4. (10 points) On the clock tower of a railway station, there is an electronic clock. On the boundary of the circular clock face, there is a small colored light at each minute mark. At 9:37:20 PM, there are $\qquad$ small colored lights within the acute angle formed by the minute and hour hands.
【Analysis】First, analyze the clock face at the hour. When it is 9 o'clock and then it moves 37 minutes and 20 seconds, calculate the distance traveled by the hour hand and the minute hand to find the difference in the number of spaces between them.

【Solution】Solution: According to the problem, we know:
Starting from 9 PM, when the minute hand has moved 37 spaces and 20 seconds, the hour hand has moved $\left(37+\frac{1}{3}\right) \times \frac{1}{12}=3 \frac{1}{9}$; the hour hand has moved more than 3 spaces. The minute hand has moved 37 spaces, so there are 11 spaces between 38 and 48. Therefore, the answer is: 11.