We prove the reducibility of 1D quantum harmonic oscillators in
R
perturbed by a quasi-periodic in time potential V(x, ωt) under the following conditions, namely there is a C > 0 such that
|
V
(
x
,
θ
)
|
⩽
C
,
|
x
∂
x
V
(
x
,
θ
)
|
⩽
C
,
∀
(
x
,
θ
)
∈
R
×
T
σ
n
. The corresponding perturbation matrix
(
P
i
j
(
θ
)
)
is proved to satisfy
(
1
+
|
i
−
j
|
)
|
P
i
j
(
θ
)
|
⩽
C
and
i
j
|
P
i
+
1
j
+
1
(
θ
)
−
P
i
j
(
θ
)
|
⩽
C
for any
θ
∈
T
σ
n
and i, j ⩾ 1. A new reducibility theorem is set up under this kind of decay in the perturbation matrix element
P
i
j
(
θ
)
as well as the discrete difference matrix element
P
i
+
1
j
+
1
(
θ
)
−
P
i
j
(
θ
)
. For the proof the novelty is that we use the decay in the discrete difference matrix element to control the measure estimates for the thrown parameter sets.