Apparatus comprising a display screen which is active in the operating mode and in the standby mode

A display apparatus includes the switching unit for switching between an operating mode and a standby mode. The apparatus generates a picture on a display screen in the standby mode. The apparatus includes, for example a microphone for measuring a sound volume in the vicinity of the apparatus. The microphone is coupled to the picture-generating unit in order to change the picture in the standby mode in response to a change of the measured sound volume.

This invention relates to an apparatus which includes switching means for 
switching the apparatus between an operating mode and a standby mode, a 
display screen, and a picture generating unit for generating a picture on 
the display screen in the standby mode. 
BACKGROUND OF THE INVENTION 
When the apparatus is a PC (Personal Computer) operating on the basis of 
the Microsoft.RTM. Windows.RTM. program, for example, it is known to 
switch over from the operating mode to a standby mode if no operations are 
to be executed via the keyboard for a time interval of predetermined 
duration. The standby mode is in that case a so-called "screen saving" 
mode in which the picture is, for example, darkened or changes in the 
course of time in order to prevent burning in of the display screen. 
SUMMARY OF THE INVENTION 
It is, inter alia, an object of the invention to provide an apparatus which 
is more attractive to the consumer in the standby mode and which provides 
an alternative method of changing the picture. 
The apparatus in accordance with the invention includes measuring means for 
measuring a value of a parameter of an environment of the apparatus, 
coupled to the picture-generating means, in order to change a picture 
composition in the standby mode in response to a change of the measured 
value. The parameter of the environment is preferably chosen so that the 
user of the apparatus can directly influence this parameter independently 
of any user operable input devices for the apparatus; (by way of normal 
physical expressions which are not specifically aimed at control members 
for the operating mode of the apparatus). This concerns more than changes 
due exclusively to the elapse of time. Thus, the apparatus is prevented 
from monotonously displaying the same picture in the standby mode. The 
user can knowingly or unknowingly induce a change of the composition of 
the picture while the apparatus remains in the standby mode. 
In one embodiment of the apparatus in, the parameter is a sound signal. 
Notably a sound signal can be simply influenced by the user in a variety 
of ways, so that a variety of changes of the picture composition are 
possible in response thereto. 
An embodiment of the apparatus in accordance with the invention is 
characterized in that the measuring means are arranged to measure at least 
one of the following properties of the sound signal: 
a volume 
a pitch 
a frequency at which maxima occur in the volume, 
and that the picture-generating means are arranged to change the picture 
composition in response to a change of at least one of said properties. 
Other feasible parameters are for example an ambient temperature, an 
ambient light intensity, a spectral composition of the ambient light, etc. 
An embodiment of the apparatus in accordance with the invention is 
characterized in that the measuring means are arranged to measure at least 
two of said properties of the sound signal, and that picture-generating 
means are arranged to induce a unique, respective change of the picture 
composition in response to a change of each of the measured properties. By 
coupling a unique type of response to each type of change, a varied 
picture change is achieved. 
An embodiment of the apparatus in accordance with the invention is 
characterized in that the picture-generating means are arranged to change 
at least one of the following picture characteristics in response to the 
change of the measured value: 
a colour contents 
a size of objects displayed 
a number of objects displayed. 
For example, a change of size can be coupled to a change of sound volume, a 
change of colour can be coupled to a change of frequency, and another 
change can be coupled to a change of pitch. Other combinations, however, 
are also feasible. The user himself may even be allowed to adjust the 
combinations to be used. 
The invention is particularly suitable for use in a television receiver; 
this receiver will usually be switched between the operating mode and the 
standby mode by the user. The invention, however, can also be used in 
other apparatus, not only for screen saving purposes but also for energy 
saving purposes when a part of the apparatus which is normally supplied 
with energy in the operating mode is not supplied with energy or with less 
energy, in the standby mode. Generally speaking, in the standby mode an 
essential part of the apparatus, for example, the receiving section, is 
substantially inactive in the function for which it is provided (for 
example, supplying the display screen with supplied information and/or 
information explicitly selected by the user).

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
FIG. 1 shows, by way of example, an apparatus 1 in the form of a television 
receiver. The receiver includes a receiving and decoding section 10 with 
an input and an output. The receiver 1 also includes a microphone 15 which 
is coupled to a measuring unit 16 which itself is coupled to 
picture-generating means 17. The output of the picture-generating means 17 
and that of the receiving and decoding section 10 are coupled to a switch 
12 which optionally connects one of the two outputs to picture display 
means 14. The picture display means includes a display screen 18. The 
switch 12 is controlled by a control unit 13. 
During operation, the control unit 13 receives switching commands, for 
example from a remote control, in response to which the control unit 13 
can switch the switch 12 to and fro between a first position, in which the 
output of the receiving and decoding section 10 is coupled to the picture 
display means 14, and a second position in which the output of the 
picture-generating means 17 is coupled to the picture display means 14. 
The first position corresponds to the operating mode of the apparatus 1 
whereas the second position corresponds to the standby mode. 
In the operating mode the apparatus acts as a television receiver and the 
display means 14 display, on the display screen 18, video signals received 
on the input of the receiving and decoding unit 10 (for example, from an 
aerial, a cable television connection, or a video recorder, etc.). 
In the standby mode the display means 14 display a picture on the display 
screen 18 which has been generated by the picture-generating means 17. The 
picture-generating means 17 comprise, for example, a processor (not shown) 
which executes a graphics program so as to generate the picture. The 
graphics program provides, for example, a picture which comprises a number 
of circular discs of different colour, diameter and position. 
The microphone 15 picks up sound from the environment of the apparatus 1 
and hence forms a signal which is applied to the measuring unit 16. The 
measuring unit determines a number of properties of this signal, for 
example the volume (the amplitude of the signal averaged over a 
predetermined period of, for example 1 second), the pitch (for example, 
the period duration between successive zero crossings of the signal), and 
the peak frequency, i.e. the inverse of the distance in time between 
instants at which maxima occur in the volume as a function of time. 
The measured values of these properties are applied to the 
picture-generating means 17 which generate the picture in dependence on 
the measured values. 
FIG. 2 shows an example of a composition of a picture 20. For example, each 
time when a peak occurs in the sound signal, the picture-generating means 
17 add to the picture 20 a circular disc 22a-d of a size which is 
proportional to the sound volume and of a colour of a wavelength which is 
proportional to the pitch. A circular disc is omitted again some time 
after having been generated. 
It will be evident that this picture 20 is given merely by way of example 
and that numerous other types of pictures are feasible which can all be 
made dependent on the measured properties of the sound signal. For 
example, instead of using graphically generated pictures of circular 
segments, use can be made of a graphics system which executes graphic 
commands which result in a generated picture, the graphics commands (for 
example, outline descriptions as in the language Postscript.RTM. by 
Adobe.RTM., or graphics commands such as are available within Windows.RTM. 
by Microsoft.RTM.), being stored in advance in a memory and being 
supplemented in dependence on the properties of the sound signal (for 
example with position, colour, rotation or scale commands). 
Furthermore, use can be made of a sprite (a bit map of a partial image 
representing an object) which is stored in a memory, for example a sprite 
of an animal. For generating the contents of this sprite are then 
reproduced in the image. Examples of selectable image characteristics are 
then the choice between different sprites stored in the memory (for 
example, of different animals), the size of display, colour, speed, 
direction and path of movements in the image, in dependence on the 
measured value of the parameter of the environment, for example the sound 
signal. Use can also be made of pictures of landscapes, as a background, 
or to introduce changes (seasonal effects, weather conditions, etc.), in 
dependence on the measured value of the parameter of the environment. 
Numerous other possibilities also exist. 
Preferably, the changes in the composition of the picture concern 
incremental changes, which means that not each time a new picture is 
generated whose composition is not related to the previous picture, but 
that the picture is only partly changed each time. 
The pictures and the way in which they depend on the parameters of the 
environment can also be automatically changed by the apparatus in the 
course of time (for example, after a period of hours or weeks), or be 
changed by the user. Thus, the type of sprite or the relationship between 
the picture characteristics and the properties of the parameter of the 
environment can be made variable. 
Even though the invention is notably suitable for television receivers and 
monitors for picture reproduction apparatus, and has also been described 
in this context, it can also be used for other equipment such as personal 
computers. Instead of the microphone 15 for measuring a sound signal, 
other types of sensor can be used, for example, sensors for measuring 
other parameters of the environment, such as temperature, ambient light, 
motions in the environment etc. Such sensors can also be used in 
combination or together with a microphone so as to initiate a respective 
unique change in the picture.