阅读说明：本技术 投射型图像显示装置 (Projection type image display apparatus ) 是由 在原康贵 相崎隆嗣 于 2019-07-10 设计创作，主要内容包括：提供一种能够避免透镜单元的边界的台阶产生的对图像质量的不好影响的投射型图像显示装置。投射型图像显示装置包括复眼透镜和偏振光转换元件。在复眼透镜的第一方向上相邻的透镜单元的边界上存在台阶,在与第一方向正交的第二方向上相邻的透镜单元的边界上不存在台阶。透过透镜单元的第一方向的中央部的中心光入射到偏振光转换元件的偏振光分离面,偏振光分离面对中心光所包含的第一偏振光进行反射并使第二偏振光透过。反射面对由偏振光分离面反射的第一偏振光进行反射并使其从偏振光转换元件射出,被入射的1/2波长板将透过了偏振光分离面的第二偏振光转换为第一偏振光并使其从偏振光转换元件射出。(Provided is a projection type image display device capable of avoiding adverse effects on image quality caused by steps at the boundary of a lens unit. The projection type image display apparatus includes a fly-eye lens and a polarized light conversion element. There is a step on the boundary of the lens cells adjacent in the first direction of the fly-eye lens, and there is no step on the boundary of the lens cells adjacent in the second direction orthogonal to the first direction. The central light transmitted through the central portion of the lens unit in the first direction enters the polarization splitting surface of the polarization conversion element, and the polarization splitting surface reflects the first polarized light included in the central light and transmits the second polarized light. The reflection surface reflects the first polarized light reflected by the polarization separation surface and causes the first polarized light to exit from the polarization conversion element, and the incident 1/2 wavelength plate converts the second polarized light transmitted through the polarization separation surface into the first polarized light and causes the first polarized light to exit from the polarization conversion element.)

1. A projection type image display apparatus comprising:

a first fly-eye lens that divides an incident light flux into partial light fluxes for each of first lens units, the first lens units being arranged in a first direction and a second direction orthogonal to the first direction;

a second fly-eye lens in which a plurality of second lens units are arranged in the first direction and the second direction, and each partial light flux emitted from each of the first lens units is condensed by each of the second lens units; and

a polarization conversion element that emits the first polarized light used as illumination light out of first polarized light and second polarized light included in light incident from the second fly-eye lens, converts the second polarized light that is not used as illumination light into the first polarized light, and emits the first polarized light,

in the polarization conversion element, a reflection surface that reflects the incident light with a predetermined angle with respect to an incident surface of the light incident from the second fly-eye lens and reflects the incident light, and a polarization separation surface that reflects the first polarized light included in the incident light and transmits the second polarized light are alternately formed in the first direction at an interval of 1/2 where the size of the second lens unit in the first direction is,

a region sandwiched between the reflection surface and the polarization separation surface in the light exit surface of the polarization conversion element is alternately set in the first direction as a polarization conversion region to which an 1/2 wavelength plate is attached and a non-polarization conversion region to which no 1/2 wavelength plate is attached,

the 1/2 wavelength plate is opposed to the plurality of second lens units arrayed in the second direction,

the plurality of second lens units are decentered in each of the first direction and the second direction,

ends of two second lens units adjacent in the first direction on a first boundary of the two second lens units are shifted in a thickness direction of the second fly-eye lens so that there is a step on the first boundary,

ends of two second lens units adjacent in the second direction on a second boundary of the two second lens units coincide with a thickness direction of the second fly-eye lens so that there is no step on the second boundary,

the central light transmitted through the central portion of the second lens unit in the first direction is incident on the polarization splitting surface, which reflects the first polarized light included in the central light and transmits the second polarized light,

a reflection surface on which the first polarized light reflected by the polarization separation surface enters reflects the first polarized light and causes it to be emitted from the polarization conversion element, and an 1/2 wavelength plate on which the second polarized light transmitted by the polarization separation surface enters converts the second polarized light into the first polarized light and causes it to be emitted from the polarization conversion element,

a polarized light splitting surface, which is incident on the peripheral light beam reflected by the reflection surface, reflects the first polarized light beam included in the peripheral light beam and transmits the second polarized light beam,

the 1/2 wavelength plate on which the first polarized light reflected by the polarization separation surface enters converts the first polarized light into the second polarized light and emits the second polarized light from the polarization conversion element, and the other reflection surface on which the second polarized light transmitted by the polarization separation surface enters reflects the second polarized light and emits the second polarized light from the polarization conversion element.

2. The projection type image display apparatus according to claim 1,

the plurality of second lens units are decentered in each of the first direction and the second direction so that the partial light fluxes emitted from the respective second lens units overlap each other.

Technical Field

The present invention relates to a projection type image display device including a pair of fly-eye lenses.

Background

A projection type image display apparatus may include a pair of fly eye lenses in an illumination optical system. Each fly-eye lens includes a plurality of rectangular lens units. In order to improve the performance of the illumination optical system, the lens units included in the fly-eye lens are often decentered.

Prior art documents

Patent document

Patent document 1: japanese patent laid-open No. 2002-23108;

patent document 2: japanese patent laid-open No. 2007-78731.

Disclosure of Invention

The degree of decentering of each lens unit of the fly-eye lens differs depending on the position of the lens unit in the fly-eye lens, and a step is present at the boundary between two adjacent lens units (see patent document 1 or patent document 2). When a fly-eye lens having a step at the boundary is manufactured, a shape error different from the designed shape, which is called "sag" or "notch", occurs at the end of each lens unit. Such shape errors adversely affect the quality of the projected image.

Therefore, a case where the fly-eye lens is designed and manufactured in such a manner that the step of the boundary of the lens unit is eliminated is considered. However, when the shape of the fly-eye lens is corrected so as to eliminate the step at the boundary, the size of the illumination range of each lens unit changes, and the luminance of the light emitted from each lens unit and superimposed becomes uneven in the plane.

An object of the present invention is to provide a projection type image display apparatus capable of minimizing a change in the size of an illumination range of each lens unit of a fly-eye lens and avoiding an adverse effect on image quality due to a step existing at a boundary between adjacent lens units.

The invention provides a projection type image display apparatus, comprising: a first fly-eye lens that divides an incident light flux into partial light fluxes for each of first lens units, the first lens units being arranged in a first direction and a second direction orthogonal to the first direction; a second fly-eye lens in which a plurality of second lens units are arranged in the first direction and the second direction, and each partial light flux emitted from each of the first lens units is condensed by each of the second lens units; and a polarization conversion element that emits the first polarized light used as illumination light out of first polarized light and second polarized light included in light incident from the second fly-eye lens, and converts the second polarized light that is not used as illumination light into the first polarized light to emit the first polarized light.

In the polarization conversion element, a reflection surface that reflects incident light with a predetermined angle with respect to an incident surface of the light incident from the second fly-eye lens and a polarization separation surface that reflects first polarized light included in the incident light and transmits second polarized light are alternately formed in the first direction at an interval of 1/2, which is the size of the second lens unit in the first direction.

In the light exit surface of the polarization conversion element, regions sandwiched between the reflection surface and the polarization separation surface are alternately provided in the first direction as a polarization conversion region to which an 1/2 wavelength plate is attached and a non-polarization conversion region to which a 1/2 wavelength plate is not attached, and the 1/2 wavelength plate faces the plurality of second lens units aligned in the second direction.

The plurality of second lens units are decentered in each of the first direction and the second direction. Ends of two second lens units adjacent in the first direction, which are located on a first boundary of the two second lens units, are shifted in a thickness direction of the second fly-eye lens so that a step is present on the first boundary. Ends of two second lens units adjacent in the second direction on a second boundary of the two second lens units coincide with a thickness direction of the second fly-eye lens so that there is no step on the second boundary.

The central light transmitted through the central portion of the second lens unit in the first direction is incident on the polarization splitting surface, and the polarization splitting surface reflects the first polarized light included in the central light and transmits the second polarized light. The reflection surface on which the first polarized light reflected by the polarization separation surface enters reflects the first polarized light and causes it to be emitted from the polarization conversion element, and the 1/2 wavelength plate on which the second polarized light transmitted by the polarization separation surface enters converts the second polarized light into the first polarized light and causes it to be emitted from the polarization conversion element.

The peripheral light transmitted through the peripheral portion near the first boundary of the second lens unit is incident on the reflection surface, the reflection surface reflects the peripheral light, and the polarized light splitting surface incident on the peripheral light reflected by the reflection surface reflects the first polarized light included in the peripheral light and transmits the second polarized light. The 1/2 wavelength plate on which the first polarized light reflected by the polarization separation surface enters converts the first polarized light into the second polarized light and emits the second polarized light from the polarization conversion element, and the other reflection surface on which the second polarized light transmitted by the polarization separation surface enters reflects the second polarized light and emits the second polarized light from the polarization conversion element.

According to the projection type image display apparatus of the present invention, it is possible to minimize the variation in the size of the illumination range of each lens unit of the fly-eye lens, and to avoid the adverse effect on the image quality caused by the step existing at the boundary between the adjacent lens units.

Drawings

Fig. 1 is a diagram showing an example of the overall configuration of a projection type image display apparatus according to an embodiment;

fig. 2 is a side view of the first fly-eye lens 2, the second fly-eye lens 3, and the polarization conversion element 4 as viewed from the side;

fig. 3 is a plan view of the first fly-eye lens 2, the second fly-eye lens 3, and the polarization conversion element 4 as viewed from above;

fig. 4 is a plan view showing a state where the second fly-eye lens 3 and the polarization conversion element 4 are viewed from the second fly-eye lens 3 side;

fig. 5 is a diagram for explaining the operation of the polarization conversion element 4.

Detailed Description

Hereinafter, a projection type image display apparatus according to an embodiment will be described with reference to the drawings. First, the overall configuration and operation of a projection image display apparatus 100 as an example of the configuration of the projection image display apparatus according to the embodiment will be described with reference to fig. 1.

In fig. 1, a light source 1 emits white light. As an example, the light source 1 is an ultra-high pressure mercury lamp. White light is irregularly polarized light including P-polarized light and S-polarized light. The kind of the light source 1 is not limited, and a Light Emitting Diode (LED) or a laser diode may be used as the light source 1. Depending on the type of the light source 1, the light source 1 may emit light of a color other than white.

The white light is irradiated to the first fly-eye lens 2. The first fly-eye lens 2 has a structure in which a plurality of rectangular lens cells are arranged in a matrix in a first direction in a plane and a second direction orthogonal to the first direction. The first direction and the second direction correspond to a horizontal direction (X direction) and a vertical direction (Y direction) of an image projected by the projection image display apparatus 100, respectively. The first fly-eye lens 2 divides the incident white light beam into partial light beams for each lens unit.

Each portion of the light flux emitted from the first fly-eye lens 2 is irradiated to the second fly-eye lens 3. The second fly-eye lens 3 has a configuration in which a plurality of rectangular lens cells are arranged in a matrix in the X direction and the Y direction in the plane, as in the first fly-eye lens 2. Each lens unit of the second fly-eye lens 3 corresponds to each lens unit of the first fly-eye lens 2 in a one-to-one manner. Each lens unit of the second fly-eye lens 3 individually condenses each partial beam emitted from each lens unit of the first fly-eye lens 2.

Each lens unit of the second fly-eye lens 3 is decentered so that the partial light fluxes emitted from the lens units are converged to overlap each other. The degree of decentering of each lens unit of the second fly-eye lens 3 differs depending on the position of the lens unit. The second fly-eye lens 3 is configured such that, of the X direction and the Y direction, a step is present at the boundary between adjacent lens cells in one direction, and no step is present at the boundary between adjacent lens cells in the other direction.

In fig. 1, the number of lens units of the first fly-eye lens 2 and the second fly-eye lens 3 is reduced, and the drawings are simplified. The number and shape of the lens units of the first fly-eye lens 2 and the second fly-eye lens 3 will be described in detail later.

The partial light beams emitted from the respective lens units of the second fly-eye lens 3 are incident on the polarization conversion element 4. The polarization conversion element 4 converts second polarization light, which is not used as the other of the illumination light, into first polarization light so as to use the first polarization light, which is one of the P-polarized light and the S-polarized light included in each of the partial beams, as the illumination light. For example, in the present embodiment, the first polarized light is S-polarized light, and the second polarized light is P-polarized light.

The polarization conversion element 4 is mainly S-polarized light, and converts P-polarized light into S-polarized light to emit it, but may convert S-polarized light into P-polarized light to emit P-polarized light.

The specific configuration and operation of the polarization conversion element 4 will be described later. In the present embodiment, S-polarized light, which is polarized light at the time point of incidence on the second fly-eye lens 3, is used as the illumination light, but P-polarized light may be used as the illumination light.

The light mainly including the S-polarized light emitted from the polarization conversion element 4 is condensed by the condensing action of the second fly-eye lens 3, and enters the cross-dichroic mirror 6 in a state where the light beams of the respective portions overlap each other. When the lens units of the second fly-eye lens 3 are not decentered and the lens units do not exert a light-collecting effect, a light-collecting lens 5 as shown by a two-dot chain line is required at the subsequent stage of the polarization conversion element 4. By decentering each lens unit of the second fly-eye lens 3, the condenser lens 5 can be omitted.

The cross-dichroic mirror 6 separates incident light into red light (hereinafter, R light), green light (hereinafter, G light), and blue light (hereinafter, B light). The R light and the G light are reflected by the mirror 7, bent in the traveling direction by 90 degrees, and directed toward the dichroic mirror 9. The B light is reflected by the mirror 8 and the traveling direction is bent 90 degrees, and directed toward a Field lens (Field lens) 16.

Of the R light and the G light, the R light passes through the dichroic mirror 9 and is directed toward the field lens 10. The G light is reflected by the dichroic mirror 9, is bent in the traveling direction by 90 degrees, and is directed toward the field lens 13. The field lenses 10, 13, and 16 are lenses for aligning the traveling directions of light in the peripheral portion of the field of view.

The R light transmitted through the field lens 10 is transmitted through the polarizing plate 11 and incident on the red image display element 12. As an example, the polarizer 11 and polarizers 14 and 17 described later are wire grid polarizers. As an example, the red image display element 12, and the green image display element 15 and the blue image display element 18, which will be described later, are reflective liquid crystal display elements. Typically, the reflective Liquid Crystal display element is a spatial light modulation element called LCOS (Liquid Crystal On Silicon).

The red image display element 12 modulates R light according to the red component of the image desired to be projected, and reflects it. The red image display element 12 modulates the R light, whereby the S polarized light is converted into the P polarized light. Thus, the modulated light of the R light reflected by the red image display element 12 is reflected by the polarizing plate 11, is bent in the traveling direction by 90 degrees, and is directed toward the polarizing plate 19 attached to the color synthesis prism 22.

The G light passes through the field lens 13 and the polarizer 14 and enters the green image display element 15. The green image display element 15 modulates the G light in accordance with the green component of the image to be projected, and reflects it. The green image display element 15 modulates the G light, whereby the S polarized light is converted into the P polarized light. Therefore, the modulated light of the G light reflected by the green image display element 15 is reflected by the polarizer 14, and the traveling direction is bent by 90 degrees, and directed toward the polarizer 20 attached to the color synthesis prism 22.

The B light passes through the field lens 16 and the polarizer 17 and enters the blue image display element 18. The blue image display element 18 modulates the B light in accordance with the blue component of the image to be projected, and reflects it. The blue image display element 18 modulates the B light, whereby the S polarized light is converted into the P polarized light. Therefore, the modulated light of the B light reflected by the blue image display element 18 is reflected by the polarizer 17, is bent in the traveling direction by 90 degrees, and is directed toward the polarizer 21 attached to the color synthesis prism 22. As an example, the polarizing plates 19, 20, and 21 are wire grid polarizing plates.

The polarizers 19, 20, and 21 remove unnecessary S-polarized light included in the incident R light, G light, and B light, respectively. Therefore, only the necessary P-polarized light is incident on the color synthesis prism 22. The color synthesis prism 22 performs color synthesis of the R light, the G light, and the B light, and emits the synthesized light toward the projection lens 23. The projection lens 23 projects the synthesized light to a screen not shown in the figure in an enlarged manner. As described above, the projection type image display apparatus 100 displays an image on a screen.

The configurations of the first fly-eye lens 2, the second fly-eye lens 3, and the polarization conversion element 4, and the relationship between the second fly-eye lens 3 and the polarization conversion element 4 will be described with reference to fig. 2 and 3. Fig. 2 shows a state where the first fly-eye lens 2, the second fly-eye lens 3, and the polarization conversion element 4 are viewed from the side. In the present embodiment, the lights emitted from the respective lens units of the second fly-eye lens 3 and superimposed on each other are rotated by 90 degrees and projected onto the screen. Therefore, the height direction when the first fly-eye lens 2, the second fly-eye lens 3, and the polarization conversion element 4 are viewed from the side is the X direction.

As shown in fig. 2, in the first fly-eye lens 2, for example, 8 lens units 201 (first lens units) are arranged in the X direction. The lens unit 201 is a convex lens, and is not decentered. The 8 lens units 201 have the same height. In the second fly- eye lens 3, 8 lens units 301 (second lens units) are arranged in the X direction corresponding to the respective lens units 201. The lens unit 301 is a convex lens, decentered in the X direction.

Specifically, the lens unit 301 located above the center in the X direction indicated by the one-dot chain line is decentered downward, and the lens unit 301 located below the center is decentered upward. That is, the lens unit 301 located above and the lens unit 301 located below are eccentric to each other toward the center side in the X direction. The degree of decentering of the lens unit 301 becomes larger as the end portion faces upward or downward from the center. The 8 lens units 301 have the same height.

The lower end of the surface of each lens unit 301 of the plurality of lens units 301 arranged in the X direction is denoted by 301a, and the upper end thereof is denoted by 301 b. The end portions 301a and 301b of the two lens units 301 adjacent to each other in the X direction do not coincide with each other, and are shifted in the thickness direction of the second fly-eye lens 3. That is, there is a step on the boundary of the adjacent two lens units 301. Further, there is no step on the boundary between the two lens units 301 sandwiching the center in the X direction shown by the one-dot chain line.

Fig. 3 shows a state in which the first fly-eye lens 2, the second fly-eye lens 3, and the polarization conversion element 4 are viewed from above. The width direction when the first fly-eye lens 2, the second fly-eye lens 3, and the polarization conversion element 4 are viewed from above is the Y direction.

As shown in fig. 3, in the first fly-eye lens 2, for example, 14 lens units 201 are arranged in the Y direction. In the second fly- eye lens 3, 14 lens units 301 are arranged in the Y direction corresponding to the respective lens units 201. The lens unit 301 is decentered in the Y direction.

Specifically, the lens unit 301 located on one side (upper side in fig. 3) with respect to the center in the Y direction shown by the one-dot chain line is decentered to the other side (lower side in fig. 3), and the lens unit 301 located on the other side (lower side in fig. 3) with respect to the center is decentered to one side (upper side in fig. 3). That is, the lens unit 301 on one side and the lens unit 301 on the other side are eccentric to each other toward the center in the Y direction. The degree of decentering of the lens unit 301 becomes larger as going from the center toward the end in the Y direction. The 14 lens units 301 are higher in height in order from the end in the Y direction toward the center.

The lower end of the surface of each lens unit 301 of the plurality of lens units 301 arranged in the Y direction in fig. 3 is denoted as 301c, and the upper end is denoted as 301 d. End portions 301c and 301d of two lens units 301 adjacent to each other in the Y direction coincide with each other, and are not shifted in the thickness direction of the second fly-eye lens 3. That is, in the Y direction, there is no step on the boundary of the adjacent two lens units 301.

Returning to fig. 2, inside the polarization conversion element 4, a reflection surface 41 indicated by a solid line and a polarization separation surface 42 indicated by a broken line are alternately formed in the X direction. The reflection surface 41 and the polarization separation surface 42 are formed to have a predetermined angle with respect to the light incident surface of the polarization conversion element 4. The predetermined angle is preferably 45 degrees. In the present embodiment, the reflecting surface 41 reflects the incident light, and the polarization splitting surface 42 transmits the P-polarized light and reflects the S-polarized light.

Regions sandwiched between the reflection surface 41 and the polarization separation surface 42 are referred to as regions 43 and 44. The distance in the X direction between the region 43 and the region 44 is the same. The size of each lens unit 301 in the X direction is the same as the distance in the X direction after the region 43 and the region 44 are combined. An 1/2 wavelength plate 45 is attached to a part of each region 44 on the light exit surface of the polarization conversion element 4. 1/2 the distance in the X direction of the wavelength plate 45 is 1/2 which is the size of the lens unit 301 in the X direction.

An 1/2 wavelength plate 45 is attached to a part of each region 44 on the light exit surface of the polarization conversion element 4, and the region 44 is referred to as a polarization conversion region 44. The 1/2 wavelength plate 45 is not attached to the part of each region 43 on the light exit surface of the polarization conversion element 4, and the region 43 is referred to as a non-polarization conversion region 43. In the polarization conversion element 4, the unpolarized light conversion regions 43 and the polarized light conversion regions 44 are alternately formed in the X direction at intervals of 1/2, which is the size of the lens cell 301 in the X direction.

Fig. 4 shows a state where the second fly-eye lens 3 and the polarization conversion element 4 are viewed from the second fly-eye lens 3 side. The positions of the non-polarization conversion regions 43 and the polarization conversion regions 44 of the polarization conversion element 4 in fig. 4 show the positions on the emission surface of the polarization conversion element 4. 1/2 the wavelength plate 45 faces the plurality of lens units 301 aligned in the Y direction.

In fig. 4, the boundaries between two adjacent lens units 301 in the X direction, i.e., the end portions 301a and 301b, are stepped, and the stepped state is indicated by a thick solid line. The steps of the boundary shown by the thick solid line are opposed to the unpolarized-light converting region 43 to which the 1/2 wavelength plate 45 is not attached. On the other hand, the boundary between two lens units 301 adjacent to each other in the Y direction, that is, the end portions 301c and 301d, do not form a step and intersect the 1/2 wavelength plate 45.

The operation of the polarization conversion element 4 will be described with reference to fig. 5. In fig. 5, a partial light flux including P-polarized light and S-polarized light emitted from each lens cell 201 of the first fly-eye lens 2 is incident on each lens cell 301 of the second fly-eye lens 3. The light incident on the lens cell 301 is considered to be divided into a central light L1 transmitted through the central portion of the lens cell 301 in the X direction and a peripheral light L2 transmitted through the peripheral portion in the vicinity of the boundary.

What ranges in the X direction of the lens unit 301 are the central portion and what ranges are the peripheral portions can be taken as matters to be determined.

As shown in fig. 5, of the P-polarized light and the S-polarized light included in the central light L1, the P-polarized light passes through the polarization separation surface 42 and enters the 1/2 wavelength plate 45. Since the 1/2 wavelength plate 45 converts P-polarized light into S-polarized light, S-polarized light is emitted from the polarization conversion region 44. Of the P-polarized light and the S-polarized light included in the central light L1, the S-polarized light is reflected by the polarization splitting surface 42 and the traveling direction is bent by 90 degrees, and further, reflected by the reflection surface 41 and the traveling direction is bent by 90 degrees, and is emitted from the unpolarized light conversion region 43.

The P-polarized light and the S-polarized light included in the ambient light L2 are reflected by the reflection surface 41, have traveling directions bent by 90 degrees, and are incident on the polarization separation surface 42. Of the P-polarized light and the S-polarized light incident on the polarization separation surface 42, the P-polarized light transmits through the polarization separation surface 42 and is incident on the other reflection surface 41. The other reflection surface 41 is the next reflection surface 41 on which the P-polarized light transmitted through the polarization splitting surface 42 is incident. The P-polarized light incident on the reflection surface 41 is reflected by the reflection surface 41, and the traveling direction is bent by 90 degrees, and is emitted from the unpolarized light conversion region 43.

The P-polarized light and the S-polarized light of the polarized light incident on polarization splitting surface 42 are reflected by polarization splitting surface 42, have traveling directions bent by 90 degrees, and are incident on 1/2 wavelength plate 45. Since the 1/2 wavelength plate 45 converts S-polarized light into P-polarized light, P-polarized light is emitted from the polarization conversion region 44.

As described above, the second fly-eye lens 3 has a step at the boundary (first boundary) between two adjacent lens units 301 in the X direction, but has no step at the boundary (second boundary) between two adjacent lens units 301 in the Y direction. Since steps are eliminated only at the boundaries of the lens units 301 adjacent in the Y direction, variations in the size of the illumination range of each lens unit 301 can be minimized.

Therefore, the size of the illumination range of each lens unit 301 is hardly changed from the size of the illumination range in the shape having a step at the boundary between the X direction and the Y direction, and the luminance of the light emitted from each lens unit 301 and superimposed is hardly uniform in the plane.

As described with reference to fig. 5, the polarization conversion element 4 emits the P-polarized light based on the peripheral light L2 transmitted through the peripheral portion near the boundary of the lens cell 301 in the X direction. However, since P-polarized light is not used as illumination light, even if there is a shape error of "slack" or "notch" at the end of the lens unit 301, the quality of an image projected onto a screen is not adversely affected.

As shown in fig. 4, the boundary of the lens unit 301 in the Y direction faces the 1/2 wavelength plate 45 so as to intersect with it, but there is no step at the boundary of the lens unit 301 adjacent in the Y direction. Therefore, the peripheral light passing through the peripheral portion near the boundary of the lens unit 301 in the Y direction does not adversely affect the quality of the image projected onto the screen.

In the present embodiment, the plurality of lens units 301 are decentered in both the X direction and the Y direction so that the partial light fluxes emitted from the respective lens units 301 overlap each other. Therefore, the projection type image display apparatus 100 does not need the condenser lens 5 for overlapping the respective partial light fluxes at the subsequent stage of the polarization conversion element 4. By omitting the condenser lens 5, the number of components can be reduced, and the brightness is not reduced by the light passing through the condenser lens 5.

The present invention is not limited to the embodiment described above, and various modifications can be made without departing from the scope of the present invention. The projection type image display apparatus of the present invention is not particularly limited as long as it includes a pair of fly eye lenses and a polarization conversion element, and the configuration of the rear stage of the polarization conversion element is not particularly limited.

Description of the symbols

1 … light source;

2 … first fly-eye lens;

3 … second fly-eye lens;

4 … polarization conversion element;

41 … reflective surface;

42 … polarization splitting surface

43 … a non-polarized light conversion region;

44 … polarized light conversion region;

45 … 1/2 wavelength plates;

201. 301 … lens cell;

301a, 301b, 301c, 301d ….