JP2003280093A - Rear projector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a compact rear projector having little luminance irregularity even when making the thickness of the projector in a depth direction and that in a height direction much smaller by shortening a projection distance. <P>SOLUTION: A gradient film 21 for correcting the luminance irregularity is formed on a reflection mirror 20. When image light being P polarized light is made incident on the mirror 20, for example, the film 21 acts on the image light so that the upside of a screen 30 may be bright and the downside thereof may be dark, and such characteristic that the upside of the screen 30 becomes dark and the downside thereof becomes bright is cancelled by incident angle dependency. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rear projector, and more particularly to a projection optical system for generating and emitting image light, a reflection mirror for reflecting the image light emitted by the projection optical system, and A rear projector having a screen that displays the image by entering the image light reflected by a reflection mirror from one end face side and emitting the image light from the other end face side, and particularly, a rear projector having a projection image on the screen generated by thinning. The present invention relates to a technique for suppressing uneven brightness.

[0002]

2. Description of the Related Art Generally, a rear projector includes a projection optical system for generating and emitting image light, and the image light emitted by the projection optical system from one end face side and the other end face side. And a screen for displaying an image, and the projection optical system is incorporated in a housing in which the screen is fitted on the front side to form an integrated structure.

In such a conventional rear projector, the projection optical system is shifted in the height direction and built in the lower side of the housing, and the image light emitted upward by the projection optical system is reflected on the screen. It is known that a reflecting mirror that is guided by the housing is arranged, the projection distance in the depth direction is shortened, and the thickness of the housing in the depth direction is thinned.

According to Fresnel's law of reflection, the reflection mirror has a higher reflectance for light oscillating in a direction orthogonal to an incident surface on which image light is incident than a reflectance for light oscillating in a direction parallel to the incident surface. Have the following characteristics. Similarly, the screen has a characteristic that the transmittance of light oscillating in the direction orthogonal to the incident surface on which image light is incident is lower than the transmittance of light oscillating in the direction parallel to the incident surface.

[0005]

In the conventional rear projector described above, the projection distance is shortened in order to reduce the size of the device by further reducing the thickness in the depth direction and the thickness in the height direction. Is also an effective method.

However, in the conventional rear projector, when the projection distance is simply shortened, the image light becomes wide angle and the inclination angle of the reflection mirror becomes shallow, so that the incident angle to the reflection mirror becomes larger depending on the incident position. Differently, the incident angle dependence of the reflectance of the reflecting mirror becomes remarkable, and the reflectance of the reflecting mirror on the side on which the incident angle of the image light projected from the projection optical system is large and the surface on the side on which the incident angle is small are small. There is a problem that the reflectance is different from that and uneven brightness occurs on the screen displayed on the screen.

Further, in the conventional rear projector, when the projection distance is simply shortened, the incident angle to the screen also largely varies depending on the incident position, so that the incident angle dependency of the transmittance of the screen becomes remarkable, There is a problem that uneven brightness occurs on the screen displayed on the screen.

In particular, since the reflection mirror and the screen also have the above-mentioned polarization dependency, when the polarization state is different for each color, the uneven brightness on the screen is different for each color.
There is a problem that remarkable color unevenness occurs.

Therefore, the present invention has been made in view of the above, and has a small projection distance and a small luminance unevenness even when the thickness in the depth direction and the thickness in the height direction are further reduced. The purpose is to provide a rear projector.

[0010]

In order to achieve the above-mentioned object, a rear projector according to the present invention comprises a projection optical system for generating and emitting image light and a reflection of the image light emitted by the projection optical system. In a rear projector having a reflection mirror for displaying an image by entering the image light reflected by the reflection mirror from one end face side and emitting the image light from the other end face side, the reflection mirror is reflected. It is characterized by further comprising a brightness uniformization correction means for correcting the brightness of the image light so that the brightness of the image light is substantially uniform when the light is emitted from the screen.

Accordingly, the brightness uniformity correction means corrects the brightness of the image light reflected by the reflection mirror so that the brightness of the image light is substantially uniform when the image light is emitted from the screen, so that the image projected from the projection optical system. It is possible to cancel the incident angle dependency that the reflectance of the reflecting mirror on the surface on the side of large incident angle of light is different from the reflectance of the surface on the side of small incident angle.

Therefore, according to the rear projector of the present invention, even if the image light is widened and the inclination angle of the reflection mirror is made shallow to shorten the projection distance from the projection optical system to the screen, It is possible to suppress the influence of the incident angle dependence of the reflectance. Therefore, according to the present invention, it is possible to provide a small rear projector with less unevenness in brightness even when the projection distance is shortened and the thickness in the depth direction and the thickness in the height direction are further reduced.

As will be described below, for example, the above-described brightness uniformizing correction means having a characteristic opposite to the incident angle dependency of the reflectance of the reflection mirror is provided in the reflection mirror, the projection optical system or the screen. With the provision, both characteristics are canceled out, the influence of the incident angle dependency is reduced, and the uneven brightness on the screen can be reduced.

For example, in the brightness uniformity correction means, the reflectance of the surface on the side of a large incident angle and the reflectance of the surface on the side of a small incident angle of the image light projected from the projection optical system are respectively incident. The reflection mirror may be formed so as to have substantially the same angle. Specifically, it is preferable that an inclined film is formed on the surface of the reflection mirror on which the image light projected from the projection optical system is incident. In this case, the reflectance of the surface on the side where the incident angle of the image light projected from the projection optical system is large and the reflectance of the surface on the side where the incident angle is small are substantially the same at the respective incident angles. It is preferable that the gradient film is formed so that the film thickness is partially different.

According to this structure, in the reflection mirror, the reflectance of the surface on the side where the incident angle of the image light projected from the projection optical system is large and the reflectance of the surface on the side where the incident angle is small are respectively. Since they are formed so as to have substantially the same incident angle of, the brightness of the image light after the image light projected from the projection optical system is reflected by the reflection mirror is almost the same when the image light is emitted from the screen. It can be corrected to be uniform.

Further, the brightness uniformization correction means may be the projection optical system which emits image light in which the brightness of the image light reflected by the reflection mirror is corrected to be substantially uniform when the image light is emitted from the screen. .

According to this structure, the projection optical system emits the image light in which the brightness of the image light reflected by the reflection mirror is corrected to be substantially uniform when the image light is emitted from the screen. The brightness of the image light after the image light projected from the projection optical system is reflected by the reflection mirror can be corrected so as to be substantially uniform when the image light is emitted from the screen.

Further, the brightness uniformization correction means may be a screen having a transmittance that corrects and transmits the image light reflected by the reflection mirror and incident so that the brightness thereof is substantially uniform at the time of emission.

According to this structure, the screen has a transmittance that is corrected and transmitted so that the brightness of the image light reflected by the reflection mirror and incident on the screen is substantially uniform at the time of emission. It is possible to correct the brightness of the image light after the image light projected from is reflected by the reflection mirror so as to be substantially uniform when the image light is emitted from the screen.

Further, a projection optical system for generating and emitting image light, a reflection mirror for reflecting the image light emitted by the projection optical system, and the image light reflected by the reflection mirror from one end face side. In a rear projector having a screen which is incident and emerges from the other end face side to display an image, the screen has a light guide section which corrects and guides an incident angle of the image light with respect to the screen. It is characterized by being prepared on the side.

According to this structure, the screen is provided with a light guide section for correcting and guiding the incident angle of the image light with respect to the screen on the incident end face side, and the image light is guided to the light guide section at a small incident angle. Since the image light is made incident and guided to the screen, the influence of the incident angle dependence of the transmittance of the screen is reduced. Therefore, according to the present invention, it is possible to provide a small rear projector with less unevenness in brightness even when the projection distance is shortened and the thickness in the depth direction and the thickness in the height direction are further reduced.

It is preferable that the light guide section has a condensing characteristic together with the Fresnel lens forming the incident end surface side of the screen. According to this light guide section, the incident angle of the image light reflected from the reflection mirror can be made small, and the uneven brightness due to the incident angle dependency on the screen can be suppressed, and the light condensing function of the Fresnel lens can be achieved. Can reduce the angle of incidence on the screen without affecting,
The light condensing function of the Fresnel lens can be assisted.

Further, the light guide section may be integrally formed with a Fresnel lens which constitutes the screen, and the light guide section and the Fresnel lens may constitute a meniscus lens. According to this light guide portion, a meniscus lens is configured with a Fresnel lens, so that the incident angle of the image light reflected from the reflection mirror can be reduced, and the uneven brightness due to the incident angle dependency on the screen can be suppressed. In addition, the design of both the light guiding function and the light collecting function can be facilitated.

Further, the light guide portion may have a prism shape arranged in accordance with the concentric circle shape of the Fresnel lens. According to this light guide portion, since it has a prism shape, it is possible to reduce the incident angle of the image light reflected from the reflection mirror and suppress the uneven brightness due to the incident angle dependency on the screen.

Further, the light guide portion may be formed only in the peripheral portion of the screen. According to this light guide section, it is possible to reduce the incident angle of the peripheral portion where the incident angle of the image light reflected from the reflection mirror is large.

Furthermore, it is preferable that the projection optical system emits image light of at least two colors having the same polarization state. According to this configuration, the polarization state of each color of the image light emitted from the projection optical system is made uniform, so that it is possible to prevent uneven brightness and uneven color due to the incident angle dependency due to the difference in the polarized state.

The polarization state may be aligned with P-polarized light or S-polarized light with respect to the reflecting mirror. In either case, the characteristics of the brightness uniformity correction means may be set based on the incident angle dependence of each polarized light.

Further, the projection optical system has a light source and an integrator for converting the light emitted from the light source into a light having a substantially uniform illuminance distribution, and the projection optical system is provided in the optical path between the integrator and the screen. Brightness uniformity correction means may be provided. With this configuration, even if the image light is widened and the inclination angle of the reflection mirror is made shallow so that the projection distance between the projection optical system and the screen is shortened, the reflectance of the reflection mirror depends on the incident angle. A rear projector with reduced influence can be easily designed.

[0029]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described below in detail with reference to the drawings. The present invention is not limited to this embodiment.

(Embodiment 1) FIG. 1 is a diagram illustrating a schematic configuration of a rear projector of the present invention. The rear projector 100 includes a projection optical system 10 for generating and emitting image light, a reflection mirror 20 for reflecting the image light emitted by the projection optical system 10, and the image light reflected by the reflection mirror 20. An optical system mainly having a screen 30 that enters from one end face side and exits from the other end face side to display an image is built in a housing 40. The screen 30 is vertically fitted on the front surface side of the housing 40.

The projection optical system 10 has a light source device (not shown), an image forming optical system, a projection lens, etc., and generates and emits image light. The image light is emitted toward the reflection mirror 20 while spreading around the axis X, reflected by the reflection mirror 20, and projected on the screen 30. On the screen 30, the projected image light is transmitted and an image is displayed so that it can be visually recognized from the front side.

FIG. 2 is a diagram for explaining the main configuration of the rear projector according to the first embodiment of the present invention. In this rear projector 100, the image light projected by the projection optical system 10 enters the reflection mirror 20. As shown in the figure, the image light incident on the reflection mirror 20 is incident at an incident angle α on the upper side of the reflection mirror 20, and is incident at an incident angle β on the lower side thereof. Here, α> β.

At this time, when the image light projected by the projection optical system 10 is P-polarized with respect to the incident surface of the reflecting mirror (the surface parallel to the paper surface of the figure), the incident angle dependence based on Fresnel's law of reflection is used. Depending on the sex, in the conventional case, the screen 30
The brightness unevenness occurred such that the upper side of the image was dark and the lower side was bright.

However, the reflecting mirror 20 is formed with an inclined film 21 for correcting the uneven brightness. The inclined film 21 acts on the image light so that the upper side of the screen 30 is bright and the lower side is dark, and the upper side of the screen 30 is dark and the lower side is bright due to the incident angle dependency. Will be offset.

FIG. 3 is a diagram showing the concept of the reflection mirror of the rear projector according to the first embodiment of the present invention. In this reflection mirror 20, the upper side is formed with a film thinner than the lower side so that the upper side has a higher reflectance. By thus increasing the reflectance on the upper side, the image light incident on the upper side of the reflection mirror 20 is more easily reflected than the image light incident on the lower side. Therefore, the reflection mirror 20
Will correct the brightness of the reflected image light so that it becomes uniform when it exits the screen 30.

(Modification 1) FIG. 4 is a diagram showing the concept of a modification of the reflection mirror of the rear projector according to Embodiment 1 of the present invention. In this reflection mirror 20, a film is made thinner on the lower side than on the upper side so that the reflectance on the lower side is higher. If the reflectance of the lower side is increased like this,
The image light incident on the lower side of the reflection mirror 20 is more easily reflected than the image light incident on the upper side thereof. Therefore,
When the S-polarized light is incident on the incident surface of the reflection mirror, the reflection mirror 20 changes the brightness of the reflected image light by
It is corrected so as to be uniform when ejected from the screen 30.

The inclined film 21 or 22 can be formed by changing the film thickness above and below by arranging the reflecting mirror 20 so as to be inclined with respect to the film component emission port when the film is deposited on the reflecting mirror 20. Can be manufactured.

According to the first embodiment, the reflection mirror 20 has the reflectance of the surface on the side where the incident angle of the image light projected from the projection optical system 10 is large and the surface of the side on which the incident angle is small. Since the inclined film 21 or 22 is formed so that the reflectance is the same at each incident angle, the image light projected from the projection optical system 10 is reflected by the reflection mirror 2.
The brightness of the image light after being reflected at 0 is set to the screen 3
It can be corrected to be uniform at the time of injection from 0. That is, the reflection mirror 20 on which the inclined film 21 or 22 is formed functions as a brightness uniformity correction means.

The structure of the gradient film 21 or 22 is not limited to this. That is, the directions of change in the film thickness may be opposite to each other as long as they have a characteristic of canceling the incident angle dependency of the reflection mirror. Further, in the above-described first embodiment, the tilt film is described as an example in which the film thickness is continuously changed linearly from the upper side to the lower side of the reflection mirror 20. The film may be formed such that the film thickness is changed stepwise from the upper side to the lower side of the reflection mirror 20.

Further, in the first embodiment, the example of the inclined film in the case where the reflecting surface of the reflecting mirror 20 is a flat surface has been described, but the reflecting surface of the reflecting mirror may be a curved surface such as a spherical surface or an aspherical surface. The present invention can be applied. Also in this case, the inclined film may be formed so that the reflectance is the same at each incident angle according to the incident angle of the image light projected from the projection optical system and incident on the reflection surface of the reflection mirror.

Further, in the above-mentioned embodiment, the case where the reflection characteristic is changed only in the vertical direction of the reflecting mirror has been described, but it is also possible to change it in the direction orthogonal to this.
This is effective in further reducing the influence of the incident angle dependency of the reflecting mirror. Furthermore, although the case where the number of films is one has been described, a multilayer film may be used.

(Second Embodiment) FIG. 5 is a diagram for explaining a main configuration of a rear projector according to a second embodiment of the present invention. In the first embodiment, the reflection mirror 20 is provided with means for correcting the uneven brightness of the image displayed on the screen 30, whereas in the second embodiment, the brightness is made uniform on the screen 30. The difference is that a means for correcting the uneven brightness of the image is provided. The same components as those in the first embodiment will be designated by the same reference numerals and the description thereof will be omitted.

The screen 30 is provided with a brightness uniformity correction means 31. This brightness uniformity correction means 31
Has a transmittance that is corrected and transmitted so that the brightness of the image light reflected by the reflection mirror 20 and incident is uniform at the time of emission.

For example, when the image light projected by the projection optical system 10 is P-polarized with respect to the incident surface of the reflection mirror 20,
By the incident angle dependence based on Fresnel's law of reflection,
Image light that makes the upper side of the screen 30 dark and the lower side of the screen 30 incident on the screen 30 causes the screen 30 to be dark.
Has a transmittance that allows image light to be transmitted such that the upper side is bright and the lower side is dark.

FIG. 6 is a diagram showing the concept of a lens group which constitutes the screen of the rear projector according to the second embodiment of the present invention. The screen 30 has an inclined film 31a as the brightness uniformization correction means 31, a Fresnel lens 32 integrally formed with the inclined film 31a, and a main screen 33.

The inclined film 31a is formed by the Fresnel lens 32.
Is a film that is formed on the incident end face side of as a brightness uniformizing correction means. The gradient film 31a may be manufactured in the same manner as the gradient film 21 described in the first embodiment. The Fresnel lens 32 realizes a condensing function. The main screen 33 is formed of a lenticular lens and a diffusion layer.

(Modification 2) When the image light projected by the projection optical system 10 is S-polarized with respect to the incident surface of the reflection mirror, the incident angle dependence based on Fresnel's law of reflection causes the screen 30 to change. Since image light whose upper side is bright and whose lower side is dark is incident on the screen 30, it is sufficient to have a transmittance for transmitting image light so that the upper side of the screen 30 is dark and its lower side is bright. Further, the transmittance may be changed by changing the density of fine particles instead of the gradient film 31a. In this case, the density of the fine particles having a higher transmittance may be reduced.

The structure of the screen 30 for suppressing the uneven brightness due to the incident angle dependency on the screen 30 will be described below. In addition, in combination with the case of suppressing the brightness unevenness based on the incident angle dependency of the reflection mirror 20 described above,
It is possible to display an image with little brightness unevenness on the screen 30.

FIG. 7 shows another example 1 of the lens group constituting the screen of the rear projector according to the second embodiment of the present invention.
It is a figure which shows the concept of. The screen 30 includes a Fresnel lens 34 having a curved surface 31b as a light guide section,
It has a main screen 33.

Since the Fresnel lens 34 has the curved surface 31b having a condensing function, it has a function as a meniscus lens. The curvature of the curved surface 31b may be determined according to the spread angle of the image light incident from the reflection mirror 20. In addition, the curved surface 31
A Fresnel structure in which b is divided stepwise and rearranged on a plane may be used. Alternatively, only the peripheral portion of the Fresnel lens 34 may have a curved surface, and the central portion may be a flat surface. In this case, a region having a large incident angle of the image light incident from the reflection mirror 20 can have a small incident angle.

On the curved surface 31b, since the angle with respect to the normal line is the incident angle, the incident angle can be made smaller than that of a flat surface. Therefore, the property based on the incident angle dependency, which becomes remarkable as the incident angle of the image light incident on the screen 30 increases, can be suppressed by reducing the incident angle.

FIG. 8 shows another example 2 of the lens groups constituting the screen of the rear projector according to the second embodiment of the present invention.
It is a figure which shows the concept of. FIG. 9 is a plan view illustrating the Fresnel lens of the screen shown in FIG. Figure 8
In the above, the screen 30 has a Fresnel lens 35 having a prism 31c as a light guide portion, and a main screen 33. The prism 31c is
As shown in FIG. 9, it is formed concentrically on the incident end face side of the Fresnel lens 35 so as to match the concentric shape of the Fresnel lens 35.

The prism 31c has an inclined surface corresponding to the spread angle of the image light incident from the reflection mirror 20. Since the incident angle of the image light from the reflection mirror 20 is an angle with respect to the normal line of the inclined surface, it is possible to suppress the incident angle dependency, which becomes remarkable as the incident angle increases.

FIG. 10 is a diagram showing the concept of another example 3 of the lens groups constituting the screen of the rear projector according to the second embodiment of the present invention. The screen 30 has a Fresnel lens 36 in which a prism 31d as a light guide is formed around the incident end face, and a main screen 33. The prism 31d is concentrically formed around the incident end surface of the Fresnel lens 35 so as to match the concentric shape of the Fresnel lens 35, as in the case described with reference to FIG.

The prism 31d has an inclined surface corresponding to the spread angle of the image light incident from the reflection mirror 20. The incident angle of the image light from the reflection mirror 20 is an angle with respect to the normal line of the inclined surface, and it is possible to suppress the incident angle dependency, which becomes remarkable as the incident angle increases. In particular, since the incident angle becomes large in the peripheral portion of the incident end surface of the Fresnel lens 35, the incident angle at that portion can be made small.

According to the second embodiment, the screen 3
Since the brightness uniformity correction means 31 provided at 0 adjusts the brightness according to the transmittance of the image light, the brightness of the image light reflected by the reflection mirror 20 and incident is corrected to be uniform at the time of emission. be able to. Further, by providing the light guide portion that guides the image light from the reflection mirror to the Fresnel lens 35 at a small incident angle, it is possible to suppress the uneven brightness due to the incident angle dependency of the screen.

(Third Embodiment) FIG. 11 is a diagram for explaining a schematic configuration of a rear projector according to a third embodiment of the present invention. In the rear projector 100 described in the first embodiment, it is assumed that the image light emitted from the projection optical system 10 is directly emitted from the projection lens (not shown) to the reflection mirror 20. On the other hand, the third embodiment
The rear projector 200 is different in that the projection optical system 50 is incorporated in place of the projection optical system 10 and a brightness equalizing correction means is provided on the projection optical system 50 side.

In the projection optical system 50, a folding mirror 51 is arranged in the optical path between a projection lens (not shown) and the reflection mirror 20. The tilted film formed on the surface of the reflection mirror 20 described in the first embodiment is formed on the surface of the folding mirror 51 to suppress the uneven brightness due to the incident angle dependency of the reflection mirror 20. is there. In this case, it is necessary to design so as to suppress uneven brightness due to the incident angle dependency of the folding mirror 51 itself.

(Modification 3) In the projection optical system 50,
Not only the folding mirror 51, but also any portion in the optical path in the latter stage of the integrator (not shown) may be provided with the brightness uniformization correction means. The brightness uniformization correction means here is not only the above-mentioned optical means, but also electrically corrects the characteristics of an electro-optical element (for example, a liquid crystal panel) that forms a projected image in the projection optical system. Including things.
Here, the reason behind the integrator is that in the integrator, since the light is once subdivided and then superimposed,
This is because the brightness cannot be adjusted so as to suppress uneven brightness during that time.

In the third embodiment, since the projection optical system 50 is provided with the brightness uniformization correction means, the same effect as that of the first embodiment can be obtained.

In the first or second embodiment, the brightness uniformity correction means is provided between the projection optical system and the screen, and in the third embodiment, the brightness uniformity correction means is provided downstream of the integrator. Explained. Therefore, the above-described first to third embodiments may be combined to provide the brightness uniformity correction means at each position. In addition, the brightness uniformization correction means is provided in the optical path from the projection optical system to the screen (including the screen) in the subsequent stage,
It may be provided at any place.

[0062]

As described above, according to the rear projector of the present invention, the image light is widened and the inclination angle of the reflection mirror is made shallow to shorten the projection distance from the projection optical system to the screen. However, the influence of the incident angle dependency of the reflectance of the reflection mirror can be reduced. Further, the influence of the incident angle dependency of the transmittance of the screen can be reduced. Therefore,
According to the present invention, it is possible to provide a small rear projector with less unevenness in brightness even when the projection distance is shortened and the thickness in the depth direction and the thickness in the height direction are further reduced.

[Brief description of drawings]

FIG. 1 is a diagram illustrating a schematic configuration of a rear projector of the present invention.

FIG. 2 is a diagram illustrating a main configuration of the rear projector according to the first embodiment of the present invention.

FIG. 3 is a diagram showing a concept of a reflection mirror of the rear projector according to the first embodiment of the present invention.

FIG. 4 is a diagram showing a concept of a modification of the reflection mirror of the rear projector according to the first embodiment of the present invention.

FIG. 5 is a diagram illustrating a main configuration of a rear projector according to a second embodiment of the present invention.

FIG. 6 is a diagram showing a concept of a lens group forming a screen of a rear projector according to a second embodiment of the present invention.

FIG. 7 is a diagram showing the concept of another example 1 of the lens groups forming the screen of the rear projector according to the second embodiment of the present invention.

FIG. 8 is a diagram showing the concept of another example 2 of the lens groups forming the screen of the rear projector according to the second embodiment of the present invention.

9 is a plan view illustrating a Fresnel lens of the screen shown in FIG.

FIG. 10 is a diagram showing the concept of another example 3 of the lens groups forming the screen of the rear projector according to the second embodiment of the present invention.

FIG. 11 is a diagram illustrating a schematic configuration of a rear projector according to a third embodiment of the present invention.

[Explanation of symbols]

10 Projection optical system 20 reflective mirror 21 inclined membrane 30 screen 31 Brightness uniformity correction means 31a inclined film 31b curved surface 31c prism 31d prism 32 Fresnel lens 33 Main screen 34 Fresnel lens 35 Fresnel lens 36 Fresnel lens 40 cases 50 Projection optical system 51 mirror 100 rear projector 200 rear projector X axis α incident angle β incident angle

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) G02B 27/18 G02B 27/18 Z 27/28 27/28 Z G03B 21/60 G03B 21/60 ZF term (Reference) 2H021 BA22 BA28 2H042 DA01 DB00 DC02 DE00 2H052 BA01 BA02 BA09 BA14 2H099 AA12 BA09 CA11 DA09 2K103 AA17 AB05 AB07 BC03 BC23 BC38 CA01 CA20

Claims (15)

[Claims] 1. A projection optical system that generates and emits image light, a reflection mirror that reflects the image light emitted by the projection optical system, and the image light reflected by the reflection mirror from one end face side. In a rear projector having a screen which is incident and is emitted from the other end face side to display an image, the brightness of the image light reflected by the reflection mirror is corrected so as to be substantially uniform when the image light is emitted from the screen. A rear projector having a brightness uniformizing correction means. 2. The brightness uniformity correction means is configured such that the reflectance of the surface of the image light projected from the projection optical system on the side of a large incident angle and the reflectance of the surface on the side of a small incident angle are respectively incident. The rear projector according to claim 1, wherein the reflection mirrors are formed to have substantially the same corners. 3. The rear projector according to claim 2, wherein an inclined film is formed on a surface of the reflection mirror on which the image light projected from the projection optical system is incident. 4. The tilted film has a reflectance of a surface on the side of a large incident angle of image light projected from the projection optical system and a reflectance of a surface on the side of a small incident angle of the image light at respective incident angles. The rear projector according to claim 3, wherein the rear projectors are formed so as to have the same film thickness and are partially different in thickness. 5. The projection optical system, wherein the brightness uniformization correction means emits image light in which the brightness of the image light reflected by the reflection mirror is corrected to be substantially uniform when the image light is emitted from the screen. The rear projector according to claim 1, wherein: 6. The brightness uniformization correction means is a screen having a transmittance that corrects and transmits the image light reflected by the reflection mirror and incident so that the brightness of the image light is substantially uniform at the time of emission. The rear projector according to claim 1. 7. A projection optical system that generates and emits image light, a reflection mirror that reflects the image light emitted by the projection optical system, and the image light reflected by the reflection mirror from one end face side. In a rear projector having a screen which is incident and emerges from the other end face side to display an image, the screen has a light guide section which corrects and guides an incident angle of the image light with respect to the screen. A rear projector that is equipped on the side. 8. The rear projector according to claim 7, wherein the light guide section has a condensing characteristic together with a Fresnel lens forming an incident end surface side of the screen. 9. The light guide unit is integrally molded with a Fresnel lens that forms the screen, and the light guide unit and the Fresnel lens form a meniscus lens. Rear projector. 10. The rear projector according to claim 7, wherein the light guide portion has a prism shape arranged in accordance with a concentric circle shape of a Fresnel lens. 11. The rear projector as claimed in claim 7, wherein the light guide portion is formed only on a peripheral portion of the screen. 12. The rear projector according to claim 1, wherein the projection optical system emits image light of at least two colors having a uniform polarization state. 13. The rear projector according to claim 12, wherein the projection optical system emits image light that is P-polarized to the reflection mirror. 14. The rear projector according to claim 12, wherein the projection optical system emits image light that is S-polarized to a reflection mirror. 15. The projection optical system includes a light source and an integrator that converts light emitted from the light source into light having a substantially uniform illuminance distribution, and the projection optical system includes the light source in the optical path between the integrator and the screen. 2. The rear projector according to claim 1, further comprising a brightness uniformity correction means.