[0001] The present invention relates to electronic apparatus for controlling the presentation
of a changeable visual display.
[0002] Electronic apparatus for controlling the presentation of a changeable display have
been proposed for use with liquid crystal display digital time-pieces as disclosed
UK Patent No. 1569022 and UK Patent application 2026736 and also for use with a method
for drawing graphic symbols as disclosed in UK Patent application 2028067. However
such apparatus is limited to producing only a temporal alphanumeric display or graphic
symbols. This type of apparatus requires external controls to operate the display.
In addition this type of apparatus cannot be used to produce a temporal visual display
which imitates animated motion, such as showing cartoon characters.
[0003] UK Patent application No. 2037048 discloses an LCD game drawn under the control of
a microprocessor.. Images are produced on the LCD which is composed of a matrix of
LCD elements. With this type of display a 'staircase' is formed by the elements whenever
a diagonal or a curved line is required. This is a poor visual representation compared
with other 2-dimensional representations such as television, photographs and the like.
In addition, this device requires a microprocess6r- to operate and also external controls
to operate the device and change the display.
[0004] The present invention is intended to provide a remedy. It solves the problem of producing
a changeable visual display without the requirement of external controls by using
a programmable semiconductor device and a changeable liquid crystal display, the display
being changeable from one visual presentation to another in accordance with instructions
from the programmable semiconductor device.
[0005] Advantages offered by the invention are that the display is realistic and imitative
of an animated display; the display apparatus may be made small such as in an article
of jewellery and worn on the person; no external controls are required to operate
the apparatus, and the apparatus may be reprogrammed for use with a different display
giving flexibility of choice.
[0006] In a preferred form of the invention, the semiconductor device and the LCD are combined
with a power source in an article of jewellery.
[0007] Embodiments of the invention will now be described by way of example with reference
to the accompanying drawings in which:-
Fig. 1 is a block diagram of a circuit for carrying out the present invention;
Fig. 2 is a block diagram of an alternative circuit for carrying out the present invention;
Fig. 3 is a block diagram similar to Fig. 1 including a programmable semiconductor
device for generating audio signals.
Fig, 4 is a block diagram similar to Fig. 3 with the programmable semiconductor device
for generating audio signals being mounted on a separate chip.
Fig. 5 is a block diagram similar to Fig. 2 including a programmable semiconductor
device for generating audio signals.
Figs 6a,6b,6c and 6d are schematic diagrams of a sequence of liquid crystal displays,
produced by the apparatus in accordance with the present invention.
[0008] Referring now to Fig. 1 a semiconductor device in the form of a 'chip' 1 has a electrical
circuitry located thereon fabricated by a low voltage complementary metal- oxide-semiconductor
(CMOS) process or similar process.
[0009] An N-bit binary counter 2 is connected to a decoder 6 which decodes the said counter's
output state to select an address of a preprogrammed read-only-memory (PROM) 3 to
which it is connected. One of the decoder outputs 4 is preprogrammed to reset the
binary counter 2 in order that the programme sequence may be recycled after a specified
number of steps. The PROM 3 has M parallel outputs 5 which are connected to liquid
crystal display drivers 8, and the drivers 8 also have M parallel outputs 9 which
are connected to the front plane electrodes (not shown in the interest of clarity)
of a liquid crystal display (Figs 6a-6d).
[0010] A first oscillator 10 is connected to the N-bit binary counter 2, and a second oscillator
11 is connected to the liquid crystal display (LCD) drivers 8 and to the back plane
electrode (not shown) of the liquid crystal display.
[0011] The frequencies of the first and second oscillators are set by the value of resistive
and capacitive components (not shown) which are located external to the semiconductor
chip 1.
[0012] Power is supplied to the chip via terminals 12 and 13 which are at a potential of
typically 41 volts and zero volts respectively.
[0013] The data which has been 'read' from the PROM 3 is transferred in M parallel rows
by the PROM outputs 5 to the liquid crystal display drivers 8 in accordance with the
frequency of the oscillator 10.
[0014] The visual display data is caused to oscillate according to the frequency of oscillator
11 such that the data is either in-phase or in antiphase with the signal to the back
plane electrode. Signals in antiphase cause the electrode elements to change state
and reflect light giving the appearance of darkening while those in pahse cause the
appearance of the visual display to transmit light and so to remain unchanged.
[0015] The visual display data is then transferred from the drivers 8 to M crystal display
electrodes in accordance with the frequency of oscillator 11, the frequency of which
is typically 100 Hz to prevent deterioration of the liquid crystal display. Thus,
data signals are presented to the front plane electrodes in phase, or in antiphase,
with signals from the oscillator 11 to the back plane electrode of the liquid crystal
display.
[0016] The visual display thus presented at a given time is representative of the particular
row of data read from the preprogrammed read-only-memory 3 for example Fig. 6a. The
visual display presented is continuously changedin accordance with the program in
the PROM 3 from the display shown in Fig 6a through displays in Figs 6b,6c to Fig.
6d and to Fig. 6a. This gives the effect of an animated display. The frequency of
change is controlled by the oscillator 10, which is typically 0.1 hZ to 2 Hz.
[0017] The number of electrodes of the liquid crystal display (M) and the number of steps
in the display sequency (2
N) should be as large as possible to provide maximum display versatility. Maximum values
of N and M are typically 5 and 30 respectively.
[0018] Referring now to Fig. 2, an N-bit shift register 14 and NOR gate 15 are connected
to the PROM 3 in place of the binary counter 2 and decoder 6, and a latch buffer 7
is inserted between the M parallel outputs 5 and the LCD drivers 8. The outputs 7a
of the latch buffer 7 are connected to the LCD drivers 8, and the oscillator 10 is
also connected to the latch buffers 7, otherwise the circuit is.the same as for Fig.
1
[0019] In use, the shift register 14 is clocked by the oscillator 10 which then sends an
electrical signal corresponding to a logic "1" to the PROM 3 enabling data corresponding
to a particular visual display to be read. The NOR gate 15 ensures that there is only
one logic "1" in the shift register at any one time. The data which has been read
is transfered in M parallel rows by the PROM outputs 5 to the latch buffers 7. The
data is then transferred from the latch buffers 7 to the LCD drivers 8 in accordcance
with the frequency of the oscillator 10. The control of the display by the oscillator
11, is the same as for the first circuit shown in Fig. 1.
[0020] The external resistor of the oscillator 10 is variable so that the frequency of the
change of the visual display can be adjusted manually, which is an advantage of the
apparatus according to the present invention.
[0021] The circuit shown in Fig. 3 is the same as the circuit of Fig. 1 except for the addition
of a second 2
NxL PROM 17 located in the integrated circuit on the chip 1. The inputs 16 to the chip
are the same 2
N outputs from the decoder 6. The L outputs 18 from the PROM 17 are fed to a speech
or tone generator (not shown) so that the changeable visual display is complemented
by a synchronised varying speech or tone signal. The circuit shown in Fig. 4 is the
same as Fig. 3 except that the second 2
Nx L PROM 17 is located externally of the chip 1. The PROM 17 may be a commercially
available chip and its inputs 16 are taken from the outputs of the binary counter
2. This is because the address commands are decoded on a decoder located on the PROM
17. The outputs of 18 of the PROM 17 are fed to a speech or tone generator.
[0022] The circuit shown in Fig. 5 includes a second N x L PROM 17 located in the integrated
circuit of the chip 1. The N inputs 16 of the PROM 17 are taken from the outputs of
the shift register 14. The L outputs 18 from the PROM 17 are fed to a latch 19 and
the outputs 20 from the latch are fed to a tone or speech generator (not shown in
the interest of clarity). The circuit configuration shown in Fig 2 is not suitable
for interfacing with a commercial PROM.
[0023] On processing mask will be unique to a particular liquid crystal design. The mask
will contain data by which memory transistors in the read-only-memory are enabled
or disenabled to provide the required output bit pattern. A typical display sequence
is shown in Figs 6a-6d.
[0024] A further advantage is that the CMOS-based operation requires very low power consumption,
resulting in continuous operation, over a period of a year or more, being achieved
without battry renewal.
[0025] Although it is envisaged that the present invention described in this embodiment
will have application in electronic jewellery it should be also realised that the
present invention will have application in many other fields such as advertising and
learning methods without departing from the scope of the invention. Thus the visual
display combined with the audio output synchronised to the display provides a useful
learning aid.
1. Changeable liquid crystal display apparatus characterised by a programmable semiconductor
device (3) a liquid crystal display, liquid crystal display driver means (8) connected
between the programmable semiconductor device (3) and the liquid crystal display,
the visual presentation of the liquid crystal display being controlled by signals
from said programmable semiconductor device, control means (2,6;14,15) connected to
said programmable semiconductor device for varying the signals from said device to
said liquid crystal display whereby, when said control means varies said signals from
said programmable semiconductor device to said liquid crystal display, said liquid
crystal display changes from one visual presentation to another.
2. Changeable liquid crystal display apparatus as claimed in claim 1 characterised
in that said programmable semiconductor (3) is a programmable-read-only-memory (PROM)
located on an integrated circuit (1), said control means (2,6;14,15) and said display
driver means (8) being located on the integrated circuit.
3. Changeable liquid crystal display apparatus as claimed in claim 2 characterised
in that the integrated circuit includes a first oscillator (10) and a second oscillator
(11), the first oscillator controlling the frequency of the change of the liquid crystal
display, the second oscillator controlling the frequency of the data presented to
the liquid crystal display from the display driver means (8).
4. Changeable liquid crystal display apparatus as claimed in any preceding claim characterised
in that the control is a binary counter (2) and a decoder (6), the outputs of the
counter (2) being connected to the decoder (6) and the outputs of the decoder being
connected to said PROM (3), and one output (4) of the decoder being connected to the
binary counter (2) whereby a counting sequence of the binary counter is repeated after
a predetermined number of steps.
5. Changeable liquid crystal display apparatus as claimed in any one of claims 1-3
characterised in that said control means is a shift register (14) and a NOR gate (15),
the outputs of the shift register (14) being connected to the PROM (3) and to the
NOR gate (14) and the output of the NOR gate being connected to the shift register.
6. Changeable liquid crystal display apparatus as claimed in claim 5 characterised
in that the outputs (5) of the PROM (2) are connected to a latch buffer means (7),
the outputs (7a) of the latch buffer means being connected to the inputs of the liquid
crystal display driver means (8).
7. Changeable liquid crystal display apparatus as claimed in claim 6 characterised
in that the first oscillator (10) is also connected to the latch buffer means (7).
8. Changeable liquid crystal display apparatus as claimed in any preceding claim characterised
in that the liquid crystal display includes a plurality of electrodes, said electrodes
being arranged in at least two groups to form at least two respective visual presentations
when signals from the PROM (2) are applied to the respective electrode groups, the
presentation of the display being changed in accordance with the frequency of the
first oscillator (10).
9. Changeable liquid crystal display apparatus as claimed in any preceding claim characterised
in that the frequency of the first oscillator (10) is variable externally of the integrated
circuit whereby the frequency of change of the presentation of the liquid crystal
display can be effected manually. '
10. Changeable liquid crystal display apparatus as claimed in any one of claims 1-4
characterised in that a second PROM (17) is located on said integrated circuit (1),
said second PROM (17) having an input (16) connected to the output of the decoder
(6), and having an output (18) connected to an audio generator.
11. Changeable liquid crystal display apparatus as claimed in any one of claims 1-4
characterised in that a second PROM (17) is located externally of said integrated
circuit (1), said second PROM (17) having an input (16) connected to the output of
the binary counter (2), and an input (18) connected to an audio generator.
12. Changeable liquid crystal display apparatus as claimed in any one of claims 1,2,3
or 5 characterised in that a second PROM (17) is connected on said integrated circuit
(1), said second PROM having an input connected to the output (16) of the shift register
(14) and an input (18) connected to an audio generator.