reflection inside the surface or the (interface) interface is observed. When the phase difference plate 53 which is inclined in the axial direction is not inserted, the first comparative example will be described, and the difference between the first comparative example and the second embodiment will be described. Further, the structure of the first comparative example is the same as that of Fig. 2 except that the phase difference plate 53 is not provided. In the first comparative example, the tilt phenomenon of the black level in the left-right direction can be seen on the surface of the actual projection. The contrast is 700:1, but the contrast is 300:1. Interference phenomena accompanying surface or internal reflections of the interface were also observed. The visible angle characteristics of this first comparative example will be shown in Fig. 6. The visible angle characteristic of Fig. 6 shows that when the black display of the liquid crystal is not applied, if the pretilt angle (degree) of the liquid crystal is present, the position at which the contrast can be obtained lies in the center portion, although it is in the polarization direction and orthogonal. The contrast in the direction of the polarization direction is high, but especially from the incident angle of the oblique direction light of 45 degrees in the polarization direction, the light leaks rapidly, so that the black level is raised and the contrast is lowered. When viewing from the portion where the azimuth angle of light incidence is 90° (corresponding to the state of light incident from the obliquely oblique direction and reflected from the obliquely upward direction), it can be observed that the polar angle becomes small (when incident light is obliquely), The black level that can be obtained corresponding to the azimuthal position has a change. This means that on the projected picture, there is a black level tilt in the left-right direction, so that there is a contrasting tilt on the left and right sides -21 - (18) 1292501. This phenomenon is observed in the case of color synthesis, and the characteristics of the reflective liquid crystal panel are inconsistent due to inconsistencies in color, and are extremely remarkable. Furthermore, Figure 7 shows the focus of the visible angle characteristics. As shown in the figure, usually (on-axis: on axis) is perpendicular to incident light and is emitted vertically, so the characteristics of the central portion of the circle are extremely important, but when it is off-axis, the light is incident obliquely, so that the portion Features become important. Generally, the incident light is supposed to be parallel light, but in any case it is irradiated with concentrated light so that the light is irradiated in a (reverse) conical shape. The angle of enlargement of the cone is referred to as the cone angle, and the range characteristics of the light of the angle become of importance. For example, when the cone angle is 15 degrees and the outside of the axis is outside, the center of the light is at a pole angle of 0 degrees (just at the center). Therefore, if the cone angle is included, the pole angle is 15 degrees (radius 15). It will become an important part of the circle. Considering, for example, the state of incident light at a polar angle of 16 degrees (16 degrees from vertical) from the azimuth angle of 270°, the reflected light will be centered at 90 degrees azimuth and 16 degrees from the polar angle. The range within the ellipse shown. From this point of view, it can be seen that in the present embodiment, the black portion of the portion is good. As described above, according to the second embodiment described above, since the optical system is bright without using the PBS, an inexpensive optical system can be realized, and although it is necessary to obliquely incident light to the element, it can be adjusted only around the incident angle. The most appropriate situation allows for extremely high contrast. Further, according to the second embodiment, the polarizing plate conditions are not critical, and the polarizing means (first polarizing plate 52a) and the light detecting means (second polarized light) resulting from reflection from the surface or the interface of the reflective liquid crystal element The board 52b) has an independent orthogonal polarization relationship, and therefore, -22- 1292501 (19) does not form a projection interference fringe on the screen. Further, after the color separation, there is a polarizing means and a light detecting means, and color synthesis is performed after the light detection. Therefore, there is no problem of reducing the purity of the polarized light by the birefringence in color separation and color synthesis, so that Heat is a stable feature. However, in the first and second embodiments described above, the phase difference plate 53 having the uniaxial anisotropy which is inclined obliquely is parallel to the incident P-polar vibration surface, so that the retardation plate 53 is delayed ( The range of the product of the refractive index difference and the film thickness becomes narrow, and the visible angle characteristic which can be obtained becomes narrow. Therefore, in the third embodiment to be described below, the incident polarized light is used as the S-polarized light, and the phase difference plate having the uniaxial anisotropy inclined in the oblique direction is formed to be positive with the incident S-polar vibrating surface. The intersection faces form a parallel. Hereinafter, a third embodiment of the present invention will be described with reference to Fig. 8 . Figs. 8(A) and 8(B) are views showing the configuration of a third embodiment of a projection apparatus for a reflective liquid crystal device according to an embodiment of the present invention in black display and white display. 8(A) and (B), a projection device 60 using a reflection type liquid crystal element according to a third embodiment of the present invention is disposed on the incident light path of the reflective liquid crystal element 61, and is disposed from the incident light. The first polarizing plate 62a having a linearly polarized light and the phase difference plate 63 having a structure in which the axial direction is inclined is further provided with a second polarizing plate (light detecting mirror) on the optical path of the reflected light from the reflective liquid crystal element 61. 62b. The reflective liquid crystal element 61 has a structure in which a transparent substrate 64 and a reflective substrate 6 5 ' are disposed opposite each other with a thin layer ό 6 interposed therebetween. Further, although not shown, a transparent electrode having a common electrode is formed on the opposite surface of the transparent substrate 64, and a pattern formed on the opposite surface of the reflective plate 65 is formed in -23 - 1292501 (20). The MO S transistor, or a driving circuit such as a TFT, and the reflective electrode have a plurality of matrix shapes. As the pixel size, a small pixel such as ΙΟμιηχΙΟμιη is formed in a square shape. Further, as the liquid crystal molecules constituting the liquid crystal layer 66, a negative dielectric anisotropic nematic liquid crystal having a vertical alignment type is used. In order to contact the surface of the transparent substrate 64 and the reflective substrate 65 of the liquid crystal layer 66, an alignment film (not shown) formed of ruthenium oxide, for example, by vapor phase deposition, is formed in order to impart alignment to the liquid crystal molecules, and For example, a tilt angle of about 80 to 89 degrees and azimuth angle of about 45 degrees with respect to the polarization axis of the polarizing plate are given. Fig. 8 (Α) shows a normal black (ΝΒ) mode in which black is displayed in a state where an electric field is not applied to each of the pixel electrodes. Fig. 8(B) shows a mode in which white is displayed. Next, the operation of the third embodiment will be explained. In Fig. 8 (Α), (Β), light emitted from a light source (not shown) is first separated into RGB three primary colors by a color separation optical system (not shown), and then taken out by the first polarizing plate 62a. The S-polarized light is then modulated by the phase difference plate 63 which is inclined in the axial direction, and is incident on the reflective liquid crystal element 61. The optical axis of the phase difference plate 63 whose axis direction is inclined is arranged in the plane in which the incident S-polar light is vibrated. The phase difference plate 63 having the slanting axis is used, for example, in the arrangement of the disc-shaped liquid crystal on the substrate, which is disclosed in Japanese Laid-Open Patent Publication No. Hei 9-1 97397 or JP-A No. 2000-32 1576. The ideal form of the phase difference plate 63 is as follows. (1) The phase difference plate 63 is formed of an optically anisotropic layer formed of a transparent substrate (transparent support) and a compound having a dish-like structural unit disposed on the substrate. (2) The disc surface of the disc-shaped structural unit of the optically opposite layer is inclined to the surface of the -242-1292501 (21) transparent support, and the angle formed by the disc surface of the disc-shaped structural unit and the transparent support surface, Will change in the optically opposite layer. (3) The total 所有Rel of all delays 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 equation 3 can satisfy the relationship of the following formula (formula): 4xRe2^ Rel ^ 1. 0xRe2 Φ [However, the delay of the above optical compensation sheet is defined by the following equation: {nl-(n2+n3) /2}xd 2 (in the above formula, nl, n2 and n3 represent the three axes of the optical compensation sheet described above) The refractive index in the direction, each having a small refractive index in this order, d is the thickness in terms of nm of the optical compensation sheet, and the retardation of the liquid crystal layer is defined by the following formula, { m3 (m 1+m2) /2 } xd' 3 (In the above formula, ml, m2 and m3 represent the refractive index in the triaxial direction of the liquid crystal, and each has a small refractive index in each order, and d ' indicates the thickness in nm of the liquid crystal layer)] . Returning to FIG. 8 again, the light incident on the reflective liquid crystal element 61 is reflected by the reflective electrode on the reflective substrate 65 through the liquid crystal layer 66, and is further emitted through the liquid crystal layer 66 and the transparent substrate 64, and It is incident on the second polarizing plate (light detector) 62b. -25- 1292501 (22) When the liquid crystal layer 66 is disconnected without applying an electric field to each of the pixel electrodes, the polarization of the incident light remains unchanged and is reflected on the reflective substrate 65 in the original state. Since the light reflected at this time is absorbed by the second polarizing plate (photodetector) 62b disposed on the front side of the projection lens 67, it is not incident on the projection lens 6 as shown in FIG. 8(A). 7. That is to achieve a black display. On the other hand, when an electric field is applied to each of the pixel electrodes to drive the liquid crystal layer 66 to be turned 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 (photodetector) 6 2 b and is enlarged and projected onto the screen (not shown) via the projection lens 67. . The case where the inclination angle of the liquid crystal layer 66 is 85 degrees will be described as an example. As the characteristic having the tilt axis phase difference plate 63, the substrate side angle was 4 degrees, the surface side angle was 80 degrees, and the film surface direction retardation was about 107 nm. The change in transmittance for the plane angle including only the axial direction of the phase difference plate having the tilt axis is shown in Fig. 9. In the same figure, the vertical axis shows the transmittance and the horizontal axis shows the polar angle. As shown in the figure, the polar angle is around -55 degrees and has the characteristic of showing the highest transmittance. The S-polarized light system is incident from the substrate side. In the actual system system using the phase difference plate 63, the visible angle characteristics obtained by the simulation are as shown in FIG. 10, and it can be seen that the black level near the azimuth angle of 90° and the polar angle of 15 to 20 degrees becomes small. . The angle of incidence of light to 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 the light can be taken at a visible angle, the polar angle is 0 to 24 degrees, and the azimuth is in the range of 78 to 102 degrees) to be projected on the screen. The contrast is 1000:1, and it does not have the left and right contrast tilt, but can be evenly displayed as -26- 1292501 (23). No interference caused by reflections on the surface or inside the interface was observed. Furthermore, the vertical direction of the liquid crystal tilt direction having a negative electrical boundary isotropic liquid crystal, when the incident polarized light is set to an azimuth angle (45 + 90xn) [but η is an integer angle], the voltage is applied to the liquid crystal The brightness is the brightest. However, when set to 45 degrees and 135 degrees, when set to 45 degrees and 225 degrees, or 45 degrees and 3 15 degrees, the black level will be lowered, so it is more desirable. The retardation of the above optical compensation sheet is defined by the above 2, and the retardation Re 1 is 107 nm. The retardation of the above liquid crystal layer is defined by the above formula 3, and at this time, Re2 is 267 nm. Rel is 0 for Re2. 40 times. In Figure 11 (A) ~ (G), it will show Rel / Re2 = 0. 13~0. At 8 o'clock, the angle characteristic map, if the hour is small, has no effect, but the temple will become poor because of the opposite, so the ideal is 0. 2~0. The scope of 5. When the pretilt angle of Chengchang 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 most suitable 値 of the retardation Rel of the phase difference plate having a negative optical uniaxial anisotropy is 86 nm. The incident light is P-polarized light. In the third embodiment, when the phase difference plate 63 whose axis direction is inclined is not inserted, the second comparative example is shown. The other optical configurations are the same as those of the third embodiment and the first comparative example described above. In the actual projection screen, the tilt of the black level in the left and right direction is observed. In the case where the contrast is high, it is 7 0 0 : 1, but in the lower case, it is 3 0 0 : 1. However, interference caused by reflections on the surface or inside the interface was not observed. The visible angle characteristic of this second comparative example will be shown in Fig. 12. From the visible angle characteristics shown in Fig. 1 2 -27- 1292501 (24), it can be seen that when the voltage is not applied to the black display of the liquid crystal, if the tilt angle of the liquid crystal is obtained, the position at which the contrast can be obtained lies in the center portion, although There is a high contrast between the direction of polarization and the direction orthogonal to it, but for the direction of polarization, especially at an angle of incidence from an oblique angle of 45 degrees, the light is quickly leaked to increase the black level and reduce contrast. Also, when the azimuth angle is 90 degrees (corresponding to the incident from the oblique lower azimuth angle of 270 degrees), if the polar angle becomes small (when the light is incident obliquely), it can be seen that the change corresponding to the azimuth angle changes. Black level. This condition means that there is a black level tilt in the left-right direction on the projected screen. This phenomenon is caused by the fact that the characteristics of the three reflective liquid crystal panels do not coincide when the color is synthesized, so that the color unevenness is observed and is extremely remarkable. On the other hand, in the third embodiment, S-polarized light is used as incident light, and optically has a negative uniaxial anisotropy, and the phase difference plate 63 which is inclined obliquely is orthogonal to the incident S. The faces of the vibrating sides of the aurora become parallel, and as shown by the visible angular characteristics in Fig. 10, the black level is lowered, and the contrast is increased, so that the angle range in which the contrast can be obtained can be expanded. Next, a fourth embodiment of the present invention will be described with reference to FIG. Figs. 13(A) and (B) are views showing the configuration of a fourth embodiment of the second embodiment of the projection apparatus according to the embodiment of the present invention in the case of black display and white display. 13(A) and (B), a projection device 70 using a reflective liquid crystal element according to a fourth embodiment of the present invention is provided with a polarizing plate 72a for taking out linearly polarized light from incident light, and is incident on the reflective liquid crystal element 7. In the incident light path of the first light, a phase difference plate 73 having a tilted structure in the axial direction and a second polarized light -28-1292501 ' (25) are disposed on the reflected light path from the reflective liquid crystal element 71. Plate (light-receiving mirror 72b. The reflective liquid crystal element 71 has a transparent substrate 74 and a reflective substrate 75 disposed opposite each other, and has a liquid crystal layer 76 interposed therebetween. Further, although not illustrated, it is transparent. A transparent electrode having a common electrode is formed on the opposite surface of the substrate 74, and a MOS transistor formed for each pixel or a driving circuit such as a TFT is formed on the opposite surface of the reflective substrate 75, and the reflective electrode is made plural. As a pixel size, a small pixel of, for example, about ΙΟμιηχΙΟμιη square is formed. As a liquid crystal molecule constituting the liquid crystal layer 76, a negative alignment dielectric having a vertical alignment type is used, and in contact with The surface of the transparent substrate 74 and the reflective substrate 75 of the crystal layer 76 is formed with an alignment film (not shown) formed of a ruthenium oxide, for example, in a vapor phase deposition direction, in order to impart alignment to the liquid crystal molecules, and is in an initial state. The liquid crystal molecules impart, for example, an inclination angle of about 80 to 89 degrees and an azimuth angle of about 45 degrees with respect to the polarization axis of the polarizing plate. Fig. 13 (Α) shows a state in which an electric field is not applied to each of the pixel electrodes (initial state) The normal black (ΝΒ) mode will be displayed. Figure 13 (Β) shows the white mode. Secondly, the fourth embodiment will be explained. Figure 13 (A), (Β), never shown The light emitted from the light source is first separated into three primary color lights of RGB by a color separation optical system (not shown), and then only the P polarized light is taken out by the first polarizing plate 72a, and is incident on 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 the transparent substrate 74, and is then inclined by the axial direction. The difference plate 73 is modulated. In order to tilt the optical axis of the oblique phase difference plate 73, the optical axis of the inclined phase difference plate 73 will be arranged in the plane in which the incident P-polar light will vibrate. The phase difference plate 73 having the tilt axis will be used, for example, in the country of Japan. The disc-shaped liquid crystal disclosed in Japanese Laid-Open Patent Publication No. Hei 9-197397 or JP-A-2000-32 1576 is placed on a substrate. P-polarized light passing through the retardation plate 73 is incident on the second polarizing plate (detector) 72b. If, at this time, no electric field is applied to each of the pixel electrodes and the liquid crystal layer 76 is open, the state in which the polarization state of the incident light remains unchanged is reflected by the reflective plate 75. At this time, the reflected light Since it is absorbed by the second polarizing plate (photodetector) 72b provided before the projection lens 77, it is formed so as not to be incident on the projection lens 77 as shown in Fig. 13(A). That is, black display is achieved. On the other hand, when an electric field is applied to each of the pixel electrodes to cause the liquid crystal layer 76 to be turned on, the polarization state of the incident light of the reflective liquid crystal element 71 is rotated and reflected by the reflective plate 75. At this time, the reflected light is enlarged and projected onto the shadow screen (not shown) by the second polarizing plate (photodetector) 72b and by the projection lens 77 as shown in Fig. 13(B). A state in which the liquid crystal layer 76 has a pretilt angle of 85 degrees will be described as an example. As the characteristics of the phase difference plate 73 having the tilt axis, for example, the substrate side angle is 4 degrees, the surface side angle is 80 degrees, the film surface direction retardation is about 142 nm, and the azimuth angle is 270 degrees. On the other hand, the light incident on the phase difference plate 73 is incident from the side where the inclination angle is large. Fig. 14 (A) shows the relationship between the optical axis I of the phase difference plate 73 of the fourth embodiment of the present invention and the liquid crystal alignment direction 反射 of the reflective liquid crystal element 71, as shown in the same figure (D). The relationship between the structure of the fourth embodiment and the incident light vibration direction -30-(27) 1292501 and the liquid crystal alignment direction are shown in the cross-sectional direction of the reflective liquid crystal element 71 and the phase difference plate 73, and the like, and the same figure (B) The detailed structure of the phase difference plate 73 in the same figure (D) is shown. In Fig. 14(D), the light incident on the first polarizing plate 72a picks up the P-polarized light that is vibrated in the vibrating surface parallel to the plane of the paper, and enters the liquid crystal alignment direction (the liquid crystal azimuth angle is 45 degrees). Reflective liquid crystal element 71. The light reflected by the reflective liquid crystal element 71 is incident on the phase difference plate 73. The phase difference plate 73 is shown in an enlarged view in FIG. 14(B). When the disk-shaped liquid crystal molecules are composed of disc-shaped liquid crystal molecules, the liquid crystal molecules are arranged as shown in FIG. Point the arrow as indicated by 77. The polarized light of the transmission phase difference plate 73 is transmitted by the second polarizing plate 72b to the S-polarized light that vibrates in the direction perpendicular to the plane of the paper. In the actual system using the phase difference plate 73, the visible angle characteristics obtained by the simulation are as shown in Fig. 14C, and it can be seen that the black level near the azimuth angle of 90 degrees is 15 to 20 degrees. small. The incident angle of the light incident on the liquid crystal layer 76 is about 12 degrees, and the projection lens is F値2. 4 (At this time, the lens take-up angle is about 12 degrees, so it will take the light at the visible angle of the angle 〇~24 degrees, the azimuth angle of 78~102 degrees) to contrast when projected on the screen. 1000:1 and can display a uniform display without contrasting left and right. 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 Fig. 15. Fig. 15 (D) is a view showing the configuration of a main part of a fifth embodiment of a projection apparatus using a reflection type liquid crystal element according to an embodiment of the present invention. In the same figure, the same components as those in Fig. 13 and Fig. 14 (D) will be denoted by the same reference numerals and will not be described. In the embodiment shown in Fig. 15 (D), when compared with the fourth embodiment -31 - (28) 1292501, the phase difference plate 81 which is inclined by the axis is disposed at a reflection type liquid crystal from the liquid crystal azimuth angle of 45 degrees. The reflected light of the element 71 is the same as the optical path of the second polarizing plate 72b. However, the optical axis of the phase difference plate 8 1 is shown by I in Fig. 15 (A), and is configured as shown by 82 in Fig. (B), where the optical axis is from the surface side toward the substrate side, and as a dish. The arrangement of the discotic liquid crystal molecules 8 3 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. Further, as the characteristics of the phase difference plate 81 having the tilt axis, for example, the light exit side angle is 80, the light incident side angle is 4 degrees, and the film surface direction retardation is about 107 nm. In the present embodiment, the light incident on the phase difference plate 81 is incident from the side which is inclined to be small. In the actual system system using the phase difference plate 81, the visible angle characteristics obtained by the simulation are as shown in Fig. 15(C), and the comparison can be seen in the vicinity of the azimuth angle of 90 degrees and the angle of 15 to 2 0 degrees. By the time there is a certain increase, the contrast projected on the screen is about 650: 1, and no left and right unevenness or interference fringes are seen. Next, a sixth embodiment of the present invention will be described with reference to Fig. 16. Fig. 16 (C) is a view showing the configuration of a main part of a sixth embodiment of a projection apparatus using a reflection type liquid crystal element according to an embodiment of the present invention. The same components as those in Figs. 8(A) and (B) are denoted by the same reference numerals, and the description thereof will be omitted. The sixth embodiment shown in Fig. 16(C) is characterized in that it is disposed on the first polarizing plate 62a of the third embodiment to the reflection type liquid crystal element 61 in the embodiment of the second embodiment. A phase difference plate 63 is disposed on the phase difference plate 63 of the incident optical path of the reflective liquid crystal element 61, and a reflective liquid crystal element from the reflective liquid crystal element 61 to the second polarizing plate 62b is disposed at -32-292921 (29 ) 61 where the reflected light path is. The structure other than the phase difference plate 86 is the same as that of the third embodiment. In other words, as shown in FIG. 16(C), the first polarizing plate 62a extracts only the S-polarized light whose vibration direction is perpendicular to the paper surface direction, and the second Aurora plate 62b is as shown in FIG. 16(C). Let the direction of vibration be P-polarized light parallel to the direction of the paper. The liquid crystal alignment direction of the reflective liquid crystal element 6 1 is 225 degrees as shown by VI in Fig. 16 (A), and the optical axis of the phase difference plate 86 is shown by I in the same figure (A). As for the phase difference plate 8 6 whose axis is inclined, the optical axis is as shown in FIG. 16 (C), and is from the surface side toward the substrate side direction, and as its characteristic, for example, the light exit side angle is 4 The degree of light incident side is 80 degrees, and the retardation in the film surface direction is about l〇7 nm. In the actual system system using the phase difference plate 86, the visible angle characteristic obtained by the simulation is as shown in Fig. 16 (B), and the angle of the azimuth angle of 90 degrees is not seen at all. The contrast is nearby, and the contrast when projected on the screen is about 20:1. However, the left and right unevenness or the interference fringes are not seen. Next, the seventh embodiment of the present invention will be described with reference to Fig. 17. Fig. 17 (C) is a view showing a configuration of a main part of a seventh embodiment of a projection apparatus using a reflection type liquid crystal element according to an embodiment of the present invention. In the same figure (C), the same components as those in Fig. 16 (C) will be denoted by the same reference numerals and their description will be omitted. In the seventh embodiment shown in Fig. 17 (C), when compared with the sixth embodiment, the phase difference plate 91 which is inclined with respect to the arrangement axis is used for the reflection type liquid crystal element 61 from the liquid crystal azimuth angle of 225 degrees. The reflected light is the same on the optical path of the second polarizing plate 62b, but is arranged in the optical axis of the phase difference plate 91 of the phase difference plate of -33-(30) 1292501 shown by V in Fig. 17(A). The manner of the discotic liquid crystal molecules such as the discotic liquid crystal is different from that of the sixth embodiment. Here, the phase difference plate 9 1 whose axis is inclined is such that the optical axis is as shown by 92 in FIG. 17 (C), from the surface side toward the substrate side direction, and as its characteristics, for example, the light exit side angle is used. 4 degrees, the light incident side angle is 80 degrees, and the film surface direction retardation 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. There is a difference in the azimuth angle of the phase difference plate 91 of 90 degrees. In the actual system system using the phase difference plate 91, the visible angle characteristics obtained by the simulation are as shown in Fig. 17(B), and the comparison in the vicinity of the azimuth angle of 90 degrees is 15 to 20 degrees. Although there is no improvement, the contrast when projected on the screen is about 5:1, but the left and right unevenness or interference fringes are not seen. Next, the eighth embodiment of the present invention will be described with reference to FIG. . Fig. 18 (C) is a view showing a configuration of a main part of an eighth embodiment of a projection apparatus using a reflection type liquid crystal element according to an embodiment of the present invention. In the same figure (C), the same components as those in Fig. 14 (D) will be denoted by the same reference numerals and their description will be omitted. The eighth embodiment shown in Fig. 18(C) is characterized in that a phase difference plate 95 is provided instead of the phase difference plate 73 of the fourth embodiment shown in Fig. 14 of the second embodiment. Where. The retardation plate 95 is such that the optical axis is as shown in FIG. 18(C), 96, from the front side (light incident side) toward the substrate side (light exit side), and as its characteristic, for example, the substrate side angle is 80. Degree, the surface side angle is 4 degrees, the film surface direction retardation is about 107 nm 'the light phase incident on the phase difference plate 9.5 is different from the phase difference plate 7 3 -34 - 1292501 (31) different' Instead, it is incident from one side of the tilt angle. Fig. 18(A) shows the relationship between the optical axis I of the phase difference plate 95 and the liquid crystal alignment direction 反射 of the reflective liquid crystal element 71. In the actual system system using the phase difference plate 95, the visible angle characteristic obtained by the simulation is as shown in Fig. 18 (B), and an improvement contrast can be seen in the vicinity of the azimuth angle of 90 degrees and the angle of 15 to 20 degrees. 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. Fig. 19 (C) is a view showing the configuration of a main part of a ninth embodiment of a projection apparatus using a reflective liquid crystal element according to an embodiment of the present invention. In the same figure, the same components as those in Fig. 18 (C) will be denoted by the same reference numerals, and the description thereof will be omitted. The ninth embodiment shown in Fig. 19(C) is related to the second embodiment. In comparison with the eighth embodiment shown in Fig. 18 of the embodiment, it is characterized in that instead of the reflective liquid crystal element 171 used in the eighth embodiment, the reflective liquid crystal element 61 is used. The other structure is the same as that of the eighth embodiment. Fig. 1 (A) shows the relationship between the optical axis I of the connector 95 of the ninth embodiment and the liquid crystal alignment direction VI of the reflective liquid crystal element 61. In the actual system system using the phase difference plate 95, the visible angle characteristic obtained by the simulation is as shown in Fig. 19 (B), and it can be seen that there is an improvement in the azimuth angle of 90 degrees near the pole angle of 15 to 20 degrees. In contrast, the contrast when projected on the screen is about 600:1 as in the eighth embodiment, and the left and right unevenness or interference fringes are not seen. The first to ninth embodiments are compared with the first one. The characteristics of the example and the performance obtained by -35- (32) 1292501 are grouped together and shown in Figure 20. In the same figure, CR The contrast ratio (Contrast Ratio), that is, the ratio of the whiteness indicating the difference between the white color and the black color. When the angle of the polarizing plate is such that the incident plane of the reflective liquid crystal element is the plane of the X-axis and the Y-axis, And when the X-axis in the horizontal direction is used as a reference to rotate in a counterclockwise direction as a positive angle, and the incident light is linearly polarized, 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 light is incident from the azimuth angle of 270 degrees (from obliquely downward), the light will vibrate in parallel with the incident surface, so that the angle formed by the X-axis, that is, the angle of the polarized surface will become Fig. 2 is an example of a phase difference plate, a polarizing plate, and incident light in which the axis is inclined. In Figs. 21(A) to (E), the phase difference plate 101 displays the first to ninth embodiments described above. In any one of the phase difference plates 53, 63, 73, 81, 86, 91, 95, the molecular arrangement is such that the discotic liquid crystal molecules are gradually inclined in the thickness direction of the film surface. Poor board 1 〇1 (5 3,6 3,7 3,8 1,8 6,91,9 5) The optical axis is parallel to the paper surface in Fig. 1, and is inclined to the optical axis of the film surface, and corresponds to the thickness from the film surface, so that the tilt angle of the optical axis becomes Further, the polarizing plates 102, 104, 105, 106 correspond to the first polarizing plate 62a or the second polarizing plates 62b, 72b. Fig. 2 1 (A) shows that the display has a transmissive S-polar light. The characteristic polarizing plate 102 is on the light incident side or the light exiting side of the phase difference plate 110, and the light does not form a dished liquid crystal molecule which can completely traverse the phase difference plate 1 〇1. The angle to the incident example. The first example is an example in which the optimum contrast -36-(33) 1292501 ratio (contrast factor) can be obtained, which corresponds to the third embodiment and the fourth embodiment described above. Further, the phase difference plate optical axis is parallel to the paper surface, and the transmission axis of the polarizing plate 102 having only the S-polarized light is perpendicular to the paper surface, and the two are orthogonal to each other (vertically intersecting). 21(B) shows a polarizing plate 104 having a transmissive S-polar light characteristic disposed on a light incident side or a light exit side of the phase difference plate 110, and the light is formed as shown in FIG. An example in which the liquid crystal molecules of the retardation plate 1 〇 1 are incident at an angle. However, in this example, the arrangement of the polarizing plate 104 on the phase difference plate 1 〇1 is substantially parallel to the surface, and is different from the first example shown in FIG. 21(A). The second example is an example in which an ideal contrast ratio can be obtained, and corresponds to the fifth, eighth, and ninth embodiments described above. Further, Fig. 21(C) shows that the polarizing plate 1 〇 5 having the P-polarizing light transmitting property is disposed on the light incident side or the light exiting side of the phase difference plate 110, and the light is formed as shown by 1300. The third example is a non-ideal example in which a sufficient contrast ratio cannot be obtained by incident across the angle of the liquid crystal molecules of the phase difference plate 110, and corresponds to the sixth embodiment described above. In addition, FIG. 21(D) shows that the polarizing plate 106 having the S-polarized light or the P-polarized light characteristic is disposed on the light incident side or the light exiting side of the phase difference plate 101, and the light is formed as shown by 107. An example in which the incident is not possible across the angle of the liquid crystal molecules of the phase difference plate 101. This fourth example is the least desirable example of the most incompatible contrast ratio, and corresponds to the seventh embodiment described above. 2 1 (E) shows that the polarizing plate 105 having the P-polarizing light-transmitting property is disposed on the light incident side of the phase difference plate 101, and the light is formed as shown in 103 to form -37-(34) 1292501 to complete An example of incidence across the angle of the liquid crystal molecules of the phase difference plate 101. The 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 described above, in the third, fourth, fifth, eighth, and ninth embodiments described above, S-polarized light is used for the incident light of the phase difference plate, and the uniaxial anisotropy is negative in optical properties. The phase difference plate 10 1 (63, 73, 81, 95) which is inclined obliquely is formed to be parallel to the surface orthogonal to the direction of the incident polarization of the polarized light, thereby reducing the black level and enhancing Contrast makes it possible to expand the range of angles at which the contrast ratio can be sufficiently obtained. On the other hand, in the above embodiments, only the phase difference plate structure having the tilt axis is in a state in which the light incident side and the exit side have different inclination angles. However, in the following tenth to twenty-ninth embodiments, the structure of the phase difference plate exhibits a good state even when the same oblique angle is formed on the incident side and the outgoing side of the light. Further, when the tenth to twenty-ththth embodiments are limited by limiting the pretilt angle of the liquid crystal, they are as shown in Fig. 22. Further, for comparison, the second comparative example, the third embodiment, and the fourth embodiment are also shown in Fig. 22. In the tenth to twelfth embodiments of FIG. 22, the light emitted from the light source is separated by the color separation means for color separating the three primary colors of RGB, and the first polarizing plate is transmitted to illuminate the liquid crystal on the transparent substrate. A reflective liquid crystal element formed between the active matrix substrate (reflective substrate). Then, the light modulated by the reflective liquid crystal element corresponding to the image data to be displayed is detected by the second polarizing plate arranged in a polarization relationship with the first polarizing plate, and then the projection lens is used. A configuration example of a projection apparatus having an oblique projection optical system (off-axis: 〇ff-ax1S) for enlarging projection. A phase difference plate having a uniaxial anisotropy and a -38 - 1292501 (35) optical axis inclined obliquely is interposed between the reflective liquid crystal element and the second polarizing plate, and the liquid crystal layer pretilt angle of the reflective liquid crystal element At 85 degrees, the liquid crystal azimuth is 45 degrees. The structure in which the P-polarized light is incident on the reflective liquid crystal element and the S-polarized light can be transmitted through the second polarizing plate is common. In the above-described embodiment, the phase difference plate characteristic having the tilt axis has the same angle as the substrate side (light exit side) and the surface side (light incident side), but is configured to have different angles in each embodiment. (50 degrees, 40 degrees or 30 degrees). However, the azimuth angle of the phase difference plate is taken as 270 degrees. Further, in the thirteenth and fourteenth embodiments, the angles of the substrate side (light exit side) and the surface side (light incident side) of the phase difference plate are 10 degrees and 70 degrees, or 70 degrees and 10 degrees, respectively. It is different from the tenth to twelfth embodiments. In the tenth to fourteenth embodiments, the left and right contrast tilts are not displayed, and a uniform display can be displayed, and no interference fringes are observed. Further, as shown in Fig. 22, in the fifteenth to twenty-sixth embodiments, in the projection apparatus having the above-described oblique projection optical system (off-axis), a phase difference having a uniaxial anisotropy and an optical axis inclined obliquely is inserted. The plate is between the first polarizing plate and the reflective liquid crystal element, and the liquid crystal layer of the reflective liquid crystal element has a pretilt angle of 85 degrees, the liquid crystal azimuth angle is 225 degrees, and the incident S is polarized to the reflective liquid crystal element, the second Although the structure in which the polarizing plate can transmit the P-polarized light is common, the pre-tilt angle of the incident side of the phase difference plate, the retardation and the pre-tilt on the exit side are different. That is, in the fifteenth to eighteenth embodiments, the incident side pre-twist angle and the exit side pre-tilt angle of the phase difference plate are both 50 degrees, but the retardations are different from each other. Further, the incident side pretilt of the phase difference plate of the nineteenth to twenty-sixth embodiments is -39 - 1292501. (36) The angle and the exit side pretilt angle are the same in each example, but the angle is in each embodiment. It has a difference of every 10 degrees up to 80 degrees. Further, in the twenty-seventh to twenty-ninth embodiments, the incident side pretilt angle and the exit side pretilt angle of the phase difference plate are all the same at 70 degrees, but the liquid crystal layer pretilt angle of the reflective liquid crystal element is 2 7 The embodiment is 80 degrees, 83 degrees in the 28th embodiment, and 89 degrees in the 29th embodiment. As a result of these states, it is ascertained that when the liquid crystal layer pretilt angle of the reflective liquid crystal element is greater than 89 degrees, the tilt direction of the liquid crystal molecules becomes different when an electric field is applied to the pixel electrode, so that the image is easily generated. Like the defect, when the pretilt angle of the liquid crystal layer of the reflective liquid crystal element is 83 degrees or less, even if it is compensated by the phase difference plate having the tilt axis, the contrast cannot be obtained, and the left and right deviation of the contrast is also generated ( Uneven). Therefore, the liquid crystal layer pretilt angle of the reflective liquid crystal element is desirably 83 to 89 degrees. Next, a third embodiment of the present invention will be described with reference to Fig. 23. 23(A), (B) and (C) are front elevational views, longitudinal cross-sectional views, and side cross-sectional views, respectively, of a main portion showing a third embodiment of the present invention. In the same figure (A) to (C), the surface of the phase difference plate 1 1 1 is adhered to the polarizing plate 1 1 3 by the adhesive layer 1 1 2, and the other side of the phase difference plate 1 1 1 The surface is adhered to the back surface of the glass layer 1 1 5 by the adhesive layer 1 14 . On the surface of the glass layer 115, an anti-reflection layer 1 16 is formed. Further, the phase difference plate 1 1 1 has a disc-like liquid crystal as a basic negative uniaxial anisotropy, and its optical axis is slanted as shown in FIG. 23(B) to be inclined to the die face and parallel to the paper surface direction. As for the transmission axis of the polarizing plate 113, as shown in Fig. 23 (A), it is formed in the downward direction of the upper -40 - 1292501 (37) in the figure, that is, as the phase difference plate 1 11 The optical axis is orthogonal to each other. According to the third embodiment, since the phase difference plate 11 1 is formed so as to be in contact with the polarizing plate 1 1 3 so as not to have excessive surface reflection, it has a characteristic that the transmittance can be improved. Further, at this time, the joining direction of the polarizing plate 1 13 and the phase difference plate can be determined in a clear manner. Further, when the pre-tilt angles of the disc-shaped liquid crystals are different between the retardation plates 1 1 1 , the one having a large inclination angle is adhered to the polarizing plate 1 1 3 . Further, it is preferable that the transmission axis of the polarizing plate 1 1 3 and the optical axis of the phase difference plate 1 1 1 are on the same surface. Further, as shown in Fig. 23, the phase difference plate 11 is adhered to the surface by the glass layer 115 and the adhesion layer 114 which are subjected to the reflection preventing treatment, so that unnecessary interface reflection can be reduced, and as a result, a bright projection can be achieved. . Further, it is possible to suppress an unsharp, distorted (distorted) image caused by the refractive surface caused by the surface concavity. Figs. 24(A) and (B) are views showing the configuration of a fourth embodiment of a projection apparatus using a reflective liquid crystal device according to an embodiment of the present invention in black display and white display. In the projection device 350 of the reflective liquid crystal device according to the fourth embodiment of the present invention, the first polarizing plate 352a for taking out linear polarized light from incident light is incident on the reflective liquid crystal. On the incident light path of the element 351, a phase difference plate 353 having a tilted structure in the axial direction and a second polarizing plate (photodetector) 352b are disposed on the reflected light path from the reflective liquid crystal element 351. . The second polarizing plate 352b is disposed to have a relationship of orthogonal polarization to the one polarizing plate 352a. The reflective liquid crystal element 351 has a transparent substrate 354 and a reflective substrate 355 which are disposed to face each other, and has a liquid crystal layer 356 interposed therebetween. Further, -41 - (38) 1292501, although not shown, a transparent electrode in which a common electrode is formed on the opposite surface of the transparent substrate 354, and a surface on the opposite surface of the reflective substrate 355 is formed in each The MOS transistor formed by the pixel or the driving circuit formed of the TFT or the like and the reflective electrode have a plurality of matrix shapes. As the pixel size, a fine pixel such as ΙΟμπιχΙΟμπι is formed. On the other hand, as the reflective liquid crystal element (die) constituting the liquid crystal layer 356, the nematic liquid crystal has a pretilt angle of 2 to 5 degrees, and the liquid crystal layer has a torsion angle of 80 to 90 degrees, and the transparent substrate 354 side. The liquid crystal alignment azimuth angle has a range of 190 degrees to 200 degrees or 280 degrees to 290 degrees. Further, in the fourth embodiment, the wavelength normalization delay of the liquid crystal layer 356 is set to 0. 35 or more 0. 55 or less. Further, the surface of the transparent substrate 354 and the reflective substrate 355 which are in contact with the liquid crystal layer 356 are provided with an alignment film (not shown) which is formed by rubbing the surface of the polyimide film, for example, to impart alignment to the liquid crystal molecules. The liquid crystal molecules in the initial state have an inclination angle of, for example, about 2 to 5 degrees and a plane azimuth of about 190 to 200 degrees, or 280 to 290 degrees, with respect to the polarization axis of the polarizing plate. The twist angle of the liquid crystal is controlled to be 80 to 90 degrees. Further, Fig. 24 (Α) shows a state in which an electric field is applied to each of the pixel electrodes to display black when the liquid crystal layer 356 is turned on. The same figure (Β) is in a state where an electric field is not applied to each of the pixel electric fields. In the (initial state), a 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 Fig. 25. Fig. 25 (Β) shows the structure of Fig. 24 (Α), (Β) together with the optical axis of the phase difference plate 353, and the same structure as Fig. 24 (A) '(Β) is attached -42- 1292501 (39) The same symbol. In FIGS. 24(A), (B) and FIG. 25(B), the light emitted from a light source (not shown) is first incident on the reflective liquid crystal element 351 by taking only the p-polarized light from the first polarizing plate 352a. . In the case of Fig. 25(A), the direction of vibration of the P-polarized light incident on the reflective liquid crystal element 351 by the first polarizing plate 352a is shown. On the other hand, in the reflective liquid crystal element 351, the alignment direction of the liquid crystal molecules of the liquid crystal layer 356 is made to be in the direction indicated by Π in Fig. 25(A) on the light incident side, and is m in Fig. 25(A) on the side of the reflective surface. The direction shown. The light incident on the reflective liquid crystal element 351 passes through the liquid crystal layer 356 and is reflected by the reflective electrode on the reflective substrate 355, and is again emitted through the liquid crystal layer 3 56 and the transparent substrate 354, and is incident on the axis direction to be inclined. Phase difference plate 35 3 . The phase difference plate 353 which is inclined in the axial direction is arranged so as to be parallel to the in-plane alignment with the direction in which the incident P-polarized light vibrates as shown by IV in Fig. 25(A). That is, the optical axis of the phase difference plate 353 is set to be orthogonal to the transmission axis of the first polarizing plate 352a. The light modulated by the phase difference plate 3 5 3 having the inclination of the optical axis indicated by 359 shown in Fig. 25 (B) is incident on the second polarizing plate (photodetector) 352b. The light detecting direction of the second polarizing plate (photodetector) 352b is indicated by V in Fig. 25(A). When an electric field is not applied to each of the pixel electrodes, or a liquid crystal layer 356 of a threshold voltage is applied to form an OFF (OFF), the incident linear polarized light is modulated in the reflective liquid crystal element 35 1 , and the polarized state is It is rotated and emitted 'and does not pass through the second polarizing plate (photodetector) 352b through the second polarizing plate (photodetector) 352b, and is enlarged and projected onto a shadow screen (not shown). On the other hand, when a sufficient electric field is applied to each of the pixel electrodes to drive the liquid crystal layer 356 to turn on -43-(40) 1292501, the polarization state of the incident light remains unchanged while maintaining the original reflective substrate 35. 5 reflections. At this time, the reflected light is absorbed by the second polarizing plate (photodetector) 352b disposed before the projection lens 357, and thus is formed as shown in FIG. 24(A) and is not incident on the projection lens 35. 7. That is, black 〇 will be displayed. Next, the phase difference plate 353 having the slanting axis will be described in more detail. The phase difference plate 353 having the slanting axis is a negative birefringent compensation plate, for example, disclosed in the specification of US Pat. No. 5,410,422. Or a biaxially-stretched polymer film, or the arrangement of the discotic liquid crystal on the substrate, or the like, which is disclosed in Japanese Laid-Open Patent Publication No. Hei 9-119799 or JP-A No. 2000-32 1576. The ideal form of the phase difference plate 353 is as follows. (1) The phase difference plate 353 is composed of a transparent substrate (transparent support) and an optically anisotropic layer formed of a compound having a dish structure unit disposed thereon. (2) The disc surface of the disc-shaped structural unit of the optically anisotropic layer is inclined with respect 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 depth of the optically anisotropic layer The direction becomes a change 〇(3) The total absolute 値Re 1 of all the retardations of the optical compensation sheet expressed by the formula 5 and the absolute 値Re2 of the liquid crystal layer represented by the formula 6 can satisfy the relationship of the following four equations. 15xRe2^ Rel ^ 0. 6xRe2 4 - 44- (41) 1292501 [But the delay of the above optical compensation sheet is defined as follows, [nl - (n2 + n3) / 2] xd 5 (in the above formula, nl, n2, n3 represents the above optical compensation The refractive index in the three-axis direction of the sheet, and each having a small refractive index in this order, and d is the thickness in nm of the optical compensation sheet), and the retardation of the liquid crystal layer is defined as follows, {m3- (ml+ M2) /2}xd" 6 (in the above formula, ml, m2, m3 represent the refractive index in the triaxial direction of the above liquid crystal layer, and each has a small refractive index in this order, and d / represents the liquid crystal layer Nm conversion thickness)]. Further, as a characteristic of the phase difference plate 353 having the tilt axis, for example, the substrate side angle is 4 degrees, the front side angle is 80 degrees, and the retardation in the film surface direction is about 107 nm. On the other hand, the light incident on the phase difference plate 353 is incident from the larger side of the inclination angle. In the actual system system using the phase difference plate 3 5 3 , the visible angle characteristic obtained by the simulation is as shown in Fig. 25 (C), and the black is sunken when viewed from the azimuth angle of 90 degrees (black display) When the intensity of the light is extremely small, it is excellent in observing the characteristics of the light reflected from the oblique angle of 10 degrees to 30 degrees (the light reflected from the oblique direction). Here, in order to display black color, 5 V was applied to each of the pixel electrodes. Furthermore, in Fig. 25(C), the circle angle drawn by the dotted line (dotted line) of -45 - 1292501 (42) is a circle of 20 degrees, and the circle of the smallest diameter is 20 degrees (others are visible) In the present embodiment, the light intensity of the azimuth angle of 70 to 110 degrees and the polar angle of 0 to 20 degrees is applied to each of the pixel electrodes when a voltage of 5 V is applied to each of the pixel electrodes. As shown by VI in Fig. 26, the black level is extremely good in this angular range, and it is confirmed that light is incident due to the oblique direction, so that a high contrast can be obtained even for the oblique optical system. Further, the incident angle of the light incident on the liquid crystal layer 3 6 6 is about 12 degrees, and the F 投影 of the projection lens 3 5 7 is 2. 4 (At this time, the lens take-in angle is about 12 degrees, so it becomes light with an entrance angle of 0 degrees to 24 degrees and azimuth angle of 78 to 102 degrees). The contrast when projected on the screen is about 900:1. Although there is a slight tilt of the left and right contrasts, they are all in the practical range, and no interference fringes caused by reflections on the surface or the inside of the interface are observed. Next, the phase difference plate 3 5 3 of the fourth embodiment is removed, and the other optical arrangement is the same as that of the embodiment of Fig. 24 as a third comparative example. In the actual projected screen of the third comparative example, the interference phenomenon caused by the reflection on the surface or the inside of the interface was not observed, but the tilt phenomenon of the black level in the left-right direction was observed. The high contrast is 5 00:1, but the low contrast is 100:1. It can be seen that the angular characteristic is formed as shown in FIG. 27, even when the voltage is sufficiently applied to the black display of the pixel electrode, the liquid crystal molecules in the vicinity of the substrate are maintained in the horizontal direction due to the influence of the alignment film, so that the contrast in a specific direction is changed. Not good. In the third comparative example, the reflection-side substrate is set to 15 degrees, and the transparent electrode-side plate is set to 11 degrees, so that it can be observed at a square of -46 - 1292501 (43) and an angle of 〇 to 90 degrees and In the range of 180 degrees to 270 degrees, the black level becomes poor, and the azimuth angle of the third comparative example is 70 degrees to 110 degrees, and the intensity of the black display of the polar angle of 0 degrees to 2 5 degrees is as shown in FIG. The 'shows that the pole angle is small (when it is not too tilted), the black level is good, but as the pole angle becomes larger, especially when the azimuth angle is deflected from 90 degrees (in that case, it is assumed to be from 270 degrees) In the state of the incident light, the light intensity is rapidly increased, that is, although the black display is performed, a good black level cannot be obtained. This condition means that the black level is inclined to the left and right direction on the projected picture, so that it has a contrast on the left and right. On the other hand, in the case of color synthesis, since the characteristics of the three reflective liquid crystal panels are not uniform, it is observed that the color is uneven and extremely remarkable. In the fourth embodiment, the phase difference plate 353 is interposed between the reflective liquid crystal element 351 and the second polarizing plate 3 5 2b in the MTN mode, so that even in the third comparative example, In the oblique optical system, although there are a few cases in which the left and right contrasts are inclined, they are all within the practical range, and have the characteristic that no interference phenomenon due to reflection on the surface or the inside of the interface is observed. Next, a fifth embodiment of the present invention will be described. The fifth embodiment is the same optical arrangement as that of Figs. 24(A) and (B). However, the reflective liquid crystal element 351 uses a SCTN mode reflective liquid crystal element, which is different from the fourth embodiment. That is, the liquid crystal molecules as the liquid crystal layer 365 are composed of nematic liquid crystals, and the pretilt angle is 2 degrees to 5 degrees, and the twist angle of the liquid crystal layer 3 5 6 is approximately -47 - 1292501 (44) As 60 degrees. Further, the liquid crystal alignment azimuth angle of the transparent substrate 354 side and the reflective substrate 35 5 side is set to be about 150 degrees, about any one of about 210 degrees, or about 340 degrees and about 30 degrees. Further, the wavelength normalization delay of the liquid crystal layer 365 is 〇·55 or more and 0. 65 or less. On the surface of the transparent substrate 3 5 4 and the reflective substrate 35 5 which are in contact with the Chang layer 3 5 6 , an alignment film coated with a surface of the polyimide film is applied to impart alignment to the liquid crystal molecules (not shown). Show). In the actual system of the fifth embodiment, the visible angle characteristic obtained by the simulation is as shown in FIG. 29 'when viewed from the azimuth angle of 90 degrees, the black color sinks (the light intensity in black display is extremely small), and Observing the characteristics of the light reflected from the oblique incident light from the polar angle of 15 to 20 degrees is extremely excellent. Here, '5 V is applied to each pixel electrode for black display. Further, in the fifth embodiment, when 5 V is applied to each of the pixel electrodes, the light intensity is formed at an azimuth angle of 70 to 110 degrees, and the polar angle is from twentieth to 25 degrees, as shown in FIG. It is confirmed that the black level is extremely good in this angular range, and since the light is incident due to the inclination, an extremely high contrast can be obtained even in the oblique optical system. Further, the incident angle of the light incident on the reflective liquid crystal element is about 12 degrees, and the F 投影 of the projection lens 3 5 7 is 2. 4 (At this time, the lens take-up angle is about 12 degrees, so that it can be taken into the visible angle, the polar angle is 〇~24 degrees, and the azimuth is in the range of 7 8~1 0 2 degrees). The contrast is 1 〇〇〇: 1 and it is excellent without the contrast of the left and right. No disturbances accompanying reflections on the surface or inside the interface were observed. Furthermore, the liquid crystal alignment direction of the SC TN mode is for the incident side polarized light -48-1292501 (45) plate (Fig. 24, 3 5 2a) or the exit side polarizing plate (Fig. 24, 3 5 2b) due to the configuration of the liquid crystal cell. Since the upper and lower directions are symmetrical, even in the same twist state, eight modes are conceivable. However, when the twist angle is 60 degrees, it is desirable to set the liquid crystal alignment azimuth angle of the transparent substrate side and the reflective substrate side to about 15 0 degrees, any one of about 2 1 0 degrees, or formed to be about 3 3 0 degrees and about 30 degrees. The reason is set to be such that the visible angle can be widened. In addition, the phase difference plate 3 5 3 is removed, and the other optical arrangement is the same as the fourth comparative example of the fifth embodiment, and the actual projected picture is 5 0 : 1 at a high contrast, but at a low level. The contrast is 3 0 : 1. The fourth and fifth embodiments described above can also be said to be the same as those shown in Figs. 21(A) to (E). 31(A) to (E), the phase difference plate 1 〇1 indicates the phase difference plate 3 5 3 described above, and the mode indicates that the liquid crystal molecules are gradually inclined in the thickness direction of the film surface. arrangement. That is, the phase difference plate 10 1 (353) has its optical axis formed parallel to the paper surface in FIG. 31, and the optical axis is inclined with respect to the phase difference plate film surface, but the optical axis is made corresponding to the thickness from the film surface. The tilt angle is formed to gradually change. Further, the polarizing plates 102, 104, 105, 106 correspond to the second polarizing plate 352b° as described above, and use S-polarized light for incident light incident on the phase difference plate, and have a negative optical property. The phase difference plate 1 0 1 (353) which is inclined in the axial direction and which is inclined obliquely is made parallel to the transmission axis of the adjacent polarizing plates 102, 104, 105, thereby lowering the black level and increasing the contrast, and The wide range of angles (contrast coefficients) can be obtained with sufficient expansion. Furthermore, the present invention is not limited to the above-described fourth and fifth embodiments -49-1292501^(46), and for example, a phase difference plate whose optical axis is inclined obliquely may be inserted into the first polarizing plate 3 52a and Between the reflective liquid crystal elements 351. At this time, the optical axis of the phase difference plate is set to be orthogonal to the transmission axis of the adjacent first polarizing plate 352a. Further, although the incident direction of the light is also reflected when the embodiment is reflected from the lower surface toward the upper surface, that is, the state is emitted from the azimuth angle of 270 degrees and is emitted toward the azimuth angle of 90 degrees, the light is emitted from the 90-degree direction or the other direction. Irradiation, as long as the alignment direction of the liquid crystals and the optical arrangement of the phase difference plates are performed, the same effect can be obtained. [Effects of the Invention] As described above, according to the present invention, it is possible to insert a phase difference plate having a uniaxial anisotropy and tilting the optical axis toward the film surface obliquely in a polarizing means and Between the reflective liquid crystal elements or between the reflective liquid crystal element and the light detecting (analysis) means, the optical axis of the phase difference plate is set to be a transmission axis of the polarizing means or the light detecting means adjacent to the phase difference plate. The black level can be lowered, so that a projection image (image) with a high contrast ratio (contrast ratio) can be obtained, and an angular range in which sufficient contrast can be obtained can be expanded. (2) It is possible to analyze only the predetermined P-polarized light (polarized light) or S-polarized light by polarizing means and light detecting means without using polarized beam splitting (PBS), and thus has optical system capability of PBS. A bright optical system is realized at a low cost. (3) Since the PBS is not used, it is necessary to incident light in the oblique direction to the -50-(47) 1292501 reflective liquid crystal element, but it can be adjusted to be most appropriate only around the incident angle, so that it is extremely High contrast ratio. (4) Since the conditions of the polarizing plate for constituting the polarizing means are not strict (wide), various polarizing plates can be applied. (5) The polarizing means and the light detecting means are independent and have a Nicole relationship. Therefore, projection interference fringes are not generated on the screen, and after color separation, there are polarizing means and light detecting means, so that There is a problem in the color separation and the birefringence of the color separation and the reduction of the purity of the polarized light of the device which performs color synthesis after the light detection, and therefore, it is stable to heat or the like. (6) The phase difference plate and the light-receiving means or the light-detecting means which are close to each other are configured to be integrally fixed so that unnecessary surface reflection can be eliminated, and the transmittance can be improved. (7) The phase difference plate is configured to adhere to the structure in which the anti-reflection layer is formed on the back surface of the surface, so that unnecessary interface reflection can be reduced, so that bright projection can be performed, and refraction caused by unevenness of the surface can be suppressed. The resulting image is blurred and distorted (distorted). (8) When a reflective liquid crystal element of the NW mode is used, S-polarized light is used for incident light, and a phase difference of optically negative uniaxial anisotropy and optical axis tilting obliquely toward the film surface is inserted. The plate is disposed between the polarizing means and the reflective liquid crystal element, or between the reflective liquid crystal element and the light detecting means, and sets the optical axis of the phase difference plate and the transmission of the polarizing means or the light detecting means adjacent to the phase difference plate The axes are orthogonal so that the black level can be lowered, so that a projection image with a high contrast ratio can be obtained, and an angular range that can sufficiently obtain contrast can be widened. -51 - 1292501 (48) (9) Since the drive can be compared at a low voltage, the drive transistor can be made small and high resolution can be achieved. (10) Since the voltage dependency of the chromaticity is small, the driving of the lower voltage becomes feasible, and the high-speed responsiveness is excellent, and 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 by 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 Fig. 1 (A) and Fig. 1 (B) are block diagrams showing first and second embodiments of the present invention. Fig. 2 (A) and (B) are views showing the configuration of a projection apparatus according to the first and second embodiments of the present invention. Fig. 3 is a graph showing changes in transmittance with respect to an angle including only the plane of the axial direction of the phase difference plate having the inclined axis shown in Fig. 2. Fig. 4 is a view showing the visible angle characteristic of the first embodiment obtained by the projection apparatus shown in Fig. 2 in the simulation. Fig. 5 is a view showing a visible angle characteristic of a second embodiment of the present invention. Fig. 6 is a view showing a visible angle characteristic of a first comparative example in which a phase difference plate having an axial direction is not inserted. Fig. 7 is a key explanatory diagram of the visible angle characteristic. Fig. 8 (A) and (B) are views showing the configuration of a projection apparatus -52 - 1292501 (49) according to a third embodiment of the present invention. Fig. 9 is a graph showing changes in transmittance with respect to an angle including only the face of the phase difference plate axis direction having the tilt axis of the third embodiment. Fig. 10 is a view showing the visible angle characteristic obtained by the simulation of the projection apparatus of the third embodiment. Figure 11 (A) ~ (G) is in Rel / Re2 = 0. 13~0. 8 o'clock visible angle characteristic map. Fig. 12 is a view showing a visible angle of the second comparative example. Fig. 13 (A) and (B) are views showing the configuration of a fourth embodiment of the projection apparatus of the present invention. 14(A) to 14(D) are diagrams showing the relationship between the optical axis of the phase difference plate of the fourth embodiment of the present invention and the liquid crystal alignment direction of the reflective liquid crystal element, the detailed structure of the phase difference plate, the visible angle characteristic, and the fourth aspect of the present invention. A structural diagram of an embodiment. 15(A) to 15(D) are diagrams showing the relationship between the optical axis of the phase difference plate of the fifth embodiment of the present invention and the liquid crystal alignment direction of the reflective liquid crystal element, the detailed structure of the phase difference plate, the visible angle characteristic, and the fifth aspect of the present invention. A structural diagram of an embodiment. Figs. 16(A) to 16(C) are diagrams showing the relationship between the optical axis of the phase difference 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 a configuration diagram of the sixth embodiment of the present invention. Fig. 17 (A) to (C) show the relationship between the optical axis of the phase difference plate of the seventh embodiment of the present invention and the liquid crystal alignment direction of the reflective liquid crystal element, and the angle characteristics and the configuration diagram of the seventh embodiment of the present invention can be seen. 18(A) to 18(C) are diagrams showing the relationship between the optical axis of the phase difference plate of the eighth embodiment of the present invention and the liquid crystal alignment direction of the reflective liquid crystal element, and the angle is -53-129952, (50) and the present invention. A block diagram of the eighth embodiment. Fig. 19 (A) to (C) show the relationship between the optical axis of the phase difference plate of the ninth embodiment of the present invention and the liquid crystal alignment direction of the reflective liquid crystal element, and the angle characteristics and the configuration diagram of the ninth embodiment of the present invention are visible. Fig. 20 is a view showing the results of aggregating the first to ninth embodiments of the present invention and the first comparative example. Fig. 2 (A) to (E) are diagrams showing ideal examples and non-ideal examples in each of the retardation plate and the polarizing plate. Fig. 22 is a view showing the results of aggregating the first to ninth embodiments of the present invention and the second comparative example. 23(A) to (C) are configuration diagrams of a third embodiment of the present invention. Figs. 24(A) and (B) are views showing the configuration of a projection apparatus according to a fourth embodiment of the present invention. 25(A) to 25(C) are diagrams showing the relationship between the incident light vibration direction of the reflective liquid crystal device according to the fourth embodiment of the present invention, the optical axis of the phase difference plate, and the liquid crystal alignment direction of the reflective liquid crystal element, and the embodiment of the present invention. Structure diagram and visible angle characteristics. Fig. 26 is a view 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 the visible angle characteristic of the third comparative example. Fig. 28 is a graph showing the relationship between the azimuth angle, the polar angle and the light intensity in the third comparative example. Figure 29 is a view showing a visible angle characteristic of a fifth embodiment of the present invention. Fig. 30 is a graph showing the relationship between the azimuth angle, the polar angle, and the intensity of light (51) 1292501 in the fifth embodiment of the present invention. Fig. 3 (A) to (E) are diagrams showing ideal and non-ideal examples in each of the retardation plate and the polarizing plate. Figure 32 is a block diagram showing an example of a prior projection device. Figure 3 is a block diagram of another example of a prior projection device. Fig. 34 (A) and (B) are structural views of a prior projection apparatus in which an optical system is colored. Figure 35 is a block diagram showing still another example of the prior projection apparatus. [Description of Symbols] A1: Light source A 2: Lens group A3: Color separation optical system A 4 : Polarization means A5, B1, 53, 63, 73, 81, 86, 91, 95, 101, 111, 35 3: Phase Differential plate A6, 51, 61, 71, 351: Reflective liquid crystal element A7: Light detecting means A8: Color synthetic optical system A9, 57, 67, 77, 357: Projection lens 50, 60, 70, 35 0: Related Projection devices 52a, 62a, 72a, 352a of the embodiment: first polarizing plates 52b, 62b, 7 2b, 352b: second polarizing plate (photodetector) 54, 64, 74, 354: transparent substrate 129251 (52) ( Electrode) 55, 65, 75, 355: reflective plate 5 6, 66, 76, 3 5 6 : liquid crystal layer 1 1 2, 1 1 4 : adhesive layer 1 13: polarizing plate 1 1 5 : glass layer 1 1 6 : Surface reflection preventing layer -56-

Claims (1)

1292501 ;1 96. 8. 2 4 ....I (1) Pick up, apply for patent scope No. 92108 148 Patent application Chinese patent application scope amendments Amendment 24 of August 1996 1 · A use of reflective liquid crystal elements The projection device transmits the light emitted from the light source to the reflective liquid crystal element between the transparent substrate and the reflective substrate through the polarizing means, and the reflective liquid crystal element is modulated by the reflective image liquid crystal element. The reflected light of the reflective liquid crystal element is detected by a photodetecting means arranged in a crossed nicol relationship with the polarizing means, and the light detected by the photodetecting means is expanded by projection transmission. A projection apparatus using a reflective liquid crystal element for projecting an oblique projection optical system, wherein the polarizing means and the reflective liquid crystal element have a uniaxial anisotropy, and the optical axis is inserted obliquely to the film surface. a phase difference plate, wherein the optical axis of the phase difference plate is set to be opposite to the polarizing means or the light detecting hand adjacent to the phase difference plate The transmission axis is orthogonal, and the phase difference plate has a substantially negative uniaxial anisotropy of the disk-shaped liquid crystal, and the optical axis of the disk-shaped liquid crystal is on the incident side of the light of the film surface, and the film surface is In other words, the film surface is inclined at a temperature of 4 degrees or more and 10 degrees or less, and the film surface is inclined at 70 degrees or more and 80 degrees or less on the light emitting side of the film surface, and the retardation of the film surface direction is 7 1 . In the above-mentioned polarizing means, the polarized light is obliquely incident on the inclined side of the light of the disc-shaped liquid crystal, and the optical axis of the disc-shaped liquid crystal is obliquely inclined in the oblique direction. . 2. A projection device using a reflective liquid crystal element, wherein light emitted through a light source is transmitted through a polarizing means to a reflective liquid crystal element formed between a transparent substrate and a reflective substrate and held by a liquid crystal layer, and the reflective liquid crystal element The reflected light from the reflective liquid crystal element modulated by the corresponding image data is detected by a photodetecting means arranged in a crossed nicol relationship with the polarizing means, and the light is detected by the photodetecting means. A projection device using a reflective liquid crystal element by projecting an oblique projection optical system that expands projection, wherein the polarizing means and the reflective liquid crystal element have uniaxial anisotropy, and the optical is inserted a phase difference plate in which the axis is inclined obliquely to the film surface, and an optical axis of the phase difference plate is set to be orthogonal to a polarization axis of the polarizing means adjacent to the phase difference plate or the light detecting means, and the phase difference plate Is such that the disc-shaped liquid crystal is substantially negative uniaxial anisotropy, and the optical axis of the disc-shaped liquid crystal is in the film surface In the incident side of the light, the film surface is inclined at 4 degrees or more and 10 degrees or less, and the film surface of the film surface is 70 degrees or more and 80 degrees or less on the light emitting side of the film surface. The slanting, the retardation of the film surface direction is from 71 nm to 142 nm, and the reflected light from the reflective liquid crystal element modulated by the reflective liquid crystal element corresponding to the image data is incident on the slanted liquid crystal obliquely. On the inclined side, the optical axis of the disk-shaped liquid crystal is inclined, and the s-polarized light is emitted by the light detecting means. 3 - A projection device using a reflective liquid crystal element, the light emitted through the light source -2- 1292501 (3) is transmitted through a polarizing means, and is incident between the transparent substrate and the reflective substrate, and the liquid crystal layer is formed into a reflective liquid crystal element. In the reflective liquid crystal element, the reflected light from the reflective liquid crystal element modulated by the corresponding image data is detected by a photodetecting means arranged in a crossed nicol relationship with the polarizing means. A projection device using a reflective liquid crystal element that projects light transmitted through the light detecting means by projecting through an oblique projection optical system that expands projection, and is characterized in that the polarizing means and the reflective liquid crystal element have a single The axially opposite phase is inserted into the phase difference plate in which the optical axis is inclined in the oblique direction with respect to the film surface, and the optical axis of the phase difference plate is set to be opposite to the polarization axis of the retardation plate or the transmission axis of the light detecting means. Orthogonal, the phase difference plate has a negative uniaxial anisotropy for the disc liquid crystal, and the optical axis of the disc liquid crystal On the incident side of the light of the film surface, the film surface is inclined at 4 degrees or more and 10 degrees or less, and the film surface of the film surface is 70 degrees on the film surface. The degree of the film surface is inclined at 80 degrees or less, and the retardation in the film surface direction is 71 nm or more and 142 nm or less, and the polarized light is obliquely incident on the inclined side of the light of the discotic liquid crystal by the polarizing means, and the dish is formed. The optical axis of the liquid crystal is tilted. 4. The projection apparatus using a reflective liquid crystal element according to any one of the preceding claims, wherein the reflective liquid crystal element is a nematic liquid crystal having a negative dielectric anisotropy. The pre-tilt angle is 80 degrees to 89 degrees, and is set to an azimuth angle (45 + 90xn) for incident polarization (only η is an integer angle), and the optical axis of the phase difference plate is set to flat -3- 1292501 (4) Acting on the vibrating surface of the incident p-polarized light. The projection device of the reflective liquid crystal element according to any one of the above-mentioned claims, wherein the polarizing means is configured to pass the S-polarized 峙 characteristic, and the phase difference plate is The reflective liquid crystal element is provided between the polarizing means and the reflective liquid crystal element, wherein the dielectric liquid is negatively neat nematic liquid crystal, and is approximately at a pretilt angle of 80 to 8 9 degrees, and is set for incident polarization. The azimuth angle (45 + 90xn) (where η is an integer angle) is set such that the optical axis of the phase difference plate is parallel to the surface of the vibration plane of the incident S-polarized light. 6. The projection apparatus using a reflective liquid crystal element according to any one of the above-mentioned claims, wherein the phase difference plate has a tilt of the disc-shaped liquid crystal, and is disposed opposite to each other. The polarizing means or the side of the light detecting means. 7. The projection apparatus using a reflective liquid crystal element according to any one of claims 1 to 3, wherein the phase difference plate is integrally fixed to the polarizing means or the light detecting means. The projection device using a reflective liquid crystal element according to any one of the above-mentioned claims, wherein the phase difference plate is adhered to a back surface of a glass plate on which an antireflection layer is formed on the surface. </ RTI> </ RTI> <RTIgt; </ RTI> <RTIgt; </ RTI> <RTIgt; </ RTI> <RTIgt; </ RTI> <RTIgt; </ RTI> <RTIgt; </ RTI> <RTIgt; A projection device using a reflective liquid crystal element according to any one of claims 1 to 3, wherein the reflective liquid crystal cell -4- 1292501 (5) pre-tilts the nematic liquid crystal The angle is 2 degrees to 5 degrees, the twist angle of the liquid crystal layer is 80 degrees to 90 degrees, and the liquid crystal alignment azimuth angle of the transparent substrate is in the range of 190 degrees to 200 degrees or even 280 degrees to 290 degrees, and The wavelength normalization retardation of the liquid crystal layer is 0.35 or more, and the MTN mode is 0.55 or less. The projection device using a reflective liquid crystal element according to any one of claims 1 to 3, wherein the reflective liquid crystal element has a pretilt angle of 2 to 5 degrees. The twist angle of the liquid crystal layer is about 60 degrees, and the liquid crystal alignment azimuth angle of the transparent substrate side and the reflective substrate side is set to be any one of about 15 degrees and about 2 μ degrees, or In the case of any of about 3300 degrees and about 30 degrees, the wavelength normalized retardation of the liquid crystal layer is 0.55 or more, and the SCTN mode is 0.65 or less. -5- 1292501 Lu, (1), the designated representative figure of this case is: Figure 1 (2), the representative symbol of the representative figure is a simple description: Al · light source A2: lens group, · A3: color separation optical system A4: Polarization means A5JBI: Phase difference plate A6: Reflective liquid crystal element ~ A7: Detection (polar) means." A8: Color synthesis optical system A9: Projection lens · 柒, if there is a chemical formula in this case, please reveal the best display invention Characteristic chemical formula: -3-