Optical element suitable for projection display apparatus

Claim 2

An optical element according to claim 1, wherein said reflecting film (332) is a dielectric multi-layer film.

Claim 3

An optical element according to claim 1 or 2, further comprising polarization direction converting means (381) associated with either of said first exit surface and said second exit surface.

Claim 4

An optical element according to claim 1, 2 or 3 further comprising light shielding means associated with said second incident surface.

Claim 5

An optical element according to any preceding claim, further comprising adhesive layers (325) between said first (321) and second (322) transparent members, and wherein at least one of a thickness of the adhesive layers (325) and thicknesses of said first (321) and second (322) transparent members are adjusted to make intervals between said polarization splitting films (331) and said reflecting films (332) substantially constant throughout the optical element.

Claim 6

An optical element according to claim 5, wherein the thickness of said second transparent members (322) is set smaller than the thickness of said first transparent members (321) .

Claim 7

An optical element according to claim 6, wherein the thickness of said second transparent members (322) is in the range of 80% to 90% of the thickness of said first transparent members (321).

Claim 8

An optical element according to claim 5, wherein the thickness of said first transparent members (321) is equal to a value obtained by adding twice the thickness of said adhesive layers (325) to the thickness of said second transparent members (322).

Claim 9

An optical element according to claim 1, wherein said optical element is to be used with a plurality of small lenses (311) which will be arranged on said incident plane, and the intervals between said plurality of polarization splitting films (331) substantially correspond to a pitch of the plurality of small lenses (311).

Claim 10

An optical element according to claim 9, further comprising adhesive layers (325) between said first (321) and second (322) transparent members, and wherein at least one of a thickness of the adhesive layers (325) and thicknesses of said first (321) and second (322) transparent members are adjusted to make the intervals between said plurality of polarization splitting films (331) substantially correspond to a pitch of an optical axes of the plurality of small lenses (311).

Claim 11

An optical element according to claim 10, wherein the plurality of small lenses (311) have a plurality of different optical axis pitches, and at least one of the thickness of the adhesive layers (325) and the thicknesses of said first (321) and second (322) transparent members are adjusted to make the intervals between said plurality of polarization splitting films substantially correspond to the plurality of different optical axis pitches.

Claim 12

An optical element according to claim 1, wherein said optical element is to be used with a plurality of small lenses (311) which will be arranged on said incident plane, and intervals between said plurality of polarization splitting films (331) substantially correspond to a pitch of a plurality of light beams exiting from the plurality of small lenses (311) .

Claim 13

An optical element according to claim 12, further comprising adhesive layers (325) between said first (321) and second (322) transparent members, and at least one of the thickness of the adhesive layers (325) and the thicknesses of said first (321) and second (322) transparent members are adjusted to make the intervals between said plurality of polarization splitting films (331) substantially correspond to the pitch of the plurality of light beams exiting from the plurality of small lenses (311) .

Claim 15

A method for producing an optical element according to claim 14, further comprising the step of: (f) polishing said incident plane and said exit plane of the optical element block.

Claim 16

A method for producing an optical element according to claim 14 or 15, wherein said step (d) comprises the steps of: alternately stacking said plurality of first transparent members (321) and said plurality of second transparent members (322) with layers of photocuring adhesive (325) therebetween; and adhering the stacked first (321) and second (322) transparent members through exposure of light.

Claim 17

A method for producing an optical element according to claim 14 or 15, wherein said step (d) comprises the steps of: (1) forming a stack by stacking one of said plurality of first transparent members (321) and one of said plurality of second transparent members (322) with a layer of photo-curing adhesive (325) therebetween; (2) curing said photo-curing adhesive layer (325) by irradiating the stack with light; and (3) alternately stacking one of said plurality of first transparent members (321) and one of said plurality of second transparent members (322) on said stack with layers of the photo-curing adhesive (325) therebetween, respectively, while curing the individual photo-curing adhesive layers (325) by irradiating the stack with light each time one transparent member is added.

Claim 18

A method for producing an optical element according to claim 14 or 15, wherein said step (d) comprises the steps of: (1) forming a stack by stacking one of said plurality of first transparent members (321) and one of said plurality of second transparent members (322) with a layer of photo-curing adhesive (325) therebetween, (2) curing said photo-curing adhesive layer (325) by irradiating the stack with light to produce a unit stack, and (3) stacking a plurality of unit stacks obtained by said steps (1) and (2) with layers of the photo-curing adhesive (325) therebetween, respectively, while curing the individual photo-curing adhesive layers (325) by irradiating a stack of said unit stacks with light each time one unit stack is added.

Claim 19

A method for producing an optical element according to claim 16, wherein the irradiation is conducted in a direction not parallel to the surfaces of the transparent members (321, 322).

Claim 20

A projection display apparatus (800) comprising an optical element comprising: a plurality of first transparent members (321) each having a first incident surface and a first exit surface substantially parallel to each other, first and second film forming surfaces substantially parallel to each other and making a prescribed angle with said first incident surface and said first exit surface, a polarization splitting film (331) formed on said first film forming surface, and a reflecting film (332) formed on said second film forming surface; and a plurality of second transparent members (322) each having a second incident surface and a second exit surface parallel to each other, said plurality of second transparent members (322) being alternately arranged with and secured to said plurality of first transparent members (321) at said first and second film forming surfaces across said polarization splitting film (331) and said reflecting film (332) respectively so that said second incident surfaces are aligned with said first incident surfaces to form an incident plane and that said second exit surfaces are aligned with said first exit surfaces to form an exit plane; polarization converting means (380) for converting light exiting from said optical element to one type of polarized light; modulating means (803, 805, 811) for modulating the light exiting said polarization converting means (380) as a function of a given image signal; and a projection optical system (814) for projecting the light modulated by said modulating means (803, 805, 811) on a screen (815).

Claim 21

An optical element comprising: a plurality of polarization splitting members, each comprising: a light incident surface; a light exit surface substantially parallel to said light incident surface; a polarization splitting film (331) formed at a prescribed angle with said light incident surface and said light exit surface; and a reflecting film (332) substantially parallel to said polarization splitting film (331); wherein said plurality of polarization splitting members are arranged in a form of a matrix, and said polarization splitting film (331) and said reflecting film (332) are a dielectric multi-layer film.

Claim 22

An optical element according to claim 21, wherein said light exit surface includes a first exit surface portion and a second exit surface portion, said first exit surface portion emitting selected one of S-polarized light and P-polarized light which has passed through said polarization splitting film (331), said second exit surface portion emitting the other one of the S-polarized light and P-polarized light which has been reflected by said polarization splitting film (331) and said reflecting film (332), and said optical element further comprises a λ/2 phase plate (381) associated with selected one of said first and second exit surface portions.

Claim 23

A projection display apparatus (800) comprising: a light source (10) for generating luminous flux including S-polarized light and P-polarized light; an optical element (300) for receiving the luminous flux from said light source (10) and emitting the luminous flux as selected one of S-polarized light and P-polarized light; modulating means (803, 805, 811) for modulating the light exiting said optical element as a function of a given image signal; and a projection optical system (814) for projecting the light modulated by said modulating means on a screen (815); wherein said optical element (300) comprises: a plurality of polarization splitting members, each comprising: a light incident surface; a light exit surface substantially parallel to said light incident surface; a polarization splitting film (331) formed at a prescribed angle with said light incident surface and said light exit surface; and a reflecting film (332) substantially parallel to said polarization splitting film (331); wherein said plurality of polarization splitting members are arranged in a form of a matrix, and said polarization splitting film (331) and said reflecting film (332) are a dielectric multi-layer film.