Display device and light-emitting device
A display device includes a control circuit. By setting an intermediate point between a start point and an end point of a lighting period as a start point of the lighting cycle, and setting an intermediate point between a start point and an end point of a lighting period of the next lighting period as an end point of the lighting cycle, the control circuit controls a backlight such that an absolute value of a difference value between a first ratio of a sum of a length of a first lighting period in the first lighting cycle and a length of the next second lighting period in the first lighting cycle to a length of the first lighting cycle and the target duty ratio is 0.1 or less.
1. A display device comprising:
a display panel including a light-emitting member that repeats lighting on and off;
a display control unit configured to control a length of a synchronization cycle that is a cycle of a vertical synchronization signal for driving the display panel; and
a light emitting control unit configured to control a length of a lighting period that is a period during which the light-emitting member lights on and a length of a lighting cycle that is a cycle during which the light-emitting member lights on, the light emitting control unit being configured to control the light-emitting member based on a target duty ratio that is a target value of a ratio of the length of the lighting period to the length of the synchronization cycle, wherein
the light emitting control unit controls the length of the lighting cycle by setting an intermediate point between a start point and an end point of the lighting period as a start point of the lighting cycle, and setting an intermediate point between a start point and an end point of a lighting period of the next lighting period as an end point of the lighting cycle, and
when the length of the lighting cycle is changed from a first lighting cycle to a second lighting cycle, controls the light-emitting member such that an absolute value of a difference value between a first ratio of a sum of a length of a first lighting period in the first lighting cycle and a length of a next second lighting period in the first lighting cycle to a length of the first lighting cycle and the target duty ratio is 0.1 or less, and
controls the light-emitting member such that an absolute value of a difference value controls the light-emitting member such that an absolute value of a difference value between a second ratio of a sum of the length of the next second lighting period in the second lighting cycle and a length of a next third lighting period in the second lighting cycle to a length of the second lighting cycle and the target duty ratio is 0.1 or less.
2. The display device according to claim 1 ,
wherein the display control unit inserts a transition frame between a final frame in which the display panel operates according to a first synchronization cycle and a first frame in which the display panel operates according to a second synchronization cycle when the display control unit changes the length of the synchronization cycle from the first synchronization cycle to the second synchronization cycle, and
the light emitting control unit controls the light-emitting member in synchronization with the vertical synchronization signal,
changes the length of the lighting cycle from the first lighting cycle to the second lighting cycle when the length of the synchronization cycle is changed from the first synchronization cycle to the second synchronization cycle by the display control unit, and
changes the length of the lighting cycle from the first lighting cycle to the second lighting cycle in the transition frame.
3. The display device according to claim 2 ,
wherein the light emitting control unit controls lighting of the light-emitting member in a state where mathematical formulas (1) to (4) are satisfied,
[
Expression
16
]
Tt
>
0
,
Tt
+
Wt
<
Vt
(
1
)
[
Expression
17
]
Wb
2
+
Wt
2
Vb
-
Tb
-
Wb
2
+
Tt
+
Wt
2
=
R
1
(
2
)
[
Expression
18
]
Wt
2
+
Wa
2
Vt
-
Tt
-
Wt
2
+
Ta
+
Wa
2
=
R
2
(
3
)
[
Expression
19
]
❘
"\[LeftBracketingBar]"
R
1
-
D
❘
"\[RightBracketingBar]"
≤
0.1
,
❘
"\[LeftBracketingBar]"
R
2
-
D
❘
"\[RightBracketingBar]"
≤
0.1
(
4
)
where the target duty ratio is D, a length of the first synchronization cycle is Vb, a period from a start point of the first synchronization cycle to a start point of the first lighting period is Tb, the length of the first lighting period is Wb, a length of the transition frame is Vt, a period from a start point of the transition frame to a start point of the next second lighting period is Tt, the length of the next second lighting period is Wt, a length of the second synchronization cycle is Va, a period from a start point of the second synchronization cycle to a start point of the next third lighting period is Ta, and a length of the next third lighting period is Wa.
4. The display device according to claim 2 ,
wherein a length of the transition frame is equal to either a length of the first synchronization cycle or a length of the second synchronization cycle.
5. The display device according to claim 1 ,
wherein the light emitting control unit determines the length of the next second lighting period to be a length between the length of the first lighting period and the length of the next third lighting period.