JP2008164859A - Image producing engine and projection apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image producing engine which improves image degradation such as resolution degradation and contrast performance degradation due to wave front aberration and to provide a projection apparatus having the image producing engine. <P>SOLUTION: The image producing engine has a light valve which carries out light modulation of incident light from a light source emitting two or more colors of light while transmitting or reflecting the light and an optical device which is provided on an optical path of exit light from the light valve and includes a polarizer and a wavelength plate. The polarizer and a wavelength plate constituting the optical device are respectively held between glass base materials via an adhering layer. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an image forming engine and a projection apparatus using a display element that displays light by controlling light in units of pixels using a light valve.

  In recent years, the demand for higher definition of displays and projectors has been addressed by increasing the number of pixels on the panel. Regarding panel resolution, VGA (video graphic array) to S-VGA (super-video graphic array) and XGA (extended graphic array) have become mainstream, and there are also panels that support the number of pixels of SXGA (super extended graphic array). It has appeared on the market as a product.

  In recent years, a projection apparatus using a panel having a number of pixels compatible with HDTV (high-definition television) or a number of pixels of QXGA (quad extended graphic array) that is four times the number of XGA has been put into practical use. It is desired to improve display performance, resolution, and contrast.

  Projector engines are generally configured with a polarizing element in order to achieve the purpose of improving contrast. In the RGB three-plate system using the three primary colors of light, R (red), G (green), and B (blue), a dichroic prism is used to combine the three colors. In order to improve the reflection characteristics, the polarization direction is changed and incident on the dichroic prism. Specifically, in order to efficiently reflect red or blue light, it is better to use S-polarized light, and depending on the direction of optical path separation between illumination light and panel image light, it becomes P-polarized light. A 90-degree polarized light is rotated using a 1 / 2λ plate or the like.

  As conventional projector apparatuses, the inventions disclosed in Patent Documents 1 to 3 are known.

  In patent document 1, the structure which affixed the film-form wavelength plate or the polarizing plate on the glass substrate is employ | adopted. A sectional configuration of such a configuration is shown in FIG. The polarizing plate on the film is affixed to the glass substrate through an adhesive member as shown in FIG. When the transmitted wavefront aberration of such an optical element was evaluated, distributions as shown in FIGS. 18A and 18B were obtained. The wavefront aberration measuring instrument used for the evaluation is an existing optical wavefront aberration evaluating machine. The opening width is an area of approximately 40 mm square. The color density is shown in proportion to the amount of wavefront aberration. The difference between white and black was about 3λ. There is a local optical path difference, not a gentle change. Since the projection light passes through a certain part, it can be determined that the wavefront aberration per unit area of the part has a larger value.

  As is clear from FIGS. 18A and 18B, even when the film is attached to one glass substrate, the optical path difference at the wavelength level of the adhesive (for example, , Light beam A, light beam B, etc.), the difference in the optical path length at the wavelength level occurs, and the amount of wavefront aberration increases and the wavefront is disturbed. In either of FIGS. 18A and 18B, the amount of transmitted wavefront aberration is large in the peripheral portion so that no interference fringes appear, and the influence on the resolution performance is high.

  Further, Patent Document 2 has a configuration in which a wave plate configured by sandwiching two glasses is disposed, and a surface opposite to the wavelength film in at least one of the two glasses is a convex surface. Are listed. As described above, an air layer may be formed between the two glasses and the wave plate, and aberration is generated due to a change in the refractive index due to air.

Further, in Patent Document 3, the polarizing film member 1082 is sandwiched between heat resistant optical members 1081a and 1081b. In order to improve the heat resistance, a configuration in which the glass is sandwiched between heat resistant glasses is adopted for the problem that resolution and contrast decrease due to deterioration of polarization characteristics due to thermal deformation. In this way, an air layer may be formed between the two glasses and the polarizing plate, and aberration is generated due to a change in refractive index due to air.
JP 2001-264744 A Japanese Patent No. 3365618 JP 2002-116502 A

  In the image forming engine as described above, a configuration having a member of a polarizer and a wave plate between the panel and the color combining prism is essential. However, there is a problem that a compact engine can be constructed, and the polarizing plate arranged for improving the contrast causes the imaging light to be disturbed. In other words, due to the influence of optical elements composed of polarizing plates and wave plates arranged in the optical path, the adverse effect that contrast performance deteriorates due to resolution degradation and surface reflection due to an increase in the interface is a demand for improved performance. Along with it has been close-up.

  In view of such problems, the present invention provides an optical element capable of preventing optical degradation such as low resolution and degradation of contrast performance, and an image forming engine and a projection apparatus including the optical element. It is aimed.

  In order to achieve the above object, the invention according to claim 1 is a light source that emits light of a plurality of colors, a light valve that modulates light by transmitting or reflecting incident light from the light source, and a light valve that emits light from the light valve. An imaging engine provided on an optical path of outgoing light and having an optical element including a polarizer or a wave plate, wherein at least one of the polarizer and the wave plate constituting the optical element is an adhesive layer It is characterized by being sandwiched by a glass substrate via

  According to a second aspect of the present invention, in the imaging engine according to the first aspect, the optical element is sandwiched between the first glass substrate and the second glass substrate on both sides of the polarizer via an adhesive layer. And a phase modulation element sandwiched between the third glass substrate and the fourth glass substrate via an adhesive layer on both sides of the wave plate.

  According to a third aspect of the present invention, in the imaging engine according to the first aspect, the optical element is sandwiched between the first glass substrate and the second glass substrate on both sides of the polarizer via an adhesive layer. In addition, both sides of the wave plate are sandwiched between the second glass substrate and the third glass substrate through an adhesive layer.

  According to a fourth aspect of the present invention, in the image forming engine according to the first aspect, the optical element is disposed so that the polarizer and the wave plate are disposed adjacent to each other via the adhesive layer, and each of the optical elements faces the adjacent surface. The surface is sandwiched between a first glass substrate and a second glass substrate provided via an adhesive layer.

  According to a fifth aspect of the present invention, in the imaging engine according to the first aspect, the polarizer is composed of a metal pattern having a pitch equal to or smaller than the wavelength of the emitted light, and the optical element is bonded to both sides of the wave plate. Sandwiched between a first glass substrate disposed on the light valve side through a layer, a second glass substrate symmetrically disposed through the first glass substrate and a wave plate, and The light glass side surface of the first glass substrate is provided with a polarizer having a metal pattern.

  According to a sixth aspect of the present invention, there is provided a light source that emits light of a plurality of colors, and a light valve for each of the plurality of colors that is provided corresponding to each color light from the light source and transmits or reflects incident light of each color to modulate light. A color synthesizing element that synthesizes light emitted from each color light from the light valve, and an optical element that is provided on an optical path between the light valve and the color synthesizing element and includes a polarizer and a wave plate. An image engine, wherein an optical element includes a polarizing element in which both sides of a polarizer are sandwiched between glass substrates via an adhesive layer, and a glass substrate and a color synthesizing element via a wavelength plate via the adhesive layer. And a phase modulation element sandwiched between the two.

  According to a seventh aspect of the present invention, in the imaging engine according to the sixth aspect, the optical element is sandwiched between the first glass substrate and the second glass substrate on both sides of the polarizer via an adhesive layer. And a phase modulation element sandwiched between the third glass substrate and the color synthesis element via an adhesive layer on both sides of the wave plate.

  The invention described in claim 8 is the imaging engine according to claim 6, wherein the optical element is sandwiched between the first glass substrate and the second glass substrate on both sides of the polarizer via an adhesive layer. In addition, both sides of the wave plate are sandwiched between the second glass substrate and the color synthesis element through an adhesive layer.

  According to a ninth aspect of the present invention, in the imaging engine according to the sixth aspect of the present invention, the optical element is arranged such that the polarizer and the wave plate are disposed adjacent to each other via the adhesive layer, and are opposed to the adjacent surfaces. It is characterized in that it is sandwiched between a glass substrate and a color synthesis element provided on the surface via an adhesive layer.

  According to a tenth aspect of the present invention, in the imaging engine according to the first aspect, the polarizer is composed of a metal pattern having a pitch equal to or smaller than the wavelength of the emitted light, and the optical element is bonded to both sides of the wave plate. Sandwiched between a first glass substrate disposed on the light valve side via a layer, and a color composition element disposed symmetrically via the first glass substrate and a wave plate, and the first glass substrate It comprises a polarizer having a metal pattern on the light valve side surface of the glass substrate.

  According to an eleventh aspect of the present invention, there is provided an image forming engine according to any one of the first to tenth aspects, an illumination optical system, and a projection optical system that enlarges and projects an image formed by the image forming engine. It is a projection apparatus which has.

  ADVANTAGE OF THE INVENTION According to this invention, the optical element which reduces optical degradation, such as image degradation by a wavefront aberration, can be provided.

This embodiment improves the deterioration of wavefront aberration, which has been a problem for optical elements in which film-like polarizing plates, wavelength plates, etc. are affixed to a single glass substrate, or polarizing plates that are simply sandwiched between glass substrates. The purpose is to do. More specifically, the object is to provide a more compact image forming engine, to reduce the air interface as much as possible to prevent contrast deterioration due to surface reflection, and to obtain a high quality image.
This reduces the amount of transmitted wavefront aberration of the optical element arranged between the panel and the projected image, thereby realizing high resolution projection while maintaining the projected image quality.

  Hereinafter, an image forming engine and a projection apparatus according to the present embodiment will be described with reference to the drawings. The present embodiment is not limited to the one described below, and various modifications can be made without departing from the spirit of the present embodiment.

  1 and 2 are diagrams schematically showing the image forming engine of the present embodiment. FIGS. 1A and 1B are diagrams showing an image forming engine when a reflective panel is used, in which FIG. 1A shows a top view and FIG. 1B shows a side view seen from the projection lens side. FIG. 2 is a diagram showing an image forming engine when a transmissive panel is used.

  The image forming engine according to the present embodiment includes three light valves 11R, 11G, and 11B corresponding to three colors of red (R), green (G), and blue (B), and an optical path that extracts only panel image-modulated light. A color synthesizing element (dichroic prism) 15 for synthesizing images formed by separating elements (PBS: polarization beam splitter) 12R, 12G, 12B and light valves (11R, 11G, 11B) corresponding to R, G, B Is an image creation engine.

  The reflective panel image forming engine shown in FIG. 1 includes a light valve 11, a polarizing beam splitter (PBS) 12, a polarizing element 13, a phase modulation element 14, a dichroic prism 15, and a color reflecting film (dichroic film). 16 and a projection lens 17. The light valve 11, the polarization beam splitter (PBS) 12, the polarization element 13, and the phase modulation element 14 are respectively red (R), green (G), and blue (B) that are the three primary colors of light. Correspondingly provided. The color reflection films 16 are provided for red and blue, respectively, and are arranged so as to cross the dichroic prism 15 (see FIG. 1A).

  2 includes a light valve 21, a polarizing element 23, a phase modulation element 24, a dichroic prism 25, a color reflection film (dichroic film) 26, a projection lens 27, and the like. It has. Unlike the reflective type of FIG. 1, the transmission type light valves 21R, 21G, and 21B are provided, and the PBS 12 is not necessary.

  Although the projection lens 17 is illustrated in FIG. 1, the projection lens 17 can be made unnecessary by viewing an image displayed on the panel by viewing the liquid crystal panel from the projection lens 17 side. Although not shown in FIG. 1, illumination light corresponding to each of the R, G, and B panels may be irradiated to each panel and enlarged and projected by a projection lens or the like.

  The light valves 11R, 11G, and 11B can be applied to any spatial modulation element that controls polarization, such as a transmissive liquid crystal panel or a reflective liquid crystal panel. The light valve controls the polarization according to the image signal, and an image is formed via an optical path separation element such as the polarization beam splitter 12.

  Here, as shown in FIG. 4 to be described later, a polarizing element 13 in which a polarizing plate (polarizer) is sandwiched between glass substrates is arranged on the front side of incidence on the optical path between the light valve 11 and the dichroic prism 15. Yes. The light transmitted through the polarizing element 13 is rotated by 90 degrees in the polarization direction by the phase modulation element 14 having a 1 / 2λ (wavelength) plate sandwiched between glass substrates, and is incident on the dichroic prism 15.

  At this time, incident light from the red light valve 11R and the blue light valve 11B is reflected by the red reflecting film 16R and the blue reflecting film 16B in the dichroic prism 15, respectively. The light from the green light valve 11G passes through the dichroic prism 15. In this way, the lights from 11R, 11G, and 11B are combined on the exit side (exit) of the dichroic prism 15, and a full color image can be obtained.

  FIG. 3 is a diagram showing an image forming engine in the case where a gold wire lattice type PBS (32R, 32G, 32B) is used instead of the glass PBS. In this case, the influence of skew rays is eliminated and the contrast is greatly improved.

  A feature of the present embodiment is that both the polarizing element 13 and the phase modulation element 14 are integrated with the glass substrate via an adhesive member (adhesive layer). This feature will be described with reference to FIG.

  FIG. 4 is a diagram schematically showing a polarizing element in which a polarizer is sandwiched between adhesive members using a glass substrate. The polarizing element 13 of this embodiment includes a polarizer 41, a first glass substrate 42a, a second glass substrate 42b, a first adhesive layer 43a, and a second adhesive layer 43b.

  The first glass base material 42a and the second glass base material 43b may be any base material as long as it is transparent to the wavelength band of the display image. For example, BK7, white plate glass, sapphire substrate, etc. are suitable. . Of course, it is preferable that the flatness is maintained to some extent, and a plastic member or the like may be used.

  Here, a configuration in which the polarizer 41 is sandwiched is described, but the polarizer 41 may be replaced with a wave plate. By replacing with a wave plate, the configuration of the phase modulation element 14 of the present embodiment is obtained.

  Further, the amount of the adhesive member (the first adhesive layer 43a and the second adhesive layer 43b) may be adjusted so that the distance D between the first glass base material 42a and the second glass base material 42b is kept constant. . Alternatively, a polarizer or a wave plate may be sandwiched by following a glass substrate whose flatness is ensured in advance, and may be bonded and solidified.

  Since the optical path lengths of the light beams A ′ and B ′ shown in FIG. 4 are substantially the same by keeping the distance D constant and matching the refractive indexes of the polarizer, the wave plate, and the adhesive member, low transmission It can be the amount of wavefront aberration.

  In the conventional configuration, for example, the wave plate attached to one side has the configuration as shown in FIG. 19 described above, and the improvement of the resolution performance is hindered by the deterioration of the wavefront aberration.

Such an optical element was mounted on an image forming engine to evaluate the resolution. As an evaluation condition, a light / dark pattern of one line pair was projected at a pixel density on an XGA-compatible panel, and the light / dark contrast ratio (CTF value) of the image was evaluated. That is, when the white level is W and the black level is B, CTF = (W−B) / (W + B)
In the sandwiched sample (the optical element of the present embodiment), the CTF value indicated by is markedly improved to 80% or more. FIG. 5 shows the state of the wavefront aberration of the present embodiment corresponding to FIG. 19 described above, and it can be seen that it is remarkably improved.

  As described above, it was confirmed that the planarity was improved through the adhesive member (adhesive layer) of the glass substrate. That is, in the past, a polarizing plate or the like was pasted with an adhesive applied on a single glass substrate, but two sides of the polarizing plate (or wavelength plate) were passed through an adhesive layer. By adopting a configuration in which the glass substrate is sandwiched, improvement in projection performance can be achieved. Conventionally, in the case where a polarizing plate or the like is simply disposed between two glass substrates, aberration due to a change in refractive index is generated by forming a layer of air. However, the occurrence of aberration is suppressed through the adhesive layer in this way.

  FIG. 16 is a graph showing calculation results of wavefront aberration and resolution performance of an optical member arranged in the projection system. The calculation assumes a case where the wavefront aberration changes gently within the effective transmission area (approximately 40 mm square).

  The projected image is an XGA-compatible panel and is a value corresponding to a CTF value in which a light and dark pattern of one line pair is projected on the screen at a pixel density, and has 90% ability when there is no wavefront aberration. It can be seen that the level drops to 80% due to the occurrence of aberration of ± 2λ. Therefore, it is desirable to set the amount of wavefront aberration within 2λ as a level at which the resolution is not lowered by the structure sandwiched between the glass substrates. Although it depends on the specifications, the CTF is preferably about 50%. In this case, the wavefront aberration amount is preferably 5λ or less. The state of deterioration described above is a case where there is a single member to be arranged in the projection optical system. If a plurality of members are arranged, the aberration amounts are accumulated, which greatly affects the projection performance. Therefore, it is desirable to reduce the number of insertion members as much as possible.

  FIG. 6 is a diagram illustrating another example of the polarizing element and the phase modulation element of the present embodiment. As shown in FIG. 6, the polarizer 61 is sandwiched between the first glass substrate 63a and the second glass substrate 63b via the first adhesive layer 64a and the second adhesive layer 64b. Similarly, the wave plate 62 is sandwiched between the third glass substrate 63c and the fourth glass substrate 63d via the third adhesive layer 64c and the fourth adhesive layer 64d.

  Thus, in this embodiment, it comprises as a polarizing element and a phase modulation element which inserted | pinched the wavelength plate and the polarizer independently by the glass base material, and improves each plane. A feature of this configuration is that the wavelength plate is not affected by a temperature change due to heat absorption of the polarizer.

  At this time, in order to suppress the occurrence of aberration due to the change in the refractive index with air, the polarizing element and the phase modulation element are separated by a certain distance (not affected by the temperature change due to the heat absorption of the polarizer). It is preferable that they are arranged in close proximity.

In the present embodiment, as shown in FIG. 8, a polarizer 81 is interposed between the first glass substrate 83a and the second glass substrate 83b via an adhesive layer (first adhesive layer 84a and second adhesive layer 84b). The wave plate 82 may be sandwiched between the second glass substrate 83b and the third glass substrate 83c via the adhesive layers (the third adhesive layer 84c and the fourth adhesive layer 84d).
Further, the image forming engine of the present embodiment can have a configuration as shown in FIG. 8, that is, a configuration in which a polarizer and a wave plate are arranged on both sides via a single glass substrate. Such an image forming engine of the present embodiment is shown in FIG.

  With such a configuration, the number of glass substrates is reduced as compared with FIG. 6 described above, and the configuration of the optical elements (polarization element and phase modulation element) becomes compact. Therefore, the back focus of the projection lens can be shortened.

  Moreover, in this embodiment, as shown in FIG. 9, among a structure shown in FIG. 8 mentioned above, a polarizer and a wavelength plate are adjacently arranged only with an adhesive member without a glass substrate, and the outside is a glass substrate. It is also possible to adopt a configuration that sandwiches them.

In FIG. 9, the polarizer 91 and the wave plate 92 are in close contact (adhered) via the second adhesive layer 94b. Further, the first adhesive layer 94a and the third adhesive layer 94c are respectively bonded to the outside of the polarizer 91 and the wave plate 92 (on the opposite side of the adhesive surface to the second adhesive layer 94b), and the outside is further attached to the first glass. It is configured to be sandwiched between the base material 93a and the second glass base material 93b.
In the case of this configuration, the optical element can be made more compact, and the back focus of the projection lens can be further shortened.

In the present embodiment, a gold lattice polarizer can also be used. FIG. 10 shows the configuration.
In FIG. 10, the wave plate 102 is sandwiched between the first adhesive layer 104a and the second adhesive layer 104b, and the outside thereof is sandwiched between the first glass substrate 103a and the second glass substrate 103b. Further, a gold-line grating type polarizer 101 is provided on the base material surface outside the first glass base material 103a (side facing the first adhesive layer 104a).

The gold-line grating type polarizer is a so-called wire grid polarizer having a periodic pattern of metal having a wavelength size or less, and cannot be handled as it is, so that it is on a transparent glass substrate (here, the first glass substrate). 103a). A wave plate is disposed on the opposite side of the glass substrate on which the wire grid is formed. The wave plate is configured to be sandwiched between a glass substrate provided with a wire grid polarizer and another glass substrate via an adhesive layer.
With such a configuration, it is possible to provide an image forming engine in which polarization characteristics are remarkably improved and transmitted wavefront aberration is suppressed.

In the present embodiment, a dichroic prism can be used in place of the third glass substrate 83c in FIG. In this case, the dichroic prism is replaced with the third glass substrate 83c, and the wave plate 132 is sandwiched between the second glass substrate 133b and the dichroic prism 135 via the fourth adhesive layer 134d as shown in FIG. The structure is as follows. That is, the wave plate 132 and the polarizer 131 are attached to the dichroic prism 135 directly through the glass substrate.
An image forming engine having the polarization element and the phase modulation element shown in FIG. 13 is shown in FIG.

In FIG. 13, the wave plate 131 and the polarizing element are both attached to the dichroic prism via the glass substrate. However, as shown in FIG. 6, the glass between the polarizer and the wave plate is used. It is also possible to adopt a configuration in which the function as a polarizing element and the function as a phase modulation element are separated by separating the base materials (substituting the fourth glass base material 63d in FIG. 6 with a dichroic prism).
By adopting such a configuration, it is possible to easily exchange the polarizing element.

  Similarly, a configuration using a dichroic prism in place of the glass substrate (second glass substrate 93b in FIG. 9) described with reference to FIG. The configuration in this case is shown in FIG. Further, as shown in FIG. 14, the second glass substrate 103b in FIG. 10 may be replaced with a dichroic prism.

  FIG. 11 is a diagram showing an imaging engine when the polarizing element shown in FIG. 4 and a wave plate are sandwiched between a dichroic prism and a glass substrate. In the case of FIG. 11, a configuration is adopted in which a polarizing element 113 sandwiching a polarizer and a half-wave plate are sandwiched between a dichroic prism 116 and a glass substrate 114. In this way, the optical element can be made compact. Further, by separating the wave plate having a phase modulation function and the polarizer having heat absorption, the wave plate is not affected by the temperature change of the polarizer.

  FIG. 16 is a diagram showing an image forming engine having the polarization element and the phase modulation element shown in FIG.

  The image forming engine of this embodiment includes three light valves 161R, 161G, and 161B corresponding to three colors of red (R), green (G), and blue (B), and panel-modulated light corresponding to each color. An optical path separating element (PBS: polarization beam splitter) 162 for extracting only the light, and a color synthesizing element (dichroic prism) 165 for synthesizing images formed by light valves (161R, 161G, 161B) corresponding to R, G, B It is an imaging engine equipped with.

  The light valves 161R, 161G, and 161B can be applied to any spatial modulation element that controls polarization, such as a transmissive liquid crystal panel or a reflective liquid crystal panel. FIG. 16 shows a case where a reflective liquid crystal panel is mounted. The light valve controls the polarization according to the image signal, and an image is formed through an optical path separation element such as a polarization beam splitter.

  Image modulated light from the red light valve 161R and the blue light valve 161B passes through the glass substrate, polarizer, half-wave plate, and dichroic prism in this order by PBSs 162R and 162B corresponding to the respective colors. To do. Here, the glass substrate 1, the polarizer, and the half-wave plate are closely arranged via an adhesive layer (adhesive member), so that the transmitted wavefront aberration can be reduced, and the influence on the projection performance can be reduced. It is possible to suppress as much as possible, and it is possible to cope with higher resolution.

  As the adhesive used for the adhesive layer (adhesive member) of this embodiment described above, a UV adhesive is generally used. However, the purpose of the adhesive layer in the present embodiment is to eliminate the air layer that exists between the glass substrate and each substrate such as a polarizer and a wave plate, thereby aberration associated with a change in refractive index with air. It is to suppress the occurrence. Therefore, the adhesive has a function as a buffer layer interposed between a glass substrate, a polarizer, a wave plate and the like, and is not limited to a UV adhesive as long as it is a material having such a function. As described above, in the embodiment of the present invention, by interposing the adhesive layer, it is possible to suppress the occurrence of aberrations and improve the optical performance.

  In this embodiment, the panel image modulation light passes through the polarizer and the wave plate in this order. This is a case where priority is given to the contrast performance of the image. Is not limited to this order. Moreover, in order to ensure contrast performance, it is good also as a structure which inserts multiple polarizers.

  Furthermore, the image forming engine of this embodiment can be applied to a projection apparatus such as a projection projection apparatus. This is composed of the image forming engine of the present embodiment, an illumination optical system, and a projection lens that magnifies and projects an image of a light valve.

  The illumination optical system is an illumination optical system in which white light such as a high-pressure mercury lamp or a xenon lamp is color-separated corresponding to each color of R, G, and B using a dichroic mirror or the like. Illumination light is used in which non-polarized light is efficiently linearly polarized by a polarization conversion element composed of PBS and a wavelength plate.

  The projection lens enlarges and projects an image modulated from a liquid crystal panel called a micro display to form an image on the screen. The parallelism, flatness, wavefront aberration, etc. of the optical components inserted in the image forming system for enlarged projection greatly affect the quality of the projected image, but high resolution is achieved by using the image forming engine of this embodiment. Can be obtained. Furthermore, in the future, the pixel pitch is reduced, and it can be applied to higher definition display.

  As described above, according to the image forming engine of the present embodiment, the amount of transmitted wavefront aberration of the optical element disposed between the panel and the projected image can be reduced, so that the quality of the projected image can be maintained and high definition can be achieved. An image can be displayed.

  Further, by adopting a configuration in which the polarizing element and the polarization modulating element are separated from each other, the polarizing plate can be easily repaired even when the polarizing plate is deformed by heat.

  In addition, since the number of interfaces can be reduced as the number of glass substrates is reduced, the contrast is improved. In particular, when the polarizer and the wave plate are sandwiched between only two glass substrates and the adhesive layer, the glass substrate can be further reduced and the back focus can be shortened. Further, the degree of freedom in designing the projection lens is improved, and a compact projection engine can be realized.

  In addition, by using a gold lattice polarizer, the polarization characteristics are further improved and the heat resistance is also improved.

  In addition, among the configurations of the glass substrate that sandwiches the polarizer and the wave plate, by including a dichroic prism, the polarization element, the polarization element, or These composite elements can be realized. Further, the back focus of the projection lens can be shortened, and the performance of the projection lens can be improved and the cost can be reduced.

  Furthermore, according to the projection apparatus of the present embodiment, since the polarizing element and the phase modulation element having the glass sand structure are mounted, it is possible to perform the projection with the wavefront aberration amount minimized and the degradation of the resolution performance suppressed. In addition, it is possible to reduce the impossibility of the projection lens while improving the resolution performance, and to achieve downsizing and cost reduction of the apparatus. In addition, since the back focus of the lens can be shortened, the entire apparatus can be made compact at the same time.

It is a figure which shows the image formation engine using the reflection type panel of this embodiment, (a) shows a top view, (b) shows the figure from the projection lens side. It is a figure which shows the image formation engine using the transmissive | pervious panel of this embodiment. It is a figure which shows the image formation engine at the time of using a gold | metal wire grid type | mold PBS and a reflection type panel. It is a figure which shows typically the polarizing element of this embodiment. It is a figure which shows wavefront aberration evaluation by the image formation engine of this embodiment. It is a figure which shows an example of the optical element of this embodiment. It is a figure which shows the image formation engine at the time of using the optical element shown in FIG. It is a figure which shows another example of the optical element of this embodiment. It is a figure which shows another example of the optical element of this embodiment. It is a figure which shows the optical element at the time of using a wire grid type polarizer. It is a figure which shows the image formation engine at the time of pinching | interposing a wavelength plate with a glass base material and a dichroic prism. It is a figure which shows the image formation engine at the time of using the optical element shown in FIG. It is a figure which shows another example of the optical element of this embodiment. It is a figure which shows an optical element at the time of pinching | interposing a wavelength plate with the glass base material which has a wire grid type polarizer, and a dichroic prism. It is a figure which shows an optical element at the time of pinching a polarizer and a wavelength plate with a glass base material and a dichroic prism. It is the graph which showed the calculation result of the wavefront aberration and the resolution performance of the optical member arrange | positioned in a projection system. It is a figure which shows the conventional image forming engine typically. It is a figure which shows wavefront aberration evaluation by the conventional image forming engine. It is a figure which shows an example of the conventional polarizing element.

Explanation of symbols

11R, 11G, 11B Light valve 12R, 12G, 12B PBS (polarization beam splitter)
13R, 13G, 13B Polarizing element 14R, 14G, 14B Phase modulation element 15 Dichroic prism 16R, 16B Color reflection film 17 Projection lens

Claims (11)

A light source that emits light of a plurality of colors, a light valve that modulates light by transmitting or reflecting incident light from the light source, and a polarizer or a wave plate provided on an optical path of light emitted from the light valve An imaging engine having an optical element,
An image forming engine, wherein at least one of the polarizer and the wave plate constituting the optical element is sandwiched between glass substrates through an adhesive layer. The optical element is
A polarizing element in which both sides of the polarizer are sandwiched between the first glass substrate and the second glass substrate via the adhesive layer;
The imaging engine according to claim 1, wherein both sides of the wave plate have a phase modulation element sandwiched between a third glass substrate and a fourth glass substrate via the adhesive layer. . The optical element is
Both sides of the polarizer are sandwiched between the first glass substrate and the second glass substrate via the adhesive layer, and both sides of the wave plate are interposed between the second and second glass substrates. 2. The image forming engine according to claim 1, wherein the image forming engine is sandwiched between a glass substrate and a third glass substrate. The optical element is
The first glass substrate and the second glass substrate, which are disposed adjacent to each other with the adhesive layer interposed between the polarizer and the surface on the side adjacent to each other. The image forming engine according to claim 1, wherein the image forming engine is sandwiched between glass substrates. The polarizer is composed of a metal pattern having a pitch equal to or less than the wavelength of the emitted light,
The optical element is
A first glass substrate disposed on both sides of the wave plate on the light valve side via the adhesive layer, and a second glass plate disposed symmetrically via the first glass substrate and the wave plate 2. The structure according to claim 1, further comprising a polarizer sandwiched between a glass substrate and having the metal pattern on the light valve side surface of the first glass substrate. Statue engine. A light source that emits light of a plurality of colors, a light valve for each of the plurality of colors that is provided corresponding to each color light from the light source and transmits or reflects incident light of each color, and each color from the light valve An image forming engine having a color synthesizing element that synthesizes light emitted from light and an optical element that is provided on an optical path between the light valve and the color synthesizing element and includes a polarizer and a wave plate. And
The optical element is
A polarizing element in which both sides of the polarizer are sandwiched between glass substrates via an adhesive layer;
An image forming engine, wherein the wavelength plate includes a glass substrate and a phase modulation element sandwiched between the color synthesis elements via an adhesive layer. The optical element is
A polarizing element in which both sides of the polarizer are sandwiched between the first glass substrate and the second glass substrate via the adhesive layer;
The image forming engine according to claim 6, wherein both sides of the wave plate have a phase modulation element sandwiched between the third glass substrate and the color synthesizing element via the adhesive layer. The optical element is
Both sides of the polarizer are sandwiched between the first glass substrate and the second glass substrate via the adhesive layer, and both sides of the wave plate are interposed between the second and second glass substrates. The image forming engine according to claim 6, wherein the image forming engine is sandwiched between a glass substrate and the color composition element. The optical element is
The polarizer and the wave plate are disposed adjacent to each other via the adhesive layer, and the glass substrate and the color synthesizing element are provided on the opposite surface to the surface disposed adjacent to each other via the adhesive layer. The image forming engine according to claim 6, wherein the image forming engine is sandwiched between the two. The polarizer is composed of a metal pattern having a pitch equal to or less than the wavelength of the emitted light,
The optical element is
A first glass substrate disposed on both sides of the wave plate on the light valve side via the adhesive layer, and the color composition disposed symmetrically via the first glass substrate and the wave plate 2. The imaging engine according to claim 1, further comprising a polarizer sandwiched between the elements and having the metal pattern on a surface of the first glass substrate on the light valve side. .   11. A projection apparatus comprising: the image forming engine according to claim 1; an illumination optical system; and a projection optical system for enlarging and projecting an image formed by the image forming engine. .

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