Eyepiece lens and display unit
An eyepiece lens includes: a first lens having positive refractive power, the first lens having a convex surface that faces toward an eye point side; and a second lens having positive refractive power, the second lens having a convex surface that faces toward the eye point side. The first and second lenses are arranged in order from the eye point side. Following conditional expressions are satisfied, 3.0>( h ×ω) 1/2 /E >1.2 (1) 2.3>( L−E )/ h >1.5 (2) where h is a height of the image at a horizontal end, ω is a half angle of view in a horizontal direction, E is a distance from an eye point to the first lens, the distance being an eye relief, and L is a distance from the eye point to the image.
1. An eyepiece lens comprising:
a first lens having positive refractive power, the first lens having a convex surface that faces toward an eye point side; and
a second lens having positive refractive power, the second lens having a convex surface that faces toward the eye point side,
the first and second lenses being arranged in order from the eye point side, wherein
following conditional expressions are satisfied,
3.0>( h ×ω) 1/2 /E> 1.2 (1)
2.3>( L−E )/ h> 1.5 (2)
where h is a height of an image at a horizontal end,
ω is a half angle of view in a horizontal direction,
E is a distance from an eye point to the first lens, the distance being an eye relief, and
L is a distance from the eye point to the image.
2. The eyepiece lens according to claim 1 , wherein a following conditional expression is satisfied,
3.7>( f 1 ×f 2) 1/2 /f> 1.4 (3)
where f is a total focal length,
f1 is a focal length of the first lens, and
f2 is a focal length of the second lens.
3. The eyepiece lens according to claim 1 , wherein a following conditional expression is satisfied,
40>|( R 3 +R 5)/( R 3 −R 5)| (4)
where R3 is a paraxial curvature radius of an image-sided surface of the first lens, and
R5 is a paraxial curvature radius of an image-sided surface of the second lens.
4. The eyepiece lens according to claim 1 , wherein a following conditional expression is satisfied,
1.9 >R 4 /f 2>0.4 (5)
where R4 is a paraxial curvature radius of the eye-point-sided surface of the second lens.
5. The eyepiece lens according to claim 1 , wherein a following conditional expression is satisfied,
1.0 >R 2 /f 1>0.1 (6)
where R2 is a paraxial curvature radius of the eye-point-sided surface of the first lens.
6. The eyepiece lens according to claim 1 , wherein a following conditional expression is satisfied, wherein
1.2>( D 2 +D 4)/( D 3 +D 5)>0.2 (7)
wherein D2 is a central thickness of the first lens,
D3 is a spacing between the first lens and the second lens,
D4 is a central thickness of the second lens, and
D5 is a spacing between the second lens and the image.
7. The eyepiece lens according to claim 1 , wherein an image-sided surface of the first lens and an image-sided surface of the second lens each have an aspherical shape.
8. The eyepiece lens according to claim 1 , wherein the eye-point-sided surface of the first lens has an aspherical shape that has an inflection point.
9. The eyepiece lens according to claim 1 , wherein the first and second lenses are each configured of a material having a linear expansion coefficient of 20×10 −6 /° C. or larger.
10. A display unit comprising:
an image display device; and
an eyepiece lens configured to allow an image displayed on the image display device to be magnified,
the eyepiece lens including
a first lens having positive refractive power, the first lens having a convex surface that faces toward an eye point side, and
a second lens having positive refractive power, the second lens having a convex surface that faces toward the eye point side,
the first and second lenses being arranged in order from the eye point side, wherein
following conditional expressions are satisfied,
3.0>( h ×ω) 1/2 /E> 1.2 (1)
2.3>( L−E )/ h> 1.5 (2)
where h is a height of the image at a horizontal end,
ω is a half angle of view in a horizontal direction,
E is a distance from an eye point to the first lens, the distance being an eye relief, and
L is a distance from the eye point to the image.