Patent ID: 7120094

Claim:
A device for reading and/or writing information from/onto an optical information carrier; said information stored in the form of differences in intensity level, said device comprising: read means including imaging means for imaging a radiation beam so as to form a scanning spot by means of which the information carrier is scanned, including detection means for generating a read signal which is indicative of the intensity of the radiation reflected from the information carrier at the location of the scanning spot; which device has an information transfer mode, in which the scanning spot is moved in a first direction with respect to the information carrier; which device has a displacement mode, in which the scanning spot is moved in a second direction transverse to the first direction; control means for controlling the imaging means in response to a measurement signal which is indicative of the degree of focusing of the radiation beam at the location of the scanning spot, which control means include sample and hold means for sampling and holding the measurement signal in response to a sample signal, wherein the sample signal (S CNTRL ) causes the measurement signal to be sampled at locations having mutually the same intensity level, and to cause sampling of the measurement signal if the measurement signal has not been measured within a predetermined period of time.