I think you mean "the difference between public security and police"? Tell you the origin and changes of these two words.
"Police" was originally a verb, meaning "warning beforehand and observing afterwards". There is a passage in Hanshu that "the messenger police are unwilling to make it public", which is what the "police" here means.
After the Revolution of 1911, in 19 12, the domestic governor and policeman (founded by Yuan Shikai) were renamed as "police". Since then, "police" has become a noun, referring to the armed forces and staff who maintain public order and social order (this concept is different from the current situation in Chinese mainland).
1927, Chiang Kai-shek renamed the police organs of various provinces, cities and counties in China as "Public Security Bureau", and the word "public security" appeared in China. Although the name of the organization has changed, the name of the staff has not changed, and it is still called "police".
The term "public safety" originated from the "Public Safety Committee" during the French Revolution, not from China, nor is it a patent of CCP. South Korea, Japan, Vietnam, Israel and other countries all have public security institutions.
1938, the current regime established the people's police force in the Shaanxi-Gansu-Ningxia border region, referred to as "border police", and renamed it "public security organ" the following year. People's public security appeared in China, and CCP police were called "public security personnel".
It is said that this is to play a role in distinguishing the "reactionary police" of the National Government.
For a long time, the public security organs were responsible for all police functions in China. Although the word "people's police" has appeared, its influence is far less extensive than that of "public security". So many people think that there is no police in our country, which is not surprising, because public security and police at that time were completely the same thing.
In the 1980s, many departments of the public security system were separated from the Ministry of Public Security. For example, two labor departments merged into the Ministry of Justice to become a prison reeducation-through-labor system, and the anti-labor department merged with the entire Central Coordination Department, the United Front Work Department and some units of the Science, Technology and Industry Committee for National Defense to form the Ministry of National Security. There are five police systems in China, and the public security system is just one of them.
But many people don't understand this and still think that public security and police are equal.
As for the reason why you think "when did the police become popular in China", it depends on the change of police composition and uniform style.
The police in our country are divided into five systems, namely, public security system, national security system, prison reeducation through labor system (the three are people's policemen who exercise administrative law enforcement power and part of judicial power, referred to as "police"), court bailiffs and procuratorate bailiffs (both are judicial policemen who exercise judicial power but have no law enforcement power, referred to as "bailiffs").
The words on the 92-type police armband distinguish five police systems: the public security system is the public security police, the national security system is the national security police, the prison reeducation-through-labor system is the police SIFA, and the court is the bailiff.
This difference is already obvious and everyone is aware of it. However, because the national security police and the bailiffs of the two academies are relatively rare, they usually see police and prison police (much less than prison guards), so many people actually notice the difference between police armbands and prison armbands, so there is the question "What is the difference between public security and police?" The most classic answer is "Public security is a very broad concept, and hanging police armbands is a good public security."
In 2000, the police uniform was changed to the current 99-style, and the 99-style armband strengthened the function of showing police identity. The armbands of the five major systems are marked with the word "police" in conspicuous positions on both sides of the five-pointed star, and the system names are marked on the Great Wall pattern in small print; Later, the police car was painted with a new label, and the words "police" were painted on the hoods of all police cars in five systems.
If we want to say "popular", it should start from this period, but it is actually just a kind of popularization.