Back projection-type screen and back projection-type projection device
AssigneeKuraray Co., Ltd.
InventorYouji Ono
Life of this patent
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Abstract
A rear projection-type screen and a rear projection-type projection device, in which contrast is enhanced, unevenness of an external light absorption layer is reduced, moiré trouble is suppressed, damage due to contact between sheets is suppressed, and the entire projection device can be reduced in size and weight. The rear projection-type screen is the so-called oblique projection system where the optical center of a Fresnel lens sheet 7 is located at a position outside a display screen area, above or below the screen. The lens array 12 of a lenticular lens sheet 1 is arranged substantially in the vertical direction. Moiré can be reduced by setting the pitch of Fresnel lens and the lens pitch of the lenticular lens sheet within a predetermined range.
Claims16
A rear projection-type screen comprising:
- a Fresnel lens sheet for narrowing light emitted from a rear projection-type projector to a certain range of angle;
- and
- a light diffusion sheet including a plurality of at least substantially vertically and linearly successive optical patterns arranged in substantially horizontal direction,
- wherein an optical center of the Fresnel lens sheet is located outside a display screen area, above or below the screen, and
- any one of following equations (1) to (3) is satisfied:
- P
-
-
- 1
- Pf
- =
- i
- +
- 0.0
- ~
- 0.35
-
-
- or
-
-
- P
-
-
- 1
- Pf
- =
- 1
- i
- +
- 0.0
- ~
- 0.35
- (
- 1
- )
- P
-
-
- 1
- Pf
- =
- i
- +
- 0.45
- ~
- 0.55
-
-
- or
-
-
- P
-
-
- 1
- Pf
- =
- 1
- i
- +
- 0.45
- ~
- 0.55
- (
- 2
- )
- P
-
-
- 1
- Pf
- =
- i
- +
- 0.65
- ~
- 1.0
-
-
- or
-
-
- P
-
-
- 1
- Pf
- =
- 1
- i
- +
- 0.65
- ~
- 1.0
- (
- 3
- )
- where i represents a natural number of 12 or less, Pf(mm) represents a pitch of the Fresnel lens, and P1(mm) represents a pitch of the optical patterns of the light diffusion sheet.
A rear projection-type screen comprising:
- a Fresnel lens sheet for narrowing light emitted from a rear projection-type projector to a certain range of angle;
- and
- a microlens array sheet including a microlens array placed on a light incident surface to diffuse light in substantially horizontal and vertical directions, and a self-aligned external light absorbing layer placed on at least part of a non-transmission portion of light transmitted through the microlens array,
- wherein an optical center of the Fresnel lens sheet is located outside a display screen area, above or below the screen,
- the Fresnel lens sheet and the microlens array sheet satisfy any one of following equations (1*) to (3*), and
- the Fresnel lens sheet and the microlens array sheet satisfy either one of following equations (4*) and (5*) and further satisfy a following equation (6*):
- P
-
-
- 1
- *
- Pf
- =
- i
- +
- 0.0
- ~
- 0.35
-
-
- or
-
-
- P
-
-
- 1
- *
- Pf
- =
- 1
- i
- +
- 0.0
- ~
- 0.35
- (
- 1
- *
- )
- P
-
-
- 1
- *
- Pf
- =
- i
- +
- 0.45`
- ~
- 0.55
-
-
- or
-
-
- P
-
-
- 1
- *
- Pf
- =
- 1
- i
- +
- 0.45
- ~
- 0.55
- (
- 2
- *
- )
- P
-
-
- 1
- *
- Pf
- =
- i
- +
- 0.65
- ~
- 1.0
-
-
- or
-
-
- P
-
-
- 1
- *
- Pf
- =
- 1
- i
- +
- 0.65
- ~
- 1.0
- (
- 3
- *
- )
- where i represents a natural number of 12 or smaller, Pf(mm) represents a pitch of the Fresnel lens, and P1*(nm) represents an effective pitch of the microlens array in substantially horizontal direction,
- P
-
-
- 2
- *
- Pf
- =
- i
- +
- 0.35
- ~
- 0.45
-
-
- or
-
-
- P
-
-
- 2
- *
- Pf
- =
- 1
- i
- +
- 0.35
- ~
- 0.45
- (
- 4
- *
- )
- P
-
-
- 2
- *
- Pf
- =
- i
- +
- 0.55
- ~
- 0.65
-
-
- or
-
-
- P
-
-
- 2
- *
- Pf
- =
- 1
- i
- +
- 0.55
- ~
- 0.65
- (
- 5
- *
- )
- PM
- *
- =
- 1
-
- 1
- P
- *
- -
- 1
- Pf
-
- ≤
- 3
-
-
- (
- mm
- )
- (
- 6
- *
- )
- where i represents a natural number of 12 or smaller, an effective pitch of a microlens array in substantially vertical direction is P2*(mm), a pitch of a lattice by P1* and P2* in a screen diagonal direction is P*(mm) that is calculated from a following equation (7*), a pitch of a moiré pattern due to P* and Pf is PM*(mm), and n and m represent natural numbers or 4 or smaller,
- P
- *
- =
- 1
- 1
- n
- 2
-
- P
-
-
- 1
- *
- 2
- +
- 1
- m
- 2
-
- P
-
-
- 2
- *
- 2
- .
- (
- 7
- *
- )
Dependencies are inferred from the claim text.