JP3346202B2 - Projection optical device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to the irradiation plane uniformly
Projection optical device with an illumination device used for illumination .

[0002]

2. Description of the Related Art Conventionally, there has been known a projection optical apparatus which illuminates an image formed on a light valve such as a transmission type liquid crystal panel from the back side and projects the image by a projection lens. The optical system of an illumination device used in such a projection optical device is required to uniformly illuminate an illuminated surface on which an image is formed, and various illumination devices have been proposed.

As a lighting device suitable for uniformly illuminating a plane, a lens array in which lenses are two-dimensionally arranged between a light emitting portion and a surface to be illuminated includes a first lens array and a first lens array in order from the light emitting portion side. There is a lighting device using an optical integrator in which two light-emitting units are provided as a second lens array, and the light emitting unit and the second lens array, and the first lens array and the surface to be illuminated are optically substantially conjugated. .

In an optical integrator, a light beam emitted from a light-emitting unit is divided into a plurality of light beams by a function of a first lens array and an image is formed in the vicinity of a second lens array. Functions as a light source. Therefore, as viewed from the first lens array, the light flux is superimposed on the illuminated surface, and the illuminated surface can be uniformly illuminated.

As a lighting device using an optical integrator, Japanese Patent Application Laid-Open No. 7-174974 discloses a light emitting portion, an aspherical reflector formed so as to surround the light emitting portion, an aspheric lens, and an optical integrator. An illumination device including two lens arrays and the like is disclosed.

[0006]

The projection lens used in the above-described projection optical apparatus is provided with a light-emitting surface such as a liquid crystal panel (object side) in order to efficiently use a light beam emitted from the light emitting section. ) Has a small open F number (hereinafter simply referred to as the open F number of the projection lens) and is preferably a bright lens. However, a bright projection lens having a small open F-number has a problem that it is difficult to design, and even if it can be designed, it becomes expensive.

[0007] The illumination device described in the above-mentioned publication addresses such a problem by providing an aspheric lens between the reflector and the optical integrator.
In this lighting device, by the function of the aspheric lens described above,
It is stated that since the apparent size of the light emitting unit can be reduced, the open F-number of the projection lens can be increased without lowering the light beam utilization efficiency.

However, the aspherical reflector and the aspherical lens used in the illuminating device described in the above publication have a very complicated shape, and are not easy to design and manufacture, and are expensive. Had.

According to the present invention, there is provided a projection lens which can efficiently utilize a light beam radiated from a light emitting portion without using an expensive aspheric lens which is difficult to design and manufacture, and which is used after an illumination device. It is an object of the present invention to provide a lighting device and a projection optical device which have a large open F number and are low in cost.

[0010]

[0011]

In order to achieve the above object, a projection optical device according to claim 1, further comprising: a light emitting unit that emits a light beam; and a rotating quadratic curved surface shape having the light emitting unit as a focal position. An optical integrator including one reflector, a second reflector having a spherical shape centered on the light-emitting portion, a first lens array and a second lens array in which a plurality of lenses are two-dimensionally arranged, a light valve, and a projection lens And satisfying the following conditional expression range.
Sign.

(Equation 1) Here, Fp is the open F number of the projection lens, P is the length of the light valve in the short side direction, and d is the length of the light emitting unit in the optical axis direction .

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A liquid crystal projector according to an embodiment of the present invention will be described below with reference to the drawings. [First Embodiment] FIG. 1 is a configuration diagram showing an arrangement of optical elements of a liquid crystal projector according to a first embodiment of the present invention.

In FIG. 1, a liquid crystal projector device according to a first embodiment generally includes a light emitting unit 101, a first reflector 102,
A second reflector 103, a first lens array 104 and a second lens array 105 constituting an optical integrator,
Liquid crystal panels 106R, 106G, 106B, projection lens 107, IR-UV cut filter 108, dichroic mirrors 109 and 110,
Reflecting mirrors 111 to 113, relay lenses 114 and 115, field lenses 116R, 116G, 116B, dichroic prism
It consists of 117 mags.

The light emitting section 101 is a metal halide lamp that emits white light. The first reflector 102 disposed so as to cover the light emitting unit 101 has a parabolic reflective surface having the light emitting unit 101 as a substantially focal position.

The first reflector 102 has a shape symmetrical with respect to a line (hereinafter, referred to as an optical axis) connecting the focal point and the vertex of the paraboloid. May be defined as the half value of the angle formed by the cross section of the reflecting surface with respect to the focal point when cut at the focal point and a plane passing through the vertex of the paraboloid. In the present specification, the aforementioned optical axis is 0 °, and the angle formed with respect to the optical axis is θ (where 0 ° ≦
θ ≦ 180 °).

The half value θ of the angle of taking in the light beam emitted from the light emitting section 101 of the first reflector 102 is 90 °, and the open end is located at 90 °. The second reflector 103 includes a light emitting unit 101
And a reflection surface having a spherical shape centered at the center, and the reflection surface is arranged at a position that does not overlap with the reflection surface of the first reflector 102 in space. The light emitting unit 101 of the second reflector 103
Is equivalent to 90 ° to 135 ° in terms of the capturing angle θ of the first reflector 102.

The IR-UV cut filter 108 is disposed in the opening formed by the above-mentioned second reflector 103, and forms red (R), green (G), and blue (B) for forming a color image.
This is a filter for removing light in a wavelength range that is unnecessary for the light of the three primary colors.

The second part of the optical integrator
Each of the one lens array 104 and the second lens array 105 is constituted by a plurality of rectangular positive lenses arranged two-dimensionally. These positive lenses all have the same aperture shape,
The first lens array 104 and the second lens array 105 form the same number of positive lenses. The light emitting unit 101 and the second lens array 105 are in an optically conjugate relationship with respect to the first lens array 104, and the first lens array 104 and liquid crystal panels 106R, 106G, and 106B described later are connected to the second lens array 105 Are optically conjugated to each other.

The dichroic mirrors 109 and 110 convert the luminous flux whose unnecessary wavelength range has been cut by the above-mentioned IR-UV cut filter 108 into red (R), green (G) and blue light.
An interference film for dividing into three wavelength bands (B) is formed, has a predetermined cutoff value, and transmits / reflects a light beam of a predetermined wavelength according to the cutoff value.

The field lenses 116R, 116G and 116B have positive refractive power, and correspond to the corresponding liquid crystal panels 106R and 106R, respectively.
6G and 106B. Field lens 116
R, 116G, and 116B have a function of making the incident light beams substantially parallel to emit light, and perform telecentric illumination that makes the incident angle of the light beams incident on the liquid crystal panels 106R, 106G, and 106B constant.

The liquid crystal panels 106R, 106G, and 106B are transmissive liquid crystal panels, and correspond to red (R), green (G), and blue (B) components of a color image according to an image signal from a controller (not shown). To be formed, respectively.

The dichroic prism 117 is formed by providing predetermined interference films on two surfaces of four right-angle prisms and joining them to combine RGB image signals.

The projection lens 107 is an optical system for enlarging and projecting the color image synthesized by the dichroic prism 117 onto a screen (not shown), and is composed of a plurality of lenses.

Next, the operation of the liquid crystal projector having the above configuration will be described. Of the luminous flux emitted from the light emitting unit 101, the luminous flux radiated to the first reflector 102 side directly reaches the parabolic reflecting surface of the first reflector 102, is reflected and reflected by the IR-UV cut filter 108. To reach. At this time, since the light emitting unit 101 is disposed at the focal position of the parabolic surface of the first reflector 102, the light beam directly reaching the first reflector 102 from the light emitting unit 101 becomes a substantially parallel light beam and becomes a first parallel light beam. Emitted from 102.

On the other hand, of the light beams emitted from the light emitting unit 101, the light beam directly reaching the second reflector 103 is reflected by the spherical reflecting surface of the second reflector 103 and is turned back toward the light emitting unit 101. Thereafter, the light reaches the reflection surface of the first reflector 102, and is reflected by the reflection surface having a parabolic shape, like the light beam directly reaching the first reflector 102, and reaches the IR-UV cut filter 108. . At this time,
Since the light emitting unit 101 is formed at the center position of the spherical surface of the second reflector 103, the light beam reflected by the reflecting surface of the second reflector 103 returns to the light emitting unit 101 again. Therefore, the light beam reflected by the second reflector 103 is also reflected by the reflection surface of the first reflector 102 having the parabolic shape,
The light is emitted from the first reflector 102 as a substantially parallel light beam.

The luminous flux reaching the IR-UV cut filter 108 is filtered by this filter into red (R), green (G), blue
The unnecessary wavelength range for the light of the three primary colors (B) is cut, and the light enters the first lens array 104. The first lens array 104 divides the incident light beam by the number of positive lenses forming the lens array, forms an image near the second lens array 105 by the refractive power of the positive lens, and has the same number of light beams as the number of split light beams. Form a secondary light source. At this time, since the first lens array 104 and the liquid crystal panels 106R, 106G, and 106B are arranged in an optically conjugate relationship as described above, light is emitted from the secondary light source formed near the second lens array 104. The light beams thus obtained are superimposed on the liquid crystal panels 106R, 106G, and 106B. Therefore, the liquid crystal panel 106 has a uniform light amount distribution.
It becomes possible to illuminate the surfaces of R, 106G and 106B.

The light beam emitted from the second lens array 105 enters the dichroic mirror 109. The dichroic mirror 109 has a cutoff wavelength that transmits only a light beam in a wavelength band corresponding to the red (R) wavelength band and reflects a light beam in the other wavelength band, and forms a second optical integrator. Lens array 105
Out of the luminous flux emitted from, only the components in the red (R) wavelength band are separated. The red (R) component is reflected by the reflection mirror 111, enters the field lens 116R,
The liquid crystal panel 106R is uniformly illuminated from the same direction.

On the other hand, the component reflected by the dichroic mirror 109 enters the dichroic mirror 110. The dichroic mirror 110 has a cutoff wavelength that reflects only the luminous flux in the wavelength band corresponding to the green (G) wavelength band and transmits the luminous flux in other wavelength ranges, and is reflected by the dichroic mirror 109. Out of the luminous flux
Only components in the green (G) wavelength band are separated. The green (G) component enters the field lens 116G and illuminates the liquid crystal panel 106G uniformly from the same direction.

The component transmitted through the dichroic mirror 110 is substantially a blue (B) component, and the relay lens 114 arranged to make the optical path length equal.
And 115, and the reflection mirrors 112 and 113, and enters the field lens 116B, and uniformly illuminates the liquid crystal panel 106B from the same direction.

The light fluxes transmitted through the liquid crystal panels 106R, 106G, and 106B, each of which is telecentricly illuminated with a uniform light amount distribution, enter the dichroic prism 117. Dichroic prism 117 has a red (R) inside
Interference film 117a, which reflects only the luminous flux of
(B) has an interference film 117b that reflects only the wavelength band,
Light beams transmitted through the liquid crystal panels 106R, 106G, and 106B are combined and emitted in the same direction. The color image synthesized in this manner is projected onto a screen (not shown) by the projection lens 107.

Next, the optimum open F-number of the projection lens of the liquid crystal projector of the first embodiment will be described in more detail with reference to FIG. FIG. 2 is a configuration diagram schematically illustrating the arrangement of the illumination optical system in the liquid crystal projector device of FIG. 1 described above. For convenience of explanation, dichroic mirrors, dichroic prisms, and reflection mirrors, which are not directly related to the operation of the illumination optical system, are omitted.
In addition, for simplification of description, illustration of a field lens is also omitted. 2, the same components are denoted by the same reference numerals as in FIG.
The configurations of the first reflector 102, the second reflector 103, the first lens array 104, the second lens array 105, the liquid crystal panel 106, and the like are as described with reference to FIG.

In FIG. 2, assuming that the open F-number of the illumination light beam on the liquid crystal panel 106 is Fs, the open F-number Fs is represented by the following equation (1).

[0033]

(Equation 3)

Where R2 is the effective radius of the second lens array 105, and L is the distance between the second lens array 105 and the liquid crystal panel 106.

When the first lens array 104 and the liquid crystal panel 106 are in an optically conjugate relationship, the first lens array 1 is required to illuminate the surface of the liquid crystal panel 106 efficiently.
It is desirable that the size of the opening of each lens of 04 be matched with the size P of the liquid crystal panel 106. This is because if the opening of the first lens array 104 projected on the liquid crystal panel 106 is smaller than that of the liquid crystal panel 106, an area that is not illuminated on the liquid crystal panel 106 is formed, which is inconvenient. Conversely, the first lens array 104 projected on the liquid crystal panel 106
If the opening is too large compared to the liquid crystal panel 106, an area much larger than the liquid crystal panel 106 will be illuminated, and the illumination light will be wasted. Also, the first
If the shape of the opening of each lens of the lens array 104 is too different from the shape of the liquid crystal panel 106, the waste of illumination light will also increase.

From the above, it is desirable that the individual lenses of the first lens array 104 and the liquid crystal panel 106 have substantially similar shapes and satisfy the following conditions. W1: P = m: L (2) where W1: effective diameter of each lens included in the first lens array 104, P: size of the liquid crystal panel 106, m: first lens array 104 and second lens L: the distance between the second lens array 105 and the liquid crystal panel 106. In the case of the first embodiment, the second lens array 1
The size d ′ of the image of the light-emitting unit 101 formed on the surface 05 is controlled by the length of one of the liquid crystal panels 106 in the short side direction. Think Sato. By substituting the above equation (2) into the equation (1), the following equation (3) is obtained.

[0037]

(Equation 4)

On the other hand, as described above, the light emitting unit 101 and the second lens array 105 are in an optically conjugate relationship, and in order to perform efficient illumination, the light emitting unit 101 projected on the second lens array 105 is required. It is desirable that the size of the image be smaller than the size of each lens of the second lens array 105. This is because, when the size of the image of the light emitting unit 101 is larger than the individual lenses of the second lens array 105, the image of the light emitting unit 101 protruding from the individual lenses of the second lens array 105 is
This is because the light is not guided upward and does not become illumination light.

As described above, the light emitting unit 101 and the second lens array 1
05 desirably satisfies the following conditions. W2 ≧ d ′ (4) where W2: effective diameter of each lens included in the second lens array 105, and d ′: size of the light emitting unit 101.

In general, the light-emitting portion of a metal halide lamp or a xenon lamp used as a light-emitting portion has a predetermined length, not a point light source. Therefore, these lamps usually have a light-emitting portion. The direction is used in accordance with the optical axis direction. Therefore, when considering the size of the image of the light emitting unit 101 projected on the second lens array 105,
It is necessary to consider the length of the light emitting unit 101 in the optical axis direction.

Light emitting unit 1 projected on second lens array 105
The size of the image of 01 is calculated from the following equation (5)
Is represented by

[0042]

(Equation 5)

Where d ′ is the size of the image of the light emitting unit 101 projected on the second lens array 105, d is the length of the light emitting unit 101 in the optical axis direction, and α is the main light emitted from the light emitting unit 101. R1 is the effective radius of the first lens array 104; and θ is the half value of the angle at which the light beam is taken into the first reflector 102 from the light emitting unit 101.

The above equation (5) becomes maximum when α is 60 °, and becomes the following equation (6).

[0045]

(Equation 6)

In the case of the first embodiment, the size of each lens of the first lens array 104 and the second lens array 105 is equal, and W1 = W2 and R1 = R2. These conditions and the formula
From (2), the F-number F of the illumination light on the liquid crystal panel 106
s is represented by the following equation (7).

[0047]

(Equation 7)

Equation (7) is obtained by determining the F number of the illuminating light for efficiently illuminating the liquid crystal panel 106 if the size P of the liquid crystal panel 106 and the half value θ of the light beam capturing angle of the first reflector 102 are determined. This indicates that the maximum value of Fs is determined.

On the other hand, the open F-number Fp of the projection lens 107 for efficiently projecting the illumination light on the liquid crystal panel 106 onto the screen only needs to satisfy the relationship of Fs ≧ Fp.
Accordingly, conditions are imposed on the open F-number Fp of the projection lens 107.

Generally, the projection lens 107 has an open F-number.
The larger the value of Fp, the easier the design is, and a compact and low-cost projection lens can be obtained. Therefore, it is desirable that the open F-number Fp of the projection lens 107 satisfies the following condition.

[0051]

(Equation 8)

As can be seen from the above equation (8), the light emitting portion 101
The half angle θ of the light beam capture angle of the first reflector 102 from the
Is smaller, the Fp can be increased. However, in reality, the light beam is emitted from the light emitting unit 101 to a region where the half value θ of the light beam capturing angle with respect to the first reflector 102 is 135 ° or more. In order to use more light beams as illumination light, it is desirable that θ be large.

Therefore, in the projection device of the first embodiment, the first reflector 102 is used to capture the light beam in a region where the half value θ of the light beam from the light emitting unit 101 is 90 ° or less, and the projection lens 107 is opened. In order to capture more light as illumination light while increasing the F-number Fp sufficiently,
A reflector 103 is provided, and a light beam is substantially emitted from the first reflector 1.
Converted to the capture angle of 02, it is captured from the range of 90 ° to 135 °.

By adopting the above configuration,
Without reducing the open F-number Fp of the projection lens 107, it is possible to greatly improve the utilization efficiency of the illumination light. That is, since the half-value θ of the light flux taking-in angle by the first reflector 102 is 90 °, the open F-number of the projection lens 107 may be a value corresponding to 90 °, and the open F-number of the projection lens 107 is required. There is no need to make it smaller. On the other hand, since the light beam is captured by the second reflector 103, the light beam from the light source of substantially 0 ° to 135 ° is used as the illumination light, and a wide range of the illumination light can be used. It is.

The open F number of the projection lens 107 in this case
Fp is expressed as follows by setting θ = 90 ° in the above equation (8).

[0056]

(Equation 9)

On the other hand, as in the first embodiment, the second
Without using the reflector 103, only the first reflector 102,
If an attempt is made to use a light beam of 0 ° to 135 ° emitted from the light emitting unit, the open F-number Fp of the projection lens 107 becomes small as in the following equation, and the design of the projection lens 107 becomes difficult.

[0058]

(Equation 10)

The case where the shape of the first reflector 102 is a paraboloid has been discussed above by taking the first embodiment as an example. The optimal value of the open F-number Fp of the projection lens 107 is generally more rotationally symmetric. This is also effective for a reflection surface having a second curved surface. Hereinafter, this point will be briefly described. Generally, the reflecting surface of a reflector having a rotationally symmetric quadratic surface shape such as a spherical surface, a spheroidal surface, a paraboloid, or a hyperboloid, which is easy to design and manufacture and can be manufactured at low cost, is represented by the following equation (11). be able to.

[0060]

[Equation 11]

Where c is the curvature at the vertex of the reflector, x is the optical axis, y is the coordinate axis passing through the vertex of the reflector and perpendicular to the optical axis, and ε is the coefficient.

Ε is also called a quadratic surface parameter, and the surface shape is defined by the following values. (a) When ε> 0, a spheroid, especially when ε = 1, a spherical surface, (b) When ε = 0, a paraboloid, (c) When ε <0, a hyperboloid, When the reflector has the shape represented by the above formula (11), and there is no power other than the individual lenses constituting the first lens array 104 for simplicity (i.e., when the lens array itself does not have the base curvature) ), The projection lens 1
The optimal open F-number Fp of 07 can be represented by the following equation (12).

[0063]

(Equation 12)

However, each parameter is the same as in equation (8).

In the above equation (12), the first reflector 10
Assuming that the half value θ of the luminous flux take-in angle of 2 is 90 °, the optimum value of the projection lens Fp is represented by the following equation (13).

[0066]

(Equation 13)

Here, P is considered on the short side of the length of the liquid crystal panel.

In the above equation (13), if ε = 0, the equation naturally coincides with the equation (9). Here, when the above equation (13) is considered as a function of ε, and this increase / decrease is examined, the increase / decrease of Fp is within 5% in the following range indicating a practically usable shape including a parabolic surface shape. −1.22 ≦ ε ≦ 0.55 (14) Accordingly, the optimum value of the open F-number Fp of the projection lens for the shape of the reflector that can be practically used may be the value shown in Expression (12).

When actually designing the projection lens, the value of the open F-number Fp of the projection lens is 1
An allowable value of 0% may be provided, and within a range represented by the following formula (A), the luminous flux radiated from the light emitting unit can be used efficiently while sufficiently designing the projection lens.

[0070]

[Equation 14]

FIG. 8 shows a case where only the first reflector 102 is provided in the light emitting portion, with the open F number Fp of the projection lens on the vertical axis and the ratio P / d of the optical axis length between the liquid crystal panel and the light emitting portion on the horizontal axis. ,
5 is a graph comparing a case where a second reflector 103 is arranged together with a first reflector 102.

In the graph of FIG. 8, the bold solid line indicates that the angle at which the light beam is captured by the first reflector 102 is 0 as in the first embodiment.
9090 °, and the angle at which the light beam is captured by the second reflector 103 is converted to the angle of capture of the first reflector 102 by 90 ° to 135 °.
Indicates the value of equation (9), and the upper and lower sides indicate the range defined by equation (14). In addition, the thick dotted line indicates Fp and P / d when the angle of taking in the light beam of the first reflector 102 is set to 0 to 90 ° and the second reflector 103 is not provided in the above configuration.
Shows the relationship between the values of.

As can be seen from the graph, when the second reflector 103 is used, a projection lens having a large F-number can be used naturally, and a low-cost projection lens can be used.

[Second Embodiment] Next, referring to FIG.
An embodiment will be described. FIG. 3 is a schematic diagram illustrating the configuration of the projection optical device according to the second embodiment. In FIG.
The liquid crystal projector device according to the third embodiment generally includes a light emitting unit.
301, a first reflector 302, a second reflector 303, a first lens array 304 constituting an optical integrator
And second lens array 305, liquid crystal panels 306R, 306G, 306
B, projection lens 307, IR-UV cut filter 308, dichroic mirrors 309 and 310, reflection mirrors 311-313, relay lenses 314 and 315, field lenses 316R, 316G, 316
B, dichroic prism 317, polarization separation surface 31 described later
It comprises a polarizing beam splitter 318 and the like having an 8a and a total reflection surface 318b.

The structures of the light emitting section 301, the first reflector 302, the second reflector 303, the IR-UV cut filter 308, and the first lens array 304 constituting the optical integrator are the same as those in the first embodiment. Description is omitted.

The polarization beam splitter 318 is a separation section of the triangular polarization conversion optical system, and the first lens array 304
Are separated into a first linearly polarized light component 319 and a second linearly polarized light component 320 whose polarization directions are orthogonal to each other. Polarizing beam splitter 3
A polarization separation surface 318a is formed on the rear surface, which is the inclined surface of the right-angle prism included in 18, and the first linearly polarized light component of the light flux emitted from the first lens array 304 is 45 ° at the polarization separation surface 318a. Reflected at a right angle to the incident angle of
Are emitted from the polarization beam splitter 318. On the other hand, the total reflection surface 318b is formed so as to face the polarization separation surface 318a at an interval of the thickness 318c, and is orthogonal to the first linearly polarized light component of the light beam incident from the first lens array 304. The second linearly polarized light component
And is reflected at a right angle to the incident angle of 45 °, and is emitted from the polarizing beam splitter 318 as a light beam 320. The dimension of the thickness 318c is determined by the pitch (thickness 318) at which the light beams 319 and 320 are emitted.
(approximately 1.414 times c) and the pitch of the individual lenses constituting the second lens array 305.

The second lens array 305 constituting the optical integrator is composed of a plurality of positive lenses arranged two-dimensionally, and a polarizing beam splitter 318.
The plurality of light fluxes 319 and 320 separated by are arranged in the vicinity where they are converged by the first lens array 304. That is, the light emitting unit 301 and the second lens array 305 are in an optically conjugate relationship with respect to the first lens array 304. Also,
The positive lenses forming the second lens array 305 all have the same aperture shape, and the number of the plurality of light beams 319 and 320 separated by the polarizing beam splitter 318, that is, twice the number of lenses forming the first lens array 304. The two lenses adjacent to each other in the left-right direction in FIG. 3 correspond to one lens in the first lens array 304, respectively. The first lens array 304 and the liquid crystal panels 306R, 306G, 306B are arranged so as to be in an optically conjugate relationship with respect to the second lens array 305. Further, of the individual lenses constituting the second lens array 305, a half-wave plate 305a is provided on a surface on which the second linear polarization component 320 is incident, and the polarization direction of the second linear polarization component 320 is provided. Is rotated by 90 ° to convert the polarization direction to the same direction as the polarization direction of the first linearly polarized light component. Note that this polarization beam splitter 318
And the half-wave plate 305a constitute a polarization conversion optical system.

Dichroic mirrors 309 and 310, field lenses 316R, 316G, 316B, liquid crystal panels 306R, 306G,
The configurations of the 306B, the dichroic prism 317, the projection lens 307, the relay lenses 315 and 314, and the like are the same as those in the first embodiment, and a description thereof will be omitted.

Next, the operation of the liquid crystal projector of the second embodiment having the above configuration will be described. Light emitting unit
Of the light beams emitted from 301, the light beam emitted to the first reflector side directly reaches the parabolic reflecting surface of the first reflector 302, is reflected and reaches the IR-UV cut filter 308. . At this time, since the light emitting unit 301 is disposed at the focal position of the parabolic surface of the first reflector 302,
The light beam directly reaching the first reflector 302 from the light emitting unit 301 is emitted from the first reflector 302 as a substantially parallel light beam.

On the other hand, of the light beams emitted from the light emitting unit 301, the light beam that directly reaches the second reflector 303 is reflected by the spherical reflecting surface of the second reflector 303 and is turned back toward the light emitting unit 301. Thereafter, the light reaches the reflection surface of the first reflector 302, and is reflected by the reflection surface having a parabolic shape, like the light beam directly reaching the first reflector 302, and reaches the IR-UV cut filter 308. . At this time,
Since the light emitting unit 301 is formed at the center position of the spherical surface of the second reflector 303, the light beam reflected on the reflecting surface of the second reflector 303 returns to the light emitting unit 301 again. Therefore, the light beam reflected by the second reflector 303 is also reflected by the reflecting surface of the first reflector 302 having the parabolic shape.
The light is emitted from the first reflector 302 as a substantially parallel light beam.

At this time, the light beam emitted from the light emitting section is a randomly polarized light, and includes all polarized light components.
Therefore, the light beam reflected by the first reflector 302 and the second reflector 303 and incident on the first lens array 304 constituting the optical integrator includes all polarization components.

The luminous flux reaching the IR-UV cut filter 308 is filtered by this filter into red (R), green (G), blue
The unnecessary wavelength range for the light of the three primary colors (B) is cut, and the light enters the first lens array 304. The first lens array 304 divides the incident light beam by the number of positive lenses forming the lens array.

The luminous flux divided by the number of lenses of the first lens array 304 enters the polarization beam splitter 318. In the polarization beam splitter 318, the first linearly polarized light component of the incident light beam is reflected by the polarization separation surface, and
The light exits the polarizing beam splitter 318 as 319. On the other hand, the second linearly polarized light component orthogonal to the first linearly polarized light component is reflected by the total reflection surface and emitted from the polarization beam splitter 318 as a light beam 320. Therefore, the light flux 319 and the light flux 320 are separated from each other by the amount of lateral shift 321 caused by the distance between the polarization separation surface 318b and the total reflection surface 318c, and the second lens array 3
Reach 05. As described above, the light emitting unit 301 and the second
Since the light beam 319 and the light beam 320 are arranged in an optically conjugate relationship with the lens array 305, the second lens array 305
Is formed in the vicinity of.

Further, a half-wave plate 305a is provided at a position corresponding to the light beam 320 on the incident surface of the second lens array 305. Since the polarization direction of the linearly polarized light of the light beam 320 incident on the half-wave plate 305a is rotated by 90 °, the polarization separation unit 318a is consequently obtained.
The light flux 319 reflected by the light is aligned with the polarization direction, and is incident on the second lens array 305. In this way, by aligning the polarization components of all the light beams, the light beam 319 and the light beam 320 can behave in the same manner on the reflecting surface or the like, which is preferable for uniform illumination. Note that a half-wave plate
305a is not the light beam 320 side as in the second embodiment, but the light beam 3
Even if formed at a position corresponding to 19, the polarization of the light beam 319 is 90 °
Due to the rotation, all polarization directions can be aligned. However, it is preferable to form it at a position corresponding to the light beam 320 as in the second embodiment because a further effect of correcting the optical path difference between the light beam 319 and the light beam 320 can be obtained.

As a result, a number of secondary light sources having the same polarization direction, twice the number of light beams divided by the first lens array 304, are formed near the second lens array 305. At this time, since the first lens array 304 and the liquid crystal panels 306R, 306G, and 306B are arranged in an optically conjugate relationship as described above, light is emitted from the secondary light source formed near the second lens array 304. The emitted luminous flux is the liquid crystal panel 306R,
It will be superimposed on 306G and 306B. Therefore, it is possible to illuminate the surfaces of the liquid crystal panels 306R, 306G, and 306B with a uniform light amount distribution. The behavior of the luminous flux after exiting from the second lens array 305 until being taken into the projection lens 307 is the same as in the first embodiment described above, and a description thereof will be omitted.

Next, the optimum value of the open F-number Fp of the projection lens in the case of the second embodiment will be described. Also in the case of the second embodiment, the general discussion is the same as the discussion performed on the first embodiment with reference to FIG. Therefore, only the results are shown below.

In the case of the second embodiment, the expression corresponding to the expression (12) for the first embodiment has the following format.

[0088]

[Equation 15]

However, the parameters used are represented by the formula (1)
Same as 2). In this case, the difference from the equation (12) for the first embodiment is that the number of individual lenses of the first lens array 303 and the number of individual lenses of the second lens array 304 constituting the optical integrator are different. This is because one lens array 304 is further generalized to obtain a case where the lens array itself has a base curvature.

In the above equation (15), the first reflector 30
Assuming that the half value of the luminous flux taking-in angle 2 is θ = 90 °, the optimal value of the projection lens Fp is as shown in the following equation (16).

[0091]

(Equation 16)

Here, P is considered on the long side of the length of the liquid crystal panel.

As in the case of the first embodiment, the above equation (16)
Is considered as a function of ε, and this increase / decrease is examined. In the following range indicating a practically usable shape including a parabolic shape, the increase / decrease of Fp is within 5%. −11.03 ≦ ε ≦ 0.91 (17) Accordingly, the optimum value of the open F-number Fp of the projection lens for the shape of the reflector that can be practically used may be set to the value shown in Expression (17). In this case, the value of the open F-number Fp of the projection lens may have an allowable value of 10% with respect to the above-mentioned optimum value, and the design of the projection lens is sufficiently easy as long as it is within the range represented by the following equation (B). In this case, the luminous flux emitted from the light emitting unit can be used efficiently.

[0094]

[Equation 17]

[Other Embodiments] Next, modified examples of the first and second embodiments will be described with reference to the drawings showing the main parts of the projection optical device. In each of the drawings, members denoted by the same reference numerals as those in FIGS. 1 and 3 have the same configuration.

FIG. 4 is a diagram showing a main part of a modified embodiment of the first embodiment, in which the shape of the first reflector 402 is the light emitting unit 101.
All have the same configuration as the first embodiment except that the spheroid has one focal point.

FIG. 5 is a diagram showing a main part of a modified embodiment of the second embodiment. Similar to FIG. 4, the shape of the first reflector 502 is a spheroid having the light emitting unit 101 as one focal point. Except for adding a concave base curvature to the first lens array 504 in order to convert a light beam incident on the polarization splitting surface into parallel light for efficient polarization conversion, all have the same configuration as the second embodiment. are doing.

As shown in FIGS. 4 and 5, when the shape of the first reflector is a spheroid having the light-emitting portion 101 as one focal point, the light beam emitted from the first reflector becomes convergent light. The curvature of the lens that constitutes the reflector can be reduced, and the illumination light can be guided to a predetermined position on the liquid crystal panel even if the alignment accuracy of the light emitting unit configuration with respect to the liquid crystal control panel or the like is somewhat poor, The assemblability of the device can be improved. There is also an advantage in reducing the size of the optical integrator.

FIG. 6 is a main part configuration diagram showing another modified embodiment of the first embodiment. The first embodiment is the same as the first embodiment except that the shape of the first reflector 402 is a hyperboloid having the light emitting portion 101 as a focal point. It has the same configuration as the form.

FIG. 7 is a configuration diagram of a main part showing another modified embodiment of the second embodiment. Similar to FIG. 6, the shape of the first reflector 502 is a hyperboloid having the light emitting portion 101 as a focal point, and the efficiency is improved. All have the same configuration as the second embodiment except that a convex base curvature is added to the first lens array 504 in order to make the light beam incident on the polarization splitting surface into parallel light for good polarization conversion. ing.

As shown in FIGS. 6 and 7, when the shape of the first reflector is a hyperboloid having the light-emitting portion 101 as the focal point, the light beam emitted from the first reflector becomes divergent light, and is effective in the first reflector. The reflecting surface can be made smaller,
There is an advantage that the configuration of the light source unit of the lighting device including the light emitting unit can be reduced in size.

The present invention is not limited to the configuration of each of the embodiments described above, and can be appropriately changed without departing from the gist of the present invention. For example, the light emitting unit may be not only a metal halide lamp but also various lamps such as a xenon lamp and a halogen lamp, and is not particularly limited. An image display element such as a DMD element may be used for a transmission type liquid crystal panel as a light valve for projecting an image.

[0103]

【Example】

[First Example] Specific numerical values are shown for a first example that embodies the projection optical device of the first embodiment. In the projection optical device of the first embodiment, the length d of the light emitting unit 101 in the optical axis direction is 3 m.
m metal halide lamp, and
The half value of the luminous flux take-in angle by the reflector 102 is 0 ° to 90 °.
°, the half value of the light beam take-in angle by the second reflector 103 is 90 ° to 135 °, and the size of the opening emitted to the optical integrator is φ50 mm. Also, the first lens array 103 and the second lens
The distance m between the lens arrays 104 is 70 mm, and the size W1 (W2) of each lens constituting the first and second lens arrays 104 and 105
10.9mm x 14.5mm, LCD panel size is 21mm x 28mm
(That is, P: 21 mm), the maximum size of the secondary light source image is 10.9.
mm. With the above configuration, the liquid crystal panels 106R, 106R
The surfaces of G and 106B could be uniformly illuminated.

The optimum open F-number Fp of the projection lens used in this projection optical device is 2.7, and a projection lens having a sufficiently large open F-number can be used.

[Second Example] Specific numerical values are shown for a second example that embodies the projection optical apparatus of the second embodiment. In the projection optical device of the second embodiment, a metal halide lamp having a length d of 3 mm in the optical axis direction of the light emitting section 301 is used, and the half value of the light flux taking-in angle by the first reflector 302 is 0 ° to 90 ° as described above. The half value of the luminous flux taking-in angle by the second reflector 303 was 90 ° to 135 °, and the size of the opening emitted to the optical integrator was φ70 mm. Also,
The distance m between the first lens array 303 and the second lens array 304 constituting the optical integrator is 70 mm, and the size W1 of each lens constituting the first lens array 304 is 11.7 m.
m × 15.6 mm, the size W2 of each lens constituting the second lens array 305 is 11.7 mm × 7.8 mm, and the size of the liquid crystal panel is 2
1 mm × 28 mm (that is, P: 28 mm), and the maximum size of the secondary light source image is 7.8 mm. With the above configuration, the LCD panel 3
The surfaces of 06R, 306G, and 306B could be uniformly illuminated.

The optimum open F-number Fp of the projection lens used in this projection optical apparatus is 1.4, and a projection lens having a sufficiently large open F-number can be used.

As described above, according to the projection optical apparatus of the present invention, in the illumination device, the first reflector having a secondary curved surface and the second reflector having a spherical shape, which can be easily processed, are provided around the light emitting portion. By arranging and defining the necessary conditional expression range, the light valve that is the illuminated surface can be efficiently and uniformly illuminated, and the open F-number of the projection lens used after the illumination device is increased. It is possible to achieve the effect.

[Brief description of the drawings]

FIG. 1 is a schematic diagram illustrating a configuration of a projection optical device according to a first embodiment.

FIG. 2 is a schematic diagram illustrating the illumination principle of the projection optical device according to the first embodiment.

FIG. 3 is a schematic diagram illustrating a configuration of a projection optical device according to a second embodiment.

FIG. 4 is a schematic diagram illustrating a main configuration of a modification of the projection optical apparatus according to the first embodiment.

FIG. 5 is a schematic diagram illustrating a main configuration of a modification of the projection optical apparatus according to the second embodiment.

FIG. 6 is a schematic diagram showing a main configuration of another modified example of the projection optical device of the first embodiment.

FIG. 7 is a schematic diagram illustrating a main configuration of another modified example of the projection optical device of the second embodiment.

FIG. 8 is a graph comparing the case where the light emitting unit of the first embodiment has only the first reflector 102 with the case where the second reflector 103 is arranged together with the first reflector 102;

[Explanation of symbols]

 101, 301: light emitting units 102, 302, 402, 502: first reflector 103, 303: second reflector 104, 304, 404, 504: first lens array 105, 306: second lens array 106, 306: liquid crystal panel 107, 307: Projection lens 318: Polarization separation unit

Claims (1)

(57) [Claims] A light emitting unit that emits a light beam; a first reflector having a quadratic curved surface with the light emitting unit as a focal position;
A second reflector having a spherical shape centered on the light emitting portion;
And an optical integrator consisting of the first and second lens arrays in which a plurality of lenses are two-dimensionally, comprising: a light valve, a projection lens, the projection, characterized by satisfying the expression following ranges Optics
Apparatus: [Equation 1] Here, Fp is the open F number of the projection lens, P is the length of the light valve in the short side direction, and d is the length of the light emitting unit in the optical axis direction .